Radiosurgery scope of practice in Canada: A report of the Canadian association of radiation oncology (CARO) radiosurgery advisory committee

International Nuclear Information System (INIS)

Roberge, David; Menard, Cynthia; Bauman, Glenn; Chan, Alex; Mulroy, Liam; Sahgal, Arjun; Malone, Shawn; McKenzie, Michael; Schroeder, Garry; Fortin, Marie-Andree; Ebacher, Annie; Milosevic, Michael

2010-01-01

Radiosurgery has a long history in Canada. Since the treatment of the first patient at the McGill University Health Center in 1985, radiosurgery programs have been developed from coast to coast. These have included multidisciplinary teams of radiation oncologists, neurosurgeons, medical physicists, radiation technologists and other health professionals. In 2008, the CARO Board of Directors requested that a working group be formed to define the role of the radiation oncologist in the practice of radiosurgery. Taking into account evolving technology, changing clinical practice and current scope of practice literature, the working group made recommendations as to the role of the radiation oncologists. These recommendations were endorsed by the Canadian Association of Radiation Oncology board of directors in September 2009 and are present herein. It is recognized that patients benefit from a team approach to their care but it is recommended that qualified radiation oncologists be involved in radiosurgery delivery from patient consultation to follow-up. In addition, radiation oncologists should continue to be involved in the administrative aspects of radiosurgery programs, from equipment selection to ongoing quality assurance/quality improvement.

A geometrically based method for automated radiosurgery planning

International Nuclear Information System (INIS)

Wagner, Thomas H.; Yi Taeil; Meeks, Sanford L.; Bova, Francis J.; Brechner, Beverly L.; Chen Yunmei; Buatti, John M.; Friedman, William A.; Foote, Kelly D.; Bouchet, Lionel G.

2000-01-01

Purpose: A geometrically based method of multiple isocenter linear accelerator radiosurgery treatment planning optimization was developed, based on a target's solid shape. Methods and Materials: Our method uses an edge detection process to determine the optimal sphere packing arrangement with which to cover the planning target. The sphere packing arrangement is converted into a radiosurgery treatment plan by substituting the isocenter locations and collimator sizes for the spheres. Results: This method is demonstrated on a set of 5 irregularly shaped phantom targets, as well as a set of 10 clinical example cases ranging from simple to very complex in planning difficulty. Using a prototype implementation of the method and standard dosimetric radiosurgery treatment planning tools, feasible treatment plans were developed for each target. The treatment plans generated for the phantom targets showed excellent dose conformity and acceptable dose homogeneity within the target volume. The algorithm was able to generate a radiosurgery plan conforming to the Radiation Therapy Oncology Group (RTOG) guidelines on radiosurgery for every clinical and phantom target examined. Conclusions: This automated planning method can serve as a valuable tool to assist treatment planners in rapidly and consistently designing conformal multiple isocenter radiosurgery treatment plans.

Gamma Knife Radiosurgery for Acromegaly

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John D. Rolston

2012-01-01

Full Text Available Acromegaly is debilitating disease occasionally refractory to surgical and medical treatment. Stereotactic radiosurgery, and in particular Gamma Knife surgery (GKS, has proven to be an effective noninvasive adjunct to traditional treatments, leading to disease remission in a substantial proportion of patients. Such remission holds the promise of eliminating the need for expensive medications, along with side effects, as well as sparing patients the damaging sequelae of uncontrolled acromegaly. Numerous studies of radiosurgical treatments for acromegaly have been carried out. These illustrate an overall remission rate over 40%. Morbidity from radiosurgery is infrequent but can include cranial nerve palsies and hypopituitarism. Overall, stereotactic radiosurgery is a promising therapy for patients with acromegaly and deserves further study to refine its role in the treatment of affected patients.

Stereotactic radiosurgery for spinal metastases: a literature review

International Nuclear Information System (INIS)

Joaquim, Andrei Fernandes; Ghizoni, Enrico; Tedeschi, Helder; Pereira, Eduardo Baldon; Giacomini, Leonardo Abdala

2013-01-01

Objective: The spine is the most common location for bone metastases. Since cure is not possible, local control and relief of symptoms is the basis for treatment, which is grounded on the use of conventional radiotherapy. Recently, spinal radiosurgery has been proposed for the local control of spinal metastases, whether as primary or salvage treatment. Consequently, we carried out a literature review in order to analyze the indications, efficacy, and safety of radiosurgery in the treatment of spinal metastases. Methods: We have reviewed the literature using the PubMed gateway with data from the Medline library on studies related to the use of radiosurgery in treatment of bone metastases in spine. The studies were reviewed by all the authors and classified as to level of evidence, using the criterion defined by Wright. Results: The indications found for radiosurgery were primary control of epidural metastases (evidence level II), myeloma (level III), and metastases known to be poor responders to conventional radiotherapy – melanoma and renal cell carcinoma (level III). Spinal radiosurgery was also proposed for salvage treatment after conventional radiotherapy (level II). There is also some evidence as to the safety and efficacy of radiosurgery in cases of extramedullar and intramedullar intradural metastatic tumors (level III) and after spinal decompression and stabilization surgery. Conclusion: Radiosurgery can be used in primary or salvage treatment of spinal metastases, improving local disease control and patient symptoms. It should also be considered as initial treatment for radioresistant tumors, such as melanoma and renal cell carcinoma. (author)

Treat high cervical spinal arteriovenous malformation with Cyberknife radiosurgery

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Yu-Fen Huang

2014-01-01

Full Text Available This paper describes the use of CyberKnife radiosurgery in the treatment of accidentally found cervical spinal arteriovenous malformation (AVM. We present the case of a patient with cervical spinal AVM, who developed progressive neck pain, gait disturbance, urine and stool incontinence 2 weeks after the fell down accident. The patient underwent CyberKnife radiosurgery. After CyberKnife radiosurgery for 2 years, the patient′s neck pain diminished and was able to keep the walk without any assistance. The management of cervical spinal AVM varies. This patient demonstrated a successful treatment of cervical spinal AVM with CyberKnife radiosurgery.

Value of stereotactic radiosurgery in patients with multiple brain metastases

International Nuclear Information System (INIS)

Chen Jie; Lin Zhiguo; Li Qingguo; Shen Hong

2002-01-01

Objective: To analyze the prognostic factors and evaluate the effect of stereotactic radiosurgery for patients with multiple brain metastases. Methods: Comparison was made in 53 such patients treated by stereotactic radiosurgery plus radiotherapy and 53 treated by radiotherapy alone. Patients were matched-paired according to the following criteria: age, Karnofsky performance scale (KPS) before treatment, extent of systemic cancer and number of brain metastasis. Forty patients had stereotactic radiosurgery, 13 patients stereotactic fractionated radiosurgery. In the stereotactic radiosurgery group, the patients were given a mean marginal dose of 20 Gy. Methods of stereotactic fractionated radiosurgery was 4-12 Gy per fraction , twice a week to a total dose of 15-30 Gy. Whole brain radiotherapy was given immediately after stereotactic radiosurgery. For patients treated by radiotherapy alone, the entire brain was treated by 30-40 Gy in 3-4 weeks. Results: The median survival was 11.6 months in stereotactic radiosurgery plus radiotherapy and 6.7 months in radiotherapy alone. The one year survival rate and one year local control rate were 44.3%, 17.1% and 50.9%, 13. 2%. Those with KPS increased after treatment gave 1-year survivals of 69.8% and 30.2%, respectively. The validity rates in CT or MRI three months after treatment were 82.0% and 55.0%. The difference in the two groups was found to be statistically significant (P < 0.01). 23.3% of death in the stereotactic radiosurgery plus radiotherapy group was due to brain metastasis vs 51.0% in the radiotherapy alone group (P < 0.05). Complication of the two groups was similar. Conclusion: Stereotactic radiosurgery plus radiotherapy is superior to radiotherapy alone for multiple brain metastases in improving the local control and ultimate outcome

Embolization with Gamma Knife Radiosurgery of Giant Intracranial Arteriovenous Malformations.

Science.gov (United States)

Chun, Dong Hyun; Kim, Moo Seong; Kim, Sung Tae; Paeng, Sung Hwa; Jeong, Hae Woong; Lee, Won Hee

2016-01-01

Giant arteriovenous malformations (i.e., those greater than 6 cm maximum diameter or volume > 33 cc) are difficult to treat and often carry higher treatment morbidity and mortality rates. In our study, we reviewed the angiographic results and clinical outcomes for 11 patients with giant arteriovenous malformations who were treated between 1994 and 2012. The patients selected included 9 males (82%) and 2 females (18%). Their presenting symptoms were hemorrhage (n=2; 18%), seizure (n=7; 64%), and headache (n=2; 12%). Nine patients were Spetzler-Martin Grade III, 2 were Spetzler-Martin Grade IV. The mean arteriovenous malformation volume was 41 cc (33-52 cc). The mean age of the patients was 45.1 years (24-57 years) and the mean radiation dose delivered to the margin of the nidus was 14.2 Gy. Ten patients received pre-Gamma Knife radiosurgery embolization and Gamma Knife radiosurgery, 1 patient received pre-Gamma Knife radiosurgery embolization and Gamma Knife radiosurgery twice and the interval between Gamma Knife radiosurgeries was 3 months. The complete obliteration rate following Gamma Knife radiosurgery was 36%, subtotal obliteration ( > 70% decreased size of nidus) was 36%, and partial obliteration was 28%. One patient experienced a small hemorrhage after embolization. Combined embolization and Gamma Knife radiosurgery showed successful obliteration of the arteriovenous malformation nidus. The use of embolization to initially reduce nidus size followed by Gamma Knife radiosurgery improves the treatment results. Repeated Gamma Knife radiosurgery should be a treatment option when there is a small nidus remnant.

Stereotactic radiosurgery using the gamma knife

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Kawamoto, Shunsuke; Sasaki, Tomio; Matsutani, Masao; Takakura, Kintomo; Terahara, Atsuro (Tokyo Univ. (Japan). Faculty of Medicine)

1992-03-01

Since stereotactic radiosurgery using a gamma knife was developed in 1968 by Leksell, it has been used with increasing frequency in Japan. During the period from June 19, 1990 through December 20, 1991, 218 patients have been treated with stereotactic radiosurgery using a gamma knife. Of them, 116 had vascular lesions (116), including arteriovenous malformation (114), dural arteriovenous malformation (one), and cerebral aneurysm (one); and the other 102 had tumorous lesions, including acoustic neurinoma (48), meningioma (26), pituitary tumor (11), metastatic tumor (7), germ cell tumor (3), glioma (2), hemangioblastoma (2), chordoma (one), craniopharyngioma (one), and trigeminal neurinoma (one). In this article, candidates of stereotactic radiosurgery using a gamma knife are discussed, with particular attention to clinical results of the aforementioned 218 patients. (N.K.) 54 refs.

Stereotactic Radiosurgery for Classical Trigeminal Neuralgia

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Henry Kodrat

2016-04-01

Full Text Available Trigeminal neuralgia is a debilitating pain syndrome with a distinct symptom mainly excruciating facial pain that tends to come and go unpredictably in sudden shock-like attacks. Medical management remains the primary treatment for classical trigeminal neuralgia. When medical therapy failed, surgery with microvascular decompression can be performed. Radiosurgery can be offered for classical trigeminal neuralgia patients who are not surgical candidate or surgery refusal and they should not in acute pain condition. Radiosurgery is widely used because of good therapeutic result and low complication rate. Weakness of this technique is a latency period, which is time required for pain relief. It usually ranges from 1 to 2 months. This review enlightens the important role of radiosurgery in the treatment of classical trigeminal neuralgia.

Robotic Radiosurgery. Treating prostata cancer and related genitourinary applications

International Nuclear Information System (INIS)

Ponsky, Lee E.

2012-01-01

Prostate cancer is the most common cancer among North American and European men, but its treatment continues to be problematic owing to serious side-effects, including erectile dysfunction, urinary incontinence, and potential lower GI complications. Robotic radiosurgery offers a novel, rapid, non-invasive outpatient treatment option for prostate cancer that combines robotics, advanced image-guided motion detection, and automated real-time corrective spatial positioning with submillimeter precision. This book examines all aspects of the treatment of prostate cancer with robotic radiosurgery. After introductory sections on radiosurgery as a multidisciplinary practice and specific issues relating to prostate cancer, the important challenge posed by prostate motion when administering radiation therapy is examined in depth, with detailed discussion as to how image-guided robotic radiosurgery overcomes this problem by continously identifying the precise location of the prostate throughout the course of treatment. A further major section is devoted to a discussion of techniques and potential radiobiological and clinical advantages of hypofractionated radiation delivery by means of robotic radiosurgery systems. The book closes by discussing other emerging genitourinary applications of robotic radiosurgery. All of the authors are experts in their field who present a persuasive case for this fascinating technique. (orig.)

Robotic Radiosurgery. Treating prostata cancer and related genitourinary applications

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Ponsky, Lee E. (ed.) [Case Western Reserve University School of Medicine, Cleveland, OH (United States). University Hospitals Case Medical Center

2012-07-01

Prostate cancer is the most common cancer among North American and European men, but its treatment continues to be problematic owing to serious side-effects, including erectile dysfunction, urinary incontinence, and potential lower GI complications. Robotic radiosurgery offers a novel, rapid, non-invasive outpatient treatment option for prostate cancer that combines robotics, advanced image-guided motion detection, and automated real-time corrective spatial positioning with submillimeter precision. This book examines all aspects of the treatment of prostate cancer with robotic radiosurgery. After introductory sections on radiosurgery as a multidisciplinary practice and specific issues relating to prostate cancer, the important challenge posed by prostate motion when administering radiation therapy is examined in depth, with detailed discussion as to how image-guided robotic radiosurgery overcomes this problem by continously identifying the precise location of the prostate throughout the course of treatment. A further major section is devoted to a discussion of techniques and potential radiobiological and clinical advantages of hypofractionated radiation delivery by means of robotic radiosurgery systems. The book closes by discussing other emerging genitourinary applications of robotic radiosurgery. All of the authors are experts in their field who present a persuasive case for this fascinating technique. (orig.)

Treatment planning optimization for linear accelerator radiosurgery

International Nuclear Information System (INIS)

Meeks, Sanford L.; Buatti, John M.; Bova, Francis J.; Friedman, William A.; Mendenhall, William M.

1998-01-01

Purpose: Linear accelerator radiosurgery uses multiple arcs delivered through circular collimators to produce a nominally spherical dose distribution. Production of dose distributions that conform to irregular lesions or conformally avoid critical neural structures requires a detailed understanding of the available treatment planning parameters. Methods and Materials: Treatment planning parameters that may be manipulated within a single isocenter to provide conformal avoidance and dose conformation to ellipsoidal lesions include differential arc weighting and gantry start/stop angles. More irregular lesions require the use of multiple isocenters. Iterative manipulation of treatment planning variables can be difficult and computationally expensive, especially if the effects of these manipulations are not well defined. Effects of treatment parameter manipulation are explained and illustrated. This is followed by description of the University of Florida Stereotactic Radiosurgery Treatment Planning Algorithm. This algorithm organizes the manipulations into a practical approach for radiosurgery treatment planning. Results: Iterative treatment planning parameters may be efficiently manipulated to achieve optimal treatment plans by following the University of Florida Treatment Planning Algorithm. The ability to produce conformal stereotactic treatment plans using the algorithm is demonstrated for a variety of clinical presentations. Conclusion: The standard dose distribution produced in linear accelerator radiosurgery is spherical, but manipulation of available treatment planning parameters may result in optimal dose conformation. The University of Florida Treatment Planning Algorithm organizes available treatment parameters to efficiently produce conformal radiosurgery treatment plans

Combined embolization and gamma knife radiosurgery for cerebral arteriovenous malformations

International Nuclear Information System (INIS)

Guo, W.Y.; Wikholm, G.; Karlsson, B.; Lindquist, C.; Svendsen, P.; Ericson, K.

1993-01-01

In a study of 46 patients with cerebral arteriovenous malformations (AVMs) the value of combining embolization and gamma knife radiosurgery was assessed. In 35 patients with large grade III to V AVMs (Spetzler-Martin system) staged combined treatment was planned. In 11 patients, radiosurgery complemented embolization for a residual AVM. The number of embolization sessions ranged from 1 to 7 (median 2). Twenty-six patients needed multiple embolization sessions. In 28 patients the grade of AVMs decreased as a result of embolization. In 16 patients collateral feeding vessels developed after embolization which made delineation of the residual nidus difficult. The time lag between the last embolization and radiosurgery ranged from 1 to 24 months (median 4). Nineteen of 35 large grade III to V AVMs were possible to treat by radiosurgery following embolization. In the 46 patients complications occurred in 9 from embolization and in 2 from radiosurgery. Two patients had transient and 9 had permanent neurologic deficits. It is concluded that embolization facilitates radiosurgery for some large AVMs and therefore this combined treatment has a role in the management of AVMs. (orig.)

A multi-national report on methods for institutional credentialing for spine radiosurgery

International Nuclear Information System (INIS)

Gerszten, Peter C; Shin, John H; Winey, Brian; Oh, Kevin; Sweeney, Reinhart A; Guckenberger, Matthias; Sahgal, Arjun; Sheehan, Jason P; Kersh, Ronald; Chen, Stephanie; Flickinger, John C; Quader, Mubina; Fahim, Daniel; Grills, Inga

2013-01-01

Stereotactic body radiotherapy and radiosurgery are rapidly emerging treatment options for both malignant and benign spine tumors. Proper institutional credentialing by physicians and medical physicists as well as other personnel is important for the safe and effective adoption of spine radiosurgery. This article describes the methods for institutional credentialing for spine radiosurgery at seven highly experienced international institutions. All institutions (n = 7) are members of the Elekta Spine Radiosurgery Research Consortium and have a dedicated research and clinical focus on image-guided spine radiosurgery. A questionnaire consisting of 24 items covering various aspects of institutional credentialing for spine radiosurgery was completed by all seven institutions. Close agreement was observed in most aspects of spine radiosurgery credentialing at each institution. A formal credentialing process was believed to be important for the implementation of a new spine radiosurgery program, for patient safety and clinical outcomes. One institution has a written policy specific for spine radiosurgery credentialing, but all have an undocumented credentialing system in place. All institutions rely upon an in-house proctoring system for the training of both physicians and medical physicists. Four institutions require physicians and medical physicists to attend corporate sponsored training. Two of these 4 institutions also require attendance at a non-corporate sponsored academic society radiosurgery course. Corporate as well as non-corporate sponsored training were believed to be complimentary and both important for training. In 5 centers, all cases must be reviewed at a multidisciplinary conference prior to radiosurgery treatment. At 3 centers, neurosurgeons are not required to be involved in all cases if there is no evidence for instability or spinal cord compression. Backup physicians and physicists are required at only 1 institution, but all institutions have more

Clinical practice of image-guided spine radiosurgery - results from an international research consortium

Directory of Open Access Journals (Sweden)

Guckenberger Matthias

2011-12-01

Full Text Available Abstract Background Spinal radiosurgery is a quickly evolving technique in the radiotherapy and neurosurgical communities. However, the methods of spine radiosurgery have not been standardized. This article describes the results of a survey about the methods of spine radiosurgery at five international institutions. Methods All institutions are members of the Elekta Spine Radiosurgery Research Consortium and have a dedicated research and clinical focus on image-guided radiosurgery. The questionnaire consisted of 75 items covering all major steps of spine radiosurgery. Results Strong agreement in the methods of spine radiosurgery was observed. In particular, similarities were observed with safety and quality assurance playing an important role in the methods of all institutions, cooperation between neurosurgeons and radiation oncologists in case selection, dedicated imaging for target- and organ-at-risk delineation, application of proper safety margins for the target volume and organs-at-risk, conformal planning and precise image-guided treatment delivery, and close clinical and radiological follow-up. In contrast, three major areas of uncertainty and disagreement were identified: 1 Indications and contra-indications for spine radiosurgery; 2 treatment dose and fractionation and 3 tolerance dose of the spinal cord. Conclusions Results of this study reflect the current practice of spine radiosurgery in large academic centers. Despite close agreement was observed in many steps of spine radiosurgery, further research in form of retrospective and especially prospective studies is required to refine the details of spinal radiosurgery in terms of safety and efficacy.

Linear accelerator radiosurgery in treatment of central neurocytomas

International Nuclear Information System (INIS)

Martin, J.M.; Katati, M.; Arjona, V.; Lopez, E.; Olivares, G.; Hernandez, V.; Bullejos, J.A.; Arregui, G.; Busquier, H.; Minguez, A.

2003-01-01

The purpose of this report was to review our experience with stereotactic radiosurgery in the management of patients with residual neurocytomas after initial surgery. Between October 1996 and December 2001, four patients with central neurocytoma were treated by surgery and subsequently underwent linear accelerator (LINAC) radiosurgery. Two of the patients were cured, one exhibited a significant reduction in tumour size and the fourth remains stable. All four patients are alive and well. In cases of small residual tumours or recurrences radio-surgery allows open surgery to be avoided and is a safe and potentially effective approach. (author)

Robotic radiosurgery. Treating tumors that move with respiration

International Nuclear Information System (INIS)

Urschel, Harold C. Jr.; Kresl, John J.; Luketich, James D.; Papiez, Lech; Timmerman, Robert D.; Schulz, Raymond A.

2007-01-01

Addresses in detail all aspects of the use of robotic radiosurgery to treat tumors of the lung, liver, and pancreas Includes full consideration of tumor tracking techniques, dosimetry, radiobiology, and fiducial placement strategies Written by leading experts Includes many high quality illustrations Stereotactic radiosurgery continues to evolve in ways that allow this powerful technology to reach and treat more tumors in more patients. This volume in the Robotic Radiosurgery series is devoted to theory and practice in the emerging field of stereotactic radiosurgery (also called stereotactic body radiation therapy) for extracranial tumors, particularly those that move as patients breathe. The book is divided into six sections. The first three sections address tumor motion due to respiration and tumor tracking techniques; dosimetry, radiobiology, and imaging; and fiducial placement systems. The fourth and fifth sections then discuss in depth the use of robotic radiosurgery to treat lung and abdominal tumors, respectively, and a final section explains emerging concepts and techniques. Within this framework, detailed information is provided on the technology and methodology for delivery of high doses of radiation to moving targets, radiobiological and radiological principles, and the challenges faced by clinicians performing extracranial stereotactic radiosurgery. Furthermore, there are thorough reviews of the general clinical literature on stereotactic radiation treatment of tumors of the lungs, liver, and pancreas, and the latest clinical data from clinicians conducting clinical studies using the CyberKnife registered Robotic Radiosurgery System. Special attention is given to the frameless robotic radiosurgery device known as the CyberKnife, the only image-guided radiosurgery system that utilizes intelligent robotics to track, detect, and correct for changes in tumor position during treatments. Tumors that move with respiration are treated with the CyberKnife using a

Robotic radiosurgery. Treating tumors that move with respiration

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Urschel, Harold C. Jr. [Baylor University Medical Center, Dallas, TX (United States). Chair of Cardiovascular and Thoracic Surgical Research, Education and Clinical Excellence; Kresl, John J. [Arizona Oncology Services at St. Joseph' s Hospital and Medical Center, Phoenix, AZ (United States). Dept. of Radiation Oncology; Luketich, James D. [University of Pittsburgh Medical Center PUH, Pittsburgh, PA (United States). The Heart, Lung and Esophageal Surgery Inst.; Papiez, Lech; Timmerman, Robert D. [University of Texas Southwestern Medical Center, Dallas, TX (United States). Dept. of Radiation Oncology; Schulz, Raymond A. (eds.)

2007-07-01

Addresses in detail all aspects of the use of robotic radiosurgery to treat tumors of the lung, liver, and pancreas Includes full consideration of tumor tracking techniques, dosimetry, radiobiology, and fiducial placement strategies Written by leading experts Includes many high quality illustrations Stereotactic radiosurgery continues to evolve in ways that allow this powerful technology to reach and treat more tumors in more patients. This volume in the Robotic Radiosurgery series is devoted to theory and practice in the emerging field of stereotactic radiosurgery (also called stereotactic body radiation therapy) for extracranial tumors, particularly those that move as patients breathe. The book is divided into six sections. The first three sections address tumor motion due to respiration and tumor tracking techniques; dosimetry, radiobiology, and imaging; and fiducial placement systems. The fourth and fifth sections then discuss in depth the use of robotic radiosurgery to treat lung and abdominal tumors, respectively, and a final section explains emerging concepts and techniques. Within this framework, detailed information is provided on the technology and methodology for delivery of high doses of radiation to moving targets, radiobiological and radiological principles, and the challenges faced by clinicians performing extracranial stereotactic radiosurgery. Furthermore, there are thorough reviews of the general clinical literature on stereotactic radiation treatment of tumors of the lungs, liver, and pancreas, and the latest clinical data from clinicians conducting clinical studies using the CyberKnife {sup registered} Robotic Radiosurgery System. Special attention is given to the frameless robotic radiosurgery device known as the CyberKnife, the only image-guided radiosurgery system that utilizes intelligent robotics to track, detect, and correct for changes in tumor position during treatments. Tumors that move with respiration are treated with the Cyber

Value of gamma knife radiosurgery for tumors invading cavernous sinus

International Nuclear Information System (INIS)

Jokura, Hidefumi; Yoshimoto, Takashi

1999-01-01

The usefulness of radiosurgery for cavernous sinus tumors was evaluated based on our experience and recent published reports from other institutes. Twenty-six meningiomas involving the cavernous sinus were treated by radiosurgery. The length of follow-up average 3 years. Tumors regressed in 40% and remained stable in 56% of cases. A total of 96% of the tumors were controlled with only a few minor complications. We believe surgical resection to reduce the volume of the tumor without causing new neurological deficits, followed by radiosurgery on the tumor located in the cavernous sinus is the best choice in many cases. Twenty-five pituitary adenomas with cavernous sinus invasion were treated by a combination of transsphenoidal removal and radiosurgery. All the tumors are controlled in terms of volume during the follow-up (average of 34 months). There were no new neurological deficits, including visual disturbance. Hormone elevation was able to be corrected at an early stage without pituitary insufficiency more by radiosurgery than by fractionated radiation. However, to obtain good results by radiosurgery, it must be preceded by complete surgical decompression of optic nerves and chiasma from the tumor. (author)

Radiosurgery for pituitary adenomas; Radiocirurgia nos adenomas hipofisarios

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Castro, Douglas Guedes de; Salvajoli, Joao Victor; Canteras, Miguel Montes; Cecilio, Soraya A. Jorge [Instituto de Radiocirurgia Neurologica, Sao Paulo, SP (Brazil)]. E-mail: dougguedes@uol.com.br

2006-12-15

Pituitary adenomas represent nearly 15% of all intracranial tumors. Multimodal treatment includes microsurgery, medical management and radiotherapy. Microsurgery is the primary recommendation for nonfunctioning and most of functioning adenomas, except for prolactinomas that are usually managed with dopamine agonist drugs. However, about 30% of patients require additional treatment after microsurgery for recurrent or residual tumors. In these cases, fractionated radiation therapy has been the traditional treatment. More recently, radiosurgery has been established as a treatment option. Radiosurgery allows the delivery of prescribed dose with high precision strictly to the target and spares the surrounding tissues. Therefore, the risks of hypopituitarism, visual damage and vasculopathy are significantly lower. Furthermore, the latency of the radiation response after radiosurgery is substantially shorter than that of fractionated radiotherapy. The goal of this review is to define the efficacy, safety and role of radiosurgery for treatment of pituitary adenomas and to present the preliminary results of our institution. (author)

Stereotactic radiosurgery: incision less surgery

International Nuclear Information System (INIS)

Alvarez, Victor M.; Palma, Raul B.

1997-01-01

Stereotactic Radiosurgery (SRS) involves the application of focused high dose, high energy radiation to precisely (stereotactically) localized targets in the head without opening the skull for the purpose of destroying pathologic tissues like tumors, and also for producing discrete lesions for the relief of certain functional disorders. This procedure was pioneered by Lars Leksel in the 1950s and has progressively been refined with the development of more powerful computer technology and more precise and safer radiation delivery systems. The used of the Linear Accelerator (LINAC)- based radiosurgery system would be the most cost-effective and appropriate system for this treatment

International Radiosurgery Support Association

Science.gov (United States)

... below: ? Brain Tumors Brain Disorders AVMs Radiosurgery Gamma Knife Linac Radiotherapy Overview Childhood Brain Tumors Radiation Therapy Radiation Injury Treatment Day Making a Decision Centers of Excellence BRAIN TALK® ...

The study on linac stereotactic radiosurgery for acoustic tumors

International Nuclear Information System (INIS)

Ohishi, Hitoshi

1995-01-01

We have designed and manufactured a new type of device for stereotactic radiosurgery characterized by the combined use of a rotatory chair and a linear accelerator. In this study, 20 acoustic tumors treated by our modality were evaluated by serial neuroimaging, neurofunctional outcome and, in a few cases, pathological findings of surgical specimens. Because tumor size usually changed very slowly after radiosurgery, 12 cases that had a minimum of 12 months of follow-up were employed in the analysis of tumor size. Serial neuroimaging studies revealed the reduction of tumor size in 3 cases and prevention of tumor growth in 7 cases, therefore, the rate of tumor control was evaluated as 83%. Growth of tumor size occurred in 3 cases, two were cases harbouring a large cyst in the tumor and another was a case of neurofibromatosis type 2. In 13 cases (68%), loss of the gadolinium enhancement effect inside the tumor was observed. This is a characteristic change after radiosurgery for acoustic tumors, and attributable to a necrotic change. Cranial nerve neuropathies as a complication also occurred (facial nerve palsy in 2 and trigeminal nerve dysfunction in 1). Adjacent parenchymal change appeared in 1 case. This patient had two prior operations and the tumor had an irregular shape, therefore, planning for radiosurgery encountered some difficulty. Hydrocephalus occurred in 1 case. Surgical specimens in 2 cases in which microsurgery was undertaken for growing tumors, revealed a necrotic tumor tissue and proliferation of fibrous tissue. In conclusion, our new device for stereotactic radiosurgery is particularly useful for the treatment of acoustic tumors. Similar therapeutic results of the gamma knife have been achieved. Radiosurgery is a recommendable treatment for acoustic tumors. However, the superiority of radiosurgery over microsurgery is still controversial and needs a longer term follow-up and multivariate analysis for a final conclusion. (author)

Treatment of epidermoid tumors with gamma knife radiosurgery: Case series.

Science.gov (United States)

Vasquez, Javier A Jacobo; Fonnegra, Julio R; Diez, Juan C; Fonnegra, Andres

2016-01-01

Epidermoid tumors (ETs) are benign lesions that are treated mainly by means of surgical resection, with overall good results. External beam radiotherapy is an alternative treatment for those recurrent tumors, in which a second surgery might not be the best choice for the patient. A little information exists about the effectiveness of gamma knife radiosurgery for the treatment of newly diagnosed and recurrent ETs. We present three cases of ETs treated with gamma knife radiosurgery. Case 1 is a 21-year-old female with an ET located in the left cerebellopontine angle (CPA) with symptoms related to VIII cranial nerve dysfunction. Symptom control was achieved and maintained after single session radiosurgery with gamma knife. Case 2 is a 59-year-old female patient with the history of trigeminal neuralgia secondary to a recurrent ET located in the left CPA. Significant pain improvement was achieved after treatment with gamma knife radiosurgery. Case 3 is a 29-year-old male patient with a CPA ET causing long lasting trigeminal neuralgia, pain relief was achieved in this patient after gamma knife radiosurgery. Long-term symptom relief was achieved in all three cases proving that gamma knife radiosurgery is a good and safe alternative for patients with recurrent or nonsurgically treated ETs.

Stereotactic radiosurgery in acoustic neurinomas

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Yamamoto, Masaaki; Noren, G. (Karolinska Hospital, Stockholm (Sweden))

1990-12-01

The records of 57 patients with 61 acoustic neurinomas treated with stereotatic radiosurgery at the Karolinska Hospital, Stockholm, from 1982 through 1984, were reviewed. Adequate radiological and clinical follow-up evaluations were available in these cases. An additional 8 patients were treated during this same period but were not included because of insufficient data. The tumors were evaluated with CT or MRI. Their post-operative follow-up period was 6-66 months (mean 28 months). Decrease of tumor size or no change was considered as a response to radiosurgery. This was found in 54 (88%) of the tumors. Small tumors with a diameter of less than 15 mm responded better (93%) than large ones (85%). Ninety-five percent of unilateral tumors and 74% of tumors associated with neurofibromatosis responded well. Seven tumors had definite radiographic signs of subsequent growth. Four were removed using standard microsurgical tequniques and three have so far not required further treatment. Facial and trigeminal nerve function was evaluated in 58 facial surfaces where tumors had been irradiated. Transient facial weakness developed in 9% and facial hypesthesia in 9% of the irradiated cases. The onset of these nerve dysfunction appeared with a latency period of 4 to 15 months after radiosurgery. Excluding the ears which had been totally deaf before the treatment, forty-one ears were evaluated fully by audiometry prior to and one year after irradiation. 30% of them had no change in hearing, 68% had a more or less pronouced deterioration and 2% had improvement. We regard efficiency in arresting tumor growth without endangering life, preservation of facial nerve function, and only a day of hospitalization as major benefits of radiosurgery. (author).

The strategy of the treatment for arteriovenous malformations by gamma knife radiosurgery

International Nuclear Information System (INIS)

Fukuoka, Seiji; Seo, Yoshinobu; Hyougo, Toshio; Sasaki, Takehiko; Toshima, Masahiko; Takeda, Rihei; Nakamura, Junichi; Suematu, Katsumi.

1992-01-01

Successful gamma knife radiosurgery depends on the volume of nidus of cerebral arteriovenous malformations (AVMs). Because of lower possibility of obliteration of large AVMs treated by gamma knife radiosurgery, embolization therapies were carried out in 10 cases out of 50 AVMs to reduce the volume of nidus before gamma knife radiosurgery. The strategy is as follows: 1) when the volume of nidus is less than 5 ml, gamma knife radiosurgery is selected as the first treatment; 2) when the procedure seems to be safely performed; 3) when the volume of nidus is over 10 ml, embolization should be tried in all cases. In this strategy, it is essential to evaluate the accurate volume of nidus before gamma knife radiosurgery to decide whether embolization should be carried out or not. Angiography with painless fixation of Leksell frame was thought to be best procedure to measure the accurate volume of nidus before gamma knife radiosurgery. (author)

Stereotactic Radiosurgery - Gamma Knife

Science.gov (United States)

... DE, Adler JR Jr, Ewend MG. Image-guided robotic radiosurgery. In: Winn RH, ed. Youmans Neurological Surgery . ... by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is ...

Tolerance of the human spinal cord to single dose radiosurgery

International Nuclear Information System (INIS)

Ryu, S.; Zhu, G.; Yin, F.-F.; Ajlouni, M.; Kim, J.H.

2003-01-01

Tolerance of the spinal cord to the single dose of radiation is not well defined. Although there are cases of human spinal cord tolerance from re-irradiation to the same cord level, the information about the tolerance of human spinal cord to single large dose of radiosurgery is not available. We carried out spinal radiosurgery to treat spinal metastasis and studied the single dose tolerance of the human spinal cord in an ongoing dose escalation paradigm. A total of 39 patients with 48 lesions of spinal metastasis were treated with single dose radiosurgery at Henry Ford Hospital. The radiosurgery dose was escalated from 8 Gy to 16 Gy at 2 Gy increment. The radiation dose was prescribed to periphery of the spinal tumor. The radiation dose to the spinal cord was estimated by computerized dosimetry. The median follow-up time was 10 months (range 6-18 months) from the radiosurgery. The endpoint of the study was to demonstrate the efficacy of the spinal radiosurgery and to determine the tolerance of human spinal cord to single dose radiosurgery. The dose to the spinal cord was generally less than 50 % of the prescribed radiation dose. The volume of the spinal cord that received higher than this dose was less than 20 % of the anterior portion of the spinal cord. Maximum single dose of 8 Gy was delivered to the anterior 20 % of the spinal cord in this dose escalation study. The dose volume histogram will be presented. There was no acute or subacute radiation toxicity detected clinically and radiologically during the maximum follow-up of 20 months. Further dose escalation is in progress. The single tolerance dose of the human spinal cord appears to be at least 8 Gy when it was given to the 20 % of the cord volume, although the duration of follow up is not long enough to detect severe late cord toxicity. This study offers a valuable radiobiological basis of the normal spinal cord tolerance, and opens spinal radiosurgery as a safe treatment for spinal metastasis

Experimental measurements of spatial dose distributions in radiosurgery treatments

International Nuclear Information System (INIS)

Avila-Rodriguez, M. A.; Rodriguez-Villafuerte, M.; Diaz-Perches, R.; Perez-Pastenes, M. A.

2001-01-01

The measurement of stereotactic radiosurgery dose distributions requires an integrating, high-resolution dosimeter capable of providing a spatial map of absorbed dose. This paper describes the use of a commercial radiochromic dye film (GafChromic MD-55-2) to measure radiosurgery dose distributions with 6 MV X-rays in a head phantom. The response of the MD-55-2 was evaluated by digitizing and analyzing the films with conventional computer systems. Radiosurgery dose distributions were measured using the radiochromic film in a spherical acrylic phantom of 16 cm diameter undergoing a typical SRS treatment as a patient, and were compared with dose distributions provided by the treatment planning system. The comparison lead to mean radial differences of ±0.6 mm, ±0.9 mm, ±1.3 mm, ±1.9 mm, and ±2.8 mm, for the 80, 60, 50, 40, and 30% isodose curves, respectively. It is concluded that the radiochromic film is a convenient and useful tool for radiosurgery treatment planning validation

CyberKnife radiosurgery: Precision without incision

Directory of Open Access Journals (Sweden)

Enja Siva Prasad Reddy

2015-01-01

Full Text Available CyberKnife stereotactic radiosurgery system is an innovative, effective, frameless, non-invasive substitute for conventional surgical treatment of cancer. It works on the principle of stereotaxy. It is used for the treatment of both cancerous and non-cancerous tumors, intracranial lesions, tumors of lung, spine, prostate, and kidney, recurrent cases of oral squamous cell carcinoma, arteriovenous malformation, and trigeminal neuralgia. It has an advantage over other systems like Gamma knife radiosurgery and linear accelerator (LINAC-based systems, as it is frameless, has submillimeter accuracy, does not affect the normal cells adjacent to the lesion, and tracks the lesion in synchronization with the patient′s respiratory rate. The future of CyberKnife encompasses possibilities such as incremental improvements in accuracy and better shaping of the field of radiation and would certainly allow extension of radiosurgery as an effective substitute for chemotherapy. This paper aims to review and highlight the immense potential that CyberKnife holds in the field of dentistry in treating disorders of the head and neck region, thereby ensuring enhanced longevity for the patients.

WE-A-304-00: Stereotactic Radiosurgery

International Nuclear Information System (INIS)

2015-01-01

The high fractional doses, stringent requirements for accuracy and precision, and surgical perspective characteristic of intracranial radiosurgery create considerations for treatment planning which are distinct from most other radiotherapy procedures. This session will introduce treatment planning techniques specific to two popular intracranial SRS modalities: Gamma Knife and MLC-based Linac. The basic treatment delivery characteristics of each device will be reviewed with a focus on how those characteristics determine the paradigm used for treatment planning. Basic techniques for treatment planning will be discussed, including considerations such as isodose selection, target and organ-at-risk definition, quality indices, and protection of critical structures. Future directions for SRS treatment planning will also be discussed. Learning Objectives: Introduce the basic physical principles of intracranial radiosurgery and how they are realized in the treatment planning paradigms for Gamma Knife and Linac radiosurgery. Demonstrate basic treatment planning techniques. Discuss metrics for evaluating SRS treatment plan quality. Discuss recent and future advances in SRS treatment planning. D. Schlesinger receives research support from Elekta, AB

WE-A-304-00: Stereotactic Radiosurgery

Energy Technology Data Exchange (ETDEWEB)

NONE

2015-06-15

The high fractional doses, stringent requirements for accuracy and precision, and surgical perspective characteristic of intracranial radiosurgery create considerations for treatment planning which are distinct from most other radiotherapy procedures. This session will introduce treatment planning techniques specific to two popular intracranial SRS modalities: Gamma Knife and MLC-based Linac. The basic treatment delivery characteristics of each device will be reviewed with a focus on how those characteristics determine the paradigm used for treatment planning. Basic techniques for treatment planning will be discussed, including considerations such as isodose selection, target and organ-at-risk definition, quality indices, and protection of critical structures. Future directions for SRS treatment planning will also be discussed. Learning Objectives: Introduce the basic physical principles of intracranial radiosurgery and how they are realized in the treatment planning paradigms for Gamma Knife and Linac radiosurgery. Demonstrate basic treatment planning techniques. Discuss metrics for evaluating SRS treatment plan quality. Discuss recent and future advances in SRS treatment planning. D. Schlesinger receives research support from Elekta, AB.

Factors Determining the Clinical Complications of Radiosurgery for AVM.

Science.gov (United States)

Machnowska, Matylda; Taeshineetanakul, Patamintita; Geibprasert, Sasikhan; Menezes, Ravi; Agid, Ronit; Terbrugge, Karel G; Andrade-Souza, Yuri; Schwartz, Michael L; Krings, Timo

2013-11-01

To identify the predictors of symptomatic post-radiation T2 signal change in patients with arteriovenous malformations (AVM) treated with radiosurgery. The charts of 211 consecutive patients with arteriovenous malformations treated with either gamma knife radisurgery or linear accelerator radiosurgery between 2000-2009 were retrospectively reviewed. 168 patients had a minimum of 12 months of clinical and radiologic follow-up following the procedure and complete dosage data. Pretreatment characteristics and dosimetric variables were analyzed to identify predictors of adverse radiation effects. 141 patients had no clinical symptomatic complications. 21 patients had global or focal neurological deficits attributed to symptomatic edema. Variables associated with development of symptomatic edema included a non-hemorrhagic symptomatic presentation compared to presentation with hemorrhage, p=0.001; OR (95%CI) = 6.26 (1.99, 19.69); the presence of venous rerouting compared to the lack of venous rerouting, p=0.031; OR (95% CI) = 3.25 (1.20, 8.80); radiosurgery with GKS compared to linear accelerator radiosurgery p = 0.012; OR (95% CI) = 4.58 (1.28, 16.32); and the presence of more than one draining vein compared to a single draining vein p = 0.032; OR (95% CI) = 2.82 (1.06, 7.50). We postulated that the higher maximal doses used with gamma knife radiosurgery may be responsible for the greater number of adverse radiation effects with this modality compared to linear accelerator radiosurgery. We found that AVMs with greater venous complexity and therefore instability resulted in more adverse treatment outcomes, suggesting that AVM angioarchitecture should be considered when making treatment decisions. Facteurs en cause dans les complications cliniques de la radiochirurgie pour une malformation artérioveineuse.

The rationale and technique of staged-volume arteriovenous malformation radiosurgery

International Nuclear Information System (INIS)

Pollock, Bruce E.; Kline, Robert W.; Stafford, Scott L.; Foote, Robert L.; Schomberg, Paula J.

2000-01-01

Purpose: Stereotactic radiosurgery is an effective management strategy for properly selected arteriovenous malformation (AVM) patients. However, the risk of postradiosurgical radiation-related injury generally limits this procedure to patients with AVMs of an average diameter of 3 cm or less. Radiosurgery of large AVMs in a planned staged fashion was undertaken to limit the radiation exposure to the surrounding normal brain. Methods and Materials: Between April 1997 and December 1999, 10 patients with a median AVM volume of 17.4 cm 3 (range, 7.4-53.3 cm 3 ) underwent staged-volume radiosurgery (23 procedures). At the first radiosurgical procedure, the total volume of the AVM is estimated and a dose plan calculated that covers 10 cm 3 -15 cm 3 , or one-half the nidus volume if the AVM is critically located (brainstem, thalamus, or basal ganglia). At 6-month intervals thereafter, radiosurgery was repeated to different portions of the AVM with the previous dose plan(s) being re-created utilizing intracranial landmarks to minimize radiation overlap. Radiosurgical procedures were continued until the entire malformation has been irradiated. Results: The radiation dosimetry of staged-volume AVM radiosurgery was compared to hypothetical single-session procedures for the 10 patients. Staged-volume radiosurgery decreased the 12-Gy volume by an average of 11.1% (range, 4.9-21%) (p < 0.001). The non-AVM 12-Gy volume was reduced by an average of 27.2% (range, 12.5-51.3%) (p < 0.001). Discussion: Staged-volume radiosurgery of large AVMs results in less radiation exposure to the adjacent brain. Further follow-up is needed to determine whether this technique provides a high rate of AVM obliteration while maintaining an acceptable rate of radiation-related complications

Multileaf collimator-based linear accelerator radiosurgery: five-year efficiency analysis.

Science.gov (United States)

Lawson, Joshua D; Fox, Tim; Waller, Anthony F; Davis, Lawrence; Crocker, Ian

2009-03-01

In 1989, Emory University initiated a linear accelerator (linac) radiosurgery program using circular collimators. In 2001, the program converted to a multileaf collimator. Since then, the treatment parameters of each patient have been stored in the record-and-verify system. Three major changes have occurred in the radiosurgery program in the past 6 years: in 2002, treatment was changed from static conformal beams to dynamic conformal arc (DCA) therapy, and all patients were imaged before treatment. Beginning in 2005, a linac was used, with the opportunity to treat at higher dose rates (600-1,000 monitor units/min). The aim of this study was to analyze the time required to deliver radiosurgery and the factors affecting treatment delivery. Benchmark data are provided for centers contemplating initiating linac radiosurgery programs. Custom software was developed to mine the record-and-verify system database and automatically perform a chart review on patients who underwent stereotactic radiosurgery from March 2001 to October 2006. The software extracted 510 patients who underwent stereotactic radiosurgery, and the following information was recorded for each patient: treatment technique, treatment time (from initiation of imaging, if done, to completion of therapy), number of isocenters, number of fields, total monitor units, and dose rate. Of the 510 patients, 395 were treated with DCA therapy and 115 with static conformal beams. The average number of isocenters treated was 1.06 (range, 1-4). The average times to deliver treatment were 24.1 minutes for patients who underwent DCA therapy and 19.3 minutes for those treated with static conformal beams, reflecting the lack of imaging in the latter patients. Eighty percent of patients were treated in question the need for a dedicated radiosurgery unit for even busy treatment centers.

Gamma knife radiosurgery in movement disorders: Indications and limitations.

Science.gov (United States)

Higuchi, Yoshinori; Matsuda, Shinji; Serizawa, Toru

2017-01-01

Functional radiosurgery has advanced steadily during the past half century since the development of the gamma knife technique for treating intractable cancer pain. Applications of radiosurgery for intracranial diseases have increased with a focus on understanding radiobiology. Currently, the use of gamma knife radiosurgery to ablate deep brain structures is not widespread because visualization of the functional targets remains difficult despite the increased availability of advanced neuroimaging technology. Moreover, most existing reports have a small sample size or are retrospective. However, increased experience with intraoperative neurophysiological evaluations in radiofrequency thalamotomy and deep brain stimulation supports anatomical and neurophysiological approaches to the ventralis intermedius nucleus. Two recent prospective studies have promoted the clinical application of functional radiosurgery for movement disorders. For example, unilateral gamma knife thalamotomy is a potential alternative to radiofrequency thalamotomy and deep brain stimulation techniques for intractable tremor patients with contraindications for surgery. Despite the promising efficacy of gamma knife thalamotomy, however, these studies did not include sufficient follow-up to confirm long-term effects. Herein, we review the radiobiology literature, various techniques, and the treatment efficacy of gamma knife radiosurgery for patients with movement disorders. Future research should focus on randomized controlled studies and long-term effects. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

International Spine Radiosurgery Consortium Consensus Guidelines for Target Volume Definition in Spinal Stereotactic Radiosurgery

International Nuclear Information System (INIS)

Cox, Brett W.; Spratt, Daniel E.; Lovelock, Michael; Bilsky, Mark H.; Lis, Eric; Ryu, Samuel; Sheehan, Jason; Gerszten, Peter C.; Chang, Eric; Gibbs, Iris; Soltys, Scott; Sahgal, Arjun; Deasy, Joe; Flickinger, John; Quader, Mubina; Mindea, Stefan

2012-01-01

Purpose: Spinal stereotactic radiosurgery (SRS) is increasingly used to manage spinal metastases. However, target volume definition varies considerably and no consensus target volume guidelines exist. This study proposes consensus target volume definitions using common scenarios in metastatic spine radiosurgery. Methods and Materials: Seven radiation oncologists and 3 neurological surgeons with spinal radiosurgery expertise independently contoured target and critical normal structures for 10 cases representing common scenarios in metastatic spine radiosurgery. Each set of volumes was imported into the Computational Environment for Radiotherapy Research. Quantitative analysis was performed using an expectation maximization algorithm for Simultaneous Truth and Performance Level Estimation (STAPLE) with kappa statistics calculating agreement between physicians. Optimized confidence level consensus contours were identified using histogram agreement analysis and characterized to create target volume definition guidelines. Results: Mean STAPLE agreement sensitivity and specificity was 0.76 (range, 0.67-0.84) and 0.97 (range, 0.94-0.99), respectively, for gross tumor volume (GTV) and 0.79 (range, 0.66-0.91) and 0.96 (range, 0.92-0.98), respectively, for clinical target volume (CTV). Mean kappa agreement was 0.65 (range, 0.54-0.79) for GTV and 0.64 (range, 0.54-0.82) for CTV (P<.01 for GTV and CTV in all cases). STAPLE histogram agreement analysis identified optimal consensus contours (80% confidence limit). Consensus recommendations include that the CTV should include abnormal marrow signal suspicious for microscopic invasion and an adjacent normal bony expansion to account for subclinical tumor spread in the marrow space. No epidural CTV expansion is recommended without epidural disease, and circumferential CTVs encircling the cord should be used only when the vertebral body, bilateral pedicles/lamina, and spinous process are all involved or there is extensive metastatic

Stereotactic radiosurgery: basic concepts and current status

International Nuclear Information System (INIS)

Gaur, Maheep Singh

2016-01-01

Term Stereotactic Radiosurgery was coined by Prof Lars Leksell in 1951 as concept. Leksell's experimented together with the radiobiologist Borje Larsson in Uppsala, on trying to develop 'stereotactic radiosurgery', aimed at lesioning in the central brain in functional operations such as thalamotomy and capsulotomy. Clinical experiments using a proton beam were initiated at the Gustav Werner Institute in Uppsala, and a few patients had been treated. Experiences from these led Leksell to design a multi-source 'beam knife', which became ready for use in 1967 as the first 'Gamma Knife' and installed at the private hospital Sophiahammet in Stockholm as a clinical research unit. Moving from functional neurosurgery today Gamma knife is used for a wide range on brain tumors, vascular malformations and functional disorders. Introduction of newer technology in navigation and radiation delivery has made it possible to do whole body Radiosurgery. Various technologies, basic principles, radiobiological aspects and applications will be discussed. (author)

Stereotactic radiosurgery in the palliative treatment of brain metastases

International Nuclear Information System (INIS)

Faria, Sergio L.; Souhami, Luis; Bahary, Jean-Paul; Clark, Brenda; Adamson, Nelson; Podgorsak, Ervin B.; Caron, Jean-Louis; Villemure, Jean-Guy; Olivier, Andre

1995-01-01

Between October, 1988 and November, 1993, 57 patients with metastatic brain disease underwent stereotactic radiosurgery at McGill University, canada. Four patients were excluded from this analysis leaving a total of 53 evaluable patients (with 57 lesions). Radiosurgery was performed with the dynamic rotation technique which uses an isocentric, 10 MV, linear accelerator. A median dose of 1,800 c Gy was given in a single session. In 89% of the cases radiosurgery was used after failure to conventional brain radiotherapy. With a median follow-up of 6 months, the response rate was 65% . Treatments were well tolerated and only 4 patients (7%) developed late complications related to the therapy, with one patient requiring a surgical resection of an area of radionecrose. Radiosurgery appears to be and effective and safe treatment for selected patients with metastatic brain disease, recurrent post-conventional radiotherapy. Its value as a single treatment modality for patients with isolated brain metastasis is now being studied in prospective trials. (author). 29 refs., 4 figs., 4 tabs

Radiosurgery without whole brain radiotherapy in melanoma brain metastases

International Nuclear Information System (INIS)

Grob, J.J.; Regis, J.; Laurans, R.; Delaunay, M.; Wolkenstein, P.; Paul, K.; Souteyrand, P.; Koeppel, M.C.; Murraciole, X.; Perragut, J.C.; Bonerandi, J.J.

1998-01-01

To evaluate the effectiveness of radiosurgery without whole brain radiotherapy in the palliative treatment of melanoma brain metastases, we retrospectively assessed the results in 35 patients: 4 with a solitary brain metastasis, 13 with a single brain metastasis and metastases elsewhere and 18 with multiple brain metastases. The local control rate was 98.2% (55/56 metastases) at 3 months. Median survival was 22 months in patients with a solitary brain metastasis, 7.5 months in patients with a single brain metastasis and metastases elsewhere, and 4 months in patients with multiple brain metastases. Complications were unusual and surgery was required in 2 of 35 patients. These results show for the first time that melanoma patients with a unique brain metastasis with or without metastases elsewhere clearly benefit from tumour control easily obtained by radiosurgery. Although the comparison of radiosurgery with surgery and/or whole brain radiotherapy cannot be adequately addressed, radiosurgery alone seems to provide similar results with lower morbidity and impact on quality of life. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

A comparison of arc-based and static mini-multileaf collimator-based radiosurgery treatment plans

International Nuclear Information System (INIS)

Kubo, Hideo Dale; Pappas, Conrad T.E.; Wilder, Richard B.

1997-01-01

Background: The purpose of this study is to compare arc-based and mini-multileaf collimator (mMLC)-based radiosurgery treatment plans using isodose distributions and dose-volume histograms. Methods: Of 11 patients who underwent conventional arc-based radiosurgery for intracranial malignancies, four were treated with one isocenter, four were treated with two isocenters and three were treated with three isocenters. The same cases were re-planned using a test version of mMLC-based radiosurgery software for multiple static non-coplanar fields. Results and conclusion: For non-spherical targets, treatment planning is relatively intuitive with mMLC-based radiosurgery, reducing the amount of time required for planning. Moreover, a lower dose of radiation is delivered to normal tissue with mMLC-based radiosurgery than with arc-based radiosurgery, which theoretically should lead to a reduced risk of complications

Long-term effects of gamma knife radiosurgery for pediatric craniopharyngioma

International Nuclear Information System (INIS)

Osuka, Koji; Kobayashi, Tatsuya; Kida, Yoshihisa; Tanaka, Takayuki; Yoshida, Kazuo; Hasegawa, Toshinori

2001-01-01

Twenty-one pediatric patients with craniopharyngioma have undergone gamma knife radiosurgery at our facility since May 1991, and we have followed up 10 of these patients for at least 24 months (mean 44.5 months). The patients' ages ranged from 6 to 12 years (mean 8.6 years). Initial presentations were headache in 7 patients, decreased visual acuity in 8, visual field deficit in 5, hypopituitarism in 7, and diabetes insipidus in 3. Prior to radiosurgery, surgical procedures had been performed in 8 patients, conventional radiotherapy in 1, and chemotherapy in 1. Mean tumor diameter was 17.4 mm, and treatment was by gamma knife, with mean maximum and marginal doses of 25.4 Gy and 13.3 Gy, respectively. Follow-up MRI revealed good tumor control (partial response+complete response) in 7 of the 10 patients, with neither further neurological nor endocrinological deterioration. Two patients showed tumor shrinkage for 60 months and 46 months, respectively, after radiosurgery, while, thereafter, tumor gradually recurred at the side of the optic nerve. In one patient, rapid growth of the cyst was observed 6 months after radiosurgery. Gamma knife radiosurgery for pediatric craniopharyngioma is considered to be a safe and effective treatment after microsurgical tumor removal. In cases in which total removal is impossible, it is important to detach the tumor from the optic nerve and to reduce the tumor volume for gamma knife radiosurgery after microsurgery. If the tumor has a cystic component, this should be removed at the time of surgery. (author)

Long-term effects of gamma knife radiosurgery for pediatric craniopharyngioma

Energy Technology Data Exchange (ETDEWEB)

Osuka, Koji; Kobayashi, Tatsuya; Kida, Yoshihisa; Tanaka, Takayuki; Yoshida, Kazuo; Hasegawa, Toshinori [Komaki City Hospital, Aichi (Japan)

2001-02-01

Twenty-one pediatric patients with craniopharyngioma have undergone gamma knife radiosurgery at our facility since May 1991, and we have followed up 10 of these patients for at least 24 months (mean 44.5 months). The patients' ages ranged from 6 to 12 years (mean 8.6 years). Initial presentations were headache in 7 patients, decreased visual acuity in 8, visual field deficit in 5, hypopituitarism in 7, and diabetes insipidus in 3. Prior to radiosurgery, surgical procedures had been performed in 8 patients, conventional radiotherapy in 1, and chemotherapy in 1. Mean tumor diameter was 17.4 mm, and treatment was by gamma knife, with mean maximum and marginal doses of 25.4 Gy and 13.3 Gy, respectively. Follow-up MRI revealed good tumor control (partial response+complete response) in 7 of the 10 patients, with neither further neurological nor endocrinological deterioration. Two patients showed tumor shrinkage for 60 months and 46 months, respectively, after radiosurgery, while, thereafter, tumor gradually recurred at the side of the optic nerve. In one patient, rapid growth of the cyst was observed 6 months after radiosurgery. Gamma knife radiosurgery for pediatric craniopharyngioma is considered to be a safe and effective treatment after microsurgical tumor removal. In cases in which total removal is impossible, it is important to detach the tumor from the optic nerve and to reduce the tumor volume for gamma knife radiosurgery after microsurgery. If the tumor has a cystic component, this should be removed at the time of surgery. (author)

Linac radiosurgery for high-grade gliomas: the University of Florida experience

Energy Technology Data Exchange (ETDEWEB)

Buatti, John M; Friedman, William A; Bova, Frank J; Mendenhall, William M

1995-04-30

Purpose: Stereotactic radiosurgery has been reported as a promising boost technique for the treatment of selected patients with high-grade glioma. The first 11 patients given this treatment at the University of Florida are reported. Methods and Materials: Six patients with glioblastoma multiforme and five with anaplastic astrocytoma were carefully selected for treatment with linac radiosurgery. All patients had a Karnofsky performance status {>=} 90%. Median age of patients was 42.1 years. External-beam radiotherapy delivered a median dose of 60 Gy. Stereotactic radiosurgery was delivered to the enhancing tumor volume without margin. Median treatment volume was 14 cm{sup 3} (equivalent sphere diameter, 3 cm). The maximum volume of any tumor treated was 22.5 cm{sup 3} (equivalent sphere diameter, 3.5 cm). Median stereotactic radiosurgery boost dose was 12.5 Gy, and median prescription sphere was the 80% isodose shell. Results: Despite rigorous selection and aggressive stereotactic boost irradiation, this patient cohort had a median actuarial survival of 17 months. All patients have had progression of intracranial disease within 1 year of radiosurgery, and only 3 of 11 remain alive with a median follow-up of 13 months. Conclusion: These results differ significantly from others reported. Comparative analysis suggests tumor volume may be an important prognostic factor in patients treated with stereotactic radiosurgery. Future studies need to define appropriate patient cohorts for the boost technique.

The history of stereotactic radiosurgery and radiotherapy.

Science.gov (United States)

Lasak, John M; Gorecki, John P

2009-08-01

Stereotactic neurosurgery originated from the pioneering work of Horsley and Clarke, who developed a stereotactic apparatus to study the monkey brain in 1908. Spiegel and Wycis applied this technology to the human brain in 1947, which ultimately lead to the development of multiple stereotactic neurosurgical devices during the 1950s. It was Lars Leksell of Sweden, however, who envisioned stereotactic radiosurgery. Leksell developed the gamma knife to treat intracranial lesions in a noninvasive fashion. His work stimulated worldwide interest and created the field of stereotactic radiosurgery.

Radiosurgery for acoustic neurinomas: Early experience

International Nuclear Information System (INIS)

Linskey, M.E.; Lunsford, L.D.; Flickinger, J.C.

1990-01-01

We reviewed our early experience with the first 26 patients with acoustic neurinomas (21 unilateral, 5 bilateral) treated by stereotactic radiosurgery using the first North American 201-source cobalt-60 gamma knife. Follow-up ranged from 6 to 19 months (median, 13 months). Serial postoperative imaging showed either a decrease in tumor size (11 patients) or growth arrest (15 patients). Loss of central contrast enhancement was a characteristic change (18 patients). Seven patients had good or serviceable hearing preoperatively. In all 7 the preoperative hearing status was retained immediately after radiosurgery. At follow-up, 3 had preserved hearing, 1 had reduced hearing, and 3 had lost all hearing in the treated ear. Hearing in 1 patient that was nonserviceable preoperatively later improved to a serviceable hearing level. Delayed facial paresis developed in 6 patients, and delayed trigeminal sensory loss developed in 7 patients, none of whom had significant deficits before radiosurgery. Both facial and trigeminal deficits tended to improve within 3 to 6 months of onset with excellent recovery anticipated. Lower cranial nerve dysfunction was not observed. All 26 patients remain at their preoperative employment or functional status. At present, stereotactic radiosurgery is an alternative treatment for acoustic neurinomas in patients who are elderly, have significant concomitant medical problems, have a tumor in their only hearing ear, have bilateral acoustic neurinomas, refuse microsurgical excision, or have recurrent tumor despite surgical resection. Although longer and more extensive follow-up is required, the control of tumor growth and the acceptable rate of complications in this early experience testifies to the future expanding role of this technique in the management of selected acoustic neurinomas

Geometrically based optimization for extracranial radiosurgery

International Nuclear Information System (INIS)

Liu Ruiguo; Wagner, Thomas H; Buatti, John M; Modrick, Joseph; Dill, John; Meeks, Sanford L

2004-01-01

For static beam conformal intracranial radiosurgery, geometry of the beam arrangement dominates overall dose distribution. Maximizing beam separation in three dimensions decreases beam overlap, thus maximizing dose conformality and gradient outside of the target volume. Webb proposed arrangements of isotropically convergent beams that could be used as the starting point for a radiotherapy optimization process. We have developed an extracranial radiosurgery optimization method by extending Webb's isotropic beam arrangements to deliverable beam arrangements. This method uses an arrangement of N maximally separated converging vectors within the space available for beam delivery. Each bouquet of isotropic beam vectors is generated by a random sampling process that iteratively maximizes beam separation. Next, beam arrangement is optimized for critical structure avoidance while maintaining minimal overlap between beam entrance and exit pathways. This geometrically optimized beam set can then be used as a template for either conformal beam or intensity modulated extracranial radiosurgery. Preliminary results suggest that using this technique with conformal beam planning provides high plan conformality, a steep dose gradient outside of the tumour volume and acceptable critical structure avoidance in the majority of clinical cases

Gamma knife radiosurgery for endocrine-inactive pituitary adenomas

International Nuclear Information System (INIS)

Liscak, R.; Vladyka, V.; Simonova, G.; Marek, J.; Vymazal, J.

2007-01-01

The goal of nonsecreting pituitary adenoma radiosurgery is to halt tumor growth and to maintain normal performance of the hypophysis and the functionally important structures around the sella. The effectiveness of gamma knife radiosurgery was evaluated. Over a period of 10 years (1993-2003), 140 patients with nonsecreting pituitary adenoma were treated by Leksell gamma knife at our Centre. Seventy-nine of them were followed up for longer than 3 years. Their age range was 24-73 years, with a median of 54 years. Eighty-five percent of them had previous open surgery. Fifteen patients had adenoma contact with the optic tract. Fourteen patients had a normally functioning hypophysis, 48 patients had complete panhypopituitarism, while the rest retained partial functions of the normal hypophysis. Adenoma volumes ranged between 0.1 and 31.3, the median being 3.45 ccm. The marginal dose ranged between 12 and -35 Gy, with a median of 20 Gy. The follow-up ranged from 36 to 122 months, with a median of 60 months. No adenoma growth was detected; 89 % of treated adenomas decreased in size, with a median volume reduction of 61 %. There was no perimeter vision impairment after radiosurgery, while 4 out of 52 patients with abnormal perimeter vision reported improvement. There was no impairment of oculomotor nerve function. Impairment of hypophysis function was observed in 2 patients. Radiosurgery has a reliable antiproliferative effect on nonsecreting pituitary adenomas. It is a safe treatment with a low risk of morbidity. Short contact between a nonsecreting pituitary adenoma and the optic pathway is not an absolute contraindication for Gamma knife radiosurgery. (author)

A simulation and training environment for robotic radiosurgery

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Schlaefer, Alexander [University of Luebeck, Institute for Robotics and Cognitive Systems, Luebeck (Germany); Stanford University, Department of Radiation Oncology, Stanford, CA (United States); Gill, Jakub; Schweikard, Achim [University of Luebeck, Institute for Robotics and Cognitive Systems, Luebeck (Germany)

2008-09-15

To provide a software environment for simulation of robotic radiosurgery, particularly to study the effective robot workspace with respect to the treatment plan quality, and to illustrate the concepts of robotic radiosurgery. A simulation environment for a robotic radiosurgery system was developed using Java and Java3D. The kinematics and the beam characteristics were modeled and linked to a treatment planning module. Simulations of different robot workspace parameters for two example radiosurgical patient cases were performed using the novel software tool. The first case was an intracranial lesion near the left inner ear, the second case was a spinal lesion. The planning parameters for both cases were visualized with the novel simulation environment. An incremental extension of the robot workspace had limited effect for the intracranial case, where the original workspace already covered the left side of the patient. For the spinal case, a larger workspace resulted in a noticeable improvement in plan quality and a large portion of the beams being delivered from the extended workspace. The new software environment is useful to simulate and analyze parameters and configurations for robotic radiosurgery. An enlarged robot workspace may result in improved plan quality depending on the location of the target region. (orig.)

A simulation and training environment for robotic radiosurgery

International Nuclear Information System (INIS)

Schlaefer, Alexander; Gill, Jakub; Schweikard, Achim

2008-01-01

To provide a software environment for simulation of robotic radiosurgery, particularly to study the effective robot workspace with respect to the treatment plan quality, and to illustrate the concepts of robotic radiosurgery. A simulation environment for a robotic radiosurgery system was developed using Java and Java3D. The kinematics and the beam characteristics were modeled and linked to a treatment planning module. Simulations of different robot workspace parameters for two example radiosurgical patient cases were performed using the novel software tool. The first case was an intracranial lesion near the left inner ear, the second case was a spinal lesion. The planning parameters for both cases were visualized with the novel simulation environment. An incremental extension of the robot workspace had limited effect for the intracranial case, where the original workspace already covered the left side of the patient. For the spinal case, a larger workspace resulted in a noticeable improvement in plan quality and a large portion of the beams being delivered from the extended workspace. The new software environment is useful to simulate and analyze parameters and configurations for robotic radiosurgery. An enlarged robot workspace may result in improved plan quality depending on the location of the target region. (orig.)

Seizure control of Gamma Knife radiosurgery for non-hemorrhagic arteriovenous malformations

International Nuclear Information System (INIS)

Lim, Y.J.; Lee, C.Y.; Koh, J.S.; Kim, T.S.; Kim, G.K.; Rhee, B.A.

2006-01-01

Although radiosurgery has been found to be a safe and effective alternative treatment, seizure outcome of arteriovenous malformation (AVM) radiosurgery has not been documented in detail. We report the effect of Gamma Knife radiosurgery (GKRS) on seizures associated with AVMs and discuss the various factors that influence the prognosis. Between 1992 and 2001 246 patients were treated with GKRS for AVMs at Kyung-Hee medical center. Forty five (17.0 %) patients have non-hemorrhagic AVMs and presenting symptom was seizure. Two patients of all were excluded from this study due to loss of follow-up after radiosurgery. In this study retrospective analysis of clinical characteristics, radiological findings, radiosurgical seizure outcome were performed. There were 32 male and 11 female with age ranging from 10 to 74 years (mean 35 years). Type of seizure included: general tonic clonic (n = 28); focal motor or sensory (n = 7): partial complex (n = 8). The location of AVM was temporal (n = 18); frontal (n = 9): deep seated (n =7): parietal (n = 5); occipital (n = 4). Follow-up period was from 8 months to 12 years (mean 46 months). Mean volume was 6.2 cc (2.7-20), mean marginal and maximal dosage was 19.5 (17-26) and 36.6 Gy (13-50). During follow-up after radiosurgical treatment, 23 (53.5 %) of 43 patients were seizure-free. 10 (23.3 %) had significant improvement, were unchanged in 8 (18.6 %) and aggravated in 2 (4.6 %) patients. In 33 patients, follow-up angiography or MRI was performed. Complete obliteration was achieved in 16 (49.0 %) patients, partial obliteration in 13 (39.0 %). Four were unchanged (12.0 %). Of 33 patients with follow-up performed, 26 were followed for over 2 years. Eleven (84.6 %) of 13 patients with complete obliteration were seizure-free (p < 0.005). Four (36.3 %) of 13 with partial obliteration and unchanged remained seizure-free. Fifteen patients had experienced intractable seizure before radiosurgery. After radiosurgery, seizures disappeared in 8

The treatment for acoustic neuromas. Indication and results of gamma knife radiosurgery and surgery

International Nuclear Information System (INIS)

Iwai, Yoshiyasu; Yamanaka, Kazuhiro; Uyama, Taichi; Morikawa, Toshie; Honda, Yuji; Matsusaka, Yasuhiro; Komiyama, Masaki; Yasui, Toshihiro

2004-01-01

We evaluated the treatment results of acoustic neuromas in the era of radiosurgery. We treated acoustic neuromas using the following strategy. Small to medium size tumors (below 3 cm) were treated by gamma knife radiosurgery and large tumors (above 3 cm) were treated using a combination of surgery and radiosurgery. Using gamma knife radiosurgery we were able to achieve 96.4% of clinical tumor growth control with 0.7% incidence of trigeminal neuropathy (without new facial neuropathy). We used low dose radiosurgery (average tumor marginal dose 11.8 Gy) with a follow-up of an average of 54 months. For the 17 patients with large tumors treated by the combination of surgery and radiosurgery who could be followed up for over 24 months after radiosurgery, we were able to preserve normal facial function (House-Brackmann grade I-II) in 70.6% of the patients after subtotal removal. High clinical tumor growth control for residual tumor was achieved in 94.1% of subjects with an average of 40 months follow-up. By using this strategy, the treatment outcome for acoustic neuroma is improved from the standpoint of functional outcome and maintaining the patient's quality of life. (author)

Tumour response and morphological changes of acoustic neurinomas after radiosurgery

International Nuclear Information System (INIS)

Valentino, V.; Raimondi, A.J.

1995-01-01

Twenty-seven of the 1560 patients treated by radiosurgery during the period 1984-1993 had acoustic neurinomas. Four cases were excluded from this study because they had a follow-up of less than 2 years. There were 24 neurinomas treated in 23 patients as one patient had a bilateral tumour. Seven patients underwent radiosurgery for a recurrent tumour (already operated on once or twice), while it was the first treatment for 16 patients. The tumour volume ranged from 1.99 cm 3 to 18.30 cm 3 , and the patient follow-up was from 2 to 8 years. To determine the target on CT/NMR for linear accelerator stereotactic irradiation, the Greitz-Bergstroem non-invasive head fixation device was used. It was again adopted for subsequent serial imaging, and for repeat radiosurgery when necessary. The total peripheral tumour dose ranged from 12 to 45 Gy. In 9 patients there was a reduction in tumour volume varying from 39 to 100% , while 14 of the neurinomas appeared stable after an average follow-up of 3 years. In one patient there was an increase in size of the tumour. Variable morphological changes were present in 66% of the neurinomas treated. Radiosurgery is indicated as an alternative to microsurgery for inoperab1e patients and for those who refuse surgery, for recurrent tumours, and as a post-operative complementary treatment for partially removed tumours. A gradual approach to radiosurgery, depending on tumour response, allows a greater efficacy with minimal risk. In the present series no complications were observed. Hearing was preserved at almost the same level as that prior to radiosurgery in all patients. (author)

Dose conformity of gamma knife radiosurgery and risk factors for complications

International Nuclear Information System (INIS)

Nakamura, Jean L.; Verhey, Lynn J.; Smith, Vernon; Petti, Paula L.; Lamborn, Kathleen R.; Larson, David A.; Wara, William M.; McDermott, Michael W.; Sneed, Penny K.

2001-01-01

Purpose: To quantitatively evaluate dose conformity achieved using Gamma Knife radiosurgery, compare results with those reported in the literature, and evaluate risk factors for complications. Methods and Materials: All lesions treated at our institution with Gamma Knife radiosurgery from May 1993 (when volume criteria were routinely recorded) through December 1998 were reviewed. Lesions were excluded from analysis for reasons listed below. Conformity index (the ratio of prescription volume to target volume) was calculated for all evaluable lesions and for lesions comparable to those reported in the literature on conformity of linac radiosurgery. Univariate Cox regression models were used to test for associations between treatment parameters and toxicity. Results: Of 1612 targets treated in 874 patients, 274 were excluded, most commonly for unavailability of individual prescription volume data because two or more lesions were included within the same dose matrix (176 lesions), intentional partial coverage for staged treatment of large arteriovenous malformations (AVMs) (33 lesions), and missing target volume data (26 lesions). The median conformity indices were 1.67 for all 1338 evaluable lesions and 1.40-1.43 for lesions comparable to two linac radiosurgery series that reported conformity indices of 1.8 and 2.7, respectively. Among all 651 patients evaluable for complications, there were one Grade 5, eight Grade 4, and 27 Grade 3 complications. Increased risk of toxicity was associated with larger target volume, maximum lesion diameter, prescription volume, or volume of nontarget tissue within the prescription volume. Conclusions: Gamma Knife radiosurgery achieves much more conformal dose distributions than those reported for conventional linac radiosurgery and somewhat more conformal dose distributions than sophisticated linac radiosurgery techniques. Larger target, nontarget, or prescription volumes are associated with increased risk of toxicity

Stereotactic Radiosurgery versus Natural History in Patients with Growing Vestibular Schwannomas.

Science.gov (United States)

Tu, Albert; Gooderham, Peter; Mick, Paul; Westerberg, Brian; Toyota, Brian; Akagami, Ryojo

2015-08-01

Objective To describe our experience with stereotactic radiosurgery and its efficacy on growing tumors, and then to compare this result with the natural history of a similar cohort of non-radiation-treated lesions. Study Design A retrospective chart review and cohort comparison. Methods The long-term control rates of patients having undergone radiosurgery were collected and calculated, and this population was then compared with a group of untreated patients from the same period of time with growing lesions. Results A total of 61 patients with growing vestibular schwannomas treated with radiosurgery were included. After a mean of 160 months, we observed a control rate of 85.2%. When compared with a group of 36 patients with growing tumors who were yet to receive treatment (previously published), we found a corrected control rate or relative risk reduction of only 76.8%. Conclusion Radiosurgery for growing vestibular schwannomas is less effective than previously reported in unselected series. Although radiosurgery still has a role in managing this disease, consideration should be given to the actual efficacy that may be calculated when the natural history is known. We hope other centers will similarly report their experience on this cohort of patients.

Gamma-knife radiosurgery for metastatic brain tumors from primary lung cancer

International Nuclear Information System (INIS)

Uchiyama, Bine; Satoh, Ken; Saijo, Yasuo

1998-01-01

Forty patients with metastatic brain tumors from primary lung cancer underwent radiosurgery (γ-knife). We retrospectively compared their prior treatment history, number of metastatic foci, and performance status, to evaluate the effects of, and indications for, γ-knife therapy. After both the primary and the metastatic tumors were controlled, performance status could be used as an index in the choice of γ-knife therapy. Our results demonstrate that repeated γ-knife radiosurgeries prolonged survival time. Gamma-knife radiosurgery improves quality of life and prognosis of patients with metastatic brain tumors. (author)

Radiosurgery of craniopharyngiomas. Results of long-term follow-up

International Nuclear Information System (INIS)

Kida, Yoshihisa; Hasegawa, Toshinori; Yoshimoto, Masayuki; Koike, Johzi; Kobayashi, Tatsuya

2007-01-01

Long-term follow-up results of craniopharyngiomas after radiosurgery are reported. Among 125 cases of craniopharyngioma, long-term follow-up more than 6 months is obtained in 108 cases. Majority of the cases have had surgical excision before radiosurgery. The tumors, 19 mm in mean diameter were treated with the mean maximum dose of 22.1 Gy and with the marginal dose of 11.6 Gy. The final radiological outcomes during 63 months of mean follow-up showed 9 complete responses (CRs), 61 partial responses (PRs), 1 minor response (MR), 19 no changes (NCs) and 18 PGs, indicating the response rate of 65% and the control rate of 83% respectively. Neurological and endocrinological signs were improved in 18%, unchanged in 53% and worsened in 15% of cases, meanwhile 8% of the patients were dead. Small and solid tumors were the best indication for radiosurgery due to excellent tumor control as well as no adverse effects. They may have a good chance for complete remission. In conclusion a sufficient tumor resection with microsurgery is required and subsequent radiosurgery is most adequate for treating craniopharyngiomas. (author)

Compensating for Quasi-periodic Motion in Robotic Radiosurgery

CERN Document Server

Ernst, Floris

2012-01-01

Compensating for Quasi-periodic Motion in Robotic Radiosurgery outlines the techniques needed to accurately track and compensate for respiratory and pulsatory motion during robotic radiosurgery. The algorithms presented within the book aid in the treatment of tumors that move during respiration. In Chapters 1 and 2,  the book introduces the concept of stereotactic body radiation therapy, motion compensation strategies and the clinical state-of-the-art. In Chapters 3 through 5, the author describes and evaluates new methods for motion prediction, for correlating external motion to internal organ motion, and for the evaluation of these algorithms’ output based on an unprecedented amount of real clinical data. Finally, Chapter 6 provides a brief introduction into currently investigated, open questions and further fields of research. Compensating for Quasi-periodic Motion in Robotic Radiosurgery targets researchers working in the related fields of surgical oncology, artificial intelligence, robotics and more. ...

Evaluation of Image-Guided Positioning for Frameless Intracranial Radiosurgery

International Nuclear Information System (INIS)

Lamba, Michael; Breneman, John C.; Warnick, Ronald E.

2009-01-01

Purpose: The standard for target alignment and immobilization in intracranial radiosurgery is frame-based alignment and rigid immobilization using a stereotactic head ring. Recent improvements in image-guidance systems have introduced the possibility of image-guided radiosurgery with nonrigid immobilization. We present data on the alignment accuracy and patient stability of a frameless image-guided system. Methods and Materials: Isocenter alignment errors were measured for in vitro studies in an anthropomorphic phantom for both frame-based stereotactic and frameless image-guided alignment. Subsequently, in vivo studies assessed differences between frame-based and image-guided alignment in patients who underwent frame-based intracranial radiosurgery. Finally, intratreatment target stability was determined by image-guided alignment performed before and after image-guided mask immobilized radiosurgery. Results: In vitro hidden target localization errors were comparable for the framed (0.7 ± 0.5 mm) and image-guided (0.6 ± 0.2 mm) techniques. The in vivo differences in alignment were 0.9 ± 0.5 mm (anteroposterior), -0.2 ± 0.4 mm (superoinferior), and 0.3 ± 0.5 mm (lateral). For in vivo stability tests, the mean distance differed between the pre- and post-treatment positions with mask-immobilized radiosurgery by 0.5 ± 0.3 mm. Conclusion: Frame-based and image-guided alignment accuracy in vitro was comparable for the system tested. In vivo tests showed a consistent trend in the difference of alignment in the anteroposterior direction, possibly due to torque to the ring and mounting system with frame-based localization. The mask system as used appeared adequate for patient immobilization.

Image-guided linear accelerator-based spinal radiosurgery for hemangioblastoma.

Science.gov (United States)

Selch, Michael T; Tenn, Steve; Agazaryan, Nzhde; Lee, Steve P; Gorgulho, Alessandra; De Salles, Antonio A F

2012-01-01

To retrospectively review the efficacy and safety of image-guided linear accelerator-based radiosurgery for spinal hemangioblastomas. Between August 2004 and September 2010, nine patients with 20 hemangioblastomas underwent spinal radiosurgery. Five patients had von Hipple-Lindau disease. Four patients had multiple tumors. Ten tumors were located in the thoracic spine, eight in the cervical spine, and two in the lumbar spine. Tumor volume varied from 0.08 to 14.4 cc (median 0.72 cc). Maximum tumor dimension varied from 2.5 to 24 mm (median 10.5 mm). Radiosurgery was performed with a dedicated 6 MV linear accelerator equipped with a micro-multileaf collimator. Median peripheral tumor dose and prescription isodose were 12 Gy and 90%, respectively. Image guidance was performed by optical tracking of infrared reflectors, fusion of oblique radiographs with dynamically reconstructed digital radiographs, and automatic patient positioning. Follow-up varied from 14 to 86 months (median 51 months). Kaplan-Meier estimated 4-year overall and solid tumor local control rates were 90% and 95%, respectively. One tumor progressed 12 months after treatment and a new cyst developed 10 months after treatment in another tumor. There has been no clinical or imaging evidence for spinal cord injury. Results of this limited experience indicate linear accelerator-based radiosurgery is safe and effective for spinal cord hemangioblastomas. Longer follow-up is necessary to confirm the durability of tumor control, but these initial results imply linear accelerator-based radiosurgery may represent a therapeutic alternative to surgery for selected patients with spinal hemangioblastomas.

Five Fraction Image-Guided Radiosurgery for Primary and Recurrent Meningiomas

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Eric Karl Oermann

2013-08-01

Full Text Available Purpose: Benign tumors that arise from the meninges can be difficult to treat due to their potentially large size and proximity to critical structures such as cranial nerves and sinuses. Single fraction radiosurgery may increase the risk of symptomatic peritumoral edema. In this study, we report our results on the efficacy and safety of five fraction image-guided radiosurgery for benign meningiomas. Materials/Methods: Clinical and radiographic data from 38 patients treated with five fraction radiosurgery were reviewed retrospectively. Mean tumor volume was 3.83mm3 (range, 1.08-20.79 mm3. Radiation was delivered using the CyberKnife, a frameless robotic image-guided radiosurgery system with a median total dose of 25 Gy (range, 25 Gy-35 Gy. Results: The median follow-up was 20 months. Acute toxicity was minimal with eight patients (21% requiring a short course of steroids for headache at the end of treatment. Pre-treatment neurological symptoms were present in 24 patients (63.2%. Post treatment, neurological symptoms resolved completely in 14 patients (58.3%, and were persistent in eight patients (33.3%. There were no local failures, 24 tumors remained stable (64% and 14 regressed (36%. Pre-treatment peritumoral edema was observed in five patients (13.2%. Post-treatment asymptomatic peritumoral edema developed in five additional patients (13.2%. On multivariate analysis, pre-treatment peritumoral edema and location adjacent to a large vein were significant risk factors for radiographic post-treatment edema (p = 0.001 and p = 0.026 respectively. Conclusions: These results suggest that five fraction image-guided radiosurgery is well tolerated with a response rate for neurologic symptoms that is similar to other standard treatment options. Rates of peritumoral edema and new cranial nerve deficits following five fraction radiosurgery were low. Longer follow-up is required to validate the safety and long-term effectiveness of this treatment approach.

SU-F-J-160: Clinical Evaluation of Targeting Accuracy in Radiosurgery Using Tractography

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Juh, R; Han, J; Kim, C; Oh, C [Seoul National University Bundang Hospital, Seongnamsi, GyeonggiDo (Korea, Republic of); Suh, T [The catholic university of Korea, Seoul (Korea, Republic of)

2016-06-15

Purpose: Focal radiosurgery is a common treatment modality for trigeminal neuralgia (TN), a neuropathic facial pain condition. Assessment of treatment effectiveness is primarily clinical, given the paucity of investigational tools to assess trigeminal nerve changes. The efficiency of radiosurgery is related to its highly precise targeting. We assessed clinically the targeting accuracy of radiosurgery with Gamma knife. We hypothesized that trigeminal tractography provides more information than 2D-MR imaging, allowing detection of unique, focal changes in the target area after radiosurgery. Methods: Sixteen TN patients (2 females, 4 males, average age 65.3 years) treated with Gamma Knife radiosurgery, 40 Gy/50% isodose line underwent 1.5Tesla MR trigeminal nerve. Target accuracy was assessed from deviation of the coordinates of the target compared with the center of enhancement on post MRI. Radiation dose delivered at the borders of contrast enhancement was evaluated. Results: The median deviation of the coordinates between the intended target and the center of contrast enhancement was within 1mm. The radiation doses fitting within the borders of the contrast enhancement the target ranged from 37.5 to 40 Gy. Trigeminal tractography accurately detected the radiosurgical target. Radiosurgery resulted in 47% drop in FA values at the target with no significant change in FA outside the target, suggesting that radiosurgery primarily affects myelin. Tractography was more sensitive, since FA changes were detected regardless of trigeminal nerve enhancement. Conclusion: The median deviation found in clinical assessment of gamma knife treatment for TN Is low and compatible with its high rate of efficiency. DTI parameters accurately detect the effects of focal radiosurgery on the trigeminal nerve, serving as an in vivo imaging tool to study TN. This study is a proof of principle for further assessment of DTI parameters to understand the pathophysiology of TN and treatment

Contemporary treatment with radiosurgery for spine metastasis and spinal cord compression in 2015

Energy Technology Data Exchange (ETDEWEB)

Ryu, Sam Uel; Yoon, Han Hah; Stessin, Alexander; Gutman, Fred; Rosiello, Arthur; Davis, Raphael [Stony Brook University, Stony Brook (United States)

2015-03-15

With the progress of image-guided localization, body immobilization system, and computerized delivery of intensity-modulated radiation delivery, it became possible to perform spine radiosurgery. The next question is how to translate the high technology treatment to the clinical application. Clinical trials have been performed to demonstrate the feasibility of spine radiosurgery and efficacy of the treatment in the setting of spine metastasis, leading to the randomized trials by a cooperative group. Radiosurgery has also demonstrated its efficacy to decompress the spinal cord compression in selected group of patients. The experience indicates that spine radiosurgery has a potential to change the clinical practice in the management of spine metastasis and spinal cord compression.

The treatment for asymptomatic meningiomas in the era of radiosurgery

International Nuclear Information System (INIS)

Iwai, Yoshiyasu; Yamanaka, Kazuhiro; Morikawa, Toshie; Ishiguro, Tomoya; Honda, Yuji; Matsusaka, Yasuhiro; Komiyama, Masaki; Yasui, Toshihiro

2003-01-01

We evaluated the treatment results in asymptomatic meningiomas in the era of radiosurgery. We encountered 56 patients with asymptomatic meningiomas from January, 1994 to December, 2001. There were 16 male patients and 40 female patients. The most common location was the cerebral convexity. We performed gamma knife radiosurgery for three patients after diagnosis of cavernous sinus meningiomas. The other patients were followed-up after diagnosis for a mean follow-up period of 30.8 months (5 months to 8 years). Tumor growth was verified in 25 patients (43%) and two patients (3.7%) suffered neurological deficits. Among the tumor growth patients, operative resection was performed in six patients (11%) and gamma knife radiosurgery was performed in four patients (7.5%). The other patients were placed under observation. We decided the treatment strategy paying attention to the tumor location, tumor growth speed, tumor size and operative difficulty. The tumor growth rate was 0.1 cm/year among the patients with tumor growth. It was 0.72 cm/year (0.02 to 1.54 cm/year) in the operative group, 0.3 cm/year (0.04 to 0.76 cm/year) in the gamma knife radiosurgery group and 0.08 cm/year (0.01 to 0.76 cm/year) in the observed group. One patient suffered procedure-related deterioration of paresis after operation. The treatment of asymptomatic meningiomas must be decided depending on their natural history and locations. We recommend early radiosurgery for cavernous sinus meningiomas. (author)

Failure modes and effects analysis (FMEA) for Gamma Knife radiosurgery.

Science.gov (United States)

Xu, Andy Yuanguang; Bhatnagar, Jagdish; Bednarz, Greg; Flickinger, John; Arai, Yoshio; Vacsulka, Jonet; Feng, Wenzheng; Monaco, Edward; Niranjan, Ajay; Lunsford, L Dade; Huq, M Saiful

2017-11-01

Gamma Knife radiosurgery is a highly precise and accurate treatment technique for treating brain diseases with low risk of serious error that nevertheless could potentially be reduced. We applied the AAPM Task Group 100 recommended failure modes and effects analysis (FMEA) tool to develop a risk-based quality management program for Gamma Knife radiosurgery. A team consisting of medical physicists, radiation oncologists, neurosurgeons, radiation safety officers, nurses, operating room technologists, and schedulers at our institution and an external physicist expert on Gamma Knife was formed for the FMEA study. A process tree and a failure mode table were created for the Gamma Knife radiosurgery procedures using the Leksell Gamma Knife Perfexion and 4C units. Three scores for the probability of occurrence (O), the severity (S), and the probability of no detection for failure mode (D) were assigned to each failure mode by 8 professionals on a scale from 1 to 10. An overall risk priority number (RPN) for each failure mode was then calculated from the averaged O, S, and D scores. The coefficient of variation for each O, S, or D score was also calculated. The failure modes identified were prioritized in terms of both the RPN scores and the severity scores. The established process tree for Gamma Knife radiosurgery consists of 10 subprocesses and 53 steps, including a subprocess for frame placement and 11 steps that are directly related to the frame-based nature of the Gamma Knife radiosurgery. Out of the 86 failure modes identified, 40 Gamma Knife specific failure modes were caused by the potential for inappropriate use of the radiosurgery head frame, the imaging fiducial boxes, the Gamma Knife helmets and plugs, the skull definition tools as well as other features of the GammaPlan treatment planning system. The other 46 failure modes are associated with the registration, imaging, image transfer, contouring processes that are common for all external beam radiation therapy

A new treatment method for brain diseases. Stereotactic radiosurgery

International Nuclear Information System (INIS)

Shirato, Hiroki

1994-01-01

This paper deals with stereotactic radiosurgery, a novel medical treatment technique for brain diseases. It is the most sophisticated modality that allows the functional preservation. Recently, CT scan and MRI scan have dramatically changed the diagnostic accuracy of tumor localization in the brain. A device named stereotactic head fixation system makes it possible to localize deep-seated brain diseases with an accuracy of 1-1.5 mm. Using multiple convergent narrow beams of high-energy X-ray, a stereotactic head frame, and a three dimensional computer graphics of CT images, patients with deep-seated nidus can be treated without any complications. Normal tissues would not receive large doses but the center of the nidus is irradiated heavily because of the convergence of X-ray beams. Thus stereotactic radiosurgery is more accurate, effective, and less toxic than conventional radiotherapy and is safer and more effective than surgery for many brain diseases. Small arteriovenous malformation in the brain, which is a fetal disease, and small acoustic neurinomas, in which surgery often causes facial nerve palsy and hearing loss, are presented as good candidates for radiosurgery. For metastatic brain tumors, stereotactic radiosurgery makes such patients free from neurological symptoms, such as difficulty in walking and speaking, in a few days. (N.K.)

Poster - Thur Eve - 50: Planning and delivery accuracy of stereotactic radiosurgery with Tomotherapy as compared to linear-accelerator and robotic based radiosurgery.

Science.gov (United States)

Thakur, V; Soisson, E; Ruo, R; Doucet, R; Parker, W; Seuntjens, J

2012-07-01

This study includes planning and delivery comparison of three stereotactic radiosurgery techniques : Helical Tomotherapy (HT), circular collimator-based Linear-accelerator and robotic-radiosurgery. Plans were generated for two spherical targets of diameter 6 mm and 10 mm contoured at the center of a Lucite phantom, using similar planning constrains. Planning comparison showed that average conformality (0-1best) for Linear-accelerator, robotic-radiosurgery and HT was 1.43, 1.24, and 1.77 and gradient index (less is better) was 2.72, 4.50 and 13.56 respectively. For delivery comparison, plans were delivered to radiochromic film and measured dose was compared with the planned dose. For Linear-accelerator and robotic-radiosurgery more than 99% pixels-passing a gamma criteria of 3% dose difference and 1 mm distance to agreement where as for HT this value was as low as 40% for off-axis targets. Further investigation of the delivery accuracy as a function of the location of the target with in the bore was initiated using small volume A1SL (0.057 cm 3 ) and MicroLion liquid ion chamber (0.0017 cm 3 ). Point dose measurements for targets located at the center and 10 cm away from the center of the bore showed that delivered dose varied by more than 15% for targets placed away from the center of the bore as opposed to at the center. In conclusion, Linear-accelerator and the robotic-radiosurgery techniques showed preferable gradient and conformality. For HT, point dose measurements were significantly lower than predicted by the TPS when the target was positioned away from the isocenter, while they were found to be higher at isocenter. © 2012 American Association of Physicists in Medicine.

IRLED-based patient localization for linac radiosurgery

International Nuclear Information System (INIS)

Meeks, Sanford L.; Bova, Francis J.; Friedman, William A.; Buatti, John M.; Moore, Russell D.; Mendenhall, William M.

1998-01-01

Purpose: Currently, precise stereotactic radiosurgery delivery is possible with the Gamma Knife or floor-stand linear accelerator (linac) systems. Couch-mounted linac radiosurgery systems, while less expensive and more flexible than other radiosurgery delivery systems, have not demonstrated a comparable level of precision. This article reports on the development and testing of an optically guided positioning system designed to improve the precision of patient localization in couch-mounted linac radiosurgery systems. Methods and Materials: The optically guided positioning system relies on detection of infrared light-emitting diodes (IRLEDs) attached to a standard target positioner. The IRLEDs are monitored by a commercially available camera system that is interfaced to a personal computer. An IRLED reference is established at the center of stereotactic space, and the computer reports the current position of the IRLEDs relative to this reference position. Using this readout from the computer, the correct stereotactic coordinate can be set directly. Results: Bench testing was performed to compare the accuracy of the optically guided system with that of a floor-stand system, that can be considered an absolute reference. This testing showed that coordinate localization using the IRLED system to track translations agreed with the absolute to within 0.1 ± 0.1 mm. As rotations for noncoplanar couch angles were included, the inaccuracy was increased to 0.2 ± 0.1 mm. Conclusions: IRLED technology improves the accuracy of patient localization relative to the linac isocenter in comparison with conventional couch-mounted systems. Further, the patient's position can be monitored in real time as the couch is rotated for all treatment angles. Thus, any errors introduced by couch inaccuracies can be detected and corrected

Gamma knife radiosurgery for cerebellopontine angle epidermoid tumors.

Science.gov (United States)

El-Shehaby, Amr M N; Reda, Wael A; Abdel Karim, Khaled M; Emad Eldin, Reem M; Nabeel, Ahmed M

2017-01-01

Intracranial epidermoid tumors are commonly found in the cerebellopontine angle where they usually present with either trigeminal neuralgia or hemifacial spasm. Radiosurgery for these tumors has rarely been reported. The purpose of this study is to assess the safety and clinical outcome of the treatment of cerebellopontine epidermoid tumors with gamma knife radiosurgery. This is a retrospective study involving 12 patients harboring cerebellopontine angle epidermoid tumors who underwent 15 sessions of gamma knife radiosurgery. Trigeminal pain was present in 8 patients and hemifacial spasm in 3 patients. All cases with trigeminal pain were receiving medication and still uncontrolled. One patient with hemifacial spasm was medically controlled before gamma knife and the other two were not. Two patients had undergone surgical resection prior to gamma knife treatment. The median prescription dose was 11 Gy (10-11 Gy). The tumor volumes ranged from 3.7 to 23.9 cc (median 10.5 cc). The median radiological follow up was 2 years (1-5 years). All tumors were controlled and one tumor shrank. The median clinical follow-up was 5 years. The trigeminal pain improved or disappeared in 5 patients, and of these, 4 cases stopped their medication and one decreased it. The hemifacial spasm resolved in 2 patients who were able to stop their medication. Facial palsy developed in 1 patient and improved with conservative treatment. Transient diplopia was also reported in 2 cases. Gamma knife radiosurgery provides good clinical control for cerebellopontine angle epidermoid tumors.

Outcome After Pituitary Radiosurgery for Thalamic Pain Syndrome

International Nuclear Information System (INIS)

Hayashi, Motohiro; Chernov, Mikhail F.; Taira, Takaomi; Ochiai, Taku; Nakaya, Kotaro; Tamura, Noriko; Goto, Shinichi; Yomo, Shoji; Kouyama, Nobuo; Katayama, Yoko; Kawakami, Yoriko; Izawa, Masahiro; Muragaki, Yoshihiro

2007-01-01

Purpose: To evaluate outcomes after pituitary radiosurgery in patients with post-stroke thalamic pain syndrome. Methods and Materials: From 2002 to 2006, 24 patients with thalamic pain syndrome underwent pituitary radiosurgery at Tokyo Women's Medical University and were followed at least 12 months thereafter. The radiosurgical target was defined as the pituitary gland and its connection with the pituitary stalk. The maximum dose varied from 140 to 180 Gy. Mean follow-up after treatment was 35 months (range, 12-48 months). Results: Initial pain reduction, usually within 48 h after radiosurgery, was marked in 17 patients (71%). However, in the majority of cases the pain recurred within 6 months after treatment, and at the time of the last follow-up examination durable pain control was marked in only 5 patients (21%). Ten patients (42%) had treatment-associated side effects. Anterior pituitary abnormalities were marked in 8 cases and required hormonal replacement therapy in 3; transient diabetes insipidus was observed in 2 cases, transient hyponatremia in 1, and clinical deterioration due to increase of the numbness severity despite significant reduction of pain was seen once. Conclusions: Pituitary radiosurgery for thalamic pain results in a high rate of initial efficacy and is accompanied by acceptable morbidity. It can be used as a primary minimally invasive management option for patients with post-stroke thalamic pain resistant to medical therapy. However, in the majority of cases pain recurrence occurs within 1 year after treatment

Leksell Gamma Knife radiosurgery of the jugulotympanic glomus tumor: long-term results.

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Liscak, Roman; Urgosik, Dusan; Chytka, Tomas; Simonova, Gabriela; Novotny, Josef; Vymazal, Josef; Guseynova, Khumar; Vladyka, Vilibald

2014-12-01

Glomus tumors usually display indolent behavior, and the effectiveness of radiation in stopping their growth can be assessed after long-term follow-up. Currently only midterm results of radiosurgery are available, so the authors included patients treated by Gamma Knife at least 10 years ago in this study to obtain a perspective of long-term results. During the period from 1992 to 2003, the Gamma Knife was used to treat 46 patients with glomus tumors. The age of the patients ranged from 21 to 79 years (median 56 years). Gamma Knife radiosurgery was the primary treatment in 17 patients (37%). Open surgery preceded radiosurgery in 46% of cases, embolization in 17%, and fractionated radiotherapy in 4%. The volume of the tumor ranged from 0.2 to 24.3 cm(3) (median 3.6 cm(3)). The minimal dose to the tumor margin ranged between 10 and 30 Gy (median 20 Gy). One patient was lost for follow-up after radiosurgery. Clinical follow-up was available in 45 patients and 44 patients were followed with MRI in a follow-up period that ranged from 12 to 217 months (median 118 months). Neurological deficits improved in 19 (42%) of 45 patients and deteriorated in 2 patients (4%). Tumor size decreased in 34 (77%) of 44 patients with imaging follow-up, while an increase in volume was observed in 1 patient (2%) 182 months after radiosurgery and Gamma Knife treatment was repeated. One patient underwent another Gamma Knife treatment for secondary induced meningioma close to the glomus tumor 98 months after initial radiosurgical treatment. Seven patients died 22-96 months after radiosurgery (median 48 months), all for unrelated reasons. Radiosurgery has proved to be a safe treatment with a low morbidity rate and a reliable long-term antiproliferative effect.

Gamma knife radiosurgery of radiation-induced intracranial tumors: Local control, outcomes, and complications

International Nuclear Information System (INIS)

Jensen, Ashley W.; Brown, Paul D.; Pollock, Bruce E.; Stafford, Scott L.; Link, Michael J.; Garces, Yolanda I.; Foote, Robert L.; Gorman, Deborah A.; Schomberg, Paula J.

2005-01-01

Purpose: To determine local control (LC) and complication rates for patients who underwent radiosurgery for radiation-induced intracranial tumors. Methods and Materials: Review of a prospectively maintained database (2,714 patients) identified 16 patients (20 tumors) with radiation-induced tumors treated with radiosurgery between 1990 and 2004. Tumor types included typical meningioma (n = 17), atypical meningioma (n = 2), and schwannoma (n 1). Median patient age at radiosurgery was 47.5 years (range, 27-70 years). The median tumor margin dose was 16 Gy (range, 12-20 Gy). Median follow-up was 40.2 months (range, 10.8-146.2 months). Time-to-event outcomes were calculated with Kaplan-Meier estimates. Results: Three-year and 5-year LC rates were 100%. Three-year and 5-year overall survival rates were 92% and 80%, respectively. Cause-specific survival rates at 3 and 5 years were 100%. Three patients died: 1 had in-field progression 65.1 months after radiosurgery and later died of the tumor, 1 died of progression of a preexisting brain malignancy, and 1 died of an unrelated cause. One patient had increased seizure activity that correlated with development of edema seen on neuroimaging. Conclusions: LC, survival, and complication rates in our series are comparable to those in previous reports of radiosurgery for intracranial meningiomas. Also, LC rates with radiosurgery are at least comparable to those of surgical series for radiation-induced meningiomas. Radiosurgery is a safe and effective treatment option for radiation-induced intracranial tumors, most of which are typical meningiomas

Peritumoral hemorrhage after radiosurgery for metastatic brain tumor; A case report

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Motozaki, Takahiko (Nishinomiya City General Hospital, Hyogo (Japan)); Ban, Sadahiko; Yamamoto, Toyoshiro; Hamasaki, Masatake

1994-08-01

An unusual case of peritumoral hemorrhage after radiosurgery for the treatment of metastatic brain tumor is reported. This 64-year-old woman had a history of breast cancer and underwent right mastectomy in 1989. She remained well until January 1993, when she started to have headache, nausea and speech disturbance, and was hospitalized on February 25, 1993. Neurological examination disclosed right hemiparesis and bilateral papilledema. CT scan and MR imaging showed a solitary round mass lesion in the left basal ganglia region. It was a well-demarcated, highly enhanced mass, 37 mm in diameter. Cerebral angiography confirmed a highly vascular mass lesion in the same location. She was treated with radiosurgery on March 8 (maximum dose was 20 Gy in the center and 10 Gy in the peripheral part of the tumor). After radiosurgery, she had an uneventful course and clinical and radiosurgical improvement could be detected. Her neurological symptoms and signs gradually improved and reduction of the tumor size and perifocal edema could be seen one month after radiosurgery. However, 6 weeks after radiosurgery, she suddenly developed semicoma and right hemiplegia. CT scan disclosed a massive peritumoral hemorrhage. Then, emergency craniotomy, evacuation of the hematoma and total removal of the tumor were performed on April 24. Histopathological diagnosis was adenocarcinoma. It was the same finding as that of the previous breast cancer. Histopathological examination revealed necrosis without tumor cells in the center and residual tumor cells in the peripheral part of the tumor. It is postulated that peritumoral hemorrhage was caused by hemodynamic changes in the vascular-rich tumor after radiosurgery and breakdown of the fragile abnormal vessels in the peripheral part of the tumor. (author).

Radiosurgery and the double logistic product formula

International Nuclear Information System (INIS)

Flickinger, J.C.; Steiner, L.

1990-01-01

The double logistic product formula is proposed as a method for predicting the probability of developing brain necrosis after high dose irradiation of small target volumes as used in stereotactic radiosurgery. Dose-response data observed for the production of localized radiation necreosis for treating intractable pain with the original Leksell gamma unit were used to choose the best fitting parameters for the double logistic product formula. This model can be used with either exponential or linear quadratic formulas to account for the effects of dose, fractionation and time in addition to volume. Dose-response predictions for stereotactic radiosurgery with different sized collimators are presented. (author). 41 refs.; 5 figs.; 1 tab

Improved results for vestibular schwannoma radiosurgery

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Flickinger, J C; Kondziolka, D; Pollock, B; Lunsford, L D

1995-07-01

PURPOSE/OBJECTIVE: Treatment techniques in radiosurgery have changed since 1987. We reviewed patients who received radiosurgery for vestibular schwannoma to identify these changes and to investigate any differences in tumor control and complications. MATERIALS and METHODS: One hundred thirty-eight unilateral vestibular schwannoma patients with a minimum follow-up of two years after treatment with gamma knife radiosurgery between 1987 and 1992 were analyzed. The early treatment group consisted of 55 patients treated between 1987-1989 (median: tumor volume 3.63 cc, Dmin 18.1 Gy, Dmax 35.4 Gy, isocenters 2.3, follow-up 50.4 mos.). The later treatment group consisted of 83 patients treated between 1990-1992 (median: tumor volume 3.81 cc, Dmin 16.0 Gy, Dmax 31.6 Gy, isocenters 4.7, follow-up 35.8 mos.) RESULTS: Clinical tumor recurrence requiring surgical intervention occurred in one patient in each group. The overall actuarial clinical tumor control rate was 98%. Slight increases in tumor size (1 to 2 mm) were identified in five other patients not requiring intervention, because of no further tumor growth (n=4) or shrinkage (n=1). This led to an overall radiologic tumor control rate of 92% (not significantly different in either group). Compared to the early treatment group, the incidence of facial neuropathy (temporary or permanent) decreased in the later group (49% vs. 11%, p < 0.0001), as did trigeminal neuropathy (40% vs. 8%, p < 0.0001). Serviceable hearing preservation improved only slightly in the later group (27% vs. 40%, p = 0.70). CONCLUSION: We document a significant decrease in the morbidity of vestibular schwannoma radiosurgery over this time period with no decrease in the high rate of tumor control. This improvement is attributed to a) better conformal dose-planning with stereotactic MRI rather than CT, b) an increase in the number of isocenters used, and c) a reduction in the average dose administered by 2 Gy.

Linear accelerator radiosurgery for arteriovenous malformations: Updated literature review.

Science.gov (United States)

Yahya, S; Heyes, G; Nightingale, P; Lamin, S; Chavda, S; Geh, I; Spooner, D; Cruickshank, G; Sanghera, P

2017-04-01

Arteriovenous malformations (AVMs) are the leading causing of intra-cerebral haemorrhage. Stereotactic radiosurgery (SRS) is an established treatment for arteriovenous malformations (AVM) and commonly delivered using Gamma Knife within dedicated radiosurgery units. Linear accelerator (LINAC) SRS is increasingly available however debate remains over whether it offers an equivalent outcome. The aim of this project is to evaluate the outcomes using LINAC SRS for AVMs used within a UK neurosciences unit and review the literature to aid decision making across various SRS platforms. Results have shown comparability across platforms and strongly supports that an adapted LINAC based SRS facility within a dynamic regional neuro-oncology department delivers similar outcomes (in terms of obliteration and toxicity) to any other dedicated radio-surgical platform. Locally available facilities can facilitate discussion between options however throughput will inevitably be lower than centrally based dedicated national radiosurgery units. Copyright © 2016. Published by Elsevier Ltd.

Stereotactic radiosurgery for brain metastasis: Pitie-Salpetriere Hospital experience

International Nuclear Information System (INIS)

Feuvret, L.; Germain, I.; Cornu, P.; Boisserie, G.; Dormont, D.; Hardiman, C.; Tep, B.; Faillot, T.; Duffau, H.; Simon, J.M.; Dendale, R.; Delattre, J.Y.; Poisson, M.; Marsault, C.; Philippon, J.; Fohanno, D.; Baillet, F.; Mazeron, J.J.

1998-01-01

Retrospective analysis of the influence of clinical and technical factors on local control and survival after radiosurgery for brain metastasis. From january 1994 to December 1996, 42 patients presenting with 71 metastases underwent radiosurgery for brain metastasis. The median age was 56 years and the median Karnofsky index 80. Primary sites included: lung (20 patients), kidney (seven), breast (five), colon (two), melanoma (three), osteosarcoma (one) and it was unknown for three patients. Seventeen patients had extracranial metastasis. Twenty-four patients were treated at recurrence which occurred after whole brain irradiation (12 patients), surgical excision (four) or after both treatments (eight). Thirty-six sessions of radiosurgery have been realized for one metastasis and 13 for two, three or four lesions. The median metastasis diameter was 21 mm and the median volume 1.7 cm 3 . The median peripheral dose to the lesion was 14 Gy, and the median dose at the isocenter 20 Gy. Sixty-five metastasis were evaluable for response analysis. The overall local control rate was 82% and the 1-year actuarial rate was 72%. In univariate analysis, theoretical radioresistance (P = 0.001), diameter less than 3 cm (P = 0.039) and initial treatment with radiosurgery (P 0.041) were significantly associated with increased local control. Only the first two factors remained significant in multivariate analysis. No prognostic factor of overall survival was identified. The median survival was 12 months. Six patients had a symptomatic oedema (RTOG grade 2), only one of which requiring a surgical excision. In conclusion, 14 Gy delivered at the periphery of metastasis seems to be a sufficient dose to control most brain metastases, with a minimal toxicity. Better results were obtained for lesions initially treated with radiosurgery, theoretically radioresistant and with a diameter less than 3 cm. (authors)

The current role of Gamma Knife radiosurgery in the management of intracranial haemangiopericytoma.

Science.gov (United States)

Spina, Alfio; Boari, Nicola; Gagliardi, Filippo; Donofrio, Carmine A; Franzin, Alberto; Mortini, Pietro

2016-04-01

Haemangiopericytomas (HPCs) are rare tumours characterised by aggressive behaviour with tendency to local recurrence and to metastasise. WHO grade II and grade III tumours show different progression-free survival and overall survival rates. Gross total tumour resection is still considered the treatment of choice. Adjuvant radiation therapies represent an option in the treatment strategy regardless the extent of resection. Based on this consideration, Gamma Knife radiosurgery has been introduced either as a primary treatment or as an adjuvant treatment for residual or recurrent tumours. A systematic search was performed on PubMed, Web of Science and Google Scholar for clinical series reporting Gamma Knife radiosurgery, Cyberknife and Linear Accelerator (LINAC) for the management of intracranial HPCs. Fourteen studies focusing on the effects of Gamma Knife radiosurgery for intracranial HPCs were included. Four studies reported data on Cyberknife radiosurgery and LINAC. A total of 208 patients harbouring 366 tumours have been reported. Patient's features, radiosurgical treatment characteristics and follow-up data of the pertinent literature have been critically revised. Gamma Knife radiosurgery and the other radiosurgical techniques represent a feasible and effective therapy in the management of HPCs. Tumour control and survival rate are comparable to those reported for radiotherapy. Further studies should be focused to define the exact role of Gamma Knife radiosurgery in the management of HPCs.

Radiosurgery for brain metastases: a score index for predicting prognosis

International Nuclear Information System (INIS)

Weltman, Eduardo; Salvajoli, Joao Victor; Brandt, Reynaldo Andre; Morais Hanriot, Rodrigo de; Prisco, Flavio Eduardo; Cruz, Jose Carlos; Oliveira Borges, Sandra Regina de; Wajsbrot, Dalia Ballas

2000-01-01

Purpose: To analyze a prognostic score index for patients with brain metastases submitted to stereotactic radiosurgery (the Score Index for Radiosurgery in Brain Metastases [SIR]). Methods and Materials: Actuarial survival of 65 brain metastases patients treated with radiosurgery between July 1993 and December 1997 was retrospectively analyzed. Prognostic factors included age, Karnofsky performance status (KPS), extracranial disease status, number of brain lesions, largest brain lesion volume, lesions site, and receiving or not whole brain irradiation. The SIR was obtained through summation of the previously noted first five prognostic factors. Kaplan-Meier actuarial survival curves for all prognostic factors, SIR, and recursive partitioning analysis (RPA) (RTOG prognostic score) were calculated. Survival curves of subsets were compared by log-rank test. Application of the Cox model was utilized to identify any correlation between prognostic factors, prognostic scores, and survival. Results: Median overall survival from radiosurgery was 6.8 months. Utilizing univariate analysis, extracranial disease status, KPS, number of brain lesions, largest brain lesion volume, RPA, and SIR were significantly correlated with prognosis. Median survival for the RPA classes 1, 2, and 3 was 20.19 months, 7.75 months, and 3.38 months respectively (p = 0.0131). Median survival for patients, grouped under SIR from 1 to 3, 4 to 7, and 8 to 10, was 2.91 months, 7.00 months, and 31.38 months respectively (p = 0.0001). Using the Cox model, extracranial disease status and KPS demonstrated significant correlation with prognosis (p 0.0001 and 0.0004 respectively). Multivariate analysis also demonstrated significance for SIR and RPA when tested individually (p = 0.0001 and 0.0040 respectively). Applying the Cox Model to both SIR and RPA, only SIR reached independent significance (p = 0.0004). Conclusions: Systemic disease status, KPS, SIR, and RPA are reliable prognostic factors for patients

Radiosurgery of Glomus Jugulare Tumors: A Meta-Analysis

International Nuclear Information System (INIS)

Guss, Zachary D.; Batra, Sachin; Limb, Charles J.; Li, Gordon; Sughrue, Michael E.; Redmond, Kristin; Rigamonti, Daniele; Parsa, Andrew T.; Chang, Steven; Kleinberg, Lawrence; Lim, Michael

2011-01-01

Purpose: During the past two decades, radiosurgery has arisen as a promising approach to the management of glomus jugulare. In the present study, we report on a systematic review and meta-analysis of the available published data on the radiosurgical management of glomus jugulare tumors. Methods and Materials: To identify eligible studies, systematic searches of all glomus jugulare tumors treated with radiosurgery were conducted in major scientific publication databases. The data search yielded 19 studies, which were included in the meta-analysis. The data from 335 glomus jugulare patients were extracted. The fixed effects pooled proportions were calculated from the data when Cochrane's statistic was statistically insignificant and the inconsistency among studies was 36 months. In these studies, 95% of patients achieved clinical control and 96% achieved tumor control. The gamma knife, linear accelerator, and CyberKnife technologies all exhibited high rates of tumor and clinical control. Conclusions: The present study reports the results of a meta-analysis for the radiosurgical management of glomus jugulare. Because of its high effectiveness, we suggest considering radiosurgery for the primary management of glomus jugulare tumors.

Treatment of acoustic neuroma: stereotactic radiosurgery vs. microsurgery

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Karpinos, Marianna; Teh, Bin S.; Zeck, Otto; Carpenter, L. Steven; Phan, Chris; Mai, W.-Y.; Lu, Hsin H.; Chiu, J. Kam; Butler, E. Brian; Gormley, William B.; Woo, Shiao Y.

2002-01-01

Purpose: Two major treatment options are available for patients with acoustic neuroma, microsurgery and radiosurgery. Our objective was to compare these two treatment modalities with respect to tumor growth control, hearing preservation, development of cranial neuropathies, complications, functional outcome, and patient satisfaction. Methods and Materials: To compare radiosurgery with microsurgery, we analyzed 96 patients with unilateral acoustic neuromas treated with Leksell Gamma Knife or microsurgery at Memorial Hermann Hospital, Houston, Texas, between 1993 and 2000. Radiosurgery technique involved multiple isocenter (1-30 single fraction fixed-frame magnetic resonance imaging) image-based treatment with a mean dose prescription of 14.5 Gy. Microsurgery included translabyrinthine, suboccipital, and middle fossa approaches with intraoperative neurophysiologic monitoring. Preoperative patient characteristics were similar except for tumor size and age. Patients undergoing microsurgery were younger with larger tumors compared to the radiosurgical group. The tumors were divided into small 4.0 cm. Median follow-up of the radiosurgical group was longer than the microsurgical group, 48 months (3-84 months) vs. 24 months (3-72 months). Results: There was no statistical significance in tumor growth control between the two groups, 100% in the microsurgery group vs. 91% in the radiosurgery group (p>0.05). Radiosurgery was more effective than microsurgery in measurable hearing preservation, 57.5% vs. 14.4% (p=0.01). There was no difference in serviceable hearing preservation between the two groups. Microsurgery was associated with a greater rate of facial and trigeminal neuropathy in the immediate postoperative period and at long-term follow-up. The rate of development of facial neuropathy was significantly higher in the microsurgical group than in the radiosurgical group (35% vs. 0%, p<0.01 in the immediate postsurgical period and 35.3% vs. 6.1%, p=0.008, at long

Treatment of acoustic neuroma: stereotactic radiosurgery vs. microsurgery

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Karpinos, Marianna; Teh, Bin S; Zeck, Otto; Carpenter, L Steven; Phan, Chris; Mai, W -Y; Lu, Hsin H; Chiu, J Kam; Butler, E Brian; Gormley, William B; Woo, Shiao Y

2002-12-01

Purpose: Two major treatment options are available for patients with acoustic neuroma, microsurgery and radiosurgery. Our objective was to compare these two treatment modalities with respect to tumor growth control, hearing preservation, development of cranial neuropathies, complications, functional outcome, and patient satisfaction. Methods and Materials: To compare radiosurgery with microsurgery, we analyzed 96 patients with unilateral acoustic neuromas treated with Leksell Gamma Knife or microsurgery at Memorial Hermann Hospital, Houston, Texas, between 1993 and 2000. Radiosurgery technique involved multiple isocenter (1-30 single fraction fixed-frame magnetic resonance imaging) image-based treatment with a mean dose prescription of 14.5 Gy. Microsurgery included translabyrinthine, suboccipital, and middle fossa approaches with intraoperative neurophysiologic monitoring. Preoperative patient characteristics were similar except for tumor size and age. Patients undergoing microsurgery were younger with larger tumors compared to the radiosurgical group. The tumors were divided into small <2.0 cm, medium 2.0-3.9 cm, or large >4.0 cm. Median follow-up of the radiosurgical group was longer than the microsurgical group, 48 months (3-84 months) vs. 24 months (3-72 months). Results: There was no statistical significance in tumor growth control between the two groups, 100% in the microsurgery group vs. 91% in the radiosurgery group (p>0.05). Radiosurgery was more effective than microsurgery in measurable hearing preservation, 57.5% vs. 14.4% (p=0.01). There was no difference in serviceable hearing preservation between the two groups. Microsurgery was associated with a greater rate of facial and trigeminal neuropathy in the immediate postoperative period and at long-term follow-up. The rate of development of facial neuropathy was significantly higher in the microsurgical group than in the radiosurgical group (35% vs. 0%, p<0.01 in the immediate postsurgical period and 35

Results of stereotactic radiosurgery for patients with imaging defined cavernous sinus meningiomas

International Nuclear Information System (INIS)

Pollock, Bruce E.; Stafford, Scott L.

2005-01-01

Introduction: The purpose of this study was to evaluate the efficacy and safety of stereotactic radiosurgery as primary management for patients with imaging defined cavernous sinus meningiomas. Methods: Between 1992 and 2001, 49 patients had radiosurgery for dural-based masses of the cavernous sinus presumed to be meningiomas. The mean patient age was 55.5 years. The mean tumor volume was 10.2 mL; the mean tumor margin dose was 15.9 Gy. The mean follow-up was 58 months (range, 16-144 months). Results: No tumor enlarged after radiosurgery. Twelve of 38 patients (26%) with preexisting diplopia or facial numbness/pain had improvement in cranial nerve function. Five patients (10%) had new (n = 3) or worsened (n = 2) trigeminal dysfunction; 2 of these patients (4%) underwent surgery at 20 and 25 months after radiosurgery despite no evidence of tumor progression. Neither patient improved after partial tumor resection. One patient (2%) developed an oculomotor nerve injury. One patient (2%) had an ischemic stroke related to occlusion of the cavernous segment of the internal carotid artery. Event-free survival was 98%, 85%, and 80% at 1, 3, and 7 years after radiosurgery, respectively. Univariate analysis of patient and dosimetric factors found no analyzed factor correlated with postradiosurgical morbidity. Conclusions: Radiosurgery was an effective primary management strategy for patients with an imaging defined cavernous sinus meningioma. Except in situations of symptomatic mass effect, unusual clinical presentation, or atypical imaging features, surgery to confirm the histologic diagnosis is unlikely to provide clinical benefit

SU-E-J-34: Clinical Evaluation of Targeting Accuracy and Tractogrphy Delineation of Radiosurgery

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Juh, R; Suh, T; Kim, Y; Han, J; Kim, C; Oh, C; Kim, D [Seoul National University Bundang Hospital (Korea, Republic of)

2014-06-01

Purpose: Focal radiosurgery is a common treatment modality for trigeminal neuralgia (TN), a neuropathic facial pain condition. Assessment of treatment effectiveness is primarily clinical, given the paucity of investigational tools to assess trigeminal nerve changes. The efficiency of radiosurgery is related to its highly precise targeting. We assessed clinically the targeting accuracy of radiosurgery with Gamma knife. We hypothesized that trigeminal tractography provides more information than 2D-MR imaging, allowing detection of unique, focal changes in the target area after radiosurgery. Methods: Sixteen TN patients (2 females, 4 male, average age 65.3 years) treated with Gamma Knife radiosurgery, 40 Gy/50% isodose line underwent 1.5Tesla MR trigeminal nerve . Target accuracy was assessed from deviation of the coordinates of the target compared with the center of enhancement on post MRI. Radiation dose delivered at the borders of contrast enhancement was evaluated Results: The median deviation of the coordinates between the intended target and the center of contrast enhancement was within 1mm. The radiation doses fitting within the borders of the contrast enhancement the target ranged from 37.5 to 40 Gy. Trigeminal tractography accurately detected the radiosurgical target. Radiosurgery resulted in 47% drop in FA values at the target with no significant change in FA outside the target, suggesting that radiosurgery primarily affects myelin. Tractography was more sensitive, since FA changes were detected regardless of trigeminal nerve enhancement Conclusion: The median deviation found in clinical assessment of gamma knife treatment for TN Is low and compatible with its high rate of efficiency. DTI parameters accurately detect the effects of focal radiosurgery on the trigeminal nerve, serving as an in vivo imaging tool to study TN. This study is a proof of principle for further assessment of DTI parameters to understand the pathophysiology of TN and treatment effects.

Objective specific beam generation for image guided robotic radiosurgery

International Nuclear Information System (INIS)

Schlaefer, A.; Jungmann, O.; Schweikard, A.; Kilby, W.

2007-01-01

Robotic radiosurgery enables precise dose delivery throughout the body. Planning for robotic radiosurgery comprises of finding a suitable set of beams and beam weights. The problem can be addressed by generating a large set of candidate beams, and selection of beams with nonzero weight by mathematical programming. We propose to use different randomized beam generation methods depending on the type of lesion and the clinical objective. Results for three patient cases indicate that this can improve the plan quality. (orig.)

Objective specific beam generation for image guided robotic radiosurgery

Energy Technology Data Exchange (ETDEWEB)

Schlaefer, A.; Jungmann, O.; Schweikard, A. [Inst. for Robotics and Cognitive Systems, Univ. of Luebeck (Germany); Kilby, W. [Accuray Inc., Sunnyvale, CA (United States)

2007-06-15

Robotic radiosurgery enables precise dose delivery throughout the body. Planning for robotic radiosurgery comprises of finding a suitable set of beams and beam weights. The problem can be addressed by generating a large set of candidate beams, and selection of beams with nonzero weight by mathematical programming. We propose to use different randomized beam generation methods depending on the type of lesion and the clinical objective. Results for three patient cases indicate that this can improve the plan quality. (orig.)

Stereotactic Radiosurgery and Hypofractionated Radiotherapy for Glioblastoma.

Science.gov (United States)

Shah, Jennifer L; Li, Gordon; Shaffer, Jenny L; Azoulay, Melissa I; Gibbs, Iris C; Nagpal, Seema; Soltys, Scott G

2018-01-01

Glioblastoma is the most common primary brain tumor in adults. Standard therapy depends on patient age and performance status but principally involves surgical resection followed by a 6-wk course of radiation therapy given concurrently with temozolomide chemotherapy. Despite such treatment, prognosis remains poor, with a median survival of 16 mo. Challenges in achieving local control, maintaining quality of life, and limiting toxicity plague treatment strategies for this disease. Radiotherapy dose intensification through hypofractionation and stereotactic radiosurgery is a promising strategy that has been explored to meet these challenges. We review the use of hypofractionated radiotherapy and stereotactic radiosurgery for patients with newly diagnosed and recurrent glioblastoma. Copyright © 2017 by the Congress of Neurological Surgeons.

Stereotactic radiosurgery. The role of charged particles

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Levy, R.P.; Schulte, R.W.M.; Slater, J.D.; Miller, D.W.; Slater, J.M. [Loma Linda Univ. Medical Center, CA (United States). Dept. of Radiation Medicine

1999-08-01

Stereotactic radiosurgery using charged-particle beams has been the subject of biomedical research and clinical development for more than 50 years. Charged particles of proton mass or greater manifest unique physical properties that can be used to place a high dose of radiation preferentially within the boundaries of a deeply located intracranial target volume. Since 1954, nearly 10 000 patients have been treated using this technique. Treated disorders include pituitary tumors, vascular malformations, primary and metastatic brain tumors, and subfoveal neovascularization. Charged-particle radiosurgery is particularly advantageous for the conformal treatment of large and/or irregularly shaped lesions, or for the treatment of lesions located in front of or adjacent to sensitive brain structures. (orig.)

Stereotactic radiosurgery. The role of charged particles

International Nuclear Information System (INIS)

Levy, R.P.; Schulte, R.W.M.; Slater, J.D.; Miller, D.W.; Slater, J.M.

1999-01-01

Stereotactic radiosurgery using charged-particle beams has been the subject of biomedical research and clinical development for more than 50 years. Charged particles of proton mass or greater manifest unique physical properties that can be used to place a high dose of radiation preferentially within the boundaries of a deeply located intracranial target volume. Since 1954, nearly 10 000 patients have been treated using this technique. Treated disorders include pituitary tumors, vascular malformations, primary and metastatic brain tumors, and subfoveal neovascularization. Charged-particle radiosurgery is particularly advantageous for the conformal treatment of large and/or irregularly shaped lesions, or for the treatment of lesions located in front of or adjacent to sensitive brain structures. (orig.)

Fractionated radiosurgery for painful spinal metastases: DOSIS - a phase II trial

International Nuclear Information System (INIS)

Guckenberger, Matthias; Hawkins, Maria; Flentje, Michael; Sweeney, Reinhart A

2012-01-01

One third of all cancer patients will develop bone metastases and the vertebral column is involved in approximately 70% of these patients. Conventional radiotherapy with of 1–10 fractions and total doses of 8-30 Gy is the current standard for painful vertebral metastases; however, the median pain response is short with 3–6 months and local tumor control is limited with these rather low irradiation doses. Recent advances in radiotherapy technology – intensity modulated radiotherapy for generation of highly conformal dose distributions and image-guidance for precise treatment delivery – have made dose-escalated radiosurgery of spinal metastases possible and early results of pain and local tumor control are promising. The current study will investigate efficacy and safety of radiosurgery for painful vertebral metastases and three characteristics will distinguish this study. 1) A prognostic score for overall survival will be used for selection of patients with longer life expectancy to allow for analysis of long-term efficacy and safety. 2) Fractionated radiosurgery will be performed with the number of treatment fractions adjusted to either good (10 fractions) or intermediate (5 fractions) life expectancy. Fractionation will allow inclusion of tumors immediately abutting the spinal cord due to higher biological effective doses at the tumor - spinal cord interface compared to single fraction treatment. 3) Dose intensification will be performed in the involved parts of the vertebrae only, while uninvolved parts are treated with conventional doses using the simultaneous integrated boost concept. It is the study hypothesis that hypo-fractionated image-guided radiosurgery significantly improves pain relief compared to historic data of conventionally fractionated radiotherapy. Primary endpoint is pain response 3 months after radiosurgery, which is defined as pain reduction of ≥ 2 points at the treated vertebral site on the 0 to 10 Visual Analogue Scale. 60 patients

Linac based radiosurgery and stereotactic radiotherapy

International Nuclear Information System (INIS)

Mackie, T.R.

2008-01-01

The following topics were discussed: Definition of stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT); Stereo market; Indications for SRS/SRT; History of linac-based SRS/SRT; Variety of systems; QA for SRS; Localization; and Imaging. (P.A.)

Role of gamma knife radiosurgery in neurosurgery. Past and future perspectives

International Nuclear Information System (INIS)

Koga, Tomoyuki; Shin, Masahiro; Saito, Nobuhito

2010-01-01

The gamma knife was the first radiosurgical device developed at the Karolinska Institute in 1967. Stereotactic radiosurgery using the gamma knife has been widely accepted in clinical practice and has contributed to the development of neurosurgery. More than 500,000 patients have been treated by gamma knife stereotactic radiosurgery so far, and the method is now an indispensable neurosurgical tool. Here we review long-term outcomes and development of stereotactic radiosurgery using the gamma knife and discuss its future perspectives. The primary role of stereotactic radiosurgery is to control small well-demarcated lesions such as metastatic brain tumors, meningiomas, schwannomas, and pituitary adenomas while preserving the function of surrounding brain tissue. The gamma knife has been used as a primary treatment or in combination with surgery, and some applications have been accepted as standard treatment in the field of neurosurgery. Treatment of cerebral arteriovenous malformations has also been drastically changed after emergence of this technology. Controlling functional disorders is another role of stereotactic radiosurgery. There is a risk of radiation-induced adverse events, which are usually mild and less frequent. However, especially in large or invasive lesions, those risks are not negligible and pose limitations. Advancement of irradiation technology and dose planning software have enabled more sophisticated and safer treatment, and further progress will contribute to better treatment outcomes not only for brain lesions but also for cervical lesions with less invasive treatment. (author)

Analysis of neurological sequelae from radiosurgery of arteriovenous malformations: how location effects outcome

International Nuclear Information System (INIS)

Flickinger, John C.; Kondziolka, Douglas; Maitz, Ann H.; Lunsford, L. Dade

1997-01-01

Purpose/Objective: To elucidate how the risks of developing temporary and permanent neurological sequelae from radiosurgery for arteriovenous malformations (AVM) relate to AVM location, the addition of stereotactic magnetic resonance (MR) imaging to angiographic targeting, and prior hemorrhage or neurological deficits. Materials and Methods: We evaluated follow-up imaging and clinical data in 332 AVM patients who received gamma knife radiosurgery at the University of Pittsburgh between 1987 and 1994. All patients had regular clinical or imaging follow up for a minimum of two years (range: 24-96 mo., median=45 mo.). 83 patients had MR. planning, and 187 previously bled. Results: Symptomatic post-radiosurgery sequelae (any neurological problem including headache) developed in 30/332 patients (9.0%). Symptoms resolved in 58% of patients within 24 mo. with a significantly greater proportion (p=0.006) resolving in patients with Dmin <20 vs. ≥20 Gy (89 vs. 36%). The 7 yr. actuarial rate for developing persistent symptomatic sequelae was 3.8%. We first evaluated the relative risks for different locations to construct a post-radiosurgery injury expression (PIE) score for AVM location (see Table 1). Multivariate logistic regression analysis of symptomatic post-radiosurgery injury identified independent significant correlations with PIE location score (p=0.0007) and 12 Gy volume (p=0.008) but none of the other factors tested (p≥0.3) including the addition of MR targeting, average radiation dose in 20 cc, prior bleed or neurological deficit. We used these results to construct risk prediction models for any symptomatic post-radiosurgery sequelae and for symptomatic necrosis. Conclusion: The risks of complications from AVM radiosurgery can be predicted according to location with the PIE score and by the 12 Gy treatment volume (Table 2)

Dose-Escalation Study for Cardiac Radiosurgery in a Porcine Model

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Blanck, Oliver, E-mail: oliver.blanck@uksh.de [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); CyberKnife Center Northern Germany, Guestrow (Germany); Bode, Frank [Medical Department II, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Gebhard, Maximilian [Institute of Pathology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Hunold, Peter [Department of Radiology and Nuclear Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Brandt, Sebastian [Department of Anaesthesiology and Intensive Care Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Bruder, Ralf [Institute for Robotics and Cognitive Systems, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Grossherr, Martin [Department of Anaesthesiology and Intensive Care Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Vonthein, Reinhard [Institute of Medical Biometry and Statistics, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Rades, Dirk [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); Dunst, Juergen [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck (Germany); University Copenhagen (Denmark)

2014-07-01

Purpose: To perform a proof-of-principle dose-escalation study to radiosurgically induce scarring in cardiac muscle tissue to block veno-atrial electrical connections at the pulmonary vein antrum, similar to catheter ablation. Methods and Materials: Nine mini-pigs underwent pretreatment magnetic resonance imaging (MRI) evaluation of heart function and electrophysiology assessment by catheter measurements in the right superior pulmonary vein (RSPV). Immediately after examination, radiosurgery with randomized single-fraction doses of 0 and 17.5-35 Gy in 2.5-Gy steps were delivered to the RSPV antrum (target volume 5-8 cm{sup 3}). MRI and electrophysiology were repeated 6 months after therapy, followed by histopathologic examination. Results: Transmural scarring of cardiac muscle tissue was noted with doses ≥32.5 Gy. However, complete circumferential scarring of the RSPV was not achieved. Logistic regressions showed that extent and intensity of fibrosis significantly increased with dose. The 50% effective dose for intense fibrosis was 31.3 Gy (odds ratio 2.47/Gy, P<.01). Heart function was not affected, as verified by MRI and electrocardiogram evaluation. Adjacent critical structures were not damaged, as verified by pathology, demonstrating the short-term safety of small-volume cardiac radiosurgery with doses up to 35 Gy. Conclusions: Radiosurgery with doses >32.5 Gy in the healthy pig heart can induce circumscribed scars at the RSPV antrum noninvasively, mimicking the effect of catheter ablation. In our study we established a significant dose-response relationship for cardiac radiosurgery. The long-term effects and toxicity of such high radiation doses need further investigation in the pursuit of cardiac radiosurgery for noninvasive treatment of atrial fibrillation.

Complications from arteriovenous malformation radiosurgery: multivariate analysis and risk modeling

International Nuclear Information System (INIS)

Flickinger, John C.; Kondziolka, Douglas; Pollock, Bruce E.; Maitz, Ann H.; Lunsford, L. Dade

1997-01-01

Purpose/Objective: To assess the relationships of radiosurgery treatment parameters to the development of complications from radiosurgery for arteriovenous malformations (AVM). Methods and Materials: We evaluated follow-up imaging and clinical data in 307 AVM patients who received gamma knife radiosurgery at the University of Pittsburgh between 1987 and 1993. All patients had regular clinical or imaging follow up for a minimum of 2 years (range: 24-96 months, median = 44 months). Results: Post-radiosurgical imaging (PRI) changes developed in 30.5% of patients with regular follow-up magnetic resonance imaging, and were symptomatic in 10.7% of all patients at 7 years. PRI changes resolved within 3 years developed significantly less often (p = 0.0274) in patients with symptoms (52.8%) compared to asymptomatic patients (94.8%). The 7-year actuarial rate for developing persistent symptomatic PRI changes was 5.05%. Multivariate logistic regression modeling found that the 12 Gy volume was the only independent variable that correlated significantly with PRI changes (p < 0.0001) while symptomatic PRI changes were correlated with both 12 Gy volume (p = 0.0013) and AVM location (p 0.0066). Conclusion: Complications from AVM radiosurgery can be predicted with a statistical model relating the risks of developing symptomatic post-radiosurgical imaging changes to 12 Gy treatment volume and location

Stereotactic radiosurgery using a linear accelerator

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Kyuma, Yoshikazu; Hayashi, Akimune; Kitamura, Tatsuo; Yamashita, Koosuke; Muranishi, Hisayuki; Hioki, Minoru [Kanagawa Cancer Center, Yokohama (Japan)

1992-07-01

A basic and clinical study of radiosurgery using the linear accelerator (Linac) system for unremovable deep-seated brain tumors is reported. A Komai stereotactic ring was used to locate the target coordinates. The patient was laid on the Linac treatment table and held in the head fixation system. Irradiation was given in five positions. The dose profile by film dosimetry and Rando phantom was satisfactory. Seventeen tumors in 14 patients were treated. Clinical or histological diagnoses were nine metastases, one benign and two malignant gliomas, one meningioma, and one carcinopharyngioma. Tumor sizes were between 8 and 30 mm. Doses were between 12 and 30 Gy. Computed tomographic evaluation after 3 months of 12 tumors in 11 survivors showed one complete remission, three partial remission, six no change, and two partial deterioration. For progressive tumors, Linac radiosurgery results are excellent. (author).

Therapeutic profile of single-fraction radiosurgery of vestibular schwannoma: unrelated malignancy predicts tumor control

Science.gov (United States)

Wowra, Berndt; Muacevic, Alexander; Fürweger, Christoph; Schichor, Christian; Tonn, Jörg-Christian

2012-01-01

Radiosurgery has become an accepted treatment option for vestibular schwannomas. Nevertheless, predictors of tumor control and treatment toxicity in current radiosurgery of vestibular schwannomas are not well understood. To generate new information on predictors of tumor control and cranial nerve toxicity of single-fraction radiosurgery of vestibular schwannomas, we conducted a single-institution long-term observational study of radiosurgery for sporadic vestibular schwannomas. Minimum follow-up was 3 years. Investigated as potential predictors of tumor control and cranial nerve toxicity were treatment technology; tumor resection preceding radiosurgery; tumor size; gender; patient age; history of cancer, vascular disease, or metabolic disease; tumor volume; radiosurgical prescription dose; and isodose line. Three hundred eighty-six patients met inclusion criteria. Treatment failure was observed in 27 patients. History of unrelated cancer (strongest predictor) and prescription dose significantly predicted tumor control. The cumulative incidence of treatment failure was 30% after 6.5 years in patients with unrelated malignancy and 10% after ≥15 years in patients without such cancer (P making in ambiguous cases. PMID:22561798

A cost-effectiveness and cost-utility analysis of radiosurgery vs. resection for single-brain metastases

International Nuclear Information System (INIS)

Mehta, Minesh; Noyes, William; Craig, Bruce; Lamond, John; Auchter, Richard; French, Molly; Johnson, Mark; Levin, Allan; Badie, Behnam; Robbins, Ian; Kinsella, Timothy

1997-01-01

Purpose: The median survival of well-selected patients with single-brain metastases treated with whole-brain irradiation and resection or radiosurgery is comparable, although a randomized trial of these two modalities has not been performed. In this era of cost containment, it is imperative that health-care professionals make fiscally prudent decisions. The present environment necessitates a critical appraisal of apparently equi-efficacious therapeutic modalities, and it is within this context that we present a comparison of the actual costs of resection and radiosurgery for brain metastases. Methods and Materials: Survival and quality of life outcome data for radiation alone or with surgery were obtained from two randomized trials, and radiosurgical results were obtained from a multiinstitutional analysis that specifically evaluated patients meeting surgical criteria. Only linear accelerator radiosurgery data were considered. Cost analysis was performed from a societal view point, and the following parameters were evaluated: actual cost, cost ratios, cost effectiveness, incremental cost effectiveness, cost utility, incremental cost utility, and national cost burden. The computerized billing records for all patients undergoing resection or radiosurgery for single-brain metastases from January 1989 to July 1994 were reviewed. A total of 46 resections and 135 radiosurgery procedures were performed. During the same time period, 454 patients underwent whole-brain radiation alone. An analysis of the entire bill was performed for each procedure, and each itemized cost was assigned a proportionate figure. The relative cost ratios of resection and radiosurgery were compared using the Wilcoxon rank sum test. Cost effectiveness of each modality, defined as the cost per year of median survival, was evaluated. Incremental cost effectiveness, defined as the additional cost per year of incremental gain in median survival, compared to the next least expensive modality, was also

Development of 3-D Radiosurgery Planning System Using IBM Personal Computer

International Nuclear Information System (INIS)

Suh, Tae Suk; Park, Charn Il; Ha, Sung Whan; Kang, Wee Saing; Suh, Doug Young; Park, Sung Hun

1993-01-01

Recently, stereotactic radiosurgery plan is required with the information of 3-D image and dose distribution. A project has been doing if developing LINAC based stereotactic radiosurgery since April 1991. The purpose of this research is to develop 3-D radiosurgery planning system using personal computer. The procedure of this research is based on two steps. The first step is to develop 3-D localization system, which input the image information of the patient, coordinate transformation, the position and shape of target, and patient contour into computer system using CT image and stereotactic frame. The second step is to develop 3-D dose planning system, which compute dose distribution on image plane, display on high resolution monitor both isodose distribution and patient image simultaneously and develop menu-driven planning system. This prototype of radiosurgery planning system was applied recently for several clinical cases. It was shown that our planning system is fast, accurate and efficient while making it possible to handle various kinds of image modalities such as angiography, CT and MRI. It makes it possible to develop general 3-D planning system using beam eye view or CT simulation in radiation therapy in future

Extracranial Facial Nerve Schwannoma Treated by Hypo-fractionated CyberKnife Radiosurgery.

Science.gov (United States)

Sasaki, Ayaka; Miyazaki, Shinichiro; Hori, Tomokatsu

2016-09-21

Facial nerve schwannoma is a rare intracranial tumor. Treatment for this benign tumor has been controversial. Here, we report a case of extracranial facial nerve schwannoma treated successfully by hypo-fractionated CyberKnife (Accuray, Sunnyvale, CA) radiosurgery and discuss the efficacy of this treatment. A 34-year-old female noticed a swelling in her right mastoid process. The lesion enlarged over a seven-month period, and she experienced facial spasm on the right side. She was diagnosed with a facial schwannoma via a magnetic resonance imaging (MRI) scan of the head and neck and was told to wait until the facial nerve palsy subsides. She was referred to our hospital for radiation therapy. We planned a fractionated CyberKnife radiosurgery for three consecutive days. After CyberKnife radiosurgery, the mass in the right parotid gradually decreased in size, and the facial nerve palsy disappeared. At her eight-month follow-up, her facial spasm had completely disappeared. There has been no recurrence and the facial nerve function has been normal. We successfully demonstrated the efficacy of CyberKnife radiosurgery as an alternative treatment that also preserves neurofunction for facial nerve schwannomas.

Stereotactic radiosurgery for the treatment of brain metastases; results from a single institution experience.

LENUS (Irish Health Repository)

Burke, D

2013-09-01

Stereotactic radiosurgery is frequently used for the treatment of brain metastases. This study provides a retrospective evaluation of patients with secondary lesions of the brain treated with stereotactic radiosurgery (SRS) at our institution.

Gamma Knife Radiosurgery for Patients With Nonfunctioning Pituitary Adenomas: Results From a 15-Year Experience

International Nuclear Information System (INIS)

Pollock, Bruce E.; Cochran, Joseph; Natt, Neena; Brown, Paul D.; Erickson, Dana; Link, Michael J.; Garces, Yolanda I.; Foote, Robert L.; Stafford, Scott L.; Schomberg, Paula J.

2008-01-01

Purpose: To evaluate the efficacy and complications of stereotactic radiosurgery for patients with nonfunctioning pituitary adenomas (NFA). Methods and Materials: This was a retrospective review of 62 patients with NFA undergoing radiosurgery between 1992 and 2004, of whom 59 (95%) underwent prior tumor resection. The median treatment volume was 4.0 cm 3 (range, 0.8-12.9). The median treatment dose to the tumor margin was 16 Gy (range, 11-20). The median maximum point dose to the optic apparatus was 9.5 Gy (range, 5.0-12.6). The median follow-up period after radiosurgery was 64 months (range, 23-161). Results: Tumor size decreased for 37 patients (60%) and remained unchanged for 23 patients (37%). Two patients (3%) had tumor growth outside the prescribed treatment volume and required additional treatment (fractionated radiation therapy, n = 1; repeat radiosurgery, n 1). Tumor growth control was 95% at 3 and 7 years after radiosurgery. Eleven (27%) of 41 patients with normal (n = 30) or partial (n = 11) anterior pituitary function before radiosurgery developed new deficits at a median of 24 months after radiosurgery. The risk of developing new anterior pituitary deficits at 5 years was 32%. The 5-year risk of developing new anterior pituitary deficits was 18% for patients with a tumor volume of ≤4.0 cm 3 compared with 58% for patients with a tumor volume >4.0 cm 3 (risk ratio 4.5; 95% confidence interval = 1.3-14.9, p = 0.02). No patient had a decline in visual function. Conclusions: Stereotactic radiosurgery is effective in the management of patients with residual or recurrent NFA, although longer follow-up is needed to evaluate long-term outcomes. The primary complication is hypopituitarism, and the risk of developing new anterior pituitary deficits correlates with the size of the irradiated tumor

Microsurgical resection of incompletely obliterated intracranial arteriovenous malformations following stereotactic radiosurgery

International Nuclear Information System (INIS)

Chang, S.D.; Steinberg, G.K.; Levy, R.P.; Marks, M.P.; Frankel, K.A.; Shuster, D.L.; Marcellus, M.L.

1998-01-01

Radiosurgery is effective in obliterating small arteriovenous malformations (AVMs), but less successful in thrombosing larger AVMs. This study reviewed patients who underwent surgical resection of their large AVMs following failed radiosurgical obliteration. AVMs from 36 patients (aged 7 to 64 years, mean 29.9) were surgically resected 1 to 11 years after radiosurgery. Initial AVM volumes were 0.7 to 117 cm 3 (mean 21.6 cm 3 ), and radiosurgical doses ranged from 4.6 to 45 Gray equivalent (GyE) (mean 21.1 GyE). Thirty AVMs (83%) were located in eloquent tissue. Venous drainage was deep (14), superficial (13), or both (9). Spetzler grades were II (2), III (12), IV (18), and V (4). Nine patients suffered rehemorrhage after radiosurgery but prior to surgery, while three patients developed radiation necrosis. Twenty-seven patients underwent endovascular embolization prior to surgery. During microsurgical resection, the AVMs were found to be significantly less vascular and more easily resected, compared to AVMs in patients who had not received radiosurgery. Histology showed endothelial proliferation with hyaline and mineralization in vessel walls. Partial or complete thrombosis of some AVM vessels, and evidence of vessel and brain necrosis were noted in many cases. Clinical outcome was excellent or good in 34 cases, with two patients dying of rebleeding from residual AVM. Five patients were neurologically worse following microsurgical resection. Final outcome was largely related to the pretreatment grade. Radiosurgery several years prior to surgical resection appears useful in treating unusually large and complex AVMs. (author)

Fractionated radiosurgery for painful spinal metastases: DOSIS - a phase II trial

Directory of Open Access Journals (Sweden)

Guckenberger Matthias

2012-11-01

Full Text Available Abstract Background One third of all cancer patients will develop bone metastases and the vertebral column is involved in approximately 70% of these patients. Conventional radiotherapy with of 1–10 fractions and total doses of 8-30 Gy is the current standard for painful vertebral metastases; however, the median pain response is short with 3–6 months and local tumor control is limited with these rather low irradiation doses. Recent advances in radiotherapy technology – intensity modulated radiotherapy for generation of highly conformal dose distributions and image-guidance for precise treatment delivery – have made dose-escalated radiosurgery of spinal metastases possible and early results of pain and local tumor control are promising. The current study will investigate efficacy and safety of radiosurgery for painful vertebral metastases and three characteristics will distinguish this study. 1 A prognostic score for overall survival will be used for selection of patients with longer life expectancy to allow for analysis of long-term efficacy and safety. 2 Fractionated radiosurgery will be performed with the number of treatment fractions adjusted to either good (10 fractions or intermediate (5 fractions life expectancy. Fractionation will allow inclusion of tumors immediately abutting the spinal cord due to higher biological effective doses at the tumor - spinal cord interface compared to single fraction treatment. 3 Dose intensification will be performed in the involved parts of the vertebrae only, while uninvolved parts are treated with conventional doses using the simultaneous integrated boost concept. Methods / Design It is the study hypothesis that hypo-fractionated image-guided radiosurgery significantly improves pain relief compared to historic data of conventionally fractionated radiotherapy. Primary endpoint is pain response 3 months after radiosurgery, which is defined as pain reduction of ≥ 2 points at the treated

Role of Adjuvant Radiosurgery after Thoracoscopic Microsurgical Resection of a Spinal Schwannoma

Directory of Open Access Journals (Sweden)

Toba N. Niazi

2012-01-01

Full Text Available Stereotactic radiosurgery to benign tumors of the spine has not been advocated as a primary treatment modality because of the favorable prognosis for these lesions after gross-total resection. There is even less evidence regarding its use as an adjuvant to neurosurgical resection of benign recurrent spinal disease. We describe the case of a 30-year-old man with a thoracic spinal schwannoma who had an interval increase of his lesion five months after thoracoscopic microsurgical resection. The patient opted for noninvasive stereotactic radiosurgery in lieu of additional surgical excision and has had stable disease 15 months after radiosurgical treatment with the linear accelerator (LINAC system. In this setting, stereotactic radiosurgery provided a useful adjunct to thoracoscopic microsurgical resection. Future Class I and II evidence should be sought to evaluate the utility of stereotactic radiosurgery as a primary treatment modality or as an adjuvant for microneurosurgical resection of benign spinal lesions in patients who want noninvasive treatment after disease recurrence or who harbor medical comorbidities that would preclude them from being safe surgical candidates.

Development of a phantom for quality control of radiosurgery

International Nuclear Information System (INIS)

Scheidegger Soboll, D.; Reuters Schelin, H.

2008-01-01

The aim of this work was to build a phantom for quality control of stereotactic radiosurgery on linear accelerators. The outward appearance is a translucent human head filled with water and enclosing an insert with test objects of known shapes. The phantom was submitted to computerized tomography, magnetic resonance imaging and angiography exams, in order to perform a radiosurgery planning. Contours of the internal structures on the therapy planning system were drawn over the MRI images. Through the image fusion of CT and MRI, the contour data was transferred to CT images. Stereotactic registration of CT and angiography was made. One isocenter treatment was created, and using the stereotactic coordinates given by the therapy planning system, the phantom was placed on a linac. X-ray images were performed in order to verify the final positioning of the planned isocenter. In the whole process the phantom showed usefulness and adequacy for the positioning quality control of stereotactic radiosurgery with linacs, according to the main documents concerning the issue. (author)

Pathologic effects of gamma-knife radiosurgery on arteriovenous malformations

International Nuclear Information System (INIS)

Schneider, B.F.; Eberhard, D.A.; Steiner, L.

1995-01-01

Objective: Stereotactic radiosurgery is an effective method for treating many arteriovenous malformations (AVM). Hemodynamic changes and varying degrees of obliteration of an AVM nidus following radiosurgery have been described with angiography, but there have been no detailed reports describing histopathologic changes in AVM after radiation. The purpose of this study was to examine AVM at various times after gamma-knife radiosurgery in order to determine the mechanism of vessel occlusion after this procedure. Methods: Nine AVM specimens were obtained at autopsy or after surgical excision of residual nidus at times ranging from 10 months to more than 5 years after gamma knife radiosurgery. Formalin fixed, paraffin-embedded sections were examined using routine histopathologic stains: hematoxylin and eosin (H and E), Mallory's phosphotungstic acid-hematoxylin (PTAH), Elastic-van Gieson (EVG), and Hematoxylin-van Gieson (HVG). Additionally, immunohistochemical techniques were used to detect: smooth muscle actin (SMA), Factor VIII, and Type IV collagen. Results: Blood vessels within the AVM show progressive occlusion which correlated with the time interval after radiosurgery. The earliest changes after radiation appear to be damage to and loss of endothelial cells. At this early stage of vascular damage fibrin thrombi are sometimes apparent in the lumen of vessels. With time after radiation there is progressive thickening of the intimal layer, due to proliferation of smooth muscle cells. It is clearly demonstrated, immunohistochemically, that this accumulation of cells within the intimal layer reacts positively for smooth muscle actin, and negatively for Factor VIII (an endothelial cell marker). Using immunohistochemistry it is, also, apparent that these smooth muscle cells are surrounded by an extracellular matrix of Type I collagen, which increases in amount and density over time. Ultimately, vessels are completely occluded by an acellular, amorphous hyalin

Do carbamazepine, gabapentin, or other anticonvulsants exert sufficient radioprotective effects to alter responses from trigeminal neuralgia radiosurgery?

Science.gov (United States)

Flickinger, John C; Kim, Hyun; Kano, Hideyuki; Greenberger, Joel S; Arai, Yoshio; Niranjan, Ajay; Lunsford, L Dade; Kondziolka, Douglas; Flickinger, John C

2012-07-15

Laboratory studies have documented radioprotective effects with carbamazepine. We sought to determine whether carbamazepine or other anticonvulsant/neuroleptic drugs would show significant radioprotective effects in patients undergoing high-dose small-volume radiosurgery for trigeminal neuralgia. We conducted a retrospective review of 200 patients undergoing Gamma Knife (Elekta Instrument AB, Stockholm, Sweden) stereotactic radiosurgery for trigeminal neuralgia between February 1995 and May 2008. We selected patients treated with a maximum dose of 80 Gy with 4-mm diameter collimators, with no previous microvascular decompression, and follow-up ≥6 months (median, 24 months; range, 6-153 months). At the time of radiosurgery, 28 patients were taking no anticonvulsants, 62 only carbamazepine, 35 only gabapentin, 21 carbamazepine plus gabapentin, 17 carbamazepine plus other anticonvulsants, and 9 gabapentin plus other anticonvulsants, and 28 were taking other anticonvulsants or combinations. Pain improvement developed post-radiosurgery in 187 of 200 patients (93.5%). Initial complete pain relief developed in 84 of 200 patients (42%). Post-radiosurgery trigeminal neuropathy developed in 27 of 200 patients (13.5%). We could not significantly correlate pain improvement or initial complete pain relief with use of carbamazepine, gabapentin, or use of any anticonvulsants/neuroleptic drugs or other factors in univariate or multivariate analysis. Post-radiosurgery numbness/paresthesias correlated with the use of gabapentin (1 of 36 patients with gabapentin vs. 7 of 28 without, p = 0.017). In multivariate analysis, decreasing age, purely typical pain, and use of gabapentin correlated (p = 0.008, p = 0.005, and p = 0.021) with lower risks of developing post-radiosurgery trigeminal neuropathy. New post-radiosurgery numbness/paresthesias developed in 3% (1 of 36), 5% (4 of 81), and 13% (23 of 187) of patients on gabapentin alone, with age ≤70 years, and Type 1 typical

Do Carbamazepine, Gabapentin, or Other Anticonvulsants Exert Sufficient Radioprotective Effects to Alter Responses From Trigeminal Neuralgia Radiosurgery?

Energy Technology Data Exchange (ETDEWEB)

Flickinger, John C. [Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA (United States); College of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA (United States); Kim, Hyun [Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA (United States); Kano, Hideyuki [Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA (United States); Greenberger, Joel S.; Arai, Yoshio [Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA (United States); Pittsburgh Cancer Institute, Pittsburgh, PA (United States); Niranjan, Ajay [Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA (United States); Lunsford, L. Dade; Kondziolka, Douglas [Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA (United States); Pittsburgh Cancer Institute, Pittsburgh, PA (United States); Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA (United States); Flickinger, John C., E-mail: flickingerjc@upmc.edu [Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA (United States); Pittsburgh Cancer Institute, Pittsburgh, PA (United States); Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA (United States)

2012-07-15

Purpose: Laboratory studies have documented radioprotective effects with carbamazepine. We sought to determine whether carbamazepine or other anticonvulsant/neuroleptic drugs would show significant radioprotective effects in patients undergoing high-dose small-volume radiosurgery for trigeminal neuralgia. Methods and Materials: We conducted a retrospective review of 200 patients undergoing Gamma Knife (Elekta Instrument AB, Stockholm, Sweden) stereotactic radiosurgery for trigeminal neuralgia between February 1995 and May 2008. We selected patients treated with a maximum dose of 80 Gy with 4-mm diameter collimators, with no previous microvascular decompression, and follow-up {>=}6 months (median, 24 months; range, 6-153 months). At the time of radiosurgery, 28 patients were taking no anticonvulsants, 62 only carbamazepine, 35 only gabapentin, 21 carbamazepine plus gabapentin, 17 carbamazepine plus other anticonvulsants, and 9 gabapentin plus other anticonvulsants, and 28 were taking other anticonvulsants or combinations. Results: Pain improvement developed post-radiosurgery in 187 of 200 patients (93.5%). Initial complete pain relief developed in 84 of 200 patients (42%). Post-radiosurgery trigeminal neuropathy developed in 27 of 200 patients (13.5%). We could not significantly correlate pain improvement or initial complete pain relief with use of carbamazepine, gabapentin, or use of any anticonvulsants/neuroleptic drugs or other factors in univariate or multivariate analysis. Post-radiosurgery numbness/paresthesias correlated with the use of gabapentin (1 of 36 patients with gabapentin vs. 7 of 28 without, p = 0.017). In multivariate analysis, decreasing age, purely typical pain, and use of gabapentin correlated (p = 0.008, p = 0.005, and p = 0.021) with lower risks of developing post-radiosurgery trigeminal neuropathy. New post-radiosurgery numbness/paresthesias developed in 3% (1 of 36), 5% (4 of 81), and 13% (23 of 187) of patients on gabapentin alone, with age

Do Carbamazepine, Gabapentin, or Other Anticonvulsants Exert Sufficient Radioprotective Effects to Alter Responses From Trigeminal Neuralgia Radiosurgery?

International Nuclear Information System (INIS)

Flickinger, John C.; Kim, Hyun; Kano, Hideyuki; Greenberger, Joel S.; Arai, Yoshio; Niranjan, Ajay; Lunsford, L. Dade; Kondziolka, Douglas; Flickinger, John C.

2012-01-01

Purpose: Laboratory studies have documented radioprotective effects with carbamazepine. We sought to determine whether carbamazepine or other anticonvulsant/neuroleptic drugs would show significant radioprotective effects in patients undergoing high-dose small-volume radiosurgery for trigeminal neuralgia. Methods and Materials: We conducted a retrospective review of 200 patients undergoing Gamma Knife (Elekta Instrument AB, Stockholm, Sweden) stereotactic radiosurgery for trigeminal neuralgia between February 1995 and May 2008. We selected patients treated with a maximum dose of 80 Gy with 4-mm diameter collimators, with no previous microvascular decompression, and follow-up ≥6 months (median, 24 months; range, 6–153 months). At the time of radiosurgery, 28 patients were taking no anticonvulsants, 62 only carbamazepine, 35 only gabapentin, 21 carbamazepine plus gabapentin, 17 carbamazepine plus other anticonvulsants, and 9 gabapentin plus other anticonvulsants, and 28 were taking other anticonvulsants or combinations. Results: Pain improvement developed post-radiosurgery in 187 of 200 patients (93.5%). Initial complete pain relief developed in 84 of 200 patients (42%). Post-radiosurgery trigeminal neuropathy developed in 27 of 200 patients (13.5%). We could not significantly correlate pain improvement or initial complete pain relief with use of carbamazepine, gabapentin, or use of any anticonvulsants/neuroleptic drugs or other factors in univariate or multivariate analysis. Post-radiosurgery numbness/paresthesias correlated with the use of gabapentin (1 of 36 patients with gabapentin vs. 7 of 28 without, p = 0.017). In multivariate analysis, decreasing age, purely typical pain, and use of gabapentin correlated (p = 0.008, p = 0.005, and p = 0.021) with lower risks of developing post-radiosurgery trigeminal neuropathy. New post-radiosurgery numbness/paresthesias developed in 3% (1 of 36), 5% (4 of 81), and 13% (23 of 187) of patients on gabapentin alone, with

Proton beam stereotactic radiosurgery of vestibular schwannomas

International Nuclear Information System (INIS)

Harsh, Griffith R.; Thornton, Allan F.; Chapman, Paul H.; Bussiere, Marc R.; Rabinov, James D.; Loeffler, Jay S.

2002-01-01

Purpose: The proton beam's Bragg peak permits highly conformal radiation of skull base tumors. This study, prompted by reports of transient (30% each) and permanent (10% each) facial and trigeminal neuropathy after stereotactic radiosurgery of vestibular schwannomas with marginal doses of 16-20 Gy, assessed whether proton beam radiosurgery using a marginal dose of only 12 Gy could control vestibular schwannomas while causing less neuropathy. Methods and Materials: Sixty-eight patients (mean age 67 years) were treated between 1992 and 1998. The mean tumor volume was 2.49 cm 3 . The dose to the tumor margin (70% isodose line) was 12 Gy. The prospectively specified follow-up consisted of neurologic evaluation and MRI at 6, 12, 24, and 36 months. Results: After a mean clinical follow-up of 44 months and imaging follow-up of 34 months in 64 patients, 35 tumors (54.7%) were smaller and 25 (39.1%) were unchanged (tumor control rate 94%; actuarial control rate 94% at 2 years and 84% at 5 years). Three tumors enlarged: one shrank after repeated radiosurgery, one remained enlarged at the time of unrelated death, and one had not been imaged for 4 years in a patient who remained asymptomatic at last follow-up. Intratumoral hemorrhage into one stable tumor required craniotomy that proved successful. Thus, 97% of tumors required no additional treatment. Three patients (4.7%) underwent shunting for hydrocephalus evident as increased ataxia. Of 6 patients with functional hearing ipsilaterally, 1 improved, 1 was unchanged, and 4 progressively lost hearing. Cranial neuropathies were infrequent: persistent facial hypesthesia (2 new, 1 exacerbated; 4.7%); intermittent facial paresthesias (5 new, 1 exacerbated; 9.4%); persistent facial weakness (2 new, 1 exacerbated; 4.7%) requiring oculoplasty; transient partial facial weakness (5 new, 1 exacerbated; 9.4%), and synkinesis (5 new, 1 exacerbated; 9.4%). Conclusion: Proton beam stereotactic radiosurgery of vestibular schwannomas at the

Radiosurgery in gliomas (middle-line tumors)

International Nuclear Information System (INIS)

Betti, O.O.; Rosler, R.

1989-01-01

The clinical experience is presented obtained from treatment with high-energy linac radiosurgery of 22 patients with stereotactically biopsed gliomas located in middle-line, from thalamus to brain stem and from infundibulum to pineo-tectal regions, during the period 1982-1987. (H.W.). 10 refs

Stereotactic Radiosurgery in the Management of Brain Metastases: An Institutional Retrospective Analysis of Survival

International Nuclear Information System (INIS)

Frazier, James L.; Batra, Sachin; Kapor, Sumit; Vellimana, Ananth; Gandhi, Rahul; Carson, Kathryn A.; Shokek, Ori; Lim, Michael; Kleinberg, Lawrence; Rigamonti, Daniele

2010-01-01

Purpose: The objective of this study was to report our experience with stereotactic radiosurgery performed with the Gamma Knife (GK) in the treatment of patients with brain metastases and to compare survival for those treated with radiosurgery alone with survival for those treated with radiosurgery and whole-brain radiotherapy. Methods and Materials: Prospectively collected demographic and clinical characteristics and treatment and survival data on 237 patients with intracranial metastases who underwent radiosurgery with the GK between 2003 and 2007 were reviewed. Kaplan-Meier and Cox proportional hazards regression analyses were used to compare survival by demographic and clinical characteristics and treatment. Results: The mean age of the patient population was 56 years. The most common tumor histologies were non-small-cell lung carcinoma (34.2%) and breast cancer (13.9%). The median overall survival time was 8.5 months from the time of treatment. The median survival times for patients with one, two/three, and four or more brain metastases were 8.5, 9.4, and 6.7 months, respectively. Patients aged 65 years or greater and those aged less than 65 years had median survival times of 7.8 and 9 months, respectively (p = 0.008). The Karnofsky Performance Score (KPS) at the time of treatment was a significant predictor of survival: those patients with a KPS of 70 or less had a median survival of 2.9 months compared with 10.3 months (p = 0.034) for those with a KPS of 80 or greater. There was no statistically significant difference in survival between patients treated with radiosurgery alone and those treated with radiosurgery plus whole-brain radiotherapy. Conclusions: Radiosurgery with the GK is an efficacious treatment modality for brain metastases. A KPS greater than 70, histology of breast cancer, smaller tumor volume, and age less than 65 years were associated with a longer median survival in our study.

Management of vestibular schwannomas with linear accelerator-based stereotactic radiosurgery: a single center experience.

Science.gov (United States)

Sager, Omer; Beyzadeoglu, Murat; Dincoglan, Ferrat; Demiral, Selcuk; Uysal, Bora; Gamsiz, Hakan; Oysul, Kaan; Dirican, Bahar; Sirin, Sait

2013-01-01

The primary goal of treatment for vestibular schwannoma is to achieve local control without comprimising regional cranial nerve function. Stereotactic radiosurgery has emerged as a viable therapeutic option for vestibular schwannoma. The aim of the study is to report our 15-year single center experience using linear accelerator-based stereotactic radiosurgery in the management of patients with vestibular schwannoma. Between July 1998 and January 2013, 68 patients with unilateral vestibular schwannoma were treated using stereotactic radiosurgery at the Department of Radiation Oncology, Gulhane Military Medical Academy. All patients underwent high-precision stereotactic radiosurgery using a linear accelerator with 6-MV photons. Median follow-up time was 51 months (range, 9-107). Median age was 45 years (range, 20-77). Median dose was 12 Gy (range, 10-13) prescribed to the 85%-95% isodose line encompassing the target volume. Local tumor control in patients with periodic follow-up imaging was 96.1%. Overall hearing preservation rate was 76.5%. Linear accelerator-based stereotactic radiosurgery offers a safe and effective treatment for patients with vestibular schwannoma by providing high local control rates along with improved quality of life through well-preserved hearing function.

Histopathological findings after Leksell gamma knife radiosurgery

International Nuclear Information System (INIS)

Langmann, G.; Dexel, A.; Haller-Schober, E.M.; Koelli, H.; Kleinert, R.

2002-01-01

Radiosurgery for uveal melanoma can achieve tumor control according to clinical studies, yet histopathological proof has not been described. 8 eyes after radiosurgery which had to be removed either to regression failure or severe complications like neovascular glaucoma or persisting retinal detachment were investigated histopathologically and compared to 10 uveal melanomas that were treated by enucleation alone. Uveal melanomas treated with the gamma knife showed tumor necrosis (in more than 50 % total necrosis), a higher number of balloon cells, less number of mitoses and vascular changes (thickening of the vessel's walls, obliteration, thrombosis) which could not be demonstrated in enucleated eyes without irradiation. Leksell gamma knife can cause tumor necrosis and varying degrees of cell death and reduced reproducibility. Vascular changes seem to play a major role in tumor regression. (author)

Cyst formation after radiosurgery for brain arteriovenous malformation treated with cystoperitoneal shunt

International Nuclear Information System (INIS)

Morihiro, Yusuke; Kato, Syoichi; Imoto, Hirochika

2010-01-01

Gamma knife and CyberKnife radiosurgery are well established and less invasive treatments for arteriovenous malformation. Delayed cyst formation is a rare but well-known complication of radiosurgery for arteriovenous malformations. The optimal treatment of cysts forming after radiosurgery remains debatable. We present a case of cyst formation after radiosurgery for brain arteriovenous malformation that was treated with a cystoperitoneal shunt (C-P shunt). A 36-year-old woman presented with left hemiparesis and numbness. Computed tomography (CT) revealed intracranial hemorrhage in the right basal ganglia. Digital subtraction angiography revealed arteriovenous malformation in the brain. Intravascular embolization was performed three times and radiosurgery was performed twice, whereby complete obliteration of the nidus was achieved. Six and a half years later, routine follow-up magnetic resonance imaging revealed cyst formation, and the patient gradually developed left hemiparesis. First, we performed stereotactic cyst aspiration. This initially resulted in a reduction in the size of the cyst and disappearance of left hemiparesis, but within a short time, the cyst increased in size again and there was recurrence of hemiparesis. Therefore, an Ommaya reservoir was established; aspiration of the cyst through this reservoir brought about an initial reduction in cyst size and alleviation of symptoms; however, no further reduction in cyst size or improvement in symptoms could be achieved. Twenty months after the placement of the Ommaya reservoir, we performed a C-P shunt operation. After the operation, further reduction in the cyst size and complete symptomatic recovery were observed. (author)

Measurement of relative dose distributions in stereotactic radiosurgery by the polymer-gel dosimeter

Czech Academy of Sciences Publication Activity Database

Novotný ml., J.; Spěváček, V.; Hrbáček, J.; Judas, L.; Novotný, J.; Dvořák, P.; Tlacháčová, D.; Schmitt, M.; Tintěra, J.; Vymazal, J.; Čechák, T.; Michálek, Jiří; Přádný, Martin; Liščák, R.

2004-01-01

Roč. 5, - (2004), s. 225-235 ISSN 1024-2651. [International Stereotactic Radiosurgery Society Meeting /6./. Kyoto, 22.06.2003-26.06.2003] R&D Projects: GA MZd NC7460 Institutional research plan: CEZ:AV0Z4050913 Keywords : stereotactic radiosurgery * polymer-gel dosimeter Subject RIV: FD - Oncology ; Hematology

Report of AAPM TG 135: quality assurance for robotic radiosurgery.

Science.gov (United States)

Dieterich, Sonja; Cavedon, Carlo; Chuang, Cynthia F; Cohen, Alan B; Garrett, Jeffrey A; Lee, Charles L; Lowenstein, Jessica R; d'Souza, Maximian F; Taylor, David D; Wu, Xiaodong; Yu, Cheng

2011-06-01

The task group (TG) for quality assurance for robotic radiosurgery was formed by the American Association of Physicists in Medicine's Science Council under the direction of the Radiation Therapy Committee and the Quality Assurance (QA) Subcommittee. The task group (TG-135) had three main charges: (1) To make recommendations on a code of practice for Robotic Radiosurgery QA; (2) To make recommendations on quality assurance and dosimetric verification techniques, especially in regard to real-time respiratory motion tracking software; (3) To make recommendations on issues which require further research and development. This report provides a general functional overview of the only clinically implemented robotic radiosurgery device, the CyberKnife. This report includes sections on device components and their individual component QA recommendations, followed by a section on the QA requirements for integrated systems. Examples of checklists for daily, monthly, annual, and upgrade QA are given as guidance for medical physicists. Areas in which QA procedures are still under development are discussed.

Clinical outcomes of gamma knife radiosurgery in the salvage treatment of patients with recurrent high-grade glioma.

Science.gov (United States)

Elaimy, Ameer L; Mackay, Alexander R; Lamoreaux, Wayne T; Demakas, John J; Fairbanks, Robert K; Cooke, Barton S; Lamm, Andrew F; Lee, Christopher M

2013-12-01

Previously published randomized evidence did not report a survival advantage for patients diagnosed with grade IV glioma who were treated with stereotactic radiosurgery followed by external beam radiation therapy and chemotherapy when compared to patients treated with external beam radiation therapy and chemotherapy alone. In recent years, gamma knife radiosurgery has become increasingly popular as a salvage treatment modality for patients diagnosed with recurrent high-grade glioma. The purpose of this article is to review the efficacy of gamma knife radiosurgery for patients who suffer from this malignancy. Retrospective, prospective, and randomized clinical studies published between the years 2000 and 2012 analyzing gamma knife radiosurgery for patients with high-grade glioma were reviewed. After assessing patient age, Karnofsky performance status, tumor histology, and extent of resection, gamma knife radiosurgery is a viable, minimally invasive treatment option for patients diagnosed with recurrent high-grade glioma. The available prospective and retrospective evidence suggests that gamma knife radiosurgery provides patients with a high local tumor control rate and a median survival after tumor recurrence ranging from 13 to 26 months. Gamma knife radiosurgery followed by chemotherapy for recurrent high-grade glioma may provide select patients with increased levels of survival. However, further investigation into this matter is needed due to the limited number of published reports. Additional clinical research is also needed to analyze the efficacy and radiation-related toxicities of fractionated gamma knife radiosurgery due to its potential to limit treatment-associated morbidity. Gamma knife radiosurgery is a safe and effective treatment option for select patients diagnosed with recurrent high-grade glioma. Although treatment outcomes have improved, further evidence in the form of phase III randomized trials is needed to assess the durability of treating

Outcomes of Diffusion Tensor Tractography-Integrated Stereotactic Radiosurgery

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Koga, Tomoyuki, E-mail: kouga-tky@umin.ac.jp [Department of Neurosurgery, University of Tokyo Hospital, Tokyo (Japan); Maruyama, Keisuke; Kamada, Kyousuke; Ota, Takahiro; Shin, Masahiro [Department of Neurosurgery, University of Tokyo Hospital, Tokyo (Japan); Itoh, Daisuke [Department of Radiology, University of Tokyo Hospital, Tokyo (Japan); Kunii, Naoto [Department of Neurosurgery, University of Tokyo Hospital, Tokyo (Japan); Ino, Kenji; Terahara, Atsuro; Aoki, Shigeki; Masutani, Yoshitaka [Department of Radiology, University of Tokyo Hospital, Tokyo (Japan); Saito, Nobuhito [Department of Neurosurgery, University of Tokyo Hospital, Tokyo (Japan)

2012-02-01

Purpose: To analyze the effect of use of tractography of the critical brain white matter fibers created from diffusion tensor magnetic resonance imaging on reduction of morbidity associated with radiosurgery. Methods and Materials: Tractography of the pyramidal tract has been integrated since February 2004 if lesions are adjacent to it, the optic radiation since May 2006, and the arcuate fasciculus since October 2007. By visually confirming the precise location of these fibers, the dose to these fiber tracts was optimized. One hundred forty-four consecutive patients with cerebral arteriovenous malformations who underwent radiosurgery with this technique between February 2004 and December 2009 were analyzed. Results: Tractography was prospectively integrated in 71 of 155 treatments for 144 patients. The pyramidal tract was visualized in 45, the optic radiation in 22, and the arcuate fasciculus in 13 (two tracts in 9). During the follow-up period of 3 to 72 months (median, 23 months) after the procedure, 1 patient showed permanent worsening of pre-existing dysesthesia, and another patient exhibited mild transient hemiparesis 12 months later but fully recovered after oral administration of corticosteroid agents. Two patients had transient speech disturbance before starting integration of the arcuate fasciculus tractography, but no patient thereafter. Conclusion: Integrating tractography helped prevent morbidity of radiosurgery in patients with brain arteriovenous malformations.

Stereotactic gamma radiosurgery of pineal and related tumors

International Nuclear Information System (INIS)

Kobayashi, Tatsuya; Mori, Yoshimasa; Yamada, Yasushi; Kida, Yoshihisa

2001-01-01

The role of gamma radiosurgery as an additional therapy after conventional treatments for pineal and related tumors was studied in 30 out of 33 cases with a mean follow-up of 23.3 months. Overall results showed that complete response (CR) was obtained in 8 cases (26.7%) and response rate was 73.3%. However, enlargement of the tumors was noted in 8 cases, of which 7 (23.3%) died of tumor progression (PG). Germinomas and pineocytomas showed higher response and control rates of 100%, and no tumor enlargement or death occurred after gamma knife treatment. In germinoma with STGC (syncytiotrophoblastic giant cell) which has been thought to have intermediate prognosis, two cases showed partial response (PR), but another died from progression of the disease. Malignant germ cell tumors and pineoblastomas showed unfavorable response and prognosis; the response and progression rates were 50%. However, complete response was obtained in 3 cases (25%) after gamma radiosurgery. Gamma knife was the initial treatment in three cases without pathological diagnosis in which one obtained CR and two showed partial response (PR). Stereotactic gamma radiosurgery is expected to be an effective and novel treatment for pineal and related tumors not only as an adjuvant, but also as an initial therapy. (author)

Effects of gamma knife radiosurgery for pediatric craniopharyngiomas

International Nuclear Information System (INIS)

Tanaka, Takayuki; Kobayashi, Tatsuya; Kida, Yoshihisa

1996-01-01

Seven cases of pediatric craniopharyngiomas have been treated by gamma knife and followed-up for a mean 24.1 months between May, 1991 and March, 1995. They included 4 boys and 3 girls with a mean age of 8.9 years. Initial signs and symptoms were: headaches in 2 cases, decrease in visual acuity in 6 cases, visual field deficit in 5 cases, hypopituitary function in 5 cases, and diabetes insipidus in one case. Prior to the radiosurgery, surgical therapy had been performed in 7 cases, conventional radiotherapy in one case, and chemotherapy in one case. Tumor were located in the chiasmal region in 3 cases and the suprasellar region in 4 cases. Mean tumor diameter was 18.5 mm. Mean and marginal irradiation dosages were 25.9 Gy and 13.4 Gy. Repeated MRI indicated marked shrinkage of tumors was obtained in all 7 cases. Follow up showed neurological signs and symptoms improved in 3 cases and remained unchanged in 4 cases, without any side-effects. Hormonal study indicated TSH decreased about one year after gamma knife radiosurgery. It is considered that gamma knife radiosurgery will be a safe and effective treatment for pediatric craniopharyngiomas in combination with microsurgery. (author)

Fractionated radiosurgery for 9L gliosarcoma in the rat brain

International Nuclear Information System (INIS)

Kim, Jae Ho; Khil, Mark S.; Kolozsvary, Andrew; Gutierrez, Jorge A.; Brown, Stephen L.

1999-01-01

Purpose: Fractionated radiosurgery is being carried out in the clinic to improve the therapeutic ratio of single-dose radiosurgery using various fractionation schemes. Because there is a paucity of experimental radiobiological data in the literature on the tumor response and late-responding normal tissue of critical intracranial structures to radiosurgery, the present animal study was designed to compare the response following a single high dose of radiation with that obtained from calculated fractionated doses of radiosurgery. Methods and Materials: Male Fischer rats with 9L gliosarcoma growing in their brains were stereotactically irradiated and assayed for the tumor control rate and brain tissue damage. The radiation dose needed for 50% tumor control (TCD 50 ) was used as the endpoint of the efficacy of radiosurgery. Normal brain damage was measured histologically following a period of time over 270 days. Histological evaluation included hematoxylin-eosin (H and E), Luxol fast blue and periodic acid Schiff (LFB/PAS) for the presence of myelin and glial fibrillary acidic protein (GFAP) for the assessment of astrocytic re-activity. The optical density of optic nerves and chiasms staining with LFB/PAS was quantitatively measured using a computer image analysis to assess the magnitude of demyelination. Results: Radiosurgery (RS) was found to be more effective in curing small tumors than large tumors. The dose required to control 50% of the tumored animals for 120 days was 24, 31, and 40 Gy for 2-, 6-, and 12-day-old tumors, respectively. Using 12-day-old brain tumors, two fractions of 23.5 Gy and three fractions of 18.5 Gy were found to be equivalent to the single dose of 35 Gy for tumor control. For normal brain damages, the visual pathways including optic nerves and chiasm were found to be highly radiosensitive structures. A single dose of 35 Gy produced 100% severe optic neuropathy. The fractionated RS regimens spared substantial optic nerve damage. Conclusion

Radiosurgery of epidermoid tumors with gamma knife. Possiblity of radiosurgical nerve decompression

International Nuclear Information System (INIS)

Kida, Yoshihisa; Yoshimoto, Masayuki; Hasegawa, Toshinori; Fujitani, Shigeru

2006-01-01

Long-term results of radiosurgery for epidermoid tumors are reported. There are 7 cases including 2 males and 5 females, ages ranging from 6 to 46 (mean: 33.3 years). At radiosurgery whole tumor was covered in 4 cases and partially covered in 3 cases in attempting to relieve cranial nerve signs like trigeminal neuralgia and facial spasm. The mean maximum and marginal doses were 25.6 Gy and 14.6 Gy respectively. In the mean follow-up of 52.7 months, all the tumors showed good tumor control without any progression and tumor shrinkage has been confirmed in 2 out of the 7 cases. Symptomatic trigeminal neuralgia improved or disappeared in all 4 cases and facial spasm disappeared in one. No neurological deterioration was found in any of the cases after the treatment. In conclusion, it is apparent that epidermoid tumors do respond well to radiosurgery and the accompanying hyperactive dysfunction of cranial nerves is significantly improved by gamma knife treatment with either entire or partial tumor coverage. Therefore the radiosurgical nerve decompression for epidermoid tumor seems to be achieved by gamma-radiosurgery. (author)

Resampling: An optimization method for inverse planning in robotic radiosurgery

International Nuclear Information System (INIS)

Schweikard, Achim; Schlaefer, Alexander; Adler, John R. Jr.

2006-01-01

By design, the range of beam directions in conventional radiosurgery are constrained to an isocentric array. However, the recent introduction of robotic radiosurgery dramatically increases the flexibility of targeting, and as a consequence, beams need be neither coplanar nor isocentric. Such a nonisocentric design permits a large number of distinct beam directions to be used in one single treatment. These major technical differences provide an opportunity to improve upon the well-established principles for treatment planning used with GammaKnife or LINAC radiosurgery. With this objective in mind, our group has developed over the past decade an inverse planning tool for robotic radiosurgery. This system first computes a set of beam directions, and then during an optimization step, weights each individual beam. Optimization begins with a feasibility query, the answer to which is derived through linear programming. This approach offers the advantage of completeness and avoids local optima. Final beam selection is based on heuristics. In this report we present and evaluate a new strategy for utilizing the advantages of linear programming to improve beam selection. Starting from an initial solution, a heuristically determined set of beams is added to the optimization problem, while beams with zero weight are removed. This process is repeated to sample a set of beams much larger compared with typical optimization. Experimental results indicate that the planning approach efficiently finds acceptable plans and that resampling can further improve its efficiency

Gamma Knife® radiosurgery for trigeminal neuralgia.

Science.gov (United States)

Yen, Chun-Po; Schlesinger, David; Sheehan, Jason P

2011-11-01

Trigeminal neuralgia is characterized by a temporary paroxysmal lancinating facial pain in the trigeminal nerve distribution. The prevalence is four to five per 100,000. Local pressure on nerve fibers from vascular loops results in painful afferent discharge from an injured segment of the fifth cranial nerve. Microvascular decompression addresses the underlying pathophysiology of the disease, making this treatment the gold standard for medically refractory trigeminal neuralgia. In patients who cannot tolerate a surgical procedure, those in whom a vascular etiology cannot be identified, or those unwilling to undergo an open surgery, stereotactic radiosurgery is an appropriate alternative. The majority of patients with typical facial pain will achieve relief following radiosurgical treatment. Long-term follow-up for recurrence as well as for radiation-induced complications is required in all patients undergoing stereotactic radiosurgery for trigeminal neuralgia.

Long-term follow-up of patients with surgical intractable acromegaly after linear accelerator radiosurgery

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Jiun-Lin Yan

2013-07-01

Conclusion: In comparison to other radiosurgery modalities, LINAC radiosurgery also provides a satisfactory outcome. SRS has maximum effect over the first 2 years and stabilizes after 7.5 years. Moreover, SRS elicits long-term biochemical effects and requires longer follow-up for better biochemical remission.

Stereotaxic radiosurgery for therapy of arterivenous malformation of the brain

International Nuclear Information System (INIS)

Beraha, J.; Feriancic, C.V.; Scaff, L.A.M.

1987-01-01

Since march 1983 we are attempting for the first time in Brazil to develop improvements on stereotactic radiosurgery techniques. We have been using the multifocal irradiation method attaching to this purpose the Barcia IV stereotactic frame to a 4 MV linear accelerator. We show details about the centralization technique and the security patterns in our system. From October 1983 to November 1986, 25 patients with arteriovenous malformations of the brain were submitted to a radiosurgery treatment in our service. Good results obtained on the follow-up from one to three years are analysed. (author)

Tolerance of cranial nerves of the cavernous sinus to radiosurgery

International Nuclear Information System (INIS)

Tishler, R.B.; Loeffler, J.S.; Alexander, E. III; Kooy, H.M.; Lunsford, L.D.; Duma, C.; Flickinger, J.C.

1993-01-01

Stereotactic radiosurgery is becoming a more accepted treatment option for benign, deep seated intracranial lesions. However, little is known about the effects of large single fractions of radiation on cranial nerves. This study was undertaken to assess the effect of radiosurgery on the cranial nerves of the cavernous sinus. The authors examined the tolerance of cranial nerves (II-VI) following radiosurgery for 62 patients (42/62 with meningiomas) treated for lesions within or near the cavernous sinus. Twenty-nine patients were treated with a modified 6 MV linear accelerator (Joint Center for Radiation Therapy) and 33 were treated with the Gamma Knife (University of Pittsburgh). Three-dimensional treatment plans were retrospectively reviewed and maximum doses were calculated for the cavernous sinus and the optic nerve and chiasm. Median follow-up was 19 months (range 3-49). New cranial neuropathies developed in 12 patients from 3-41 months following radiosurgery. Four of these complications involved injury to the optic system and 8 (3/8 transient) were the result of injury to the sensory or motor nerves of the cavernous sinus. There was no clear relationship between the maximum dose to the cavernous sinus and the development of complications for cranial nerves III-VI over the dose range used (1000-4000 cGy). For the optic apparatus, there was a significantly increased incidence of complications with dose. Four of 17 patients (24%) receiving greater than 800 cGy to any part of the optic apparatus developed visual complications compared with 0/35 who received less than 800 cGy (p = 0.009). Radiosurgery using tumor-controlling doses of up to 4000 cGy appears to be a relatively safe technique in treating lesions within or near the sensory and motor nerves (III-VI) of the cavernous sinus. The dose to the optic apparatus should be limited to under 800 cGy. 21 refs., 4 tabs

Large central lesions compressing the hypothalamus and brainstem. Operative approaches and combination treatment with radiosurgery

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Inoue, Hiroshi K.; Negishi, Masatoshi; Kohga, Hideaki; Hirato, Masafumi; Ohye, Chihiro [Gunma Univ., Maebashi (Japan). School of Medicine; Shibazaki, Tohru

1998-09-01

A major aim of minimally invasive neurosurgery is to preserve function in the brain and cranial nerves. Based on previous results of radiosurgery for central lesions (19 craniopharyngiomas, 46 pituitary adenomas, 9 meningeal tumors), combined micro- and/or radiosurgery was applied for large lesions compressing the hypothalamus and/or brainstem. A basal interhemispheric approach via superomedial orbitotomy or a transcallosal-transforaminal approach was used for these large tumors. Tumors left behind in the hypothalamus or cavernous sinus were treated with radiosurgery using a gamma unit. Preoperative hypothalamo-pituitary functions were preserved in most of these patients. Radiosurgical results were evaluated in patients followed for more than 2 years after treatment. All 9 craniopharyngiomas decreased in size after radiosurgery, although a second treatment was required in 4 patients. All 20 pituitary adenomas were stable or decreased in size and 5 of 7 functioning adenomas showed normalized values of hormones in the serum. All 3 meningeal tumors were stable or decreased in size after treatment. No cavernous sinus symptoms developed after radiosurgery. We conclude that combined micro- and radio-neurosurgery is an effective and less invasive treatment for large central lesions compressing the hypothalamus and brainstem. (author)

Large central lesions compressing the hypothalamus and brainstem. Operative approaches and combination treatment with radiosurgery

International Nuclear Information System (INIS)

Inoue, Hiroshi K.; Negishi, Masatoshi; Kohga, Hideaki; Hirato, Masafumi; Ohye, Chihiro; Shibazaki, Tohru

1998-01-01

A major aim of minimally invasive neurosurgery is to preserve function in the brain and cranial nerves. Based on previous results of radiosurgery for central lesions (19 craniopharyngiomas, 46 pituitary adenomas, 9 meningeal tumors), combined micro- and/or radiosurgery was applied for large lesions compressing the hypothalamus and/or brainstem. A basal interhemispheric approach via superomedial orbitotomy or a transcallosal-transforaminal approach was used for these large tumors. Tumors left behind in the hypothalamus or cavernous sinus were treated with radiosurgery using a gamma unit. Preoperative hypothalamo-pituitary functions were preserved in most of these patients. Radiosurgical results were evaluated in patients followed for more than 2 years after treatment. All 9 craniopharyngiomas decreased in size after radiosurgery, although a second treatment was required in 4 patients. All 20 pituitary adenomas were stable or decreased in size and 5 of 7 functioning adenomas showed normalized values of hormones in the serum. All 3 meningeal tumors were stable or decreased in size after treatment. No cavernous sinus symptoms developed after radiosurgery. We conclude that combined micro- and radio-neurosurgery is an effective and less invasive treatment for large central lesions compressing the hypothalamus and brainstem. (author)

A multi-institutional analysis of complication outcomes after arteriovenous malformation radiosurgery

International Nuclear Information System (INIS)

Flickinger, John C.; Kondziolka, Douglas; Lunsford, L. Dade; Pollock, Bruce E.; Yamamoto, Masaaki; Gorman, Deborah A.; Schomberg, Paula J.; Sneed, Patricia; Larson, David; Smith, Vernon; McDermott, Michael W.; Miyawaki, Lloyd; Chilton, Jonathan; Morantz, Robert A.; Young, Byron; Jokura, Hidefumi; Liscak, Roman

1999-01-01

Purpose: To better understand radiation complications of arteriovenous malformation (AVM) radiosurgery and factors affecting their resolution. Methods and Materials: AVM patients (102/1255) who developed neurological sequelae after radiosurgery were studied. The median AVM marginal dose (D min ) was 19 Gy (range: 10-35). The median volume was 5.7 cc (range: 0.26-143). Median follow-up was 34 months (range: 9-140). Results: Complications consisted of 80/102 patients with evidence of radiation injury to the brain parenchyma (7 also with cranial nerve deficits, 12 also with seizures, 5 with cyst formation), 12/102 patients with isolated cranial neuropathies, and 10/102 patients with only new or worsened seizures. Severity was classified as minimal in 39 patients, mild in 40, disabling in 21, and fatal in 2 patients. Symptoms resolved completely in 42 patients for an actuarial resolution rate of 54% ± 7% at 3 years post-onset. Multivariate analysis identified significantly greater symptom resolution in patients with no prior history of hemorrhage (p = 0.01, 66% vs. 41%), and in patients with symptoms of minimal severity: headache or seizure as the only sequelae of radiosurgery (p < 0.0001, 88% vs. 34%). Conclusion: Late sequelae of radiosurgery manifest in varied ways. Further long-term studies of these problems are needed that take into account symptom severity and prior hemorrhage history

The Physician Tendency in Stereotactic Radiosurgery Dose Prescription in Benign Intracranial Tumor at dr. Cipto Mangunkusumo National Hospital, Jakarta

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Henry Kodrat

2016-09-01

Full Text Available Stereotactic radiosurgery (SRS is one of the treatment modalities for benign intra-cranial tumor, especiallyfor the tumor located next to the critical neural structure. The prescribed dose for radiosurgery depends onthe maximal tumor diameter and surrounding normal tissue tolerance dose. This cross sectional study wasconducted to evaluate the physician’s tendency in radiosurgery dose prescription. We observed treatmentplanning data of 32 patients with benign intra-cranial tumor, which had been treated with SRS at Dr. CiptoMangunkusumo National Hospital in 2009-2010. The peripheral dose, organ at risk (OAR dose limitiationand maximum tumor diameter were recorded. We compared our SRS dose with dose limitation, whichallowed safer dosing based on maximal tumor diameter perspective and the nearest OAR dose constraint.From maximal tumor diameter perspective, we prescribed mean±SD radiosurgery doses, which were11.63±2.21Gy, 10.21±1.29Gy and 9.88±1.07Gy for the tumor size ≤2cm, 2.01-3cm and 3,01-4cm respectively.Our radiosurgery dose was the lowest than dose limitation based on the nearest OAR perspective, followedby maximal tumor diameter perspective. It was concluded that radiosurgery dose had the tendency to beinfluenced by surrounding healthy tissue tolerance rather than maximal tumor diameter. Keywords: stereotactic, radiosurgery, benign tumor, dose.   Kecenderungan Dokter dalam Menentukan Dosis StereotacticRadiosurgery untuk Tumor Jinak Intrakranial diRSUP Nasional dr. Cipto Mangunkusumo, Jakarta Abstrak Stereotactic radiosurgery (SRS merupakan salah satu modalitas pengobatan tumor jinak intra-kranialterutama untuk tumor yang berdekatan dengan struktur saraf penting. Penentuan dosis pada radiosurgerytergantung pada diameter tumor maksimal dan dosis toleransi jaringan sehat sekitarnya. Penelitian inidilakukan untuk mengevaluasi kecenderungan dokter dalam menentukan dosis radiosurgery. Penelitian crosssectional ini mengevaluasi data

Stereotactic radiosurgery planning with ictal SPECT images

International Nuclear Information System (INIS)

Ackerly, T.; RMIT University, Bundoora, VIC; Geso, M.; O'Keefe, G.; Smith, R.

2004-01-01

This paper is motivated by a clinical requirement to utilise ictal SPECT images for target localisation in stereotactic radiosurgery treatment planning using the xknife system which only supports CT and MRI images. To achieve this, the SPECT images were converted from raw (pixel data only) format into a part 10 compliant DICOM CT fileset. The minimum requirements for the recasting of a raw format image as DICOM CT or MRI data set are described in detail. The method can be applied to the importation of raw format images into any radiotherapy treatment planning system that supports CT or MRI import. It is demonstrated that the combination of the low spatial resolution SPECT images, depicting functional information, with high spatial resolution MRI images, which show the structural information, is suitable for stereotactic radiosurgery treatment planning. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

Technical and anatomical aspects of novalis stereotactic radiosurgery sphenopalatine ganglionectomy

International Nuclear Information System (INIS)

De Salles, Antonio A.F.; Gorgulho, Alessandra; Golish, S. Raymond Ph.D.; Medin, Paul M.; Malkasian, Dennis; Solberg, Timothy D.; Selch, Michael T.

2006-01-01

Background: Several techniques have been applied for destruction of the sphenopalatine ganglion to control cluster headache and ocular pain with sympathetic component. Cluster headache has responded to radiofrequency ablation or phenol destruction. Radiosurgery of the sphenopalatine ganglion is promising due to the excellent visualization of the target on magnetic resonance imaging (MRI), computed tomography (CT), and skull X-rays. Material and Methods: Six patients and one cadaver head were analyzed in this study. The cadaver-head dissection confirmed the location of the sphenopalatine ganglion on X-rays and CT imaging. One patient undergoing radiofrequency sphenopalatine ablation participated for confirmation of the location of the ganglion on plain X-rays. Five patients received radiosurgery of the sphenopalatine ganglion. One patient had classic unilateral cluster headache. Two patients had neuropathic pain and 1 had bilateral migrainous neuralgia. The fifth patient had bilateral atypical facial pain. All received a single maximal dose of 90 Gy with a 5- or 7.5-mm circular collimator. MRI, CT, and skull X-rays identified and confirmed the target. Results: The sphenopalatine fossa is seen in the skull X-ray as an inverse tear drop just caudal to the sphenoid sinus. This location is readily correlated to the CT target by the stereotactic coordinates and confirmed with the presence of the ganglion visualized in the MRI scan. Only the patient with cluster headache experienced lasting pain relief. Conclusion: Multiple imaging modalities confirmed the location of the sphenopalatine ganglion for radiosurgery. The procedure was performed safely with CT and MRI fusion. Radiosurgery was significantly beneficial only on classic cluster headache

Bevacizumab for the Treatment of Gammaknife Radiosurgery-Induced Brain Radiation Necrosis.

Science.gov (United States)

Ma, Yifang; Zheng, Chutian; Feng, Yiping; Xu, Qingsheng

2017-09-01

Radiation necrosis is one of the complications of Gammaknife radiosurgery. The traditional treatment of radiation necrosis carries a high risk of failure, Bevacizumab is an antiangiogenic monoclonal antibody against vascular endothelial growth factor, a known mediator of cerebral edema. It can be used to successfully treat brain radiation necrosis. Two patients with a history of small cell lung cancer presented with metastatic disease to the brain. They underwent Gammaknife radiosurgery to brain metastases. Several months later, magnetic resonance imaging showed radiation necrosis with significant surrounding edema. The patients had a poor response to treatment with dexamethasone. They were eventually treated with bevacizumab (5 mg/kg every 2 weeks, 7.5 mg/kg every 3 weeks, respectively), and the treatment resulted in significant clinical and radiographic improvement. Bevacizumab can be successfully used to treat radiation necrosis induced by Gammaknife radiosurgery in patients with cerebral metastases. It is of particular benefit in patients with poor reaction to corticosteroids and other medications.

Atlas-based functional radiosurgery: Early results

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Stancanello, J.; Romanelli, P.; Pantelis, E.; Sebastiano, F.; Modugno, N. [Politecnico di Milano, Bioengineering Department and NEARlab, Milano, 20133 (Italy) and Siemens AG, Research and Clinical Collaborations, Erlangen, 91052 (Germany); Functional Neurosurgery Deptartment, Neuromed IRCCS, Pozzilli, 86077 (Italy); CyberKnife Center, Iatropolis, Athens, 15231 (Greece); Functional Neurosurgery Deptartment, Neuromed IRCCS, Pozzilli, 86077 (Italy)

2009-02-15

Functional disorders of the brain, such as dystonia and neuropathic pain, may respond poorly to medical therapy. Deep brain stimulation (DBS) of the globus pallidus pars interna (GPi) and the centromedian nucleus of the thalamus (CMN) may alleviate dystonia and neuropathic pain, respectively. A noninvasive alternative to DBS is radiosurgical ablation [internal pallidotomy (IP) and medial thalamotomy (MT)]. The main technical limitation of radiosurgery is that targets are selected only on the basis of MRI anatomy, without electrophysiological confirmation. This means that, to be feasible, image-based targeting must be highly accurate and reproducible. Here, we report on the feasibility of an atlas-based approach to targeting for functional radiosurgery. In this method, masks of the GPi, CMN, and medio-dorsal nucleus were nonrigidly registered to patients' T1-weighted MRI (T1w-MRI) and superimposed on patients' T2-weighted MRI (T2w-MRI). Radiosurgical targets were identified on the T2w-MRI registered to the planning CT by an expert functional neurosurgeon. To assess its feasibility, two patients were treated with the CyberKnife using this method of targeting; a patient with dystonia received an IP (120 Gy prescribed to the 65% isodose) and a patient with neuropathic pain received a MT (120 Gy to the 77% isodose). Six months after treatment, T2w-MRIs and contrast-enhanced T1w-MRIs showed edematous regions around the lesions; target placements were reevaluated by DW-MRIs. At 12 months post-treatment steroids for radiation-induced edema and medications for dystonia and neuropathic pain were suppressed. Both patients experienced significant relief from pain and dystonia-related problems. Fifteen months after treatment edema had disappeared. Thus, this work shows promising feasibility of atlas-based functional radiosurgery to improve patient condition. Further investigations are indicated for optimizing treatment dose.

The usefulness of adjuvant therapy using gamma knife radiosurgery for the recurrent or residual nonfunctioning pituitary adenomas

International Nuclear Information System (INIS)

Iwai, Yoshiyasu; Yamanaka, Kazuhiro; Yoshioka, Katsunobu; Yoshimura, Masaki; Honda, Yuji; Matsusaka, Yasuhiro; Komiyama, Masaki; Yasui, Toshihiro

2005-01-01

We evaluated the treatment results of nonfunctioning pituitary adenomas in the era of radiosurgery. Between January 1994 and December 2003, we operated on 44 patients with nonfunctioning pituitary adenomas. Forty-three patients were operated on by transsphenoidal surgery and one patient was operated on by the transcranial approach. Total removal was able to be achieved in 13 patients (30%). Gamma knife radiosurgery was performed for residual tumor in 26 patients and for recurrence in 2 patients. The mean tumor diameter at the gamma knife radiosurgery was 18.2 mm (7.9 to 26.3 mm). The treatment dose was a mean of 12.3 Gy (8 to 16 Gy) to the tumor margin. The mean follow-up period after radiosurgery was 36.4 months. Tumor growth control was able to be achieved in 26 patients (93%). Two patients (7%) required adrenal and thyroid hormonal replacement during the follow-up period after radiosurgery due to radiation-induced endocrinopathy. None of the patients suffered from new cranial nerve deficits. This included optic neuropathy. Surgical resection using transsphenoidal surgery and subsequent gamma knife radiosurgery for residual and recurrent tumor proved to have a highly effective tumor growth control rate, and maintained the quality of life in patients with nonfunctioning pituitary adenomas. (author)

The American Society for Therapeutic Radiology and Oncology (ASTRO) evidence-based review of the role of radiosurgery for brain metastases

International Nuclear Information System (INIS)

Mehta, Minesh P.; Tsao, May N.; Whelan, Timothy J.; Morris, David E.; Hayman, James A.; Flickinger, John C.; Mills, Michael; Rogers, C. Leland; Souhami, Luis

2005-01-01

Purpose: To systematically review the evidence for the use of stereotactic radiosurgery in adult patients with brain metastases. Methods: Key clinical questions to be addressed in this evidence-based review were identified. Outcomes considered were overall survival, quality of life or symptom control, brain tumor control or response and toxicity. MEDLINE (1990-2004 June Week 2), CANCERLIT (1990-2003), CINAHL (1990-2004 June Week 2), EMBASE (1990-2004 Week 25), and the Cochrane library (2004 issue 2) databases were searched using OVID. In addition, the Physician Data Query clinical trials database, the proceedings of the American Society of Clinical Oncology (ASCO) (1997-2004), ASTRO (1997-2004), and the European Society of Therapeutic Radiology and Oncology (ESTRO) (1997-2003) were searched. Data from the literature search were reviewed and tabulated. This process included an assessment of the level of evidence. Results: For patients with newly diagnosed brain metastases, managed with whole-brain radiotherapy alone vs. whole-brain radiotherapy and radiosurgery boost, there were three randomized controlled trials, zero prospective studies, and seven retrospective series (which satisfied inclusion criteria). For patients with up to three (<4 cm) newly diagnosed brain metastases (and in one study up to four brain metastases), radiosurgery boost with whole-brain radiotherapy significantly improves local brain control rates as compared with whole-brain radiotherapy alone (Level I-III evidence). In one large randomized trial, survival benefit with whole-brain radiotherapy was observed in patients with single brain metastasis. In this trial, an overall increased ability to taper down on steroid dose and an improvement in Karnofsky performance status was seen in patients who were treated with radiosurgery boost as compared with patients treated with whole-brain radiotherapy alone. However, Level I evidence regarding overall quality of life outcomes using a validated

Acceptance, commissioning and quality control in radiosurgery

International Nuclear Information System (INIS)

Toreti, Dalila Luzia

2009-01-01

Stereotactic Radiosurgery is a treatment technique that uses narrow beams of radiation focused with great accuracy in a small lesion. The introduction of micro multi leaf collimators (mMLC) allows this technique to reach a higher degree of dose conformation of the target lesion allowing a smaller irradiation of critical structures and normal tissues. This paper presents the results of the acceptance tests and commissioning of a Varian 6EX linear accelerator dedicated to radiosurgery associated with the BrainLab micro multi leaf collimator installed in the Hospital das Clinicas da Faculdade de Medicina da USP (HC-FMUSP) and establish feasible quality assurance program for the services that employ this special technique. The results of the acceptance tests were satisfactory and are willing with the specifications provided by the manufacturer and the commissioning tests were within the international recommendations. The tests and measures that are part of quality control process should be specific to each treatment unit, and the need, frequency and levels of tolerance

Stereotactic radiosurgery with an upper partial denture

International Nuclear Information System (INIS)

Tayama, Shusaku; Kunieda, Etsuo; Takeda, Atsushi; Takeda, Toshiaki; Oku, Yohei

2009-01-01

A 54-year-old male with partial denture underwent stereotactic radiosurgery with an infrared camera-guided system for a metastatic brain tumor arising from lung cancer. Although this method utilizes a biteplate mounted on the upper jaw to detect head movement, the patient only had four teeth in his upper jaw. In order to stabilize the biteplate, the maxillary denture was fixed to the biteplate with an autopolymerizing resin. In addition, the rest-occlusal position of the lower jaw was impressed on the inferior surface of the biteplate with an autopolymerizing resin. To assess reproducibility and stability, the distance between the left and right incus and left and right markers was measured during pre-planning, as well as before and after stereotactic irradiation. Wearing the biteplate ensures the accuracy of radiotherapy planning for the implementation of radiosurgery in patients who have many maxillary teeth missing. However, a large degree of error was observed when the biteplate was removed. (author)

Assessment of neuropsychological changes in patients with arteriovenous malformation (AVM) after radiosurgery

International Nuclear Information System (INIS)

Wenz, Frederik; Steinvorth, Sarah; Wildermuth, Susanne; Lohr, Frank; Fuss, Martin; Debus, Juergen; Essig, Marco; Hacke, Werner; Wannenmacher, Michael

1998-01-01

Purpose: The purpose of this study was to investigate neuropsychological effects of radiosurgery in patients with cerebral arteriovenous malformation (AVM), with special focus on attention and memory. This report describes the study setup and presents the first results during a follow-up of up to 1 year. Materials and Methods: Seventy-nine patients were studied before, acutely after radiosurgery, and during the regular follow-up (subacute phase: Weeks 6-12, chronic phase: Months 6-12). Radiosurgery was performed using a modified linear accelerator (minimum doses to the target volume: 15-22 Gy, median 20 Gy). Estimated whole brain dose was 0.5 to 2 Gy. Neuropsychological testing included assessment of general intelligence (Wechsler Adult Intelligence Scale), attention (modified Trail-Making Test A, Digit Symbol Test, D2 Test, Wiener Determination Machine) and memory (Rey Auditory Verbal Learning Test, Benton Visual Retention Test). During follow-up, alternate test versions were used. Neuropsychological deficits were defined as a test score of at least one standard deviation (SD) below the mean of the normal distribution. Results: The pretherapeutic evaluation revealed marked deviations from the normal population; 24% had deficits in intelligence (range 23-31% in different subtests), attention (35%, 23-59%) and memory (48%, 31-61%). The overall percentage of aberrant results was reduced by 12% (memory) to 14% (attention) in the chronic phase up to 12 months after therapy. The improvement in test scores was significant (p < 0.05) in 3 of 4 subtests of attention functions. Conclusions: The acute tolerance of radiosurgery seems to be very good in these patients, showing no relevant increase in number of patients with neuropsychological deficits. Although the long-term follow-up needs to be further increased, our data indicate a tendency to slight improvement in the overall neuropsychological performance of AVM patients in the chronic phase after radiosurgery

Radiosurgery of pituitary adenomas

International Nuclear Information System (INIS)

Kida, Yoshihisa

2008-01-01

The efficacy and role of gamma knife (GK) in the treatment of various pituitary adenomas are described on author's experience and discussed with literature. GK subjects are 328 patients (M 126/F 202, av. age of 47.8 y) in author's hospital, and satisfactory follow-up (32-44 mo) for evaluation has been possible in 253 cases, who had tumors non-functional (129 cases), producing ACTH (23), HGH (70) and PRL (31). Stereotactic GK radiosurgery is done with navigation by Gamma Plan based on enhanced MRI images at various doses, and evaluation in the follow-up period is performed by hormonal levels and MRI which give efficacy of complete response (CR), partial response (PR), MR and standard deviation (SD)/ progressive disease (PD) on the tumor size. The overall tumor control rate is found to be 95-100%. Effectiveness (CR and PR) is found as high as 77.4% in PRL-producing tumor (marginal dose 14-32 Gy), 65% in non-functioning (15-25 Gy), 61% in ACTH (19-30 Gy) and 60% in GH (19-31 Gy), of which tendency is similar to that in literature. Even in ACTH-producing tumor, low ACTH and cortisol levels persisted with tendency of improved obese and hypertensive symptoms. GK radiosurgery has limitations in the tissue size and distance between the tumor and optic nerve/chiasm, but for the enough small tumor, it gives satisfactorily long term efficacy. (R.T.)

Do patients with a limited number of brain metastases need whole-brain radiotherapy in addition to radiosurgery?

International Nuclear Information System (INIS)

Rades, D.; Schild, S.E.

2012-01-01

Background: About 40% of patients with brain metastases have a very limited number of lesions and may be candidates for radiosurgery. Radiosurgery alone is superior to whole-brain radiotherapy (WBRT) alone for control of treated and new brain metastases. In patients with a good performance status, radiosurgery also resulted in better survival. However, the question is whether the results of radiosurgery alone can be further improved with additional WBRT. Methods: Information for this review was compiled by searching the PubMed and MEDLINE databases. Very important published meeting abstracts were also considered. Results: Based on both retrospective and prospective studies, the addition of WBRT to radiosurgery improved control of treated and new brain metastases but not survival. However, because a recurrence within the brain has a negative impact on neurocognitive function, it is important to achieve long-term control of brain metastases. Conclusion: The addition of WBRT provides significant benefits. Further randomized studies including adequate assessment of neurocognitive function and a follow-up period of at least 2 years are needed to help customize the treatment for individual patients. (orig.)

Pain relief by Cyberknife radiosurgery for spinal metastasis.

Science.gov (United States)

Lee, Sunyoung; Chun, Mison

2012-01-01

To report pain relief effect in patients with spinal metastases treated with Cyberknife® and to analyze the factors associated with pain relapse after initial pain relief. We retrospectively analyzed patients with spinal metastasis treated with stereotactic body radiosurgery between April 2007 and June 2009. A total of 57 patients with 73 lesions were available for analysis with a median follow-up of 6.8 months (range, 1-30). Pain was assessed by a verbal/visual analogue scale at each visit: from 0 to 10. Pain relief was defined as a decrease of at least three levels of the pain score without an increase in analgesic use. Complete relief was defined as no analgesics or a score 0 or 1. Pain relief was achieved in 88% of the lesions, with complete relief in 51% within 7 days from the start of radiosurgery. The median duration of pain relief was 3.2 months (range, 1-30). Pain reappeared in 16 patients (27%). Spinal cord compression (P = 0.001) and performance status (P = 0.01) were predictive of pain relapse by multivariate Cox analysis. All 6 patients treated with solitary spinal metastasis experienced pain relief; 5 of them were alive without evidence of disease at a median of 16 months (range, 7-30). As previous studies have shown, our study confirms that pain relief with spinal radiosurgery is around 90%. In particular, long-term pain relief and disease control was observed in patients with solitary spinal metastasis.

Linear accelerator radiosurgery for trigeminal neuralgia: case report

Energy Technology Data Exchange (ETDEWEB)

Yun, Hyong Geun [Dongguk University International Hospital, Goyang (Korea, Republic of)

2006-06-15

Trigeminal neuralgia is defined as an episodic electrical shock-like sensation in a dermatomal distribution of the trigeminal nerve. When medications fail to control pain, various procedures are used to attempt to control refractory pain. Of available procedures, stereotactic radiosurgery is the least invasive procedure and has been demonstrated to produce significant pain relief with minimal side effects. Recently, linear accelerators were introduced as a tool for radiosurgery of trigeminal neuralgia beneath the already accepted gamma unit. Author have experienced one case with trigeminal neuralgia treated with linear accelerator. The patient was treated with 85 Gy by means of 5 mm collimator directed to trigeminal nerve root entry zone. The patient obtained pain free without medication at 20 days after the procedure and remain pain free at 6 months after the procedure. He didn't experience facial numbness or other side effects.

Stereotactic radiosurgery for spinal metastases: a literature review; Radiocirurgia estereotaxica para metastases de coluna vertebral: revisao de literatura

Energy Technology Data Exchange (ETDEWEB)

Joaquim, Andrei Fernandes; Ghizoni, Enrico; Tedeschi, Helder; Pereira, Eduardo Baldon; Giacomini, Leonardo Abdala, E-mail: andjoaquim@yahoo.com [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil)

2013-04-15

Objective: The spine is the most common location for bone metastases. Since cure is not possible, local control and relief of symptoms is the basis for treatment, which is grounded on the use of conventional radiotherapy. Recently, spinal radiosurgery has been proposed for the local control of spinal metastases, whether as primary or salvage treatment. Consequently, we carried out a literature review in order to analyze the indications, efficacy, and safety of radiosurgery in the treatment of spinal metastases. Methods: We have reviewed the literature using the PubMed gateway with data from the Medline library on studies related to the use of radiosurgery in treatment of bone metastases in spine. The studies were reviewed by all the authors and classified as to level of evidence, using the criterion defined by Wright. Results: The indications found for radiosurgery were primary control of epidural metastases (evidence level II), myeloma (level III), and metastases known to be poor responders to conventional radiotherapy - melanoma and renal cell carcinoma (level III). Spinal radiosurgery was also proposed for salvage treatment after conventional radiotherapy (level II). There is also some evidence as to the safety and efficacy of radiosurgery in cases of extramedullar and intramedullar intradural metastatic tumors (level III) and after spinal decompression and stabilization surgery. Conclusion: Radiosurgery can be used in primary or salvage treatment of spinal metastases, improving local disease control and patient symptoms. It should also be considered as initial treatment for radioresistant tumors, such as melanoma and renal cell carcinoma. (author)

Surgery for acoustic neurinoma treated by gamma-knife radiosurgery. A case report

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Tokuda, Kentaro; Inamura, Takanori; Uesaka, Toshio; Matsushima, Toshio; Fukui, Masashi [Kyushu Univ., Fukuoka (Japan). Graduate School of Medical Science; Kenai, Hiroyuki; Karashima, Atushi

2001-08-01

A 52-year-old woman had a history of left hearing loss for 5 years. An acoustic neurinoma with 3.2 cm in diameter was diagnosed and treated with gamma-knife radiosurgery (19 Gy of marginal dose) 1 year and 4 months ago. She developed headache, nausea, and visual disturbance 1 month prior to admission. Slight left facial palsy appeared after radiosurgery. Magnetic resonance imaging demonstrated the tumor with central necrosis in the left cerebellopontine angle cistern, increasing in size to 3.5 cm in diameter, and hydrocephalus. Tumor removal was performed incompletely, because of the fibrous appearance of the tumor and severe adherence with the surrounding cerebellar tissue. Facial palsy did not worsen after surgery. Since the hydrocephalus was not resolved, a right ventriculo-peritoneal shunt was inserted. The clinical course in this case suggests that tumor removal followed by radiosurgery was an approximately effective treatment for large acoustic neurinoma. (author)

Gamma Knife radiosurgery for the treatment of intracranial dural arteriovenous fistulas

Science.gov (United States)

Dmytriw, Adam A; Schwartz, Michael L; Cusimano, Michael D; Mendes Pereira, Vitor; Krings, Timo; Tymianski, Michael; Radovanovic, Ivan

2016-01-01

Background Intracranial dural arteriovenous fistulae (DAVF) may present a treatment challenge. Endovascular embolization is in most cases the first line of treatment but does not always achieve cure. Gamma Knife (GK) radiosurgery represents an alternative treatment option, and the purpose of this study was to further evaluate its utility. Methods We reviewed all cases of DAVF treated between 2009 and 2016 at our institution with GK radiosurgery independently, or following failed/refused endovascular or surgical management. Patients’ clinical files, radiological images, catheter angiograms, and surgical DAVF disconnection reports were retrospectively reviewed. Results Sixteen DAVF (14 patients) treated by GK radiosurgery were identified. Eleven fistulae were aggressive and five were benign. Marginal doses ranged from 15 to 25 Gy. Target volumes ranged from 0.04 to 4.47 cm3. In all symptomatic patients, GK treatment resulted in symptom palliation. In 13/15 lesions, cure of symptoms (86.0%) was reported. One lesion was asymptomatic. Angiographic cure was achieved in eight cases (50%), small residual DAVF occurred in four, and four were unchanged. One patient developed headache that resolved at one year. No hemorrhage occurred during the follow-up period. There was no significant association between Borden type and cure rate. Prior failed endovascular treatment and small target volume were associated with lower rates of cure. Conclusions Stereotactic radiosurgery is viable treatment for DAVF. It is very effective in palliating symptoms as a de novo approach or adjunctive to endovascular therapy. In our experience it is only somewhat effective in achieving complete angiographic cure. PMID:28156167

Therapeutic cranial nerve irradiation: results from a multi-center dose response study of radiosurgery for trigeminal neuralgia

Energy Technology Data Exchange (ETDEWEB)

Kondziolka, D; Flickinger, J; Lunsford, L D; Young, R; Vermeulen, S; Duma, C; Jacques, D B; Rand, R; Regis, J; Peragut, J C; Epstein, M H; Lindquist, C

1995-07-01

Purpose/Objective: We performed a multi-institution study to evaluate the technique, dose-selection parameters, and results of gamma knife stereotactic radiosurgery in the management of trigeminal neuralgia. We hypothesized that MRI-stereotactic targeting of the trigeminal nerve and irradiation with a single 4 mm isocenter, 2-4 mm anterior to the brainstem, could be a safe and effective treatment for this disorder. Materials and Methods: Fifty patients at five centers had radiosurgery using a single 4 mm isocenter targeted at the root entry zone. All patients had typical trigeminal neuralgia. The mean patient age was 70 years, (range, 40-87). Thirty-two patients had undergone prior surgery, and the mean number of procedures performed was 2.8 (range, 1-7). Eighteen patients (36%) had not had prior surgery before radiosurgery. Maximum radiosurgery doses included 60 Gy (n=8), 65 Gy (n=3), 70 Gy (n=27), 75 Gy (n=2), 80 Gy (n=6) and 90 Gy (n=4). All patients were discharged within 24 hours and were studied in regard to the degree of pain relief, latency interval to pain relief, sensory loss, and the need for further therapy. Mean follow-up after radiosurgery was 9.2 months (range, 2-26 months). Results: At last follow-up, 25 patients (50%) had excellent control (pain-free), 17 (34%) had good control (50-90% relief), and 8 (16%) had failed (see Figure). The median time to pain relief was one month. We identified an actuarial response rate of 53% for complete pain relief at seven months, and 93% for pain reduction (50-100% relief). At 18 months, these results declined to 48% and 77% respectively. A significantly greater proportion of patients receiving a radiosurgery maximum dose of {>=} 70 Gy achieved complete pain relief (63% vs. 18%) and >50% pain reduction (96% vs. 80%) than those with doses <70 Gy. Patients without prior surgery had significantly better outcomes in univariate testing. Three patients (6%) developed increased facial paresthesiae after radiosurgery

Therapeutic cranial nerve irradiation: results from a multi-center dose response study of radiosurgery for trigeminal neuralgia

International Nuclear Information System (INIS)

Kondziolka, D.; Flickinger, J.; Lunsford, L.D.; Young, R.; Vermeulen, S.; Duma, C.; Jacques, D.B.; Rand, R.; Regis, J.; Peragut, J.C.; Epstein, M.H.; Lindquist, C.

1995-01-01

Purpose/Objective: We performed a multi-institution study to evaluate the technique, dose-selection parameters, and results of gamma knife stereotactic radiosurgery in the management of trigeminal neuralgia. We hypothesized that MRI-stereotactic targeting of the trigeminal nerve and irradiation with a single 4 mm isocenter, 2-4 mm anterior to the brainstem, could be a safe and effective treatment for this disorder. Materials and Methods: Fifty patients at five centers had radiosurgery using a single 4 mm isocenter targeted at the root entry zone. All patients had typical trigeminal neuralgia. The mean patient age was 70 years, (range, 40-87). Thirty-two patients had undergone prior surgery, and the mean number of procedures performed was 2.8 (range, 1-7). Eighteen patients (36%) had not had prior surgery before radiosurgery. Maximum radiosurgery doses included 60 Gy (n=8), 65 Gy (n=3), 70 Gy (n=27), 75 Gy (n=2), 80 Gy (n=6) and 90 Gy (n=4). All patients were discharged within 24 hours and were studied in regard to the degree of pain relief, latency interval to pain relief, sensory loss, and the need for further therapy. Mean follow-up after radiosurgery was 9.2 months (range, 2-26 months). Results: At last follow-up, 25 patients (50%) had excellent control (pain-free), 17 (34%) had good control (50-90% relief), and 8 (16%) had failed (see Figure). The median time to pain relief was one month. We identified an actuarial response rate of 53% for complete pain relief at seven months, and 93% for pain reduction (50-100% relief). At 18 months, these results declined to 48% and 77% respectively. A significantly greater proportion of patients receiving a radiosurgery maximum dose of ≥ 70 Gy achieved complete pain relief (63% vs. 18%) and >50% pain reduction (96% vs. 80%) than those with doses <70 Gy. Patients without prior surgery had significantly better outcomes in univariate testing. Three patients (6%) developed increased facial paresthesiae after radiosurgery

Vagus nerve stimulation and stereotactic radiosurgery

International Nuclear Information System (INIS)

Kawai, Kensuke

2005-01-01

Vagus nerve stimulation and stereotactic radiosurgery represent novel and less invasive therapeutics for medically intractable epilepsy. Chronic stimulation of the left vagus nerve with implanted generator and electrodes inhibits seizure susceptibility of the cerebral cortices. While the underlying mechanisms of the effect remains to be further elucidated, the efficacy and safety of vagus nerve stimulation have been established by randomized clinical trials in the United States and European countries. It has been widely accepted as a treatment option for patients with medically intractable epilepsy and for whom brain surgery is not indicated. The primary indication of vagus nerve stimulation in the clinical trials was localization-related epilepsy in adult patients but efficacy in a wide range of patient groups such as generalized epilepsy and children has been reported. Improvements in daytime alertness, mood, higher cognitive functions and overall quality of life have been reported other than the effect on epileptic seizures. Since the devices are not approved for clinical use in Japan by the Health, Labor and Welfare Ministry, there exist barriers to provide this treatment to patients at present. Stereotactic radiosurgery has been used for temporal lobe epilepsy and hypothalamic hamartoma, but it is still controversial whether the therapy is more effective and less invasive than brain surgery. Promising results of gamma knife radiosurgery for medically intractable temporal lobe epilepsy with unilateral hippocampal sclerosis have been reported essentially from one French center. Results from others were not as favorable. There seems to be an unignorable risk of brain edema and radiation necrosis when the delivered dose over the medial temporal structures is high enough to abolish epileptic seizures. A randomized clinical trial comparing different marginal doses is ongoing in the United States. Clinical trials like this, technical advancement and standardization

Intra-arterial angio-CT for radiosurgery of cerebral arteriovenous malformations

International Nuclear Information System (INIS)

Tanami, Yutaka; Kunieda, Etsuo; Onozuka, Satoshi

1998-01-01

Intra-arterial CT-angiograms were performed for four patients undergoing stereotactic radiosurgery for cerebral arteriovenous malformations (AVM). Helical and dynamic CT scans were carried out with a scanner installed in a angiographic examination room following routine angiography. Helical scans were performed with continuous arterial infusion of contrast media. Then, dynamic scans were repeated at several table positions. Subtractions were achieved for a post-embolization case. Normal and pathological vascular structures were demonstrated with different enhancement phases with the dynamic scans. The coordinates of the target points in the nidus could be clearly determined. We concluded that intra-arterial CT-angiograms are practical and useful for treatment planning of radiosurgery for cerebral AVM. (author)

Intra-arterial angio-CT for radiosurgery of cerebral arteriovenous malformations

Energy Technology Data Exchange (ETDEWEB)

Tanami, Yutaka; Kunieda, Etsuo; Onozuka, Satoshi [Keio Univ., Tokyo (Japan) School of Medicine] [and others

1998-08-01

Intra-arterial CT-angiograms were performed for four patients undergoing stereotactic radiosurgery for cerebral arteriovenous malformations (AVM). Helical and dynamic CT scans were carried out with a scanner installed in a angiographic examination room following routine angiography. Helical scans were performed with continuous arterial infusion of contrast media. Then, dynamic scans were repeated at several table positions. Subtractions were achieved for a post-embolization case. Normal and pathological vascular structures were demonstrated with different enhancement phases with the dynamic scans. The coordinates of the target points in the nidus could be clearly determined. We concluded that intra-arterial CT-angiograms are practical and useful for treatment planning of radiosurgery for cerebral AVM. (author)

Image-guided robotic radiosurgery for spinal metastases

International Nuclear Information System (INIS)

Gibbs, Iris C.; Kamnerdsupaphon, Pimkhuan; Ryu, Mi-Ryeong; Dodd, Robert; Kiernan, Michaela; Chang, Steven D.; Adler, John R.

2007-01-01

Background and Purpose: To determine the effectiveness and safety of image-guided robotic radiosurgery for spinal metastases. Materials/Methods: From 1996 to 2005, 74 patients with 102 spinal metastases were treated using the CyberKnife TM at Stanford University. Sixty-two (84%) patients were symptomatic. Seventy-four percent (50/68) of previously treated patients had prior radiation. Using the CyberKnife TM , 16-25 Gy in 1-5 fractions was delivered. Patients were followed clinically and radiographically for at least 3 months or until death. Results: With mean follow-up of 9 months (range 0-33 months), 36 patients were alive and 38 were dead at last follow-up. No death was treatment related. Eighty-four (84%) percent of symptomatic patients experienced improvement or resolution of symptoms after treatment. Three patients developed treatment-related spinal injury. Analysis of dose-volume parameters and clinical parameters failed to identify predictors of spinal cord injury. Conclusions: Robotic radiosurgery is effective and generally safe for spinal metastases even in previously irradiated patients

Calculation of cranial nerve complication probability for acoustic neuroma radiosurgery

International Nuclear Information System (INIS)

Meeks, Sanford L.; Buatti, John M.; Foote, Kelly D.; Friedman, William A.; Bova, Francis J.

2000-01-01

Purpose: Estimations of complications from stereotactic radiosurgery usually rely simply on dose-volume or dose-diameter isoeffect curves. Due to the sparse clinical data available, these curves have typically not considered the target location in the brain, target histology, or treatment plan conformality as parameters in the calculation. In this study, a predictive model was generated to estimate the probability of cranial neuropathies as a result of acoustic schwannoma radiosurgery. Methods and Materials: The dose-volume histogram reduction scheme was used to calculate the normal tissue complication probability (NTCP) from brainstem dose-volume histograms. The model's fitting parameters were optimized to provide the best fit to the observed complication data for acoustic neuroma patients treated with stereotactic radiosurgery at the University of Florida. The calculation was then applied to the remainder of the patients in the database. Results: The best fit to our clinical data was obtained using n = 0.04, m = 0.15, and no. alphano. /no. betano. = 2.1 Gy -1 . Although the fitting parameter m is relatively consistent with ranges found in the literature, both the volume parameter, n, and no. alphano. /no. betano. are much smaller than the values quoted in the literature. The fit to our clinical data indicates that brainstem, or possibly a specific portion of the brainstem, is more radiosensitive than the parameters in the literature indicate, and that there is very little volume effect; in other words, irradiation of a small fraction of the brainstem yields NTCPs that are nearly as high as those calculated for entire volume irradiation. These new fitting parameters are specific to acoustic neuroma radiosurgery, and the small volume effect that we observe may be an artifact of the fixed relationship of acoustic tumors to specific regions of the brainstem. Applying the model to our patient database, we calculate an average NTCP of 7.2% for patients who had no

Biophysical characterization of a relativistic proton beam for image-guided radiosurgery.

Science.gov (United States)

Yu, Zhan; Vanstalle, Marie; La Tessa, Chiara; Jiang, Guo-Liang; Durante, Marco

2012-07-01

We measured the physical and radiobiological characteristics of 1 GeV protons for possible applications in stereotactic radiosurgery (image-guided plateau-proton radiosurgery). A proton beam was accelerated at 1 GeV at the Brookhaven National Laboratory (Upton, NY) and a target in polymethyl methacrylate (PMMA) was used. Clonogenic survival was measured after exposures to 1-10 Gy in three mammalian cell lines. Measurements and simulations demonstrate that the lateral scattering of the beam is very small. The lateral dose profile was measured with or without the 20-cm plastic target, showing no significant differences up to 2 cm from the axis A large number of secondary swift protons are produced in the target and this leads to an increase of approximately 40% in the measured dose on the beam axis at 20 cm depth. The relative biological effectiveness at 10% survival level ranged between 1.0 and 1.2 on the beam axis, and was slightly higher off-axis. The very low lateral scattering of relativistic protons and the possibility of using online proton radiography during the treatment make them attractive for image-guided plateau (non-Bragg peak) stereotactic radiosurgery.

Biophysical characterization of a relativistic proton beam for image-guided radiosurgery

International Nuclear Information System (INIS)

Yu, Z.; Vanstalle, M.; La Tessa, C.; Durante, M.; Jiang Guoliang

2012-01-01

We measured the physical and radiobiological characteristics of 1 GeV protons for possible applications in stereotactic radiosurgery (image-guided plateau-proton radiosurgery). A proton beam was accelerated at 1 GeV at the Brookhaven National Laboratory (Upton, NY) and a target in polymethyl methacrylate (PMMA) was used. Clonogenic survival was measured after exposures to 1-10 Gy in three mammalian cell lines. Measurements and simulations demonstrate that the lateral scattering of the beam is very small. The lateral dose profile was measured with or without the 20-cm plastic target, showing no significant differences up to 2 cm from the axis A large number of secondary swift protons are produced in the target and this leads to an increase of approximately 40% in the measured dose on the beam axis at 20 cm depth. The relative biological effectiveness at 10% survival level ranged between 1.0 and 1.2 on the beam axis, and was slightly higher off-axis. The very low lateral scattering of relativistic protons and the possibility of using online proton radiography during the treatment make them attractive for image-guided plateau (non-Bragg peak) stereotactic radiosurgery. (author)

Radiation tolerance of normal temporal bone structures: implications for gamma knife stereotactic radiosurgery

International Nuclear Information System (INIS)

Linskey, Mark E.; Johnstone, Peter A.

2003-01-01

Popular current thought states that hearing loss and facial weakness after radiosurgery of vestibular schwannomas is a function of cranial nerve damage. Although this may be true in some cases, the middle and inner ear contain rich networks of other sensitive structures that are at risk after radiotherapy and that may contribute to toxicity afterward. We reviewed the limited reported data regarding radiation tolerance of external, middle, and inner ear structures, and perspectives for therapy with gamma knife stereotactic radiosurgery are addressed

Intracranial radiosurgery in the Netherlands. A planning comparison of available systems with regard to physical aspects and workload.

NARCIS (Netherlands)

Schoonbeek, A.; Monshouwer, R.; Hanssens, P.; Raaijmakers, E.; Nowak, P.; Marijnissen, J.P.; Lagerwaard, F.J.; Cuijpers, J.P.; Vonk, E.J.; Maazen, R.W.M. van der

2010-01-01

Different planning and treatment systems for intracranial stereotactic radiosurgery available in the Netherlands are compared. The systems for intracranial radiosurgery include: Gamma Knife, Cyberknife, Novalis, and Tomotherapy. Electronic data of 5 patients was transferred to all participating

Dose and diameter relationships for facial, trigeminal, and acoustic neuropathies following acoustic neuroma radiosurgery

International Nuclear Information System (INIS)

Flickinger, John C.; Kondziolka, Douglas; Lunsford, L. Dade

1996-01-01

Purpose and objective: To define the relationships between dose and tumor diameter for the risks of developing trigeminal, facial, and acoustic neuropathies after acoustic neuroma radiosurgery, a large single-institution experience was analyzed. Materials and methods: Two hundred and thirty-eight patients with unilateral acoustic neuromas who underwent Gamma knife radiosurgery between 1987-1994 with 6-91 months of follow-up (median 30 months) were studied. Minimum tumor doses were 12-20 Gy (median 15 Gy). Transverse tumor diameter varied from 0.3-5.5 cm (median 2.1 cm). The relationships of dose and diameter to the development of cranial neuropathies were delineated by multivariate logistic regression. Results: The development of post-radiosurgery neuropathies affecting cranial nerves V, VII, and VIII were correlated with minimum tumor dose and transverse tumor diameter (P min for VIII where P=0.10). A comparison of the dose-diameter response curves showed the acoustic nerve to be the most sensitive to doses of 12-16 Gy and the facial nerve to be the least sensitive. Conclusion: The risks of developing trigeminal, facial, and acoustic neuropathies following acoustic neuroma radiosurgery can be predicted from the transverse tumor diameter and the minimum tumor dose using models constructed from data presently available

Radiosurgery with the gamma knife; Radiochirurgie mit dem Gamma-Knife

Energy Technology Data Exchange (ETDEWEB)

Wowra, B.; Reulen, H.J.

1996-05-10

Radiosurgery is a novel modality introduced by the neurosurgeon Lars Leksell. For the most important lesions, (arteriovenous angiomas, benign tumors in the base of the skull, formation of metastases in the brain), radiosurgery is a valuable additional tool in the range of therapies available to the benefit of patients. The gamma knife has been gaining a leading rank in the range of therapies applied in Germany. (orig.) [Deutsch] Radiochirurgie ist ein neues, von dem Neurochirurgen Lars Leksell konzipiertes Prinzip. Bei den wichtigsten Indikationen (arteriovenoese Angiome, gutartige Tumoren der Schaedelbasis, Hirnmetastasen etc.) bereichert und ergaenzt die Radiochirurgie das therapeutische Arsenal der Neurochirurgie zum Vorteil der Patienten betraechtlich. Dem Gamma-Knife kommt jetzt auch in Deutschland ein prominenter Platz unter den verschiedenen radiochirurgischen Verfahren zu. (orig.)

Optic neuritis in a case after gamma knife radiosurgery for relapsed pituitary adenoma

International Nuclear Information System (INIS)

Hosoda, Atsuhide; Mizunoya, Satoshi; Abe, Hideki; Kanai, Hidehito; Ikeda, Kazutoshi; Kidahashi, Hisaharu; Suzuki, Masanobu

2008-01-01

The purpose of this study was to report a case of optic neuritis after gamma knife radiosurgery for pituitary adenoma. A 41-year-old woman presented with impaired vision in both eyes since 5 days before. She had received surgery for pituitary tumor 5 years before. She was treated by gamma knife radiosurgery for relapse of tumor 50 days before. Her corrected visual acuity was 0.5 right and 0.6 left. She had abnormal color sense. Flicker fusion frequency was decreased in both eyes. Both eyes showed enlarged blind spot and relative scotoma in the superior sector. Magnetic resonance imaging (MRI) showed enhanced signal in the optic nerve sheath. These findings led to the diagnosis of optic neuritis. Pulsed corticosteroid therapy was followed by improved vision of 1.2 in either eye. She has been doing well for 18 months until present. This case illustrates that optic neuritis may develop after gamma knife radiosurgery. (author)

Cognitive function in patients with cerebral arteriovenous malformations after radiosurgery: prospective long-term follow-up

International Nuclear Information System (INIS)

Steinvorth, Sarah; Wenz, Frederik; Wildermuth, Susanne; Essig, Marco; Fuss, Martin; Lohr, Frank; Debus, Juergen; Wannenmacher, Michael; Hacke, Werner

2002-01-01

Purpose: To evaluate the long-term cognitive function of patients with cerebral arteriovenous malformations (AVMs) after radiosurgery. Methods and Materials: The data of 95 AVM patients were prospectively assessed up to 3 years after radiosurgery. Of these patients, 39 had a follow-up of at least 2 years. Radiosurgery was performed using a modified linear accelerator (minimal doses to the target volume 15-22 Gy, median dose 20). The neuropsychological evaluation included testing of intelligence, attention, and memory. The effect of a preexisting intracranial hemorrhage, as well as AVM occlusion, on cognitive functions was analyzed after 1 and 2 years. Results: No cognitive declines were observed during follow-up. Instead significant improvements occurred in intelligence (1 year, +6.1 IQ points; 2 years, +5.1 IQ points), memory (1 year, +18.3 percentile score; 2 years, +12.2 percentile score), and attention (1 year, +19 percentile score; 2 years, +18 percentile score). Patients without previous intracranial hemorrhage improved more than patients with intracranial hemorrhage, although this difference was not statistically significant. The role of AVM occlusion on cognitive function is not clear at present. Conclusion: Radiosurgery does not induce measurable deterioration of cognitive function in patients with cerebral AVMs

Gamma knife radiosurgery for arteriovenous malformation in children

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Takayuki; Kobayashi, Tatsuya [Komaki City Hospital, Aichi (Japan)

1995-04-01

Intracranial arteriovenous malformations (AVM) of 38 children were treated by gamma knife radiosurgery. Their clinical courses and the effect of the treatment in 19 patients who had angiographies are described. There were 21 boys and 17 girls with a mean age of 11.2 years. The initial signs and symptoms were: intracranial hemorrhage in 32, seizures in 4, and headache in 2. Prior to the radiosurgery, craniotomy was performed in 10 patients, ventricular drainage, in 8, ventriculoperitoneal shunting in 4, and intravascular embolization in 3. The AVM was in the parietal lobe in 8 patients, in the thalamus in 7, in the occipital lobe in 5, in the temporal lobe in 4, in the basal ganglia in 4, in the corpus callosum in 3, and in other locations in 8. The mean diameter of the nidus was 18.9 mm. According to Spetzler`s classification of AVM, 23 (60.5%) were grade III, 10 were grade II, 3 were grade IV, and 2 were grade VI. The mean maximum dose was 36.3 Gy, and the mean peripheral dose was 20.2 Gy. Follow-up angiography was done in 19 patients during a mean follow-up period of 14.9 months. Complete occlusion of the nidus was obtained within 1 year in 10 of 15 patients (67%). All 6 patients who underwent angiography 2 years after treatment showed complete obliteration of the AVM. Only 1 patient developed hemiparesis due to radiation necrosis. It is considered that occlusion of AVMs by gamma knife radiosurgery is probably more effective and safer in children than in adults. (author).

Stereotactic radiosurgery versus stereotactic radiotherapy for patients with vestibular schwannoma: a Leksell Gamma Knife Society 2000 debate.

Science.gov (United States)

Linskey, Mark E

2013-12-01

By definition, the term "radiosurgery" refers to the delivery of a therapeutic radiation dose in a single fraction, not simply the use of stereotaxy. Multiple-fraction delivery is better termed "stereotactic radiotherapy." There are compelling radiobiological principles supporting the biological superiority of single-fraction radiation for achieving an optimal therapeutic response for the slowly proliferating, late-responding, tissue of a schwannoma. It is axiomatic that complication avoidance requires precise three-dimensional conformality between treatment and tumor volumes. This degree of conformality can only be achieved through complex multiisocenter planning. Alternative radiosurgery devices are generally limited to delivering one to four isocenters in a single treatment session. Although they can reproduce dose plans similar in conformality to early gamma knife dose plans by using a similar number of isocenters, they cannot reproduce the conformality of modern gamma knife plans based on magnetic resonance image--targeted localization and five to 30 isocenters. A disturbing trend is developing in which institutions without nongamma knife radiosurgery (GKS) centers are championing and/or shifting to hypofractionated stereotactic radiotherapy for vestibular schwannomas. This trend appears to be driven by a desire to reduce complication rates to compete with modern GKS results by using complex multiisocenter planning. Aggressive advertising and marketing from some of these centers even paradoxically suggests biological superiority of hypofractionation approaches over single-dose radiosurgery for vestibular schwannomas. At the same time these centers continue to use the term radiosurgery to describe their hypofractionated radiotherapy approach in an apparent effort to benefit from a GKS "halo effect." It must be reemphasized that as neurosurgeons our primary duty is to achieve permanent tumor control for our patients and not to eliminate complications at the

Stereotactic radiosurgery XX: ocular neuromyotonia in association with gamma knife radiosurgery

Science.gov (United States)

McQuillan, Joe; Plowman, P Nicholas; MacDougall, Niall; Blackburn, Philip; Sabin, H Ian; Ali, Nadeem; Drake, William M

2015-01-01

Summary We report three patients who developed symptoms and signs of ocular neuromyotonia (ONM) 3–6 months after receiving gamma knife radiosurgery (GKS) for functioning pituitary tumours. All three patients were complex, requiring multi-modality therapy and all had received prior external irradiation to the sellar region. Although direct causality cannot be attributed, the timing of the development of the symptoms would suggest that the GKS played a contributory role in the development of this rare problem, which we suggest clinicians should be aware of as a potential complication. Learning points GKS can cause ONM, presenting as intermittent diplopia.ONM can occur quite rapidly after treatment with GKS.Treatment with carbamazepine is effective and improve patient's quality of life. PMID:26294961

Do patients with very few brain metastases from breast cancer benefit from whole-brain radiotherapy in addition to radiosurgery?

International Nuclear Information System (INIS)

Rades, Dirk; Huttenlocher, Stefan; Hornung, Dagmar; Blanck, Oliver; Schild, Steven E; Fischer, Dorothea

2014-01-01

An important issue in palliative radiation oncology is the whether whole-brain radiotherapy should be added to radiosurgery when treating a limited number of brain metastases. To optimize personalized treatment of cancer patients with brain metastases, the value of whole-brain radiotherapy should be described separately for each tumor entity. This study investigated the role of whole-brain radiotherapy added to radiosurgery in breast cancer patients. Fifty-eight patients with 1–3 brain metastases from breast cancer were included in this retrospective study. Of these patients, 30 were treated with radiosurgery alone and 28 with radiosurgery plus whole-brain radiotherapy. Both groups were compared for local control of the irradiated metastases, freedom from new brain metastases and survival. Furthermore, eight additional factors were analyzed including dose of radiosurgery, age at radiotherapy, Eastern Cooperative Oncology Group (ECOG) performance score, number of brain metastases, maximum diameter of all brain metastases, site of brain metastases, extra-cranial metastases and the time from breast cancer diagnosis to radiotherapy. The treatment regimen had no significant impact on local control in the univariate analysis (p = 0.59). Age ≤59 years showed a trend towards improved local control on univariate (p = 0.066) and multivariate analysis (p = 0.07). On univariate analysis, radiosurgery plus whole-brain radiotherapy (p = 0.040) and ECOG 0–1 (p = 0.012) showed positive associations with freedom from new brain metastases. Both treatment regimen (p = 0.039) and performance status (p = 0.028) maintained significance on multivariate analysis. ECOG 0–1 was positively correlated with survival on univariate analysis (p < 0.001); age ≤59 years showed a strong trend (p = 0.054). On multivariate analysis, performance status (p < 0.001) and age (p = 0.041) were significant. In breast cancer patients with few brain metastases, radiosurgery plus whole

Early versus late Gamma Knife radiosurgery following transsphenoidal surgery for nonfunctioning pituitary macroadenomas: a multicenter matched-cohort study.

Science.gov (United States)

Pomeraniec, I Jonathan; Kano, Hideyuki; Xu, Zhiyuan; Nguyen, Brandon; Siddiqui, Zaid A; Silva, Danilo; Sharma, Mayur; Radwan, Hesham; Cohen, Jonathan A; Dallapiazza, Robert F; Iorio-Morin, Christian; Wolf, Amparo; Jane, John A; Grills, Inga S; Mathieu, David; Kondziolka, Douglas; Lee, Cheng-Chia; Wu, Chih-Chun; Cifarelli, Christopher P; Chytka, Tomas; Barnett, Gene H; Lunsford, L Dade; Sheehan, Jason P

2017-10-27

OBJECTIVE Gamma Knife radiosurgery (GKRS) is frequently used to treat residual or recurrent nonfunctioning pituitary macroadenomas. There is no consensus as to whether GKRS should be used early after surgery or if radiosurgery should be withheld until there is evidence of imaging-defined progression of tumor. Given the high incidence of adenoma progression after subtotal resection over time, the present study intended to evaluate the effect of timing of radiosurgery on outcome. METHODS This is a multicenter retrospective review of patients with nonfunctioning pituitary macroadenomas who underwent transsphenoidal surgery followed by GKRS from 1987 to 2015 at 9 institutions affiliated with the International Gamma Knife Research Foundation. Patients were matched by adenoma and radiosurgical parameters and stratified based on the interval between last resection and radiosurgery. Operative results, imaging data, and clinical outcomes were compared across groups following early (≤ 6 months after resection) or late (> 6 months after resection) radiosurgery. RESULTS After matching, 222 patients met the authors' study criteria (from an initial collection of 496 patients) and were grouped based on early (n = 111) or late (n = 111) GKRS following transsphenoidal surgery. There was a greater risk of tumor progression after GKRS (p = 0.013) and residual tumor (p = 0.038) in the late radiosurgical group over a median imaging follow-up period of 68.5 months. No significant difference in the occurrence of post-GKRS endocrinopathy was observed (p = 0.68). Thirty percent of patients without endocrinopathy in the early cohort developed new endocrinopathies during the follow-up period versus 27% in the late cohort (p = 0.84). Fourteen percent of the patients in the early group and 25% of the patients in the late group experienced the resolution of endocrine dysfunction after original presentation (p = 0.32). CONCLUSIONS In this study, early GKRS was associated with a lower risk of

The results of gamma knife radiosurgery for malignant skull base tumors

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Takayuki; Kobayashi, Tatsuya; Kida, Yoshihisa; Oyama, Hirofumi; Niwa, Masahiro [Komaki City Hospital, Aichi (Japan)

1996-03-01

The results of gamma knife radiosurgery for malignant skull base tumors were analyzed using repeated magnetic resonance imagings and neurological examinations. Nineteen malignant skull base tumors were treated and followed up for 22.3 months (5-40 months) using MR imagings. The mean age was 54.4 years old (ranging from 16-85). Ten were male and 9 were female. Prior to the radiosurgery, removal of the tumors in 17 cases, conventional radiation therapy in 7, and chemotherapy in 4 etc. were performed. The pathological diagnoses were chordoma in 6 patients, metastatic tumors in 5, epipharyngeal carcinoma in 2, adenoid cystic carcinoma in 2, and others in 4. The locations of tumors were clivus in 8, parasellar region in 5, epipharynx in 2, paranasal sinus in 2, C-P angle in 1, and intraorbital region in 1 (14 intracranial and 5 extracranial). The mean diameter of the tumor was 33.5 mm. The mean maximum dose was 26.8 Gy and the mean marginal dose was 12.9 Gy during treatment. Repeated MR imagings revealed decrease of tumor size in 12 cases, showing no change in 1, and increase of tumor size in 5 (unknown in 1). Follow-up neurological examinations showed improvement in 3 patients, no change in 9, and deterioration in 7. There were 11 deaths during a mean follow-up period of 17.8 months (5-32 months) and another 8 cases are alive for a mean follow-up of 30.5 months (20-40 months) after the radiosurgery. Although the tumor size was large at the time of treatment, the results of gamma knife radiosurgery were promising. Considering the quality of life of patients with malignant skull base tumors, it is emphasized that gamma knife treatment is the method of choice compared with radical removal of the tumors. (author).

[Possibility of 3D Printing in Ophthalmology - First Experiences by Stereotactic Radiosurgery Planning Scheme of Intraocular Tumor].

Science.gov (United States)

Furdová, A; Furdová, Ad; Thurzo, A; Šramka, M; Chorvát, M; Králik, G

Nowadays 3D printing allows us to create physical objects on the basis of digital data. Thanks to its rapid development the use enormously increased in medicine too. Its creations facilitate surgical planning processes, education and research in context of organ transplantation, individualization prostheses, breast forms, and others.Our article describes the wide range of applied 3D printing technology possibilities in ophthalmology. It is focusing on innovative implementation of eye tumors treatment planning in stereotactic radiosurgery irradiation.We analyze our first experience with 3D printing model of the eye in intraocular tumor planning stereotactic radiosurgery. 3D printing, model, Fused Deposition Modelling, stereotactic radiosurgery, prostheses, intraocular tumor.

Linear Accelerator-Based Radiosurgery Alone for Arteriovenous Malformation: More Than 12 Years of Observation

Energy Technology Data Exchange (ETDEWEB)

Matsuo, Takayuki, E-mail: takayuki@nagasaki-u.ac.jp; Kamada, Kensaku; Izumo, Tsuyoshi; Hayashi, Nobuyuki; Nagata, Izumi

2014-07-01

Purpose: Although radiosurgery is an accepted treatment method for intracranial arteriovenous malformations (AVMs), its long-term therapeutic effects have not been sufficiently evaluated, and many reports of long-term observations are from gamma-knife facilities. Furthermore, there are few reported results of treatment using only linear accelerator (LINAC)-based radiosurgery (LBRS). Methods and Materials: Over a period of more than 12 years, we followed the long-term results of LBRS treatment performed in 51 AVM patients. Results: The actuarial obliteration rates, after a single radiosurgery session, at 3, 5, 10, and 15 years were 46.9%, 54.0%, 64.4%, and 68.0%, respectively; when subsequent radiosurgeries were included, the rates were 46.9%, 61.3%, 74.2%, and 90.3%, respectively. Obliteration rates were significantly related to target volumes ≥4 cm{sup 3}, marginal doses ≥12 Gy, Spetzler-Martin grades (1 vs other), and AVM scores ≥1.5; multivariate analyses revealed a significant difference for target volumes ≥4 cm{sup 3}. The postprocedural actuarial symptomatic radiation injury rates, after a single radiation surgery session, at 5, 10, and 15 years were 12.3%, 16.8%, and 19.1%, respectively. Volumes ≥4 cm{sup 3}, location (lobular or other), AVM scores ≥1.5, and the number of radiosurgery were related to radiation injury incidence; multivariate analyses revealed significant differences associated with volumes ≥4 cm{sup 3} and location (lobular or other). Conclusions: Positive results can be obtained with LBRS when performed with a target volume ≤4 cm{sup 3}, an AVM score ≤1.5, and ≥12 Gy radiation. Bleeding and radiation injuries may appear even 10 years after treatment, necessitating long-term observation.

Cone beam computed tomography image guidance system for a dedicated intracranial radiosurgery treatment unit.

Science.gov (United States)

Ruschin, Mark; Komljenovic, Philip T; Ansell, Steve; Ménard, Cynthia; Bootsma, Gregory; Cho, Young-Bin; Chung, Caroline; Jaffray, David

2013-01-01

Image guidance has improved the precision of fractionated radiation treatment delivery on linear accelerators. Precise radiation delivery is particularly critical when high doses are delivered to complex shapes with steep dose gradients near critical structures, as is the case for intracranial radiosurgery. To reduce potential geometric uncertainties, a cone beam computed tomography (CT) image guidance system was developed in-house to generate high-resolution images of the head at the time of treatment, using a dedicated radiosurgery unit. The performance and initial clinical use of this imaging system are described. A kilovoltage cone beam CT system was integrated with a Leksell Gamma Knife Perfexion radiosurgery unit. The X-ray tube and flat-panel detector are mounted on a translational arm, which is parked above the treatment unit when not in use. Upon descent, a rotational axis provides 210° of rotation for cone beam CT scans. Mechanical integrity of the system was evaluated over a 6-month period. Subsequent clinical commissioning included end-to-end testing of targeting performance and subjective image quality performance in phantoms. The system has been used to image 2 patients, 1 of whom received single-fraction radiosurgery and 1 who received 3 fractions, using a relocatable head frame. Images of phantoms demonstrated soft tissue contrast visibility and submillimeter spatial resolution. A contrast difference of 35 HU was easily detected at a calibration dose of 1.2 cGy (center of head phantom). The shape of the mechanical flex vs scan angle was highly reproducible and exhibited cone beam CT image guidance system was successfully adapted to a radiosurgery unit. The system is capable of producing high-resolution images of bone and soft tissue. The system is in clinical use and provides excellent image guidance without invasive frames. Copyright © 2013 Elsevier Inc. All rights reserved.

Imaging of arteriovenous malformation following stereotactic radiosurgery

International Nuclear Information System (INIS)

Tranchida, J.V.; Mehall, C.J.; Slovis, T.L.; Lis-Planells, M.

1997-01-01

Background. Stereotactic radiosurgery allows for a high dose of focused radiation to be delivered to a small lesion such as an arteriovenous malformation (AVM). The clinical change and brain response over time to this localized high-dose radiation can be quite striking. Objective. The objective of this study to describe and analyse the imaging changes following radiotherapy for AVMs. Materials and methods. The clinical presentation and the imaging changes following radiotherapy in two patients were studied over the course of 1-2 years. Results. The imaging findings include diffuse low attenuation and contrast enhancement on CT. High-signal lesions were apparent on T2-weighted MR images with prominent contrast enhancement on T1-weighted images. Ring enhancement occurred over time. While new changes appeared over 12 months, these changes diminished during the second year. Conclusion. Radiotherapy induces inflammatory changes that are generally reversible but can lead to parenchymal destruction. These imaging changes are often nonspecific and therefore must be interpreted in light of clinical symptomatology and the time course since treatment. These patients should receive routine MR imaging within 3 months after radiosurgery with follow-up imaging at 6, 12, and 18 months. (orig.). With 8 figs

Linear accelerator based stereotactic radiosurgery with micro multi-leaf collimator : technological advancement in precision radiotherapy

International Nuclear Information System (INIS)

Dayananda, S.; Kinhikar, R.A.; Saju, Sherley; Deshpande, D.D.; Jalali, R.; Sarin, R.; Shrivastava, S.K.; Dinshaw, K.A.

2003-01-01

Stereotactic Radiosurgery (SRS) is an advancement on precision radiotherapy, in which stereo tactically guided localized high dose is delivered to the lesion (target) in a single fraction, while sparing the surrounding normal tissue. Radiosurgery has been used to treat variety of benign and malignant lesions as well as functional disorders in brain such as arteriovenous malformation (AVM), acoustic neuroma, solitary primary brain tumor, single metastasis, pituitary adenoma etc

Linear accelerator stereotactic radiosurgery for trigeminal neuralgia.

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Varela-Lema, Leonor; Lopez-Garcia, Marisa; Maceira-Rozas, Maria; Munoz-Garzon, Victor

2015-01-01

Stereotactic radiosurgery is accepted as an alternative for patients with refractory trigeminal neuralgia, but existing evidence is fundamentally based on the Gamma Knife, which is a specific device for intracranial neurosurgery, available in few facilities. Over the last decade it has been shown that the use of linear accelerators can achieve similar diagnostic accuracy and equivalent dose distribution. To assess the effectiveness and safety of linear-accelerator stereotactic radiosurgery for the treatment of patients with refractory trigeminal neuralgia. We carried out a systematic search of the literature in the main electronic databases (PubMed, Embase, ISI Web of Knowledge, Cochrane, Biomed Central, IBECS, IME, CRD) and reviewed grey literature. All original studies on the subject published in Spanish, French, English, and Portuguese were eligible for inclusion. The selection and critical assessment was carried out by 2 independent reviewers based on pre-defined criteria. In view of the impossibility of carrying out a pooled analysis, data were analyzed in a qualitative way. Eleven case series were included. In these, satisfactory pain relief (BIN I-IIIb or reduction in pain = 50) was achieved in 75% to 95.7% of the patients treated. The mean time to relief from pain ranged from 8.5 days to 3.8 months. The percentage of patients who presented with recurrences after one year of follow-up ranged from 5% to 28.8%. Facial swelling or hypoesthesia, mostly of a mild-moderate grade appeared in 7.5% - 51.9% of the patients. Complete anaesthesia dolorosa was registered in only study (5.3%). Cases of hearing loss (2.5%), brainstem edema (5.8%), and neurotrophic keratoplasty (3.5%) were also isolated. The results suggest that stereotactic radiosurgery with linear accelerators could constitute an effective and safe therapeutic alternative for drug-resistant trigeminal neuralgia. However, existing studies leave important doubts as to optimal treatment doses or the

A cerebral arteriovenous malformation grading system for gamma knife radiosurgery with the aim of early obliteration

International Nuclear Information System (INIS)

Negishi, Masatoshi; Inoue, Hiroshi K.; Hirato, Masafumi; Yokoe, Takao; Iino, Yuichi; Ohye, Chihiro; Shibazaki, Tohru

1998-01-01

Bleeding in the latency period before obliteration considerably worsens the prognosis of cerebral arteriovenous malformations (AVMs). Bleeding risk should be considered and total obliteration should performed as early as possible. In this study we investigated factors related to early obliteration following Gamma Knife radiosurgery and proposed a grading system for AVMs. Forty-six patients with cerebral AVMs followed angiographically within twelve months after Gamma Knife radiosurgery were analyzed. Four factors, volume, type (categorized by our own method), location, and marginal dose were found to be correlated with early obliteration rate. We scored these factors, and categorized the scores into a grade O to 6 Gamma Knife Score (GKS), and evaluated the obliteration rate of each grade. The total obliteration rate in twelve months according to grade was: grades 0 and 1, 61.9%; grades 2 and 3, 36.0%, grades 4 and 5, 16.7%. AVMs with a low GKS (grades 0 and 1) had a high early obliteration rate and seemed suitable for Gamma Knife radiosurgery. Since early obliteration is difficult to obtain in the high grade group, endovascular surgery should be considered to reduce the GKS before Gamma Knife radiosurgery. (author)

Development of a Prototype Robotic System for Radiosurgery with Upper Hemispherical Workspace

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Sun Young Noh

2017-01-01

Full Text Available This paper introduces a specialized robotic system under development for radiosurgery using a small-sized linear accelerator. The robotic system is a 5-DOF manipulator that can be installed above a patient to make an upper hemispherical workspace centered in a target point. In order to determine the optimal lengths of the link, we consider the requirements for the workspace of a linear accelerator for radiosurgery. A more suitable kinematic structure than conventional industrial manipulators is proposed, and the kinematic analysis is also provided. A graphic simulator is implemented and used for dynamic analysis. Based on those results, a prototype manipulator and its control system are under development.

WE-A-304-02: Strategies and Technologies for Cranial Radiosurgery Planning: Gamma Knife

International Nuclear Information System (INIS)

Schlesinger, D.

2015-01-01

The high fractional doses, stringent requirements for accuracy and precision, and surgical perspective characteristic of intracranial radiosurgery create considerations for treatment planning which are distinct from most other radiotherapy procedures. This session will introduce treatment planning techniques specific to two popular intracranial SRS modalities: Gamma Knife and MLC-based Linac. The basic treatment delivery characteristics of each device will be reviewed with a focus on how those characteristics determine the paradigm used for treatment planning. Basic techniques for treatment planning will be discussed, including considerations such as isodose selection, target and organ-at-risk definition, quality indices, and protection of critical structures. Future directions for SRS treatment planning will also be discussed. Learning Objectives: Introduce the basic physical principles of intracranial radiosurgery and how they are realized in the treatment planning paradigms for Gamma Knife and Linac radiosurgery. Demonstrate basic treatment planning techniques. Discuss metrics for evaluating SRS treatment plan quality. Discuss recent and future advances in SRS treatment planning. D. Schlesinger receives research support from Elekta, AB

WE-A-304-02: Strategies and Technologies for Cranial Radiosurgery Planning: Gamma Knife

Energy Technology Data Exchange (ETDEWEB)

Schlesinger, D. [University of Virginia Health Systems (United States)

2015-06-15

The high fractional doses, stringent requirements for accuracy and precision, and surgical perspective characteristic of intracranial radiosurgery create considerations for treatment planning which are distinct from most other radiotherapy procedures. This session will introduce treatment planning techniques specific to two popular intracranial SRS modalities: Gamma Knife and MLC-based Linac. The basic treatment delivery characteristics of each device will be reviewed with a focus on how those characteristics determine the paradigm used for treatment planning. Basic techniques for treatment planning will be discussed, including considerations such as isodose selection, target and organ-at-risk definition, quality indices, and protection of critical structures. Future directions for SRS treatment planning will also be discussed. Learning Objectives: Introduce the basic physical principles of intracranial radiosurgery and how they are realized in the treatment planning paradigms for Gamma Knife and Linac radiosurgery. Demonstrate basic treatment planning techniques. Discuss metrics for evaluating SRS treatment plan quality. Discuss recent and future advances in SRS treatment planning. D. Schlesinger receives research support from Elekta, AB.

Radiosurgery for arteriovenous malformations based on magnetic resonance angiography

International Nuclear Information System (INIS)

Mehta, Minesh; Kubsad, Shrikant; Petereit, Daniel; Turski, Patrick; Levin, Allan; Kinsella, Timothy

1993-01-01

Magnetic Resonance Angiography (MRA) was performed to establish its feasibility, compare it with standard angiography (SA), employ MRA in follow-up and semiquantify AVM flow velocity (FV). A correlative evaluation between flow velocity and response to stereotactic radiosurgery was also attempted. (author). 8 refs., 1 tab

Single-session Gamma Knife radiosurgery for optic pathway/hypothalamic gliomas.

Science.gov (United States)

El-Shehaby, Amr M N; Reda, Wael A; Abdel Karim, Khaled M; Emad Eldin, Reem M; Nabeel, Ahmed M

2016-12-01

OBJECTIVE Because of their critical and central location, it is deemed necessary to fractionate when considering irradiating optic pathway/hypothalamic gliomas. Stereotactic fractionated radiotherapy is considered safer when dealing with gliomas in this location. In this study, the safety and efficacy of single-session stereotactic radiosurgery for optic pathway/hypothalamic gliomas were reviewed. METHODS Between December 2004 and June 2014, 22 patients with optic pathway/hypothalamic gliomas were treated by single-session Gamma Knife radiosurgery. Twenty patients were available for follow-up for a minimum of 1 year after treatment. The patients were 5 to 43 years (median 16 years) of age. The tumor volume was 0.15 to 18.2 cm 3 (median 3.1 cm 3 ). The prescription dose ranged from 8 to 14 Gy (median 11.5 Gy). RESULTS The mean follow-up period was 43 months. Five tumors involved the optic nerve only, and 15 tumors involved the chiasm/hypothalamus. Two patients died during the follow-up period. The tumors shrank in 12 cases, remained stable in 6 cases, and progressed in 2 cases, thereby making the tumor control rate 90%. Vision remained stable in 12 cases, improved in 6 cases, and worsened in 2 cases in which there was tumor progression. Progression-free survival was 83% at 3 years. CONCLUSIONS The initial results indicate that single-session Gamma Knife radiosurgery is a safe and effective treatment option for optic pathway/hypothalamic gliomas.

Long-Term Results of Gamma Knife Radiosurgery for Intracranial Meningioma.

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Jang, Chang Ki; Jung, Hyun Ho; Chang, Jong Hee; Chang, Jin Woo; Park, Yong Gou; Chang, Won Seok

2015-10-01

The predominant treatment modality for meningioma is surgical resection. However, gamma knife radiosurgery is also an important treatment modality for meningioma that is small or cannot be completely removed because of its location. In this study, we evaluated the effectiveness and long-term results of radiosurgical treatment for meningioma in our institution. We studied 628 patients (130 men and 498 women) who underwent gamma knife radiosurgery for intracranial meningioma, which is radiologically diagnosed, from Jan 2008 to Nov 2012. We included patients with single lesion meningioma, and followed up after 6 months with imaging, and then at 24 months with a clinical examination. Patients with high-grade meningioma or multiple meningiomas were excluded. We analyzed each of the factors associated with progression free survival. The median patient's age was 56.8 years. Maximal dosage was 27.8 Gy and marginal dosage was 13.9 Gy. The overall tumor control rate was 95%. Twenty-eight patients (4.4%) showed evidence of tumor recurrence. Ninety-eight patients (15%) developed peritumoral edema (PTE) after gamma-knife surgery; two of them (2%) underwent surgical resections due to PTE. Nine patients had craniotomy and tumor removal after gamma knife surgery. Gamma knife surgery for intracranial meningioma has proven to be a safe and effective treatment tool with successful long-term outcomes. Gamma knife radiosurgery can be especially effective in cases of remnant meningioma after surgical resection or where PTE is not present.

Utility and limitation of radiosurgery for metastatic brain tumors

International Nuclear Information System (INIS)

Kagawa, Kota; Kiya, Katsuzo; Satoh, Hideki; Mizoue, Tatsuya; Matsushige, Toshinori; Araki, Hayato; Akimitsu, Tomohide

2003-01-01

The purpose of this study was to evaluate the utility and limitations of radiosurgery for metastatic brain lesions, and to compare the clinical results of stereotactic radiosurgery (SRS) with those of whole-brain radiation therapy (WBRT) in 45 patients with metastatic brain tumors. The patients were divided into two groups: the SRS group (22 patients) and the WBRT group (23 patients). Mean survival was not significantly different between the two groups. However, in patients with 6 or more lesions, both survival time and recurrence-free time in the SRS group were inferior to those in the WBRT group. The main complication in the SRS group was perifocal edema, while dementia was seen in the WBRT group. The bedridden period was longer in the WBRT group than in the SRS group. Death caused by brain lesions was rare in both groups. From these results, SRS preserves high quality of life longer than WBRT, but SRS should be cautiously used in patients with 6 or more lesions. (author)

SU-E-T-669: Radiosurgery Failure for Trigeminal Neuralgia: A Study of Radiographic Spatial Fidelity

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Howe, J [Associates In Medical Physics, Louisville, KY (United States); Spalding, A [Norton Cancer Institute, Louisville, Kentucky (United States)

2015-06-15

Purpose: Management of Trigeminal Neuralgia with radiosurgery is well established, but often met with limited success. Recent advancements in imaging afford improvements in target localization for radiosurgery. Methods: A Trigeminal Neuralgia radiosurgery specific protocol was established for MR enhancement of the trigeminal nerve using a CISS scan with slice spacing of 0.7mm. Computed Tomography simulation was performed using axial slices on a 40 slice CT with slice spacing of 0.6mm. These datasets were registered using a mutual information algorithm and localized in a stereotactic coordinate system. Image registration between the MR and CT was evaluated for each patient by a Medical Physicist to ensure accuracy. The dorsal root entry zone target was defined on the CISS MR by a Neurosurgeon and dose calculations performed on the localized CT. Treatment plans were reviewed and approved by a Radiation Oncologist and Neurosurgeon. Image guided radiosurgery was delivered using positioning tolerance of 0.5mm and 1°. Eight patients with Trigeminal Neuralgia were treated with this protocol. Results: Seven patients reported a favorable response to treatment with average Barrow Neurological Index pain score of four before treatment and one following treatment. Only one patient had a BNI>1 following treatment and review of the treatment plan revealed that the CISS MR was registered to the CT via a low resolution (5mm slice spacing) T2 MR. All other patients had CISS MR registered directly with the localized CT. This patient was retreated 6 months later using direct registration between CISS MR and localized CT and subsequently responded to treatment with a BNI of one. Conclusion: Frameless radiosurgery offers an effective solution to Trigeminal Neuralgia management provided appropriate technology and imaging protocols (utilizing submillimeter imaging) are established and maintained.

SU-E-T-669: Radiosurgery Failure for Trigeminal Neuralgia: A Study of Radiographic Spatial Fidelity

International Nuclear Information System (INIS)

Howe, J; Spalding, A

2015-01-01

Purpose: Management of Trigeminal Neuralgia with radiosurgery is well established, but often met with limited success. Recent advancements in imaging afford improvements in target localization for radiosurgery. Methods: A Trigeminal Neuralgia radiosurgery specific protocol was established for MR enhancement of the trigeminal nerve using a CISS scan with slice spacing of 0.7mm. Computed Tomography simulation was performed using axial slices on a 40 slice CT with slice spacing of 0.6mm. These datasets were registered using a mutual information algorithm and localized in a stereotactic coordinate system. Image registration between the MR and CT was evaluated for each patient by a Medical Physicist to ensure accuracy. The dorsal root entry zone target was defined on the CISS MR by a Neurosurgeon and dose calculations performed on the localized CT. Treatment plans were reviewed and approved by a Radiation Oncologist and Neurosurgeon. Image guided radiosurgery was delivered using positioning tolerance of 0.5mm and 1°. Eight patients with Trigeminal Neuralgia were treated with this protocol. Results: Seven patients reported a favorable response to treatment with average Barrow Neurological Index pain score of four before treatment and one following treatment. Only one patient had a BNI>1 following treatment and review of the treatment plan revealed that the CISS MR was registered to the CT via a low resolution (5mm slice spacing) T2 MR. All other patients had CISS MR registered directly with the localized CT. This patient was retreated 6 months later using direct registration between CISS MR and localized CT and subsequently responded to treatment with a BNI of one. Conclusion: Frameless radiosurgery offers an effective solution to Trigeminal Neuralgia management provided appropriate technology and imaging protocols (utilizing submillimeter imaging) are established and maintained

Gamma Knife radiosurgery for hemangioma of the cavernous sinus.

Science.gov (United States)

Lee, Cheng-Chia; Sheehan, Jason P; Kano, Hideyuki; Akpinar, Berkcan; Martinez-Alvarez, Roberto; Martinez-Moreno, Nuria; Guo, Wan-Yuo; Lunsford, L Dade; Liu, Kang-Du

2017-05-01

OBJECTIVE Cavernous sinus hemangiomas (CSHs) are rare vascular tumors. A direct microsurgical approach usually results in massive hemorrhage and incomplete tumor resection. Although stereotactic radiosurgery (SRS) has emerged as a therapeutic alternative to microsurgery, outcome studies are few. Authors of the present study evaluated the role of SRS for CSH. METHODS An international multicenter study was conducted to review outcome data in 31 patients with CSH. Eleven patients had initial microsurgery before SRS, and the other 20 patients (64.5%) underwent Gamma Knife SRS as the primary management for their CSH. Median age at the time of radiosurgery was 47 years, and 77.4% of patients had cranial nerve dysfunction before SRS. Patients received a median tumor margin dose of 12.6 Gy (range 12-19 Gy) at a median isodose of 55%. RESULTS Tumor regression was confirmed by imaging in all 31 patients, and all patients had greater than 50% reduction in tumor volume at 6 months post-SRS. No patient had delayed tumor growth, new cranial neuropathy, visual function deterioration, adverse radiation effects, or hypopituitarism after SRS. Twenty-four patients had presented with cranial nerve disorders before SRS, and 6 (25%) of them had gradual improvement. Four (66.7%) of the 6 patients with orbital symptoms had symptomatic relief at the last follow-up. CONCLUSIONS Stereotactic radiosurgery was effective in reducing the volume of CSH and attaining long-term tumor control in all patients at a median of 40 months. The authors' experience suggests that SRS is a reasonable primary and adjuvant treatment modality for patients in whom a CSH is diagnosed.

Gamma radiosurgery combined with trans-sphenoidal surgery for pituitary tumor involved to the cavernous sinus

International Nuclear Information System (INIS)

Ikeda, Hidetoshi; Yoshimoto, Takashi; Shirokura, Hidefumi.

1995-01-01

Ten patients (2 males and 8 females with an average age of 39 years) were treated with combined trans-sphenoidal surgery and gamma radiosurgery for pituitary tumor involved to the cavernous sinus. A Follow-up period ranged from 7 to 29 months, with a mean of 21 months. Therapeutic effects were assessed using magnetic resonance imaging (MRI) every 3 months, endocrine examination, optical examination for visual field, and auditory test. Pituitary tumor after radiosurgery was shown as hypointensity on T1-weighted images and hyperintensity on T2-weighted images. Tumor response could be classified on MRI into (1) a remarkably decreased tumor in size with increased contrast enhancement (n=6), (2) a remarkably decreased tumor in size with unchanged contrast enhancement (n=one), (3) a slightly decreased tumor in size with increased spotted contrast enhancement (n=2), and (4) unchanged tumor in size with decreased contrast enhancement (n=one). Of 6 Type 1 patients, 5 had growth hormone production. Growth hormone production tended to be associated with favorable response to radiosurgery. In 3 patients who showed endocrinologically favorable response (such as increased growth hormone in blood and somatomedin C value), complete regression of tumor was achieved at a 20-month follow-up period. Radiosurgery also seemed to be useful for treating hormone active tumors. (N.K.)

WE-G-BRA-08: Failure Modes and Effects Analysis (FMEA) for Gamma Knife Radiosurgery

International Nuclear Information System (INIS)

Xu, Y; Bhatnagar, J; Bednarz, G; Flickinger, J; Arai, Y; Huq, M Saiful; Vacsulka, J; Monaco, E; Niranjan, A; Lunsford, L Dade; Feng, W

2015-01-01

Purpose: To perform a failure modes and effects analysis (FMEA) study for Gamma Knife (GK) radiosurgery processes at our institution based on our experience with the treatment of more than 13,000 patients. Methods: A team consisting of medical physicists, nurses, radiation oncologists, neurosurgeons at the University of Pittsburgh Medical Center and an external physicist expert was formed for the FMEA study. A process tree and a failure mode table were created for the GK procedures using the Leksell GK Perfexion and 4C units. Three scores for the probability of occurrence (O), the severity (S), and the probability of no detection (D) for failure modes were assigned to each failure mode by each professional on a scale from 1 to 10. The risk priority number (RPN) for each failure mode was then calculated (RPN = OxSxD) as the average scores from all data sets collected. Results: The established process tree for GK radiosurgery consists of 10 sub-processes and 53 steps, including a sub-process for frame placement and 11 steps that are directly related to the frame-based nature of the GK radiosurgery. Out of the 86 failure modes identified, 40 failure modes are GK specific, caused by the potential for inappropriate use of the radiosurgery head frame, the imaging fiducial boxes, the GK helmets and plugs, and the GammaPlan treatment planning system. The other 46 failure modes are associated with the registration, imaging, image transfer, contouring processes that are common for all radiation therapy techniques. The failure modes with the highest hazard scores are related to imperfect frame adaptor attachment, bad fiducial box assembly, overlooked target areas, inaccurate previous treatment information and excessive patient movement during MRI scan. Conclusion: The implementation of the FMEA approach for Gamma Knife radiosurgery enabled deeper understanding of the overall process among all professionals involved in the care of the patient and helped identify potential

An improved tracking framework for ultrasound probe localization in image-guided radiosurgery

Directory of Open Access Journals (Sweden)

Ipsen Svenja

2016-09-01

Full Text Available Real-time target localization with ultrasound holds high potential for image guidance and motion compensation in radiosurgery due to its non-invasive image acquisition free from ionizing radiation. However, a two-step localization has to be performed when integrating ultrasound into the existing radiosurgery workflow. In addition to target localization inside the ultrasound volume, the probe itself has to be localized in order to transform the target position into treatment room coordinates. By adapting existing camera calibration tools, we have developed a method to extend the stereoscopic X-ray tracking system of a radiosurgery platform in order to locate objects such as marker geometries with six degrees of freedom. The calibration was performed with 0.1 mm reprojection error. By using the full area of the flat-panel detectors without pre-processing the extended software increased the tracking volume and resolution by up to 80%, substantially improving patient localization and marker detectability. Furthermore, marker-tracking showed sub-millimeter accuracy and rotational errors below 0.1°. This demonstrates that the developed extension framework can accurately localize marker geometries using an integrated X-ray system, establishing the link for the integration of real-time ultrasound image guidance into the existing system.

Risk factors for local failure requiring salvage neurosurgery after radiosurgery for brain metastases

International Nuclear Information System (INIS)

Weltman, Eduardo; Hanriot, Rodrigo de Morais; Prisco, Flavio Eduardo; Nadalin, Wladimir; Brandt, Reynaldo Andre; Moreira, Frederico Rafael

2004-01-01

Objective: the aim of this study is to select the risk factors for local failure requiring salvage neurosurgery in patients with brain metastases treated with stereotactic radiosurgery in a single institution. Methods: the follow-up of 123 patients, with 255 brain metastases treated with radiosurgery at the Radiation Oncology Department of the Hospital Israelita Albert Einstein from July 1993 to August 2001, was retrospectively analyzed. The criteria for salvage neurosurgery were tumor volume enlargement, or tumor persistence leading to severe neurological symptoms, life threatening situation or critical steroid dependence. We considered the case as local failure when the histopathologic evaluation showed morphologically preserved cancer cells (tumor recurrence, persistence or progression). We applied the Fisher's exact test to evaluate the statistical correlation between local failure and primary tumor histology, volume of the brain metastases, prescribed radiosurgery dose, and whole brain radiotherapy. Results: fourteen of 123 patients (11%) underwent salvage neurosurgery. Histology showed preserved cancer cells with necrosis and/or bleeding in 11 cases (9% of the total accrual), and only necrosis with or without bleeding (without preserved cancer cells) in three cases. The primary tumor histology among the 11 patients considered with active neoplasia was malignant melanoma in five cases (21% of the patients with melanoma), breast adenocarcinoma in three (16% of the patients with breast cancer), and other histology in the remaining three. Breast cancer diagnosis, non-elective whole brain irradiation, volume of the brain metastases, and the prescribed radiosurgery dose did not correlate with the risk of local failure. Patients treated with elective whole brain radiotherapy showed fewer local failures, when compared to all patients receiving whole brain radiotherapy, and to the patients not receiving this treatment, with incidence of failure in 4%,7% and 14

Gamma knife radiosurgery for acoustic neurinomas. Pt. 1. The analysis of tumor control

International Nuclear Information System (INIS)

Fukuoka, Seiji; Seo, Yoshinobu; Nakagawara, Jyoji

1997-01-01

Forty-three patients with the unilateral type of acoustic neurinoma who were treated with gamma knife radiosurgery were analyzed from the viewpoint of tumor control. The follow-up period ranged from 22 to 55 months. The tumors were treated with marginal radiation doses of 9-15 Gy with multiple isocenters. The actuarial tumor reduction rates were 42% at one year, 75% at 2 years, and 92% at 3 years after gamma knife radiosurgery. Transient tumor expansion was seen in 33% of patients, which correlated with previous surgical cases. The present control rate was 91%. SPECT was performed on 15 selected patients before and 1 year and 2 years after gamma knife radiosurgery. 201 TlCl SPECT was used to determine tumor viability, and the early and delayed 99m Tc-DTPA-HSA-D SPECT images were used to assess tumor vascularity and permeability, respectively. The Tl index and HSA-D index of the delayed images were not significantly different from the respective preoperative values. However, there was a statistically significant decrease in the HSA-D index of the early images 1 year after treatment. A statistically significant reduction in tumor volume was seen 2 years after treatment in these 15 patients, meaning that a reduction in tumor vascularity was followed by a reduction in tumor size. One patient underwent surgical excision of the tumor 18 months after gamma knife radiosurgery because the tumor had expanded and resulted in cerebellar ataxia. Histopathologic investigation revealed the presence of some tumor cells with irregularly shaped nuclei and marked intimal thickening or obliteration of the tumor vessels. (K.H.)

Linear Accelerator Stereotactic Radiosurgery of Central Nervous System Arteriovenous Malformations: A 15-Year Analysis of Outcome-Related Factors in a Single Tertiary Center.

Science.gov (United States)

Thenier-Villa, José Luis; Galárraga-Campoverde, Raúl Alejandro; Martínez Rolán, Rosa María; De La Lama Zaragoza, Adolfo Ramón; Martínez Cueto, Pedro; Muñoz Garzón, Víctor; Salgado Fernández, Manuel; Conde Alonso, Cesáreo

2017-07-01

Linear accelerator stereotactic radiosurgery is one of the modalities available for the treatment of central nervous system arteriovenous malformations (AVMs). The aim of this study was to describe our 15-year experience with this technique in a single tertiary center and the analysis of outcome-related factors. From 1998 to 2013, 195 patients were treated with linear accelerator-based radiosurgery; we conducted a retrospective study collecting patient- and AVM-related variables. Treatment outcomes were obliteration, posttreatment hemorrhage, symptomatic radiation-induced changes, and 3-year neurologic status. We also analyzed prognostic factors of each outcome and predictability analysis of 5 scales: Spetzler-Martin grade, Lawton-Young supplementary and Lawton combined scores, radiosurgery-based AVM score, Virginia Radiosurgery AVM Scale, and Heidelberg score. Overall obliteration rate was 81%. Nidus diameter and venous drainage were predictive of obliteration (P linear accelerator-based radiosurgery is a useful, valid, effective, and safe modality for treatment of brain AVMs. Copyright © 2017 Elsevier Inc. All rights reserved.

A case of acoustic neurinoma associated with chronic subdural hematoma after gamma knife radiosurgery

International Nuclear Information System (INIS)

Sho, Atsuko; Asaeda, Masahiro; Ohtake, Minoru

2002-01-01

A 72-year-old female presented with a unique case of acoustic neurinoma with a cystic component followed by the chronic subdural hematoma manifesting as trigeminal neuralgia, facial palsy and trunchal ataxia 7 months after gamma knife radiosurgery. Magnetic resonance imaging demonstrated a loss of central contrast enhancement at the postoperative residual tumor mass and a large cyst associated with a hematoma in the subdural space. A right suboccipital craniectomy was performed. A biopsy of the mass and the membrane was performed following aspiration of the brown-reddish fluid collection. The histological diagnosis was acoustic neurinoma with a hemorrhagic necrosis. The membranous tissue mimicked an outer membrane obtained from chronic subdural hematoma. The postoperative course was satisfactory and preoperative symptom have been alleviated. In this case, the chronic subdural hematoma occurred at posterior fossa during the development of cysts caused by the radiosurgery, because the subdural space had been connected with the subarachnoid space after the first operation. The development of cysts or hematoma should be taken into consideration as possible complications following treatment with gamma knife radiosurgery for acoustic neurinomas. (author)

A case of acoustic neurinoma associated with chronic subdural hematoma after gamma knife radiosurgery

Energy Technology Data Exchange (ETDEWEB)

Sho, Atsuko; Asaeda, Masahiro; Ohtake, Minoru [Tottori Univ., Yonago (Japan). Inst. of Neurological Sciences] [and others

2002-09-01

A 72-year-old female presented with a unique case of acoustic neurinoma with a cystic component followed by the chronic subdural hematoma manifesting as trigeminal neuralgia, facial palsy and trunchal ataxia 7 months after gamma knife radiosurgery. Magnetic resonance imaging demonstrated a loss of central contrast enhancement at the postoperative residual tumor mass and a large cyst associated with a hematoma in the subdural space. A right suboccipital craniectomy was performed. A biopsy of the mass and the membrane was performed following aspiration of the brown-reddish fluid collection. The histological diagnosis was acoustic neurinoma with a hemorrhagic necrosis. The membranous tissue mimicked an outer membrane obtained from chronic subdural hematoma. The postoperative course was satisfactory and preoperative symptom have been alleviated. In this case, the chronic subdural hematoma occurred at posterior fossa during the development of cysts caused by the radiosurgery, because the subdural space had been connected with the subarachnoid space after the first operation. The development of cysts or hematoma should be taken into consideration as possible complications following treatment with gamma knife radiosurgery for acoustic neurinomas. (author)

WE-A-304-01: Strategies and Technologies for Cranial Radiosurgery Planning: MLC-Based Linac

Energy Technology Data Exchange (ETDEWEB)

Kim, G. [University of California, San Diego (United States)

2015-06-15

The high fractional doses, stringent requirements for accuracy and precision, and surgical perspective characteristic of intracranial radiosurgery create considerations for treatment planning which are distinct from most other radiotherapy procedures. This session will introduce treatment planning techniques specific to two popular intracranial SRS modalities: Gamma Knife and MLC-based Linac. The basic treatment delivery characteristics of each device will be reviewed with a focus on how those characteristics determine the paradigm used for treatment planning. Basic techniques for treatment planning will be discussed, including considerations such as isodose selection, target and organ-at-risk definition, quality indices, and protection of critical structures. Future directions for SRS treatment planning will also be discussed. Learning Objectives: Introduce the basic physical principles of intracranial radiosurgery and how they are realized in the treatment planning paradigms for Gamma Knife and Linac radiosurgery. Demonstrate basic treatment planning techniques. Discuss metrics for evaluating SRS treatment plan quality. Discuss recent and future advances in SRS treatment planning. D. Schlesinger receives research support from Elekta, AB.

WE-A-304-01: Strategies and Technologies for Cranial Radiosurgery Planning: MLC-Based Linac

International Nuclear Information System (INIS)

Kim, G.

2015-01-01

The high fractional doses, stringent requirements for accuracy and precision, and surgical perspective characteristic of intracranial radiosurgery create considerations for treatment planning which are distinct from most other radiotherapy procedures. This session will introduce treatment planning techniques specific to two popular intracranial SRS modalities: Gamma Knife and MLC-based Linac. The basic treatment delivery characteristics of each device will be reviewed with a focus on how those characteristics determine the paradigm used for treatment planning. Basic techniques for treatment planning will be discussed, including considerations such as isodose selection, target and organ-at-risk definition, quality indices, and protection of critical structures. Future directions for SRS treatment planning will also be discussed. Learning Objectives: Introduce the basic physical principles of intracranial radiosurgery and how they are realized in the treatment planning paradigms for Gamma Knife and Linac radiosurgery. Demonstrate basic treatment planning techniques. Discuss metrics for evaluating SRS treatment plan quality. Discuss recent and future advances in SRS treatment planning. D. Schlesinger receives research support from Elekta, AB

Repeat Stereotactic Radiosurgery for Acoustic Neuromas

International Nuclear Information System (INIS)

Kano, Hideyuki; Kondziolka, Douglas; Niranjan, Ajay M.Ch.; Flannery, Thomas J.; Flickinger, John C.; Lunsford, L. Dade

2010-01-01

Purpose: To evaluate the outcome of repeat stereotactic radiosurgery (SRS) for acoustic neuromas, we assessed tumor control, clinical outcomes, and the risk of adverse radiation effects in patients whose tumors progressed after initial management. Methods and Materials: During a 21-year experience at our center, 1,352 patients underwent SRS as management for their acoustic neuromas. We retrospectively identified 6 patients who underwent SRS twice for the same tumor. The median patient age was 47 years (range, 35-71 years). All patients had imaging evidence of tumor progression despite initial SRS. One patient also had incomplete surgical resection after initial SRS. All patients were deaf at the time of the second SRS. The median radiosurgery target volume at the time of the initial SRS was 0.5 cc and was 2.1 cc at the time of the second SRS. The median margin dose at the time of the initial SRS was 13 Gy and was 11 Gy at the time of the second SRS. The median interval between initial SRS and repeat SRS was 63 months (range, 25-169 months). Results: At a median follow-up of 29 months after the second SRS (range, 13-71 months), tumor control or regression was achieved in all 6 patients. No patient developed symptomatic adverse radiation effects or new neurological symptoms after the second SRS. Conclusions: With this limited experience, we found that repeat SRS for a persistently enlarging acoustic neuroma can be performed safely and effectively.

Stereotactic gamma radiosurgery of brain tumors

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Tatsuya; Kida, Yoshihisa; Tanaka, Takayuki; Oyama, Hirofumi; Yoshida, Kazuo; Maesawa, Satoshi; Kai, Osamu; Nakamura, Mototoshi; Arahata, Masashige [Komaki City Hospital, Aichi (Japan)

1996-06-01

One thousand cases with various head and neck diseases have been treated by gamma radiosurgery at Komaki City Hospital since May 1991. Five hundred and sixty-eight out of 1,000 cases were neoplastic lesions which consisted of 173 cases of neurinoma, 108 of metastatic tumors, 103 of meningioma, 69 of gliomas, 27 of pituitary adenoma, 26 of craniopharyngioma, 13 of pineal tumors, 11 of chordoma, 6 of malignant lymphoma, 5 of hemangioblastoma and so on. The most effective result has been shown in metastatic brain tumors. The complete response (disappearance of the lesion) was obtained in more than 50% of the treated lesions, and the control rate of 85% was maintained for more than 12 months. Next effective results were shown in craniopharyngioma, malignant pineal tumors and malignant lymphoma. There was a group which showed moderate response but no tumor disappearance. Those were pituitary adenoma, acoustic neurinoma, meningioma and chordoma. Gliomas showed less response and even progression of tumor at relatively higher rate. It has been found that malignant gliomas showed difficult control of the tumor and progression rate of 70%, while benign gliomas showed the control rate of more than 90%. Besides intracranial lesions, malignant skull base tumors such as chordoma, naso-pharyngeal cancer, adenoid cystic cancer showed better response to gamma radiosurgery and higher control rate for longer period of time with high QOL compaired to conventional irradiation. (author)

Dosimetric performance and array assessment of plastic scintillation detectors for stereotactic radiosurgery quality assurance.

Science.gov (United States)

Gagnon, Jean-Christophe; Thériault, Dany; Guillot, Mathieu; Archambault, Louis; Beddar, Sam; Gingras, Luc; Beaulieu, Luc

2012-01-01

To compare the performance of plastic scintillation detectors (PSD) for quality assurance (QA) in stereotactic radiosurgery conditions to a microion-chamber (IC), Gafchromic EBT2 films, 60 008 shielded photon diode (SD) and unshielded diodes (UD), and assess a new 2D crosshair array prototype adapted to small field dosimetry. The PSD consists of a 1 mm diameter by 1 mm long scintillating fiber (BCF-60, Saint-Gobain, Inc.) coupled to a polymethyl-methacrylate optical fiber (Eska premier, Mitsubishi Rayon Co., Ltd., Tokyo, Japan). Output factors (S(c,p)) for apertures used in radiosurgery ranging from 4 to 40 mm in diameter have been measured. The PSD crosshair array (PSDCA) is a water equivalent device made up of 49 PSDs contained in a 1.63 cm radius area. Dose profiles measurements were taken for radiosurgery fields using the PSDCA and were compared to other dosimeters. Moreover, a typical stereotactic radiosurgery treatment using four noncoplanar arcs was delivered on a spherical phantom in which UD, IC, or PSD was placed. Using the Xknife planning system (Integra Radionics Burlington, MA), 15 Gy was prescribed at the isocenter, where each detector was positioned. Output Factors measured by the PSD have a mean difference of 1.3% with Gafchromic EBT2 when normalized to a 10 × 10 cm(2) field, and 1.0% when compared with UD measurements normalized to the 35 mm diameter cone. Dose profiles taken with the PSD crosshair array agreed with other single detectors dose profiles in spite of the presence of the 49 PSDs. Gamma values comparing 1D dose profiles obtained with PSD crosshair array with Gafchromic EBT2 and UD measured profiles shows 98.3% and 100.0%, respectively, of detector passing the gamma acceptance criteria of 0.3 mm and 2%. The dose measured by the PSD for a complete stereotactic radiosurgery treatment is comparable to the planned dose corrected for its SD-based S(c,p) within 1.4% and 0.7% for 5 and 35 mm diameter cone, respectively. Furthermore

Dosimetric performance and array assessment of plastic scintillation detectors for stereotactic radiosurgery quality assurance

Energy Technology Data Exchange (ETDEWEB)

Gagnon, Jean-Christophe; Theriault, Dany; Guillot, Mathieu; Archambault, Louis; Beddar, Sam; Gingras, Luc; Beaulieu, Luc [Departement de Physique, de Genie Physique et d' Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Departement de Physique, de Genie Physique et d' Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada); Department of Radiation Physics, Unit 94, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); Departement de Physique, de Genie Physique et d' Optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada) and Departement de Radio-Oncologie, Hotel-Dieu de Quebec, Centre Hospitalier Universitaire de Quebec, Quebec G1R 2J6 (Canada)

2012-01-15

Purpose: To compare the performance of plastic scintillation detectors (PSD) for quality assurance (QA) in stereotactic radiosurgery conditions to a microion-chamber (IC), Gafchromic EBT2 films, 60 008 shielded photon diode (SD) and unshielded diodes (UD), and assess a new 2D crosshair array prototype adapted to small field dosimetry. Methods: The PSD consists of a 1 mm diameter by 1 mm long scintillating fiber (BCF-60, Saint-Gobain, Inc.) coupled to a polymethyl-methacrylate optical fiber (Eska premier, Mitsubishi Rayon Co., Ltd., Tokyo, Japan). Output factors (S{sub c,p}) for apertures used in radiosurgery ranging from 4 to 40 mm in diameter have been measured. The PSD crosshair array (PSDCA) is a water equivalent device made up of 49 PSDs contained in a 1.63 cm radius area. Dose profiles measurements were taken for radiosurgery fields using the PSDCA and were compared to other dosimeters. Moreover, a typical stereotactic radiosurgery treatment using four noncoplanar arcs was delivered on a spherical phantom in which UD, IC, or PSD was placed. Using the Xknife planning system (Integra Radionics Burlington, MA), 15 Gy was prescribed at the isocenter, where each detector was positioned. Results: Output Factors measured by the PSD have a mean difference of 1.3% with Gafchromic EBT2 when normalized to a 10 x 10 cm{sup 2} field, and 1.0% when compared with UD measurements normalized to the 35 mm diameter cone. Dose profiles taken with the PSD crosshair array agreed with other single detectors dose profiles in spite of the presence of the 49 PSDs. Gamma values comparing 1D dose profiles obtained with PSD crosshair array with Gafchromic EBT2 and UD measured profiles shows 98.3% and 100.0%, respectively, of detector passing the gamma acceptance criteria of 0.3 mm and 2%. The dose measured by the PSD for a complete stereotactic radiosurgery treatment is comparable to the planned dose corrected for its SD-based S{sub c,p} within 1.4% and 0.7% for 5 and 35 mm diameter cone

Dosimetric performance and array assessment of plastic scintillation detectors for stereotactic radiosurgery quality assurance

International Nuclear Information System (INIS)

Gagnon, Jean-Christophe; Theriault, Dany; Guillot, Mathieu; Archambault, Louis; Beddar, Sam; Gingras, Luc; Beaulieu, Luc

2012-01-01

Purpose: To compare the performance of plastic scintillation detectors (PSD) for quality assurance (QA) in stereotactic radiosurgery conditions to a microion-chamber (IC), Gafchromic EBT2 films, 60 008 shielded photon diode (SD) and unshielded diodes (UD), and assess a new 2D crosshair array prototype adapted to small field dosimetry. Methods: The PSD consists of a 1 mm diameter by 1 mm long scintillating fiber (BCF-60, Saint-Gobain, Inc.) coupled to a polymethyl-methacrylate optical fiber (Eska premier, Mitsubishi Rayon Co., Ltd., Tokyo, Japan). Output factors (S c,p ) for apertures used in radiosurgery ranging from 4 to 40 mm in diameter have been measured. The PSD crosshair array (PSDCA) is a water equivalent device made up of 49 PSDs contained in a 1.63 cm radius area. Dose profiles measurements were taken for radiosurgery fields using the PSDCA and were compared to other dosimeters. Moreover, a typical stereotactic radiosurgery treatment using four noncoplanar arcs was delivered on a spherical phantom in which UD, IC, or PSD was placed. Using the Xknife planning system (Integra Radionics Burlington, MA), 15 Gy was prescribed at the isocenter, where each detector was positioned. Results: Output Factors measured by the PSD have a mean difference of 1.3% with Gafchromic EBT2 when normalized to a 10 x 10 cm 2 field, and 1.0% when compared with UD measurements normalized to the 35 mm diameter cone. Dose profiles taken with the PSD crosshair array agreed with other single detectors dose profiles in spite of the presence of the 49 PSDs. Gamma values comparing 1D dose profiles obtained with PSD crosshair array with Gafchromic EBT2 and UD measured profiles shows 98.3% and 100.0%, respectively, of detector passing the gamma acceptance criteria of 0.3 mm and 2%. The dose measured by the PSD for a complete stereotactic radiosurgery treatment is comparable to the planned dose corrected for its SD-based S c,p within 1.4% and 0.7% for 5 and 35 mm diameter cone, respectively

The surgical treatment strategy and results of parasellar meningiomas in the era of radiosurgery

International Nuclear Information System (INIS)

Iwai, Yoshiyasu; Yamanaka, Kazuhiro; Morikawa, Toshie; Ishiguro, Tomoya; Honda, Yuji; Matsuzaka, Yasuhiro; Komiyama, Masaki; Yasui, Toshihiro

2003-01-01

We evaluated the surgical treatment results of parasellar meningiomas in the era of radiosurgery. We treated 24 patients of parasellar meningiomas surgically. The median age was 60 yrs (ranging from 29 to 82 yrs). The most common tumor location was the sphenoid ridge in 12 patients and the tuberculum sellae in 7 patients. The pterional approach using fronto-temporal craniotomy was performed for all patients. The residual or recurrent tumors were treated by gamma knife radiosurgery (GKS). We are able to follow up these cases for a median of 3.8 yrs (ranging from 1 to 8 yrs) after the operations. The radicality of tumor resection was Simpson grade II in 13 patients (54%), grade III in 3 patients (13%) and grade IV in 7 patients (33%). Clinical improvement was achieved in 81% of the patients. Of the patients who had visual disturbance preoperatively, 8 patients (73%) showed improvement, but 3 patients suffered deterioration postoperatively. None of the patients died. One patient suffered transient memory disturbance and one patient suffered mild facial numbness postoperatively. Boost radiosurgery for the residual tumors was performed for six patients and tumor growth control was able to be achieved in all patients, with a median of 3.1 years follow-up period (ranging from 0.5 to 6 yrs). Five patients with tumor regrowth or recurrence were treated by GKS. We recommend fronto-temporal craniotomy with nonradical resection for parasellar meningiomas and radiosurgery for residual and recurrent tumors. This strategy will achieve good functional outcome with long-term tumor growth control. (author)

Morphological and functional MRI, MRS, perfusion and diffusion changes after radiosurgery of brain metastasis

International Nuclear Information System (INIS)

Kang, Tae Wook; Kim, Sung Tae; Byun, Hong Sik; Jeon, Pyoung; Kim, Keonha; Kim, Hyungjin; Lee, Jung II

2009-01-01

Radiosurgery is a noninvasive procedure where spatially accurate and highly conformal doses of radiation are targeted at brain lesions with an ablative intent. Recently, radiosurgery has been established as an effective technique for local treatment of brain metastasis. After radiosurgery, magnetic resonance (MR) imaging plays an important role in the assessment of the therapeutic response and of any complications. The therapeutic approach depends on the imaging findings obtained after radiosurgery, which have a role in the decision making to perform additional invasive modalities (repeat resection, biopsy) to obtain a definite diagnosis and to improve the survival of patients. Conventional MR imaging findings are mainly based on morphological alterations of tumors. However, there are variable imaging findings of radiation-induced changes including radiation necrosis in the brain. Radiologists are sometimes confused by radiation-induced injuries, including radiation necrosis, that are seen on conventional MR imaging. The pattern of abnormal enhancement on follow-up conventional MR imaging closely mimics that of a recurrent brain metastasis. So, classifying newly developed abnormal enhancing lesions in follow-up of treated brain metastasis with correct diagnosis is one of the key goals in neuro-oncologic imaging. To overcome limitations of the use of morphology-based conventional MR imaging, several physiological-based functional MR imaging methods have been used, namely diffusion-weighted imaging, perfusion MR imaging, and proton MR spectroscopy, for the detection of hemodynamic, metabolic, and cellular alterations. These imaging modalities provide additional information to allow clinicians to make proper decisions regarding patient treatment.

Monte Carlo dose distributions for radiosurgery

International Nuclear Information System (INIS)

Perucha, M.; Leal, A.; Rincon, M.; Carrasco, E.

2001-01-01

The precision of Radiosurgery Treatment planning systems is limited by the approximations of their algorithms and by their dosimetrical input data. This fact is especially important in small fields. However, the Monte Carlo methods is an accurate alternative as it considers every aspect of particle transport. In this work an acoustic neurinoma is studied by comparing the dose distribution of both a planning system and Monte Carlo. Relative shifts have been measured and furthermore, Dose-Volume Histograms have been calculated for target and adjacent organs at risk. (orig.)

Radiosurgery supported in the lineal accelerator for the acoustic neuroma treatment

International Nuclear Information System (INIS)

Santos Ortega, M.; Gutierrez Diaz, J.; Rodriguez Villaba, S.; Garcia Berrocal, I.; Samblas Garcia, J.; Bustos Perez de Salcedo, J.C.; Ortiz de Urbina, D.; Donckaster Clavero, G.; Delgado Rodriguez, J.M.; Sansivirini Valle, F.

1996-01-01

Radiosurgery becomes in a great interest technique in acoustic neuroma treatments. We present preliminary results over 74 neurinomas patients in our Unit. From August 1991 to August 1994, 74 consecutive patients with acoustic neuromas, median age 50 yrs. has been treated in our Unit. A SRS 200 radiosurgery system was employed using a 6 MV photon beam Linear Accelerator as radiation source. In every case treatment dose was lesser than 18 gy (14-16 Gy). Before treatment all patients were evaluated with MRI and neurological examination, acoustic test included. This screening was repeated each six months during the follow up. Tumoral control was defined both, as no changes or diminishing in tumoral size, observed in sequential MRI studies with gadolinium and comparable techniques. The median fallow up is 18 months. Tumor control is 88,5%. In 30 patients control means dismissing in tumoral size. In 10 patients tumoral progression was evident, in a half of their a neurofibromatosis type II was previously diagnosed. The neurological function during the follow up shown improve or estabilitation in symptoms, for 85% VII pair patients, 83% in VII pair patients, 86% in V pair patients and 83% in cerebellar disfunction patients. Although preliminaries, this dates showing the efficacy of radiosurgery in tumoral control of patients with neurinomas with doses laser than 18 Gy. This dose are safe with toxicities around 15%, mainly in transitory presentations. (Auhtor) 67 refs

Neuropsychological results after gamma knife radiosurgery for mesial temporal lobe epilepsy.

Science.gov (United States)

Vojtěch, Zdeněk; Krámská, Lenka; Malíková, Hana; Stará, Michaela; Liščák, Roman

2015-01-01

The aim of this study is to summarize our experience with neuropsychological changes after radiosurgical treatment for mesial temporal lobe epilepsy and subsequent surgery due to insufficient seizure control. Between November 1995 and May 1999, 14 patients underwent radiosurgical entorhinoamygdalohippocampectomy with a marginal dose of 18, 20 or 25 Gy to the 50% isodose. 9 of these patients subsequently underwent surgery. We compared Memory Quotients and Intelligence Quotients before and after the interventions. We found a slight, but nonsignificant decline in intelligence and memory quotients one year after GKRS. Two years after radiosurgery there were no significant changes in any of the quotients. After surgery, we found significant increase in Global and Visual MQ, (pmemory and intelligence performance after surgery. Epilepsy surgery after unsuccessful radiosurgery could lead to improvements in cognitive functions in patients with mesial temporal lobe epilepsy.

An integrated logistic formula for prediction of complications from radiosurgery

International Nuclear Information System (INIS)

Flickinger, J.C.

1989-01-01

An integrated logistic model for predicting the probability of complications when small volumes of tissue receive an inhomogeneous radiation dose is described. This model can be used with either an exponential or linear quadratic correction for dose per fraction and time. Both the exponential and linear quadratic versions of this integrated logistic formula provide reasonable estimates of the tolerance of brain to radiosurgical dose distributions where there are small volumes of brain receiving high radiation doses and larger volumes receiving lower doses. This makes it possible to predict the probability of complications from stereotactic radiosurgery, as well as combinations of fractionated large volume irradiation with a radiosurgical boost. Complication probabilities predicted for single fraction radiosurgery with the Leksell Gamma Unit using 4, 8, 14, and 18 mm diameter collimators as well as for whole brain irradiation combined with a radiosurgical boost are presented. The exponential and linear quadratic versions of the integrated logistic formula provide useful methods of calculating the probability of complications from radiosurgical treatment

Hybrid surgery-radiosurgery therapy for metastatic epidural spinal cord compression: A prospective evaluation using patient-reported outcomes.

Science.gov (United States)

Barzilai, Ori; Amato, Mary-Kate; McLaughlin, Lily; Reiner, Anne S; Ogilvie, Shahiba Q; Lis, Eric; Yamada, Yoshiya; Bilsky, Mark H; Laufer, Ilya

2018-05-01

Patient-reported outcomes (PRO) represent an important measure of cancer therapy effect. For patients with metastatic epidural spinal cord compression (MESCC), hybrid therapy using separation surgery and stereotactic radiosurgery preserves neurologic function and provides tumor control. There is currently a paucity of data reporting PRO after such combined modality therapy for MESCC. Delineation of hybrid surgery-radiosurgery therapy effect on PRO validates the hybrid approach as an effective therapy resulting in meaningful symptom relief. Brief Pain Inventory (BPI) and MD Anderson Symptom Inventory-Spine Tumor (MDASI-SP), PROs validated in the cancer population, were prospectively collected. Patients with MESCC who underwent separation surgery followed by stereotactic radiosurgery were included. Separation surgery included a posterolateral approach without extensive cytoreductive tumor excision. A median postoperative radiosurgery dose of 2700 cGy was delivered. The change in PRO 3 months after the hybrid therapy represented the primary study outcome. Preoperative and postoperative evaluations were analyzed using the Wilcoxon signed-rank test for matched pairs. One hundred eleven patients were included. Hybrid therapy resulted in a significant reduction in the BPI items "worst" and "right now" pain ( P < .0001), and in all BPI constructs (severity, interference with daily activities, and pain experience, P < .001). The MDASI-SP demonstrated reduction in spine-specific pain severity and interference with general activity ( P < .001), along with decreased symptom interference ( P < .001). Validated PRO instruments showed that in patients with MESCC, hybrid therapy with separation surgery and radiosurgery results in a significant decrease in pain severity and symptom interference. These prospective data confirm the benefit of hybrid therapy for treatment of MESCC and should facilitate referral of patients with MESCC for surgical evaluation.

Gamma knife radiosurgery for secreting pituitary tumors

International Nuclear Information System (INIS)

Noren, G.; Jackson, I.M.D.; Chougule, P.; Zheng, Z.; Epstein, M.H.

1998-01-01

Transsphenoidal surgery usually represents first line treatment for pituitary adenomas with the aim of removing the tumor, decompressing the optic apparatus and, in secreting tumors, eliminating the hypersecretion. Gamma Knife radiosurgery is indicated for tumor remnants or recurrences in or above the sella including those invading the cavernous sinus and also as initial treatment in patients who are unable to tolerate an open surgical procedure and where medication has failed. In this study, the target definition was retrospectively studied and when necessary corrected in 10 acromegalic patients, 8 with Cushing's disease, and 12 with prolactinomas undergoing Gamma Knife radiosurgery. The dose plan was analyzed and the volume of the target covered by a minimum of 15, 20, 25, 30 and 35 Gy was estimated. A dose/volume profile for each treatment was created and correlated to the endocrinological and clinical outcome. Cure, according to strict endocrinological criteria, was seen in 6 of the acromegalic patients, in 2 of the patients with ACTH hypersecretion, and in 2 of the patients with prolactinomas. Analysis of these profiles, also for the patients with partial effect, show that a minimum radiation dose of 20 Gy may be adequate to eliminate the hypersecretion in acromegalic patients whereas a dose of at least 25 Gy may be required in patients with Cushing's disease and prolactinoma. (author)

Salvage gamma knife radiosurgery in the management of dysembryoplastic neuroepithelial tumors

DEFF Research Database (Denmark)

Sinclair, Georges; Martin, Heather; Shamikh, Alia

2017-01-01

BACKGROUND: Dysembryoplastic neuroepithelial tumors (DNT/DNET) are rare epileptogenic tumors. Microsurgery remains the best treatment option, although case reports exist on the use of gamma knife radiosurgery (GKRS) in selected cases. We investigated the long-term outcome of GKRS-treated DNTs...

Imaging of rare radiation injuries after radiosurgery for brain metastases

International Nuclear Information System (INIS)

Yamanaka, Kazuhiro; Yoshimura, Masaki; Iwai, Yoshiyasu

2011-01-01

Gamma knife radiosurgery (GKS) is generally an effective and safe treatment for brain metastases. We report 3 rare complicated cases after GKS due to radiation injury including image findings. Case 1: A 58-year-old man received whole brain radiation therapy for right occipital brain metastasis from lung cancer. However, local recurrence was noted and GKS was carried out 5 months later (size 28 mm, marginal dose 23 Gy (50% isodose)). Four years later, a cyst appeared and the patient developed apraxia and visual disturbance. Surgery was performed and the histopathology showed necrosis. Case 2: A 51-year-old woman received GKS for 4 brain metastases from breast cancer. The right occipital lobe lesion was treated with marginal dose of 18 Gy (size 24 mm, 50% isodose). Thirty-one months later, she developed left homonymous hemianopsia and MR imaging and CT scan showed intracerebral hemorrhage with cyst formation. An operation was performed and the histology revealed necrosis. Case 3: A 37-year-old man received GKS for left temporal brain metastasis from lung cancer (size 14 mm, marginal dose 23 Gy (50% isodose)). Twelve months later, the lesion increased in size again, so we carried out a second GKS on the same lesion (size 15 mm, marginal dose 23 Gy (50% isodose)). Thirty-five months later, massive peritumoral edema appeared and the patient developed left oculomotor palsy. An emergency operation was performed and the histopathological diagnosis was cavernous malformation that was thought to be induced by radiosurgery. Although the incidence is low, rare complications associated with radiation therapy can also occur by radiosurgery. (author)

Spine radiosurgery for the local treatment of spine metastases: Intensity-modulated radiotherapy, image guidance, clinical aspects and future directions

International Nuclear Information System (INIS)

Moraes, Fabio Ynoe de; Neves-Junior, Wellington Furtado Pimenta; Hanna, Samir Abdallah; Carvalho, Heloisa de Andrade; Laufer, Ilya

2016-01-01

Many cancer patients will develop spinal metastases. Local control is important for preventing neurologic compromise and to relieve pain. Stereotactic body radiotherapy or spinal radiosurgery is a new radiation therapy technique for spinal metastasis that can deliver a high dose of radiation to a tumor while minimizing the radiation delivered to healthy, neighboring tissues. This treatment is based on intensity-modulated radiotherapy, image guidance and rigid immobilization. Spinal radiosurgery is an increasingly utilized treatment method that improves local control and pain relief after delivering ablative doses of radiation. Here, we present a review highlighting the use of spinal radiosurgery for the treatment of metastatic tumors of the spine. The data used in the review were collected from both published studies and ongoing trials. We found that spinal radiosurgery is safe and provides excellent tumor control (up to 94% local control) and pain relief (up to 96%), independent of histology. Extensive data regarding clinical outcomes are available; however, this information has primarily been generated from retrospective and non randomized prospective series. Currently, two randomized trials are enrolling patients to study clinical applications of fractionation schedules spinal Radiosurgery. Additionally, a phase I clinical trial is being conducted to assess the safety of concurrent stereotactic body radiotherapy and ipilimumab for spinal metastases. Clinical trials to refine clinical indications and dose fractionation are ongoing. The concomitant use of targeted agents may produce better outcomes in the future. (author)

Spine radiosurgery for the local treatment of spine metastases: Intensity-modulated radiotherapy, image guidance, clinical aspects and future directions

Energy Technology Data Exchange (ETDEWEB)

Moraes, Fabio Ynoe de; Neves-Junior, Wellington Furtado Pimenta; Hanna, Samir Abdallah; Carvalho, Heloisa de Andrade [Hospital Sirio-Libanes, Sao Paulo, SP (Brazil). Departamento de Radioterapia; Taunk, Neil Kanth; Yamada, Yoshiya [Memorial Sloan Kettering Cancer Center, Department of Radiation Oncology, New York, NY (United States); Laufer, Ilya, E-mail: fymoraes@gmail.com [Memorial Sloan Kettering Cancer Center, Department of Neurosurgery, New York, NY (United States)

2016-02-15

Many cancer patients will develop spinal metastases. Local control is important for preventing neurologic compromise and to relieve pain. Stereotactic body radiotherapy or spinal radiosurgery is a new radiation therapy technique for spinal metastasis that can deliver a high dose of radiation to a tumor while minimizing the radiation delivered to healthy, neighboring tissues. This treatment is based on intensity-modulated radiotherapy, image guidance and rigid immobilization. Spinal radiosurgery is an increasingly utilized treatment method that improves local control and pain relief after delivering ablative doses of radiation. Here, we present a review highlighting the use of spinal radiosurgery for the treatment of metastatic tumors of the spine. The data used in the review were collected from both published studies and ongoing trials. We found that spinal radiosurgery is safe and provides excellent tumor control (up to 94% local control) and pain relief (up to 96%), independent of histology. Extensive data regarding clinical outcomes are available; however, this information has primarily been generated from retrospective and non randomized prospective series. Currently, two randomized trials are enrolling patients to study clinical applications of fractionation schedules spinal Radiosurgery. Additionally, a phase I clinical trial is being conducted to assess the safety of concurrent stereotactic body radiotherapy and ipilimumab for spinal metastases. Clinical trials to refine clinical indications and dose fractionation are ongoing. The concomitant use of targeted agents may produce better outcomes in the future. (author)

Shortening treatment time in robotic radiosurgery using a novel node reduction technique

Energy Technology Data Exchange (ETDEWEB)

Water, Steven van de; Hoogeman, Mischa S.; Breedveld, Sebastiaan; Heijmen, Ben J. M. [Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Groene Hilledijk 301, 3075 EA Rotterdam (Netherlands)

2011-03-15

Purpose: The fraction duration of robotic radiosurgery treatments can be reduced by generating more time-efficient treatment plans with a reduced number of node positions, beams, and monitor units (MUs). Node positions are preprogramed locations where the robot can position the focal spot of the x-ray beam. As the time needed for the robot to travel between node positions takes up a large part of the treatment time, the aim of this study was to develop and evaluate a node reduction technique in order to reduce the treatment time per fraction for robotic radiosurgery. Methods: Node reduction was integrated into the inverse planning algorithm, developed in-house for the robotic radiosurgery modality. It involved repeated inverse optimization, each iteration excluding low-contribution node positions from the planning and resampling new candidate beams from the remaining node positions. Node reduction was performed until the exclusion of a single node position caused a constraint violation, after which the shortest treatment plan was selected retrospectively. Treatment plans were generated with and without node reduction for two lung cases of different complexity, one oropharyngeal case and one prostate case. Plan quality was assessed using the number of node positions, beams and MUs, and the estimated treatment time per fraction. All treatment plans had to fulfill all clinical dose constraints. Extra constraints were added to maintain the low-dose conformality and restrict skin doses during node reduction. Results: Node reduction resulted in 12 residual node positions, on average (reduction by 77%), at the cost of an increase in the number of beams and total MUs of 28% and 9%, respectively. Overall fraction durations (excluding patient setup) were shortened by 25% (range of 18%-40%), on average. Dose distributions changed only little and dose in low-dose regions was effectively restricted by the additional constraints. Conclusions: The fraction duration of robotic

Shortening treatment time in robotic radiosurgery using a novel node reduction technique

International Nuclear Information System (INIS)

Water, Steven van de; Hoogeman, Mischa S.; Breedveld, Sebastiaan; Heijmen, Ben J. M.

2011-01-01

Purpose: The fraction duration of robotic radiosurgery treatments can be reduced by generating more time-efficient treatment plans with a reduced number of node positions, beams, and monitor units (MUs). Node positions are preprogramed locations where the robot can position the focal spot of the x-ray beam. As the time needed for the robot to travel between node positions takes up a large part of the treatment time, the aim of this study was to develop and evaluate a node reduction technique in order to reduce the treatment time per fraction for robotic radiosurgery. Methods: Node reduction was integrated into the inverse planning algorithm, developed in-house for the robotic radiosurgery modality. It involved repeated inverse optimization, each iteration excluding low-contribution node positions from the planning and resampling new candidate beams from the remaining node positions. Node reduction was performed until the exclusion of a single node position caused a constraint violation, after which the shortest treatment plan was selected retrospectively. Treatment plans were generated with and without node reduction for two lung cases of different complexity, one oropharyngeal case and one prostate case. Plan quality was assessed using the number of node positions, beams and MUs, and the estimated treatment time per fraction. All treatment plans had to fulfill all clinical dose constraints. Extra constraints were added to maintain the low-dose conformality and restrict skin doses during node reduction. Results: Node reduction resulted in 12 residual node positions, on average (reduction by 77%), at the cost of an increase in the number of beams and total MUs of 28% and 9%, respectively. Overall fraction durations (excluding patient setup) were shortened by 25% (range of 18%-40%), on average. Dose distributions changed only little and dose in low-dose regions was effectively restricted by the additional constraints. Conclusions: The fraction duration of robotic

SU-E-T-420: Failure Effects Mode Analysis for Trigeminal Neuralgia Frameless Radiosurgery

Energy Technology Data Exchange (ETDEWEB)

Howe, J [Associates In Medical Physics, Louisville, KY (United States)

2015-06-15

Purpose: Functional radiosurgery has been used successfully in the treatment of trigeminal neuralgia but presents significant challenges to ensuring the high prescription dose is delivered accurately. A review of existing practice should help direct the focus of quality improvement for this treatment regime. Method: Failure modes and effects analysis was used to identify the processes in preparing radiosurgery treatment for TN. The map was developed by a multidisciplinary team including: neurosurgeon, radiation oncology, physicist and therapist. Potential failure modes were identified for each step in the process map as well as potential causes and end effect. A risk priority number was assigned to each cause. Results: The process map identified 66 individual steps (see attached supporting document). Corrective actions were developed for areas of high risk priority number. Wrong site treatment is at higher risk for trigeminal neuralgia treatment due to the lack of site specific pathologic imaging on MR and CT – additional site specific checks were implemented to minimize the risk of wrong site treatment. Failed collision checks resulted from an insufficient collision model in the treatment planning system and a plan template was developed to address this problem. Conclusion: Failure modes and effects analysis is an effective tool for developing quality improvement in high risk radiotherapy procedures such as functional radiosurgery.

SU-E-T-420: Failure Effects Mode Analysis for Trigeminal Neuralgia Frameless Radiosurgery

International Nuclear Information System (INIS)

Howe, J

2015-01-01

Purpose: Functional radiosurgery has been used successfully in the treatment of trigeminal neuralgia but presents significant challenges to ensuring the high prescription dose is delivered accurately. A review of existing practice should help direct the focus of quality improvement for this treatment regime. Method: Failure modes and effects analysis was used to identify the processes in preparing radiosurgery treatment for TN. The map was developed by a multidisciplinary team including: neurosurgeon, radiation oncology, physicist and therapist. Potential failure modes were identified for each step in the process map as well as potential causes and end effect. A risk priority number was assigned to each cause. Results: The process map identified 66 individual steps (see attached supporting document). Corrective actions were developed for areas of high risk priority number. Wrong site treatment is at higher risk for trigeminal neuralgia treatment due to the lack of site specific pathologic imaging on MR and CT – additional site specific checks were implemented to minimize the risk of wrong site treatment. Failed collision checks resulted from an insufficient collision model in the treatment planning system and a plan template was developed to address this problem. Conclusion: Failure modes and effects analysis is an effective tool for developing quality improvement in high risk radiotherapy procedures such as functional radiosurgery

Radiocromic film, TLD, OSL and 'Paracas Phantom' by dosimetric intercomparation in stereotactic radiosurgery

International Nuclear Information System (INIS)

Paucar Jauregui, R.; Condori Marcos, P.; Vidarte Garcia, F.

2008-01-01

Full text: In Peru, one deals to patients with arteriovenous malformations or cerebral tumors by means of stereotactic radiosurgery, using fine photon beams of high energy of 6 MeV, generated by a linear accelerator Varian 2100 Clinac CD of the Complejo Hospitalario San Pablo in Lima, Peru. In this work we describes the 'Dosimetric Intercomparation System of the Quality Assurance Program in Stereotactic Radiosurgery of the Complejo Hospitalario San Pablo (DIS)'. The DIS allows to guarantee application of the doses with high accuracy. It shows the good performance of the Local DIS's components: dosimetry of radiocromics films, dosimetry termoluminiscent (TLD), dosimetry of optically stimulated luminescence (OSL) and an anthropomorphic phantom of head constructed locally, denominated 'Paracas Phantom'. Also, in the International DIS practiced with The University of Texas Md Anderson Cancer Center, stands out results within the ranges: a) Dose to the center of the target (RDS/Institution): 0,95-1,05; b) Treated volumen (Measured/Institution): 0,75 - 1,05; c) Ratio of measure treated volume to target volume: 1,00 - 2,00; and d) Minimum dose to target (Minimum dose/Prescription dose): >0,90. It concludes that the DIS is important for the good decision making on the radiological safety of the patients dealt with stereotactic radiosurgery. (author)

Grading of vestibular schwannomas and corresponding tumor volumes: ramifications for radiosurgery.

Science.gov (United States)

Mindermann, T; Schlegel, I

2013-01-01

Patients with vestibular schwannomas (VS) are either assigned to watchful waiting, microsurgical resection, or radiosurgery. Decision making on how to proceed is based on parameters such as age, tumor growth, loss of hearing, and the tumor's Koos grading. In order to correlate Koos grading with tumor volume, patient records of 235 patients with VS who underwent Gamma Knife radiosurgery (GKRS) were retrospectively reviewed. From 1994 to 2009, 235 consecutive patients underwent GKRS for sporadic VS at the Zurich Gamma Knife Center. Median follow up was 62.8 ± 33.0 months. Of the 235 tumors, 32 (13.6 %) were graded Koos I with a volume of 0.25 ± 0.3 cc; 71 (30.2 %) were graded Koos II with a volume of 0.57 ± 0.54 cc; 70 (29.8 %) were graded Koos III with a volume of 1.82 ± 1.88 cc; and 62 (26.4 %) were graded Koos IV with a volume of 4.17 ± 2.75 cc. Tumor progression was defined as a volume increase > 20 % at 2 years or later following GKRS. Overall tumor progression occurred in 21/235 (8.9 %) patients at 3.4 ± 0.9 years. Tumor progression did not differ statistically significantly in the various Koos grades: 1/32 (3.1 %) patients with VS Koos Grade I, 7/71 (9.8 %) patients with VS Koos Grade II, 6/70 (8.6 %) patients with VS Koos Grade III, and 7/62 (11.3 %) patients with VS Koos Grade IV. To our knowledge, this is the first work correlating the various Koos grades of VS to their respective tumor volumes. In our patients, tumor volumes of VS Koos Grade IV were limited because all of our patients were eligible for radiosurgery. In our series, the outcome following GKRS for patients with VS Koos Grade IV tumors did not differ from patients with VS Koos Grades I-III. We therefore suggest to limit Koos Grade IV VS to tumor volumes 6 cc that may not be eligible for radiosurgery.

Comparison of CO(2) laser and 4.0 MHz radiosurgery for making incisions in the skin and muscles of green iguanas (Iguana iguana).

Science.gov (United States)

Hernández-Divers, S J; Stahl, S J; Rakich, P M; Blas-Machado, U

2009-01-03

Four green iguanas scheduled for euthanasia were used to compare the extent of collateral tissue damage associated with CO(2) laser and 4.0 MHz radiosurgery. The iguanas were anaesthetised and a series of three skin and three muscle incisions was made by 4.0 MHz radiosurgery (0.18 mm wire electrode, 25 W, cut mode) and CO(2) laser (0.3 mm ceramic tip, 15 W focused beam super-pulse mode), and three incisions were made with a scalpel blade as controls. Following euthanasia, a total of 60 skin and 36 muscle sections were evaluated histologically. Radiosurgery and the laser both produced bloodless incisions, but radiosurgery caused significantly less collateral tissue damage in the skin (307 [97] v 386 [108] microm) and the muscle (18 [7] v 91 [15] microm).

Stereotactic radiosurgery may contribute to overall survival for patients with recurrent head and neck carcinoma

International Nuclear Information System (INIS)

Kawaguchi, Koji; Sato, Kengo; Horie, Akihisa; Iketani, Susumu; Yamada, Hiroyuki; Nakatani, Yasunori; Sato, Junichi; Hamada, Yoshiki

2010-01-01

The aim of this study is to examine the effect of stereotactic radiosurgery (SRS) in the treatment of advanced, recurrent lesions for head and neck carcinoma both with and without lymph node involvement. Between April 2006 and July 2007, 22 patients (mean age 67 years) with advanced, recurrent head and neck carcinoma were treated with stereotactic radiosurgery. All of the patients except one had biopsy confirmed disease prior to stereotactic radiosurgery. Patients included 3 rT2, 8 rT3, and 9 rT4; 8 of the patients had lymph node metastases. Marginal SRS doses were 20-42 Gy delivered in two to five fractions. Starting one month after SRS, all patients received S-1 oral chemotherapy for one year. At an overall median follow-up of 24 months (range, 4-39 months), for the 14 locally recurrent patients without lymph node metastases, 9 patients (64.3%) had a complete response (CR), 1 patient (7.1%) had a partial response (PR), 1 patient (7.1%) had stable disease (SD), and 3 patients (21.4%) had progressive disease (PD). For the 8 patients with lymph node metastases, 1 patient with a single retropharyngeal (12.5%) had CR; the remaining 7 patients (87.5%) all progressed. Nine patients have died from their cancer. The overall actuarial 2-year survival for the patients with and without lymph node metastases is 12.5% and 78.6%, respectively. These results show the benefit of stereotactic radiosurgery salvage treatment for advanced, recurrent lesions, without lymph node metastases in previously irradiated head and neck cancer

The value of image coregistration during stereotactic radiosurgery.

Science.gov (United States)

Koga, T; Maruyama, K; Igaki, H; Tago, M; Saito, N

2009-05-01

Coregistration of any neuroimaging studies into treatment planning for stereotactic radiosurgery became easily applicable using the Leksell Gamma Knife 4C, a new model of gamma knife. The authors investigated the advantage of this image processing. Since installation of the Leksell Gamma Knife 4C at the authors' institute, 180 sessions of radiosurgery were performed. Before completion of planning, coregistration of frameless images of other modalities or previous images was considered to refine planning. Treatment parameters were compared for planning before and after refinement by use of coregistered images. Coregistered computed tomography clarified the anatomical structures indistinct on magnetic resonance imaging. Positron emission tomography visualized lesions disclosing metabolically high activity. Coregistration of prior imaging distinguished progressing lesions from stable ones. Diffusion-tensor tractography was integrated for lesions adjacent to the corticospinal tract or the optic radiation. After refinement of planning in 36 sessions, excess treated volume decreased (p = 0.0062) and Paddick conformity index improved (p < 0.001). Maximal dose to the white matter tracts was decreased (p < 0.001). Image coregistration provided direct information on anatomy, metabolic activity, chronological changes, and adjacent critical structures. This gathered information was sufficiently informative during treatment planning to supplement ambiguous information on stereotactic images, and was useful especially in reducing irradiation to surrounding normal structures.

TH-A-BRC-01: AAPM TG-135U1 QA for Robotic Radiosurgery

International Nuclear Information System (INIS)

Dieterich, S.

2016-01-01

AAPM TG-135U1 QA for Robotic Radiosurgery - Sonja Dieterich Since the publication of AAPM TG-135 in 2011, the technology of robotic radiosurgery has rapidly developed. AAPM TG-135U1 will provide recommendations on the clinical practice for using the IRIS collimator, fiducial-less real-time motion tracking, and Monte Carlo based treatment planning. In addition, it will summarize currently available literature about uncertainties. Learning Objectives: Understand the progression of technology since the first TG publication Learn which new QA procedures should be implemented for new technologies Be familiar with updates to clinical practice guidelines AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance - Steven Goetsch Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocol modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers. Conclusion: The full report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and outline

TH-A-BRC-01: AAPM TG-135U1 QA for Robotic Radiosurgery

Energy Technology Data Exchange (ETDEWEB)

Dieterich, S. [UC Davis Medical Center (United States)

2016-06-15

AAPM TG-135U1 QA for Robotic Radiosurgery - Sonja Dieterich Since the publication of AAPM TG-135 in 2011, the technology of robotic radiosurgery has rapidly developed. AAPM TG-135U1 will provide recommendations on the clinical practice for using the IRIS collimator, fiducial-less real-time motion tracking, and Monte Carlo based treatment planning. In addition, it will summarize currently available literature about uncertainties. Learning Objectives: Understand the progression of technology since the first TG publication Learn which new QA procedures should be implemented for new technologies Be familiar with updates to clinical practice guidelines AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance - Steven Goetsch Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocol modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers. Conclusion: The full report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and outline

Hearing preservation after low-dose gamma knife radiosurgery of vestibular schwannomas

International Nuclear Information System (INIS)

Horiba, Ayako; Hayashi, Motohiro; Chernov, Mikhail; Kawamata, Takakazu; Okada, Yoshikazu

2016-01-01

The objective of the retrospective study was to evaluate the factors associated with hearing preservation after low-dose Gamma Knife radiosurgery (GKS) of vestibular schwannomas performed according to the modern standards. From January 2005 to September 2010, 141 consecutive patients underwent such treatment in Tokyo Women's Medical University. Mean marginal dose was 11.9 Gy (range, 11-12 Gy). The doses for the brain stem, cranial nerves (V, VII, and VHIII), and cochlea were kept below 14 Gy, 12 Gy, and 4 Gy, respectively. Out of the total cohort, 102 cases with at least 24 months follow-up were analyzed. Within the median follow-up of 56 months (range, 24-99 months) the crude tumor growth control was 92% (94 cases), whereas its actuarial rate at 5 years was 93%. Out of 49 patients with serviceable hearing on the side of the tumor before GKS, 28 (57%) demonstrated its preservation at the time of the last follow-up. No one evaluated factor, namely Gardner-Robertson hearing class before irradiation, Koos tumor stage, extension of the intrameatal part of the neoplasm up to fundus, nerve of tumor origin, presence of cystic changes in the neoplasm, and cochlea dose demonstrated statistically significant association with preservation of the serviceable hearing after radiosurgery. In conclusion, GKS of vestibular schwannomas performed according to the modern standards of treatment permits to preserve serviceable hearing on the side of the tumor in more than half of the patients. The actual causes of hearing deterioration after radiosurgery remain unclear. (author)

Quality control of radiosurgery: dosimetry with micro camera in spherical mannequin

International Nuclear Information System (INIS)

Casado Villalon, F. J.; Navarro Guirado, F.; Garci Pareja, S.; Benitez Villegas, E. M.; Galan Montenegro, P.; Moreno Saiz, C.

2013-01-01

The dosimetry of small field is part of quality control in the treatment of cranial radiosurgery. In this work the results of absorbed dose in the isocenter, Planner, with those obtained from are compared experimentally with a micro-camera into an spherical mannequin. (Author)

Gamma Knife radiosurgery for glomus jugulare tumors: a single-center series of 75 cases.

Science.gov (United States)

Ibrahim, Ramez; Ammori, Mohannad B; Yianni, John; Grainger, Alison; Rowe, Jeremy; Radatz, Matthias

2017-05-01

OBJECTIVE Glomus jugulare tumors are rare indolent tumors that frequently involve the lower cranial nerves (CNs). Complete resection can be difficult and associated with lower CN injury. Gamma Knife radiosurgery (GKRS) has established its role as a noninvasive alternative treatment option for these often formidable lesions. The authors aimed to review their experience at the National Centre for Stereotactic Radiosurgery, Sheffield, United Kingdom, specifically the long-term tumor control rate and complications of GKRS for these lesions. METHODS Clinical and radiological data were retrospectively reviewed for patients treated between March 1994 and December 2010. Data were available for 75 patients harboring 76 tumors. The tumors in 3 patients were treated in 2 stages. Familial and/or hereditary history was noted in 12 patients, 2 of whom had catecholamine-secreting and/or active tumors. Gamma Knife radiosurgery was the primary treatment modality in 47 patients (63%). The median age at the time of treatment was 55 years. The median tumor volume was 7 cm 3 , and the median radiosurgical dose to the tumor margin was 18 Gy (range 12-25 Gy). The median duration of radiological follow-up was 51.5 months (range 12-230 months), and the median clinical follow-up was 38.5 months (range 6-223 months). RESULTS The overall tumor control rate was 93.4% with low CN morbidity. Improvement of preexisting deficits was noted in 15 patients (20%). A stationary clinical course and no progression of symptoms were noted in 48 patients (64%). Twelve patients (16%) had new symptoms or progression of their preexisting symptoms. The Kaplan-Meier actuarial tumor control rate was 92.2% at 5 years and 86.3% at 10 years. CONCLUSIONS Gamma Knife radiosurgery offers a risk-versus-benefit treatment option with very low CN morbidity and stable long-term results.

The lazaroid U74389G protects normal brain from stereotactic radiosurgery-induced radiation injury

International Nuclear Information System (INIS)

Buatti, John M.; Friedman, William A.; Theele, Daniel P.; Bova, Francis J.; Mendenhall, William M.

1996-01-01

Purpose: To test an established model of stereotactic radiosurgery-induced radiation injury with pretreatments of either methylprednisolone or the lazaroid U74389G. Methods and Materials: Nine cats received stereotactic radiosurgery with a linear accelerator using an animal radiosurgery device. Each received a dose of 125.0 Gy prescribed to the 84% isodose shell to the anterior limb of the right internal capsule. One animal received no pretreatment, two received citrate vehicle, three received 30 mg/kg of methylprednisolone, and three received 5 mg/kg of U74389G. After irradiation, the animals had frequent neurologic examinations, and neurologic deficits developed in all of them. Six months after the radiation treatment, the animals were anesthetized, and had gadolinium-enhanced magnetic resonance (MR) scans, followed by Evans blue dye perfusion, euthanasia, and brain fixation. Results: Magnetic resonance scans revealed a decrease in the size of the lesions from a mean volume of 0.45 ± 0.06 cm 3 in the control, vehicle-treated, and methylprednisolone-treated animals to 0.22 ± 0.14 cm 3 in the U74389G-treated group. The scans also suggested the absence of necrosis and ventricular dilatation in the lazaroid-treated group. Gross pathology revealed that lesions produced in the untreated, vehicle-treated, and methylprednisolone-treated cats were similar and were characterized by a peripheral zone of Evans blue dye staining with a central zone of a mature coagulative necrosis and focal hemorrhage. However, in the U74389G-treated animals, the lesions were found to have an area of Evans blue dye staining, but lacked discrete areas of necrosis and hemorrhage. Conclusion: These results suggest that the lazaroid U74389G protects the normal brain from radiation injury produced by stereotactic radiosurgery

Concomitant GRID boost for Gamma Knife radiosurgery

International Nuclear Information System (INIS)

Ma Lijun; Kwok, Young; Chin, Lawrence S.; Simard, J. Marc; Regine, William F.

2005-01-01

We developed an integrated GRID boost technique for Gamma Knife radiosurgery. The technique generates an array of high dose spots within the target volume via a grid of 4-mm shots. These high dose areas were placed over a conventional Gamma Knife plan where a peripheral dose covers the full target volume. The beam weights of the 4-mm shots were optimized iteratively to maximize the integral dose inside the target volume. To investigate the target volume coverage and the dose to the adjacent normal brain tissue for the technique, we compared the GRID boosted treatment plans with conventional Gamma Knife treatment plans using physical and biological indices such as dose-volume histogram (DVH), DVH-derived indices, equivalent uniform dose (EUD), tumor control probabilities (TCP), and normal tissue complication probabilities (NTCP). We found significant increase in the target volume indices such as mean dose (5%-34%; average 14%), TCP (4%-45%; average 21%), and EUD (2%-22%; average 11%) for the GRID boost technique. No significant change in the peripheral dose coverage for the target volume was found per RTOG protocol. In addition, the EUD and the NTCP for the normal brain adjacent to the target (i.e., the near region) were decreased for the GRID boost technique. In conclusion, we demonstrated a new technique for Gamma Knife radiosurgery that can escalate the dose to the target while sparing the adjacent normal brain tissue

Clinical-radiological evaluation of sequelae of stereotactic radiosurgery for intracranial arteriovenous malformations

International Nuclear Information System (INIS)

Levy, R.P.; Fabrikant, J.I.; Frankel, K.A.; Phillips, M.H.; Steinberg, G.K.; Marks, M.P.; DeLaPaz, R.L.; Chuang, F.Y.S.

1989-12-01

Stereotactic heavy-charged-particle Bragg peak radiosurgery has been used to treat 322 patients with surgically-inaccessible intracranial vascular malformations. (The clinical results of this method for the treatment of angiographically demonstrable arteriovenous malformations (AVMs) and angiographically occult vascular malformations (AOVMs) of the brain are described in separate reports of this symposium). The great majority of patients have had an uneventful post-treatment course with satisfactory health outcomes. However, several categories of delayed sequelae of stereotactic radiosurgery have been identified, involving the vascular structures essential for the integrity of the brain tissue and the brain parenchyma directly. These categories reflect both reaction to injury and to alterations in regional hemodynamic status, and include vasogenic edema, occlusion of functional vasculature, radiation necrosis, and local or remote effects on cerebral arterial aneurysms. 10 refs., 7 figs., 1 tab

Clinical-radiological evaluation of sequelae of stereotactic radiosurgery for intracranial arteriovenous malformations

Energy Technology Data Exchange (ETDEWEB)

Levy, R.P.; Fabrikant, J.I.; Frankel, K.A.; Phillips, M.H.; Steinberg, G.K.; Marks, M.P.; DeLaPaz, R.L.; Chuang, F.Y.S.

1989-12-01

Stereotactic heavy-charged-particle Bragg peak radiosurgery has been used to treat 322 patients with surgically-inaccessible intracranial vascular malformations. (The clinical results of this method for the treatment of angiographically demonstrable arteriovenous malformations (AVMs) and angiographically occult vascular malformations (AOVMs) of the brain are described in separate reports of this symposium). The great majority of patients have had an uneventful post-treatment course with satisfactory health outcomes. However, several categories of delayed sequelae of stereotactic radiosurgery have been identified, involving the vascular structures essential for the integrity of the brain tissue and the brain parenchyma directly. These categories reflect both reaction to injury and to alterations in regional hemodynamic status, and include vasogenic edema, occlusion of functional vasculature, radiation necrosis, and local or remote effects on cerebral arterial aneurysms. 10 refs., 7 figs., 1 tab.

Stereotactic radiotherapy and radiosurgery in pediatric patients: analysis of indications and outcome

DEFF Research Database (Denmark)

Mirza, Bilal; Mønsted, Anne; Jensen, Josephine Harding

2010-01-01

We describe indications, outcomes, and risk profiles of fractionated stereotactic radiotherapy (SRT) and single fraction "radiosurgery" (SRS) in pediatric patients compared to the adult population and evaluate the causal role of SRS and SRT in inducing new neurological complications....

The role of stereotactic radiosurgery in the treatment of malignant skull base tumors

International Nuclear Information System (INIS)

Miller, Robert C.; Foote, Robert L.; Coffey, Robert J.; Gorman, Deborah A.; Earle, John D.; Schomberg, Paula J.; Kline, Robert W.

1997-01-01

Purpose: To determine the efficacy and toxicity of stereotactic radiosurgery in the treatment of malignant skull base tumors. Methods and Materials: Thirty-two patients with 35 newly diagnosed or recurrent malignant skull base tumors ≤33.5 cm 3 were treated using the Leksell Gamma unit. Tumor histologies included: adenoid cystic carcinoma, basal cell carcinoma, chondrosarcoma, chordoma, nasopharyngeal carcinoma, osteogenic sarcoma, and squamous cell carcinoma. Results: After a median follow-up of 2.3 years, 83% ± 15% (±95% confidence interval) of patients experienced a symptomatic response to treatment. Local control at the skull base was 95 ± 9% at 2 years and 78 ± 23% at 3 years. Local-regional control above the clavicles was 75 ± 15% at 1 year and 51 ± 20% at 2 years. Overall and cause specific survival were identical, 82 ± 13% at 1 year, 76 ± 14% at 2 years, and 72 ± 16% at 3 years. One patient developed a radiation-induced optic neuropathy 12 months after radiosurgery. Conclusion: Stereotactic radiosurgery using the Leksell Gamma Unit can provide durable tumor control and symptomatic relief with acceptable toxicity in the majority of patients with malignant tumors 4 cm or less in size involving the skull base. Further evaluation of more patients with longer follow-up is warranted

Stereotactic radiosurgery using the gamma knife for acoustic neuromas

International Nuclear Information System (INIS)

Foote, Robert L.; Coffey, Robert J.; Swanson, Jerry W.; Harner, Stephen G.; Beatty, Charles W.; Kline, Robert W.; Stevens, Lorna N.; Hu, Theresa C.

1995-01-01

Purpose: To assess the efficacy and toxicity of stereotactic radiosurgery using the gamma knife for acoustic neuromas. Methods and Materials: Between January 1990 and January 1993, 36 patients with acoustic neuromas were treated with stereotactic radiosurgery using the gamma knife. The median maximum tumor diameter was 21 mm (range: 6-32 mm). Tumor volumes encompassed within the prescribed isodose line varied from 266 to 8,667 mm 3 (median: 3,135 mm 3 ). Tumors ≤ 20 mm in maximum diameter received a dose of 20 Gy to the margin, tumors between 21 and 30 mm received 18 Gy, and tumors > 30 mm received 16 Gy. The dose was prescribed to the 50% isodose line in 31 patients and to the 45%, 55%, 60%, 70%, and 80% isodose line in one patient each. The median number of isocenters per tumor was 5 (range: 1-12). Results: At a median follow-up of 16 months (range: 2.5-36 months), all patients were alive. Thirty-five patients had follow-up imaging studies. Nine tumors (26%) were smaller, and 26 tumors (74%) were unchanged. No tumor had progressed. The 1- and 2-year actuarial incidences of facial neuropathy were 52.2% and 66.5%, respectively. The 1- and 2-year actuarial incidences of trigeminal neuropathy were 33.7% and 58.9%, respectively. The 1- and 2-year actuarial incidence of facial or trigeminal neuropathy (or both) was 60.8% and 81.7%, respectively. Multivariate analysis revealed that the following were associated with the time of onset or worsening of facial weakness or trigeminal neuropathy: (a) patients five isocenters. The 1- and 2-year actuarial rates of preservation of useful hearing (Gardner-Robertson class I or II) were 100% and 41.7% ± 17.3, respectively. Conclusion: Stereotactic radiosurgery using the gamma knife provides short-term control of acoustic neuromas when a dose of 16 to 20 Gy to the tumor margin is used. Preservation of useful hearing can be accomplished in a significant proportion of patients

Feasibility of four-dimensional conformal planning for robotic radiosurgery

International Nuclear Information System (INIS)

Schlaefer, A.; Fisseler, J.; Dieterich, S.; Shiomi, H.; Cleary, K.; Schweikard, A.

2005-01-01

Organ motion can have a severe impact on the dose delivered by radiation therapy, and different procedures have been developed to address its effects. Conventional techniques include breath hold methods and gating. A different approach is the compensation for target motion by moving the treatment beams synchronously. Practical results have been reported for robot based radiosurgery, where a linear accelerator mounted on a robotic arm delivers the dose. However, not all organs move in the same way, which results in a relative motion of the beams with respect to the body and the tissues in the proximity of the tumor. This relative motion can severely effect the dose delivered to critical structures. We propose a method to incorporate motion in the treatment planning for robotic radiosurgery to avoid potential overdosing of organs surrounding the target. The method takes into account the motion of all considered volumes, which is discretized for dose calculations. Similarly, the beam motion is taken into account and the aggregated dose coefficient over all discrete steps is used for planning. We simulated the treatment of a moving target with three different planning methods. First, we computed beam weights based on a 3D planning situation and simulated treatment with organ motion and the beams moving synchronously to the target. Second, beam weights were computed by the 4D planning method incorporating the organ and beam motion and treatment was simulated for beams moving synchronously to the target. Third, the beam weights were determined by the 4D planning method with the beams fixed during planning and simulation. For comparison we also give results for the 3D treatment plan if there was no organ motion and when the plan is delivered by fixed beams in the presence of organ motion. The results indicate that the new 4D method is preferable and can further improve the overall conformality of motion compensated robotic radiosurgery

Dosimetric evaluation of proton stereotactic radiosurgery

International Nuclear Information System (INIS)

Min, Byung Jun; Shin, Dong Ho; Yoo, Seung Hoon; Jeong, Hojin; Lee, Se Byeong

2011-01-01

Surgical excision, conventional external radiotherapy, and chemotherapy could prolong survival in patients with small intracranial tumors. However, surgical excision for meningiomas located in the region of the base of skull or re-resection is often difficult. Moreover, treatment is needed for patients with recurrent tumors or postoperative residual tumors. Conventional external radiotherapy is popular and has significantly increased for treating brain tumors. Stereotactic radiosurgery is an effective alternative treatment technique to microsurgical resection such as benign brain tumor or vestibular Schwannomas. In general, the dose to OAR of 3D conformal plan is lower than that of conformal arc and dynamic conformal arc plans. However, any of OARs was not reached to tolerance dose. Although mean dose of the healthy brain tissue for 3D conformal plan was slightly higher than that of arc plans, the doses of the healthy brain tissue at V10 and V20 were significantly low for dynamic conformal arc plan. The dosimetric differences were the greatest at lower doses. In contrast, 3D conformal plan was better spare at higher doses. In this study, a dosimetric evaluation of proton stereotactic radiosurgery for brain lesion tumors was using fixed and arc beams. A brass block fitted to the PTV structure was modeled for dynamic conformal collimator. Although all treatment plans offer a very good coverage of the PTV, we found that proton arc plans had significantly better conformity to the PTV than static 3D conformal plan. The V20 dose of normal brain for dynamic conformal arc therapy is dramatically reduced compare to those for other therapy techniques.

Neuropsychologic changes in patients with arterio-venous malformation (AVM) after radiosurgery

International Nuclear Information System (INIS)

Steinvorth, S.; Wenz, F.; Wildermuth, S.; Fuss, M.; Debus, J.; Lohr, F.; Wannenmacher, M.

1997-01-01

Purpose/Objective: Cerebral AVM are inborn malformations which may become symptomatic in young adult patients by hemorrhage, seizures or steal syndromes. Depending on size, location and drainage, there is a risk for rupture with potentially devastating consequences. Treatment options include neurosurgery, embolization or radiosurgery. The radiosensitivity of normal brain tissue is the main limitation for radiotherapy of CNS tumors. Improved treatment planning and irradiation techniques, however, minimize the dose to unaffected brain tissue. The purpose of this study was to investigate the neuropsychological effects of radiosurgical treatment in patients with cerebral AVM. Materials and Methods: Forty-four patients with cerebral arterio-venous malformations were included into the study. Patients with hemiparesis, aphasia or hemianopia were excluded from testing. The patients were examined the day before (n=44), acutely after radiosurgery (n=23) and during the regular follow-up (subacute phase n=21, chronic phase n=12). Radiosurgery was performed using a modified linear accelerator and either rotations of 9 non-coplanar arcs or 15 individually collimated, isocentric, non-coplanar fields. Doses of 15 - 22 Gy (median 20 Gy) were prescribed to the 80% isodose (minimum dose to the target volume). The dose to the total brain was calculated as 0.5 to 2 Gy depending on dose, location and size of the target volume. The neuropsychological testing was done using a computer assisted testing facility allowing standardized testing conditions. The extensive testing battery included assessment of general intelligence (shortened version Wechsler Adult Intelligence Scale), attention (Digit Symbol Test (DST), D2 test (D2), a letter cancellation test, a modified Trail Making Test A (ZVT), and the WDG measuring the reaction time in a complex signal-reaction-situation) and memory (Benton Visual Retention Test (BVRT), Rey Auditory Verbal Learning Test (RAVLT), Cube test). Testing during

Implementation of a lung radiosurgery program: technical considerations and quality assurance in an Australian institution

International Nuclear Information System (INIS)

Siva, Shankar; MacManus, Michael; Ball, David; Chesson, Brent; Aarons, Yolanda; Clements, Natalie; Kron, Tomas

2012-01-01

The Peter MacCallum Cancer Centre has established a stereotactic lung radiosurgery program for the treatment of isolated lung metastases. The aim of this study was to critically assess the technical feasibility of performing stereotactic lung radiosurgery in an Australian institution. A single 26-Gy fraction of radiotherapy was delivered to patients with positron emission tomography (PET) staged solitary lung metastases. Motion management was addressed using four-dimensional computed tomographic simulation, and cone beam CT (CBCT) online soft-tissue matching. Treatments were with multiple coplanar and non-coplanar asymmetric beams. Patients were immobilised in a dedicated stereotactic body cradle. Quality assurance (QA) of treatment plans with both ion chamber and film measurements was performed accounting for patient-specific respiratory motion. Between February 2010 and February 2011, nine patients received stereotactic lung radiosurgery. One grade 1 toxicity and one grade 2 toxicity were recorded after treatment. The mean planning target volume was 22.6 cc. A median of eight beams were delivered per treatment plan (range 7–10) with a median of two non-coplanar beams (range 0–6). At treatment plan QA, the difference between planned and delivered dose was ≤1.76% in all static and dynamic ion chamber recordings. A mid-treatment CBCT was performed at a median time of 21 min, with the mean displacement discrepancy from initial set-up being 0.4 mm (range 0–2 mm). Stereotactic radiosurgery to the lung was both feasible and tolerable at our institution. Intrafractional immobilisation within 2 mm was reproducible. Excellent concordance between planned and delivered treatments was achieved in the phantom QA.

The role of radiosurgery in the management of chordoma and chondrosarcoma of the cranial base

International Nuclear Information System (INIS)

Kondziolka, D.; Lunsford, L.D.; Flickinger, J.C.

1991-01-01

Despite conventional multimodality treatment (surgery and fractionated radiation therapy), recurrence and clinical progression of cranial base chordomas and chondrosarcomas are common. The malignant behavior of these tumors is a result of their critical location, locally aggressive nature, and high recurrence rate. To explore the role of radiosurgery in the treatment of these skull base neoplasms, we assessed its use in four patients with chordoma and two with chondrosarcoma. In five of the patients, radiosurgery was used as adjuvant therapy for residual or recurrent tumors after surgical debulking, and in one patient with a chordoma, it was the primary treatment. No patient received fractionated external beam radiotherapy. All tumors were less than 30 mm in diameter and were treated with 20 Gy to the tumor margin. Skull base computed tomography and magnetic resonance images were essential to define the anatomic relationships between tumor and adjacent basal structures. During follow-up (mean, 22 mo; range, 8-36 mo), the authors found no progression of the treated tumor volume in any patient. Neurological deficits before treatment improved in three patients; the other three patients remained in stable neurological condition. Serial follow-up imaging studies demonstrated that two patients showed reduction in tumor size and four patients had no tumor growth. In one patient, a metastatic parietal lobe chondrosarcoma developed and was treated by microsurgery. Another patient showed tumor progression outside of the radiosurgical treatment volume. The authors results attest to the value of stereotactic radiosurgery as an adjuvant or primary treatment for selected patients with chordoma or chondrosarcoma and demonstrate its potential advantages over standard fractionated irradiation. Analysis of the long-term clinical and imaging effects after radiosurgery is warranted

Gamma knife radiosurgery for typical trigeminal neuralgia: An institutional review of 108 patients

Science.gov (United States)

Elaimy, Ameer L.; Lamm, Andrew F.; Demakas, John J.; Mackay, Alexander R.; Lamoreaux, Wayne T.; Fairbanks, Robert K.; Pfeffer, Robert D.; Cooke, Barton S.; Peressini, Benjamin J.; Lee, Christopher M.

2013-01-01

Background: In this study, we present the previously unreported pain relief outcomes of 108 patients treated at Gamma Knife of Spokane for typical trigeminal neuralgia (TN) between 2002 and 2011. Methods: Pain relief outcomes were measured using the Barrow Neurological Institute (BNI) pain intensity scale. In addition, the effects gender, age at treatment, pain laterality, previous surgical treatment, repeat Gamma Knife radiosurgery (GKRS), and maximum radiosurgery dose have on patient pain relief outcomes were retrospectively analyzed. Statistical analysis was performed using Andersen 95% confidence intervals, approximate confidence intervals for log hazard ratios, and multivariate Cox proportional hazard models. Results: All 108 patients included in this study were grouped into BNI class IV or V prior to GKRS. The median clinical follow-up time was determined to be 15 months. Following the first GKRS procedure, 71% of patients were grouped into BNI class I-IIIb (I = 31%; II = 3%; IIIa = 19%; IIIb = 18%) and the median duration of pain relief for those patients was determined to be 11.8 months. New facial numbness was reported in 19% of patients and new facial paresthesias were reported in 7% of patients after the first GKRS procedure. A total of 19 repeat procedures were performed on the 108 patients included in this study. Following the second GKRS procedure, 73% of patients were grouped into BNI class I-IIIb (I = 44%; II = 6%; IIIa = 17%, IIIb = 6%) and the median duration of pain relief for those patients was determined to be 4.9 months. For repeat procedures, new facial numbness was reported in 22% of patients and new facial paresthesias were reported in 6% of patients. Conclusions: GKRS is a safe and effective management approach for patients diagnosed with typical TN. However, further studies and supporting research is needed on the effects previous surgical treatment, number of radiosurgery procedures, and maximum radiosurgery dose have on GKRS clinical

Risk factors for neurological complications after acoustic neurinoma radiosurgery: refinement from further experiences

International Nuclear Information System (INIS)

Ito, Ken; Shin, Masahiro; Matsuzaki, Masaki; Sugasawa, Keiko; Sasaki, Tomio

2000-01-01

Purpose: Further actuarial analyses of neurological complications were performed on a larger population treated by stereotactic radiosurgery at our institution, to establish the optimal treatment parameters. Methods and Materials: Between June 1990 and September 1998, 138 patients with acoustic neurinomas underwent stereotactic radiosurgery at Tokyo University Hospital. Of these, 125 patients who received medical follow-up for 6 months or more entered the present study. Patient ages ranged from 13 to 77 years (median, 53 years). Average tumor diameter ranged from 6.7 to 25.4 mm (mean, 13.9 mm). Maximum tumor doses ranged from 20 to 40 Gy (mean, 29.8 Gy) and peripheral doses from 12 to 25 Gy (mean, 15.4 Gy). One to 12 isocenters were used (median, 4). Follow-up period ranged from 6 to 104 months (median, 37 months). The potential risk factors for neurological complications were analyzed by two univariate and one multivariate actuarial analyses. Neurological complications examined include hearing loss, facial palsy, and trigeminal nerve dysfunction. Variables included in the analyses were four demographic variables, two variables concerning tumor dimensions, and four variables concerning treatment parameters. A variable with significant p values (p < 0.05) on all three actuarial analyses was considered a risk factor. Results: The variables that had significant correlation to increasing the risk for each neurological complication were: Neurofibromatosis Type 2 (NF2) for both total hearing loss and pure tone threshold (PTA) elevation; history of prior surgical resection, tumor size, and the peripheral tumor dose for facial palsy; and the peripheral tumor dose and gender (being female) for trigeminal neuropathy. In facial palsies caused by radiosurgery, discrepancy between the course of palsy and electrophysiological responses was noted. Conclusion: Risk factors for neurological complications seem to have been almost established, without large differences between

Solid craniopharyngiomas treated by stereotactic radiosurgery

International Nuclear Information System (INIS)

Backlund, E.-O.

1979-01-01

The radiological changes of solid craniopharyngiomas treated by stereotactic radiosurgery have been followed. Nine cases are considered, the patients having received gamma radiation treatment with a dose distribution permitting no part of the tumour to receive doses less than 2-3 Gy. Target doses were 20 to 50 Gy. Tumour shrinkage was registered and no complications which could be attributed with certainty to the irradiation were encountered. The results did not allow an optimal single dose to be determined with accuracy but vaguely indicated that lower doses than those used are sufficient for desired effect on the tumour without jeopardizing its surroundings. (Auth./C.F.)

Spinal Cord Tolerance to Reirradiation With Single-Fraction Radiosurgery: A Swine Model

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Medin, Paul M., E-mail: Paul.medin@utsouthwestern.edu [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Foster, Ryan D. [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Kogel, Albert J. van der [Department of Radiation Oncology, Radboud University Medical Center Nijmegen, Nijmegen (Netherlands); Sayre, James W. [Department of Biostatistics and Radiology, University of California Los Angeles, Los Angeles, California (United States); McBride, William H. [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States); Solberg, Timothy D. [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States)

2012-07-01

Purpose: This study was performed to determine swine spinal cord tolerance to single-fraction, partial-volume irradiation 1 year after receiving uniform irradiation to 30 Gy in 10 fractions. Methods and Materials: A 10-cm length of spinal cord (C3-T1) was uniformly irradiated to 30 Gy in 10 consecutive fractions and reirradiated 1 year later with a single radiosurgery dose centered within the previously irradiated segment. Radiosurgery was delivered to a cylindrical volume approximately 5 cm in length and 2 cm in diameter, which was positioned laterally to the cervical spinal cord, resulting in a dose distribution with the 90%, 50%, and 10% isodose lines traversing the ipsilateral, central, and contralateral spinal cord, respectively. Twenty-three pigs were stratified into six dose groups with mean maximum spinal cord doses of 14.9 {+-} 0.1 Gy (n = 2), 17.1 {+-} 0.3 Gy (n = 3), 19.0 {+-} 0.1 Gy (n = 5), 21.2 {+-} 0.1 Gy (n = 5), 23.4 {+-} 0.2 Gy (n = 5), and 25.4 {+-} 0.4 Gy (n = 3). The mean percentage of spinal cord volumes receiving {>=}10 Gy for the same groups were 34% {+-} 1%, 40% {+-} 1%, 46% {+-} 3%, 52% {+-} 1%, 56 {+-} 3%, and 57% {+-} 1%. The study endpoint was motor neurologic deficit as determined by a change in gait during a 1- year follow-up period. Results: A steep dose-response curve was observed with a 50% incidence of paralysis (ED{sub 50}) for the maximum point dose of 19.7 Gy (95% confidence interval, 17.4-21.4). With two exceptions, histology was unremarkable in animals with normal neurologic status, while all animals with motor deficits showed some degree of demyelination and focal white matter necrosis on the irradiated side, with relative sparing of gray matter. Histologic comparison with a companion study of de novo irradiated animals revealed that retreatment responders had more extensive tissue damage, including infarction of gray matter, only at prescription doses >20 Gy. Conclusion: Pigs receiving spinal radiosurgery 1 year after

Does increased nerve length within the treatment volume improve trigeminal neuralgia radiosurgery? a prospective double-blind, randomized study

International Nuclear Information System (INIS)

Flickinger, John C.; Pollock, Bruce E.; Kondziolka, Douglas; Phuong, Loi K.; Foote, Robert L.; Stafford, Scott L.; Lunsford, L. Dade

2001-01-01

Purpose: To test the hypothesis that increasing the nerve length within the treatment volume for trigeminal neuralgia radiosurgery would improve pain relief. Methods and Materials: Eighty-seven patients with typical trigeminal neuralgia were randomized to undergo retrogasserian gamma knife radiosurgery (75 Gy maximal dose with 4-mm diameter collimators) using either one (n=44) or two (n=43) isocenters. The median follow-up was 26 months (range 1-36). Results: Pain relief was complete in 57 patients (45 without medication and 12 with low-dose medication), partial in 15, and minimal in another 15 patients. The actuarial rate of obtaining complete pain relief (with or without medication) was 67.7%±5.1%. The pain relief was identical for one- and two-isocenter radiosurgery. Pain relapsed in 30 of 72 responding patients. Facial numbness and mild and severe paresthesias developed in 8, 5, and 1 two-isocenter patients vs. 3, 4, and 0 one-isocenter patients, respectively (p=0.23). Improved pain relief correlated with younger age (p=0.025) and fewer prior procedures (p=0.039) and complications (numbness or paresthesias) correlated with the nerve length irradiated (p=0.018). Conclusions: Increasing the treatment volume to include a longer nerve length for trigeminal neuralgia radiosurgery does not significantly improve pain relief but may increase complications

TH-A-BRC-02: AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance

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Goetsch, S. [San Diego Medical Physics (United States)

2016-06-15

AAPM TG-135U1 QA for Robotic Radiosurgery - Sonja Dieterich Since the publication of AAPM TG-135 in 2011, the technology of robotic radiosurgery has rapidly developed. AAPM TG-135U1 will provide recommendations on the clinical practice for using the IRIS collimator, fiducial-less real-time motion tracking, and Monte Carlo based treatment planning. In addition, it will summarize currently available literature about uncertainties. Learning Objectives: Understand the progression of technology since the first TG publication Learn which new QA procedures should be implemented for new technologies Be familiar with updates to clinical practice guidelines AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance - Steven Goetsch Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocol modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers. Conclusion: The full report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and outline

TH-A-BRC-02: AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance

International Nuclear Information System (INIS)

Goetsch, S.

2016-01-01

AAPM TG-135U1 QA for Robotic Radiosurgery - Sonja Dieterich Since the publication of AAPM TG-135 in 2011, the technology of robotic radiosurgery has rapidly developed. AAPM TG-135U1 will provide recommendations on the clinical practice for using the IRIS collimator, fiducial-less real-time motion tracking, and Monte Carlo based treatment planning. In addition, it will summarize currently available literature about uncertainties. Learning Objectives: Understand the progression of technology since the first TG publication Learn which new QA procedures should be implemented for new technologies Be familiar with updates to clinical practice guidelines AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance - Steven Goetsch Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocol modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers. Conclusion: The full report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and outline

Tenon hospital 3-D dosimetric methodology for radiosurgery of complex AVMs

International Nuclear Information System (INIS)

Lefkopoulos, D.; Schlienger, M.; Plazas, M.C.; Laugier, A.

1990-01-01

This paper presents the methodology of the irradiation treatment planning for the calculation of the 3-D dose distribution developed at the Tenon Hospital since four years. This dosimetric method is independent of the Linac irradiation technique, thus is can be used with any other type of radiosurgery technique. (author)

Impact on cognitive functions following gamma knife radiosurgery for cerebral arteriovenous malformations

Directory of Open Access Journals (Sweden)

A Raghunath

2016-01-01

Full Text Available Background: Radiosurgery is an alternative to surgical resection of arteriovenous malformation (AVM. Very few studies have addressed the concern of radiation injury to the brain and its attendant adverse effects on cognitive function. Materials and Methods: This prospective study included all patients who underwent gamma knife radiosurgery (GKRS at our institute for cerebral AVM between 2006 and December 2008 (n = 34. All patients underwent neuropsychological evaluation before the procedure. Neuropsychological evaluation was repeated in eighteen patients 2 years following GKRS. Clinical outcome, AVM obliteration, and factors influencing outcome were analyzed in these eighteen patients. Results: Before GKRS, more than 50% had significant impairment of neuropsychological functions compared to normal population norms. 66.6% achieved the excellent radiosurgical outcome. At 2 years follow-up, patients showed varied improvement in neuropsychological function in various categories. Pretherapeutic median value for percentage perseverative responses was 26.5 and at follow-up, it reduced to 18.2 (P = 0.039. Set shifting improved in 11 patients (61.1%, remained same in 5 patients (27.7%, and deteriorated in two patients (11.1%. Patients with a higher Spetzler-Martin grade AVM demonstrated a significantly more favorable shift in follow-up test values for set shifting function (P = 0.021. Patients with postradiation imaging changes had lesser tendency to improve in neuropsychological performance at follow-up. Conclusions: GKRS has no clinically harmful effect on cognitive and neuropsychological functioning in patients with brain AVM. On the contrary, there is an improvement in majority of patients at 2 years following radiosurgery when nidus is obliterated.

Impact on cognitive functions following gamma knife radiosurgery for cerebral arteriovenous malformations.

Science.gov (United States)

Raghunath, A; Bennett, Niranjana; Arimappamagan, Arivazhagan; Bhat, Dhananjaya I; Srinivas, Dwarakanath; Thennarasu, K; Jamuna, R; Somanna, Sampath

2016-01-01

Radiosurgery is an alternative to surgical resection of arteriovenous malformation (AVM). Very few studies have addressed the concern of radiation injury to the brain and its attendant adverse effects on cognitive function. This prospective study included all patients who underwent gamma knife radiosurgery (GKRS) at our institute for cerebral AVM between 2006 and December 2008 (n = 34). All patients underwent neuropsychological evaluation before the procedure. Neuropsychological evaluation was repeated in eighteen patients 2 years following GKRS. Clinical outcome, AVM obliteration, and factors influencing outcome were analyzed in these eighteen patients. Before GKRS, more than 50% had significant impairment of neuropsychological functions compared to normal population norms. 66.6% achieved the excellent radiosurgical outcome. At 2 years follow-up, patients showed varied improvement in neuropsychological function in various categories. Pretherapeutic median value for percentage perseverative responses was 26.5 and at follow-up, it reduced to 18.2 (P = 0.039). Set shifting improved in 11 patients (61.1%), remained same in 5 patients (27.7%), and deteriorated in two patients (11.1%). Patients with a higher Spetzler-Martin grade AVM demonstrated a significantly more favorable shift in follow-up test values for set shifting function (P = 0.021). Patients with postradiation imaging changes had lesser tendency to improve in neuropsychological performance at follow-up. GKRS has no clinically harmful effect on cognitive and neuropsychological functioning in patients with brain AVM. On the contrary, there is an improvement in majority of patients at 2 years following radiosurgery when nidus is obliterated.

Stepwise multi-criteria optimization for robotic radiosurgery

International Nuclear Information System (INIS)

Schlaefer, A.; Schweikard, A.

2008-01-01

Achieving good conformality and a steep dose gradient around the target volume remains a key aspect of radiosurgery. Clearly, this involves a trade-off between target coverage, conformality of the dose distribution, and sparing of critical structures. Yet, image guidance and robotic beam placement have extended highly conformal dose delivery to extracranial and moving targets. Therefore, the multi-criteria nature of the optimization problem becomes even more apparent, as multiple conflicting clinical goals need to be considered coordinate to obtain an optimal treatment plan. Typically, planning for robotic radiosurgery is based on constrained optimization, namely linear programming. An extension of that approach is presented, such that each of the clinical goals can be addressed separately and in any sequential order. For a set of common clinical goals the mapping to a mathematical objective and a corresponding constraint is defined. The trade-off among the clinical goals is explored by modifying the constraints and optimizing a simple objective, while retaining feasibility of the solution. Moreover, it becomes immediately obvious whether a desired goal can be achieved and where a trade-off is possible. No importance factors or predefined prioritizations of clinical goals are necessary. The presented framework forms the basis for interactive and automated planning procedures. It is demonstrated for a sample case that the linear programming formulation is suitable to search for a clinically optimal treatment, and that the optimization steps can be performed quickly to establish that a Pareto-efficient solution has been found. Furthermore, it is demonstrated how the stepwise approach is preferable compared to modifying importance factors

Analysis of neurological sequelae from radiosurgery of arteriovenous malformations: how location affects outcome

International Nuclear Information System (INIS)

Flickinger, John C.; Kondziolka, Douglas; Maitz, Ann H.; Lunsford, L. Dade

1998-01-01

Purpose/Objective: To elucidate how the risks of developing temporary and permanent neurological sequelae from radiosurgery for arteriovenous malformations (AVM) are related to AVM location, the addition of stereotactic magnetic resonance (MR) imaging to angiographic targeting, and prior hemorrhage or neurological deficits. Materials and Methods: We evaluated follow-up imaging and clinical data in 332 AVM patients who received gamma knife radiosurgery at the University of Pittsburgh between 1987 and 1994. All patients had regular clinical or imaging follow-up for a minimum of 2 years (range: 24-96 months, median = 45 months). There were 83 patients with MR-assisted planning, 187 with prior hemorrhages, and 143 with prior neurological deficits. Results: Symptomatic postradiosurgery sequelae (any neurological problem including headache) developed in 30 (9%) of 332 patients. Symptoms resolved in 58% of patients within 27 months with a significantly greater proportion (p = 0.006) resolving in patients with Dmin 0.3), including the addition of MR targeting, average radiation dose in 20 cc, prior hemorrhage, or neurological deficit. We used these results to construct a risk prediction model for symptomatic postradiosurgery sequelae. The risk of radiation necrosis was significantly correlated with PIE score (p < 0.048), but not with 12-Gy volume. Conclusion: The risks of developing complications from AVM radiosurgery can be predicted according to location with the PIE score, in conjunction with the 12-Gy treatment volume. Further study of factors affecting persistence of these sequelae (progression to radiation necrosis) is needed

Hypofractionated Stereotactic Radiosurgery in a Large Bilateral Thalamic and Basal Ganglia Arteriovenous Malformation

Directory of Open Access Journals (Sweden)

Janet Lee

2013-01-01

Full Text Available Purpose. Arteriovenous malformations (AVMs in the basal ganglia and thalamus have a more aggressive natural history with a higher morbidity and mortality than AVMs in other locations. Optimal treatment—complete obliteration without new neurological deficits—is often challenging. We present a patient with a large bilateral basal ganglia and thalamic AVM successfully treated with hypofractionated stereotactic radiosurgery (HFSRS with intensity modulated radiotherapy (IMRT. Methods. The patient was treated with hypofractionated stereotactic radiosurgery to 30 Gy at margin in 5 fractions of 9 static fields with a minimultileaf collimator and intensity modulated radiotherapy. Results. At 10 months following treatment, digital subtraction angiography showed complete obliteration of the AVM. Conclusions. Large bilateral thalamic and basal ganglia AVMs can be successfully treated with complete obliteration by HFSRS with IMRT with relatively limited toxicity. Appropriate caution is recommended.

Experience in cervix intraepithelial neoplasia and the in situ carcinoma with radiosurgery

International Nuclear Information System (INIS)

Fajardo Tornes, Yarine; Lau Serrano, Dalgis; Perez Ramirez Fernando

2010-01-01

To expose the results from a longitudinal, prospective and descriptive study conducted in 1 437 patients diagnosed with cervical intraepithelial neoplasm (CIN) and in situ carcinoma (ISC) treated by radiosurgery in the neck pathology consultation of the 'Carlos Manuel de Cespedes' University Provincial Hospital during 2004-2009

Historia magistra vitae (Cic. De or. 2.36). The Prime Objective of Radiosurgery in Acoustic Neurinomas.

Science.gov (United States)

Valentino, V; Benassi, M; Strigari, L

2006-11-30

The central question of stereotaxic radiosurgery in acoustic neurinomas is how to pinpoint its main objective: is it a better alternative to neurosurgery or an option when surgery is unfeasible? This study is a continuation of the article published in 1995 in Acta Neurochirurgica, but benefits from greater experience, more complete analysis and longer supervision of results. The conclusions that can be drawn to date from our own findings and from others in the literature are the following: radiosurgery can be used not only to prevent neurinoma growth and at the same time to preserve the patient's neurological conditions without the risk of complications, but it can also be counted on to provide a cure. However, radiosurgery as an excising device is more insidious than the microsurgical scalpel, since the narrow beam of radiation, directed to a limited target without opening the skull, is invisible. The expression coined by Lars Leksell regarded precisely the innovation he himself conceived in the 'closed skull operation', with reference to its use in cases of acoustic neurinoma as an alternative to traditional surgery. Hence, whatever technique or instruments are involved, it is always a question of interventional neuroradiology or minimally invasive neurosurgery.

Introduction results of radiosurgery technique in cervical pathology consultation. Analysis of five years 2004 – 2009.

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Rafael E. Pérez Castro

2011-06-01

Full Text Available AA cross sectional study and retrospective was performed in patients having cervical intraepithelial neoplasia (CIN, mainly in high grade lesions (CIN II, CIN III and C. In situ, which were treated with radiosurgery technique in the University General Hospital “Camilo Cienfuegos” Sancti Spiritus during the period may 2004 – may 2009 with the objective to evaluate the radiosurgery`s behaviour in the period mentioned before. The studied group was conformed by 550 patients having high grade lesions and low grade persistent lesions (NIC I with previous biopsy, a smaller group of 24 cases was formed by benign pathologies tributary of this procedure. High grade lesions were of major indications (73.1%. 69 cases were false negative (13.3%; since the second decade of life were presented high and low grade lesions of cervical pathology, a good correlation punch – cone byopsy was checked; edges of the surgical section behave properly, lower than what it is established in the international standard (6.7. The procedure had a great economic and social impact, because it is an ambulatory technique with few difficulties, low cost, and a fast integration patient – normal work.

Gamma Knife radiosurgery in pituitary adenomas: Why, who, and how to treat?

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Castinetti, Frederic; Brue, Thierry

2010-08-01

Pituitary adenomas are benign tumors that can be either secreting (acromegaly, Cushing's disease, prolactinomas) or non-secreting. Transsphenoidal neurosurgery is the gold standard treatment; however, it is not always effective. Gamma Knife radiosurgery is a specific modality of stereotactic radiosurgery, a precise radiation technique. Several studies reported the efficacy and low risk of adverse effects induced by this technique: in secreting pituitary adenomas, hypersecretion is controlled in about 50% of cases and tumor volume is stabilized or decreased in 80-90% of cases, making Gamma Knife a valuable adjunctive or first-line treatment. As hormone levels decrease progressively, the main drawback is the longer time to remission (12-60 months), requiring an additional treatment during this period. Hypopituitarism is the main side effect, observed in 20-40% cases. Gamma Knife is thus useful in the therapeutic algorithms of pituitary adenomas in well-defined indications, mainly low secreting small lesions well identified on magnetic resonance imaging (MRI).

Dosimetry of Gamma Knife and linac-based radiosurgery using radiochromic and diode detectors

International Nuclear Information System (INIS)

Somigliana, A.; Borelli, S.; Zonca, G.; Pignoli, E.; Loi, G.; Marchesini, R.; Cattaneo, G.M.; Fiorino, C.; Vecchio, A. del; Calandrino, R.

1999-01-01

In stereotactic radiosurgery the choice of appropriate detectors, whether for absolute or relative dosimetry, is very important due to the steep dose gradient and the incomplete lateral electronic equilibrium. For both linac-based and Leksell Gamma Knife radiosurgery units, we tested the use of calibrated radiochromic film to measure absolute doses and relative dose distributions. In addition a small diode was used to estimate the relative output factors. The data obtained using radiochromic and diode detectors were compared with measurements performed with other conventional methods of dosimetry, with calculated values by treatment planning systems and with data prestored in the treatment planning system supplied by the Leksell Gamma Knife (LGK) vendor. Two stereotactic radiosurgery techniques were considered: Leksell Gamma Knife (using γ-rays from 60 Co) and linac-based radiosurgery (LR) (6 MV x-rays). Different detectors were used for both relative and absolute dosimetry: relative output factors (OFs) were estimated by using radiochromic and radiographic films and a small diode; relative dose distributions in the axial and coronal planes of a spherical polystyrene phantom were measured using radiochromic film and calculated by two different treatment planning systems (TPSs). The absolute dose at the sphere centre was measured by radiochromic film and a small ionization chamber. An accurate selection of radiochromic film was made: samples of unexposed film showing a percentage standard deviation of less than 3% were used for relative dose profiles, and for absolute dose and OF evaluations this value was reduced to 1.5%. Moreover a proper calibration curve was made for each set of measurements. With regard to absolute doses, the results obtained with the ionization chamber are in good correlation with radiochromic film-generated data, for both LGK and LR, showing a dose difference of less than 1%. The output factor evaluations, performed using different methods

Target delineation in radiosurgery for cerebral arteriovenous malformations

International Nuclear Information System (INIS)

Guo, W.Y.; Nordell, B.; Karlsson, B.; Soederman, M.; Lindqvist, M.; Ericson, K.; Franck, A.; Lax, I.; Lindquist, C.

1993-01-01

A study of 6 selected arteriovenous malformation (AVM) patients was performed to investigate the feasibility of delineating an AVM on MR images and to compare the AVM volume outlined on different images. Conventional stereotaxic angiograms, stereotaxic MR images and MR angiograms using several different pulse sequences were obtained prior to radiosurgery. Treatment plans were made from the conventional stereotaxic angiograms. These plans were then transferred to a separate dose planning computer which displayed the MR images with the superimposed isodose lines. The radiated volumes of AVM and brain tissue were measured from these MR images. Last, an assessment was made of the radiation volume needed for an appropriate treatment of the AVM if the treatment plan was made from the MR images rather than from the conventional stereotaxic angiogram. It was possible to delineate medium and large size AVM nidi on stereotaxic MR images based on an integration of information obtained from various pulse sequences. The estimated volumes of the AVM nidi were found to be larger on the conventional stereotaxic angiograms than on the stereotaxic MR images. Consequently, a dose plan based on a conventional stereotaxic angiogram would result in a higher integral dose to the brain with the same target dose. By using reliable MR information it is expected that the volume of brain exposed to radiation could be decreased and the adverse effects of stereotactic radiosurgery for AVM thereby minimized. (orig.)

Gamma knife radiosurgery of acoustic neurinomas

International Nuclear Information System (INIS)

Bertalanffy, A.; Dietrich, W.; Aichholzer, M.; Kitz, K.; Heimberger, K.; Brix, R.

2001-01-01

The authors report on their series of 40 patients with 41 acoustic neurinomas (ACNs), including one patient with bilateral acoustic neurinomas suffering from neurofibromatosis type 2 (NF II) who were treated with the gamma knife unit at their institution between August 1992 and October 1995. Of these 41 tumours, 21 ACNs had been operated on before (l to 4 times), 20 ACNs were exclusively treated by gamma knife radiosurgery (GKRS). The maximal axial tumour diameter ranged from 6 to 33 mm (median: 25 mm), the maximal transverse tumour diameter ranged from 7 mm to 36 mm (median: 16 mm). The dose distributed to the tumour margin was 10 to 17 Gy (median: 12 Gy) by enclosing the tumour with the 40 % to 95 % isodose line (median: 50 % isodose line) and using 1 to 12 isocenters (median: 5 isocenters). Central loss of contrast enhancement was observed in 78 % of the patients within six to 12 months after radiosurgery. Thirty-two patients were observed over a minimum follow up period of at least 36 months, 9 patients were lost to follow up as they died of unrelated causes or refused further check-ups. Within the follow up period of up to seven years, magnetic resonance imaging (MRI) control scans revealed the tumour diameter stable or decreased in 29 cases and increased in three tumours. Of 14 patients with useful hearing before treatment, 9 patients were examined in addition to pure tone audiogramm by measurement of brainstem auditory evoked potentials (BAEPs) one to four years after radiosurgery. None of three patients showed a postoperative loss of the cochlea function. According to slight alterations of the cochlea function (cochlea summating action potential), pure tone audiometry of those patients revealed only slight changes of the hearing level (HL) within a maximum range of ±15 Decibel (dB). The hearing threshold improved in two, was stable in four and deteriorated in three patients, respectively. We observed postradiosurgical aggravation of a pre-existing facial

Gamma knife radiosurgery of acoustic neurinomas

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Bertalanffy, A; Dietrich, W; Aichholzer, M; Kitz, K [Department of Neurosurgery, University of Vienna, Medical School, Vienna (Austria); Heimberger, K [Department of Radiology, Division: Neuroradiology, University of Vienna, Medical School, Vienna (Austria); Brix, R [Department of Otorhinolaryngology, University of Vienna, Medical School, Vienna (Austria)

2001-07-01

The authors report on their series of 40 patients with 41 acoustic neurinomas (ACNs), including one patient with bilateral acoustic neurinomas suffering from neurofibromatosis type 2 (NF II) who were treated with the gamma knife unit at their institution between August 1992 and October 1995. Of these 41 tumours, 21 ACNs had been operated on before (l to 4 times), 20 ACNs were exclusively treated by gamma knife radiosurgery (GKRS). The maximal axial tumour diameter ranged from 6 to 33 mm (median: 25 mm), the maximal transverse tumour diameter ranged from 7 mm to 36 mm (median: 16 mm). The dose distributed to the tumour margin was 10 to 17 Gy (median: 12 Gy) by enclosing the tumour with the 40 % to 95 % isodose line (median: 50 % isodose line) and using 1 to 12 isocenters (median: 5 isocenters). Central loss of contrast enhancement was observed in 78 % of the patients within six to 12 months after radiosurgery. Thirty-two patients were observed over a minimum follow up period of at least 36 months, 9 patients were lost to follow up as they died of unrelated causes or refused further check-ups. Within the follow up period of up to seven years, magnetic resonance imaging (MRI) control scans revealed the tumour diameter stable or decreased in 29 cases and increased in three tumours. Of 14 patients with useful hearing before treatment, 9 patients were examined in addition to pure tone audiogramm by measurement of brainstem auditory evoked potentials (BAEPs) one to four years after radiosurgery. None of three patients showed a postoperative loss of the cochlea function. According to slight alterations of the cochlea function (cochlea summating action potential), pure tone audiometry of those patients revealed only slight changes of the hearing level (HL) within a maximum range of {+-}15 Decibel (dB). The hearing threshold improved in two, was stable in four and deteriorated in three patients, respectively. We observed postradiosurgical aggravation of a pre-existing facial

A theoretical analysis of hemodynamic and biomechanical alterations in intracranial AVMs after radiosurgery

International Nuclear Information System (INIS)

Lo, E.H.

1993-01-01

Stereotactic radiosurgery is being increasingly used to treat intracranial arteriovenous malformations (AVMs). However, successful radiosurgery may involve latent periods of 1-2 years prior to AVM obliteration. This latent period include states of altered flow patterns that may not influence hemorrhage probabilities. The probability of hemorrhage is likely to be related to the degree of biomechanical stress across the AVM shunt walls. This paper describes a theoretical analysis of the altered hemodynamics and biomechanical stresses within AVM shunts post-radiosurgery. The mathematical model is comprised of linked flow compartments that represent the AVM and adjacent normal vasculature. As obliteration of the irradiated shunts occurs, changes in flow rates and pressure gradients are calculated based on first order fluid dynamics. Stress on the AVM shunt walls is calculated based on tangential forces due to intramural pressure. Two basic models are presented: a distribution of shunts with fixed thin walls subject to step-function obliteration, and a distribution of shunts subject to luminal obliteration from slowly thickening walls. Variations on these models are analyzed, including sequential, selective and random shunt obliteration, and uniform or Poisson distributions of shunt radii. Model I reveals that the range of pressure alterations in the radiosurgically-treated AVM include the possibility of transient increases in the total biomechanical stress within the shunt walls prior to obliteration. Model II demonstrates that uniform luminal narrowing via thickened walls should lead to reduced transmural stresses. The precise temporal pattern of AVM flow decrease and biomechanical stress reduction depends on the selection of shunts that are obliterated. 34 refs., 5 figs., 1 tab

Radiosurgery for Para-IAC Meningiomas: The Effect of Radiation Dose to the Cochlea on Hearing Outcome

International Nuclear Information System (INIS)

Kim, Young-Hoon; Kim, Dong Gyu; Han, Jung Ho; Chung, Hyun-Tai; Kim, In Kyung; Song, Sang Woo; Park, Jeong-Hoon; Kim, Jin Wook; Kim, Yong Hwy; Park, Chul-Kee; Kim, Chae-Yong; Paek, Sun Ha; Jung, Hee-Won

2012-01-01

Purpose: This study was performed to assess the radiosurgical results of meningiomas extending into the internal acoustic canal (para-IAC meningiomas), with a particular focus on the effect of radiation dose to the cochlea on hearing outcome. Methods and Materials: A total of 50 patients who underwent radiosurgery for para-IAC meningiomas between 1998 and 2009, which were followed for 2 years, were enrolled. The mean age was 55.8 years (range, 15–75). The mean tumor volume was 6.1 cm 3 (range, 1.0–19.0), the mean tumor length in the IAC was 6.9 mm (range, 1.3–13.3), and the mean prescribed marginal dose was 13.1 Gy (range, 10–15) at an isodose line of 50%. The mean follow-up duration was 46 months (range, 24–122). Results: Eight (16.0%) patients had nonserviceable hearing at the time of surgery. At the last follow-up, the tumor control rate was 94%; unchanged in 17 patients, decreased in 30 patients, and increased in 3 patients. Among 42 patients with serviceable hearing at the time of radiosurgery, it was preserved in 41 (97.6%) patients at the last follow-up. The maximal and mean radiation doses to the cochleae of these 41 patients were 5.8 Gy ± 0.3 (range, 3.1–11.5) and 4.3 Gy ± 0.2 (range, 2.2–7.5), respectively. The maximal dose to the cochlea of the patient who lost hearing after radiosurgery was 4.7 Gy. Conclusions: The radiation dose to the cochlea may have the minimal toxic effect on the hearing outcome in patients who undergo radiosurgery for para-IAC meningiomas.

Peritumoral hemorrhage immediately after radiosurgery for metastatic brain tumor

International Nuclear Information System (INIS)

Uchino, Masafumi; Kitajima, Satoru; Miyazaki, Chikao; Otsuka, Takashi; Seiki, Yoshikatsu; Shibata, Iekado

2003-01-01

We report a case of a 44-year-old woman with metastatic brain tumors who suffered peri-tumoral hemorrhage soon after stereotactic radiosurgery (SRS). She had been suffering from breast cancer with multiple systemic metastasis. She started to have headache, nausea, dizziness and speech disturbance 1 month before admission. There was no bleeding tendency in the hematological examination and the patient was normotensive. Neurological examination disclosed headache and slightly aphasia. Magnetic resonance imaging showed a large round mass lesion in the left temporal lobe. It was a well-demarcated, highly enhanced mass, 45 mm in diameter. SRS was performed on four lesions in a single session (Main mass: maximum dose was 30 Gy in the center and 20 Gy in the margin of the tumor. Others: maximum 25 Gy margin 20 Gy). After radiosurgery, she had severe headache, nausea and vomiting and showed progression of aphasia. CT scan revealed a peritumoral hemorrhage. Conservative therapy was undertaken and the patient's symptoms improved. After 7 days, she was discharged, able to walk. The patient died of extensive distant metastasis 5 months after SRS. Acute transient swelling following conventional radiotherapy is a well-documented phenomenon. However, the present case indicates that such an occurrence is also possible in SRS. We have hypothesized that acute reactions such as brain swelling occur due to breakdown of the fragile vessels of the tumor or surrounding tissue. (author)

Management of supratentorial cavernous malformations: craniotomy versus gammaknife radiosurgery.

Science.gov (United States)

Shih, Yang-Hsin; Pan, David Hung-Chi

2005-02-01

Although craniotomy is the preferred treatment for symptomatic solitary supratentorial cavernous malformation (CM), radiosurgery is also an option. Our aim was to see which of these strategies was the most effective and under what circumstances. Of the 46 patients with solitary supratentorial CM that we retrospectively studied, 24 presented with seizures, 16 with focal neurological deficits due to intracerebral hemorrhage, and 6 with both seizures and bleeding. Sixteen were treated with craniotomy and 30 with gammaknife radiosurgery (GKRS). The main outcome measures for comparing craniotomy with GKRS were the proportion of postoperative seizure-free patients and the proportion of patients in whom no rebleeding occurred. Of patients presenting with seizures with/without bleeding, a significantly higher proportion of the craniotomy group than the GKRS group became and remained seizure-free (11/14 [79%] versus 4/16 [25%]; P < 0.002), and of those presenting with bleeding with/without seizures, a somewhat (though nonsignificantly) higher proportion did not rebleed (4/4 [100%] versus 12/18 [67%]) after surgery. The remaining 2 of the 16 craniotomy patients did not rebleed and had no residual tumor at follow up. Twelve of the 30 GKRS patients had evidence of tumor regression at follow up. In the clinical management of solitary supratentorial CM, craniotomy for lesionectomy resulted in better seizure control and rebleeding avoidance than GKRS.

Motion detection system with GPU acceleration for stereotactic radiosurgery

International Nuclear Information System (INIS)

Yamakawa, Takuya; Ogawa, Koichi; Iyatomi, Hitoshi; Usui, Keisuke; Kunieda, Etsuo; Shigematsu, Naoyuki

2012-01-01

Stereotactic radiosurgery is a non-invasive method for the treatment of tumors that employs a narrow, high-energy X-ray beam. In this form of therapy, the target region is intensively irradiated with the narrow beam, and any unexpected patient motion may therefore lead to undesirable irradiation of neighboring normal tissues and organs. To overcome this problem, we propose a contactless motion detection system with three USB cameras for use in stereotactic radiosurgery of the head and neck. In our system, the three cameras monitor images of the patient's nose and ears, and patient motion is detected using a template-matching method. If patient motion is detected, the system alerts the radiologist to turn off the beam. We reduced the effects of variations in the lighting in the irradiation room by employing USB cameras sensitive to infrared light. To detect movement in the acquired images, we use a template-matching method that is realized with general-purpose computing-on-graphics processing units. In this paper, we present an outline of our proposed motion detection system based on monitoring of images of the patient acquired with infrared USB cameras and a template-matching method. The performance of the system was evaluated under the same conditions as those used in actual radiation therapy of the head and neck. (author)

Serial MRI of vestibular schwannoma presenting transient enlargement associated with intratumoral hemorrhage following radiosurgery. Two case reports

International Nuclear Information System (INIS)

Kikuchi, Yasuhiro; Watanabe, Kazuo; Goto, Hiromi; Isaki, Kenji; Sato, Sonomi

2010-01-01

Two cases of vestibular schwannoma showing transient enlargement with hemorrhage that was recognized on T2 or T2*-weighted MR image are reported. Case 1: A 72-year-old woman had a recurrent cystic lesion after resection and stereotactic radiosurgery (SRS). After retreatment by gamma knife radiosurgery, the cystic component further expanded with a fluid-fluid level, and T2 or T2*-weighted image showed markedly-low signal in the parenchymal component. Chronic hemorrhage from the cyst wall injured by irradiation is probably related to expansion of the cyst. Case 2: A 59-year-old woman received SRS. Serial MRI scans demonstrated a lesion continually expanding with homogeneous contrast enhancement on T1-weighted images. At 64 months after treatment, a central portion with high blood flow surrounded by a markedly-low intensity component of apparent hemorrhage on T2*-weighted MRI was identified. The lesion decreased in size after 73 months. Hemorrhage might occur from the neogenetic angioma-like tissue induced by irradiation effect in the tumor. Based on these observations, microvasculopathy associated with irradiation is a probable mechanism that induces bleeding in vestibular schwannoma following radiosurgery. (author)

Enhanced intrinsic radiosensitivity after treatment with stereotactic radiosurgery for an acoustic neuroma

International Nuclear Information System (INIS)

Adams, Gerard; Martin, Olga A.; Roos, Daniel E.; Lobachevsky, Pavel N.; Potter, Andrew E.; Zacest, Andrew C.; Bezak, Eva; Bonner, William M.; Martin, Roger F.; Leong, Trevor

2012-01-01

Enhanced radiosensitivity is an uncommon phenomenon attributable to deficient DNA repair after radiotherapy which can be assessed with the γ-H2AX assay. Reports of radiosensitivity after stereotactic radiosurgery (SRS) are uncommon. We describe a case where the clinical, radiological and laboratory findings suggest enhanced radiosensitivity after SRS for an acoustic neuroma.

ΔOSI: a prototype microstrip dosimeter for characterization of medical radiotherapy and radiosurgery systems

International Nuclear Information System (INIS)

Redondo-Fernandez, I.; Buttar, C.; Walsh, S.; Manolopoulos, S.; Homer, J.M.; Young, S.; Conway, J.

2006-01-01

As the technology for medical radiotherapy and radiosurgery evolves, there is a growing need for dosimeters capable of measuring dose distributions on-line with submillimeter spatial resolution, both for facility commissioning and patient-related quality assurance. We have designed and built a high spatial resolution dosimeter based on silicon micro-strip technology for characterization of small radiotherapy and radiosurgery fields. The aim is to provide relative dosimetry measurement with film-like spatial resolution and to be able to resolve the temporal evolution. Following the description of the prototypes, first beam test results of a 250 μm pitch, 128 channels prototype with X-rays in a clinical 6 MV accelerator are presented. The device demonstrated good dosimetric capabilities when compared to reference measurements made with ionization chambers and agrees with radiographic film in the steep dose gradient region produced by the collimator edge

The use of single fraction Leksell stereotactic radiosurgery in the treatment of uveal melanoma

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Rennie, I. [Univ. of Sheffield, Dept. of Ophthalmology and Orthoptics (United Kingdom); Forster, D.; Kemeny, A. [Royal Hallamshire Hospital, Dept. of Neurosurgery (United Kingdom); Walton, L. [Royal Hallamshire Hospital, Dept. of Medical Physics (United Kingdom); Kunkler, I. [Weston Park Hospital, Dept. of Radiotherapy, Sheffield (United Kingdom)

1996-11-01

Fourteen patients with posterior uveal melanomas were treated using single fraction stereotactic radiosurgery. In each case a dose of 70 Gy was administered to the periphery of the tumour. Regression of the tumour has been observed in 13 patients, whilst the lesion has remained unchanged in one patient. The visual acuity has deteriorated in all 14 patients. Significant radiation induced adverse reactions were noted in 13 patients and include; retinopathy, optic neuropathy, rubeosis iridis, and secondary glaucoma. Two patients have required enucleation because of intractable rubeotic glaucoma. One patient has died from proven metastases. Although stereotactic radiosurgery appears to be a practical and effective method of treating uveal melanomas, its usefulness is limited by a high incidence of radiation induced adverse reactions. Further works is required to refine the current treatment protocol and establish an optimal prescription dose. (au) 30 refs.

The use of single fraction Leksell stereotactic radiosurgery in the treatment of uveal melanoma

International Nuclear Information System (INIS)

Rennie, I.; Forster, D.; Kemeny, A.; Walton, L.; Kunkler, I.

1996-01-01

Fourteen patients with posterior uveal melanomas were treated using single fraction stereotactic radiosurgery. In each case a dose of 70 Gy was administered to the periphery of the tumour. Regression of the tumour has been observed in 13 patients, whilst the lesion has remained unchanged in one patient. The visual acuity has deteriorated in all 14 patients. Significant radiation induced adverse reactions were noted in 13 patients and include; retinopathy, optic neuropathy, rubeosis iridis, and secondary glaucoma. Two patients have required enucleation because of intractable rubeotic glaucoma. One patient has died from proven metastases. Although stereotactic radiosurgery appears to be a practical and effective method of treating uveal melanomas, its usefulness is limited by a high incidence of radiation induced adverse reactions. Further works is required to refine the current treatment protocol and establish an optimal prescription dose. (au) 30 refs

Linac-based radiosurgery of cerebral melanoma metastases. Analysis of 122 metastases treated in 64 patients

International Nuclear Information System (INIS)

Herfarth, K.K.; Pirzkall, A.; Izwekowa, O.; Wannenmacher, M.; Thilmann, C.; Debus, J.; Delorme, S.; Hofmann, U.; Schadendorf, D.; Zierhut, D.

2003-01-01

Purpose: Stereotactic radiosurgery is an alternative option to neurosurgical excision in the management of patients with brain metastases. We retrospectively analyzed patients with brain metastases of malignant melanoma who were treated at our institution for outcome and prognostic factors. Patients and Methods: 64 patients with 122 cerebral metastases were treated with stereotactic radiosurgery between 1986 and 2000. Twelve patients (19%) showed neurologic symptoms at the time of treatment, and 46 patients (72%) had extracerebral tumor manifestation at that time. The median dose to the 80% isodose line, prescribed to encompass the tumor margin, was 20 Gy (range, 15-22 Gy). Results: Neurologic symptoms improved in five of twelve symptomatic patients. 41 patients remained asymptomatic or unchanged in their neurologic symptoms. Only five patients (8%) temporarily worsened neurologically after therapy despite no signs of tumor progression. With a mean follow-up time of 9.4 months, actuarial local control was 81% after 1 year. There was a statistically significant dose and size dependency of local tumor control. Median actuarial survival after treatment was 10.6 months. Patients without extracerebral tumor manifestation showed a superior survival (p = 0.04). Conclusions: Despite high local tumor control rates, the prognosis of patients with cerebral metastases of malignant melanoma remains poor. Stereotactic radiosurgery has the potential of stabilizing or improving neurologic symptoms in these patients in a palliative setting. (orig.)

Assessment of absorbed dose to thyroid, parotid and ovaries in patients undergoing Gamma Knife radiosurgery

International Nuclear Information System (INIS)

Hasanzadeh, H; Sharafi, A; Verdi, M Allah; Nikoofar, A

2006-01-01

Stereotactic radiosurgery was originally introduced by Lars Leksell in 1951. This treatment refers to the noninvasive destruction of an intracranial target localized stereotactically. The purpose of this study was to identify the dose delivered to the parotid, ovaries, testis and thyroid glands during the Gamma Knife radiosurgery procedure. A three-dimensional, anthropomorphic phantom was developed using natural human bone, paraffin and sodium chloride as the equivalent tissue. The phantom consisted of a thorax, head and neck and hip. In the natural places of the thyroid, parotid (bilateral sides) and ovaries (midline), some cavities were made to place TLDs. Three TLDs were inserted in a batch with 1 cm space between the TLDs and each batch was inserted into a single cavity. The final depth of TLDs was 3 cm from the surface for parotid and thyroid and was 15 cm for the ovaries. Similar batches were placed superficially on the phantom. The phantom was gamma irradiated using a Leksell model C Gamma Knife unit. Subsequently, the same batches were placed superficially over the thyroid, parotid, testis and ovaries in 30 patients (15 men and 15 women) who were undergoing radiosurgery treatment for brain tumours. The mean dosage for treating these patients was 14.48 ± 3.06 Gy (10.5-24 Gy) to a mean tumour volume of 12.30 ± 9.66 cc (0.27-42.4 cc) in the 50% isodose curve. There was no significant difference between the superficial and deep batches in the phantom studies (P-value < 0.05). The mean delivered doses to the parotid, thyroid, ovaries and testis in human subjects were 21.6 ± 15.1 cGy, 9.15 ± 3.89 cGy, 0.47 ± 0.3 cGy and 0.53 ± 0.31 cGy, respectively. The data can be used in making decisions for special clinical situations such as treating pregnant patients or young patients with benign lesions who need radiosurgery for eradication of brain tumours

Is it sufficient to repeat LINEAR accelerator stereotactic radiosurgery in choroidal melanoma?

Science.gov (United States)

Furdova, A; Horkovicova, K; Justusova, P; Sramka, M

One day session LINAC based stereotactic radiosurgery (SRS) at LINAC accelerator is a method of "conservative" attitude to treat the intraocular malignant uveal melanoma. We used model Clinac 600 C/D Varian (system Aria, planning system Corvus version 6.2 verification IMRT OmniPro) with 6 MeV X by rigid immobilization of the eye to the Leibinger frame. The stereotactic treatment planning after fusion of CT and MRI was optimized according to the critical structures (lens, optic nerve, also lens and optic nerve at the contralateral side, chiasm). The first plan was compared and the best plan was applied for therapy at C LINAC accelerator. The planned therapeutic dose was 35.0 Gy by 99 % of DVH (dose volume histogram). In our clinical study in the group of 125 patients with posterior uveal melanoma treated with SRS, in 2 patients (1.6 %) was repeated SRS indicated. Patient age of the whole group ranged from 25 to 81 years with a median of 54 TD was 35.0 Gy. In 2 patients after 5 year interval after stereotactic radiosurgery for uveal melanoma stage T1, the tumor volume increased to 50 % of the primary tumor volume and repeated SRS was necessary. To find out the changes in melanoma characteristics after SRS in long term interval after irradiation is necessary to follow up the patient by an ophthalmologist regularly. One step LINAC based stereotactic radiosurgery with a single dose 35.0 Gy is one of treatment options to treat T1 to T3 stage posterior uveal melanoma and to preserve the eye globe. In some cases it is possible to repeat the SRS after more than 5 year interval (Fig. 8, Ref. 23).

Stereotactic Radiosurgery for Benign (World Health Organization Grade I) Cavernous Sinus Meningiomas-International Stereotactic Radiosurgery Society (ISRS) Practice Guideline: A Systematic Review.

Science.gov (United States)

Lee, Cheng-Chia; Trifiletti, Daniel M; Sahgal, Arjun; DeSalles, Antonio; Fariselli, Laura; Hayashi, Motohiro; Levivier, Marc; Ma, Lijun; Álvarez, Roberto Martínez; Paddick, Ian; Regis, Jean; Ryu, Samuel; Slotman, Ben; Sheehan, Jason

2018-03-15

Stereotactic radiosurgery (SRS) has become popular as a standard treatment for cavernous sinus (CS) meningiomas. To summarize the published literature specific to the treatment of CS meningioma with SRS found through a systematic review, and to create recommendations on behalf of the International Stereotactic Radiosurgery Society. Articles published from January 1963 to December 2014 were systemically reviewed. Three electronic databases, PubMed, EMBASE, and The Cochrane Central Register of Controlled Trials, were searched. Publications in English with at least 10 patients (each arm) were included. Of 569 screened abstracts, a total of 49 full-text articles were included in the analysis. All studies were retrospective. Most of the reports had favorable outcomes with 5-yr progression-free survival (PFS) rates ranging from 86% to 99%, and 10-yr PFS rates ranging from 69% to 97%. The post-SRS neurological preservation rate ranged from 80% to 100%. Resection can be considered for the treatment of larger (>3 cm in diameter) and symptomatic CS meningioma in patients both receptive to and medically eligible for open surgery. Adjuvant or salvage SRS for residual or recurrent tumor can be utilized depending on factors such as tumor volume and proximity to adjacent critical organs at risk. The literature is limited to level III evidence with respect to outcomes of SRS in patients with CS meningioma. Based on the observed results, SRS offers a favorable benefit to risk profile for patients with CS meningioma.

Stereotactic radiosurgery for brainstem metastases: Survival, tumor control, and patient outcomes

International Nuclear Information System (INIS)

Hussain, Aamir; Brown, Paul D.; Stafford, Scott L.; Pollock, Bruce E.

2007-01-01

Purpose: Patients with brainstem metastases have limited treatment options. In this study, we reviewed outcomes after stereotactic radiosurgery (SRS) in the management of patients with brainstem metastases. Methods and Materials: Records were reviewed of 22 consecutive patients presenting with brainstem metastases who underwent SRS. The most frequent primary malignancy was the lung (n = 11), followed by breast (n = 3) and kidney (n = 2). Three patients (14%) also underwent whole-brain radiation therapy (WBRT). The median tumor volume was 0.9 mL (range, 0.1-3.3 mL); the median tumor margin dose was 16 Gy (range, 14-23 Gy). Results: Median survival time after SRS was 8.5 months. Although local tumor control was achieved in all patients with imaging follow-up (n = 19), 5 patients died from development and progression of new brain metastases. Two patients (9%) had symptom improvement after SRS, whereas 1 patient (5%) developed a new hemiparesis after SRS. Conclusions: Radiosurgery is safe and provides a high local tumor control rate for patients with small brainstem metastases. Patients with limited systemic disease and good performance status should be strongly considered for SRS

Radiosurgery for metastatic disease at the craniocervical junction.

Science.gov (United States)

Tuchman, Alexander; Yu, Cheng; Chang, Eric L; Kim, Paul E; Rusch, Mairead C; Apuzzo, Michael L J

2014-12-01

Metastatic disease of the craniovertebral junction (CVJ) can cause pain, cranial nerve deficits, occipitocervical instability, or brainstem/spinal cord compression if left untreated. Many patients with metastasis in this region have a high burden of systemic disease and short life expectancy, making them poor candidates for aggressive surgical resections and fusion procedures. Traditionally, symptom palliation and local disease control in these patients has been achieved through conventional radiation therapy. Stereotactic radiosurgery (SRS) has the advantage of precisely delivering radiation to a target in fewer fractions. To our knowledge, we report the results of the largest series of patients with CVJ metastasis treated with stereotactic radiosurgery. We performed a retrospective review of 9 consecutive patients with 10 tumors of the CVJ treated with SRS at the Keck Medical Center of the University of Southern California. Two tumors were treated with Gamma Knife, whereas the other 8 received CyberKnife. The median marginal dose was 20 Gy (16-24 Gy) over 1-5 fractions. Point maximal dose to the brainstem or spinal cord ranged between 8 and 18.9 Gy. Median survival was 4 months (1-51 months). Five of six patients presenting with pain had at least partial symptom resolution. No patient went on to require surgical decompression or fusion, and there were no complications directly related to SRS. In well-selected patients, SRS for metastatic lesions of the CVJ has a low risk for complications or treatment failure, while achieving a high rate of palliation of pain symptoms. Copyright © 2014 Elsevier Inc. All rights reserved.

SU-F-T-576: Characterization of Two Dimensional Liquid Filled Detector Array(SRS 1000) in High Precision Cyberknife Robotic Radiosurgery System

International Nuclear Information System (INIS)

Muthukumaran, M; Manigandan, D; Murali, V; Chitra, S; Ganapathy, K; Vikraman, S

2016-01-01

Purpose: The aim of the study is to characterize a two dimensional liquid filled detector array SRS 1000 for routine QA in Cyberknife Robotic Radiosurgery system. Methods: SRS 1000 consists of 977 liquid filled ionization chambers and is designed to be used in small field SRS/SBRT techniques. The detector array has got two different spacial resolutions. Till field size of 5.5×5.5 cm the spacial resolution is 2.5mm (center to center) and after that till field size of 11 × 11 cm the spacial resolution is 5mm. The size of the detector is 2.3 × 2.3 0.5 mm with a volume of .003 cc. The CyberKnife Robotic Radiosurgery System is a frameless stereotactic radiosurgery system in which a LINAC is mounted on a robotic manipulator to deliver beams with a high sub millimeter accuracy. The SRS 1000’s MU linearity, stability, reproducibility in Cyberknife Robotic Radiosurgery system was measured and investigated. The output factors for fixed and IRIS collimators for all available collimators (5mm till 60 mm) was measured and compared with the measurement done with PTW pin-point ionization chamber. Results: The MU linearity was measured from 2 MU till 1000 MU for doserates in the range of 700cGy/min – 780 cGy/min and compared with the measurement done with pin point chamber The MU linearity was with in 3%. The detector arrays stability and reproducibility was excellent and was withinin 0.5% The measured output factors showed an agreement of better than 2% when compared with the measurements with pinpoint chamber for both fixed and IRIS collimators with all available field sizes. Conclusion: We have characterised PTW 1000 SRS as a precise and accurate measurement tool for routine QA of Cyberknife Robotic radiosurgery system.

SU-F-T-576: Characterization of Two Dimensional Liquid Filled Detector Array(SRS 1000) in High Precision Cyberknife Robotic Radiosurgery System

Energy Technology Data Exchange (ETDEWEB)

Muthukumaran, M [Apollo Speciality Hospitals, Chennai, Tamil Nadu (India); Manigandan, D [Fortis Cancer Institute, Mohali, Punjab (India); Murali, V; Chitra, S; Ganapathy, K [Apollo Speciality Hospital, Chennai, Tamil Nadu (India); Vikraman, S [Jaypee Hospital – Radiation Onology, Noida, UTTAR PRADESH (India)

2016-06-15

Purpose: The aim of the study is to characterize a two dimensional liquid filled detector array SRS 1000 for routine QA in Cyberknife Robotic Radiosurgery system. Methods: SRS 1000 consists of 977 liquid filled ionization chambers and is designed to be used in small field SRS/SBRT techniques. The detector array has got two different spacial resolutions. Till field size of 5.5×5.5 cm the spacial resolution is 2.5mm (center to center) and after that till field size of 11 × 11 cm the spacial resolution is 5mm. The size of the detector is 2.3 × 2.3 0.5 mm with a volume of .003 cc. The CyberKnife Robotic Radiosurgery System is a frameless stereotactic radiosurgery system in which a LINAC is mounted on a robotic manipulator to deliver beams with a high sub millimeter accuracy. The SRS 1000’s MU linearity, stability, reproducibility in Cyberknife Robotic Radiosurgery system was measured and investigated. The output factors for fixed and IRIS collimators for all available collimators (5mm till 60 mm) was measured and compared with the measurement done with PTW pin-point ionization chamber. Results: The MU linearity was measured from 2 MU till 1000 MU for doserates in the range of 700cGy/min – 780 cGy/min and compared with the measurement done with pin point chamber The MU linearity was with in 3%. The detector arrays stability and reproducibility was excellent and was withinin 0.5% The measured output factors showed an agreement of better than 2% when compared with the measurements with pinpoint chamber for both fixed and IRIS collimators with all available field sizes. Conclusion: We have characterised PTW 1000 SRS as a precise and accurate measurement tool for routine QA of Cyberknife Robotic radiosurgery system.

Atlas-based identification of targets for functional radiosurgery

International Nuclear Information System (INIS)

Stancanello, Joseph; Romanelli, Pantaleo; Modugno, Nicola; Cerveri, Pietro; Ferrigno, Giancarlo; Uggeri, Fulvio; Cantore, Giampaolo

2006-01-01

Functional disorders of the brain, such as Parkinson's disease, dystonia, epilepsy, and neuropathic pain, may exhibit poor response to medical therapy. In such cases, surgical intervention may become necessary. Modern surgical approaches to such disorders include radio-frequency lesioning and deep brain stimulation (DBS). The subthalamic nucleus (STN) is one of the most useful stereotactic targets available: STN DBS is known to induce substantial improvement in patients with end-stage Parkinson's disease. Other targets include the Globus Pallidus pars interna (GPi) for dystonia and Parkinson's disease, and the centromedian nucleus of the thalamus (CMN) for neuropathic pain. Radiosurgery is an attractive noninvasive alternative to treat some functional brain disorders. The main technical limitation to radiosurgery is that the target can be selected only on the basis of magnetic resonance anatomy without electrophysiological confirmation. The aim of this work is to provide a method for the correct atlas-based identification of the target to be used in functional neurosurgery treatment planning. The coordinates of STN, CMN, and GPi were identified in the Talairach and Tournoux atlas and transformed to the corresponding regions of the Montreal Neurological Institute (MNI) electronic atlas. Binary masks describing the target nuclei were created. The MNI electronic atlas was deformed onto the patient magnetic resonance imaging-T1 scan by applying an affine transformation followed by a local nonrigid registration. The first transformation was based on normalized cross correlation and the second on optimization of a two-part objective function consisting of similarity criteria and weighted regularization. The obtained deformation field was then applied to the target masks. The minimum distance between the surface of an implanted electrode and the surface of the deformed mask was calculated. The validation of the method consisted of comparing the electrode-mask distance to

Outcome of radiosurgery treatment with a linear accelerator in patients with trigeminal neuralgia.

Science.gov (United States)

Cordero Tous, N; Cruz Sabido, J de la; Román Cutillas, A M; Saura Rojas, E J; Jorques Infante, A M; Olivares Granados, G

2017-04-01

An overview of the effectiveness of radiosurgery in patients diagnosed with trigeminal neuralgia with an analysis of potential predictors of good outcome. All patients treated with linear accelerator radiosurgery between 2004 and 2011 were analysed. A dose of 60Gy dose was administered 1 to 2mm from the root entry zone with a maximum isodose of 20% delivered to the brainstem. Clinical results for pain control and any side effects were analysed at 12 and 36 months (BNI score). The study included 71 patients (mean follow-up 50.5 months). Pain improvement at 12 months was observed in 68.11% of the total (28.98% with BNI score i-ii; 39.12% with BNI score iii) and at 36 months in 58.21% (23.88% BNI score i-ii; 34.32% BNI score iii). Average recovery time was 3.69 months and the relapse rate was 44.68%. Patients with typical pain displayed statistically significant differences in improvement rates at 12 and at 36 months (P<047 and P<.002). Onset of improvement was analysed using Kaplan-Meyer plots. Statistically significant differences were observed between patients with typical and atypical pain at 36 months (P<.012) in Kaplan-Meyer plots. Side effects were recorded in 15 patients (20.89%), including 9 cases of facial numbness (13.43%); only 2 cases were clinically relevant (2.98%). According to our results, radiosurgery is an effective treatment for trigeminal neuralgia, with few side effects. Typical pain seems to be a good predictor of pain relief. Copyright © 2015 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

Geometrical and dosimetrical characterization of the photon source using a micro-multileaf collimator for stereotactic radiosurgery

International Nuclear Information System (INIS)

Treuer, H; Hoevels, M; Luyken, K; Hunsche, S; Kocher, M; Mueller, R-P; Sturm, V

2003-01-01

A micro-multileaf collimator (μMLC) for stereotactic radiosurgery is used for determination of the spatial intensity distribution of the photon source of a linear accelerator. The method is based on grid field dose measurements using film dosimetry and is easy to perform. Since the μMLC does not allow 'direct' imaging of the photon source, special software has been developed to analyse grid field measurements. Besides the source-density function, grid field analysis yields the position of the focal spot in the room laser coordinate system of the linear accelerator and the position of the treatment head rotation axis and the inclination angle of the leaf bank. Thus the method can be used for base dosimetry and for quality assurance in radiosurgery using a μMLC

Verification of gamma knife based fractionated radiosurgery with newly developed head-thorax phantom

International Nuclear Information System (INIS)

Bisht, Raj Kishor; Kale, Shashank Sharad; Natanasabapathi, Gopishankar; Singh, Manmohan Jit; Agarwal, Deepak; Garg, Ajay; Rath, Goura Kishore; Julka, Pramod Kumar; Kumar, Pratik; Thulkar, Sanjay; Sharma, Bhawani Shankar

2016-01-01

Objective: Purpose of the study is to verify the Gamma Knife Extend™ system (ES) based fractionated stereotactic radiosurgery with newly developed head-thorax phantom. Methods: Phantoms are extensively used to measure radiation dose and verify treatment plan in radiotherapy. A human upper body shaped phantom with thorax was designed to simulate fractionated stereotactic radiosurgery using Extend™ system of Gamma Knife. The central component of the phantom aids in performing radiological precision test, dosimetric evaluation and treatment verification. A hollow right circular cylindrical space of diameter 7.0 cm was created at the centre of this component to place various dosimetric devices using suitable adaptors. The phantom is made of poly methyl methacrylate (PMMA), a transparent thermoplastic material. Two sets of disk assemblies were designed to place dosimetric films in (1) horizontal (xy) and (2) vertical (xz) planes. Specific cylindrical adaptors were designed to place thimble ionization chamber inside phantom for point dose recording along xz axis. EBT3 Gafchromic films were used to analyze and map radiation field. The focal precision test was performed using 4 mm collimator shot in phantom to check radiological accuracy of treatment. The phantom head position within the Extend™ frame was estimated using encoded aperture measurement of repositioning check tool (RCT). For treatment verification, the phantom with inserts for film and ion chamber was scanned in reference treatment position using X-ray computed tomography (CT) machine and acquired stereotactic images were transferred into Leksell Gammaplan (LGP). A patient treatment plan with hypo-fractionated regimen was delivered and identical fractions were compared using EBT3 films and in-house MATLAB codes. Results: RCT measurement showed an overall positional accuracy of 0.265 mm (range 0.223 mm–0.343 mm). Gamma index analysis across fractions exhibited close agreement between LGP and film

Conformity of LINAC-Based Stereotactic Radiosurgery Using Dynamic Conformal Arcs and Micro-Multileaf Collimator

International Nuclear Information System (INIS)

Hazard, Lisa J.; Wang, Brian; Skidmore, Thomas B.; Chern, Shyh-Shi; Salter, Bill J.; Jensen, Randy L.; Shrieve, Dennis C.

2009-01-01

Purpose: To assess the conformity of dynamic conformal arc linear accelerator-based stereotactic radiosurgery and to describe a standardized method of isodose surface (IDS) selection. Methods and Materials: In 174 targets, the conformity index (CI) at the prescription IDS used for treatment was calculated as CI = (PIV/PVTV)/(PVTV/TV), where TV is the target volume, PIV (prescription isodose volume) is the total volume encompassed by the prescription IDS, and PVTV is the TV encompassed by the IDS. In addition, a 'standardized' prescription IDS (sIDS) was chosen according to the following criteria: 95% of the TV was encompassed by the PIV and 99% of TV was covered by 95% of the prescription dose. The CIs at the sIDS were also calculated. Results: The median CI at the prescription IDS and sIDS was 1.63 and 1.47, respectively (p < 0.001). In 132 of 174 cases, the volume of normal tissue in the PIV was reduced by the prescription to the sIDS compared with the prescription IDS, in 20 cases it remained unchanged, and in 22 cases it was increased. Conclusion: The CIs obtained with linear accelerator-based stereotactic radiosurgery are comparable to those previously reported for gamma knife stereotactic radiosurgery. Using a uniform method to select the sIDS, adequate target coverage was usually achievable with prescription to an IDS greater than that chosen by the treating physician (prescription IDS), providing sparing of normal tissue. Thus, the sIDS might aid physicians in identifying a prescription IDS that balances coverage and conformity

Analytical calculation of central-axis dosimetric data for a dedicated 6-MV radiosurgery linear accelerator

Energy Technology Data Exchange (ETDEWEB)

Yang, James N.; Pino, Ramiro [Department of Radiation Physics, Unit 94, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030 (United States); Department of Radiology, Baylor College of Medicine and Methodist Hospital, Houston, Texas 77030 (United States)

2008-10-15

Narrow beams are extensively used in stereotactic radiosurgery. The accuracy of treatment planning dose calculation depends largely on how well the dosimetric data are measured during the machine commissioning. Narrow beams are characterized by the lack of lateral electronic equilibrium. The lateral electronic disequilibrium in the radiation field and detector's finite size are likely to compromise the accuracy in dose measurements in these beams. This may have a profound impact on outcome in patients who undergo stereotactic radiosurgery. To confirm the measured commissioning data for a dedicated 6-MV linear accelerator-based radiosurgery system, we developed an analytical model to calculate the narrow photon beam central-axis dose. This model is an extension of a previously reported method of Nizin and Mooij for the calculation of the absorbed dose under lateral electronic disequilibrium conditions at depth of d{sub max} or greater. The scatter factor and tissue-maximum ratio were calculated for narrow beams using the parametrized model and compared to carefully measured results for the same beams. For narrow beam radii ranging from 0.2 to 1.5 cm, the differences between the analytical and measured scatter factors were no greater than 1.4%. In addition, the differences between the analytical and measured tissue-maximum ratios were within 3.3% for regions greater than the maximum dose depth. The estimated error of this analytical calculation was less than 2%, which is sufficient to validate measurement results.

Gamma Knife radiosurgery for cerebral arteriovenous malformations in children/adolescents and adults. Part I: Differences in epidemiologic, morphologic, and clinical characteristics, permanent complications, and bleeding in the latency period

International Nuclear Information System (INIS)

Nicolato, Antonio; Lupidi, Francesco; Sandri, Marco F.; Foroni, Roberto; Zampieri, Piergiuseppe; Mazza, Carlo; Maluta, Sergio; Beltramello, Alberto; Gerosa, Massimo

2006-01-01

Purpose: To compare the epidemiologic, morphologic, and clinical characteristics of 92 children/adolescents (Group A) and 362 adults (Group B) with cerebral arteriovenous malformations (cAVMs) considered suitable for radiosurgery; to correlate radiosurgery-related permanent complication and post-radiosurgery bleeding rates in the 75 children/adolescents and 297 adults available for follow-up. Methods and Materials: Radiosurgery was performed with a model C 201-source Co 6 Leksell Gamma Unit (Elekta Instruments, Stockholm, Sweden). Fisher exact two-tailed, Wilcoxon rank-sum, and two-sample binomial exact tests were used for statistical analysis. Results: There were significant differences between the two populations in sex (p = 0.015), clinical presentation (p = 0.001), and location (p = 0.008). The permanent complication rate was lower in younger (1.3%) than in older patients (5.4%), although the difference was not significant (p = 0.213). The postradiosurgery bleeding rate was lower in Group A (1.3%) than in Group B (2.7%) (p = 0.694), with global actuarial bleeding rates of 0.56% per year and 1.15% per year, respectively. Conclusions: The different characteristics of child/adolescent and adult cAVMs suggest that they should be considered two distinct vascular disorders. The similar rates of radiosurgery-related complications and latency period bleeding in the two populations show that gamma knife radiosurgery does not expose young patients to a higher risk of sequelae than that for older patients

Use of 3.0-T MRI for Stereotactic Radiosurgery Planning for Treatment of Brain Metastases: A Single-Institution Retrospective Review

International Nuclear Information System (INIS)

Saconn, Paul A.; Shaw, Edward G.; Chan, Michael D.; Squire, Sarah E.; Johnson, Annette J.; McMullen, Kevin P.; Tatter, Stephen B.; Ellis, Thomas L.; Lovato, James; Bourland, J. Daniel; Ekstrand, Kenneth E.; DeGuzman, Allan F.; Munley, Michael T.

2010-01-01

Purpose: To investigate the efficacy of 3.0-T magnetic resonance imaging (MRI) for detecting brain metastases for stereotactic radiosurgery (SRS) planning. Methods and Materials: All adult patients scheduled for SRS treatment for brain metastases at our institution between October 2005 and January 2008 were eligible for analysis. All patients underwent radiosurgery treatment planning 3.0-T MRI on the day of scheduled radiosurgery and a diagnostic 1.5-T MRI in the days or weeks prior to radiosurgery for comparison. Both scans were interpreted by neuroradiologists who reported their findings in the radiology reports. We performed a retrospective review of the radiology reports to determine the number of brain metastases identified using each MRI system. Results: Of 254 patients scheduled for treatment from October 2005 to January 2008, 138 patients had radiology reports that explicitly described the number of metastases identified on both scans. With a median interval of 17 days (range, 1-82) between scans, the number of metastases detected using 1.5-T MRI system ranged from 1 to 5 and from 1 to 8 using the 3.0 T-MRI system. Twenty-two percent of patients were found to have a greater number of metastases with the 3.0 T-MRI system. The difference in number of metastases detected between the two scans for the entire cohort ranged from 0 to 6. Neither histology (p = 0.52 by chi-sq test) nor time between scans (p = 0.62 by linear regression) were significantly associated with the difference in number of metastases between scans. Conclusions: The 3.0-T MRI system appears to be superior to a 1.5-T MRI system for detecting brain metastases, which may have significant implications in determining the appropriate treatment modality. Our findings suggest the need for a prospectively designed study to further evaluate the use of a 3.0 T-MRI system for stereotactic radiosurgery planning in the treatment of brain metastases.

TU-H-CAMPUS-TeP1-03: Magnetically Focused Proton Irradiation of Small Volume Radiosurgery Targets

Energy Technology Data Exchange (ETDEWEB)

McAuley, GA; Slater, JM [Loma Linda University, Loma Linda, CA (United States); Wroe, AJ [Loma Linda University, Loma Linda, CA (United States); Loma Linda University Medical Center, Loma Linda, CA (United States)

2016-06-15

Purpose: To investigate the use of magnetic focusing for small volume proton radiosurgery targets using a triplet combination of quadrupole rare earth permanent magnet Halbach cylinder assemblies Methods: Fourteen quadrupole magnets consisting of 24 segments of radiation hard samarium-cobalt adhered into k=3 Halbach cylinders with various field gradients (100 to 250 T/m) were designed and manufactured. Triplet combinations of the magnets were placed on a positioning track on our Gantry 1 treatment table. Unmodulated 127 MeV proton beams with initial diameters of 3 to 20 mm were delivered to a water tank using single-stage scattering. Depth and transverse dose distributions were measured using a PTW PR60020 diode detector and EBT3 film, respectively. This data was compared with unfocused passively collimated beams. Monte Carlo simulations were also performed - both for comparison with experimental data and to further investigate the potential of triplet magnetic focusing. Results: Experimental results using 150 T/m gradient magnets and 15 to 20 mm initial diameter beams show peak to entrance dose ratios that are ∼ 43 to 48 % larger compared with spot size matched 8 mm collimated beams (ie, transverse profile full-widths at 90% maximum dose match within 0.5 mm of focused beams). In addition, the focusing beams were ∼ 3 to 4.4 times more efficient per MU in dose to target delivery. Additional results using different magnet combinations will also be presented. Conclusion: Our results suggest that triplet magnetic focusing could reduce entrance dose and beam number while delivering dose to small (∼≤ 10 mm diameter) radiosurgery targets in less time compared to unfocused beams. Immediate clinical applications include those associated with proton radiosurgery and functional radiosurgery of the brain and spine, however other treatment sites can be also envisioned. This project was sponsored with funding from the Department of Defense (DOD# W81XWH-BAA-10-1).

SU-E-T-446: Evaluation of the Dosimetric Properties of a Diode Detector to Proton Radiosurgery

Energy Technology Data Exchange (ETDEWEB)

Teran, A [Loma Linda University Medical Center, Loma Linda, CA (United States); San Diego State University, San Diego, CA (United States); McAuley, G; Slater, J M [Loma Linda University, Loma Linda, CA (United States); Slater, J D; Wroe, A [Loma Linda University Medical Center, Loma Linda, CA (United States)

2014-06-01

Purpose: To test the PTW PR60020 proton dosimetry diode in radiation fields relevant to proton radiosurgery applications and evaluate its suitability as a high resolution, real time dosimetry device. Methods: Data was collected using our standard nominal radiosurgery energies of 126 MeV and 155 MeV through a single stage scattering system, corresponding to a range of 9.7 and 15 cm in water respectively. Various beam modulations were tested as part of this study. Depth dose and beam profile measurements were completed with the PTW PR60020 dosimetry diode with comparative measurements using a PTW Markus ionization chamber and EBT2 Gafchromic film. Monte Carlo simulations were also completed for comparison. Results: The single 1 mm{sup 2} by 20 μm thick sensitive volume allowed for high spatial resolution measurements while maintaining sufficient sensitive volume to ensure that measurements could be completed without excessive beam delivery. Depth dose profiles exhibited negligible LET dependence which typically impacts film and other solid state dosimetry devices, while beam ranges measured with the PTW diode were within 1 mm of ion chamber data. In an edge on arrangement beam profiles were also measured within 0.5 mm full-width at half-maximum at various depths as compared to film and simulation data. Conclusion: The PTW PR60020 proved to be a very useful radiation metrology apparatus for proton radiosurgery applications. Its waterproof and rugged construction allowed for easy deployment in phantoms or water tanks that are commonly used in proton radiosurgery QA. Dosimetrically, the diode exhibited negligible LET dependence as a function of depth, while in edge on arrangement to the incident proton beam it facilitated the measurement of beam profiles with a spatial resolution comparable to both Monte Carlo and film measurements. This project was sponsored in part by funding from the Department of Defense (DOD# W81XWH-BAA-10-1)

Impact of spot size on plan quality of spot scanning proton radiosurgery for peripheral brain lesions

Energy Technology Data Exchange (ETDEWEB)

Wang, Dongxu, E-mail: dongxu-wang@uiowa.edu; Dirksen, Blake; Hyer, Daniel E.; Buatti, John M.; Sheybani, Arshin; Dinges, Eric; Felderman, Nicole; TenNapel, Mindi; Bayouth, John E.; Flynn, Ryan T. [Department of Radiation Oncology, University of Iowa, Iowa City, Iowa 52242 (United States)

2014-12-15

Purpose: To determine the plan quality of proton spot scanning (SS) radiosurgery as a function of spot size (in-air sigma) in comparison to x-ray radiosurgery for treating peripheral brain lesions. Methods: Single-field optimized (SFO) proton SS plans with sigma ranging from 1 to 8 mm, cone-based x-ray radiosurgery (Cone), and x-ray volumetric modulated arc therapy (VMAT) plans were generated for 11 patients. Plans were evaluated using secondary cancer risk and brain necrosis normal tissue complication probability (NTCP). Results: For all patients, secondary cancer is a negligible risk compared to brain necrosis NTCP. Secondary cancer risk was lower in proton SS plans than in photon plans regardless of spot size (p = 0.001). Brain necrosis NTCP increased monotonically from an average of 2.34/100 (range 0.42/100–4.49/100) to 6.05/100 (range 1.38/100–11.6/100) as sigma increased from 1 to 8 mm, compared to the average of 6.01/100 (range 0.82/100–11.5/100) for Cone and 5.22/100 (range 1.37/100–8.00/100) for VMAT. An in-air sigma less than 4.3 mm was required for proton SS plans to reduce NTCP over photon techniques for the cohort of patients studied with statistical significance (p = 0.0186). Proton SS plans with in-air sigma larger than 7.1 mm had significantly greater brain necrosis NTCP than photon techniques (p = 0.0322). Conclusions: For treating peripheral brain lesions—where proton therapy would be expected to have the greatest depth-dose advantage over photon therapy—the lateral penumbra strongly impacts the SS plan quality relative to photon techniques: proton beamlet sigma at patient surface must be small (<7.1 mm for three-beam single-field optimized SS plans) in order to achieve comparable or smaller brain necrosis NTCP relative to photon radiosurgery techniques. Achieving such small in-air sigma values at low energy (<70 MeV) is a major technological challenge in commercially available proton therapy systems.

Impact of spot size on plan quality of spot scanning proton radiosurgery for peripheral brain lesions

International Nuclear Information System (INIS)

Wang, Dongxu; Dirksen, Blake; Hyer, Daniel E.; Buatti, John M.; Sheybani, Arshin; Dinges, Eric; Felderman, Nicole; TenNapel, Mindi; Bayouth, John E.; Flynn, Ryan T.

2014-01-01

Purpose: To determine the plan quality of proton spot scanning (SS) radiosurgery as a function of spot size (in-air sigma) in comparison to x-ray radiosurgery for treating peripheral brain lesions. Methods: Single-field optimized (SFO) proton SS plans with sigma ranging from 1 to 8 mm, cone-based x-ray radiosurgery (Cone), and x-ray volumetric modulated arc therapy (VMAT) plans were generated for 11 patients. Plans were evaluated using secondary cancer risk and brain necrosis normal tissue complication probability (NTCP). Results: For all patients, secondary cancer is a negligible risk compared to brain necrosis NTCP. Secondary cancer risk was lower in proton SS plans than in photon plans regardless of spot size (p = 0.001). Brain necrosis NTCP increased monotonically from an average of 2.34/100 (range 0.42/100–4.49/100) to 6.05/100 (range 1.38/100–11.6/100) as sigma increased from 1 to 8 mm, compared to the average of 6.01/100 (range 0.82/100–11.5/100) for Cone and 5.22/100 (range 1.37/100–8.00/100) for VMAT. An in-air sigma less than 4.3 mm was required for proton SS plans to reduce NTCP over photon techniques for the cohort of patients studied with statistical significance (p = 0.0186). Proton SS plans with in-air sigma larger than 7.1 mm had significantly greater brain necrosis NTCP than photon techniques (p = 0.0322). Conclusions: For treating peripheral brain lesions—where proton therapy would be expected to have the greatest depth-dose advantage over photon therapy—the lateral penumbra strongly impacts the SS plan quality relative to photon techniques: proton beamlet sigma at patient surface must be small (<7.1 mm for three-beam single-field optimized SS plans) in order to achieve comparable or smaller brain necrosis NTCP relative to photon radiosurgery techniques. Achieving such small in-air sigma values at low energy (<70 MeV) is a major technological challenge in commercially available proton therapy systems

Stereotactic Radiosurgery for Intracranial Tumors : Early Experience with Linear Accelerator

Energy Technology Data Exchange (ETDEWEB)

Shu, Chang Ok; Chung, Sang Sup; Chu, Sung Sil; Kim, Young Soo; Yoon, Do Heum; Kim, Sun Ho; Loh, John Juhn; Kim, Gwi Eon [Yonsei University College of Medicine, Seoul (Korea, Republic of)

1992-06-15

Between August 1988 and December 1991, 24 patients with intracranial tumors were treated with stereotactic radiosurgery(RS) using a 10 MV linear accelerator at Severance Hospital, Yonsei University College of Medicine. There were 5 meningiomas, 3 craniopharyngiomas, 9 glial tumors, 2 solitary metastases, 2 acoustic neurinomas, 2 pineal tumors, and 1 non-Hodgkin Iymphoma. Ten patients were treated as primary treatment after diagnosis with stereotactic biopsy or neuroimaging study. Nine patients underwent RS for post-op. residual tumors and three patients as a salvage treatment for recurrence after external irradiation. Two patients received RS as a boost followed by fractionated conventional radiotherapy. Among sixteen patients who were followed more than 6 months with neuroimage, seven patients (2 meningiomas, 4 benign glial tumors, one non-Hodgkin lymphoma) showed complete response on neuroimage after RS and nine patients showed decreased tumor size. There was no acute treatment related side reaction. Late complications include three patients with symptomatic peritumoral braid edema and one craniopharyngioma with optic chiasmal injury. Through this early experience, we conclude that stereotactically directed single high doses of irradiation to the small intracranial tumors is effective for tumor control. However, in order to define the role of radiosurgery in the management of intracranial tumors, we should get the long-term results available to demonstrate the benefits versus potential complications of this therapeutic modality.

Single-fraction vs. fractionated linac-based stereotactic radiosurgery for vestibular schwannoma: a single-institution study

NARCIS (Netherlands)

Meijer, O. W. M.; Vandertop, W. P.; Baayen, J. C.; Slotman, B. J.

2003-01-01

PURPOSE: In this single-institution trial, we investigated whether fractionated stereotactic radiation therapy is superior to single-fraction linac-based radiosurgery with respect to treatment-related toxicity and local control in patients with vestibular schwannoma. METHODS AND MATERIALS: All 129

Geometrical and dosimetrical characterization of the photon source using a micro-multileaf collimator for stereotactic radiosurgery

Energy Technology Data Exchange (ETDEWEB)

Treuer, H [Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne (Germany); Hoevels, M [Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne (Germany); Luyken, K [Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne (Germany); Hunsche, S [Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne (Germany); Kocher, M [Department of Radiotherapy, University of Cologne, Cologne (Germany); Mueller, R-P [Department of Radiotherapy, University of Cologne, Cologne (Germany); Sturm, V [Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne (Germany)

2003-08-07

A micro-multileaf collimator ({mu}MLC) for stereotactic radiosurgery is used for determination of the spatial intensity distribution of the photon source of a linear accelerator. The method is based on grid field dose measurements using film dosimetry and is easy to perform. Since the {mu}MLC does not allow 'direct' imaging of the photon source, special software has been developed to analyse grid field measurements. Besides the source-density function, grid field analysis yields the position of the focal spot in the room laser coordinate system of the linear accelerator and the position of the treatment head rotation axis and the inclination angle of the leaf bank. Thus the method can be used for base dosimetry and for quality assurance in radiosurgery using a {mu}MLC.

{sup 10}B-augmented fast neutron radiosurgery for brain tumor treatment

Energy Technology Data Exchange (ETDEWEB)

Wang, C.; Chen, J. [Georgia Institute of Technology, Atlanta, GA (United States); Halpern, D.; Moore, C. [Isotron Inc., Alpharetta, GA (United States)

2000-10-01

We have investigated a new {sup 10}B-enhanced fast neutron treatment modality based on a concept similar to the x-ray radiosurgery or gamma knife. The results from our proof-of-principle Monte Carlo calculations clearly indicate that the dose-volume-histogram (DVH) of a 5-cm-deep tumor treated with multiple converging neutron beams is superior to that treated with a single broad neutron beam. To find out if the idea of neutron radiosurgery is practical, we have designed a small neutron beam based on 1-mA of 7-MeV deuterons bombarding a thick beryllium target, i.e. via Be(d,n) reactions. Such a deuteron beam is already achievable based on the existing accelerator technology, and it is also inexpensive. The Monte Carlo results show that the Be(d,n)-based facility produces an average dose rate of 1.9 Gy min{sup -1} in the tumor volume. For a typical tumor dose of 20 Gy, the treatment time would be 10.5 minutes. The results also show that the preferential loading of 100 ppm of {sup 10}B will produce in average an additional 8% of dose to tumor cells via {sup 10}B(n,{alpha}){sup 7}Li reactions. (author)

Analytic characterization of linear accelerator radiosurgery dose distributions for fast optimization

International Nuclear Information System (INIS)

Meeks, S.L.; Buatti, J.M.; Eyster, B.; Kendrick, L.A.

1999-01-01

Linear accelerator (linac) radiosurgery utilizes non-coplanar arc therapy delivered through circular collimators. Generally, spherically symmetric arc sets are used, resulting in nominally spherical dose distributions. Various treatment planning parameters may be manipulated to provide dose conformation to irregular lesions. Iterative manipulation of these variables can be a difficult and time-consuming task, because (a) understanding the effect of these parameters is complicated and (b) three-dimensional (3D) dose calculations are computationally expensive. This manipulation can be simplified, however, because the prescription isodose surface for all single isocentre distributions can be approximated by conic sections. In this study, the effects of treatment planning parameter manipulation on the dimensions of the treatment isodose surface were determined empirically. These dimensions were then fitted to analytic functions, assuming that the dose distributions were characterized as conic sections. These analytic functions allowed real-time approximation of the 3D isodose surface. Iterative plan optimization, either manual or automated, is achieved more efficiently using this real time approximation of the dose matrix. Subsequent to iterative plan optimization, the analytic function is related back to the appropriate plan parameters, and the dose distribution is determined using conventional dosimetry calculations. This provides a pseudo-inverse approach to radiosurgery optimization, based solely on geometric considerations. (author)

Frame and frameless linear accelerator-based radiosurgery for idiopathic trigeminal neuralgia.

Science.gov (United States)

Chen, Allan Y; Hsieh, Yen; McNair, Steffanie; Li, Qijuan; Xu, Kevin Y; Pappas, Conrad

2015-01-01

We report outcome of linear accelerator (Linac)-based stereotactic radiosurgery (SRS) for trigeminal neuralgia (TGN) utilizing rigid head frame (RF) and facemask (FM) immobilization.Method: From November 2008 to October 2012, 48 patients with idiopathic TGN underwent primary SRS by a dedicated Linac. RF immobilization was utilized for 34 patients, and frameless image-guided radiosurgery (IGRS) with FM immobilization was performed in 14 patients. Treatment outcome was assessed by patient interviews with a 7-item questionnaire. Sub-millimeter targeting accuracy (0.71±0.31 mm) was recorded for frameless IGRS by a novel hidden-target phantom method. With a follow-up of 26 months, significant pain relief was recorded in 43 (89%) patients, including 26 (54%) complete and 17 (35%) partial responses; with a significant reduction of 2.4±1.3 points ( p < 0.01) on the 5-point Barrow Neurological Institute pain scale. No significant pain relief difference ( p = 0.23) was detected between patients immobilized by RF and FM. Notable pin site problems were reported in 9 (26%) of 34 patients immobilized by RF. Frameless IGRS with FM immobilization is more patient friendly and can achieve as excellent treatment outcome as with RF immobilization for idiopathic TGN.

Technical Note: Dose gradients and prescription isodose in orthovoltage stereotactic radiosurgery

International Nuclear Information System (INIS)

Fagerstrom, Jessica M.; Bender, Edward T.; Culberson, Wesley S.

2016-01-01

Purpose: The purpose of this work is to examine the trade-off between prescription isodose and dose gradients in orthovoltage stereotactic radiosurgery. Methods: Point energy deposition kernels (EDKs) describing photon and electron transport were calculated using Monte Carlo methods. EDKs were generated from 10  to 250 keV, in 10 keV increments. The EDKs were converted to pencil beam kernels and used to calculate dose profiles through isocenter from a 4π isotropic delivery from all angles of circularly collimated beams. Monoenergetic beams and an orthovoltage polyenergetic spectrum were analyzed. The dose gradient index (DGI) is the ratio of the 50% prescription isodose volume to the 100% prescription isodose volume and represents a metric by which dose gradients in stereotactic radiosurgery (SRS) may be evaluated. Results: Using the 4π dose profiles calculated using pencil beam kernels, the relationship between DGI and prescription isodose was examined for circular cones ranging from 4 to 18 mm in diameter and monoenergetic photon beams with energies ranging from 20 to 250 keV. Values were found to exist for prescription isodose that optimize DGI. Conclusions: The relationship between DGI and prescription isodose was found to be dependent on both field size and energy. Examining this trade-off is an important consideration for designing optimal SRS systems.

Clinical Outcome in Gamma Knife Radiosurgery for Metastatic Brain Tumors from the Primary Breast Cancer : Prognostic Factors in Local Treatment Failure and Survival

OpenAIRE

Choi, Seung Won; Kwon, Do Hoon; Kim, Chang Jin

2013-01-01

Objective Brain metastases in primary breast cancer patients are considerable sources of morbidity and mortality. Gamma knife radiosurgery (GKRS) has gained popularity as an up-front therapy in treating such metastases over traditional radiation therapy due to better neurocognitive function preservation. The aim of this study was to clarify the prognostic factors for local tumor control and survival in radiosurgery for brain metastases from primary breast cancer. Methods From March 2001 to Ma...

Changes in the peritumoral hypoperfusion area immediately after radiosurgery for metastatic brain tumor. Analysis using 3D-SPECT

Energy Technology Data Exchange (ETDEWEB)

Nemoto, Masaaki [Toho Univ., Tokyo (Japan). School of Medicine

2001-09-01

Sixteen patients with single metastatic brain tumor underwent SPECT using N-isopropyl-p-({sup 123}I) iodoamphetamine ({sup 123}I-IMP) before and after radiosurgery. Influence of treatment was evaluated using three-dimensional SPECT images, threshold-voxel graphs and changes in the volume of the peritumoral hypoperfusion area. A three-detector type scanner, the PRISM3000, was also used. SPECT scanning was performed for 30 minutes after intravenous administration of {sup 123}I-IMP with sequential scans every 1 minutes. The data obtained 16-30 minutes after administration were processed using a low-pass ramp filter, and three-dimensional SPECT images were constructed from these data using the Application Visualization System (AVS). Furthermore, a threshold-voxel graph was plotted and the volume of the peritumoral hypoperfusion area was calculated. SPECT was performed before radiosurgery, and 1 day, 1 week, and 1 month after, and these data were compared. Three-dimensional SPECT presented the area of peritumoral hypoperfusion as a deficit image and changes were evaluated visually. Threshold-voxel graphs were evaluated as follows: changes in voxels with a threshold of 40-50% indicated a hypoperfusion area, and changes in voxels with a threshold of 70-95% indicated a hyperperfusion area in the tumor side hemisphere. The volume of the peritumoral hypoperfusion area was calculated using the voxel difference between the tumor side and normal hemispheres. Our results showed that the peritumoral hypoperfusion area gradually decreased after an initial first-day increase following radiosurgery. Visual three-dimensional SPECT allowed us to monitor both the volume of the peritumoral hypoperfusion area of metastatic brain tumors after radiosurgery by means of a threshold-voxel graph and changes in the peritumoral hypoperfusion area. (author)

A New Approach with Combined Stereotactic Trans-multiarc Beams for Radiosurgery Based on the Linear Accelerator : Photon Knife

International Nuclear Information System (INIS)

Choi, Tae Jin; Kim, Jin Hee; Kim, Ok Bae

1996-01-01

Purpose : To get an acute steepness of dose gradients at outside the target volume in intracranial lesion and a less limitation of beam selection avoiding the high dose at normal brain tissue, this Photon Knife Radiosurgery System was developed in order to provide the three-dimensional dose distribution through the reconstruction of CT scan and the combined stereotactic tranmultiarc beam mode based on linear accelerator photon beam. Methods and Materials : This stereotactic radiosurgery, Photon Knife based on linear accelerator photon beam was provided the non-coplanar multiarc and trans-multiarc irradiations. The stereotactic trans-multiarc beam mode can be obtained from the patient position in decubitus. This study has provided the 3-dimensional isodose curve and anatomical structures with the surface rendering technique. Results : In this study, it shows that the dose distributions of stereotactic beam mode are significantly depended on the selected couch and gantry angle in same collimator size. Practical dose distribution of combined stereotactic trans-multiarc beam has shown a more small rim thickness than that of the non-coplanar multiarc beam mode in axial, sagittal and coronal plane in our study. 3-Dimensional dose line displayed with surface rendering of irregular target shape is helpful to determine the target dose and to predict the prognosis in follow-up radiosurgery. Conclusion : 3-Dimensional dose line displayed with surface rendering of irregular target shape is essential in stereotactic radiosurgery. This combined stereotactic trans-multiarc beam has shown a less limitation of the selection couch and gantry beam angles for the target surrounding critical organs. It has shown that the dose distribution of combined trans-multiarc beam greatly depended on the couch and gantry angles. In our experiments. the absorbed dose has been decreased to 27 % /mm in maximum at the interval of 50% to 80% of isodose line

Retrospective analysis of linac-based radiosurgery for arteriovenous malformations and testing of the Flickinger formula in predicting radiation injury

International Nuclear Information System (INIS)

Cetin, I.A.; Marmara Univ., Ustkaynarca/Pendik; Ates, R.; Dhaens, J.; Storme, G.

2012-01-01

Background and purpose: The aim of the study was to validate the use of linac-based radiosurgery in arteriovenous malformation (AVM) patients and to predict complications using an integrated logistic formula (ILF) in comparison with clinical outcomes. Patients and methods: The results of radiosurgery in 92 AVM patients were examined. All patients were treated with linac-based radiosurgery. Of these, 70 patients were followed for 12-45 months (median, 24 months) and were analyzed. The treated volume varied from 0.09 to 26.95 cm 3 (median, 2.3 cm 3 ) and the median marginal dose was 20 Gy (range, 10.4-22). The median 12-Gy volume was 9.94 cm 3 (range, 0.74-60.09 cm 3 ). Patients and lesion characteristics potentially affecting nidus obliteration and excellent outcome were evaluated by performing a log-rank test and univariate and multivariate analyses. The risk for radiation injury (RRI) was calculated with an integrated logistic formula. The predictive power of the RRI was assessed by calculating the area under the receiver operating characteristic (ROC) curve. Results: Follow-up magnetic resonance (MR) angiography revealed complete AVM obliteration in 56 of 70 patients. The MR angiography confirmed an obliteration rate of 80%. The annual hemorrhage rate was 1.4% for the first 2 years after radiosurgery and 0% thereafter. The number of patients with an excellent outcome was 48 (68%). Factors associated with better obliteration were higher radiation dose to the lesion margins [12-Gy volume (V12) > 10 cm 3 ], small volume, and a Pollock-Flickinger score less than 1.49; those predicting excellent outcomes were V12 3 , small volume, and Pollock-Flickinger score less than 1.49, as determined by multivariate analyses. Factors associated with radiation injury were V12 > 10 cm 3 (p=0.03) and volume greater than 2 cm 3 (p=0.001), as determined by a univariate analysis. The analyses showed an ROC of 0.66. Conclusion: These data suggest that linac-based radiosurgery is

An analysis of the effects of smoking and other cardiovascular risk factors on obliteration rates after arteriovenous malformation radiosurgery

International Nuclear Information System (INIS)

Bhatnagar, Ajay; Flickinger, John C.; Kondziolka, Douglas; Niranjan, Ajay; Lunsford, L. Dade

2001-01-01

Purpose: To assess the relationships of smoking and other cardiovascular disease risk factors (hypertension, diabetes, hypercholesterolemia, and gender) to rates of radiosurgery-induced obliteration of arteriovenous malformations (AVM). Methods and Materials: We evaluated follow-up imaging and clinical data in 329 AVM patients who received gamma knife radiosurgery at the University of Pittsburgh between 1987 and 1994. There were 113 smokers, 29 hypertensives, 5 diabetics, 4 hypercholesterolemics, 159 male patients, and 170 female patients. All patients had regular clinical or imaging follow-up for a minimum of 3 years after radiosurgery. Results: Multivariate analysis showed that smoking had no effect on AVM obliteration (p>0.43). Hypertension, diabetes, and hypercholesterolemia had no discernible effect on AVM obliteration in this study (p>0.78). However, females aged 12-49 had a statistically significant lower in-field obliteration rate than males (78% vs. 89%, p=0.0102). Conclusion: Smoking has no effect on AVM obliteration. Hypertension, diabetes, and hypercholesterolemia had no discernible effect in this study. Further study is needed to establish whether estrogen has a vascular protective effect that could partially limit radiosurgical AVM obliteration, as suggested by this study

Late clinical and radiological complications of stereotactical radiosurgery of arteriovenous malformations of the brain

Energy Technology Data Exchange (ETDEWEB)

Parkhutik, Vera [Hospital Universitario la Fe, Department of Neurology, Valencia (Spain); Universidad Autonoma de Barcelona, PhD Program of the Department of Medicine, Barcelona (Spain); Lago, Aida; Vazquez, Juan Francisco; Tembl, Jose Ignacio [Hospital Universitario la Fe, Department of Neurology, Valencia (Spain); Aparici, Fernando; Guillen, Lourdes; Mainar, Esperanza; Vazquez, Victor [Hospital Universitario la Fe, Department of Neuroradiology, Valencia (Spain)

2013-04-15

Post-radiation injury of patients with brain arteriovenous malformations (AVM) include blood-brain barrier breakdown (BBBB), edema, and necrosis. Prevalence, clinical relevance, and response to treatment are poorly known. We present a series of consecutive brain AVM treated with stereotactic radiosurgery describing the appearance of radiation injury and clinical complications. Consecutive patients with annual clinical and radiological follow-up (median length 63 months). Edema and BBBB were classified in four groups (minimal, perilesional, moderate, or severe), and noted together with necrosis. Clinical symptoms of interest were intracranial hypertension, new neurological deficits, new seizures, and brain hemorrhages. One hundred two cases, median age 34 years, 52 % male. Median irradiated volume 3.8 cc, dose to the margin of the nidus 18.5 Gy. Nineteen patients underwent a second radiosurgery. Only 42.2 % patients remained free from radiation injury. Edema was found in 43.1 %, blood-brain barrier breakdown in 20.6 %, necrosis in 6.9 %. Major injury (moderate or severe edema, moderate or severe BBBB, or necrosis) was found in 20 of 102 patients (19.6 %). AVM diameter >3 cm and second radiosurgery were independent predictors. Time to the worst imaging was 60 months. Patients with major radiation injury had a hazard ratio for appearance of focal deficits of 7.042 (p = 0.04), of intracranial hypertension 2.857 (p = 0.025), hemorrhage into occluded nidus 9.009 (p = 0.079), appearance of new seizures not significant. Major radiation injury is frequent and increases the risk of neurological complications. Its late appearance implies that current follow-up protocols need to be extended in time. (orig.)

Radiosurgery for Craniopharyngioma

International Nuclear Information System (INIS)

Niranjan, Ajay; Kano, Hideyuki; Mathieu, David; Kondziolka, Douglas; Flickinger, John C.; Lunsford, L. Dade

2010-01-01

Purpose: To analyze the outcomes of gamma knife stereotactic radiosurgery (SRS) for residual or recurrent craniopharyngiomas and evaluate the factors that optimized the tumor control rates. Methods and Materials: A total of 46 patients with craniopharyngiomas underwent 51 SRS procedures at University of Pittsburgh between 1988 and 2007. The median tumor volume was 1.0 cm 3 (range, 0.07-8.0). The median prescription dose delivered to the tumor margin was 13.0 Gy (range, 9-20). The median maximal dose was 26.0 Gy (range, 20-50). The mean follow-up time was 62.2 months (range, 12-232). Results: The overall survival rate after SRS was 97.1% at 5 years. The 3- and 5-year progression-free survival rates (solid tumor control) were both 91.6%. The overall local control rate (for both solid tumor and cyst control) was 91%, 81%, and 68% at 1, 3, and 5 years, respectively. No patients with normal pituitary function developed hypopopituitarism after SRS. Two patients developed homonymous hemianopsia owing to tumor progression after SRS. Among the factors examined, complete radiosurgical coverage was a significant favorable prognostic factor. Conclusion: SRS is a safe and effective minimally invasive option for the management of residual or recurrent craniopharyngiomas. Complete radiosurgical coverage of the tumor was associated with better tumor control.

Plug pattern optimization for gamma knife radiosurgery treatment planning

International Nuclear Information System (INIS)

Zhang Pengpeng; Wu, Jackie; Dean, David; Xing Lei; Xue Jinyue; Maciunas, Robert; Sibata, Claudio

2003-01-01

Purpose: To develop a novel dose optimization algorithm for improving the sparing of critical structures during gamma knife radiosurgery by shaping the plug pattern of each individual shot. Method and Materials: We first use a geometric information (medial axis) aided guided evolutionary simulated annealing (GESA) optimization algorithm to determine the number of shots and isocenter location, size, and weight of each shot. Then we create a plug quality score system that checks the dose contribution to the volume of interest by each plug in the treatment plan. A positive score implies that the corresponding source could be open to improve tumor coverage, whereas a negative score means the source could be blocked for the purpose of sparing normal and critical structures. The plug pattern is then optimized via the GESA algorithm that is integrated with this score system. Weight and position of each shot are also tuned in this procedure. Results: An acoustic tumor case is used to evaluate our algorithm. Compared to the treatment plan generated without plug patterns, adding an optimized plug pattern into the treatment planning process boosts tumor coverage index from 95.1% to 97.2%, reduces RTOG conformity index from 1.279 to 1.167, lowers Paddick's index from 1.34 to 1.20, and trims the critical structure receiving more than 30% maximum dose from 16 mm 3 to 6 mm 3 . Conclusions: Automated GESA-based plug pattern optimization of gamma knife radiosurgery frees the treatment planning team from the manual forward planning procedure and provides an optimal treatment plan

ASSOCIATION BETWEEN COMPUTED TOMOGRAPHIC CHARACTERISTICS AND FRACTURES FOLLOWING STEREOTACTIC RADIOSURGERY IN DOGS WITH APPENDICULAR OSTEOSARCOMA.

Science.gov (United States)

Kubicek, Lyndsay; Vanderhart, Daniel; Wirth, Kimberly; An, Qi; Chang, Myron; Farese, James; Bova, Francis; Sudhyadhom, Atchar; Kow, Kelvin; Bacon, Nicholas J; Milner, Rowan

2016-05-01

The objective of this observational, descriptive, retrospective study was to report CT characteristics associated with fractures following stereotactic radiosurgery in canine patients with appendicular osteosarcoma. Medical records (1999 and 2012) of dogs that had a diagnosis of appendicular osteosarcoma and undergone stereotactic radiosurgery were reviewed. Dogs were included in the study if they had undergone stereotactic radiosurgery for an aggressive bone lesion with follow-up information regarding fracture status, toxicity, and date and cause of death. Computed tomography details, staging, chemotherapy, toxicity, fracture status and survival data were recorded. Overall median survival time (MST) and fracture rates of treated dogs were calculated. CT characteristics were evaluated for association with time to fracture. Forty-six dogs met inclusion criteria. The median overall survival time was 9.7 months (95% CI: 6.9-14.3 months). The fracture-free rates at 3, 6, and 9 months were 73%, 44%, and 38% (95% CI: 60-86%, 29-60%, and 22-54%), respectively. The region of bone affected was significantly associated with time to fracture. The median time to fracture was 4.2 months in dogs with subchondral bone involvement and 16.3 months in dogs without subchondral bone involvement (P-value = 0.027, log-rank test). Acute and late skin effects were present in 58% and 16% of patients, respectively. Findings demonstrated a need for improved patient selection for this procedure, which can be aided by CT-based prognostic factors to predict the likelihood of fracture. © 2016 American College of Veterinary Radiology.

Radiosurgery alone for 5 or more brain metastases: expert opinion survey.

Science.gov (United States)

Knisely, Jonathan P S; Yamamoto, Masaaki; Gross, Cary P; Castrucci, William A; Jokura, Hidefumi; Chiang, Veronica L S

2010-12-01

Oligometastatic brain metastases may be treated with stereotactic radiosurgery (SRS) alone, but no consensus exists as to when SRS alone would be appropriate. A survey was conducted at 2 radiosurgery meetings to determine which factors SRS practitioners emphasize in recommending SRS alone, and what physician characteristics are associated with recommending SRS alone for ≥ 5 metastases. All physicians attending the 8th Biennial Congress and Exhibition of the International Stereotactic Radiosurgery Society in June 2007 and the 18th Annual Meeting of the Japanese Society of Stereotactic Radiosurgery in July 2009 were asked to complete a questionnaire ranking 14 clinical factors on a 5-point Likert-type scale (ranging from 1 = not important to 5 = very important) to determine how much each factor might influence a decision to recommend SRS alone for brain metastases. Results were condensed into a single dichotomous outcome variable of "influential" (4-5) versus "not influential" (1-3). Respondents were also asked to complete the statement: "In general, a reasonable number of brain metastases treatable by SRS alone would be, at most, ___." The characteristics of physicians willing to recommend SRS alone for ≥ 5 metastases were assessed. Chi-square was used for univariate analysis, and logistic regression for multivariate analysis. The final study sample included 95 Gamma Knife and LINAC-using respondents (54% Gamma Knife users) in San Francisco and 54 in Sendai (48% Gamma Knife users). More than 70% at each meeting had ≥ 5 years experience with SRS. Sixty-five percent in San Francisco and 83% in Sendai treated ≥ 30 cases annually with SRS. The highest number of metastases considered reasonable to treat with SRS alone in both surveys was 50. In San Francisco, the mean and median numbers of metastases considered reasonable to treat with SRS alone were 6.7 and 5, while in Sendai they were 11 and 10. In the San Francisco sample, the clinical factors identified to be

Repeat Gamma-Knife Radiosurgery for Refractory or Recurrent Trigeminal Neuralgia with Consideration About the Optimal Second Dose.

Science.gov (United States)

Park, Seong-Cheol; Kwon, Do Hoon; Lee, Do Hee; Lee, Jung Kyo

2016-02-01

To investigate adequate radiation doses for repeat Gamma Knife radiosurgery (GKS) for trigeminal neuralgia in our series and meta-analysis. Fourteen patients treated by ipsilateral repeat GKS for trigeminal neuralgia were included. Median age of patients was 65 years (range, 28-78), the median target dose, 140-180). Patients were followed a median of 10.8 months (range, 1-151) after the second gamma-knife surgery. Brainstem dose analysis and vote-counting meta-analysis of 19 studies were performed. After the second gamma-knife radiosurgeries, pain was relieved effectively in 12 patients (86%; Barrow Neurological Institute Pain Intensity Score I-III). Post-gamma-knife radiosurgery trigeminal nerve deficits were mild in 5 patients. No serious anesthesia dolorosa was occurred. The second GKS radiation dose ≤ 60 Gy was significantly associated with worse pain control outcome (P = 0.018 in our series, permutation analysis of variance, and P = 0.009 in the meta-analysis, 2-tailed Fisher's exact test). Cumulative dose ≤ 140-150 Gy was significantly associated with poor pain control outcome (P = 0.033 in our series and P = 0.013 in the meta-analysis, 2-tailed Fisher's exact test). A cumulative brainstem edge dose >12 Gy tended to be associated with trigeminal nerve deficit (P = 0.077). Our study suggests that the second GKS dose is a potentially important factor. Copyright © 2016 Elsevier Inc. All rights reserved.

Adverse radiation effect after stereotactic radiosurgery for brain metastases : incidence, time course, and risk factors

NARCIS (Netherlands)

Sneed, Penny K.; Mendez, Joe; Vemer-van den Hoek, Johanna; Seymour, Zachary A.; Ma, Lijun; Molinaro, Annette M.; Fogh, Shannon E.; Nakamura, Jean L.; McDermott, Michael W.

OBJECT The authors sought to determine the incidence, time course, and risk factors for overall adverse radiation effect (ARE) and symptomatic ARE after stereotactic radiosurgery (SRS) for brain metastases. METHODS All cases of brain metastases treated from 1998 through 2009 with Gamma Knife SRS at

Long-term quality of life and tumour control following gamma knife radiosurgery for vestibular schwannoma

DEFF Research Database (Denmark)

Wangerid, Theresa; Bartek, Jiri; Svensson, Mikael

2014-01-01

Gamma knife radiosurgery (GKRS) has for the last decades been an established treatment option for patients with small- or medium-sized vestibular schwannomas (VS), although little data is reported on long-term outcome regarding quality of life (QOL) and tumour control in this patient category...

Optimal technique of linear accelerator–based stereotactic radiosurgery for tumors adjacent to brainstem

International Nuclear Information System (INIS)

Chang, Chiou-Shiung; Hwang, Jing-Min; Tai, Po-An; Chang, You-Kang; Wang, Yu-Nong; Shih, Rompin; Chuang, Keh-Shih

2016-01-01

Stereotactic radiosurgery (SRS) is a well-established technique that is replacing whole-brain irradiation in the treatment of intracranial lesions, which leads to better preservation of brain functions, and therefore a better quality of life for the patient. There are several available forms of linear accelerator (LINAC)–based SRS, and the goal of the present study is to identify which of these techniques is best (as evaluated by dosimetric outcomes statistically) when the target is located adjacent to brainstem. We collected the records of 17 patients with lesions close to the brainstem who had previously been treated with single-fraction radiosurgery. In all, 5 different lesion catalogs were collected, and the patients were divided into 2 distance groups—1 consisting of 7 patients with a target-to-brainstem distance of less than 0.5 cm, and the other of 10 patients with a target-to-brainstem distance of ≥ 0.5 and < 1 cm. Comparison was then made among the following 3 types of LINAC-based radiosurgery: dynamic conformal arcs (DCA), intensity-modulated radiosurgery (IMRS), and volumetric modulated arc radiotherapy (VMAT). All techniques included multiple noncoplanar beams or arcs with or without intensity-modulated delivery. The volume of gross tumor volume (GTV) ranged from 0.2 cm 3 to 21.9 cm 3 . Regarding the dose homogeneity index (HI ICRU ) and conformity index (CI ICRU ) were without significant difference between techniques statistically. However, the average CI ICRU = 1.09 ± 0.56 achieved by VMAT was the best of the 3 techniques. Moreover, notable improvement in gradient index (GI) was observed when VMAT was used (0.74 ± 0.13), and this result was significantly better than those achieved by the 2 other techniques (p < 0.05). For V 4 Gy of brainstem, both VMAT (2.5%) and IMRS (2.7%) were significantly lower than DCA (4.9%), both at the p < 0.05 level. Regarding V 2 Gy of normal brain, VMAT plans had attained 6.4 ± 5%; this was significantly better

Extracranial Facial Nerve Schwannoma Treated by Hypo-fractionated CyberKnife Radiosurgery

OpenAIRE

Sasaki, Ayaka; Miyazaki, Shinichiro; Hori, Tomokatsu

2016-01-01

Facial nerve schwannoma is a rare intracranial tumor. Treatment for this benign tumor has been controversial. Here, we report a case of extracranial facial nerve schwannoma treated successfully by hypo-fractionated CyberKnife (Accuray, Sunnyvale, CA) radiosurgery?and discuss the efficacy of this treatment. A 34-year-old female noticed a swelling in her right mastoid process. The lesion enlarged over a seven-month period, and she experienced facial spasm on the right side. She was diagnosed wi...

Acceptance, commissioning and quality control in radiosurgery; Aceite, comissionamento e controle de qualidade em radiocirurgia

Energy Technology Data Exchange (ETDEWEB)

Toreti, Dalila Luzia

2009-07-01

Stereotactic Radiosurgery is a treatment technique that uses narrow beams of radiation focused with great accuracy in a small lesion. The introduction of micro multi leaf collimators (mMLC) allows this technique to reach a higher degree of dose conformation of the target lesion allowing a smaller irradiation of critical structures and normal tissues. This paper presents the results of the acceptance tests and commissioning of a Varian 6EX linear accelerator dedicated to radiosurgery associated with the BrainLab micro multi leaf collimator installed in the Hospital das Clinicas da Faculdade de Medicina da USP (HC-FMUSP) and establish feasible quality assurance program for the services that employ this special technique. The results of the acceptance tests were satisfactory and are willing with the specifications provided by the manufacturer and the commissioning tests were within the international recommendations. The tests and measures that are part of quality control process should be specific to each treatment unit, and the need, frequency and levels of tolerance.

SU-G-BRB-10: New Generation of High Frame-Rate and High Spatial-Resolution EPID QA System for Full-Body MLC-Based Robotic Radiosurgery

International Nuclear Information System (INIS)

Han, B; Xing, L; Wang, L

2016-01-01

Purpose: To systematically investigate an ultra-high spatial-resolution amorphous silicon flat-panel electronic portal imaging device (EPID) for MLC-based full-body robotic radiosurgery geometric and dosimetric quality assurance (QA). Methods: The high frame-rate and ultra-high spatial resolution EPID is an outstanding detector for measuring profiles, MLC-shaped radiosurgery field aperture verification, and small field dosimetry. A Monte Carlo based technique with a robotic linac specific response and calibration is developed to convert a raw EPID-measured image of a radiosurgery field into water-based dose distribution. The technique is applied to measure output factors and profiles for 6MV MLC-defined radiosurgery fields with various sizes ranging from 7.6mm×7.7mm to 100mm×100.1mm and the results are compared with the radiosurgery diode scan measurements in water tank. The EPID measured field sizes and the penumbra regions are analyzed to evaluate the MLC positioning accuracy. Results: For all MLC fields, the EPID measured output factors of MLC-shaped fields are in good agreement with the diode measurements. The mean output difference between the EPID and diode measurement is 0.05±0.87%. The max difference is −1.33% for 7.6mm×7.7mm field. The MLC field size derived from the EPID measurements are in good agreement comparing to the diode scan result. For crossline field sizes, the mean difference is −0.17mm±0.14mm with a maximum of −0.35mm for the 30.8mm×30.8mm field. For inline field sizes, the mean difference is +0.08mm±0.18mm with a maximum of +0.45mm for the 100mm×100.1mm field. The high resolution EPID is able to measure the whole radiation field, without the need to align the detector center perfectly at field center as diode or ion chamber measurement. The setup time is greatly reduced so that the whole process is possible for machine and patient-specific QA. Conclusion: The high spatial-resolution EPID is proved to be an accurate and efficient

Dosimetry and narrow X-ray beams, produced by particle linear accelerator for use in radiosurgery

International Nuclear Information System (INIS)

Campos, J.C.F.; Vizeu, D.M.

1987-01-01

The principal characteristics of dosimetry and narrow X-ray beams(4Mv) monitoring are investigated for use in estereotatic radiosurgery. An additional collimator system and a estereotatic system (Leksell type) are presented. Dosimetric parameters like tissue-air ratio, peak scatter factor, isodose curves are studied. (M.A.C.) [pt

Gamma Knife radiosurgery for vestibular schwannoma: case report and review of the literature.

Science.gov (United States)

Arthurs, Benjamin J; Lamoreaux, Wayne T; Giddings, Neil A; Fairbanks, Robert K; Mackay, Alexander R; Demakas, John J; Cooke, Barton S; Lee, Christopher M

2009-12-18

Vestibular schwannomas, also called acoustic neuromas, are benign tumors of the vestibulocochlear nerve. Patients with these tumours almost always present with signs of hearing loss, and many also experience tinnitus, vertigo, and equilibrium problems. Following diagnosis with contrast enhanced MRI, patients may choose to observe the tumour with subsequent scans or seek active treatment in the form of microsurgery, radiosurgery, or radiotherapy. Unfortunately, definitive guidelines for treating vestibular schwannomas are lacking, because of insufficient evidence comparing the outcomes of therapeutic modalities.We present a contemporary case report, describing the finding of a vestibular schwannoma in a patient who presented with dizziness and a "clicking" sensation in the ear, but no hearing deficit. Audible clicking is a symptom that, to our knowledge, has not been associated with vestibular schwannoma in the literature. We discuss the diagnosis and patient's decision-making process, which led to treatment with Gamma Knife radiosurgery. Treatment resulted in an excellent radiographic response and complete hearing preservation. This case highlights an atypical presentation of vestibular schwannoma, associated with audible "clicks" and normal hearing. We also provide a concise review of the available literature on modern vestibular schwannoma treatment, which may be useful in guiding treatment decisions.

Optimal technique of linear accelerator-based stereotactic radiosurgery for tumors adjacent to brainstem.

Science.gov (United States)

Chang, Chiou-Shiung; Hwang, Jing-Min; Tai, Po-An; Chang, You-Kang; Wang, Yu-Nong; Shih, Rompin; Chuang, Keh-Shih

2016-01-01

Stereotactic radiosurgery (SRS) is a well-established technique that is replacing whole-brain irradiation in the treatment of intracranial lesions, which leads to better preservation of brain functions, and therefore a better quality of life for the patient. There are several available forms of linear accelerator (LINAC)-based SRS, and the goal of the present study is to identify which of these techniques is best (as evaluated by dosimetric outcomes statistically) when the target is located adjacent to brainstem. We collected the records of 17 patients with lesions close to the brainstem who had previously been treated with single-fraction radiosurgery. In all, 5 different lesion catalogs were collected, and the patients were divided into 2 distance groups-1 consisting of 7 patients with a target-to-brainstem distance of less than 0.5cm, and the other of 10 patients with a target-to-brainstem distance of ≥ 0.5 and linear accelerator is only 1 modality can to establish for SRS treatment. Based on statistical evidence retrospectively, we recommend VMAT as the optimal technique for delivering treatment to tumors adjacent to brainstem. Copyright © 2016 American Association of Medical Dosimetrists. All rights reserved.

Stereotactic helium-ion radiosurgery for the treatment of intracranial arteriovenous malformations

International Nuclear Information System (INIS)

Fabrikant, J.I.; Levy, R.P.; Frankel, K.A.; Phillips, M.H.; Lyman, J.T.; Chuang, F.Y.S.; Steinberg, G.K.; Marks, M.P.

1989-12-01

One of the more challenging problems of vascular neurosurgery is the management of surgically-inaccessible arteriovenous malformations (AVMs) of the brain. At Lawrence Berkeley Laboratory, we have developed the method of stereotactic heavy-charged-particle (helium-ion) Bragg peak radiosurgery for treatment of inoperable intracranial AVMs in over 300 patients since 1980 [Fabrikant et al. 1989, Fabrikant et al. 1985, Levy et al. 1989]. This report describes patient selection, treatment method, clinical and neuroradiologic results and complications encountered. 4 refs

LINAC-radiosurgery for nonsecreting pituitary adenomas. Long-term results

Energy Technology Data Exchange (ETDEWEB)

Runge, M.J.R.; Maarouf, M.; Hunsche, S.; Ruge, M.I.; El Majdoub, F.; Treuer, H.; Sturm, V. [Koeln Univ. (Germany). Dept. of Stereotaxy and Functional Neurosurgery; Kocher, M.; Mueller, R.P. [Koeln Univ. (Germany). Dept. of Radiation Oncology; Voges, J. [Magdeburg Univ. (Germany). Dept. of Stereotactic Neurosurgery

2012-04-15

Stereotactic linear accelerator-based radiosurgery (LINAC-RS) is increasingly used for microsurgically inaccessible or recurrent pituitary adenomas. This single-center study evaluates the long-term follow-up after LINAC-RS of nonsecreting pituitary adenomas (NSA). Patients and methods: Between 1992 and August 2008, 65 patients with NSA were treated. Patient treatment and follow-up were conducted according to a prospective protocol. Indications for LINAC-RS were (1) tumor recurrence or (2) residual tumor. Three patients were treated primarily. For analysis of prognostic factors, patients were grouped according to epidemiological or treatment-associated characteristics. Results: A total of 61 patients with a follow-up {>=} 12 months (median 83 months, range 15-186 months, longest follow-up of published radiosurgery series) were evaluated with regard to their clinical, radiological, and endocrinological course. The median tumor volume was 3.5 ml ({+-} 4.3 ml, range 0.3-17.3 ml) treated with a median surface and maximum dose of 13.0 Gy and 29.7 Gy, respectively. Local tumor control was achieved in 98%. One patient died of unrelated cause after 36 months and 1 patient developed a radiation-induced seizure disorder. Visual complications did not occur. In 37 of 41 patients (90.2%), pituitary function remained stable. Maximum dose to the pituitary {<=} 16 Gy and female gender were positive prognostic factors for the preservation of pituitary function. Conclusion: LINAC-RS is a minimally invasive, safe, and effective treatment for recurrent NSA or microsurgically inaccessible residual tumor. LINAC-RS yielded a high rate of local long-term tumor control with a small number of radiation-induced side effects. (orig.)

LINAC-radiosurgery for nonsecreting pituitary adenomas. Long-term results

International Nuclear Information System (INIS)

Runge, M.J.R.; Maarouf, M.; Hunsche, S.; Ruge, M.I.; El Majdoub, F.; Treuer, H.; Sturm, V.; Kocher, M.; Mueller, R.P.; Voges, J.

2012-01-01

Stereotactic linear accelerator-based radiosurgery (LINAC-RS) is increasingly used for microsurgically inaccessible or recurrent pituitary adenomas. This single-center study evaluates the long-term follow-up after LINAC-RS of nonsecreting pituitary adenomas (NSA). Patients and methods: Between 1992 and August 2008, 65 patients with NSA were treated. Patient treatment and follow-up were conducted according to a prospective protocol. Indications for LINAC-RS were (1) tumor recurrence or (2) residual tumor. Three patients were treated primarily. For analysis of prognostic factors, patients were grouped according to epidemiological or treatment-associated characteristics. Results: A total of 61 patients with a follow-up ≥ 12 months (median 83 months, range 15-186 months, longest follow-up of published radiosurgery series) were evaluated with regard to their clinical, radiological, and endocrinological course. The median tumor volume was 3.5 ml (± 4.3 ml, range 0.3-17.3 ml) treated with a median surface and maximum dose of 13.0 Gy and 29.7 Gy, respectively. Local tumor control was achieved in 98%. One patient died of unrelated cause after 36 months and 1 patient developed a radiation-induced seizure disorder. Visual complications did not occur. In 37 of 41 patients (90.2%), pituitary function remained stable. Maximum dose to the pituitary ≤ 16 Gy and female gender were positive prognostic factors for the preservation of pituitary function. Conclusion: LINAC-RS is a minimally invasive, safe, and effective treatment for recurrent NSA or microsurgically inaccessible residual tumor. LINAC-RS yielded a high rate of local long-term tumor control with a small number of radiation-induced side effects. (orig.)

Retrospective analysis of linac-based radiosurgery for arteriovenous malformations and testing of the Flickinger formula in predicting radiation injury

Energy Technology Data Exchange (ETDEWEB)

Cetin, I.A. [Universitair Ziekenhuis Brussel (Belgium). Dept. of Radiation Oncology; Marmara Univ., Ustkaynarca/Pendik (Turkey). Dept. of Radiation Oncology; Ates, R.; Dhaens, J.; Storme, G. [Universitair Ziekenhuis Brussel (Belgium). Dept. of Radiation Oncology

2012-12-15

Background and purpose: The aim of the study was to validate the use of linac-based radiosurgery in arteriovenous malformation (AVM) patients and to predict complications using an integrated logistic formula (ILF) in comparison with clinical outcomes. Patients and methods: The results of radiosurgery in 92 AVM patients were examined. All patients were treated with linac-based radiosurgery. Of these, 70 patients were followed for 12-45 months (median, 24 months) and were analyzed. The treated volume varied from 0.09 to 26.95 cm{sup 3} (median, 2.3 cm{sup 3}) and the median marginal dose was 20 Gy (range, 10.4-22). The median 12-Gy volume was 9.94 cm{sup 3} (range, 0.74-60.09 cm{sup 3}). Patients and lesion characteristics potentially affecting nidus obliteration and excellent outcome were evaluated by performing a log-rank test and univariate and multivariate analyses. The risk for radiation injury (RRI) was calculated with an integrated logistic formula. The predictive power of the RRI was assessed by calculating the area under the receiver operating characteristic (ROC) curve. Results: Follow-up magnetic resonance (MR) angiography revealed complete AVM obliteration in 56 of 70 patients. The MR angiography confirmed an obliteration rate of 80%. The annual hemorrhage rate was 1.4% for the first 2 years after radiosurgery and 0% thereafter. The number of patients with an excellent outcome was 48 (68%). Factors associated with better obliteration were higher radiation dose to the lesion margins [12-Gy volume (V12) > 10 cm{sup 3}], small volume, and a Pollock-Flickinger score less than 1.49; those predicting excellent outcomes were V12 < 10 cm{sup 3}, small volume, and Pollock-Flickinger score less than 1.49, as determined by multivariate analyses. Factors associated with radiation injury were V12 > 10 cm{sup 3} (p=0.03) and volume greater than 2 cm{sup 3} (p=0.001), as determined by a univariate analysis. The analyses showed an ROC of 0.66. Conclusion: These data

Fractionated stereotactically guided radiotherapy and radiosurgery in the treatment of functional and nonfunctional adenomas of the pituitary gland

International Nuclear Information System (INIS)

Milker-Zabel, Stefanie; Debus, Juergen; Thilmann, Christoph; Schlegel, Wolfgang; Wannenmacher, Michael

2001-01-01

Purpose: We evaluated survival rates and side effects after fractionated stereotactically guided radiotherapy (SCRT) and radiosurgery in patients with pituitary adenoma. Methods and Materials: Between 1989 and 1998, 68 patients were treated with FSRT (n=63) or radiosurgery (n=5) for pituitary adenomas. Twenty-six had functional and 42 had nonfunctional adenomas. Follow-up included CT/MRI, endocrinologic, and ophthalmologic examinations. Mean follow-up was 38.7 months. Seven patients received radiotherapy as primary treatment and 39 patients received it postoperatively for residual disease. Twenty-two patients were treated for recurrent disease after surgery. Mean total dose was 52.2 Gy for SCRT, and 15 Gy for radiosurgery. Results: Overall local tumor control was 93% (60/65 patients). Forty-three patients had stable disease based on CT/MRI, while 15 had a reduction of tumor volume. After FSRT, 26% with a functional adenoma had a complete remission and 19% had a reduction of hormonal overproduction after 34 months' mean. Two patients with STH-secreting adenomas had an endocrinologic recurrence, one with an ACTH-secreting adenoma radiologic recurrence, within 54 months. Reduction of visual acuity was seen in 4 patients and partial hypopituitarism in 3 patients. None of the patients developed brain radionecrosis or radiation-induced gliomas. Conclusion: Stereotactically guided radiotherapy is effective and safe in the treatment of pituitary adenomas to improve local control and reduce hormonal overproduction

Stereotactic radiosurgery versus whole-brain radiotherapy after intracranial metastasis resection : A systematic review and meta-analysis

NARCIS (Netherlands)

Lamba, Nayan; Muskens, Ivo S; DiRisio, Aislyn C; Meijer, Louise; Briceno, Vanessa; Edrees, Heba; Aslam, Bilal; Minhas, Sadia; Verhoeff, Joost J.C.; Kleynen, Catharina E.; Smith, Timothy R; Mekary, Rania A; Broekman, Marike L.

2017-01-01

Background: In patients with one to three brain metastases who undergo resection, options for post-operative treatments include whole-brain radiotherapy (WBRT) or stereotactic radiosurgery (SRS) of the resection cavity. In this meta-analysis, we sought to compare the efficacy of each post-operative

Setup Accuracy of the Novalis ExacTrac 6DOF System for Frameless Radiosurgery

International Nuclear Information System (INIS)

Gevaert, Thierry; Verellen, Dirk; Tournel, Koen; Linthout, Nadine; Bral, Samuel; Engels, Benedikt; Collen, Christine; Depuydt, Tom; Duchateau, Michael; Reynders, Truus; Storme, Guy; De Ridder, Mark

2012-01-01

Purpose: Stereotactic radiosurgery using frame-based positioning is a well-established technique for the treatment of benign and malignant lesions. By contrast, a new trend toward frameless systems using image-guided positioning techniques is gaining mainstream acceptance. This study was designed to measure the detection and positioning accuracy of the ExacTrac/Novalis Body (ET/NB) for rotations and to compare the accuracy of the frameless with the frame-based radiosurgery technique. Methods and Materials: A program was developed in house to rotate reference computed tomography images. The angles measured by the system were compared with the known rotations. The accuracy of ET/NB was evaluated with a head phantom with seven lead beads inserted, mounted on a treatment couch equipped with a robotic tilt module, and was measured with a digital water level and portal films. Multiple hidden target tests (HTT) were performed to measure the overall accuracy of the different positioning techniques for radiosurgery (i.e., frameless and frame-based with relocatable mask or invasive ring, respectively). Results: The ET/NB system can detect rotational setup errors with an average accuracy of 0.09° (standard deviation [SD] 0.06°), 0.02° (SD 0.07°), and 0.06° (SD 0.14°) for longitudinal, lateral, and vertical rotations, respectively. The average positioning accuracy was 0.06° (SD 0.04°), 0.08° (SD 0.06°), and 0.08° (SD 0.07°) for longitudinal, lateral and vertical rotations, respectively. The results of the HTT showed an overall three-dimensional accuracy of 0.76 mm (SD 0.46 mm) for the frameless technique, 0.87 mm (SD 0.44 mm) for the relocatable mask, and 1.19 mm (SD 0.45 mm) for the frame-based technique. Conclusions: The study showed high detection accuracy and a subdegree positioning accuracy. On the basis of phantom studies, the frameless technique showed comparable accuracy to the frame-based approach.

MO-A-BRD-08: Radiosurgery Beyond Cancer: Real-Time Target Localization and Treatment Planning for Cardiac Radiosurgery Under MRI Guidance

Energy Technology Data Exchange (ETDEWEB)

Ipsen, S [University of Luebeck, Luebeck, SH (Germany); University of Sydney, Camperdown (Australia); Blanck, O [CyberKnife Zentrum Norddeutschland, Guestrow, MV (Germany); Oborn, B [Illawarra Cancer Care Centre, Wollongong, NSW (Australia); Bode, F [Medical Clinic II, Section for Electrophysiology, UKSH, Luebeck, SH (Germany); Liney, G [Ingham Institute for Applied Medical Research, Liverpool, NSW (United Kingdom); Keall, P [University of Sydney, Camperdown (Australia)

2014-06-15

Purpose: Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting >2.5M Americans and >4.5M Europeans. AF is usually treated with minimally-invasive, time consuming catheter ablation techniques. Radiosurgery of the pulmonary veins (PV) has been proposed for AF treatment, however is challenging due to the complex respiratory and cardiac motion patterns. We hypothesize that an MRI-linac could solve the difficult real-time targeting and adaptation problem. In this study we quantified target motion ranges on cardiac MRI and analyzed the dosimetric benefits of margin reduction assuming real-time MRI tracking was applied. Methods: For the motion study, four human subjects underwent real-time cardiac MRI under free breathing. The target motion on coronal and axial cine planes was analyzed using a template matching algorithm. For the planning study, an ablation line at each PV antrum was defined as target on an AF patient scheduled for catheter ablation. Various safety margins ranging from 0mm (perfect tracking) to 8mm (untracked motion) were added to the target defining the PTV. 30Gy single fraction IMRT plans were then generated. Finally, the influence of a 1T magnetic field on treatment beam delivery was calculated using the Geant4 Monte Carlo algorithm to simulate the dosimetric impact of MRI guidance. Results: The motion study showed the mean respiratory motion of the target area on MRI was 8.4mm (SI), 1.7mm (AP) and 0.3mm (LR). Cardiac motion was small (<2mm). The planning study showed that with increasing safety margins to encompass untracked motion, dose tolerances for OARs such as the esophagus and airways were exceeded by >100%. The magnetic field had little impact on the dose distribution. Conclusion: Our results indicate that real-time MRI tracking of the PVs seems feasible. Accurate image guidance for high-dose AF radiosurgery is essential since safety margins covering untracked target motion will result in unacceptable treatment plans.

Prediction of complications in Gamma Knife radiosurgery of arteriovenous malformations

International Nuclear Information System (INIS)

Lax, I.; Karlsson, B.

1996-01-01

The incidence of complications following radiosurgical treatment of arteriovenous malformations (AVM) is presented. A simple relationship exists between average dose and risk of complications, and on this basis a model is presented that gives a qualitatively correct description of this relationship. The parameters of the model have been determined using a clinical material of 862 AVM treatments to give a quantitativley correct description of the risk of complications. The dose-response curve is described by a double-exponential function. An accurate description of the dose-response curve at high dose levels is shown to be very important in radiosurgery. (orig.)

Radiosurgery in the Management of Intractable Mesial Temporal Lobe Epilepsy.

Science.gov (United States)

Peñagarícano, José; Serletis, Demitre

2015-09-01

Mesial temporal lobe epilepsy (MTLE) describes recurrent seizure activity originating from the depths of the temporal lobe. MTLE patients who fail two trials of medication now require testing for surgical candidacy at an epilepsy center. For these individuals, temporal lobectomy offers the greatest likelihood for seizure-freedom (up to 80-90%); unfortunately, this procedure remains largely underutilized. Moreover, for select patients unable to tolerate open surgery, novel techniques are emerging for selective ablation of the mesial temporal structures, including stereotactic radiosurgery (SRS). We present here a review of SRS as a potential therapy for MTLE, when open surgery is not an option.

Impact of collimator leaf width on stereotactic radiosurgery and 3D conformal radiotherapy treatment plans

International Nuclear Information System (INIS)

Kubo, H. Dale; Wilder, Richard B.; Pappas, Conrad T.E.

1999-01-01

Purpose: The authors undertook a study to analyze the impact of collimator leaf width on stereotactic radiosurgery and 3D conformal radiotherapy treatment plans. Methods and Materials: Twelve cases involving primary brain tumors, metastases, or arteriovenous malformations that had been planned with BrainLAB's conventional circular collimator-based radiosurgery system were re-planned using a β-version of BrainLAB's treatment planning software that is compatible with MRC Systems' and BrainLAB's micro-multileaf collimators. These collimators have a minimum leaf width of 1.7 mm and 3.0 mm, respectively, at isocenter. The clinical target volumes ranged from 2.7-26.1 cc and the number of static fields ranged from 3-5. In addition, for 4 prostate cancer cases, 2 separate clinical target volumes were planned using MRC Systems' and BrainLAB's micro-multileaf collimators and Varian's multileaf collimator: the smaller clinical target volume consisted of the prostate gland and the larger clinical target volume consisted of the prostate and seminal vesicles. For the prostate cancer cases, treatment plans were generated using either 6 or 7 static fields. A 'PITV ratio', which the Radiation Therapy Oncology Group defines as the volume encompassed by the prescription isodose surface divided by the clinical target volume, was used as a measure of the quality of treatment plans (a PITV ratio of 1.0-2.0 is desirable). Bladder and rectal volumes encompassed by the prescription isodose surface, isodose distributions and dose volume histograms were also analyzed for the prostate cancer patients. Results: In 75% of the cases treated with radiosurgery, a PITV ratio between 1.0-2.0 could be achieved using a micro-multileaf collimator with a leaf width of 1.7-3.0 mm at isocenter and 3-5 static fields. When the clinical target volume consisted of the prostate gland, the micro-multileaf collimator with a minimum leaf width of 3.0 mm allowed one to decrease the median volume of bladder and

Secondary necrosis: the radiosurgery in the cerebral arteriovenous malformations. CT and MR aspects

International Nuclear Information System (INIS)

Pina, J.I.; Medrano, J.; Benito, J.L. de; Sierra, R. la; Feijoo, R.; Villavieja, J.L.

1995-01-01

The Ct and MR findings are presented for two patients previously diagnosed as having cerebral arteriovenous malformations (AVM), treated by means of stereotaxic radiosurgery. The study of their course following corticosteroid therapy is also reported. The diagnosis was based on changes in the MR signal and density on CT and on their late onset, and was confirmed by puncture. The good clinical and radiological course is discussed. (Author) 10 refs

Stereotactic Radiosurgery (SRS) / Stereotactic body radiotherapy (SBRT): Benefit to Irish patients and Irish Healthcare Economy

LENUS (Irish Health Repository)

Cagney, DN

2017-01-01

Cancer incidence across Europe is projected to rise rapidly over the next decade. This rising cancer incidence is mirrored by increasing use of and indications for stereotactic radiation. This paper seeks to summarize the exponential increase in indications for stereotactic radiotherapy as well as the evolving economic advantages of stereotactic radiosurgery and stereotactic body radiotherapy

Frameless stereotactic radiosurgery of a solitary liver metastasis using active breathing control and stereotactic ultrasound

International Nuclear Information System (INIS)

Boda-Heggemann, J.; Walter, C.; Mai, S.; Dobler, B.; Wenz, F.; Lohr, F.; Dinter, D.

2006-01-01

Background and purpose: radiosurgery of liver metastases is effective but a technical challenge due to respiration-induced movement. The authors report on the initial experience of the combination of active breathing control (ABC registered ) with stereotactic ultrasound (B-mode acquisition and targeting [BAT registered ]) for frameless radiosurgery. Patient and methods: a patient with a solitary, inoperable liver metastasis from cholangiocellular carcinoma is presented. ABC registered was used for tumor/liver immobilization. Tumor/liver position was controlled and corrected using ultrasound (BAT registered ). The tumor was irradiated with a single dose of 24 Gy. Results: using ABC registered , the motion of the tumor was significantly reduced and the overall positioning error was registered allowed a rapid localization of the lesion during breath hold which could be performed without difficulties for 20 s. Overall treatment time was acceptable (30 min). Conclusion: frameless stereotactic radiotherapy with the combination of ABC registered and BAT registered allows the delivery of high single doses to targets accessible to ultrasound with high precision comparable to a frame-based approach. (orig.)

Adaptation and validation of a commercial head phantom for cranial radiosurgery dosimetry end-to-end audit.

Science.gov (United States)

Dimitriadis, Alexis; Palmer, Antony L; Thomas, Russell A S; Nisbet, Andrew; Clark, Catharine H

2017-06-01

To adapt and validate an anthropomorphic head phantom for use in a cranial radiosurgery audit. Two bespoke inserts were produced for the phantom: one for providing the target and organ at risk for delineation and the other for performing dose measurements. The inserts were tested to assess their positional accuracy. A basic treatment plan dose verification with an ionization chamber was performed to establish a baseline accuracy for the phantom and beam model. The phantom and inserts were then used to perform dose verification measurements of a radiosurgery plan. The dose was measured with alanine pellets, EBT extended dose film and a plastic scintillation detector (PSD). Both inserts showed reproducible positioning (±0.5 mm) and good positional agreement between them (±0.6 mm). The basic treatment plan measurements showed agreement to the treatment planning system (TPS) within 0.5%. Repeated film measurements showed consistent gamma passing rates with good agreement to the TPS. For 2%-2 mm global gamma, the mean passing rate was 96.7% and the variation in passing rates did not exceed 2.1%. The alanine pellets and PSD showed good agreement with the TPS (-0.1% and 0.3% dose difference in the target) and good agreement with each other (within 1%). The adaptations to the phantom showed acceptable accuracies. The presence of alanine and PSD do not affect film measurements significantly, enabling simultaneous measurements by all three detectors. Advances in knowledge: A novel method for thorough end-to-end test of radiosurgery, with capability to incorporate all steps of the clinical pathway in a time-efficient and reproducible manner, suitable for a national audit.

Long-Term Follow-up of Acoustic Schwannoma Radiosurgery With Marginal Tumor Doses of 12 to 13 Gy

International Nuclear Information System (INIS)

Chopra, Rahul; Kondziolka, Douglas; Niranjan, Ajay; Lunsford, L. Dade; Flickinger, John C.

2007-01-01

Purpose: To define long-term tumor control and clinical outcomes of radiosurgery with marginal tumor doses of 12 to 13 Gy for unilateral acoustic schwannoma. Methods and Materials: A total of 216 patients with previously untreated unilateral acoustic schwannoma underwent Gamma Knife radiosurgery between 1992 and 2000 with marginal tumor doses of 12 to 13 Gy (median, 13 Gy). Median follow-up was 5.7 years (maximum, 12 years; 41 patients with >8 years). Treatment volumes were 0.08-37.5 cm 3 (median, 1.3 cm 3 ). Results: The 10-year actuarial resection-free control rate was 98.3% ± 1.0%. Three patients required tumor resection: 2 for tumor growth and 1 partial resection for an enlarging adjacent subarachnoid cyst. Among 121 hearing patients with >3 years of follow-up, crude hearing preservation rates were 71% for keeping the same Gardner-Robertson hearing level, 74% for serviceable hearing, and 95% for any testable hearing. For 25 of these patients with intracanalicular tumors, the respective rates for preserving the same Gardner-Robertson level, serviceable hearing, and testable hearing were 80%, 88%, and 96%. Ten-year actuarial rates for preserving the same Gardner-Robertson hearing levels, serviceable hearing, any testable hearing, and unchanged facial and trigeminal nerve function were 44.0% ± 11.7%, 44.5% ± 10.5%, 85.3% ± 6.2%, 100%, and 94.9% ± 1.8%, respectively. Conclusions: Acoustic schwannoma radiosurgery with 12 to 13 Gy provides high rates of long-term tumor control and cranial nerve preservation after long-term follow-up

Improvement of radiological penumbra using intermediate energy photons (IEP) for stereotactic radiosurgery

International Nuclear Information System (INIS)

O'Malley, Lauren; Pignol, Jean-Philippe; Beachey, David J; Keller, Brian M; Presutti, Joseph; Sharpe, Michael

2006-01-01

Using efficient immobilization and dedicated beam collimation devices, stereotactic radiosurgery ensures highly conformal treatment of small tumours with limited microscopic extension. One contribution to normal tissue irradiation remains the radiological penumbra. This work aims at demonstrating that intermediate energy photons (IEP), above orthovoltage but below megavoltage, improve dose distribution for stereotactic radiosurgery for small irradiation field sizes due to a dramatic reduction of radiological penumbra. Two different simulation systems were used: (i) Monte Carlo simulation to investigate the dose distribution of monoenergetic IEP between 100 keV and 1 MeV in water phantom; (ii) the Pinnacle 3 TPS including a virtual IEP unit to investigate the dosimetry benefit of treating with 11 non-coplanar beams a 2 cm tumour in the middle of a brain adjacent to a 1 mm critical structure. Radiological penumbrae below 300 μm are generated for field size below 2 x 2 cm 2 using monoenergetic IEP beams between 200 and 400 keV. An 800 kV beam generated in a 0.5 mm tungsten target maximizes the photon intensity in this range. Pinnacle 3 confirms the dramatic reduction in penumbra size. DVHs show for a constant dose distribution conformality, improved dose distribution homogeneity and better sparing of critical structures using a 800 kV beam compared to a 6 MV beam

Improvement of radiological penumbra using intermediate energy photons (IEP) for stereotactic radiosurgery

Science.gov (United States)

O'Malley, Lauren; Pignol, Jean-Philippe; Beachey, David J.; Keller, Brian M.; Presutti, Joseph; Sharpe, Michael

2006-05-01

Using efficient immobilization and dedicated beam collimation devices, stereotactic radiosurgery ensures highly conformal treatment of small tumours with limited microscopic extension. One contribution to normal tissue irradiation remains the radiological penumbra. This work aims at demonstrating that intermediate energy photons (IEP), above orthovoltage but below megavoltage, improve dose distribution for stereotactic radiosurgery for small irradiation field sizes due to a dramatic reduction of radiological penumbra. Two different simulation systems were used: (i) Monte Carlo simulation to investigate the dose distribution of monoenergetic IEP between 100 keV and 1 MeV in water phantom; (ii) the Pinnacle3 TPS including a virtual IEP unit to investigate the dosimetry benefit of treating with 11 non-coplanar beams a 2 cm tumour in the middle of a brain adjacent to a 1 mm critical structure. Radiological penumbrae below 300 µm are generated for field size below 2 × 2 cm2 using monoenergetic IEP beams between 200 and 400 keV. An 800 kV beam generated in a 0.5 mm tungsten target maximizes the photon intensity in this range. Pinnacle3 confirms the dramatic reduction in penumbra size. DVHs show for a constant dose distribution conformality, improved dose distribution homogeneity and better sparing of critical structures using a 800 kV beam compared to a 6 MV beam.

CyberKnife Radiosurgery in the Multimodal Management of Patients with Cushing Disease.

Science.gov (United States)

Moore, Justin M; Sala, Elisa; Amorin, Alvaro; Martinez, Hector; Bhowmik, Aprotim C; Chang, Steven D; Soltys, Scott G; Harsh, Griffith R; Katznelson, Laurence

2018-04-01

Surgery is the primary treatment for Cushing disease. When surgery is unsuccessful in normalizing hypercortisolism, adjuvant radiation, such as stereotactic radiosurgery, may be useful to improve biochemical control. This retrospective study included a cohort of consecutive patients treated with CyberKnife (CK) radiosurgery for active Cushing disease at Stanford Hospital and Clinics. As first-line treatment, all patients underwent transsphenoidal surgery with histologic demonstration of an adrenocorticotropic hormone-producing pituitary adenoma. CK was performed as adjuvant therapy for persistent or recurrent disease. The median time between surgery and CK was 14 ± 34 months. Before CK, median maximal diameter of tumors was 9 mm (range, 7-32 mm), with cavernous sinus invasion in all patients (100%) and abutment of the optic chiasm in 1 patient (14.2%). With an average follow-up of 55.4 months, normalization of hypercortisolism was achieved in 4 patients (57.1%): 2 patients (28.5%) achieved normalization of the hypothalamic-pituitary-adrenal axis without glucocorticoid replacement, and 2 patients developed hypoadrenalism (28.5%). The median time to biochemical remission was 12.5 months. Hypopituitarism occurred in only 1 patient (14.2%), and no patients had visual complications. Time between surgery and radiotherapy of Cushing disease, we demonstrate that CK is an effective treatment with rare complications. Copyright © 2018 Elsevier Inc. All rights reserved.

Effects of heavy-ion radiosurgery on the hemopoietic function of the silkworm Bombyx mori

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Tu, Zhen-Li; Kobayashi, Yasuhiko; Watanabe, Hiroshi; Yamamoto, Kazuo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Kiguchi, Kenji [SHINSHU Univ., Ueda, Nagano (Japan). Faculty of Textile Science and Technology

2002-09-01

To study the effects of heavy-ion radiosurgery on the hemopoietic function of a silkworm, hemopoietic organs of larvae were locally irradiated with carbon-ion beams, and the changes in the hemocyte density and in the hemocyte function were investigated. When the larvae were irradiated by 50 Gy to 300 Gy carbon ions on the 3rd day of the 4th instar, the hemocyte densities did not change for a while, though they gradually increased at a later stage, but were finally still significantly lower than those of unirradiated controls. The hemocyte densities of the larvae irradiated at different developmental stages showed suppressed increments, and carbon-ion irradiation given to larvae at early stages compared to the later stages had a significant suppressive effect on the hemocyte densities. On unilateral irradiated larvae a hemocyte intermediate increment between those of bilateral irradiated larvae and unirradiated controls was observed. The percentage of dead hemocytes was obviously higher for irradiated larvae than unirradiated controls during the later 5th instar. Thus, it is evident that carbon-ion radiosurgery on hemopoietic organs of silkworm induced not only a quantitative change, but also a qualitative change in the hemocytes. (author)

Gamma knife radiosurgery in the treatment of a meningioma in a patient on maintenance hemodialysis: A case report

International Nuclear Information System (INIS)

Matsuo, H.; Nakamura, K.; Hayashi, J.; Nakura, T.; Saruki, K.; Andoh, Y.; Shibazaki, T.; Kubo, K.

1994-01-01

To our knowledge, this is the first report ever on the implementation and results of gamma knife radiosurgery in a regularly dialysed patient. The case presented is that of a 59 year-old female patient with a meningioma. Her initial clinical presentation was with sustained headache. Diagnosis was made by using a brain CT scan and MR imaging. Treatment was performed literally without opening the skull. There was only one complication, namely that of postirradiation brain edema, which developed 19 weeks after the operation, and responded dramatically to steroid administration. This is one of the rare side effects of gamma knife therapy, but does not seem to be related to the fact that the patient was uremic. Gamma knife therapy was successful in this patient and her safety was no more compromised than that of a nonuremic patient undergoing radiosurgery. (authors)

Gamma Knife radiosurgery for vestibular schwannoma: case report and review of the literature

Directory of Open Access Journals (Sweden)

Fairbanks Robert K

2009-12-01

Full Text Available Abstract Vestibular schwannomas, also called acoustic neuromas, are benign tumors of the vestibulocochlear nerve. Patients with these tumours almost always present with signs of hearing loss, and many also experience tinnitus, vertigo, and equilibrium problems. Following diagnosis with contrast enhanced MRI, patients may choose to observe the tumour with subsequent scans or seek active treatment in the form of microsurgery, radiosurgery, or radiotherapy. Unfortunately, definitive guidelines for treating vestibular schwannomas are lacking, because of insufficient evidence comparing the outcomes of therapeutic modalities. We present a contemporary case report, describing the finding of a vestibular schwannoma in a patient who presented with dizziness and a "clicking" sensation in the ear, but no hearing deficit. Audible clicking is a symptom that, to our knowledge, has not been associated with vestibular schwannoma in the literature. We discuss the diagnosis and patient's decision-making process, which led to treatment with Gamma Knife radiosurgery. Treatment resulted in an excellent radiographic response and complete hearing preservation. This case highlights an atypical presentation of vestibular schwannoma, associated with audible "clicks" and normal hearing. We also provide a concise review of the available literature on modern vestibular schwannoma treatment, which may be useful in guiding treatment decisions.

Gamma Knife radiosurgery for large vestibular schwannomas greater than 3 cm in diameter.

Science.gov (United States)

Huang, Cheng-Wei; Tu, Hsien-Tang; Chuang, Chun-Yi; Chang, Cheng-Siu; Chou, Hsi-Hsien; Lee, Ming-Tsung; Huang, Chuan-Fu

2018-05-01

OBJECTIVE Stereotactic radiosurgery (SRS) is an important alternative management option for patients with small- and medium-sized vestibular schwannomas (VSs). Its use in the treatment of large tumors, however, is still being debated. The authors reviewed their recent experience to assess the potential role of SRS in larger-sized VSs. METHODS Between 2000 and 2014, 35 patients with large VSs, defined as having both a single dimension > 3 cm and a volume > 10 cm 3 , underwent Gamma Knife radiosurgery (GKRS). Nine patients (25.7%) had previously undergone resection. The median total volume covered in this group of patients was 14.8 cm 3 (range 10.3-24.5 cm 3 ). The median tumor margin dose was 11 Gy (range 10-12 Gy). RESULTS The median follow-up duration was 48 months (range 6-156 months). All 35 patients had regular MRI follow-up examinations. Twenty tumors (57.1%) had a volume reduction of greater than 50%, 5 (14.3%) had a volume reduction of 15%-50%, 5 (14.3%) were stable in size (volume change 3 cm and a volume > 10 cm 3 and tolerable mass effect can be managed satisfactorily with GKRS. Tumor volume ≥ 15 cm 3 is a significant factor predicting poor tumor control following GKRS.

Volumetric Radiosurgery for 1 to 10 Brain Metastases: A Multicenter, Single-Arm, Phase 2 Study

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Nichol, Alan, E-mail: anichol@bccancer.bc.ca [Department of Radiation Oncology, BC Cancer Agency, Vancouver Centre, Vancouver, British Columbia (Canada); University of British Columbia, Vancouver, British Columbia (Canada); Ma, Roy [Department of Radiation Oncology, BC Cancer Agency, Vancouver Centre, Vancouver, British Columbia (Canada); University of British Columbia, Vancouver, British Columbia (Canada); Hsu, Fred [University of British Columbia, Vancouver, British Columbia (Canada); Department of Radiation Oncology, BC Cancer Agency, Abbotsford Centre, Abbotsford, British Columbia (Canada); Gondara, Lovedeep [Department of Surveillance and Outcomes, BC Cancer Agency, Vancouver, British Columbia (Canada); Carolan, Hannah [Department of Radiation Oncology, BC Cancer Agency, Vancouver Centre, Vancouver, British Columbia (Canada); University of British Columbia, Vancouver, British Columbia (Canada); Olson, Robert [University of British Columbia, Vancouver, British Columbia (Canada); Department of Radiation Oncology, BC Cancer Agency, Centre for the North, Prince George, British Columbia (Canada); Schellenberg, Devin [University of British Columbia, Vancouver, British Columbia (Canada); Department of Radiation Oncology, BC Cancer Agency, Fraser Valley Centre, Surrey, British Columbia (Canada); Germain, François [University of British Columbia, Vancouver, British Columbia (Canada); Department of Radiation Oncology, BC Cancer Agency, Sindi Ahluwalia Centre for the Southern Interior, Kelowna, British Columbia (Canada); Cheung, Arthur [University of British Columbia, Vancouver, British Columbia (Canada); Department of Radiation Oncology, BC Cancer Agency, Fraser Valley Centre, Surrey, British Columbia (Canada); Peacock, Michael [Department of Radiation Oncology, BC Cancer Agency, Vancouver Centre, Vancouver, British Columbia (Canada); University of British Columbia, Vancouver, British Columbia (Canada); and others

2016-02-01

Purpose: Interest is growing in treating multiple brain metastases with radiosurgery. We report on the effectiveness and tolerability of volumetric radiosurgery (VRS). Methods and Materials: We enrolled patients with a ≥6-month estimated life expectancy and 1 to 10 brain metastases with a diameter of ≤3 cm at 5 cancer centers. Volumetric radiosurgery was delivered in 5 fractions with 98% target coverage, prescribed as 95% of 50 Gy (47.5 Gy in 5 fractions) to the metastases with no margin and 95% of 40 Gy (38 Gy in 5 fractions) to their 2-mm planning target volumes, concurrent with 20 Gy to the whole brain planning target volume. The treatment was delivered with daily image guidance using conventional linear accelerators and volumetric modulated arc therapy. A magnetic resonance imaging scan was obtained every 3 months. The primary endpoint was the 3-month objective response in the brain according to the Response Evaluation Criteria in Solid Tumors, version 1.1. The principal secondary endpoint was 1-year actuarial control of treated metastases. Toxicities were graded using the Common Terminology Criteria for Adverse Events, version 4.0. The present study is registered with (ClinicalTrials.gov) ( (clinicaltrials.gov) identifier (NCT01046123)). Results: From July 2010 to May 2013, 60 patients underwent VRS with 47.5 Gy in 5 fractions for 12 metastases in the thalamus and basal ganglia (deep metastases) and 207 non-deep metastases. The median follow-up period was 30.5 months, and the median survival was 10.1 months. For the 43 patients assessable at 3 months, the objective response in the brain was 56%. The treated metastases were controlled in 88% of patients at 1 year and 84% at 3 years. Overall survival did not differ for patients with 4 to 10 versus 1 to 3 metastases (hazard ratio 1.18, P=.6). The crude incidence of severe radionecrosis (grade 3-5) was 25% (3 of 12) per deep metastasis, 1.9% (4 of 219) per non-deep metastasis, and 10% (6 of 60

Intractable trigeminal neuralgia: A single institution experience in 26 patients treated with stereotactic gamma knife radiosurgery

International Nuclear Information System (INIS)

Mark, Rufus J.; Duma, Christopher M.; Jacques, Dean B.; Kopyov, Oleg V.; Copcutt, Brian

1996-01-01

Purpose: In patients with trigeminal neuralgia, severe pain can persist, or recur despite aggressive medical management and open surgery. Recently, Gamma Knife radiosurgery has been used with promising results. We report on our series of 26 patients with intractable trigeminal neuralgia treated with stereotactic Gamma Knife radiosurgery. Materials and Methods: Between 1991 and 1995, 26 patients with intractable trigeminal neuralgia were treated at our institution using stereotactic Gamma Knife radiosurgery. Medical management had failed in all cases. In addition, 13 patients underwent a total of 20 open surgeries, with transient, or no pain relief. There were 19 females, and 7 males. Patient ages ranged from 37 to 87 years, with a median of 74 years. All patients were treated with a 201 source Cobalt-60 Gamma Knife unit. All patients underwent placement of the Leksell frame, followed by MRI scanning and computer treatment planning. The target in all patients was the fifth cranial nerve root entry zone into the brainstem. Twenty-five patients received between 64.3 to 70 Gy prescribed to Dmax in one shot. One patient received 120 Gy to Dmax in one shot. The 4 mm collimator was used in 22 cases, and the 8 mm in 4 cases. Follow-up ranged from 5 to 55 months, with a median of 19 months. Complete resolution (CR) of pain was scored when the patient reported being pain free off all medication. Partial resolution (PR) was scored when the patient reported > 50% pain reduction after Gamma Knife treatment. Results: At last follow-up, 84.6% ((22(26))) reported CR or PR of pain after Gamma Knife treatment. Forty-two percent ((11(26))) of patients reported CR, and 42%((11(26))) reported PR of pain. There was a dose response. In patients receiving < 70 Gy, 25% ((3(12))) reported CR, while 57% ((8(14))) of those receiving ≥ 70 Gy reported CR. Complications occurred in two (8%) patients. One patient developed transient numbness of the face after 70 Gy, and a second patient

Indications of Gamma knife radiosurgery for vestibular schwannomas

International Nuclear Information System (INIS)

Fukuoka, Seiji; Takanashi, Masami; Hojyo, Atsufumi; Tanaka, Chiharu; Konishi, Masanori; Nakamura, Hirohiko

2007-01-01

The purpose of this study was to investigate the indication of gamma knife radiosurgery for vestibular schwannomas by analyzing tumor control and possible complications using low marginal doses and conformal multiple shots to fit irregular tumor shapes. The authors evaluated 223 patients with followed-up periods ranging from 5 years to 15 years (mean 7.7 years, median 7.4 years). Marginal doses were 9 to 15 Gy (mean 12.5 Gy, median 12 Gy) with corresponding treatment volumes being between 0.1 and 18.7 cm 3 (mean 2.6 cm 3 , median 1.8 cm 3 ). The number of isocenters varied from 2 to 24 shots (mean 9, median 9.2). The actuarial tumor control rates were 95% at 5 years and 94% at 7 years, respectively. Larger tumors (p=0.0068) and those in younger patients (p=0.093) tended to recur significantly. The preservation rates of useful hearing were 84%, 71%, and 64% at 2, 4, and 7 years, respectively. The most deterioration seemed to occur in cases with elderly patients (p=0.0048). Facial and trigeminal functions were preserved at 100%, and 97.8%, respectively. Amongst all patients, 20.6% developed transient dizziness, with persistent dizziness remaining in 1.5% of the total. Fifty-six other patients not in the long-term evaluation consecutively underwent caloric testing and static stabilometry as well as neurological examinations to evaluate vestibular function in detail, both before and after gamma knife radiosurgery (GKRS). The results showed that 90% of the patients had already developed vestibular dysfunction before the treatment despite reported symptoms of dizziness. GKRS did not significantly affect vestibular function. Hydrocephalus was recognized in 5.5% of all patients, and seemed to occur primarily in cases with larger tumors (p=0.0189). GKRS provides a safe and effective therapy for small to medium sized tumors up to 8 cm 3 . Long-term hearing preservation rate may be affected by presbycusis in elderly patients. (author)

The safety and efficacy of robotic image-guided radiosurgery system treatment for intra- and extracranial lesions: A systematic review of the literature

International Nuclear Information System (INIS)

Calcerrada Diaz-Santos, Nieves; Blasco Amaro, Juan Antonio; Cardiel, Gloria Ariza; Andradas Aragones, Elena

2008-01-01

Background: The CyberKnife is a new, frameless stereotactic radiosurgery system. This work reviews its safety and efficacy in the treatment of intra- and extracranial lesions. Methods: A literature search was made of the Medline, Embase, Pascal Biomed, CINAHL and Cancerlit databases. Health technology assessment reports on stereotactic radiosurgery systems were also consulted. All searches were made in June 2007. Data on efficacy and safety were extracted and then synthesized into the present review. Results: Thirty five clinical studies were identified, the majority of which included no patient comparison group. These studies assessed the use of the CyberKnife mainly in the treatment of primary and metastatic intracranial and spinal tumours. Conclusions: The CyberKnife system allows to carry out standard radiosurgical and fractionated stereotactic radiotherapy procedures. The use of this system offers an alternative for the treatment of inoperable tumours, and of lesions located close to critical structures that cannot be treated using other types of stereotactic radiosurgery system. Unfortunately, the quality of the reviewed papers still does not allow definite conclusions to be drawn regarding the safety and efficacy of these treatments

A Review of Stereotactic Radiosurgery Practice in the Management of Skull Base Meningiomas

OpenAIRE

Vera, Elena; Iorgulescu, J. Bryan; Raper, Daniel M.S.; Madhavan, Karthik; Lally, Brian E.; Morcos, Jacques; Elhammady, Samy; Sherman, Jonathan; Komotar, Ricardo J.

2014-01-01

Gross total resection of skull base meningiomas poses a surgical challenge due to their proximity to neurovascular structures. Once the gold standard therapy for skull base meningiomas, microsurgery has been gradually replaced by or used in combination with stereotactic radiosurgery (SRS). This review surveys the safety and efficacy of SRS in the treatment of cranial base meningiomas including 36 articles from 1991 to 2010. SRS produces excellent tumor control with low morbidity rates compare...

Quality Assurance Results for a Commercial Radiosurgery System: A Communication.

Science.gov (United States)

Ruschin, Mark; Lightstone, Alexander; Beachey, David; Wronski, Matt; Babic, Steven; Yeboah, Collins; Lee, Young; Soliman, Hany; Sahgal, Arjun

2015-10-01

The purpose of this communication is to inform the radiosurgery community of quality assurance (QA) results requiring attention in a commercial FDA-approved linac-based cone stereo-tactic radiosurgery (SRS) system. Standard published QA guidelines as per the American Association of Physics in Medicine (AAPM) were followed during the SRS system's commissioning process including end-to-end testing, cone concentricity testing, image transfer verification, and documentation. Several software and hardware deficiencies that were deemed risky were uncovered during the process and QA processes were put in place to mitigate these risks during clinical practice. In particular, the present work focuses on daily cone concentricity testing and commissioning-related findings associated with the software. Cone concentricity/alignment is measured daily using both optical light field inspection, as well as quantitative radiation field tests with the electronic portal imager. In 10 out of 36 clini-cal treatments, adjustments to the cone position had to be made to align the cone with the collimator axis to less than 0.5 mm and on two occasions the pre-adjustment measured offset was 1.0 mm. Software-related errors discovered during commissioning included incorrect transfer of the isocentre in DICOM coordinates, improper handling of non-axial image sets, and complex handling of beam data, especially for multi-target treatments. QA processes were established to mitigate the occurrence of the software errors. With proper QA processes, the reported SRS system complies with tolerances set out in established guidelines. Discussions with the vendor are ongoing to address some of the hardware issues related to cone alignment. © The Author(s) 2014.

Stereotactic radiosurgery for the treatment of mesial temporal lobe epilepsy.

Science.gov (United States)

Feng, E-S; Sui, C-B; Wang, T-X; Sun, G-L

2016-12-01

Stereotactic radiosurgery (RS) is a potential option for some patients with temporal lobe epilepsy (TLE). The aim of this meta-analysis was to determine the pooled seizure-free rate and the time interval to seizure cessation in patients with lesions in the mesial temporal lobe, and who were eligible for either stereotactic or gamma knife RS. We searched the Medline, Cochrane, EMBASE, and Google Scholar databases using combinations of the following terms: RS, stereotactic radiosurgery, gamma knife, and TLE. We screened 103 articles and selected 13 for inclusion in the meta-analysis. Significant study heterogeneity was detected; however, the included studies displayed an acceptable level of quality. We show that approximately half of the patients were seizure free over a follow-up period that ranged from 6 months to 9 years [pooled estimate: 50.9% (95% confidence interval: 0.381-0.636)], with an average of 14 months to seizure cessation [pooled estimate: 14.08 months (95% confidence interval: 11.95-12.22 months)]. Nine of 13 included studies reported data for adverse events (AEs), which included visual field deficits and headache (the two most common AEs), verbal memory impairment, psychosis, psychogenic non-epileptic seizures, and dysphasia. Patients in the individual studies experienced AEs at rates that ranged from 8%, for non-epileptic seizures, to 85%, for headache. Our findings indicate that RS may have similar or slightly less efficacy in some patients compared with invasive surgery. Randomized controlled trials of both treatment regimens should be undertaken to generate an evidence base for patient decision-making. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Technical Note: Evaluation of the systematic accuracy of a frameless, multiple image modality guided, linear accelerator based stereotactic radiosurgery system

Energy Technology Data Exchange (ETDEWEB)

Wen, N., E-mail: nwen1@hfhs.org; Snyder, K. C.; Qin, Y.; Li, H.; Siddiqui, M. S.; Chetty, I. J. [Department of Radiation Oncology, Henry Ford Health System, 2799 West Brand Boulevard, Detroit, Michigan 48202 (United States); Scheib, S. G.; Schmelzer, P. [Varian Medical System, Täfernstrasse 7, Dättwil AG 5405 (Switzerland)

2016-05-15

Purpose: To evaluate the total systematic accuracy of a frameless, image guided stereotactic radiosurgery system. Methods: The localization accuracy and intermodality difference was determined by delivering radiation to an end-to-end prototype phantom, in which the targets were localized using optical surface monitoring system (OSMS), electromagnetic beacon-based tracking (Calypso®), cone-beam CT, “snap-shot” planar x-ray imaging, and a robotic couch. Six IMRT plans with jaw tracking and a flattening filter free beam were used to study the dosimetric accuracy for intracranial and spinal stereotactic radiosurgery treatment. Results: End-to-end localization accuracy of the system evaluated with the end-to-end phantom was 0.5 ± 0.2 mm with a maximum deviation of 0.9 mm over 90 measurements (including jaw, MLC, and cone measurements for both auto and manual fusion) for single isocenter, single target treatment, 0.6 ± 0.4 mm for multitarget treatment with shared isocenter. Residual setup errors were within 0.1 mm for OSMS, and 0.3 mm for Calypso. Dosimetric evaluation based on absolute film dosimetry showed greater than 90% pass rate for all cases using a gamma criteria of 3%/1 mm. Conclusions: The authors’ experience demonstrates that the localization accuracy of the frameless image-guided system is comparable to robotic or invasive frame based radiosurgery systems.

Technical Note: Evaluation of the systematic accuracy of a frameless, multiple image modality guided, linear accelerator based stereotactic radiosurgery system

International Nuclear Information System (INIS)

Wen, N.; Snyder, K. C.; Qin, Y.; Li, H.; Siddiqui, M. S.; Chetty, I. J.; Scheib, S. G.; Schmelzer, P.

2016-01-01

Purpose: To evaluate the total systematic accuracy of a frameless, image guided stereotactic radiosurgery system. Methods: The localization accuracy and intermodality difference was determined by delivering radiation to an end-to-end prototype phantom, in which the targets were localized using optical surface monitoring system (OSMS), electromagnetic beacon-based tracking (Calypso®), cone-beam CT, “snap-shot” planar x-ray imaging, and a robotic couch. Six IMRT plans with jaw tracking and a flattening filter free beam were used to study the dosimetric accuracy for intracranial and spinal stereotactic radiosurgery treatment. Results: End-to-end localization accuracy of the system evaluated with the end-to-end phantom was 0.5 ± 0.2 mm with a maximum deviation of 0.9 mm over 90 measurements (including jaw, MLC, and cone measurements for both auto and manual fusion) for single isocenter, single target treatment, 0.6 ± 0.4 mm for multitarget treatment with shared isocenter. Residual setup errors were within 0.1 mm for OSMS, and 0.3 mm for Calypso. Dosimetric evaluation based on absolute film dosimetry showed greater than 90% pass rate for all cases using a gamma criteria of 3%/1 mm. Conclusions: The authors’ experience demonstrates that the localization accuracy of the frameless image-guided system is comparable to robotic or invasive frame based radiosurgery systems.

Multistage stereotactic radiosurgery for large cerebral arteriovenous malformations using the Gamma Knife platform.

Science.gov (United States)

Ding, Chuxiong; Hrycushko, Brian; Whitworth, Louis; Li, Xiang; Nedzi, Lucien; Weprin, Bradley; Abdulrahman, Ramzi; Welch, Babu; Jiang, Steve B; Wardak, Zabi; Timmerman, Robert D

2017-10-01

Radiosurgery is an established technique to treat cerebral arteriovenous malformations (AVMs). Obliteration of larger AVMs (> 10-15 cm 3 or diameter > 3 cm) in a single session is challenging with current radiosurgery platforms due to toxicity. We present a novel technique of multistage stereotactic radiosurgery (SRS) for large intracranial arteriovenous malformations (AVM) using the Gamma Knife system. Eighteen patients with large (> 10-15 cm 3 or diameter > 3 cm) AVMs, which were previously treated using a staged SRS technique on the Cyberknife platform, were retrospectively selected for this study. The AVMs were contoured and divided into 3-8 subtargets to be treated sequentially in a staged approach at half to 4 week intervals. The prescription dose ranged from 15 Gy to 20 Gy, depending on the subtarget number, volume, and location. Gamma Knife plans using multiple collimator settings were generated and optimized. The coordinates of each shot from the initial plan covering the total AVM target were extracted based on their relative positions within the frame system. The shots were regrouped based on their location with respect to the subtarget contours to generate subplans for each stage. The delivery time of each shot for a subtarget was decay corrected with 60 Co for staging the treatment course to generate the same dose distribution as that planned for the total AVM target. Conformality indices and dose-volume analysis were performed to evaluate treatment plans. With the shot redistribution technique, the composite dose for the multistaged treatment of multiple subtargets is equivalent to the initial plan for total AVM target. Gamma Knife plans resulted in an average PTV coverage of 96.3 ± 0.9% and a PITV of 1.23 ± 0.1. The resulting Conformality indices, V 12Gy and R 50 dose spillage values were 0.76 ± 0.05, 3.4 ± 1.8, and 3.1 ± 0.5 respectively. The Gamma Knife system can deliver a multistaged conformal dose to treat large AVMs when correcting for

Early experiences of planning stereotactic radiosurgery using 3D printed models of eyes with uveal melanomas

Directory of Open Access Journals (Sweden)

Furdová A

2017-01-01

Full Text Available Alena Furdová,1 Miron Sramka,2 Andrej Thurzo,3 Adriana Furdová3 1Department of Ophthalmology, Faculty of Medicine, Comenius University, 2Department of Stereotactic Radiosurgery, St Elisabeth Cancer Inst and St Elisabeth University College of Health and Social Work, 3Department of Simulation and Virtual Medical Education, Faculty of Medicine, Comenius University, Bratislava, Slovak Republic Objective: The objective of this study was to determine the use of 3D printed model of an eye with intraocular tumor for linear accelerator-based stereotactic radiosurgery.Methods: The software for segmentation (3D Slicer created virtual 3D model of eye globe with tumorous mass based on tissue density from computed tomography and magnetic resonance imaging data. A virtual model was then processed in the slicing software (Simplify3D® and printed on 3D printer using fused deposition modeling technology. The material that was used for printing was polylactic acid.Results: In 2015, stereotactic planning scheme was optimized with the help of 3D printed model of the patient’s eye with intraocular tumor. In the period 2001–2015, a group of 150 patients with uveal melanoma (139 choroidal melanoma and 11 ciliary body melanoma were treated. The median tumor volume was 0.5 cm3 (0.2–1.6 cm3. The radiation dose was 35.0 Gy by 99% of dose volume histogram.Conclusion: The 3D printed model of eye with tumor was helpful in planning the process to achieve the optimal scheme for irradiation which requires high accuracy of defining the targeted tumor mass and critical structures. Keywords: 3D printing, uveal melanoma, stereotactic radiosurgery, linear accelerator, intraocular tumor, stereotactic planning scheme

Evaluation of Real-time Measurement Liver Tumor's Movement and SynchronyTM System's Accuracy of Radiosurgery using a Robot CyberKnife

International Nuclear Information System (INIS)

Kim, Gha Jung; Shim, Su Jung; Kim, Jeong Ho; Min, Chul Kee; Chung, Weon Kuu

2008-01-01

This study aimed to quantitatively measure the movement of tumors in real-time and evaluate the treatment accuracy, during the treatment of a liver tumor patient, who underwent radiosurgery with a Synchrony Respiratory motion tracking system of a robot CyberKnife. Materials and Methods: The study subjects included 24 liver tumor patients who underwent CyberKnife treatment, which included 64 times of treatment with the Synchrony Respiratory motion tracking system (SynchronyTM). The treatment involved inserting 4 to 6 acupuncture needles into the vicinity of the liver tumor in all the patients using ultrasonography as a guide. A treatment plan was set up using the CT images for treatment planning uses. The position of the acupuncture needle was identified for every treatment time by Digitally Reconstructed Radiography (DRR) prepared at the time of treatment planning and X-ray images photographed in real-time. Subsequent results were stored through a Motion Tracking System (MTS) using the Mtsmain.log treatment file. In this way, movement of the tumor was measured. Besides, the accuracy of radiosurgery using CyberKnife was evaluated by the correlation errors between the real-time positions of the acupuncture needles and the predicted coordinates. Results: The maximum and the average translational movement of the liver tumor were measured 23.5 mm and 13.9±5.5 mm, respectively from the superior to the inferior direction, 3.9 mm and 1.9±0.9 mm, respectively from left to right, and 8.3 mm and 4.9±1.9 mm, respectively from the anterior to the posterior direction. The maximum and the average rotational movement of the liver tumor were measured to be 3.3o and 2.6±1.3o, respectively for X (Left-Right) axis rotation, 4.8o and 2.3±1.0o, respectively for Y (Cranio-Caudal) axis rotation, 3.9o and 2.8±1.1o, respectively for Z (Anterior-Posterior) axis rotation. In addition, the average correlation error, which represents the treatment's accuracy was 1.1±0.7 mm. Conclusion

Evaluation of the uncertainties in the TLD radiosurgery postal dose system

International Nuclear Information System (INIS)

Campos, Luciana Tourinho; Leite, Sandro Passos; Almeida, Carlos Eduardo Veloso de; Magalhães, Luís Alexandre Gonçalves

2017-01-01

Radiosurgery is a single-fraction radiation therapy procedure for treating intracranial lesions using a stereotactic apparatus and multiple narrow beams delivered through noncoplanar isocentric arcs. The Radiological Science Laboratory (LCR/UERJ) operates a postal audit programme in SRT and SRS. The purpose of the programme is to verify the target localization accuracy and the dosimetric conditions of the TPS. The programme works in such a way those TLDs are sent to the centre where they are to be irradiated to a certain dose. The aim of the present work is estimate the uncertainties in the process of dose determination, using experimental data. (author)

Evaluation of the uncertainties in the TLD radiosurgery postal dose system

Energy Technology Data Exchange (ETDEWEB)

Campos, Luciana Tourinho; Leite, Sandro Passos; Almeida, Carlos Eduardo Veloso de; Magalhães, Luís Alexandre Gonçalves, E-mail: tc_luciana@yahoo.com.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

Radiosurgery is a single-fraction radiation therapy procedure for treating intracranial lesions using a stereotactic apparatus and multiple narrow beams delivered through noncoplanar isocentric arcs. The Radiological Science Laboratory (LCR/UERJ) operates a postal audit programme in SRT and SRS. The purpose of the programme is to verify the target localization accuracy and the dosimetric conditions of the TPS. The programme works in such a way those TLDs are sent to the centre where they are to be irradiated to a certain dose. The aim of the present work is estimate the uncertainties in the process of dose determination, using experimental data. (author)

Radiosurgery for Medial Temporal Lobe Epilepsy Resulting from Mesial Temporal Sclerosis.

Science.gov (United States)

Gianaris, Thomas; Witt, Thomas; Barbaro, Nicholas M

2016-01-01

Medial temporal lobe epilepsy associated with mesial temporal sclerosis (MTS) is perhaps the most well-defined epilepsy syndrome that is responsive to structural interventions such as surgery. Several minimally invasive techniques have arisen that provide additional options for the treatment of MTS while potentially avoiding many of open surgery's associated risks. By evading these risks, they also open up treatment options to patients who otherwise are poor surgical candidates. Radiosurgery is one of the most intensively studied of these alternatives and has found a growing role in the treatment of medial temporal lobe epilepsy. Copyright © 2016 Elsevier Inc. All rights reserved.

In vivo dosimetry in radio-surgery using MOSFET and micro MOSFET

International Nuclear Information System (INIS)

Sors, Aurelie

2010-01-01

The author reports a study which aimed at assessing MOSFETs and micro-MOSFETs as in vivo surface dosimeters in 6 MV radio-surgery fixed beams for minimum field sizes of 6 x 6 square millimetres. The developed calibration method is adapted to small beams and MOSFET technology. It allows a reduced number of measurements to perform calibration. Moreover, a new equivalent square formula increases the accuracy of the determination of the actual dose delivered in small beams. Obtained results show that MOSFETs and micro-MOSFETs can be used as in vivo dosimeters when located at the surface

Clinical experience of stereotactic radiosurgery at a linear accelerator for intraocular melanoma.

Science.gov (United States)

Furdova, Alena; Sramka, Miron; Chorvath, Martin; Kralik, Gabriel; Furda, Robert; Gregus, Michal

2017-10-01

Long-term results with linear accelerator LINAC-based stereotactic radiosurgery for intraocular uveal malignant melanoma were assessed. A retrospective study was carried out of patients with uveal melanoma after a 1-day session stereotactic radiosurgery at LINAC in Slovakia. In the period 2001-2015, a group of 150 patients with uveal melanoma (139 choroidal melanoma, 11 ciliary body melanoma) was treated. The median tumor volume at baseline was 0.5 cm (with range from 0.2 to 1.6 cm). Tumors ranged in size from 2.4 to 20.8 mm in basal diameter and from 2.0 to 18.3 mm in thickness. The therapeutic dose was 35.0 Gy by 99% of dose volume histogram. Older age at treatment was correlated with the largest basal tumor diameter, tumor thickness, and TNM stage. The survival after stereotactic irradiation was 96% in 1 year, 93% in 2 years, 84% in 5 years, 80% in 7 years, and 53% in 11 years. In 20 (13.3%) patients, secondary enucleation was necessary because of complications (secondary glaucoma). Enucleation-free interval ranged from 1 to 6 years. The median age at death was lower (65.7 years) for patients who died from metastatic disease than for those who died from any other cause (75.0 years). Survival rates at 5-year intervals and the need for secondary enucleation because of complications after linear accelerator irradiation are comparable to other techniques.

Present situation and prospect of gamma knife radiosurgery for functional brain disorders

International Nuclear Information System (INIS)

Zhang Yongquan; Zhao Xianjun; Liu Wenli

2002-01-01

With the evolution of imaging technology in the past two decades, currently anatomic targets including the trigeminal nerve (for trigeminal neuralgia), the thalamus (for tremor or pain), the cingulate gyrus, anterior internal capsule or amygdala (for pain or psychiatric illness), the globus pallidum (for symptoms of Parkinson's disease), and the hippocampus (for epilepsy) can be precisely located with computerized tomography, magnetic resonance image, single photon emission computerized tomography and positron emission tomography; stereotactic radiosurgery gradually tends to perfection. Gamma knife therapy for nervous functional disorders has become the focus of interest in clinical study

A quality assurance program in stereotactic radiosurgery using the gamma knife unit

International Nuclear Information System (INIS)

Stuecklschweiger, G.F.; Feichtinger, K.

1998-01-01

Because of the large single fraction dose in stereotactic radiosurgery it is important to guarantee a high geometric and dosimetric accuracy. The paper represent the quality assurance program for the Gamma Knife unit at the University Clinic of Neurosurgery in Graz. The program includes the following procedures: Timer control, mechanical radiation isocenter coincidence, trunnion centricity, helmet microswitches test, radiation output and relative helmet factors, dose profile verification, safety interlocks checks and software quality assurance. In summary, the mechanical accuracy and reproducibility of the Gamma Knife unit are [de

Magnetic resonance imaging characteristics and the prediction of outcome of vestibular schwannomas following Gamma Knife radiosurgery.

Science.gov (United States)

Wu, Chih-Chun; Guo, Wan-Yuo; Chung, Wen-Yuh; Wu, Hisu-Mei; Lin, Chung-Jung; Lee, Cheng-Chia; Liu, Kang-Du; Yang, Huai-Che

2017-12-01

OBJECTIVE Gamma Knife surgery (GKS) is a promising treatment modality for patients with vestibular schwannomas (VSs), but a small percentage of patients have persistent postradiosurgical tumor growth. The aim of this study was to determine the clinical and quantitative MRI features of VS as predictors of long-term tumor control after GKS. METHODS The authors performed a retrospective study of all patients with VS treated with GKS using the Leksell Gamma Knife Unit between 2005 and 2013 at their institution. A total of 187 patients who had a minimum of 24 months of clinical and radiological assessment after radiosurgery were included in this study. Those who underwent a craniotomy with tumor removal before and after GKS were excluded. Study patients comprised 85 (45.5%) males and 102 (54.5%) females, with a median age of 52.2 years (range 20.4-82.3 years). Tumor volumes, enhancing patterns, and apparent diffusion coefficient (ADC) values were measured by region of interest (ROI) analysis of the whole tumor by serial MRI before and after GKS. RESULTS The median follow-up period was 60.8 months (range 24-128.9 months), and the median treated tumor volume was 3.54 cm 3 (0.1-16.2 cm 3 ). At last follow-up, imaging studies indicated that 150 tumors (80.2%) showed decreased tumor volume, 20 (10.7%) had stabilized, and 17 (9.1%) continued to grow following radiosurgery. The postradiosurgical outcome was not significantly correlated with pretreatment volumes or postradiosurgical enhancing patterns. Tumors that showed regression within the initial 12 months following radiosurgery were more likely to have a larger volume reduction ratio at last follow-up than those that did not (volume reduction ratio 55% vs 23.6%, respectively; p < 0.001). Compared with solid VSs, cystic VSs were more likely to regress or stabilize in the initial postradiosurgical 6-12-month period and during extended follow-up. Cystic VSs exhibited a greater volume reduction ratio at last follow-up (cystic

Radiosurgery with flattening-filter-free techniques in the treatment of brain metastases. Plan comparison and early clinical evaluation

International Nuclear Information System (INIS)

Rieber, J.; Tonndorf-Martini, E.; Schramm, O.; Rhein, B.; Stefanowicz, S.; Lindel, K.; Debus, J.; Rieken, S.; Kappes, J.; Hoffmann, H.

2016-01-01

Radiosurgical treatment of brain metastases is well established in daily clinical routine. Utilization of flattening-filter-free beams (FFF) may allow for more rapid delivery of treatment doses and improve clinical comfort. Hence, we compared plan quality and efficiency of radiosurgery in FFF mode to FF techniques. Between November 2014 and June 2015, 21 consecutive patients with 25 brain metastases were treated with stereotactic radiosurgery (SRS) in FFF mode. Brain metastases received dose-fractionation schedules of 1 x 20 Gy or 1 x 18 Gy, delivered to the conformally enclosing 80 % isodose. Three patients with critically localized or large (>3 cm) brain metastases were treated with 6 x 5 Gy. Plan quality and efficiency were evaluated by analyzing conformity, dose gradients, dose to healthy brain tissue, treatment delivery time, and number of monitor units. FFF plans were compared to those using the FF method, and early clinical outcome and toxicity were assessed. FFF mode resulted in significant reductions in beam-on time (p [de

Dosimetry and monitoring of X-rays narrow beams produced by linear particle accelerator, for using in radiosurgery

International Nuclear Information System (INIS)

Campos, J.C.F.; Vizeu, D.M.

1987-01-01

The main characteristics of X-rays narrow beams dosimetry and monitoring are examined, aiming the introduction of this system in brain radiosurgery. The non-protocolize detectors are used, once that the detectors used in therapy by megavoltage were projected for dosimetry with an irradiation field above 40 mm diameter. (C.G.C.) [pt

A round-robin gamma stereotactic radiosurgery dosimetry interinstitution comparison of calibration protocols

Energy Technology Data Exchange (ETDEWEB)

Drzymala, R. E., E-mail: drzymala@wustl.edu [Department of Radiation Oncology, Washington University, St. Louis, Missouri 63110 (United States); Alvarez, P. E. [Imaging and Radiation Oncology Core Houston, UT MD Anderson Cancer Center, Houston, Texas 77030 (United States); Bednarz, G. [Radiation Oncology Department, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15232 (United States); Bourland, J. D. [Department of Radiation Oncology, Wake Forest University, Winston-Salem, North Carolina 27157 (United States); DeWerd, L. A. [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Ma, L. [Department of Radiation Oncology, University California San Francisco, San Francisco, California 94143 (United States); Meltsner, S. G. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Neyman, G. [Department of Radiation Oncology, The Cleveland Clinic Foundation, Cleveland, Ohio 44195 (United States); Novotny, J. [Medical Physics Department, Hospital Na Homolce, Prague 15030 (Czech Republic); Petti, P. L. [Gamma Knife Center, Washington Hospital Healthcare System, Fremont, California 94538 (United States); Rivard, M. J. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States); Shiu, A. S. [Department of Radiation Oncology, University of Southern California, Los Angeles, California 90033 (United States); Goetsch, S. J. [San Diego Medical Physics, Inc., La Jolla, California 92037 (United States)

2015-11-15

Purpose: Absorbed dose calibration for gamma stereotactic radiosurgery is challenging due to the unique geometric conditions, dosimetry characteristics, and nonstandard field size of these devices. Members of the American Association of Physicists in Medicine (AAPM) Task Group 178 on Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance have participated in a round-robin exchange of calibrated measurement instrumentation and phantoms exploring two approved and two proposed calibration protocols or formalisms on ten gamma radiosurgery units. The objectives of this study were to benchmark and compare new formalisms to existing calibration methods, while maintaining traceability to U.S. primary dosimetry calibration laboratory standards. Methods: Nine institutions made measurements using ten gamma stereotactic radiosurgery units in three different 160 mm diameter spherical phantoms [acrylonitrile butadiene styrene (ABS) plastic, Solid Water, and liquid water] and in air using a positioning jig. Two calibrated miniature ionization chambers and one calibrated electrometer were circulated for all measurements. Reference dose-rates at the phantom center were determined using the well-established AAPM TG-21 or TG-51 dose calibration protocols and using two proposed dose calibration protocols/formalisms: an in-air protocol and a formalism proposed by the International Atomic Energy Agency (IAEA) working group for small and nonstandard radiation fields. Each institution’s results were normalized to the dose-rate determined at that institution using the TG-21 protocol in the ABS phantom. Results: Percentages of dose-rates within 1.5% of the reference dose-rate (TG-21 + ABS phantom) for the eight chamber-protocol-phantom combinations were the following: 88% for TG-21, 70% for TG-51, 93% for the new IAEA nonstandard-field formalism, and 65% for the new in-air protocol. Averages and standard deviations for dose-rates over all measurements relative to the TG-21 + ABS

3-D dosimetric evaluation of 2.5 mm HD120 multileaf system for intensity modulated stereotactic radiosurgery using optical CT based polymer gel dosimetry

International Nuclear Information System (INIS)

Wuu, C-S; Kessel, Jack; Xu, Y

2009-01-01

A Trilogy TX equipped with a 2.5 mm HD120 multileaf collimator system is available for the treatment of radiosurgery and IMRT. In this study, we evaluated the 3-D dosimetric impact of leaf width on an IMRT radiosurgery plan by comparing the target coverage and the dose gradient around the target, produced from both a 2.5 mm HD120 high-definition MLC system and a 5mm-leaf-width millennium 120 MLC system, using an optical CT based polymer gel dosimetry system. The 2.5 mm MLC improves target conformity and surrounding tissue sparing when compared to that of 5 mm MLC.

Factors influencing local control and survival for patients undergoing stereotactic radiosurgery for intracranial metastases

International Nuclear Information System (INIS)

Suh, John H.; Barnett, Gene H.; Sohn, Jason W.; Fernandez-Vicioso, Eduardo; Kupelian, Patrick A.

1996-01-01

PURPOSE: To identify factors affecting local control and survival for patients undergoing stereotactic radiosurgery for intracranial metastases. MATERIALS AND METHODS: From 3/90-10/95, 99 patients (median age 58, range 29-83; 44 women, 55 men) with asymptomatic or mildly symptomatic intracranial metastases measuring < 4 cm in diameter and ≥ 1 cm from optic chiasm and Karnofsky Performance Status (KPS) ≥ 70 underwent modified linear accelerator-based stereotactic radiosurgery (SRS). Patients characteristics included 20 with recurrent disease, 66 with solitary lesions, and 42 with systemic disease. Forty six patients underwent surgical resection prior to SRS (16 biopsy, 3 subtotal resection (STR), and 21 gross total resection (GTR)). Eighty of 99 patients underwent whole brain radiation treatments (median 4005 cGy/15 fx, range 2200-6000 cGy). A total of 154 lesions were treated with 143 being evaluable on follow-up CT or MRI scans. Radiosurgery parameters (median) were the following: volume 2.8 cc (range 0.1-38 cc) and a peripheral dose of 1700 cGy (range 500-2400 cGy) with normalization to the 80% line (range 50-90%). Survival was measured from the date of SRS. Local control was defined as stabilization or decrease in size of the intracranial lesion(s). RESULTS: The following factors were analyzed with respect to local control and survival: 1) solitary vs. multiple lesions, 2) Age < or ≥ 60, 3) sex, 4) radiosensitive vs. radioresistant (renal cell and melanoma) histologies, 5) recurrent vs. newly diagnosed lesions, 6) KPS (70-80 vs. 90-100), 7) extent of surgery (biopsy vs. STR/GTR), 8) use of whole brain radiation treatments, 9) absence or presence of systemic disease, 10) dose (< or ≥ 1500 cGy) and 11) volume (< or ≥ 3 cc). On univariate analysis, survival was significantly influenced by female sex, presence of solitary lesion, absence of systemic disease, and extent of surgery. On multivariate analysis, female sex (p=0.0037), absence of systemic disease

The application of micro-vacuo-certo-contacting ophthalmophanto in X-ray radiosurgery for tumors in an eyeball.

Science.gov (United States)

Li, Shuying; Wang, Yunyan; Hu, Likuan; Liang, Yingchun; Cai, Jing

2014-11-01

The large errors of routine localization for eyeball tumors restricted X-ray radiosurgery application, just for the eyeball to turn around. To localize the accuracy site, the micro-vacuo-certo-contacting ophthalmophanto (MVCCOP) method was used. Also, the outcome of patients with tumors in the eyeball was evaluated. In this study, computed tomography (CT) localization accuracy was measured by repeating CT scan using MVCCOP to fix the eyeball in radiosurgery. This study evaluated the outcome of the tumors and the survival of the patients by follow-up. The results indicated that the accuracy of CT localization of Brown-Roberts-Wells (BRW) head ring was 0.65 mm and maximum error was 1.09 mm. The accuracy of target localization of tumors in the eyeball using MVCCOP was 0.87 mm averagely, and the maximum error was 1.19 mm. The errors of fixation of the eyeball were 0.84 mm averagely and 1.17 mm maximally. The total accuracy was 1.34 mm, and 95% confidence accuracy was 2.09 mm. The clinical application of this method in 14 tumor patients showed satisfactory results, and all of the tumors showed the clear rims. The site of ten retinoblastomas was decreased significantly. The local control interval of tumors were 6 ∼ 24 months, median of 10.5 months. The survival of ten patients was 7 ∼ 30 months, median of 16.5 months. Also, the tumors were kept stable or shrank in the other four patients with angioma and melanoma. In conclusion, the MVCCOP is suitable and dependable for X-ray radiosurgery for eyeball tumors. The tumor control and survival of patients are satisfactory, and this method can effectively postpone or avoid extirpation of eyeball.

Treatment of arteriovenous malformations with stereotactic radiosurgery employing both magnetic resonance angiography and standard angiography as a database

International Nuclear Information System (INIS)

Petereit, D.; Mehta, M.; Turski, P.; Levin, A.; Strother, C.; Mistretta, C.; Mackie, R.; Gehring, M.; Kubsad, S.; Kinsella, T.

1993-01-01

Twenty-one arteriovenous malformations were prospectively evaluated using magnetic resonance angiography, compare it to stereotactic angiography, employ magnetic resonance angiography in follow-up, and semiquanitfy flow. A correlative evaluation between flow and response to stereotactic radiosurgery was carried out. Phase contrast angiograms were obtained at flow velocities of 400, 200, 100, 60 and 20 cm/sec. The fractionated velocities provided images that selectively demonstrated the arterial and venous components of the arteriovenous malformations. Qualitative assessment of the velocity within the arteriovenous malformations and the presence of fistulae were also determined by multiple velocity images. In addition, 3-dimensional time-of-flight magnetic resonance angiograms were obtained to define the exact size and shape of the nidus. This technique also permitted evaluation of the nidus and feeding arteries for the the presence of low flow aneurysms. Correlation between the two imaging modalities was carried out by subjective and semiquantitative estimation of flow velocity and estimation of nidus size. The following velocity parameters were employed: fast, intermediate, slow, and none. Early analysis suggests that slower flowing arteriovenous malformations may obliterate faster after stereotactic radiosurgery an flow parameters should be employed to predict response. In conclusion, magnetic resonance angiography permits semiquantitative flow velocity assessment and may therefore be superior to stereotactic angiography. An additional advantage of magnetic resonance angiography is the generation of serial transverse images which can replace the conventional CT scan employed for stereotactic radiosurgery treatment planning. A single diagnostic test may therefore be used for diagnosis, radiosurgical treatment planning, follow-up, and treatment selection by identifying patients likely to respond early to radiosurgical management

Pretreatment Predictors of Adverse Radiation Effects After Radiosurgery for Arteriovenous Malformation

International Nuclear Information System (INIS)

Hayhurst, Caroline; Monsalves, Eric; Prooijen, Monique van; Cusimano, Michael; Tsao, May; Menard, Cynthia; Kulkarni, Abhaya V.; Schwartz, Michael; Zadeh, Gelareh

2012-01-01

Purpose: To identify vascular and dosimetric predictors of symptomatic T2 signal change and adverse radiation effects after radiosurgery for arteriovenous malformation, in order to define and validate preexisting risk models. Methods and Materials: A total of 125 patients with arteriovenous malformations (AVM) were treated at our institution between 2005 and 2009. Eighty-five patients have at least 12 months of clinical and radiological follow-up. Any new-onset headaches, new or worsening seizures, or neurological deficit were considered adverse events. Follow-up magnetic resonance images were assessed for new onset T2 signal change and the volume calculated. Pretreatment characteristics and dosimetric variables were analyzed to identify predictors of adverse radiation effects. Results: There were 19 children and 66 adults in the study cohort, with a mean age of 34 (range 6–74). Twenty-three (27%) patients suffered adverse radiation effects (ARE), 9 patients with permanent neurological deficit (10.6%). Of these, 5 developed fixed visual field deficits. Target volume and 12 Gy volume were the most significant predictors of adverse radiation effects on univariate analysis (p 3 , above which the rate of ARE increased dramatically. Multivariate analysis target volume and the absence of prior hemorrhage are the only significant predictors of ARE. The volume of T2 signal change correlates to ARE, but only target volume is predictive of a higher volume of T2 signal change. Conclusions: Target volume and the absence of prior hemorrhage is the most accurate predictor of adverse radiation effects and complications after radiosurgery for AVMs. A high percentage of permanent visual field defects in this series suggest the optic radiation is a critical radiosensitive structure.

Frameless Stereotactic Radiosurgery for Treatment of Multiple Sclerosis-Related Trigeminal Neuralgia.

Science.gov (United States)

Conti, Alfredo; Pontoriero, Antonio; Iatì, Giuseppe; Esposito, Felice; Siniscalchi, Enrico Nastro; Crimi, Salvatore; Vinci, Sergio; Brogna, Anna; De Ponte, Francesco; Germanò, Antonino; Pergolizzi, Stefano; Tomasello, Francesco

2017-07-01

Trigeminal neuralgia (TN) affects 7% of patients with multiple sclerosis (MS). In such patients, TN is difficult to manage either pharmacologically and surgically. Radiosurgical rhizotomy is an effective treatment option. The nonisocentric geometry of radiation beams of CyberKnife introduces new concepts in the treatment of TN. Its efficacy for MS-related TN has not yet been demonstrated. Twenty-seven patients with refractory TN and MS were treated. A nonisocentric beams distribution was chosen; the maximal target dose was 72.5 Gy. The maximal dose to the brainstem was <12 Gy. Effects on pain, medications, sensory disturbance, rate, and time of pain recurrence were analyzed. Median follow-up was 37 (18-72) months. Barrow Neurological Institute pain scale score I-III was achieved in 23/27 patients (85%) within 45 days. Prescription isodose line (80%) accounting for a dose of 58 Gy incorporated an average of 4.85 mm (4-6 mm) of the nerve and mean nerve volume of 26.4 mm 3 (range 20-38 mm 3 ). Seven out of 27 patients (26%) had mild, not bothersome, facial numbness (Barrow Neurological Institute numbness score II). The rate of pain control decreased progressively after the first year, and only 44% of patients retained pain control 4 years later. Frameless radiosurgery can be effectively used to perform retrogasserian rhizotomy. Pain relief was satisfactory and, with our dose/volume constraints, no sensory complications were recorded. Nonetheless, long-term pain control was possible in less than half of the patients. This is a limitation that CyberKnife radiosurgery shares with other techniques in MS patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Tolerance of the Spinal Cord to Stereotactic Radiosurgery: Insights From Hemangioblastomas

International Nuclear Information System (INIS)

Daly, Megan E.; Choi, Clara Y.H.; Gibbs, Iris C.; Adler, John R.; Chang, Steven D.; Lieberson, Robert E.; Soltys, Scott G.

2011-01-01

Purpose: To evaluate spinal cord dose-volume effects, we present a retrospective review of stereotactic radiosurgery (SRS) treatments for spinal cord hemangioblastomas. Methods and Materials: From November 2001 to July 2008, 27 spinal hemangioblastomas were treated in 19 patients with SRS. Seventeen tumors received a single fraction with a median dose of 20 Gy (range, 18-30 Gy). Ten lesions were treated using 18-25 Gy in two to three sessions. Cord volumes receiving 8, 10, 12, 14, 16, 18, 20, 22, and 24 Gy and dose to 10, 100, 250, 500, 1000, and 2000 mm 3 of cord were determined. Multisession treatments were converted to single-fraction biologically effective dose (SFBED). Results: Single-fraction median cord D max was 22.7 Gy (range, 17.8-30.9 Gy). Median V10 was 454 mm 3 (range, 226-3543 mm 3 ). Median dose to 500 mm 3 cord was 9.5 Gy (range, 5.3-22.5 Gy). Fractionated median SFBED 3 cord D max was 14.1 Gy 3 (range, 12.3-19.4 Gy 3 ). Potential toxicities included a Grade 2 unilateral foot drop 5 months after SRS and 2 cases of Grade 1 sensory deficits. The actuarial 3-year local tumor control estimate was 86%. Conclusions: Despite exceeding commonly cited spinal cord dose constraints, SRS for spinal hemangioblastomas is safe and effective. Consistent with animal experiments, these data support a partial-volume tolerance model for the human spinal cord. Because irradiated cord volumes were generally small, application of these data to other clinical scenarios should be made cautiously. Further prospective studies of spinal radiosurgery are needed.

Stereotactic Radiosurgery for Cushing Disease: Results of an International, Multicenter Study.

Science.gov (United States)

Mehta, Gautam U; Ding, Dale; Patibandla, Mohana Rao; Kano, Hideyuki; Sisterson, Nathaniel; Su, Yan-Hua; Krsek, Michal; Nabeel, Ahmed M; El-Shehaby, Amr; Kareem, Khaled A; Martinez-Moreno, Nuria; Mathieu, David; McShane, Brendan; Blas, Kevin; Kondziolka, Douglas; Grills, Inga; Lee, John Y; Martinez-Alvarez, Roberto; Reda, Wael A; Liscak, Roman; Lee, Cheng-Chia; Lunsford, L Dade; Vance, Mary Lee; Sheehan, Jason P

2017-11-01

Cushing disease (CD) due to adrenocorticotropic hormone-secreting pituitary tumors can be a management challenge. To better understand the outcomes of stereotactic radiosurgery (SRS) for CD and define its role in management. International, multicenter, retrospective cohort analysis. Ten medical centers participating in the International Gamma Knife Research Foundation. Patients with CD with >6 months endocrine follow-up. SRS using Gamma Knife radiosurgery. The primary outcome was control of hypercortisolism (defined as normalization of free urinary cortisol). Radiologic response and adverse radiation effects (AREs) were recorded. In total, 278 patients met inclusion criteria, with a mean follow-up of 5.6 years (0.5 to 20.5 years). Twenty-two patients received SRS as a primary treatment of CD. Mean margin dose was 23.7 Gy. Cumulative initial control of hypercortisolism was 80% at 10 years. Mean time to cortisol normalization was 14.5 months. Recurrences occurred in 18% with initial cortisol normalization. Overall, the rate of durable control of hypercortisolism was 64% at 10 years and 68% among patients who received SRS as a primary treatment. AREs included hypopituitarism (25%) and cranial neuropathy (3%). Visual deficits were related to treatment of tumor within the suprasellar cistern (P = 0.01), whereas both visual (P < 0.0001) and nonvisual cranial neuropathy (P = 0.02) were related to prior pituitary irradiation. SRS for CD is well tolerated and frequently results in control of hypercortisolism. However, recurrences can occur. SRS should be considered for patients with persistent hypercortisolism after pituitary surgery and as a primary treatment in those unfit for surgery. Long-term endocrine follow-up is essential after SRS. Copyright © 2017 Endocrine Society

Gamma-knife radiosurgery in the treatment of trigeminal schwannomas

International Nuclear Information System (INIS)

Peker, S.; Bayrakli, F.; Kilic, T.; Pamir, M.N.

2007-01-01

Trigeminal nerve schwannomas account for 0.07 %-0.28 % of all intracranial tumors. Advances in skull base surgery have led to more aggressive resection of these tumors, but surgery may associated with development of new neurological deficits. In this report, we analyse the long-term results 15 patients with newly diagnosed or residual/recurrent trigeminal schwannoma who underwent gamma-knife treatment. During a mean 61 months of follow-up, MRI revealed reduction of tumor size in 13 and no size change in 2 patients. The tumor growth control rate was 100 % and only 1 patient had transient facial numbness and diplopia. For patients with small to moderate size trigeminal schwannomas, gamma-knife radiosurgery is associated with good tumor control and a minimal risk of adverse radiation effects. (author)

Alignment verification in stereotactic radiosurgery with use of graphic arts film

International Nuclear Information System (INIS)

Sweet, J.; Lamba, M.

1990-01-01

This paper evaluates the use of graphic arts film for field alignment verification of linear accelerator-based stereotactic radiosurgery. The characteristic curve was generated for Fuji RO-100 graphic arts film in a standard leaded radiation therapy cassette at 6 MV. The linear portion of the curve and the film contrast are presented and their clinical advantages discussed. The high contrast of this graphic arts film improves visualization of the 5-mm ball bearing (simulated target) in small, circular treatment fields. Comparison with standard port film demonstrates the large linear range of the graphic arts film, which proved useful in visualization of the simulated target within the small, circular treatment field

Gold nanoparticle enhancement of stereotactic radiosurgery for neovascular age-related macular degeneration

Science.gov (United States)

Ngwa, Wilfred; Makrigiorgos, G. Mike; Berbeco, Ross I.

2012-10-01

Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries for people over the age of 50. In this work, the dosimetric feasibility of using gold nanoparticles (AuNP) as radiosensitizers to enhance kilovoltage stereotactic radiosurgery for neovascular AMD is investigated. Microdosimetry calculations at the sub-cellular level were carried out to estimate the radiation dose enhancement to individual nuclei in neovascular AMD endothelial cells (nDEF) due to photon-induced photo-/Auger electrons from x-ray-irradiated AuNP. The nDEF represents the ratio of radiation doses to the endothelial cell nuclei with and without AuNP. The calculations were carried out for a range of feasible AuNP local concentrations using the clinically applicable 100 kVp x-ray beam parameters employed by a commercially available x-ray therapy system. The results revealed nDEF values of 1.30-3.26 for the investigated concentration range of 1-7 mg g-1, respectively. In comparison, for the same concentration range, nDEF values of 1.32-3.40, 1.31-3.33, 1.29-3.19, 1.28-3.12 were calculated for 80, 90, 110 and 120 kVp x-rays, respectively. Meanwhile, calculations as a function of distance from the AuNP showed that the dose enhancement, for 100 kVp, is markedly confined to the targeted neovascular AMD endothelial cells where AuNP are localized. These findings provide impetus for considering the application of AuNP to enhance therapeutic efficacy during stereotactic radiosurgery for neovascular AMD.

Proton beam dosimetry for radiosurgery: implementation of the ICRU Report 59 at the Harvard Cyclotron Laboratory

International Nuclear Information System (INIS)

Newhauser, Wayne D.; Myers, Karla D.; Rosenthal, Stanley J.; Smith, Alfred R.

2002-01-01

Recent proton dosimetry intercomparisons have demonstrated that the adoption of a common protocol, e.g. ICRU Report 59, can lead to improved consistency in absorbed dose determinations. We compared absorbed dose values, measured in the 160 MeV proton radiosurgery beamline at the Harvard Cyclotron Laboratory, based on ionization chamber methods with those from a Faraday cup technique. The Faraday cup method is based on a proton fluence determination that allows the estimation of absorbed dose with the CEMA approximation, under which the dose is equal to the fluence times the mean mass stopping power. The ionization chamber technique employs an air-kerma calibration coefficient for 60 Co radiation and a calculated correction in order to take into account the differences in response to 60 Co and proton beam radiations. The absorbed dose to water, based on a diode measurement calibrated with a Faraday cup technique, is approximately 2% higher than was obtained from an ionization chamber measurement. At the Bragg peak depth, the techniques agree to within their respective uncertainties, which are both approximately 4% (1 standard deviation). The ionization chamber technique exhibited superior reproducibility and was adopted in our standard clinical practice for radiosurgery. (author)

Optimization of dose distribution for the system of linear accelerator-based stereotactic radiosurgery

International Nuclear Information System (INIS)

Suh Taesuk.

1990-01-01

This work addresses a method for obtaining an optimal dose distribution of stereotactic radiosurgery. Since stereotactic radiosurgery utilizes multiple noncoplanar arcs and a three-dimensional dose evaluation technique, many beam parameters and complex optimization criteria are included in the dose optimization. Consequently, a lengthy computation time is required to optimize even the simplest case by a trial and error method. The basic approach presented here is to use both an analytical and an experimental optimization to minimize the dose to critical organs while maintaining a dose shaped to the target. The experimental approach is based on shaping the target volumes using multiple isocenters from dose experience, or on field shaping using a beam's eye view technique. The analytical approach is to adapt computer-aided design optimization to find optimum parameters automatically. Three-dimensional approximate dose models are developed to simulate the exact dose model using a spherical or cylindrical coordinate system. Optimum parameters are found much faster with the use of computer-aided design optimization techniques. The implementation of computer-aided design algorithms with the approximate dose model and the application of the algorithms to several cases are discussed. It is shown that the approximate dose model gives dose distributions similar to those of the exact dose model, which makes the approximate dose model an attractive alternative to the exact dose model, and much more efficient in terms of computer-aided design and visual optimization

Peritumoral Brain Edema after Stereotactic Radiosurgery for Asymptomatic Intracranial Meningiomas: Risks and Pattern of Evolution.

Science.gov (United States)

Hoe, Yeon; Choi, Young Jae; Kim, Jeong Hoon; Kwon, Do Hoon; Kim, Chang Jin; Cho, Young Hyun

2015-10-01

To investigate the risks and pattern of evolution of peritumoral brain edema (PTE) after stereotactic radiosurgery (SRS) for asymptomatic intracranial meningiomas. A retrospective study was conducted on 320 patients (median age 56 years, range 24-87 years) who underwent primary Gamma Knife radiosurgery for asymptomatic meningiomas between 1998 and 2012. The median tumor volume was 2.7 cc (range 0.2-10.5 cc) and the median follow-up was 48 months (range 24-168 months). Volumetric data sets for tumors and PTE on serial MRIs were analyzed. The edema index (EI) was defined as the ratio of the volume of PTE including tumor to the tumor volume, and the relative edema indices (rEIs) were calculated from serial EIs normalized against the baseline EI. Risk factors for PTE were analyzed using logistic regression. Newly developed or increased PTE was noted in 49 patients (15.3%), among whom it was symptomatic in 28 patients (8.8%). Tumor volume larger than 4.2 cc (pmaking on SRS for asymptomatic meningiomas of large volume (>4.2 cc), of hemispheric location, or with pre-treatment PTE. PTE usually develops within months, reaches its maximum degree until a year, and resolves within 2 years after SRS.

Analysis of translational errors in frame-based and frameless cranial radiosurgery using an anthropomorphic phantom

Energy Technology Data Exchange (ETDEWEB)

Almeida, Taynna Vernalha Rocha [Faculdades Pequeno Principe (FPP), Curitiba, PR (Brazil); Cordova Junior, Arno Lotar; Almeida, Cristiane Maria; Piedade, Pedro Argolo; Silva, Cintia Mara da, E-mail: taynnavra@gmail.com [Centro de Radioterapia Sao Sebastiao, Florianopolis, SC (Brazil); Brincas, Gabriela R. Baseggio [Centro de Diagnostico Medico Imagem, Florianopolis, SC (Brazil); Marins, Priscila; Soboll, Danyel Scheidegger [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)

2016-03-15

Objective: To evaluate three-dimensional translational setup errors and residual errors in image-guided radiosurgery, comparing frameless and frame-based techniques, using an anthropomorphic phantom. Materials and Methods: We initially used specific phantoms for the calibration and quality control of the image-guided system. For the hidden target test, we used an Alderson Radiation Therapy (ART)-210 anthropomorphic head phantom, into which we inserted four 5- mm metal balls to simulate target treatment volumes. Computed tomography images were the taken with the head phantom properly positioned for frameless and frame-based radiosurgery. Results: For the frameless technique, the mean error magnitude was 0.22 ± 0.04 mm for setup errors and 0.14 ± 0.02 mm for residual errors, the combined uncertainty being 0.28 mm and 0.16 mm, respectively. For the frame-based technique, the mean error magnitude was 0.73 ± 0.14 mm for setup errors and 0.31 ± 0.04 mm for residual errors, the combined uncertainty being 1.15 mm and 0.63 mm, respectively. Conclusion: The mean values, standard deviations, and combined uncertainties showed no evidence of a significant differences between the two techniques when the head phantom ART-210 was used. (author)

Characteristics of a novel treatment system for linear accelerator-based stereotactic radiosurgery.

Science.gov (United States)

Wen, Ning; Li, Haisen; Song, Kwang; Chin-Snyder, Karen; Qin, Yujiao; Kim, Jinkoo; Bellon, Maria; Gulam, Misbah; Gardner, Stephen; Doemer, Anthony; Devpura, Suneetha; Gordon, James; Chetty, Indrin; Siddiqui, Farzan; Ajlouni, Munther; Pompa, Robert; Hammoud, Zane; Simoff, Michael; Kalkanis, Steven; Movsas, Benjamin; Siddiqui, M Salim

2015-07-08

The purpose of this study is to characterize the dosimetric properties and accuracy of a novel treatment platform (Edge radiosurgery system) for localizing and treating patients with frameless, image-guided stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). Initial measurements of various components of the system, such as a comprehensive assessment of the dosimetric properties of the flattening filter-free (FFF) beams for both high definition (HD120) MLC and conical cone-based treatment, positioning accuracy and beam attenuation of a six degree of freedom (6DoF) couch, treatment head leakage test, and integrated end-to-end accuracy tests, have been performed. The end-to-end test of the system was performed by CT imaging a phantom and registering hidden targets on the treatment couch to determine the localization accuracy of the optical surface monitoring system (OSMS), cone-beam CT (CBCT), and MV imaging systems, as well as the radiation isocenter targeting accuracy. The deviations between the percent depth-dose curves acquired on the new linac-based system (Edge), and the previously published machine with FFF beams (TrueBeam) beyond D(max) were within 1.0% for both energies. The maximum deviation of output factors between the Edge and TrueBeam was 1.6%. The optimized dosimetric leaf gap values, which were fitted using Eclipse dose calculations and measurements based on representative spine radiosurgery plans, were 0.700 mm and 1.000 mm, respectively. For the conical cones, 6X FFF has sharper penumbra ranging from 1.2-1.8 mm (80%-20%) and 1.9-3.8 mm (90%-10%) relative to 10X FFF, which has 1.2-2.2mm and 2.3-5.1mm, respectively. The relative attenuation measurements of the couch for PA, PA (rails-in), oblique, oblique (rails-out), oblique (rails-in) were: -2.0%, -2.5%, -15.6%, -2.5%, -5.0% for 6X FFF and -1.4%, -1.5%, -12.2%, -2.5%, -5.0% for 10X FFF, respectively, with a slight decrease in attenuation versus field size. The systematic

Dosimetry of small circular beams of high energy photons for stereotactic radiosurgery and radiotherapy: the use of small ionization chambers

International Nuclear Information System (INIS)

Mazal, A.; Gaboriauid, G.; Zefkili, S.; Rosenwald, J.C.; Boutaudon, S.; Pontvert, D.

1999-01-01

The irradiation of small targets in the brain in a singe fraction (radiosurgery) or with a fractionated approach (stereotactic radiosurgery) with small beams of photons requires specific conditions to measure and to model the dosimetric data needed for treatment planning. In this work we present the method and materials adopted in our institution since 1988 to perform the dosimetry of high energy (6-23) circular photon beams with diameters ranging from 10 to 40 mm at the isocenter of linear accelerators, and its evolution as new dosimetric material became commercially available. in circular ionization chambers of small dimensions. We want to answer the following questions: Which are the minimal basic data needed to model small circular beams of high energy photons? Can we extrapolate or convert data from conventional data of larger beams? Which are the detectors well adapted for these kind of measurements and for which range of beam sizes?

Dosimetry characteristics of the Leksell gamma knife for stereotactic radiosurgery

International Nuclear Information System (INIS)

Wu, A.; Lindner, G.; Maitz, A.; Smarra, N.; Turco, R.F.; Kalend, A.M.; Lunsford, L.D.; Flickinger, J.C.; Bloomer, W.D.

1988-01-01

Gamma knife radiosurgery refers to the treatment procedure that delivers very high dose to a small brain lesion with 201 highly focused beams of Co-60. The hemispheric array of these multiple sources with the sizes of beams ranging from 4, 8, 14, to 18 mm makes the determination of dosimetry characteristics of the radiation field very complex. This paper describes the structures, operations, and dose characteristics of gamma knife. Dosimetry measurements were made using ion chamber, TLD, diode, and films to calibrate the dose outputs of the combination of 201 beams of 4, 8, 14, or 18 mm in diameter irradiating from various directions. Results of measured isodose distribution and dose profiles for the various diameter beams are also presented

Targeting Accuracy of Image-Guided Radiosurgery for Intracranial Lesions: A Comparison Across Multiple Linear Accelerator Platforms.

Science.gov (United States)

Huang, Yimei; Zhao, Bo; Chetty, Indrin J; Brown, Stephen; Gordon, James; Wen, Ning

2016-04-01

To evaluate the overall positioning accuracy of image-guided intracranial radiosurgery across multiple linear accelerator platforms. A computed tomography scan with a slice thickness of 1.0 mm was acquired of an anthropomorphic head phantom in a BrainLAB U-frame mask. The phantom was embedded with three 5-mm diameter tungsten ball bearings, simulating a central, a left, and an anterior cranial lesion. The ball bearings were positioned to radiation isocenter under ExacTrac X-ray or cone-beam computed tomography image guidance on 3 Linacs: (1) ExacTrac X-ray localization on a Novalis Tx; (2) cone-beam computed tomography localization on the Novalis Tx; (3) cone-beam computed tomography localization on a TrueBeam; and (4) cone-beam computed tomography localization on an Edge. Each ball bearing was positioned 5 times to the radiation isocenter with different initial setup error following the 4 image guidance procedures on the 3 Linacs, and the mean (µ) and one standard deviation (σ) of the residual error were compared. Averaged overall 3 ball bearing locations, the vector length of the residual setup error in mm (µ ± σ) was 0.6 ± 0.2, 1.0 ± 0.5, 0.2 ± 0.1, and 0.3 ± 0.1 on ExacTrac X-ray localization on a Novalis Tx, cone-beam computed tomography localization on the Novalis Tx, cone-beam computed tomography localization on a TrueBeam, and cone-beam computed tomography localization on an Edge, with their range in mm being 0.4 to 1.1, 0.4 to 1.9, 0.1 to 0.5, and 0.2 to 0.6, respectively. The congruence between imaging and radiation isocenters in mm was 0.6 ± 0.1, 0.7 ± 0.1, 0.3 ± 0.1, and 0.2 ± 0.1, for the 4 systems, respectively. Targeting accuracy comparable to frame-based stereotactic radiosurgery can be achieved with image-guided intracranial stereotactic radiosurgery treatment. © The Author(s) 2015.

Toxicity of Gamma Knife Radiosurgery in the Treatment of Intracranial Tumors in Patients With Collagen Vascular Diseases or Multiple Sclerosis

International Nuclear Information System (INIS)

Lowell, Dot; Tatter, Stephen B.; Bourland, J. Daniel; Guzman, Allan F. de; Ekstrand, Kenneth E.; Ellis, Thomas L.; Lovato, James F.; McMullen, Kevin P.; Munley, Michael T.; Shaw, Edward G.; Urbanic, James J.; Chan, Michael D.

2011-01-01

Purpose: To assess toxicity in patients with either a collagen vascular disease (CVD) or multiple sclerosis (MS) treated with intracranial radiosurgery. Methods and Materials: Between January 2004 and April 2009, 6 patients with MS and 14 patients with a CVD were treated with Gamma Knife radiosurgery (GKRS) for intracranial tumors. Treated lesions included 15 total brain metastases in 7 patients, 11 benign brain tumors, 1 low grade glioma, and 1 cavernous malformation. Toxicities were graded by the Radiation Therapy Oncology Group Acute/Late Radiation Morbidity Scoring Criteria. “Rare toxicities” were characterized as those reported in the scientific literature at an incidence of 3 (range, 0.14–7.8 cm 3 ). Of the 14 patients with CVD, none experienced a Grade 3 or 4 toxicity or a toxicity characterized as rare. Of the 6 patients with MS, 3 experienced rare toxicities, and two of these were Grade 3 toxicities. Rare complications included a patient experiencing both communicating hydrocephalus and facial nerve palsy, as well as 2 additional patients with motor cranial nerve palsy. High-grade toxicities included the patient with an acoustic neuroma requiring ventriculoperitoneal shunt placement for obstructive hydrocephalus, and 1 patient with a facial nerve schwannoma who experienced permanent facial nerve palsy. Interval between radiosurgery and high-grade toxicities ranged from 1 week to 4 months. Conclusions: Our series suggests that patients with MS who receive GKRS may be at increased risk of rare and high-grade treatment-related toxicity. Given the time course of toxicity, treatment-related edema or demyelination represent potential mechanisms.

Stereotactic radiosurgery for acoustic neuroma: a Canadian perspective

International Nuclear Information System (INIS)

Ross, I.B.; Tator, C.H.

1998-01-01

Stereotactically delivered radiation is now an accepted treatment for patients with acoustic neuroma. In some cases, patient preference may be the reason for its selection, while in others neurosurgeons may select it for patients who are elderly or have significant risk factors for conventional surgery. The majority of patients with acoustic neuroma treatment with stereotactic radiosurgery have been treated with the Gamma Knife, with follow ups of over 25 years in some instances. Other radiosurgical modalities utilizing the linear accelerator have been developed and appear promising, but there is no long-term: follow up. Canada does not possess a Gamma Knife facility, and its government-funded hospital and medical insurance agencies have made it difficult for patients to obtain reimbursement for Gamma Knife treatments in other countries. We review the literature to date on the various forms of radiation treatment for acoustic neuroma and discuss the current issues facing physicians and patients in Canada who wish to obtain their treatment of choice. (author)

Evaluation of Real-time Measurement Liver Tumor's Movement and SynchronyTM System's Accuracy of Radiosurgery using a Robot CyberKnife

Energy Technology Data Exchange (ETDEWEB)

Kim, Gha Jung; Shim, Su Jung; Kim, Jeong Ho; Min, Chul Kee; Chung, Weon Kuu [Konyang University College of Medicine, Daejeon (Korea, Republic of)

2008-12-15

This study aimed to quantitatively measure the movement of tumors in real-time and evaluate the treatment accuracy, during the treatment of a liver tumor patient, who underwent radiosurgery with a Synchrony Respiratory motion tracking system of a robot CyberKnife. Materials and Methods: The study subjects included 24 liver tumor patients who underwent CyberKnife treatment, which included 64 times of treatment with the Synchrony Respiratory motion tracking system (SynchronyTM). The treatment involved inserting 4 to 6 acupuncture needles into the vicinity of the liver tumor in all the patients using ultrasonography as a guide. A treatment plan was set up using the CT images for treatment planning uses. The position of the acupuncture needle was identified for every treatment time by Digitally Reconstructed Radiography (DRR) prepared at the time of treatment planning and X-ray images photographed in real-time. Subsequent results were stored through a Motion Tracking System (MTS) using the Mtsmain.log treatment file. In this way, movement of the tumor was measured. Besides, the accuracy of radiosurgery using CyberKnife was evaluated by the correlation errors between the real-time positions of the acupuncture needles and the predicted coordinates. Results: The maximum and the average translational movement of the liver tumor were measured 23.5 mm and 13.9{+-}5.5 mm, respectively from the superior to the inferior direction, 3.9 mm and 1.9{+-}0.9 mm, respectively from left to right, and 8.3 mm and 4.9{+-}1.9 mm, respectively from the anterior to the posterior direction. The maximum and the average rotational movement of the liver tumor were measured to be 3.3o and 2.6{+-}1.3o, respectively for X (Left-Right) axis rotation, 4.8o and 2.3{+-}1.0o, respectively for Y (Cranio-Caudal) axis rotation, 3.9o and 2.8{+-}1.1o, respectively for Z (Anterior-Posterior) axis rotation. In addition, the average correlation error, which represents the treatment's accuracy was 1

Radiotherapy beyond cancer: Target localization in real-time MRI and treatment planning for cardiac radiosurgery

International Nuclear Information System (INIS)

Ipsen, S.; Blanck, O.; Rades, D.; Oborn, B.; Bode, F.; Liney, G.; Hunold, P.; Schweikard, A.; Keall, P. J.

2014-01-01

Purpose: Atrial fibrillation (AFib) is the most common cardiac arrhythmia that affects millions of patients world-wide. AFib is usually treated with minimally invasive, time consuming catheter ablation techniques. While recently noninvasive radiosurgery to the pulmonary vein antrum (PVA) in the left atrium has been proposed for AFib treatment, precise target location during treatment is challenging due to complex respiratory and cardiac motion. A MRI linear accelerator (MRI-Linac) could solve the problems of motion tracking and compensation using real-time image guidance. In this study, the authors quantified target motion ranges on cardiac magnetic resonance imaging (MRI) and analyzed the dosimetric benefits of margin reduction assuming real-time motion compensation was applied. Methods: For the imaging study, six human subjects underwent real-time cardiac MRI under free breathing. The target motion was analyzed retrospectively using a template matching algorithm. The planning study was conducted on a CT of an AFib patient with a centrally located esophagus undergoing catheter ablation, representing an ideal case for cardiac radiosurgery. The target definition was similar to the ablation lesions at the PVA created during catheter treatment. Safety margins of 0 mm (perfect tracking) to 8 mm (untracked respiratory motion) were added to the target, defining the planning target volume (PTV). For each margin, a 30 Gy single fraction IMRT plan was generated. Additionally, the influence of 1 and 3 T magnetic fields on the treatment beam delivery was simulated using Monte Carlo calculations to determine the dosimetric impact of MRI guidance for two different Linac positions. Results: Real-time cardiac MRI showed mean respiratory target motion of 10.2 mm (superior–inferior), 2.4 mm (anterior–posterior), and 2 mm (left–right). The planning study showed that increasing safety margins to encompass untracked respiratory motion leads to overlapping structures even in the

Radiotherapy beyond cancer: Target localization in real-time MRI and treatment planning for cardiac radiosurgery

Energy Technology Data Exchange (ETDEWEB)

Ipsen, S. [Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Sydney, New South Wales 2006, Australia and Institute for Robotics and Cognitive Systems, University of Luebeck, Luebeck 23562 (Germany); Blanck, O.; Rades, D. [Department of Radiation Oncology, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck, Luebeck 23562 (Germany); Oborn, B. [Illawarra Cancer Care Centre (ICCC), Wollongong, New South Wales 2500, Australia and Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales 2500 (Australia); Bode, F. [Medical Department II, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck, Luebeck 23562 (Germany); Liney, G. [Ingham Institute for Applied Medical Research, Liverpool Hospital, Liverpool, New South Wales 2170 (Australia); Hunold, P. [Department of Radiology and Nuclear Medicine, University of Luebeck and University Medical Center Schleswig-Holstein, Campus Luebeck, Luebeck 23562 (Germany); Schweikard, A. [Institute for Robotics and Cognitive Systems, University of Luebeck, Luebeck 23562 (Germany); Keall, P. J., E-mail: paul.keall@sydney.edu.au [Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Sydney, New South Wales 2006 (Australia)

2014-12-15

Purpose: Atrial fibrillation (AFib) is the most common cardiac arrhythmia that affects millions of patients world-wide. AFib is usually treated with minimally invasive, time consuming catheter ablation techniques. While recently noninvasive radiosurgery to the pulmonary vein antrum (PVA) in the left atrium has been proposed for AFib treatment, precise target location during treatment is challenging due to complex respiratory and cardiac motion. A MRI linear accelerator (MRI-Linac) could solve the problems of motion tracking and compensation using real-time image guidance. In this study, the authors quantified target motion ranges on cardiac magnetic resonance imaging (MRI) and analyzed the dosimetric benefits of margin reduction assuming real-time motion compensation was applied. Methods: For the imaging study, six human subjects underwent real-time cardiac MRI under free breathing. The target motion was analyzed retrospectively using a template matching algorithm. The planning study was conducted on a CT of an AFib patient with a centrally located esophagus undergoing catheter ablation, representing an ideal case for cardiac radiosurgery. The target definition was similar to the ablation lesions at the PVA created during catheter treatment. Safety margins of 0 mm (perfect tracking) to 8 mm (untracked respiratory motion) were added to the target, defining the planning target volume (PTV). For each margin, a 30 Gy single fraction IMRT plan was generated. Additionally, the influence of 1 and 3 T magnetic fields on the treatment beam delivery was simulated using Monte Carlo calculations to determine the dosimetric impact of MRI guidance for two different Linac positions. Results: Real-time cardiac MRI showed mean respiratory target motion of 10.2 mm (superior–inferior), 2.4 mm (anterior–posterior), and 2 mm (left–right). The planning study showed that increasing safety margins to encompass untracked respiratory motion leads to overlapping structures even in the

Radiotherapy beyond cancer: target localization in real-time MRI and treatment planning for cardiac radiosurgery.

Science.gov (United States)

Ipsen, S; Blanck, O; Oborn, B; Bode, F; Liney, G; Hunold, P; Rades, D; Schweikard, A; Keall, P J

2014-12-01

Atrial fibrillation (AFib) is the most common cardiac arrhythmia that affects millions of patients world-wide. AFib is usually treated with minimally invasive, time consuming catheter ablation techniques. While recently noninvasive radiosurgery to the pulmonary vein antrum (PVA) in the left atrium has been proposed for AFib treatment, precise target location during treatment is challenging due to complex respiratory and cardiac motion. A MRI linear accelerator (MRI-Linac) could solve the problems of motion tracking and compensation using real-time image guidance. In this study, the authors quantified target motion ranges on cardiac magnetic resonance imaging (MRI) and analyzed the dosimetric benefits of margin reduction assuming real-time motion compensation was applied. For the imaging study, six human subjects underwent real-time cardiac MRI under free breathing. The target motion was analyzed retrospectively using a template matching algorithm. The planning study was conducted on a CT of an AFib patient with a centrally located esophagus undergoing catheter ablation, representing an ideal case for cardiac radiosurgery. The target definition was similar to the ablation lesions at the PVA created during catheter treatment. Safety margins of 0 mm (perfect tracking) to 8 mm (untracked respiratory motion) were added to the target, defining the planning target volume (PTV). For each margin, a 30 Gy single fraction IMRT plan was generated. Additionally, the influence of 1 and 3 T magnetic fields on the treatment beam delivery was simulated using Monte Carlo calculations to determine the dosimetric impact of MRI guidance for two different Linac positions. Real-time cardiac MRI showed mean respiratory target motion of 10.2 mm (superior-inferior), 2.4 mm (anterior-posterior), and 2 mm (left-right). The planning study showed that increasing safety margins to encompass untracked respiratory motion leads to overlapping structures even in the ideal scenario, compromising

SU-E-T-453: Optimization of Dose Gradient for Gamma Knife Radiosurgery.

Science.gov (United States)

Sheth, N; Chen, Y; Yang, J

2012-06-01

The goals of stereotactic radiosurgery (SRS) are the ablation of target tissue and sparing of critical normal tissue. We develop tools to aid in the selection of collimation and prescription (Rx) isodose line to optimize the dose gradient for single isocenter intracranial stereotactic radiosurgery (SRS) with GammaKnife 4C utilizing the updated physics data in GammaPlan v10.1. Single isocenter intracranial SRS plans were created to treat the center of a solid water anthropomorphism head phantom for each GammaKnife collimator (4 mm, 8 mm, 14 mm, and 18 mm). The dose gradient, defined as the difference of effective radii of spheres equal to half and full Rx volumes, and Rx treatment volume was analyzed for isodoses from 99% to 20% of Rx. The dosimetric data on Rx volume and dose gradient vs. Rx isodose for each collimator was compiled into an easy to read nomogram as well as plotted graphically. The 4, 8, 14, and 18 mm collimators have the sharpest dose gradient at the 64%, 70%, 76%, and 77% Rx isodose lines, respectively. This corresponds to treating 4.77 mm, 8.86 mm, 14.78 mm, and 18.77 mm diameter targets with dose gradients radii of 1.06 mm, 1.63 mm, 2.54 mm, and 3.17 mm, respectively. We analyzed the dosimetric data for the most recent version of GammaPlan treatment planning software to develop tools that when applied clinically will aid in the selection of a collimator and Rx isodose line for optimal dose gradient and target coverage for single isocenter intracranial SRS with GammaKnife 4C. © 2012 American Association of Physicists in Medicine.

Magnetic resonance spectroscopic study of radiogenic changes after radiosurgery of cerebral arteriovenous malformations with implications for the differential diagnosis of radionecrosis

International Nuclear Information System (INIS)

Boström, Jan; Hadizadeh, Dariusch R; Block, Wolfgang; Willinek, Winfried; Schild, Hans H; Träber, Frank

2013-01-01

The incidence of radionecrosis after radiosurgery is 5–20%. That radionecrosis after radiosurgery may be confused with a malignant tumor is a known phenomenon and problem. Three similarly treated patients with cAVM, 1 patient with symptomatic radionecrosis and 2 patients with normal post-radiation MRI changes, were selected and studied in detail with magnetic resonance imaging (MRI), magnetic resonance angiography (MRA), and magnetic resonance spectroscopy (MRS). 2 cAVM were located in eloquent locations and were classified as Spetzler-Martin grade (SM) III such that interdisciplinary radiosurgery was recommended; a third patient with a left frontal SM II cAVM refused surgery. 1 patient was male, and 2 were female. The patient’s ages ranged from 38 to 62 years (median, 39 years). The nidus volume (= planning target volume = PTV) ranged from 2.75 to 6.89 ccm (median, 6.41 ccm). The single dose was 20 Gy at the isocenter of the PTV encompassing the 80 – 90% isodose. The median follow-up period was 20 months (range, 16 – 84 months). Toxicities were evaluated with the Common Terminology Criteria (CTC) for adverse events version 3.0. No patient suffered a bleeding from cAVM during the study period. A complete nidus occlusion was shown in all patients with time-resolved MRA. All patients showed radiogenic MRI changes, 1 patient showed excessive radionecrosis. This patient was oligosymptomatic and under temporary corticoid therapy symptoms resolved completely. Following patterns associated with radionecrosis in the MRS studies were identified in our collective: • 2D spectroscopic imaging (2D-SI) revealed much lower concentrations of metabolites in the lesion as compared to contralateral healthy tissue in all patients. • Whereas regions with regular post-radiosurgery effects showed almost normal levels of Cho and a Cho/Cr ratio < 2.0, regions with radionecrosis were characterized by increased lipid levels and a Cho/Cr ratio > 2.0 in conjunction with decreased

A modification to the Gill-Thomas-Cosman (GTC) head frame for stereotactic radiosurgery of head and neck and cervical spine sites

International Nuclear Information System (INIS)

Qian, G.; Hasala, P.; Rashid, H.; Costantino, T.; Cangiane, L.; Lombardi, E.; Arbit, E; Lederman, G.

1996-01-01

PURPOSE/OBJECTIVE: Fractionated Stereotactic Radiosurgery (FSR) is used primarily to treat intracranial lesions. Many tumors which arise at or inferior to the base of skull and about the cervical spine area were not amenable to radiosurgery. Presented is a modification to the GTC head frame which permits stereotactic radiosurgery to be directed at head and neck tumors with accurate reproducible precision. MATERIALS AND METHODS: The original GTC head frame has two fixation points; an anterior individualized dental impression and a posterior occipital plate with a mold contoured to the occipital pertuberance. The height of the occipital plate is adjustable in its vertical plane. However, the position of the dental piece is fixed and, therefore, limits treatment to regions superior. Treatment of head and neck and cervical spine tumors has been accomplished with a modification of the dental apparatus. Presented is our new device; a bracket extension which attaches to the dental piece and allows the head frame to be lowered to multiple desired positions. The occipital plate is elevated accordingly to support the occipital pertuberance. The depth helmet is also modified for quality assurance. A Rando phantom was used to test the accuracy and reproducibility of the new equipment. Bracket extensions lowering the head frame by 3 cm and 8 cm, respectively, were tested for accuracy of relocation on the Rando Phantom. Each extension was tested 20 times and for each individual test 18 depth helmet positions were obtained. RESULTS: The standard deviation of the modified head frame for each depth helmet measurement ranged from 0.05 to 0.35mm (mean 0.20) as compared to the standard deviation for the original GTC head frame which was 0.13 to 0.34mm (mean 0.24). The new device maintains the accuracy and reproducibility of the original GTC head frame. CONCLUSION: The GTC relocatable head frame for FSR has been modified to treat tumors of the head and neck and cervical spine sites

SU-E-J-25: End-To-End (E2E) Testing On TomoHDA System Using a Real Pig Head for Intracranial Radiosurgery

Energy Technology Data Exchange (ETDEWEB)

Corradini, N; Leick, M; Bonetti, M; Negretti, L [Clinica Luganese, Radiotherapy Center, Lugano (Switzerland)

2015-06-15

Purpose: To determine the MVCT imaging uncertainty on the TomoHDA system for intracranial radiosurgery treatments. To determine the end-to-end (E2E) overall accuracy of the TomoHDA system for intracranial radiosurgery. Methods: A pig head was obtained from the butcher, cut coronally through the brain, and preserved in formaldehyde. The base of the head was fixed to a positioning plate allowing precise movement, i.e. translation and rotation, in all 6 axes. A repeatability test was performed on the pig head to determine uncertainty in the image bone registration algorithm. Furthermore, the test studied images with MVCT slice thicknesses of 1 and 3 mm in unison with differing scan lengths. A sensitivity test was performed to determine the registration algorithm’s ability to find the absolute position of known translations/rotations of the pig head. The algorithm’s ability to determine absolute position was compared against that of manual operators, i.e. a radiation therapist and radiation oncologist. Finally, E2E tests for intracranial radiosurgery were performed by measuring the delivered dose distributions within the pig head using Gafchromic films. Results: The repeatability test uncertainty was lowest for the MVCTs of 1-mm slice thickness, which measured less than 0.10 mm and 0.12 deg for all axes. For the sensitivity tests, the bone registration algorithm performed better than human eyes and a maximum difference of 0.3 mm and 0.4 deg was observed for the axes. E2E test results in absolute position difference measured 0.03 ± 0.21 mm in x-axis and 0.28 ± 0.18 mm in y-axis. A maximum difference of 0.32 and 0.66 mm was observed in x and y, respectively. The average peak dose difference between measured and calculated dose was 2.7 cGy or 0.4%. Conclusion: Our tests using a pig head phantom estimate the TomoHDA system to have a submillimeter overall accuracy for intracranial radiosurgery.

SU-E-J-25: End-To-End (E2E) Testing On TomoHDA System Using a Real Pig Head for Intracranial Radiosurgery

International Nuclear Information System (INIS)

Corradini, N; Leick, M; Bonetti, M; Negretti, L

2015-01-01

Purpose: To determine the MVCT imaging uncertainty on the TomoHDA system for intracranial radiosurgery treatments. To determine the end-to-end (E2E) overall accuracy of the TomoHDA system for intracranial radiosurgery. Methods: A pig head was obtained from the butcher, cut coronally through the brain, and preserved in formaldehyde. The base of the head was fixed to a positioning plate allowing precise movement, i.e. translation and rotation, in all 6 axes. A repeatability test was performed on the pig head to determine uncertainty in the image bone registration algorithm. Furthermore, the test studied images with MVCT slice thicknesses of 1 and 3 mm in unison with differing scan lengths. A sensitivity test was performed to determine the registration algorithm’s ability to find the absolute position of known translations/rotations of the pig head. The algorithm’s ability to determine absolute position was compared against that of manual operators, i.e. a radiation therapist and radiation oncologist. Finally, E2E tests for intracranial radiosurgery were performed by measuring the delivered dose distributions within the pig head using Gafchromic films. Results: The repeatability test uncertainty was lowest for the MVCTs of 1-mm slice thickness, which measured less than 0.10 mm and 0.12 deg for all axes. For the sensitivity tests, the bone registration algorithm performed better than human eyes and a maximum difference of 0.3 mm and 0.4 deg was observed for the axes. E2E test results in absolute position difference measured 0.03 ± 0.21 mm in x-axis and 0.28 ± 0.18 mm in y-axis. A maximum difference of 0.32 and 0.66 mm was observed in x and y, respectively. The average peak dose difference between measured and calculated dose was 2.7 cGy or 0.4%. Conclusion: Our tests using a pig head phantom estimate the TomoHDA system to have a submillimeter overall accuracy for intracranial radiosurgery

Silent Corticotroph Adenomas After Stereotactic Radiosurgery: A Case–Control Study

International Nuclear Information System (INIS)

Xu, Zhiyuan; Ellis, Scott; Lee, Cheng-Chia; Starke, Robert M.; Schlesinger, David; Lee Vance, Mary; Lopes, M. Beatriz; Sheehan, Jason

2014-01-01

Purpose: To investigate the safety and effectiveness of stereotactic radiosurgery (SRS) in patients with a silent corticotroph adenoma (SCA) compared with patients with other subtypes of non–adrenocorticotropic hormone staining nonfunctioning pituitary adenoma (NFA). Methods and Materials: The clinical features and outcomes of 104 NFA patients treated with SRS in our center between September 1994 and August 2012 were evaluated. Among them, 34 consecutive patients with a confirmatory SCA were identified. A control group of 70 patients with other subtypes of NFA were selected for review based on comparable baseline features, including sex, age at the time of SRS, tumor size, margin radiation dose to the tumor, and duration of follow-up. Results: The median follow-up after SRS was 56 months (range, 6-200 months). No patients with an SCA developed Cushing disease during the follow-up. Tumor control was achieved in 21 of 34 patients (62%) in the SCA group, compared with 65 of 70 patients (93%) in the NFA group. The median progression-free survival (PFS) was 58 months in the SCA group. The actuarial PFS was 73%, 46%, and 31% in the SCA group and was 94%, 87%, and 87% in the NFA group at 3, 5, and 8 years, respectively. Silent corticotroph adenomas treated with a dose of ≥17 Gy exhibited improved PFS. New-onset loss of pituitary function developed in 10 patients (29%) in the SCA group, whereas it occurred in 18 patients (26%) in the NFA group. Eight patients (24%) in the SCA group experienced worsening of a visual field deficit or visual acuity attributed to the tumor progression, as did 6 patients (9%) in the NFA group. Conclusion: Silent corticotroph adenomas exhibited a more aggressive course with a higher progression rate than other subtypes of NFAs. Stereotactic radiosurgery is an important adjuvant treatment for control of tumor growth. Increased radiation dose may lead to improved tumor control in SCA patients

Silent Corticotroph Adenomas After Stereotactic Radiosurgery: A Case–Control Study

Energy Technology Data Exchange (ETDEWEB)

Xu, Zhiyuan; Ellis, Scott; Lee, Cheng-Chia; Starke, Robert M. [Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia (United States); Schlesinger, David [Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia (United States); Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia (United States); Lee Vance, Mary [Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia (United States); Department of Internal Medicine, University of Virginia, Charlottesville, Virginia (United States); Lopes, M. Beatriz [Division of Neuropathology, University of Virginia, Charlottesville, Virginia (United States); Sheehan, Jason, E-mail: jsheehan@virginia.edu [Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia (United States); Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia (United States)

2014-11-15

Purpose: To investigate the safety and effectiveness of stereotactic radiosurgery (SRS) in patients with a silent corticotroph adenoma (SCA) compared with patients with other subtypes of non–adrenocorticotropic hormone staining nonfunctioning pituitary adenoma (NFA). Methods and Materials: The clinical features and outcomes of 104 NFA patients treated with SRS in our center between September 1994 and August 2012 were evaluated. Among them, 34 consecutive patients with a confirmatory SCA were identified. A control group of 70 patients with other subtypes of NFA were selected for review based on comparable baseline features, including sex, age at the time of SRS, tumor size, margin radiation dose to the tumor, and duration of follow-up. Results: The median follow-up after SRS was 56 months (range, 6-200 months). No patients with an SCA developed Cushing disease during the follow-up. Tumor control was achieved in 21 of 34 patients (62%) in the SCA group, compared with 65 of 70 patients (93%) in the NFA group. The median progression-free survival (PFS) was 58 months in the SCA group. The actuarial PFS was 73%, 46%, and 31% in the SCA group and was 94%, 87%, and 87% in the NFA group at 3, 5, and 8 years, respectively. Silent corticotroph adenomas treated with a dose of ≥17 Gy exhibited improved PFS. New-onset loss of pituitary function developed in 10 patients (29%) in the SCA group, whereas it occurred in 18 patients (26%) in the NFA group. Eight patients (24%) in the SCA group experienced worsening of a visual field deficit or visual acuity attributed to the tumor progression, as did 6 patients (9%) in the NFA group. Conclusion: Silent corticotroph adenomas exhibited a more aggressive course with a higher progression rate than other subtypes of NFAs. Stereotactic radiosurgery is an important adjuvant treatment for control of tumor growth. Increased radiation dose may lead to improved tumor control in SCA patients.

The effects of pentoxifylline on the survival of human glioma cells with continuous and intermittent stereotactic radiosurgery irradiation

International Nuclear Information System (INIS)

Eley, Kerry W.; Benedict, Stanley H.; Chung, Theodore D.K.; Kavanagh, Brian D.; Broaddus, William C.; Schmidt-Ullrich, Rupert K.A.; Lin, P.-S.

2002-01-01

Purpose: In linac-based stereotactic radiosurgery, treatment is delivered intermittently via multiple individual small radiotherapy arcs. The time lapses between the individual arcs permit greater damage repair and increased tumor cell survival in comparison with continuous irradiation. Because pentoxifylline (PTX) has been reported to prevent radiation-induced cell cycle arrest at the G2/M checkpoint, where damage repair is critically linked to cell survival, we hypothesized that PTX would exert a favorable radiosensitization effect by reducing the recovery observed during intermittent stereotactic radiosurgery. Methods and Materials: The human glioma cell line T98G was used to study the effects of continuous vs. intermittent irradiation with or without PTX. Cell cycle patterns were studied using flow cytometry. Clonogenic assays of single cells and spheroid outgrowth assays provided a quantitative measure of PTX-mediated radiosensitization. The PTX effect upon cells in low oxygen conditions was also studied in vitro after enzymatic oxygen scavenging. Results: Flow Cytometry: T98G cells exposed to both continuous and intermittent irradiation exhibit similar arrest at the G2/M checkpoint. The addition of 2 mM PTX significantly reduced the radiation-induced G2/M block in both irradiation schemes. Clonogenic Assays: The same PTX concentration applied before a continuous dose of 12 Gy, two intermittent doses of 6 Gy, or three intermittent doses of 4 Gy, all given within a 1-h interval, consistently caused radiosensitization. The drug enhancement ratios for PTX were 1.5, 2.7, and 6.0 for the continuous and two different intermittent dose schedules, respectively. Adding PTX after irradiation yielded lower enhancement ratios than pre-irradiation application. A similar pattern was observed after total doses of 4, 6, 9, or 12 Gy, as well. In low oxygen conditions, PTX was seen to have the same effects as in normoxic conditions. Spheroid Outgrowth Assays: The in vitro PTX

Definition of AVM nidus for radiosurgery using segmentation tools

International Nuclear Information System (INIS)

Baker, E.H.; Mehta, M.P.; Sorenson, J.A.

1995-01-01

Purpose/Objective: The complex 3-D anatomy of an AVM nidus is very difficult to appreciate and reconstruct using conventional angiography. MR angiography (MRA) is increasingly being utilized to assist in better defining the nidus. There is, however, considerable operator-dependent bias in determining the true extent of the nidus, with any imaging technique. The generic problem of dividing an image into meaningful regions is known as image segmentation. We have developed several image segmentation tools for our 3-D treatment planning software and have applied these tools to attempt to improve nidus localization. Materials and Methods: Five AVM patients from our archives who had both MRI and MRA images prior to radiosurgery were evaluated. These patients were studied with a spin-echo sequence with density-weighted anatomical images of the entire brain and a time-of-flight (TOF) sequence with vascular images of the AVM. The density-weighted images have good contrast among stationary tissues such as grey matter and white matter, but all vessels are black 'flow voids'. On the TOF images, vessels have a signal that is roughly proportional to the velocity of the flow within them; fast-moving blood is very bright, while slow-moving blood is similar to stationary tissues. By applying segmentation techniques to registered image sets, we were able to use information in density-weighted images to distinguish vessels from non-vessels, and information in TOF images to distinguish fast-flowing blood in the feeder vessels from slower-flowing blood in the nidus. Results: Since this work is in progress, image acquisition parameters varied, and some TOF images had poor signal-to-noise. In spite of this, we were able to segment the AVM nidus in all cases and display it in a readily-distinguishable manner. The nidus velocity appeared to be moderate in three cases, mixed in one, and slow in another. In the latter case, the slow velocity produced some overlap with draining veins. In all

Dose verification to cochlea during gamma knife radiosurgery of acoustic schwannoma using MOSFET dosimeter.

Science.gov (United States)

Sharma, Sunil D; Kumar, Rajesh; Akhilesh, Philomina; Pendse, Anil M; Deshpande, Sudesh; Misra, Basant K

2012-01-01

Dose verification to cochlea using metal oxide semiconductor field effect transistor (MOSFET) dosimeter using a specially designed multi slice head and neck phantom during the treatment of acoustic schwannoma by Gamma Knife radiosurgery unit. A multi slice polystyrene head phantom was designed and fabricated for measurement of dose to cochlea during the treatment of the acoustic schwannoma. The phantom has provision to position the MOSFET dosimeters at the desired location precisely. MOSFET dosimeters of 0.2 mm x 0.2 mm x 0.5 μm were used to measure the dose to the cochlea. CT scans of the phantom with MOSFETs in situ were taken along with Leksell frame. The treatment plans of five patients treated earlier for acoustic schwannoma were transferred to the phantom. Dose and coordinates of maximum dose point inside the cochlea were derived. The phantom along with the MOSFET dosimeters was irradiated to deliver the planned treatment and dose received by cochlea were measured. The treatment planning system (TPS) estimated and measured dose to the cochlea were in the range of 7.4 - 8.4 Gy and 7.1 - 8 Gy, respectively. The maximum variation between TPS calculated and measured dose to cochlea was 5%. The measured dose values were found in good agreement with the dose values calculated using the TPS. The MOSFET dosimeter can be a suitable choice for routine dose verification in the Gamma Knife radiosurgery.

Stereotactic radiosurgery for the treatment of meningiomas; Radiocirurgia estereotaxica no tratamento de meningiomas

Energy Technology Data Exchange (ETDEWEB)

Penna, Antonio Belmiro Rodrigues Campbell [Hospital dos Servidores do Estado, Rio de Janeiro, RJ (Brazil). Servico de Radioterapia; Marchiori, Edson [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Radiologia; Vieira, Sergio Lannes [Hospital Sao Vicente de Paula, Rio de Janeiro, RJ (Brazil). Servico de Radioterapia; Rossini Junior, Olamir [Clinica Radioterapia Botafogo Ltda., Rio de Janeiro, RJ (Brazil)

2000-04-01

We report the results of the treatment of four patients with inoperable meningiomas who underwent stereotactic radiosurgery using a linear accelerator of 6 MeV. Radiological examinations carried out from 12 to 22 months later revealed tumor growth arrest in all patients, giving a response rate of 100%. No early or late neurological complications dur to the radiosurgical treatment was observed. During the follow-up period no death caused by radiation was reported. Although the number of cases and the follow-up period were insufficient to show statistical significance, the results were satisfactory and thus require further investigations. (author)

Radiosurgery for cerebral arteriovenous malformation during pregnancy: A case report focusing on fetal exposure to radiation

OpenAIRE

Nagayama, Kazuki; Kurita, Hiroki; Tonari, Ayako; Takayama, Makoto; Shiokawa, Yoshiaki

2010-01-01

Introduction: We present the case of a pregnant woman who underwent linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) and we discuss the fetal exposure to radiation. Clinical Presentation: A 20-year-old woman at 18 weeks of gestation presented with right cerebral hemorrhage and underwent urgent evacuation of the hematoma. She recovered well after surgery, but cerebral angiography after the surgery revealed a small deeply seated arteriovenous malformation (AVM) in the right fron...

Role of gamma knife radiosurgery in craniopharyngioma

Directory of Open Access Journals (Sweden)

Ashis Patnaik

2013-01-01

Full Text Available Craniopharyngiomas continue to be a challenge to manage, due to difficulty in complete excision and frequent recurrences. The management protocol remains controversial. They have a tendency to invade the normal brain tissues around them and due to their position in suprasellar region in close relationship with vital structures like optic apparatus, pituitary-hypothalamic axis, complete removal is often not feasible without causing serious morbidity and mortality. In this scenario, sub-total excision seems to be a better alternative, which is plagued by early and frequent recurrences. Radiotherapy has been used for increasing the progression free survival and to improve the overall quality of life. Recently Gamma knife radiosurgery has evolved as a promising technique of radiating the residual or recurrent tumor in a single session with great accuracy and precision. This helps in maximizing the radiation dose to the tumor with steep dose fall off to the surrounding tissue, and hence there is better control of the tumor and minimal radiation exposure to surrounding normal, vital brain tissues. We discuss the current strategies of Gamma knife treatment for craniopharyngioma and review the literature.

SU-E-T-548: How To Decrease Spine Dose In Patients Who Underwent Sterotactic Spine Radiosurgery?

International Nuclear Information System (INIS)

Acar, H; Altinok, A; Kucukmorkoc, E; Kucuk, N; Caglar, H

2014-01-01

Purpose: Stereotactic radiosurgery for spine metastases involves irradiation using a single high dose fraction. The purpose of this study was to dosimetrically compare stereotactic spine radiosurgery(SRS) plans using a recently new volumetric modulated arc therapy(VMAT) technique against fix-field intensity-modulated radiotherapy(IMRT). Plans were evaluated for target conformity and spinal cord sparing. Methods: Fifteen previously treated patients were replanned using the Eclipse 10.1 TPS AAA calculation algorithm. IMRT plans with 7 fields were generated. The arc plans used 2 full arc configurations. Arc and IMRT plans were normalized and prescribed to deliver 16.0 Gy in a single fraction to 90% of the planning target volume(PTV). PTVs consisted of the vertebral body expanded by 3mm, excluding the PRV-cord, where the cord was expanded by 2mm.RTOG 0631 recommendations were applied for treatment planning. Partial spinal cord volume was defined as 5mm above and below the radiosurgery target volume. Plans were compared for conformity and gradient index as well as spinal cord sparing. Results: The conformity index values of fifteen patients for two different treatment planning techniques were shown in table 1. Conformity index values for 2 full arc planning (average CI=0.84) were higher than that of IMRT planning (average CI=0.79). The gradient index values of fifteen patients for two different treatment planning techniques were shown in table 2. Gradient index values for 2 full arc planning (average GI=3.58) were higher than that of IMRT planning (average GI=2.82).The spinal cord doses of fifteen patients for two different treatment planning techniques were shown in table 3. D0.35cc, D0.03cc and partial spinal cord D10% values in 2 full arc plannings (average D0.35cc=819.3cGy, D0.03cc=965.4cGy, 10%partial spinal=718.1cGy) were lower than IMRT plannings (average D0.35cc=877.4cGy, D0.03c=1071.4cGy, 10%partial spinal=805.1cGy). Conclusions: The two arc VMAT technique is

Long-term follow-up reveals low toxicity of radiosurgery for vestibular schwannoma

International Nuclear Information System (INIS)

Rutten, Isabelle; Baumert, Brigitta G.; Seidel, Laurence; Kotolenko, Snezana; Collignon, Jacques; Kaschten, Bruno; Albert, Adelin; Martin, Didier; Deneufbourg, Jean-Marie; Demanez, Jean-Pierre; Stevenaert, Achille

2007-01-01

Aim: The long-term effects of radiosurgery of vestibular schwannomas were investigated in a group of consecutively treated patients. Methods and materials: Between 1995 and 2001, 26 patients (median age: 67, range: 30-82) with a vestibular schwannoma were treated by Linac-based stereotactic radiosurgery (SRS). The median follow-up was 49 months (16-85 months). Only progressive tumours were treated. The median size of tumours was 18 mm (range 9-30 mm). Before SRS, 11 patients had a useful hearing (Gardner-Robertson classes 1 and 2). Single doses of 10-14 Gy were prescribed at the 80% isodose at the tumour margin. The follow-up consisted of regular imaging with MRI the first 3-6 months after the intervention, followed by additional yearly MRIs, a hearing test and a neurological examination. Result: The 5-year-probability of tumour control (defined as stabilization or decrease in size) was 95%. Five-year-probability of preservation of hearing and facial nerve function was 96% and 100%, respectively. Hearing was preserved in 10 out of 11 patients who had a normal or useful hearing at the time of treatment. Mild and transient trigeminal toxicity occurred in 2 (8%) patients. It appeared to be significantly correlated to the dose used (p = 0.044). However, only a tendency to significance could be demonstrated in the relationship between the two factors when using the Cox analysis (hazard ratio = 1.7; 95% CI: 0.7-3.9; p = 0.23). Conclusions: With the doses used, our study demonstrates that SRS provides an equivalent tumour control rate when compared to surgery, as well as on a long-term basis, an excellent preservation of the facial and the acoustic nerves. Although no permanent trigeminal toxicity was observed, our data confirm that doses below 14 Gy can avoid transient dysesthesias

Early changes in volume and non-enhanced volume of acoustic neurinoma after stereotactic gamma-radiosurgery

Energy Technology Data Exchange (ETDEWEB)

Oyama, Hirofumi; Kobayashi, Tatsuya; Kida, Yoshihisa; Tanaka, Takayuki; Mori, Yoshimasa; Iwakoshi, Takayasu; Niwa, Masahiro; Kai, Osamu; Hirose, Mitsuhiko [Komaki City Hospital, Aichi (Japan)

1994-09-01

The effectiveness of stereotactic gamma-radiosurgery for treating acoustic neurinoma was evaluated by measuring the volumes of the tumor, non-enhanced tumor, and cerebellar edema in 13 patients with acoustic neurinoma who were followed up for 9 to 15 months (median 12.7 mos) after treatment. The tumor volume and non-enhanced volume tended to reach a maximum after 6 months, and cerebellar edema volume after 9 months, then decreased gradually thereafter. Hearing loss tended to increase gradually, but involvement of the facial nerve was transient. (author).

Stereotactic radiosurgery vs. fractionated radiotherapy for tumor control in vestibular schwannoma patients

DEFF Research Database (Denmark)

Persson, Oscar; Bartek, Jiri; Shalom, Netanel Ben

2017-01-01

OBJECTIVE: Repeated controlled studies have revealed that stereotactic radiosurgery is better than microsurgery for patients with vestibular schwannoma (VS) ... to patients treated with fractionated stereotactic radiotherapy. RESULTS: No randomized controlled trial (RCT) was identified. None of the identified controlled studies comparing SRS with FSRT were eligible according to the inclusion criteria. Nineteen case series on SRS (n = 17) and FSRT (n = 2) were...... included in the systematic review. Loss of tumor control necessitating a new VS-targeted intervention was found in an average of 5.0% of the patients treated with SRS and in 4.8% treated with FSRT. Mean deterioration ratio for patients with serviceable hearing before treatment was 49% for SRS and 45...

Quality control of radiosurgery: dosimetry with micro camera in spherical mannequin; Control de calidad en radiocirugia: dosimetria con microcamara en maniqui esferico

Energy Technology Data Exchange (ETDEWEB)

Casado Villalon, F. J.; Navarro Guirado, F.; Garci Pareja, S.; Benitez Villegas, E. M.; Galan Montenegro, P.; Moreno Saiz, C.

2013-07-01

The dosimetry of small field is part of quality control in the treatment of cranial radiosurgery. In this work the results of absorbed dose in the isocenter, Planner, with those obtained from are compared experimentally with a micro-camera into an spherical mannequin. (Author)

Gamma Knife Radiosurgery for Choroidal Hemangioma

International Nuclear Information System (INIS)

Kim, Yun Taek; Kang, Se Woong; Lee, Jung-Il

2011-01-01

Purpose: Patients with choroidal hemangioma (CH), a benign ocular hamartoma, frequently presents with visual disturbance as a result of exudative retinal detachment (RD), which originates in subretinal fluid accumulation. We report our experience using the Leksell Gamma Knife in the management of symptomatic CH. Methods and Materials: Seven patients with symptomatic CH (circumscribed form in 3 patients and diffuse form in 4) were treated with the Leksell Gamma Knife at our institution during a 7-year period. All patients presented with exudative RD involving the macula that resulted in severe visual deterioration. The prescription dose to the target margin was 10 Gy in all cases. The mean tumor volume receiving the prescription dose was 536 mm 3 (range, 151–1,057). The clinical data were analyzed in a retrospective fashion after a mean follow-up of 34.4 months (range, 9–76). Results: The resolution of exudative RD was achieved within 6 months, and the visual acuity of the affected eye had improved at the latest follow-up examination (p = .018) in all patients. No recurrence of exudative RD occurred. Thinning of the CHs was observed in most patients; however, symptomatic radiation toxicity had not developed in any of the patients. Conclusion: Symptomatic CHs can be safely and effectively managed with Gamma Knife radiosurgery using a marginal dose of 10 Gy.

Gamma Knife Radiosurgery for Choroidal Hemangioma

Energy Technology Data Exchange (ETDEWEB)

Kim, Yun Taek; Kang, Se Woong [Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Lee, Jung-Il, E-mail: jilee@skku.edu [Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

2011-12-01

Purpose: Patients with choroidal hemangioma (CH), a benign ocular hamartoma, frequently presents with visual disturbance as a result of exudative retinal detachment (RD), which originates in subretinal fluid accumulation. We report our experience using the Leksell Gamma Knife in the management of symptomatic CH. Methods and Materials: Seven patients with symptomatic CH (circumscribed form in 3 patients and diffuse form in 4) were treated with the Leksell Gamma Knife at our institution during a 7-year period. All patients presented with exudative RD involving the macula that resulted in severe visual deterioration. The prescription dose to the target margin was 10 Gy in all cases. The mean tumor volume receiving the prescription dose was 536 mm{sup 3} (range, 151-1,057). The clinical data were analyzed in a retrospective fashion after a mean follow-up of 34.4 months (range, 9-76). Results: The resolution of exudative RD was achieved within 6 months, and the visual acuity of the affected eye had improved at the latest follow-up examination (p = .018) in all patients. No recurrence of exudative RD occurred. Thinning of the CHs was observed in most patients; however, symptomatic radiation toxicity had not developed in any of the patients. Conclusion: Symptomatic CHs can be safely and effectively managed with Gamma Knife radiosurgery using a marginal dose of 10 Gy.

SU-E-T-453: A Novel Daily QA System for Robotic Image Guided Radiosurgery with Variable Aperture Collimator

International Nuclear Information System (INIS)

Wang, L; Nelson, B

2014-01-01

Purpose: A novel end-to-end system using a CCD camera and a scintillator based phantom that is capable of measuring the beam-by-beam delivery accuracy of Robotic Radiosurgery has been developed and reported in our previous work. This work investigates its application to end-to-end type daily QA for Robotic Radiosurgery (Cyberknife) with Variable Aperture Collimator (Iris). Methods: The phantom was first scanned with a CT scanner at 0.625 slice thickness and exported to the Cyberknife Muliplan (v4.6) treatment planning system. An isocentric treatment plan was created consisting of ten beams of 25 Monitor Units each using Iris apertures of 7.5, 10, 15, 20, and 25 mm. The plan was delivered six times in two days on the Cyberknife G4 system with fiducial tracking on the four metal fiducials embedded in phantom with re-positioning between the measurements. The beam vectors (X, Y, Z) are measured and compared with the plan from the machine delivery file (XML file). The Iris apertures (FWHM) were measured from the beam flux map and compared with the commissioning data. Results: The average beam positioning accuracies of the six deliveries are 0.71 ± 0.40 mm, 0.72 ± 0.44 mm, 0.74 ± 0.42 mm, 0.70 ± 0.40 mm, 0.79 ± 0.44 mm and 0.69 ± 0.41 mm respectively. Radiation beam width (FWHM) variations are within ±0.05 mm, and they agree with the commissioning data within 0.22 mm. The delivery time for the plan is about 7 minutes and the results are given instantly. Conclusion: The experimental results agree with stated sub-millimeter delivery accuracy of Cyberknife system. Beam FWHM variations comply with the 0.2 mm accuracy of the Iris collimator at SAD. The XRV-100 system has proven to be a powerful tool in performing end-to-end type tests for Robotic Image Guided Radiosurgery Daily QA

Toxicity of Gamma Knife Radiosurgery in the Treatment of Intracranial Tumors in Patients With Collagen Vascular Diseases or Multiple Sclerosis

Energy Technology Data Exchange (ETDEWEB)

Lowell, Dot [Department of Radiation Oncology, School of Medicine, Wake Forest University, Winston-Salem, NC (United States); Tatter, Stephen B. [Department of Neurosurgery, School of Medicine, Wake Forest University, Winston-Salem, NC (United States); Bourland, J. Daniel; Guzman, Allan F. de; Ekstrand, Kenneth E. [Department of Radiation Oncology, School of Medicine, Wake Forest University, Winston-Salem, NC (United States); Ellis, Thomas L. [Department of Neurosurgery, School of Medicine, Wake Forest University, Winston-Salem, NC (United States); Lovato, James F. [Division of Public Health Sciences, School of Medicine, Wake Forest University, Winston-Salem, NC (United States); McMullen, Kevin P.; Munley, Michael T.; Shaw, Edward G.; Urbanic, James J. [Department of Radiation Oncology, School of Medicine, Wake Forest University, Winston-Salem, NC (United States); Chan, Michael D., E-mail: mchan@wfubmc.edu [Department of Radiation Oncology, School of Medicine, Wake Forest University, Winston-Salem, NC (United States)

2011-11-15

Purpose: To assess toxicity in patients with either a collagen vascular disease (CVD) or multiple sclerosis (MS) treated with intracranial radiosurgery. Methods and Materials: Between January 2004 and April 2009, 6 patients with MS and 14 patients with a CVD were treated with Gamma Knife radiosurgery (GKRS) for intracranial tumors. Treated lesions included 15 total brain metastases in 7 patients, 11 benign brain tumors, 1 low grade glioma, and 1 cavernous malformation. Toxicities were graded by the Radiation Therapy Oncology Group Acute/Late Radiation Morbidity Scoring Criteria. 'Rare toxicities' were characterized as those reported in the scientific literature at an incidence of <5%. Results: Median follow-up time was 16 months. Median dose to the tumor margin was 13.0 Gy (range, 12-21 Gy). Median size of tumor was 5.0 cm{sup 3} (range, 0.14-7.8 cm{sup 3}). Of the 14 patients with CVD, none experienced a Grade 3 or 4 toxicity or a toxicity characterized as rare. Of the 6 patients with MS, 3 experienced rare toxicities, and two of these were Grade 3 toxicities. Rare complications included a patient experiencing both communicating hydrocephalus and facial nerve palsy, as well as 2 additional patients with motor cranial nerve palsy. High-grade toxicities included the patient with an acoustic neuroma requiring ventriculoperitoneal shunt placement for obstructive hydrocephalus, and 1 patient with a facial nerve schwannoma who experienced permanent facial nerve palsy. Interval between radiosurgery and high-grade toxicities ranged from 1 week to 4 months. Conclusions: Our series suggests that patients with MS who receive GKRS may be at increased risk of rare and high-grade treatment-related toxicity. Given the time course of toxicity, treatment-related edema or demyelination represent potential mechanisms.

Gamma Knife Stereotactic Radiosurgery as Salvage Therapy After Failure of Whole-Brain Radiotherapy in Patients With Small-Cell Lung Cancer

International Nuclear Information System (INIS)

Harris, Sunit; Chan, Michael D.; Lovato, James F.; Ellis, Thomas L.; Tatter, Stephen B.; Bourland, J. Daniel; Munley, Michael T.; Guzman, Allan F. de; Shaw, Edward G.; Urbanic, James J.; McMullen, Kevin P.

2012-01-01

Purpose: Radiosurgery has been successfully used in selected cases to avoid repeat whole-brain irradiation (WBI) in patients with multiple brain metastases of most solid tumor histological findings. Few data are available for the use of radiosurgery for small-cell lung cancer (SCLC). Methods and Materials: Between November 1999 and June 2009, 51 patients with SCLC and previous WBI and new brain metastases were treated with GammaKnife stereotactic radiosurgery (GKSRS). A median dose of 18 Gy (range, 10–24 Gy) was prescribed to the margin of each metastasis. Patients were followed with serial imaging. Patient electronic records were reviewed to determine disease-related factors and clinical outcomes after GKSRS. Local and distant brain failure rates, overall survival, and likelihood of neurologic death were determined based on imaging results. The Kaplan-Meier method was used to determine survival and local and distant brain control. Cox proportional hazard regression was performed to determine strength of association between disease-related factors and survival. Results: Median survival time for the entire cohort was 5.9 months. Local control rates at 1 and 2 years were 57% and 34%, respectively. Distant brain failure rates at 1 and 2 years were 58% and 75%, respectively. Fifty-three percent of patients ultimately died of neurologic death. On multivariate analysis, patients with stable (hazard ratio [HR] = 2.89) or progressive (HR = 6.98) extracranial disease (ECD) had worse overall survival than patients without evidence of ECD (p = 0.00002). Concurrent chemotherapy improved local control (HR = 89; p = 0.006). Conclusions: GKSRS represents a feasible salvage option in patients with SCLC and brain metastases for whom previous WBI has failed. The status of patients’ ECD is a dominant factor predictive of overall survival. Local control may be inferior to that seen with other cancer histological results, although the use of concurrent chemotherapy may help to

Gamma Knife Stereotactic Radiosurgery as Salvage Therapy After Failure of Whole-Brain Radiotherapy in Patients With Small-Cell Lung Cancer

Energy Technology Data Exchange (ETDEWEB)

Harris, Sunit [Department of Radiation Oncology, Wake Forest University, Winston-Salem, North Carolina (United States); Chan, Michael D., E-mail: mchan@wfubmc.edu [Department of Radiation Oncology, Wake Forest University, Winston-Salem, North Carolina (United States); Lovato, James F. [Division of Public Health Sciences, Wake Forest University, Winston-Salem, North Carolina (United States); Ellis, Thomas L.; Tatter, Stephen B. [Department of Neurosurgery, Wake Forest University, Winston-Salem, North Carolina (United States); Bourland, J. Daniel; Munley, Michael T.; Guzman, Allan F. de; Shaw, Edward G.; Urbanic, James J.; McMullen, Kevin P. [Department of Radiation Oncology, Wake Forest University, Winston-Salem, North Carolina (United States)

2012-05-01

Purpose: Radiosurgery has been successfully used in selected cases to avoid repeat whole-brain irradiation (WBI) in patients with multiple brain metastases of most solid tumor histological findings. Few data are available for the use of radiosurgery for small-cell lung cancer (SCLC). Methods and Materials: Between November 1999 and June 2009, 51 patients with SCLC and previous WBI and new brain metastases were treated with GammaKnife stereotactic radiosurgery (GKSRS). A median dose of 18 Gy (range, 10-24 Gy) was prescribed to the margin of each metastasis. Patients were followed with serial imaging. Patient electronic records were reviewed to determine disease-related factors and clinical outcomes after GKSRS. Local and distant brain failure rates, overall survival, and likelihood of neurologic death were determined based on imaging results. The Kaplan-Meier method was used to determine survival and local and distant brain control. Cox proportional hazard regression was performed to determine strength of association between disease-related factors and survival. Results: Median survival time for the entire cohort was 5.9 months. Local control rates at 1 and 2 years were 57% and 34%, respectively. Distant brain failure rates at 1 and 2 years were 58% and 75%, respectively. Fifty-three percent of patients ultimately died of neurologic death. On multivariate analysis, patients with stable (hazard ratio [HR] = 2.89) or progressive (HR = 6.98) extracranial disease (ECD) had worse overall survival than patients without evidence of ECD (p = 0.00002). Concurrent chemotherapy improved local control (HR = 89; p = 0.006). Conclusions: GKSRS represents a feasible salvage option in patients with SCLC and brain metastases for whom previous WBI has failed. The status of patients' ECD is a dominant factor predictive of overall survival. Local control may be inferior to that seen with other cancer histological results, although the use of concurrent chemotherapy may help to

Toward acquiring comprehensive radiosurgery field commissioning data using the PRESAGE/optical-CT 3D dosimetry system

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Clift, Corey; Thomas, Andrew; Chang Zheng; Oldham, Mark [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States); Adamovics, John [Department of Chemistry, Rider University, Lawrenceville, NJ 08648 (United States); Das, Indra [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States)], E-mail: cclift@montefiore.org

2010-03-07

Achieving accurate small field dosimetry is challenging. This study investigates the utility of a radiochromic plastic PRESAGE read with optical-CT for the acquisition of radiosurgery field commissioning data from a Novalis Tx system with a high-definition multileaf collimator (HDMLC). Total scatter factors (S{sub c,p}), beam profiles, and penumbrae were measured for five different radiosurgery fields (5, 10, 20, 30 and 40 mm) using a commercially available optical-CT scanner (OCTOPUS, MGS Research). The percent depth dose (PDD), beam profile and penumbra of the 10 mm field were also measured using a higher resolution in-house prototype CCD-based scanner. Gafchromic EBT film was used for independent verification. Measurements of S{sub c,p} made with PRESAGE and film agreed with mini-ion chamber commissioning data to within 4% for every field (range 0.2-3.6% for PRESAGE, and 1.6-3.6% for EBT). PDD, beam profile and penumbra measurements made with the two PRESAGE/optical-CT systems and film showed good agreement with the high-resolution diode commissioning measurements with a competitive resolution (0.5 mm pixels). The in-house prototype optical-CT scanner allowed much finer resolution compared with previous applications of PRESAGE. The advantages of the PRESAGE (registered) system for small field dosimetry include 3D measurements, negligible volume averaging, directional insensitivity, an absence of beam perturbations, energy and dose rate independence.

Toward acquiring comprehensive radiosurgery field commissioning data using the PRESAGE/optical-CT 3D dosimetry system

International Nuclear Information System (INIS)

Clift, Corey; Thomas, Andrew; Chang Zheng; Oldham, Mark; Adamovics, John; Das, Indra

2010-01-01

Achieving accurate small field dosimetry is challenging. This study investigates the utility of a radiochromic plastic PRESAGE read with optical-CT for the acquisition of radiosurgery field commissioning data from a Novalis Tx system with a high-definition multileaf collimator (HDMLC). Total scatter factors (S c,p ), beam profiles, and penumbrae were measured for five different radiosurgery fields (5, 10, 20, 30 and 40 mm) using a commercially available optical-CT scanner (OCTOPUS, MGS Research). The percent depth dose (PDD), beam profile and penumbra of the 10 mm field were also measured using a higher resolution in-house prototype CCD-based scanner. Gafchromic EBT film was used for independent verification. Measurements of S c,p made with PRESAGE and film agreed with mini-ion chamber commissioning data to within 4% for every field (range 0.2-3.6% for PRESAGE, and 1.6-3.6% for EBT). PDD, beam profile and penumbra measurements made with the two PRESAGE/optical-CT systems and film showed good agreement with the high-resolution diode commissioning measurements with a competitive resolution (0.5 mm pixels). The in-house prototype optical-CT scanner allowed much finer resolution compared with previous applications of PRESAGE. The advantages of the PRESAGE (registered) system for small field dosimetry include 3D measurements, negligible volume averaging, directional insensitivity, an absence of beam perturbations, energy and dose rate independence.

Toward acquiring comprehensive radiosurgery field commissioning data using the PRESAGE®/ optical-CT 3D dosimetry system

Science.gov (United States)

Clift, Corey; Thomas, Andrew; Adamovics, John; Chang, Zheng; Das, Indra; Oldham, Mark

2010-03-01

Achieving accurate small field dosimetry is challenging. This study investigates the utility of a radiochromic plastic PRESAGE® read with optical-CT for the acquisition of radiosurgery field commissioning data from a Novalis Tx system with a high-definition multileaf collimator (HDMLC). Total scatter factors (Sc, p), beam profiles, and penumbrae were measured for five different radiosurgery fields (5, 10, 20, 30 and 40 mm) using a commercially available optical-CT scanner (OCTOPUS, MGS Research). The percent depth dose (PDD), beam profile and penumbra of the 10 mm field were also measured using a higher resolution in-house prototype CCD-based scanner. Gafchromic EBT® film was used for independent verification. Measurements of Sc, p made with PRESAGE® and film agreed with mini-ion chamber commissioning data to within 4% for every field (range 0.2-3.6% for PRESAGE®, and 1.6-3.6% for EBT). PDD, beam profile and penumbra measurements made with the two PRESAGE®/optical-CT systems and film showed good agreement with the high-resolution diode commissioning measurements with a competitive resolution (0.5 mm pixels). The in-house prototype optical-CT scanner allowed much finer resolution compared with previous applications of PRESAGE®. The advantages of the PRESAGE® system for small field dosimetry include 3D measurements, negligible volume averaging, directional insensitivity, an absence of beam perturbations, energy and dose rate independence.

Neurosymptomatic carvenous sinus meningioma: a 15-years experience with fractionated stereotactic radiotherapy and radiosurgery

International Nuclear Information System (INIS)

Correa, Sebastião Francisco Miranda; Marta, Gustavo Nader; Teixeira, Manoel Jacobsen

2014-01-01

The tumor removal of Cavernous Sinus Meningiomas usually results in severe neurological deficits. Stereotactic radiosurgery (SRS) and fractionated Stereotactic radiotherapy (SRT) are advanced modalities of radiotherapy for treatment of patients with inoperable and symptomatic CSMs. The authors evaluated the long term symptomatology, the image findings, and the toxicity of patients with CSMs treated with SRS or SRT. From 1994 to 2009, 89 patients with symptomatic CSMs were treated with SRS or SRT. The indication was based on tumour volume and or proximity to the optic chiasm. The median single dose of SRS was 14 Gy, while the SRT total dose, ranged from 50.4 to 54 Gy fractionated in 1.8-2 Gy/dose. The median follow-up period lasted 73 months. The clinical and radiological improvement was the same despite the method of radiotherapy; 41.6% (SRS) and 48.3% (SRT) of patients treated. The disease-free survivals were 98.8%, 92.3% and 92.3%, in 5, 10, and 15 years, respectively. There was no statistical difference in relation to the symptoms and image findings between both methods. According to the Common Toxicity Criteria, 7% of the patients presented transient optic neuropathy during 3 months (grade 2) and recovered with dexamethasone, 2 patients had trigeminal neuropathy (grade 2) and improved rapidly, and one patient presented total occlusion of the internal carotid artery without neurological deficit (grade 2). Temporary lethargy and headache (grade 1) were the most frequent immediate complications. No severe complications occurred. Stereotactic Radiosurgery and fractionated Stereotactic Radiotherapy were equally safe and effective in the management of symptomatic CSMs

Awake craniotomy for excision of arteriovenous malformations? A qualitative comparison study with stereotactic radiosurgery.

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Chan, David Yuen Chung; Chan, Danny Tat Ming; Zhu, Cannon Xian Lun; Kan, Patricia Kwok Yee; Ng, Amelia Yikjin; Hsieh, Yi-Pin Sonia; Abrigo, Jill; Poon, Wai Sang; Wong, George Kwok Chu

2018-05-01

Treatment of arteriovenous malformations (AVM) located at the eloquent area has been a challenge. Awake brain mapping allows identification of a non-eloquent gyrus for intervention and can potentially facilitate resection with preservation of functions. An alternative treatment option is stereotactic radiosurgery (SRS). The objective of this study was to perform a qualitative comparison of the treatment outcome of awake AVM excision versus SRS. We conducted a 13-year retrospective review of AVM excision under awake craniotomy performed at Prince of Wales Hospital, Hong Kong, from 2003 to 2016. Patients' presentation, Spetzler-Martin (SM) grading, rate of obliteration and complication were reviewed and analyzed with the modified radiosurgery-based AVM score (RS score). Six patients had excision of AVM under awake mapping during this period of time. Two were SM Grade II and four were SM Grade III. Five located at the peri-rolandic region while one at the temporal language area. None had failed mapping. Five out of six achieved complete obliteration (83.3%). Qualitative comparative analysis had revealed better treatment outcome with awake AVM excision as compared to SRS with the obliteration rate of 100% versus 96% for RS score ≤1.00, 100% versus 78% for RS score 1.01-1.50, and 66% versus 50% for RS score >2.00 respectively. In conclusion, awake mapping and excision of AVMs at the eloquent area is feasible. Qualitative comparative analysis had revealed higher obliteration rate with awake AVM excision as compared to SRS. Copyright © 2018 Elsevier Ltd. All rights reserved.

Gamma knife radiosurgery for benign cavernous sinus tumors. Treatment concept and outcomes in 120 cases

International Nuclear Information System (INIS)

Hayashi, Motohiro; Chernov, Mikhail; Tamura, Noriko

2012-01-01

Availability of modern computer-aided robotized devices, such as the Automatic Positioning System (APS TM ; Elekta Instruments AB, Stockholm, Sweden) and Perfexion TM (Elekta Instruments AB), allowed us to develop the original concept of robotic gamma knife microradiosurgery, which is based on the very precise irradiation of the lesion with regard to conformity and selectivity; intentional avoidance of the excessive irradiation of functionally-important anatomical structures, particularly cranial nerves, located both within and in the vicinity of the target; and delivery of sufficient irradiation energy to the tumor with the intention to attain lesion shrinkage, while keeping the marginal dose sufficiently low for prevention of possible complications. The results of such treatment strategy were evaluated retrospectively in 120 patients with benign cavernous sinus neoplasms (pituitary adenomas, meningiomas, schwannomas, and hemangiomas), who were followed up from 24 to 78 months (mean 47 months) after radiosurgery. Tumor growth control and shrinkage rates were 98% and 68%, respectively. More than 50% volume reduction was noted in 25% of lesions. The most prominent volumetric tumor response was observed in hemangiomas, followed by schwannomas, pituitary adenomas, and meningiomas. Treatment-related complications were marked in 7% of cases, and were mainly related to transient isolated cranial neuropathy appearing within several months after radiosurgery. Major morbidity was limited to one patient (0.8%). Application of microradiosurgical treatment principles provides effective and safe management of benign cavernous sinus tumors and is associated with high probability of lesion shrinkage and minimal risk of complications. (author)

Technique for Targeting Arteriovenous Malformations Using Frameless Image-Guided Robotic Radiosurgery

International Nuclear Information System (INIS)

Hristov, Dimitre; Liu, Lina; Adler, John R.; Gibbs, Iris C.; Moore, Teri; Sarmiento, Marily; Chang, Steve D.; Dodd, Robert; Marks, Michael; Do, Huy M.

2011-01-01

Purpose: To integrate three-dimensional (3D) digital rotation angiography (DRA) and two-dimensional (2D) digital subtraction angiography (DSA) imaging into a targeting methodology enabling comprehensive image-guided robotic radiosurgery of arteriovenous malformations (AVMs). Methods and Materials: DRA geometric integrity was evaluated by imaging a phantom with embedded markers. Dedicated DSA acquisition modes with preset C-arm positions were configured. The geometric reproducibility of the presets was determined, and its impact on localization accuracy was evaluated. An imaging protocol composed of anterior-posterior and lateral DSA series in combination with a DRA run without couch displacement between acquisitions was introduced. Software was developed for registration of DSA and DRA (2D-3D) images to correct for: (a) small misalignments of the C-arm with respect to the estimated geometry of the set positions and (b) potential patient motion between image series. Within the software, correlated navigation of registered DRA and DSA images was incorporated to localize AVMs within a 3D image coordinate space. Subsequent treatment planning and delivery followed a standard image-guided robotic radiosurgery process. Results: DRA spatial distortions were typically smaller than 0.3 mm throughout a 145-mm x 145-mm x 145-mm volume. With 2D-3D image registration, localization uncertainties resulting from the achievable reproducibility of the C-arm set positions could be reduced to about 0.2 mm. Overall system-related localization uncertainty within the DRA coordinate space was 0.4 mm. Image-guided frameless robotic radiosurgical treatments with this technique were initiated. Conclusions: The integration of DRA and DSA into the process of nidus localization increases the confidence with which radiosurgical ablation of AVMs can be performed when using only an image-guided technique. Such an approach can increase patient comfort, decrease time pressure on clinical and

Development of a head phantom to be used for quality control in stereotactic radiosurgery

International Nuclear Information System (INIS)

Barbosa, Nilseia Aparecida

2010-05-01

It was designed and developed a geometric acrylic head phantom (GHP) for Quality Assurance (QA) in Stereotactic Radiosurgery (SRS). Inside the phantom there are inserts that are able to accommodate acrylic targets representing the tumor tissue and organ at risk in the region cranial brain, the brain stem. The tumor tissue is represented by two semi-spheres of acrylic with a diameter of 13.0 mm and cavities in the central region for accommodation of a TLD-100 detector and a small radiochromic EBT Gafchromic filmstrip. The brain stem is represented by the two parts of acrylic cylinder with a diameter 18.0 mm, 38.0 mm length and cavities along the central region to accommodate the 5 detectors TLD-100 and yet another of EBT film. The distance tumor - brain stem is 2.0 mm. The experimental setup was filled with water, attached to the stereotactic frame to determine the coordinates of the target and underwent computed tomography (CT). Cf images were transferred to the SRS planning system BrainLab (BrainScan). The contours of the lesion and organ at risk were delineated and, through the technique of multiple circular arcs, the planning was conduced with five arches, one isocenter and a collimator of 17.5 mm from the combination between the table and gantry . The dose delivered to the isocenter of the lesion was 3.0 Gy and the total coverage of tumor volume corresponds to the 75% isodose. This experimental arrangement is subjected to radiosurgery treatment, after which the dosimeters are evaluated and their responses compared with the values of planned doses. The linear accelerator used was a Varian CLlNAC 2300 CID, photon beam of 6 MV, installed at the National Cancer Institute (INCA). For verification of dose distributions in 3D, the films were irradiated in three planes: sagittal, caronal and axial. The .films were scanned and digitized on a scanner Microtek ScanMaker 9800XL model. The dose distributions in irradiated films were compared with the distributions of doses

Stereotactic Target point Verification in Actual Treatment Position of Radiosurgery

International Nuclear Information System (INIS)

Yun, Hyong Geun; Lee, Hyun Koo

1995-01-01

Purpose : Authors tried to enhance the safety and accuracy of radiosurgery by verifying stereotactic target point in actual treatment position prior to irradiation. Materials and Methods : Before the actual treatment, several sections of anthropomorphic head phantom were used to create a condition of unknown coordinated of the target point. A film was sand witched between the phantom sections and punctured by sharp needle tip. The tip of the needle represented the target point. The head phantom was fixed to the stereotactic ring and CT scan was done with CT localizer attached to the ring. After the CT scanning, the stereotactic coordinates of the target point were determined. The head phantom was secured to accelerator's treatment couch and the movement of laser isocenter to the stereotactic coordinates determined by CT scanning was performed using target positioner. Accelerator's anteroposterior and lateral portal films were taken using angiographic localizers. The stereotactic coordinates determined by analysis of portal films were compared with the stereotactic coordinates previously determined by CT scanning. Following the correction of discrepancy, the head phantom was irradiated using a stereotactic technique of several arcs. After the irradiation, the film which was sand witched between the phantom sections was developed and the degree of coincidence between the center of the radiation distribution with the target point represented by the hole in the film was measured. In the treatment of actual patients, the way of determining the stereotactic coordinates with CT localizers and angiographic localizers between two sets of coordinates, we proceeded to the irradiation of the actual patient. Results : In the phantom study, the agreement between the center of the radiation distribution and the localized target point was very good. By measuring optical density profiles of the sand witched film along axes that intersected the target point, authors could confirm

Dosimetric measurements of Onyx embolization material for stereotactic radiosurgery

International Nuclear Information System (INIS)

Roberts, Donald A.; Balter, James M.; Chaudhary, Neeraj; Gemmete, Joseph J.; Pandey, Aditya S.

2012-01-01

Purpose: Arteriovenous malformations are often treated with a combination of embolization and stereotactic radiosurgery. Concern has been expressed in the past regarding the dosimetric properties of materials used in embolization and the effects that the introduction of these materials into the brain may have on the quality of the radiosurgery plan. To quantify these effects, the authors have taken large volumes of Onyx 34 and Onyx 18 (ethylene-vinyl alcohol copolymer doped with tantalum) and measured the attenuation and interface effects of these embolization materials. Methods: The manufacturer provided large cured volumes (∼28 cc) of both Onyx materials. These samples were 8.5 cm in diameter with a nominal thickness of 5 mm. The samples were placed on a block tray above a stack of solid water with an Attix chamber at a depth of 5 cm within the stack. The Attix chamber was used to measure the attenuation. These measurements were made for both 6 and 16 MV beams. Placing the sample directly on the solid water stack and varying the thickness of solid water between the sample and the Attix chamber measured the interface effects. The computed tomography (CT) numbers for bulk material were measured in a phantom using a wide bore CT scanner. Results: The transmission through the Onyx materials relative to solid water was approximately 98% and 97% for 16 and 6 MV beams, respectively. The interface effect shows an enhancement of approximately 2% and 1% downstream for 16 and 6 MV beams. CT numbers of approximately 2600–3000 were measured for both materials, which corresponded to an apparent relative electron density (RED) ρ e w to water of approximately 2.7–2.9 if calculated from the commissioning data of the CT scanner. Conclusions: We performed direct measurements of attenuation and interface effects of Onyx 34 and Onyx 18 embolization materials with large samples. The introduction of embolization materials affects the dose distribution of a MV therapeutic beam

Dosimetric comparison of volumetric modulated arc therapy and linear accelerator-based radiosurgery for the treatment of one to four brain metastases.

Science.gov (United States)

Salkeld, Alison L; Unicomb, Kylie; Hayden, Amy J; Van Tilburg, Kevin; Yau, Shan; Tiver, Kenneth

2014-12-01

The purpose of this study is to compare and evaluate volumetric modulated arc therapy (VMAT) and linear accelerator-based radiosurgery (Linac RS) for the treatment of one to four brain metastases. Radiotherapy plans for 10 patients with 1 to 4 brain metastases that were planned and treated using conventional Linac RS were replanned using a mono-isocentric VMAT technique using two to four arcs. The same doses, target volumes and organs at risk (OAR) were used in both plans. The plans were evaluated for target volume coverage, dose conformity, homogeneity and dose to OAR. For VMAT plans, 18/19 brain metastases met acceptable Radiation Therapy Oncology Group (RTOG) radiosurgery dose coverage, homogeneity and conformity criteria. There was no observed difference between the mean homogeneity indices for VMAT and Linac RS plans. VMAT plans had a lower mean RTOG conformity index compared with the Linac RS plans (1.10 ± 0.06 versus 2.06 ± 1.02). For the OAR, there was no difference in maximal doses to the brain stem, optic chiasm or optic nerves. The volume of normal brain receiving 12 Gy was lower in the VMAT plans (13.3 cm(3) versus 23.1 cm(3) ) compared with the Linac RS plans. The mean total number of monitor units (MUs) was 31.3% less in the VMAT plans (5231.2 MU versus 3593.5 MU). Mono-isocentric VMAT plans using two to four arcs meet RTOG radiosurgery quality criteria in patients with one to four brain metastases, with an improvement in conformity and 12-Gy normal brain volume when compared with patients treated with Linac RS at our institution. © 2014 The Royal Australian and New Zealand College of Radiologists.

Clinical Evaluation of Stereotactic Target Localization Using 3-Tesla MRI for Radiosurgery Planning

International Nuclear Information System (INIS)

MacFadden, Derek; Zhang Beibei; Brock, Kristy K.; Hodaie, Mojgan; Laperriere, Normand; Schwartz, Michael; Tsao, May; Stainsby, Jeffrey; Lockwood, Gina; Mikulis, David; Menard, Cynthia

2010-01-01

Purpose: Increasing the magnetic resonance imaging (MRI) field strength can improve image resolution and quality, but concerns remain regarding the influence on geometric fidelity. The objectives of the present study were to spatially investigate the effect of 3-Tesla (3T) MRI on clinical target localization for stereotactic radiosurgery. Methods and Materials: A total of 39 patients were enrolled in a research ethics board-approved prospective clinical trial. Imaging (1.5T and 3T MRI and computed tomography) was performed after stereotactic frame placement. Stereotactic target localization at 1.5T vs. 3T was retrospectively analyzed in a representative cohort of patients with tumor (n = 4) and functional (n = 5) radiosurgical targets. The spatial congruency of the tumor gross target volumes was determined by the mean discrepancy between the average gross target volume surfaces at 1.5T and 3T. Reproducibility was assessed by the displacement from an averaged surface and volume congruency. Spatial congruency and the reproducibility of functional radiosurgical targets was determined by comparing the mean and standard deviation of the isocenter coordinates. Results: Overall, the mean absolute discrepancy across all patients was 0.67 mm (95% confidence interval, 0.51-0.83), significantly .4), and the gross target volume surface mean displacements were similar within and between users. The overall average isocenter coordinate discrepancy for the functional targets at 1.5T and 3T was 0.33 mm (95% confidence interval, 0.20-0.48), with no patient-specific differences between the mean values (p >.2) or standard deviations (p >.1). Conclusion: Our results have provided clinically relevant evidence supporting the spatial validity of 3T MRI for use in stereotactic radiosurgery under the imaging conditions used.

Gammaknife radiosurgery in patients with acromegaly.

Science.gov (United States)

Erdur, Fatih M; Kilic, Türker; Peker, Selcuk; Celik, Ozlem; Kadioglu, Pinar

2011-12-01

We aimed to evaluate the efficacy and reliability of gamma-knife radiosurgery (GKR) in 22 patients with acromegaly at the Endocrinology-Metabolism Clinic of Cerrahpasa Medical School. We collected data retrospectively from hospital records on disease activity and other pituitary functions, pituitary MRI and visual fields, before GKR and 6, 12, 24, 36, 48 and 60 months after GKR. The median follow-up duration after GKR was 60 months (interquartile range [IQR]: 24-60 months). The remission rate was 54.5% after the 60 months of follow-up. The median growth hormone (GH) level at 60 months after GKR (0.99 ng/mL [IQR: 0.36-2.2]) was significantly lower than the median GH level before GKR (5.65 ng/mL [IQR: 3.85-7.2] (p=0.002). The median insulin-like growth factor-1 (IGF-1) level 60 months after GKR (221.5 ng/mL [IQR: 149-535]) was significantly lower than the median IGF-1 level before GKR (582.5 ng/mL [IQR: 515-655]) (p=0.008). Tumour growth was well controlled in 20 patients (95.2%). Six patients (28.6%) developed new-onset hypopituitarism. We concluded that GKR is an effective adjuvant treatment to control tumour growth, lower GH and IGF-1 levels, and to increase remission rates in patients with acromegaly who were refractory to surgical and medical treatment. Copyright © 2011 Elsevier Ltd. All rights reserved.

Gamma knife radiosurgery under general anesthesia in childhood

International Nuclear Information System (INIS)

Higuchi, Yoshinori; Serizawa, Toru; Nagano, Osamu

2008-01-01

Gamma knife radiosurgery (GKS) is an important treatment option for pediatric intracranial diseases, such as arteriovenous malformations and brain tumors. To perform GKS in children, general anesthesia is required for placing a stereotactic frame around the head of the patient, who must remain supine for the entire procedure. This report describes the anesthetic management of children who have undergone GKS at our institution. Fifty-one GKS procedures were performed in 43 patients (age range, 2-15 years). Twenty-one patients had arteriovenous malformations, and 14 patients had brain tumors. Twenty-nine patients (67.4%) received general anesthesia. All children 10 years or younger were treated under general anesthesia. General anesthesia for GKS is performed outside of the operating room and involves unique conditions. First, the patients must be transported to multiple sites in the hospital (the neuroangiography suite, the department of radiology for magnetic resonance imaging and computed tomography, and the gamma knife unit). Second, general anesthesia must be maintained in a high magnetic field. Third, medical staff, including anesthesiologists, must remain outside the room during irradiation. Safe and efficient general anesthesia is essential for performing GKS in children. (author)

Vestibular schwannomas: clinical results and quality of life after microsurgery or gamma knife radiosurgery.

Science.gov (United States)

Myrseth, Erling; Møller, Per; Pedersen, Paal-Henning; Vassbotn, Flemming S; Wentzel-Larsen, Tore; Lund-Johansen, Morten

2005-05-01

The aim of the present study was to evaluate the overall treatment efficacy (tumor control, facial nerve function, complications) and quality of life for patients treated primarily for unilateral vestibular schwannomas of 30 mm or less, either by microsurgery or by gamma knife (GK) radiosurgery. The results for the two treatment groups are compared with each other, with main emphasis on the long-term quality of life. This is a retrospective study of 189 consecutive patients, 86 treated by microsurgery and 103 by gamma knife. The mean observation time was 5.9 years. All patients had a magnetic resonance imaging scan and clinical evaluation performed toward the end of the study. To evaluate the quality of life, we used two standardized questionnaires, the Glasgow Benefit Inventory and Short-Form 36. The questionnaires were sent to the 168 living patients. The reply rate was 83.3%. A total of 79.8% of the patients in the microsurgery group and 94.8% of the GK patients had a good facial nerve function (House-Brackmann Grade 1-2). Hearing was usually lost after microsurgery, whereas the GK patients had preserved hearing, which often became reduced over the years after the treatment. The treatment efficacy, defined as no need for additional treatment, was similar for the two treatment modalities. Quality of life was reduced compared with normative data, being most reduced in the microsurgery group. Some of the quality of life questions showed an association with facial nerve function and sex. Posttreatment facial nerve function, hearing, complication rates, and quality of life were all significantly in favor of GK radiosurgery.

Feasibility of Single-Isocenter Volumetric Modulated Arc Radiosurgery for Treatment of Multiple Brain Metastases

International Nuclear Information System (INIS)

Clark, Grant M.; Popple, Richard A.; Young, P. Edward; Fiveash, John B.

2010-01-01

Purpose: To evaluate the relative plan quality of single-isocenter vs. multi-isocenter volumetric modulated arc therapy (VMAT) for radiosurgical treatment of multiple central nervous system metastases. Methods and Materials: VMAT plans were created using RapidArc technology for treatment of simulated patients with three brain metastases. The plans consisted of single-arc/single-isocenter, triple-arc (noncoplanar)/single-isocenter, and triple-arc (coplanar)/triple-isocenter configurations. All VMAT plans were normalized to deliver 100% of the 20-Gy prescription dose to all lesions. The plans were evaluated by calculation of Paddick and Radiation Therapy Oncology Group conformity index scores, Paddick gradient index scores, and 12-Gy isodose volumes. Results: All plans were judged clinically acceptable, but differences were observed in the dosimetric parameters, with the use of multiple noncoplanar arcs showing small improvements in the conformity indexes compared with the single-arc/single-isocenter and triple-arc (coplanar)/triple-isocenter plans. Multiple arc plans (triple-arc [noncoplanar]/single-isocenter and triple-arc [coplanar]/triple-isocenter) showed smaller 12-Gy isodose volumes in scenarios involving three metastases spaced closely together, with only small differences noted among all plans involving lesions spaced further apart. Conclusion: Our initial results suggest that single-isocenter VMAT plans can be used to deliver conformity equivalent to that of multiple isocenter VMAT techniques. For targets that are closely spaced, multiple noncoplanar single-isocenter arcs might be required. VMAT radiosurgery for multiple targets using a single isocenter can be efficiently delivered, requiring less than one-half the beam time required for multiple isocenter set ups. VMAT radiosurgery will likely replace multi-isocenter techniques for linear accelerator-based treatment of multiple targets.

Pseudocapsule formation after gamma knife radiosurgery for trigeminal neurinoma. Case report

International Nuclear Information System (INIS)

Akiyama, Takenori; Ikeda, Eiji; Kawase, Takeshi; Yoshida, Kazunari

2005-01-01

A 38-year-old female presented with a trigeminal neurinoma manifesting as left facial paresthesia. The diagnosis was based on magnetic resonance (MR) imaging findings. Gamma knife radiosurgery (GKR) was performed at another hospital at her request. Fifteen months after the GKR, follow-up MR imaging revealed tumor regrowth causing extensive compression of the brainstem, and cyst formation in the tumor. Her clinical symptoms including facial pain and diplopia had worsened, so she was referred to our affiliated hospital for microsurgery. The tumor was totally resected, but the left trigeminal nerve had to be sacrificed because of pseudocapsule formation which covered both the tumor and the trigeminal nerve fibers. The diplopia disappeared, but her facial pain deteriorated after the operation. GKR can induce fibrosis or degenerative change in nearby structures, which may complicate subsequent surgery. (author)

The evolving role of radiosurgery in the management of radiation-induced meningiomas: a review of current advances and future directions.

Science.gov (United States)

Mansouri, Alireza; Badhiwala, Jetan; Mansouri, Sheila; Zadeh, Gelareh

2014-01-01

Meningiomas are among the most common primary adult brain tumors, which arise either spontaneously or secondary to environmental factors such as ionizing radiation. The latter are referred to as radiation-induced meningiomas (RIMs) which, while much less common than their spontaneous counterparts, are challenging from a management point of view. Similar to spontaneous meningiomas, the optimal management of RIMs is complete surgical resection. However, given their high grade, multiplicity, tendency to invade bone and venous sinuses, and high recurrence rate, this cannot always be accomplished safely. Therefore, other therapeutic modalities, such as stereotactic radiosurgery, have emerged. In the current review, we provide an overview of the historical outcomes achieved for RIMs through radiosurgery and microsurgical resection. Furthermore, we provide a discussion of clinical and radiological parameters that affect the decision-making process with regard to the management of RIMs. We also provide an outline of recent changes in our understanding of RIMs, based on molecular and genetic markers, and how these will change our management perspective. We conclude the review by summarizing some of the current obstacles in the management of RIMs with SRS and how current and future research can address these challenges.

The Evolving Role of Radiosurgery in the Management of Radiation-Induced Meningiomas: A Review of Current Advances and Future Directions

Directory of Open Access Journals (Sweden)

Alireza Mansouri

2014-01-01

Full Text Available Meningiomas are among the most common primary adult brain tumors, which arise either spontaneously or secondary to environmental factors such as ionizing radiation. The latter are referred to as radiation-induced meningiomas (RIMs which, while much less common than their spontaneous counterparts, are challenging from a management point of view. Similar to spontaneous meningiomas, the optimal management of RIMs is complete surgical resection. However, given their high grade, multiplicity, tendency to invade bone and venous sinuses, and high recurrence rate, this cannot always be accomplished safely. Therefore, other therapeutic modalities, such as stereotactic radiosurgery, have emerged. In the current review, we provide an overview of the historical outcomes achieved for RIMs through radiosurgery and microsurgical resection. Furthermore, we provide a discussion of clinical and radiological parameters that affect the decision-making process with regard to the management of RIMs. We also provide an outline of recent changes in our understanding of RIMs, based on molecular and genetic markers, and how these will change our management perspective. We conclude the review by summarizing some of the current obstacles in the management of RIMs with SRS and how current and future research can address these challenges.

A Monte Carlo multiple source model applied to radiosurgery narrow photon beams

International Nuclear Information System (INIS)

Chaves, A.; Lopes, M.C.; Alves, C.C.; Oliveira, C.; Peralta, L.; Rodrigues, P.; Trindade, A.

2004-01-01

Monte Carlo (MC) methods are nowadays often used in the field of radiotherapy. Through successive steps, radiation fields are simulated, producing source Phase Space Data (PSD) that enable a dose calculation with good accuracy. Narrow photon beams used in radiosurgery can also be simulated by MC codes. However, the poor efficiency in simulating these narrow photon beams produces PSD whose quality prevents calculating dose with the required accuracy. To overcome this difficulty, a multiple source model was developed that enhances the quality of the reconstructed PSD, reducing also the time and storage capacities. This multiple source model was based on the full MC simulation, performed with the MC code MCNP4C, of the Siemens Mevatron KD2 (6 MV mode) linear accelerator head and additional collimators. The full simulation allowed the characterization of the particles coming from the accelerator head and from the additional collimators that shape the narrow photon beams used in radiosurgery treatments. Eight relevant photon virtual sources were identified from the full characterization analysis. Spatial and energy distributions were stored in histograms for the virtual sources representing the accelerator head components and the additional collimators. The photon directions were calculated for virtual sources representing the accelerator head components whereas, for the virtual sources representing the additional collimators, they were recorded into histograms. All these histograms were included in the MC code, DPM code and using a sampling procedure that reconstructed the PSDs, dose distributions were calculated in a water phantom divided in 20000 voxels of 1x1x5 mm 3 . The model accurately calculates dose distributions in the water phantom for all the additional collimators; for depth dose curves, associated errors at 2σ were lower than 2.5% until a depth of 202.5 mm for all the additional collimators and for profiles at various depths, deviations between measured

Failure mode and effects analysis and fault tree analysis of surface image guided cranial radiosurgery.

Science.gov (United States)

Manger, Ryan P; Paxton, Adam B; Pawlicki, Todd; Kim, Gwe-Ya

2015-05-01

Surface image guided, Linac-based radiosurgery (SIG-RS) is a modern approach for delivering radiosurgery that utilizes optical stereoscopic imaging to monitor the surface of the patient during treatment in lieu of using a head frame for patient immobilization. Considering the novelty of the SIG-RS approach and the severity of errors associated with delivery of large doses per fraction, a risk assessment should be conducted to identify potential hazards, determine their causes, and formulate mitigation strategies. The purpose of this work is to investigate SIG-RS using the combined application of failure modes and effects analysis (FMEA) and fault tree analysis (FTA), report on the effort required to complete the analysis, and evaluate the use of FTA in conjunction with FMEA. A multidisciplinary team was assembled to conduct the FMEA on the SIG-RS process. A process map detailing the steps of the SIG-RS was created to guide the FMEA. Failure modes were determined for each step in the SIG-RS process, and risk priority numbers (RPNs) were estimated for each failure mode to facilitate risk stratification. The failure modes were ranked by RPN, and FTA was used to determine the root factors contributing to the riskiest failure modes. Using the FTA, mitigation strategies were formulated to address the root factors and reduce the risk of the process. The RPNs were re-estimated based on the mitigation strategies to determine the margin of risk reduction. The FMEA and FTAs for the top two failure modes required an effort of 36 person-hours (30 person-hours for the FMEA and 6 person-hours for two FTAs). The SIG-RS process consisted of 13 major subprocesses and 91 steps, which amounted to 167 failure modes. Of the 91 steps, 16 were directly related to surface imaging. Twenty-five failure modes resulted in a RPN of 100 or greater. Only one of these top 25 failure modes was specific to surface imaging. The riskiest surface imaging failure mode had an overall RPN-rank of eighth

Development and validation of a CT-3D rotational angiography registration method for AVM radiosurgery

International Nuclear Information System (INIS)

Stancanello, Joseph; Cavedon, Carlo; Francescon, Paolo; Cerveri, Pietro; Ferrigno, Giancarlo; Colombo, Federico; Perini, Stefano

2004-01-01

In this paper a novel technique is proposed and validated for radiosurgery treatment planning of arteriovenous malformations (AVMs). The technique was developed for frameless radiosurgery by means of the CyberKnife, a nonisocentric, linac-based system which allows highly conformed isodose surfaces to be obtained, while also being valid for other treatment strategies. The technique is based on registration between computed tomography (CT) and three-dimensional rotational angiography (3DRA). Tests were initially performed on the effectiveness of the correction method for distortion offered by the angiographic system. These results determined the registration technique that was ultimately chosen. For CT-3DRA registration, a twelve-parameter affine transformation was selected, based on a mutual information maximization algorithm. The robustness of the algorithm was tested by attempting to register data sets increasingly distant from each other, both in translation and rotation. Registration accuracy was estimated by means of the 'full circle consistency test'. A registration quality index (expressed in millimeters) based on these results was also defined. A hybrid subtraction between CT and 3DRA is proposed in order to improve 3D reconstruction. Preprocessing improved the ability of the algorithm to find an acceptable solution to the registration process. The robustness tests showed that data sets must be manually prealigned within approximately 15 mm and 20 deg. with respect to all three directions simultaneously. Results of the consistency test showed agreement between the quality index and registration accuracy stated by visual inspection in 20 good and 10 artificially worsened registration processes. The quality index showed values smaller than the maximum voxel size (mean 0.8 mm compared to 2 mm) for all successful registrations, while it resulted in much greater values (mean 20 mm) for unsuccessful registrations. Once registered, the two data sets can be used for

Gamma Knife radiosurgery for intracranial meningiomas: Do we need to treat the dural tail? A single-center retrospective analysis and an overview of the literature.

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Bulthuis, Vincent J; Hanssens, Patrick E J; Lie, Suan Te; van Overbeeke, Jacobus J

2014-01-01

The dural tail (DT) has been described as a common feature in meningiomas. There is a great variation of tumor invasion and extent of tumor cells in the DT. Therefore, the necessity to include the whole DT in Gamma Knife radiosurgery is not clear, since inclusion increases the target volume and therefore increases the risk of complications. In this analysis, we evaluated whether the complete tail should be included as part of the target in Gamma Knife radiosurgery for meningiomas. Between June 2002 and December 2010, Gamma Knife radiosurgery was performed in 160 patients with 203 meningiomas with a DT. In 105 tumors, the diagnosis was based on magnetic resonance imaging (MRI) characteristics, and in 98 tumors, the diagnosis was confirmed by histopathologic examination after surgery. The median volume of the tumors was 3.55 cc. All tumors were treated with Gamma Knife radiosurgery with a median prescribed dose of 13 Gy (range 11-15), resulting in a median marginal dose of 11 Gy (range 10-15). Only the part of the DT closely related to the tumor mass was included in the target. The median follow-up period was 41 months (range 12-123). In image-based meningiomas, the overall local control rate was 96.2% with 2- and 5-year control rates of 98.0% and 95.1%, respectively. In WHO grade I tumors, the overall local control rate was 85.9% with 2- and 5-year control rates of 94.5% and 88.0%, respectively. The overall local control rate in World Health Organization (WHO) grade II tumors was 70.6% with control rates of 83.4% and 64.4% after 2 and 5 years, respectively. The growth of all new tumors was found in the radiation target area. No tumor growth was observed in the part of the DT that had been excluded from the target volume. We found in this study that routinely excluding the DT from the target does not lead to out-of-field tumor progression. Given the possibility that the DT is infiltrated with tumor cells, regular follow-up is needed.

Stereotactic radiosurgery for newly diagnosed brain metastases. Comparison of three dose levels

International Nuclear Information System (INIS)

Rades, Dirk; Hornung, Dagmar; Blanck, Oliver; Martens, Kristina; Khoa, Mai Trong; Trang, Ngo Thuy; Hueppe, Michael; Terheyden, Patrick; Gliemroth, Jan; Schild, Steven E.

2014-01-01

Three doses were compared for local control of irradiated metastases, freedom from new brain metastases, and survival in patients receiving stereotactic radiosurgery (SRS) alone for one to three newly diagnosed brain metastases. In all, 134 patients were assigned to three groups according to the SRS dose given to the margins of the lesions: 13-16 Gy (n = 33), 18 Gy (n = 18), and 20 Gy (n = 83). Additional potential prognostic factors were evaluated: age (≤ 60 vs. > 60 years), gender, Karnofsky Performance Scale score (70-80 vs. 90-100), tumor type (non-small-cell lung cancer vs. melanoma vs. others), number of brain metastases (1 vs. 2-3), lesion size ( 24 months). For 13-16 Gy, 18 Gy, and 20 Gy, the 1-year local control rates were 31, 65, and 79 %, respectively (p [de

Small Radiation Beam Dosimetry for Radiosurgery of Trigeminal Neuralgia: One Case Analysis

International Nuclear Information System (INIS)

Garcia-Garduno, O. A.; Larraga-Gutierrez, J. M.; Rodriguez-Villafuerte, M.; Martinez-Davalos, A.; Moreno-Jimenez, S.; Suarez-Campos, J. J.; Celis, M. A.

2008-01-01

The use of small radiation beams for trigeminal neuralgia (TN) treatment requires high precision and accuracy in dose distribution calculations and delivery. Special attention must be kept on the type of detector to be used. In this work, the use of GafChromic EBT registered radiochromic and X-OMAT V2 radiographic films for small radiation beam characterization is reported. The dosimetric information provided by the films (total output factors, tissue maximum ratios and off axis ratios) is compared against measurements with a shielded solid state (diode) reference detector. The film dosimetry was used for dose distribution calculations for the treatment of trigeminal neuralgia radiosurgery. Comparison of the isodose curves shows that the dosimetry produced with the X-OMAT radiographic film overestimates the dose distributions in the penumbra region

Clinical efficacy and safety of surface imaging guided radiosurgery (SIG-RS) in the treatment of benign skull base tumors.

Science.gov (United States)

Lau, Steven K M; Patel, Kunal; Kim, Teddy; Knipprath, Erik; Kim, Gwe-Ya; Cerviño, Laura I; Lawson, Joshua D; Murphy, Kevin T; Sanghvi, Parag; Carter, Bob S; Chen, Clark C

2017-04-01

Frameless, surface imaging guided radiosurgery (SIG-RS) is a novel platform for stereotactic radiosurgery (SRS) wherein patient positioning is monitored in real-time through infra-red camera tracking of facial topography. Here we describe our initial clinical experience with SIG-RS for the treatment of benign neoplasms of the skull base. We identified 48 patients with benign skull base tumors consecutively treated with SIG-RS at a single institution between 2009 and 2011. Patients were diagnosed with meningioma (n = 22), vestibular schwannoma (n = 20), or nonfunctional pituitary adenoma (n = 6). Local control and treatment-related toxicity were retrospectively assessed. Median follow-up was 65 months (range 61-72 months). Prescription doses were 12-13 Gy in a single fraction (n = 18), 8 Gy × 3 fractions (n = 6), and 5 Gy × 5 fractions (n = 24). Actuarial tumor control rate at 5 years was 98%. No grade ≥3 treatment-related toxicity was observed. Grade ≤2 toxicity was associated with symptomatic lesions (p = 0.049) and single fraction treatment (p = 0.005). SIG-RS for benign skull base tumors produces clinical outcomes comparable to conventional frame-based SRS techniques while enhancing patient comfort.

Results of Gamma Knife Radiosurgery in Acromegaly

Directory of Open Access Journals (Sweden)

Alberto Franzin

2012-01-01

Full Text Available Objective. Single-session radiosurgery with Gamma Knife (GK may be a potential adjuvant treatment in acromegaly. We analyzed the safety and efficacy of GK in patients who had previously received maximal surgical debulking at our hospital. Methods. The study was a retrospective analysis of hormonal, radiological, and ophthalmologic data collected in a predefined protocol from 1994 to 2009. The mean age at treatment was 42.3 years (range 22–67 yy. 103 acromegalic patients participated in the study. The median follow-up was 71 months (IQ range 43–107. All patients were treated with GK for residual or recurrent GH-secreting adenoma. Results. Sixty-three patients (61.2% reached the main outcome of the study. The rate of remission was 58.3% at 5 years (95% CI 47.6–69.0%. Other 15 patients (14.6% were in remission after GK while on treatment with somatostatin analogues. No serious side effects occurred after GK. Eight patients (7.8% experienced a new deficit of pituitary function. New cases of hypogonadism, hypothyroidism, and hypoadrenalism occurred in 4 of 77 patients (5.2%, 3 of 95 patients (3.2%, and 6 of 100 patients at risk (6.0%, respectively. Conclusion. In a highly selected group of acromegalic patients, GK treatment had good efficacy and safety.

The use of a Leksell-BRW adapter for linac radiosurgery as an adjunct to Gamma Knife treatment

International Nuclear Information System (INIS)

Ekstrand, Kenneth E; Hinson, William H; Bourland, J Daniel; Guzman, Allan F de; Stieber, Volker W; Tatter, Steven B; Ellis, Thomas L

2003-01-01

We have investigated the use of an adapter that permits the use of a Leksell coordinate frame with a linear accelerator stereotactic radiosurgery system based on the Brown-Robert-Wells (BRW) design. This device is useful when lesions that are planned for treatment on a Leksell Gamma Knife system are found to be inaccessible to the Gamma Knife. We have found that with this device objects within a head phantom can be targeted by the linear accelerator within an accuracy of approximately 1 mm

The use of a Leksell-BRW adapter for linac radiosurgery as an adjunct to Gamma Knife treatment

Energy Technology Data Exchange (ETDEWEB)

Ekstrand, Kenneth E [Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Hinson, William H [Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Bourland, J Daniel [Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Guzman, Allan F de [Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Stieber, Volker W [Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Tatter, Steven B [Department of Neurosurgery, Wake Forest University School of Medicine, Winston-Salem, NC (United States); Ellis, Thomas L [Department of Neurosurgery, Wake Forest University School of Medicine, Winston-Salem, NC (United States)

2003-12-21

We have investigated the use of an adapter that permits the use of a Leksell coordinate frame with a linear accelerator stereotactic radiosurgery system based on the Brown-Robert-Wells (BRW) design. This device is useful when lesions that are planned for treatment on a Leksell Gamma Knife system are found to be inaccessible to the Gamma Knife. We have found that with this device objects within a head phantom can be targeted by the linear accelerator within an accuracy of approximately 1 mm.

New Techniques for Optimal Treatment Planning for LINAC-based Sterotactic Radiosurgery

International Nuclear Information System (INIS)

Suh, Tae Suk

1992-01-01

Since LINAC-based stereotactic radiosurgery uses multiple noncoplanar arcs, three-dimensional dose evaluation and many beam parameters, a lengthy computation time is required to optimize even the simplest case by a trial and error. The basic approach presented in this paper is to show promising methods using an experimental optimization and an analytic optimization. The purpose of this paper is not to describe the detailed methods, but introduce briefly, proceeding research done currently or in near future. A more detailed description will be shown in ongoing published papers. Experimental optimization is based on two approaches. One is shaping the target volumes through the use of multiple isocenters determined from dose experience and testing. The other method is conformal therapy using a beam eye view technique and field shaping. The analytic approach is to adapt computer-aided design optimization in finding optimum irradiation parameters automatically

Gamma knife radiosurgery for glomus jugulare tumors: therapeutic advantages of minimalism in the skull base.

Science.gov (United States)

Sharma, Manish S; Gupta, A; Kale, S S; Agrawal, D; Mahapatra, A K; Sharma, B S

2008-01-01

Glomus jugulare (GJ) tumors are paragangliomas found in the region of the jugular foramen. Surgery with/without embolization and conventional radiotherapy has been the traditional management option. To analyze the efficacy of gamma knife radiosurgery (GKS) as a primary or an adjunctive form of therapy. A retrospective analysis of patients who received GKS at a tertiary neurosurgical center was performed. Of the 1601 patients who underwent GKS from 1997 to 2006, 24 patients with GJ underwent 25 procedures. The average age of the cohort was 46.6 years (range, 22-76 years) and the male to female ratio was 1:2. The most common neurological deficit was IX, X, XI cranial nerve paresis (15/24). Fifteen patients received primary GKS. Mean tumor size was 8.7 cc (range 1.1-17.2 cc). The coverage achieved was 93.1% (range 90-97%) using a mean tumor margin dose of 16.4 Gy (range 12-25 Gy) at a mean isodose of 49.5% (range 45-50%). Thirteen patients (six primary and seven secondary) were available for follow-up at a median interval of 24 months (range seven to 48 months). The average tumor size was 7.9 cc (range 1.1-17.2 cc). Using a mean tumor margin dose of 16.3 Gy (range 12-20 Gy) 93.6% coverage (range 91-97%) was achieved. Six patients improved clinically. A single patient developed transient trigeminal neuralgia. Magnetic resonance imaging follow-up was available for 10 patients; seven recorded a decrease in size. There was no tumor progression. Gamma knife radiosurgery is a safe and effective primary and secondary modality of treatment for GJ.

Clinical experience with image-guided robotic radiosurgery (the Cyberknife) in the treatment of brain and spinal cord tumors

International Nuclear Information System (INIS)

Chang, S.D.; Murphy, M.; Geis, P.; Martin, D.P.; Hancock, S.L.; Doty, J.R.; Adler, J.R. Jr.

1998-01-01

The Cyberknife is an image-guided ''frameless'' dedicated radiosurgical device. This instrument has several distinct advantages over frame-based systems, including improved patient comfort, increased treatment degrees of freedom, and the potential to target extracranial lesions. Clinical results thus far with respect to the treatment of malignant intracranial tumors has been promising. Additionally, the Cyberknife will likely revolutionize the application of radiosurgery to extracranial sites. A description of the components, treatment planning, and clinical results of the Cyberknife will be reviewed. (author)

Results of a Conservative Dose Plan Linear Accelerator-Based Stereotactic Radiosurgery for Pediatric Intracranial Arteriovenous Malformations.

Science.gov (United States)

Rajshekhar, Vedantam; Moorthy, Ranjith K; Jeyaseelan, Visalakshi; John, Subhashini; Rangad, Faith; Viswanathan, P N; Ravindran, Paul; Singh, Rabiraja

2016-11-01

To evaluate the obliteration rate and clinical outcome following linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) for intracranial arteriovenous malformation (AVM) in pediatric patients (age ≤18 years). Factors associated with the obliteration rate and neurologic complications were studied retrospectively in pediatric patients who underwent LINAC-based SRS for AVM between June 1995 and May 2014. The study cohort comprised 36 males and 33 females, with a median age at the time of SRS of 14 years (range, 7-18 years). The mean AVM volume was 8.5 ± 8.7 cc (range, 0.6-41.8 cc). The median marginal dose of radiation delivered was 15 Gy (range, 9-20 Gy). Magnetic resonance imaging (MRI) demonstrated complete obliteration of the AVM in 44 of the 69 patients (63.8%), at a mean follow up of 27.5 months (range, 12-90 months). On subgroup analysis, 41 of the 53 AVMs of ≤14 cc in volume (77.3%) were obliterated. AVMs with a modified AVM radiosurgery score <1 had significantly shorter obliteration times from the time of SRS (P = .006). On multivariate analysis, the mean marginal dose of radiation delivered to the AVM was the sole significant predictor of obliteration (odds ratio, 1.6; 95% confidence interval, 1 to 2.4). A modest median marginal dose of 15 Gy (16 Gy in the obliterated AVM group vs. 12 Gy in the nonobliterated group) resulted in an obliteration rate of 66.7% after LINAC-based SRS for intracranial AVM, with low rate. Copyright © 2016 Elsevier Inc. All rights reserved.

A randomised trial to compare cognitive outcome after gamma knife radiosurgery versus whole brain radiation therapy in patients with multiple brain metastases : Research protocol CAR-study B

NARCIS (Netherlands)

Schimmel, W.C.M.; Verhaak, E.; Hanssens, Patrick E. J.; Gehring, K.; Sitskoorn, M.M.

2018-01-01

Background Gamma Knife radiosurgery (GKRS) is increasingly applied in patients with multiple brain metastases and is expected to have less adverse effects in cognitive functioning than whole brain radiation therapy (WBRT). Effective treatment with the least negative cognitive side effects is

Long-term Evaluation of Radiation-Induced Optic Neuropathy After Single-Fraction Stereotactic Radiosurgery

International Nuclear Information System (INIS)

Leavitt, Jacqueline A.; Stafford, Scott L.; Link, Michael J.; Pollock, Bruce E.

2013-01-01

Purpose: To determine the long-term risk of radiation-induced optic neuropathy (RION) in patients having single-fraction stereotactic radiosurgery (SRS) for benign skull base tumors. Methods and Materials: Retrospective review of 222 patients having Gamma Knife radiosurgery for benign tumors adjacent to the anterior visual pathway (AVP) between 1991 and 1999. Excluded were patients with prior or concurrent external beam radiation therapy or SRS. One hundred twenty-nine patients (58%) had undergone previous surgery. Tumor types included confirmed World Health Organization grade 1 or presumed cavernous sinus meningioma (n=143), pituitary adenoma (n=72), and craniopharyngioma (n=7). The maximum dose to the AVP was ≤8.0 Gy (n=126), 8.1-10.0 Gy (n=39), 10.1-12.0 Gy (n=47), and >12 Gy (n=10). Results: The mean clinical and imaging follow-up periods were 83 and 123 months, respectively. One patient (0.5%) who received a maximum radiation dose of 12.8 Gy to the AVP developed unilateral blindness 18 months after SRS. The chance of RION according to the maximum radiation dose received by the AVP was 0 (95% confidence interval [CI] 0-3.6%), 0 (95% CI 0-10.7%), 0 (95% CI 0-9.0%), and 10% (95% CI 0-43.0%) for patients receiving ≤8 Gy, 8.1-10.0 Gy, 10.1-12.0 Gy, and >12 Gy, respectively. The overall risk of RION in patients receiving >8 Gy to the AVP was 1.0% (95% CI 0-6.2%). Conclusions: The risk of RION after single-fraction SRS in patients with benign skull base tumors who have no prior radiation exposure is very low if the maximum dose to the AVP is ≤12 Gy. Physicians performing single-fraction SRS should remain cautious when treating lesions adjacent to the AVP, especially when the maximum dose exceeds 10 Gy

Long-term Evaluation of Radiation-Induced Optic Neuropathy After Single-Fraction Stereotactic Radiosurgery

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Leavitt, Jacqueline A., E-mail: leavitt.jacqueline@mayo.edu [Department of Ophthalmology, Mayo Clinic and Foundation, Rochester, Minnesota (United States); Stafford, Scott L. [Department of Radiation Oncology, Mayo Clinic and Foundation, Rochester, Minnesota (United States); Link, Michael J. [Department of Neurosurgery, Mayo Clinic and Foundation, Rochester, Minnesota (United States); Pollock, Bruce E. [Department of Radiation Oncology, Mayo Clinic and Foundation, Rochester, Minnesota (United States); Department of Neurosurgery, Mayo Clinic and Foundation, Rochester, Minnesota (United States)

2013-11-01

Purpose: To determine the long-term risk of radiation-induced optic neuropathy (RION) in patients having single-fraction stereotactic radiosurgery (SRS) for benign skull base tumors. Methods and Materials: Retrospective review of 222 patients having Gamma Knife radiosurgery for benign tumors adjacent to the anterior visual pathway (AVP) between 1991 and 1999. Excluded were patients with prior or concurrent external beam radiation therapy or SRS. One hundred twenty-nine patients (58%) had undergone previous surgery. Tumor types included confirmed World Health Organization grade 1 or presumed cavernous sinus meningioma (n=143), pituitary adenoma (n=72), and craniopharyngioma (n=7). The maximum dose to the AVP was ≤8.0 Gy (n=126), 8.1-10.0 Gy (n=39), 10.1-12.0 Gy (n=47), and >12 Gy (n=10). Results: The mean clinical and imaging follow-up periods were 83 and 123 months, respectively. One patient (0.5%) who received a maximum radiation dose of 12.8 Gy to the AVP developed unilateral blindness 18 months after SRS. The chance of RION according to the maximum radiation dose received by the AVP was 0 (95% confidence interval [CI] 0-3.6%), 0 (95% CI 0-10.7%), 0 (95% CI 0-9.0%), and 10% (95% CI 0-43.0%) for patients receiving ≤8 Gy, 8.1-10.0 Gy, 10.1-12.0 Gy, and >12 Gy, respectively. The overall risk of RION in patients receiving >8 Gy to the AVP was 1.0% (95% CI 0-6.2%). Conclusions: The risk of RION after single-fraction SRS in patients with benign skull base tumors who have no prior radiation exposure is very low if the maximum dose to the AVP is ≤12 Gy. Physicians performing single-fraction SRS should remain cautious when treating lesions adjacent to the AVP, especially when the maximum dose exceeds 10 Gy.

Evaluation of the uncertainties in the TLD radiosurgery postal dose system

Science.gov (United States)

Campos, L. T.; Leite, S. P.; de Almeida, C. E. V.; Magalhães, L. A. G.

2018-03-01

Stereotactic radiosurgery is a single-fraction radiation therapy procedure for treating intracranial lesions using a stereotactic apparatus and multiple narrow beams delivered through noncoplanar isocentric arcs. To guarantee a high quality standard, a comprehensive Quality Assurance programme is extremely important to ensure that the measured dose is consistent with the tolerance considered to improve treatment quality. The Radiological Science Laboratory operates a postal audit programme in SRT and SRS. The purpose of the programme is to verify the target localization accuracy in known geometry and the dosimetric conditions of the TPS. The programme works in such a way those thermoluminescence dosimeters, consisting of LiF chips, are sent to the centre where they are to be irradiated to a certain dose. The TLD are then returned, where they are evaluated and the absorbed dose is obtained from TLDs readings. The aim of the present work is estimate the uncertainties in the process of dose determination, using experimental data.

Stereotactic radiosurgery and its potential in neurological practice: our first experience

International Nuclear Information System (INIS)

Vladarova, D.

1991-01-01

The history of radiosurgery of the brain, and experience with the use of beams of ionizing radiation in the therapy of intracranial tumors and arteriovenous malformations are dealt with. Leksell's gamma knife and the way of its use are described. Techniques of stereotactically directed narrow gamma beams with a steep radiation dose gradient serve to subject sharply bounded volumes of tissue to high radiation doses. Owing to a system of collimators, the effect of radiation on the surrounding tissues is negligible. The whole procedure, including the previous angiography and the corresponding calculations, takes 5 to 30 minutes. The latent time after the surgery during which a complete obliteration of the pathological blood vessels takes place is a drawback; this latent time is typically from 4 months to 2 years. World experience in the therapy by this method and the first two cases of patients in Czechoslovakia are described. (M.D.). 1 fig., 12 refs

Stereotactic Radiosurgery for Poor Performance Status Patients

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Kubicek, Gregory J., E-mail: kubicek-gregory@cooperhealth.edu [Department of Radiation Oncology, Cooper University Hospital, Camden, New Jersey (United States); Turtz, Alan [Department of Neurological Surgery, Cooper University Hospital, Camden, New Jersey (United States); Xue, Jinyu; Patel, Ashish; Richards, Gregory; LaCouture, Tamara [Department of Radiation Oncology, Cooper University Hospital, Camden, New Jersey (United States); Cappelli, Louis; Diestelkamp, Tim [Rowan Graduate School, Camden, New Jersey (United States); Saraiya, Piya [Department of Diagnostic Radiology, Cooper University Hospital, Camden, New Jersey (United States); Bexon, Anne [Department of Neurological Surgery, Cooper University Hospital, Camden, New Jersey (United States); Lerman, Nati [Department of Medical Oncology, Cooper University Hospital, Camden, New Jersey (United States); Goldman, Howard Warren [Department of Neurological Surgery, Cooper University Hospital, Camden, New Jersey (United States)

2016-07-01

Purpose: Patients with poor performance status (PS), usually defined as a Karnofsky Performance Status of 60 or less, were not eligible for randomized stereotactic radiosurgery (SRS) studies, and many guidelines suggest that whole-brain radiation therapy (WBRT) is the most appropriate treatment for poor PS patients. Methods and Materials: In this retrospective review of our SRS database, we identified 36 patients with PS of 60 or less treated with SRS for central nervous system (CNS) metastatic disease. PS, as defined by the Karnofsky Performance Status, was 60 (27 patients), 50 (8 patients), or 40 (1 patient). The median number of CNS lesions treated was 3. Results: Median overall survival (OS) was 7.2 months (range, 0.73-25.6 months). Fifteen patients (41%) were alive at 6 months, and 6 patients (16.6%) were alive at 1 year. There was no difference in OS in patients who underwent previous WBRT. There were no local failures or cases of radiation toxicity. Distant CNS failures were seen in 9 patients (25%). Conclusions: Our patients with poor PS had reasonable median OS and relatively low distant CNS failure rates. Patients in this patient population may be ideal candidates for SRS compared with WBRT given the low incidence of distant failure over their remaining lives and the favorable logistics of single-fraction treatment for these patients with debility and their caregivers.

Fractionated stereotactic radiation therapy and single high-dose radiosurgery for acoustic neuroma: early results of a prospective clinical study

International Nuclear Information System (INIS)

Meijer, O.W.M.; Wolbers, J.G.; Baayen, J.C.; Slotman, B.J.

2000-01-01

Purpose: To prospectively assess the local control and toxicity rate in acoustic neuroma patients treated with linear accelerator-based radiosurgery and fractionated stereotactic radiation therapy. Methods and Materials: We evaluated 37 consecutive patients treated with stereotactic radiation therapy for acoustic neuroma. All patients had progressive tumors, progressive symptoms, or both. Mean tumor diameter was 2.3 cm (range 0.8-3.3) on magnetic resonance (MR) scan. Dentate patients were given a dose of 5 x 4 Gy or 5 x 5 Gy and edentate patients were given a dose of 1 x 10 Gy or 1 x 12.50 Gy prescribed to the 80% isodose. All patients were treated with a single isocenter. Results: With a mean follow-up period of 25 months (range 12-61), the actuarial local control rate at 5 years was 91% (only 1 patient failed). The actuarial rate of hearing preservation at 5 years was 66% in previously-hearing patients. The actuarial rate of freedom from trigeminal nerve toxicity was 97% at 5 years. No patient developed facial nerve toxicity or other complications. Conclusion: In this unselected series, fractionated stereotactic radiation therapy and linear accelerator-based radiosurgery give excellent local control in acoustic neuroma. It combines a high rate of preservation of hearing with a very low rate of other toxicity, although follow-up is relatively short

Gamma Knife radiosurgery for intracranial meningiomas : Do we need to treat the dural tail? A single-center retrospective analysis and an overview of the literature

NARCIS (Netherlands)

Bulthuis, Vincent J; Hanssens, Patrick E J; Lie, Suan Te; van Overbeeke, Jacobus J

2014-01-01

BACKGROUND: The dural tail (DT) has been described as a common feature in meningiomas. There is a great variation of tumor invasion and extent of tumor cells in the DT. Therefore, the necessity to include the whole DT in Gamma Knife radiosurgery is not clear, since inclusion increases the target

Dose distribution close to metal implants in Gamma Knife Radiosurgery: A Monte Carlo study

International Nuclear Information System (INIS)

Cheung, Joel Y.C.; Yu, K.N.; Chan, Josie F.K.; Ho, Robert T.K.; Yu, C.P.

2003-01-01

Materials with high atomic numbers favor the occurrence of the photoelectric effect when they are irradiated with gamma rays. Therefore, the photoelectric effects of metal implants within the target regions in Gamma Knife Radiosurgery are worth studying. In the present work, Monte Carlo simulations using EGS4 were employed to investigate the resulting dose enhancements. A dose enhancement as high as 10% was observed close to a platinum implant along the x and y axes, while no significant dose enhancements were observed for silver, stainless steel 301, and titanium ones. A dose enhancement as high as 20% was observed close to the platinum implant along the z axis at the superior position of the metal-phantom interface and was 10% higher for other metal implants

Clinical results of stereotactic heavy-charged-particle radiosurgery for intracranial angiographically occult vascular malformations

International Nuclear Information System (INIS)

Levy, R.P.; Fabrikant, J.I.; Phillips, M.H.; Frankel, K.A.; Steinberg, G.K.; Marks, M.P.; DeLaPaz, R.L.; Chuang, F.Y.S.; Lyman, J.T.

1989-12-01

Angiographically occult vascular malformations (AOVMs) of the brain have been recognized for many years to cause neurologic morbidity and mortality. They generally become symptomatic due to intracranial hemorrhage, focal mass effect, seizures or headaches. The true incidence of AOVMs is unknown, but autopsy studies suggest that they are more common than high-flow angiographically demonstrable arteriovenous malformations (AVMs). We have developed stereotactic heavy-charged-particle Bragg peak radiosurgery for the treatment of inoperable intracranial vascular malformations, using the helium ion beams at the Lawrence Berkeley Laboratory 184-inch Synchrocyclotron and Bevatron. This report describes the protocol for patient selection, radiosurgical treatment planning method, clinical and neuroradiologic results and complications encountered, and discusses the strengths and limitations of the method. 10 refs., 1 fig

Clinical results of stereotactic heavy-charged-particle radiosurgery for intracranial angiographically occult vascular malformations

Energy Technology Data Exchange (ETDEWEB)

Levy, R.P.; Fabrikant, J.I.; Phillips, M.H.; Frankel, K.A.; Steinberg, G.K.; Marks, M.P.; DeLaPaz, R.L.; Chuang, F.Y.S.; Lyman, J.T.

1989-12-01

Angiographically occult vascular malformations (AOVMs) of the brain have been recognized for many years to cause neurologic morbidity and mortality. They generally become symptomatic due to intracranial hemorrhage, focal mass effect, seizures or headaches. The true incidence of AOVMs is unknown, but autopsy studies suggest that they are more common than high-flow angiographically demonstrable arteriovenous malformations (AVMs). We have developed stereotactic heavy-charged-particle Bragg peak radiosurgery for the treatment of inoperable intracranial vascular malformations, using the helium ion beams at the Lawrence Berkeley Laboratory 184-inch Synchrocyclotron and Bevatron. This report describes the protocol for patient selection, radiosurgical treatment planning method, clinical and neuroradiologic results and complications encountered, and discusses the strengths and limitations of the method. 10 refs., 1 fig.

Stereotactic radiosurgery vs. fractionated radiotherapy for tumor control in vestibular schwannoma patients: a systematic review.

Science.gov (United States)

Persson, Oscar; Bartek, Jiri; Shalom, Netanel Ben; Wangerid, Theresa; Jakola, Asgeir Store; Förander, Petter

2017-06-01

Repeated controlled studies have revealed that stereotactic radiosurgery is better than microsurgery for patients with vestibular schwannoma (VS) 18 years) patients with unilateral VS, followed for a median of >5 years, were eligible for inclusion. After screening titles and abstracts of the 1094 identified articles and systematically reviewing 98 of these articles, 19 were included. Patients with unilateral VS treated with radiosurgery were compared to patients treated with fractionated stereotactic radiotherapy. No randomized controlled trial (RCT) was identified. None of the identified controlled studies comparing SRS with FSRT were eligible according to the inclusion criteria. Nineteen case series on SRS (n = 17) and FSRT (n = 2) were included in the systematic review. Loss of tumor control necessitating a new VS-targeted intervention was found in an average of 5.0% of the patients treated with SRS and in 4.8% treated with FSRT. Mean deterioration ratio for patients with serviceable hearing before treatment was 49% for SRS and 45% for FSRT, respectively. The risk for facial nerve deterioration was 3.6% for SRS and 11.2% for FSRT and for trigeminal nerve deterioration 6.0% for SRS and 8.4% for FSRT. Since these results were obtained from case series, a regular meta-analysis was not attempted. SRS and FSRT are both noninvasive treatment alternatives for patients with VS with low rates of treatment failure in need of rescue therapy. In this selection of patients, the progression-free survival rates were on the order of 92-100% for both treatment options. There is a lack of high-quality studies comparing radiation therapy alternatives for patients with VS. Finally, 19 articles reported long-term tumor control after SRS, while only 2 articles reported long-term FSRT results, making effect estimates more uncertain for FSRT.

Volumetric changes and clinical outcome for petroclival meningiomas after primary treatment with Gamma Knife radiosurgery.

Science.gov (United States)

Sadik, Zjiwar H A; Lie, Suan Te; Leenstra, Sieger; Hanssens, Patrick E J

2018-01-26

OBJECTIVE Petroclival meningiomas (PCMs) can cause devastating clinical symptoms due to mass effect on cranial nerves (CNs); thus, patients harboring these tumors need treatment. Many neurosurgeons advocate for microsurgery because removal of the tumor can provide relief or result in symptom disappearance. Gamma Knife radiosurgery (GKRS) is often an alternative for surgery because it can cause tumor shrinkage with improvement of symptoms. This study evaluates qualitative volumetric changes of PCM after primary GKRS and its impact on clinical symptoms. METHODS The authors performed a retrospective study of patients with PCM who underwent primary GKRS between 2003 and 2015 at the Gamma Knife Center of the Elisabeth-Tweesteden Hospital in Tilburg, the Netherlands. This study yields 53 patients. In this study the authors concentrate on qualitative volumetric tumor changes, local tumor control rate, and the effect of the treatment on trigeminal neuralgia (TN). RESULTS Local tumor control was 98% at 5 years and 93% at 7 years (Kaplan-Meier estimates). More than 90% of the tumors showed regression in volume during the first 5 years. The mean volumetric tumor decrease was 21.2%, 27.1%, and 31% at 1, 3, and 6 years of follow-up, respectively. Improvement in TN was achieved in 61%, 67%, and 70% of the cases at 1, 2, and 3 years of follow-up, respectively. This was associated with a mean volumetric tumor decrease of 25% at the 1-year follow-up to 32% at the 3-year follow-up. CONCLUSIONS GKRS for PCMs yields a high tumor control rate with a low incidence of neurological deficits. Many patients with TN due to PCM experienced improvement in TN after radiosurgery. GKRS achieves significant volumetric tumor decrease in the first years of follow-up and thereafter.

Gamma Knife radiosurgery of olfactory groove meningiomas provides a method to preserve subjective olfactory function.

Science.gov (United States)

Gande, Abhiram; Kano, Hideyuki; Bowden, Gregory; Mousavi, Seyed H; Niranjan, Ajay; Flickinger, John C; Lunsford, L Dade

2014-02-01

Anosmia is a common outcome after resection of olfactory groove meningioma(s) (OGM) and for some patients represents a significant disability. To evaluate long term tumor control rates and preservation of subjective olfaction after Gamma Knife (GK) stereotactic radiosurgery (SRS) of OGM. We performed a retrospective chart review and telephone assessments of 41 patients who underwent GK SRS between 1987 and 2008. Clinical outcomes were stratified by full, partial or no subjective olfaction, whereas tumor control was assessed by changes in volume greater or lesser than 25%. The median clinical and imaging follow-up were 76 and 65 months, respectively. Prior to SRS, 19 (46%) patients had surgical resections and two (5%) had received fractionated radiation therapy. Twenty four patients (59%) reported a normal sense of smell, 12 (29%) reported a reduced sense of smell and five (12%) had complete anosmia. The median tumor volume was 8.5 cm(3) (range 0.6-56.1), the mean radiation dose at the tumor margin was 13 Gy (range 10-20) and the median estimated dose to the olfactory nerve was 5.1 Gy (range 1.1-18.1). At follow-up, 27 patients (66%) reported intact olfaction (three (7%) described return to a normal sense of smell), nine (22%) described partial anosmia, and five (12%) had complete anosmia. No patient reported deterioration in olfaction after SRS. Thirteen patients (32%) showed significant tumor regression, 26 (63%) had no further growth and two (5%) had progressed. The progression free tumor control rates were 97% at 1 year and 95% at 2, 10 and 20 years. Symptomatic adverse radiation effects occurred in three (7%) patients. Stereotactic radiosurgery provided both long term tumor control and preservation of olfaction.

Study of the absorbed dose in small fields with absence of lateral electronic balance in stereotactic radiosurgery and radiotherapy with modulated intensity

International Nuclear Information System (INIS)

Vargas V, M. X.

2013-01-01

In this thesis we develop and experimental and theoretical study, using semi analytical techniques of the physical dosimetry for small and nonstandard fields for stereotactic radiosurgery (Srs) and intensity modulated radiation therapy (IMRT), with high energy photon beams from a BrainLAB system with cones at Instituto del Cancer SOLCA (Ecuador) and a Tomo Therapy Hi-Art system at Centro Oncologico de Chihuahua (Mexico). (Author)

Clinical outcome of fiducial-less CyberKnife radiosurgery for stage I non-small cell lung cancer

International Nuclear Information System (INIS)

Jung, In Hye; Song, Si Yeol; Cho, Byung Chul; Kwak, Jung Won; Jung, Nuri Hyun; Kim, Su Ssan; Choi, Eun Kyung; Jung, Jin Hong; Je, Hyoung Uk; Choi, Won Sik

2015-01-01

To evaluate the treatment results in early stage non-small cell lung cancer patients who have undergone fiducial-less CyberKnife radiosurgery (CKRS). From June 2011 to November 2013, 58 patients underwent CKRS at Asan Medical Center for stage I lung cancer. After excluding 14 patients, we retrospectively reviewed the records of the remaining 44 patients. All analyses were performed using SPSS ver. 21. The median age at diagnosis was 75 years. Most patients had inoperable primary lung cancer with a poor pulmonary function test with comorbidity or old age. The clinical stage was IA in 30 patients (68.2%), IB in 14 (31.8%). The mean tumor size was 2.6 cm (range, 1.2 to 4.8 cm), and the tumor was smaller than 2 cm in 12 patients (27.3%). The radiation dose given was 48-60 Gy in 3-4 fractions. In a median follow-up of 23.1 months, local recurrence occurred in three patients (2-year local recurrence-free survival rate, 90.4%) and distant metastasis occurred in 13 patients. All patients tolerated the radiosurgery well, only two patients developing grade 3 dyspnea. The most common complications were radiation-induced fibrosis and pneumonitis. Eight patients died due to cancer progression. The results showed that fiducial-less CKRS shows comparable local tumor control and survival rates to those of LINAC-based SABR or CKRS with a fiducial marker. Thus, fiducial-less CKRS using Xsight lung tracking system can be effectively and safely performed for patients with medically inoperable stage I non-small cell lung cancer without any risk of procedure-related complication

Clinical outcome of fiducial-less CyberKnife radiosurgery for stage I non-small cell lung cancer

Energy Technology Data Exchange (ETDEWEB)

Jung, In Hye; Song, Si Yeol; Cho, Byung Chul; Kwak, Jung Won; Jung, Nuri Hyun; Kim, Su Ssan; Choi, Eun Kyung [Dept. of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Jung, Jin Hong [Dept. of Radiation Oncology, Kyung Hee University Medical Center, Kyung Hee University School of Medicine, Seoul (Korea, Republic of); Je, Hyoung Uk [Dept. of Radiation Oncology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan (Korea, Republic of); Choi, Won Sik [Dept. of Radiation Oncology, Gangneung Asan Hospital, Uiversity of Ulsan College of Medicine, Gangneung (Korea, Republic of)

2015-06-15

To evaluate the treatment results in early stage non-small cell lung cancer patients who have undergone fiducial-less CyberKnife radiosurgery (CKRS). From June 2011 to November 2013, 58 patients underwent CKRS at Asan Medical Center for stage I lung cancer. After excluding 14 patients, we retrospectively reviewed the records of the remaining 44 patients. All analyses were performed using SPSS ver. 21. The median age at diagnosis was 75 years. Most patients had inoperable primary lung cancer with a poor pulmonary function test with comorbidity or old age. The clinical stage was IA in 30 patients (68.2%), IB in 14 (31.8%). The mean tumor size was 2.6 cm (range, 1.2 to 4.8 cm), and the tumor was smaller than 2 cm in 12 patients (27.3%). The radiation dose given was 48-60 Gy in 3-4 fractions. In a median follow-up of 23.1 months, local recurrence occurred in three patients (2-year local recurrence-free survival rate, 90.4%) and distant metastasis occurred in 13 patients. All patients tolerated the radiosurgery well, only two patients developing grade 3 dyspnea. The most common complications were radiation-induced fibrosis and pneumonitis. Eight patients died due to cancer progression. The results showed that fiducial-less CKRS shows comparable local tumor control and survival rates to those of LINAC-based SABR or CKRS with a fiducial marker. Thus, fiducial-less CKRS using Xsight lung tracking system can be effectively and safely performed for patients with medically inoperable stage I non-small cell lung cancer without any risk of procedure-related complication.

Correlation between AQP4 mRNA and PKC activity after gamma knife radiosurgery in rat brain

International Nuclear Information System (INIS)

Shen Guangjian; Xu Minhui; Gen Mingying; Tang Wenyuan; Sun Shanquan

2009-01-01

Objective: To explore the change of AQP4 mRNA expression and the correlation with PKC in rat brain irradiated by γ knife radiosurgery (GKS). Methods: 30 Wistar rats were used in the study. The experimental radiosurgery model was established by radiating rat left rotral caudate nucleus with GKS(one target, 100 Gy in isocenter dose and 4 mm in collimator), and was examined at 1,3,7,15,30 and 45 d post-irradiation. AQP4 mRNA expression, PKC activity and free intracellular calcium ion concentration ([Ca 2+ ] i ) of brain tissue were determined by RT-PCR, liquid scintillation counter and Fura-2/AM, respectively. Results: AQP4 mRNA expression increased gradually from 0.99 ± 0.05 in control group to 2.32 ± 0.10 at 30 d post-irradiation, and decreased to 2.21 ± 0.08 at 45 d post-irradiation. The PKC activity and the free [Ca 2+ ] i decreased gradually from 0.5896 ± 0.2101 and 455.82 ± 20.13 in control group to 0.0404 ± 0.0294 and 196.72 ± 9.87 at 30 d post- irradiation, and increased to 0.1050 ± 0.0607 and 219.26 ± 10.43 at 45 d post-irradiation, respectively. The significant differences were found between experimental group and control group except at 1 d post-irradiation (P 2+ ] i and the PKC activity was positive (P=0.001, r=0.959). Conclusions: The increased expression of AQP4 mRNA might result from the inhibition of PKC activity due to the reduction of free [Ca 2+ ] i after GKS. (authors)

Prescription Dose Guideline Based on Physical Criterion for Multiple Metastatic Brain Tumors Treated With Stereotactic Radiosurgery

International Nuclear Information System (INIS)

Sahgal, Arjun; Barani, Igor J.; Novotny, Josef; Zhang Beibei; Petti, Paula; Larson, David A.; Ma Lijun

2010-01-01

Purpose: Existing dose guidelines for intracranial stereotactic radiosurgery (SRS) are primarily based on single-target treatment data. This study investigated dose guidelines for multiple targets treated with SRS. Methods and Materials: A physical model was developed to relate the peripheral isodose volume dependence on an increasing number of targets and prescription dose per target. The model was derived from simulated and clinical multiple brain metastatic cases treated with the Leksell Gamma Knife Perfexion at several institutions, where the total number of targets ranged from 2 to 60. The relative increase in peripheral isodose volumes, such as the 12-Gy volume, was studied in the multitarget treatment setting based on Radiation Therapy Oncology Group 90-05 study dose levels. Results: A significant increase in the 12-Gy peripheral isodose volumes was found in comparing multiple target SRS to single-target SRS. This increase strongly correlated (R 2 = 0.92) with the total number of targets but not the total target volumes (R 2 = 0.06). On the basis of the correlated curve, the 12-Gy volume for multiple target treatment was found to increase by approximately 1% per target when a low target dose such as 15 Gy was used, but approximately 4% per target when a high dose such as 20-24 Gy was used. Reduction in the prescription dose was quantified for each prescription level in maintaining the 12-Gy volume. Conclusion: Normal brain dose increases predictably with increasing number of targets for multitarget SRS. A reduction of approximately 1-2 Gy in the prescribed dose is needed compared with single target radiosurgery.

Treatment of absolute painful glaucoma with dynamic arcs using novalis shaped beam radiosurgery

International Nuclear Information System (INIS)

Gonzalez-Olhovich, Irene; Celis, Miguel Angel; Larraga-Gutierrez, Jose; Lopez-Ayala, Temuchino; Suarez-Campos, Jose; Garcia-Garduno, Amanda; Herrera-Gomez, Leopoldo; Hernandez-Bojorquez, Mariana B.Sc.

2006-01-01

Purpose: We assessed the effect of shaped beam conformal stereotactic radiosurgery (SRS) in 1 patient with chronic painful glaucoma in one eye refractory to medical treatment. Methods and Materials: Left eye ciliary body was targeted at 18 Gy (90% isodose curve) with a dedicated linear accelerator (Novalis, BrainLAB, Germany) SRS. Interval follow-up was performed weekly for the first month, and every 2 months until 1 year was completed with clinical examinations and intraocular pressure (IOP) measurements. Results: Ocular pain resolved at 6 weeks after SRS treatment. IOP decreased and normalized at 1 year. Conclusions: We present a case in which SRS appears to be an effective treatment of chronic refractory painful glaucoma. Further Phase I studies are needed to know the best parameters for radiation dose, tolerance of organs at risk, and pathophysiologic effects

Impact of Millimeter-Level Margins on Peripheral Normal Brain Sparing for Gamma Knife Radiosurgery

International Nuclear Information System (INIS)

Ma, Lijun; Sahgal, Arjun; Larson, David A.; Pinnaduwage, Dilini; Fogh, Shannon; Barani, Igor; Nakamura, Jean; McDermott, Michael; Sneed, Penny

2014-01-01

Purpose: To investigate how millimeter-level margins beyond the gross tumor volume (GTV) impact peripheral normal brain tissue sparing for Gamma Knife radiosurgery. Methods and Materials: A mathematical formula was derived to predict the peripheral isodose volume, such as the 12-Gy isodose volume, with increasing margins by millimeters. The empirical parameters of the formula were derived from a cohort of brain tumor and surgical tumor resection cavity cases (n=15) treated with the Gamma Knife Perfexion. This was done by first adding margins from 0.5 to 3.0 mm to each individual target and then creating for each expanded target a series of treatment plans of nearly identical quality as the original plan. Finally, the formula was integrated with a published logistic regression model to estimate the treatment-induced complication rate for stereotactic radiosurgery when millimeter-level margins are added. Results: Confirmatory correlation between the nominal target radius (ie, R T ) and commonly used maximum target size was found for the studied cases, except for a few outliers. The peripheral isodose volume such as the 12-Gy volume was found to increase exponentially with increasing Δ/R T , where Δ is the margin size. Such a curve fitted the data (logarithmic regression, R 2 >0.99), and the 12-Gy isodose volume was shown to increase steeply with a 0.5- to 3.0-mm margin applied to a target. For example, a 2-mm margin on average resulted in an increase of 55% ± 16% in the 12-Gy volume; this corresponded to an increase in the symptomatic necrosis rate of 6% to 25%, depending on the Δ/R T values for the target. Conclusions: Millimeter-level margins beyond the GTV significantly impact peripheral normal brain sparing and should be applied with caution. Our model provides a rapid estimate of such an effect, particularly for large and/or irregularly shaped targets

Hypopituitarism after stereotactic radiosurgery for pituitary adenomas.

Science.gov (United States)

Xu, Zhiyuan; Lee Vance, Mary; Schlesinger, David; Sheehan, Jason P

2013-04-01

Studies of new-onset Gamma Knife stereotactic radiosurgery (SRS)-induced hypopituitarism in large cohort of pituitary adenoma patients with long-term follow-up are lacking. We investigated the outcomes of SRS for pituitary adenoma patients with regard to newly developed hypopituitarism. This was a retrospective review of patients treated with SRS at the University of Virginia between 1994 and 2006. A total of 262 patients with a pituitary adenoma treated with SRS were reviewed. Thorough endocrine assessment was performed immediately before SRS and in regular follow-ups. Assessment consisted of 24-hour urine free cortisol (patients with Cushing disease), serum adrenocorticotropic hormone, cortisol, follicle-stimulating hormone, luteinizing hormone, insulin-like growth factor-1, growth hormone, testosterone (men), prolactin, thyroid-stimulating hormone, and free T(4). Endocrine remission occurred in 144 of 199 patients with a functioning adenoma. Tumor control rate was 89%. Eighty patients experienced at least 1 axis of new-onset SRS-induced hypopituitarism. The new hypopituitarism rate was 30% based on endocrine follow-up ranging from 6 to 150 months; the actuarial rate of new pituitary hormone deficiency was 31.5% at 5 years after SRS. On univariate and multivariate analyses, variables regarding the increased risk of hypopituitarism included suprasellar extension and higher radiation dose to the tumor margin; there were no correlations among tumor volume, prior transsphenoidal adenomectomy, prior radiation therapy, and age at SRS. SRS provides an effective and safe treatment option for patients with a pituitary adenoma. Higher margin radiation dose to the adenoma and suprasellar extension were 2 independent predictors of SRS-induced hypopituitarism.

Development of stereotactic radiosurgery using carbon beams (carbon-knife)

Science.gov (United States)

Keawsamur, Mintra; Matsumura, Akihiko; Souda, Hikaru; Kano, Yosuke; Torikoshi, Masami; Nakano, Takashi; Kanai, Tatsuaki

2018-02-01

The aim of this research is to develop a stereotactic-radiosurgery (SRS) technique using carbon beams to treat small intracranial lesions; we call this device the carbon knife. A 2D-scanning method is adapted to broaden a pencil beam to an appropriate size for an irradiation field. A Mitsubishi slow extraction using third order resonance through a rf acceleration system stabilized by a feed-forward scanning beam using steering magnets with a 290 MeV/u initial beam energy was used for this purpose. Ridge filters for spread-out Bragg peaks (SOBPs) with widths of 5 mm, 7.5 mm, and 10 mm were designed to include fluence-attenuation effects. The collimator, which defines field shape, was used to reduce the lateral penumbra. The lateral-penumbra width at the SOBP region was less than 2 mm for the carbon knife. The penumbras behaved almost the same when changing the air gap, but on the other hand, increasing the range-shifter thickness mostly broadened the lateral penumbra. The physical-dose rates were approximate 6 Gy s-1 and 4.5 Gy s-1 for the 10  ×  10 mm2 and 5  ×  5 mm2 collimators, respectively.

Cost-effectiveness Analysis of Stereotactic Radiosurgery Alone Versus Stereotactic Radiosurgery with Upfront Whole Brain Radiation Therapy for Brain Metastases.

Science.gov (United States)

Kim, H; Rajagopalan, M S; Beriwal, S; Smith, K J

2017-10-01

Stereotactic radiosurgery (SRS) alone or upfront whole brain radiation therapy (WBRT) plus SRS are the most commonly used treatment options for one to three brain oligometastases. The most recent randomised clinical trial result comparing SRS alone with upfront WBRT plus SRS (NCCTG N0574) has favoured SRS alone for neurocognitive function, whereas treatment options remain controversial in terms of cognitive decline and local control. The aim of this study was to conduct a cost-effectiveness analysis of these two competing treatments. A Markov model was constructed for patients treated with SRS alone or SRS plus upfront WBRT based on largely randomised clinical trials. Costs were based on 2016 Medicare reimbursement. Strategies were compared using the incremental cost-effectiveness ratio (ICER) and effectiveness was measured in quality-adjusted life years (QALYs). One-way and probabilistic sensitivity analyses were carried out. Strategies were evaluated from the healthcare payer's perspective with a willingness-to-pay threshold of $100 000 per QALY gained. In the base case analysis, the median survival was 9 months for both arms. SRS alone resulted in an ICER of $9917 per QALY gained. In one-way sensitivity analyses, results were most sensitive to variation in cognitive decline rates for both groups and median survival rates, but the SRS alone remained cost-effective for most parameter ranges. Based on the current available evidence, SRS alone was found to be cost-effective for patients with one to three brain metastases compared with upfront WBRT plus SRS. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Gamma Knife Radiosurgery Treatment for Metastatic Melanoma of the Trigeminal Nerve and Brainstem: A Case Report and a Review of the Literature

Science.gov (United States)

Peterson, Halloran E.; Larson, Erik W.; Fairbanks, Robert K.; Lamoreaux, Wayne T.; Mackay, Alexander R.; Call, Jason A.; Demakas, John J.; Cooke, Barton S.; Lee, Christopher M.

2013-01-01

Objective and Importance. Brainstem metastases (BSMs) are uncommon but serious complications of some cancers. They cause significant neurological deficit, and options for treatment are limited. Stereotactic radiosurgery (SRS) has been shown to be a safe and effective treatment for BSMs that prolongs survival and can preserve or in some cases improve neurological function. This case illustrates the use of repeated SRS, specifically Gamma Knife radiosurgery (GKRS) for management of a unique brainstem metastasis. Clinical Presentation. This patient presented 5 years after the removal of a lentigo maligna melanoma from her left cheek with left sided facial numbness and paresthesias with no reported facial weakness. Initial MRI revealed a mass on the left trigeminal nerve that appeared to be a trigeminal schwannoma. Intervention. After only limited response to the first GKRS treatment, a biopsy of the tumor revealed it to be metastatic melanoma, not schwannoma. Over the next two years, the patient would receive 3 more GKRS treatments. These procedures were effective in controlling growth in the treated areas, and the patient has maintained a good quality of life. Conclusion. GKRS has proven in this case to be effective in limiting the growth of this metastatic melanoma without acute adverse effects. PMID:24194991

Factors Predictive of Symptomatic Radiation Injury After Linear Accelerator-Based Stereotactic Radiosurgery for Intracerebral Arteriovenous Malformations

International Nuclear Information System (INIS)

Herbert, Christopher; Moiseenko, Vitali; McKenzie, Michael; Redekop, Gary; Hsu, Fred; Gete, Ermias; Gill, Brad; Lee, Richard; Luchka, Kurt; Haw, Charles; Lee, Andrew; Toyota, Brian; Martin, Montgomery

2012-01-01

Purpose: To investigate predictive factors in the development of symptomatic radiation injury after treatment with linear accelerator–based stereotactic radiosurgery for intracerebral arteriovenous malformations and relate the findings to the conclusions drawn by Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC). Methods and Materials: Archived plans for 73 patients who were treated at the British Columbia Cancer Agency were studied. Actuarial estimates of freedom from radiation injury were calculated using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards models were used for analysis of incidence of radiation injury. Log–rank test was used to search for dosimetric parameters associated with freedom from radiation injury. Results: Symptomatic radiation injury was exhibited by 14 of 73 patients (19.2%). Actuarial rate of symptomatic radiation injury was 23.0% at 4 years. Most patients (78.5%) had mild to moderate deficits according to Common Terminology Criteria for Adverse Events, version 4.0. On univariate analysis, lesion volume and diameter, dose to isocenter, and a V x for doses ≥8 Gy showed statistical significance. Only lesion diameter showed statistical significance (p 5 cm 3 and diameters >30 mm were significantly associated with the risk of radiation injury (p 12 also showed strong association with the incidence of radiation injury. Actuarial incidence of radiation injury was 16.8% if V 12 was 3 and 53.2% if >28 cm 3 (log–rank test, p = 0.001). Conclusions: This study confirms that the risk of developing symptomatic radiation injury after radiosurgery is related to lesion diameter and volume and irradiated volume. Results suggest a higher tolerance than proposed by QUANTEC. The widely differing findings reported in the literature, however, raise considerable uncertainties.

Characterisation of a plastic scintillation detector to be used in a multicentre stereotactic radiosurgery dosimetry audit

Science.gov (United States)

Dimitriadis, A.; Patallo, I. Silvestre; Billas, I.; Duane, S.; Nisbet, A.; Clark, C. H.

2017-11-01

Scintillation detectors are considered highly suitable for dosimetric measurement of small fields in radiotherapy due to their near-tissue equivalence and their small size. A commercially available scintillation detector, the Exradin W1 (Standard Imaging, Middleton, USA), has been previously characterised by two independent studies (Beierholm et al., 2014; Carrasco et al., 2015a, 2015b) but the results from these publications differed in some aspects (e.g. energy dependence, long term stability). The respective authors highlighted the need for more studies to be published (Beierholm et al., 2015; Carrasco et al., 2015a, 2015b). In this work, the Exradin W1 was characterised in terms of dose response, dependence on dose rate, energy, temperature and angle of irradiation, and long-term stability. The observed dose linearity, short-term repeatability and temperature dependence were in good agreement with previously published data. Appropriate corrections should therefore be applied, where possible, in order to achieve measurements with low-uncertainty. The angular dependence was characterised along both the symmetrical and polar axis of the detector for the first time in this work and a dose variation of up to 1% was observed. The response of the detector was observed to decrease at a rate of approximately 1.6% kGy-1 for the first 5 kGy delivered, and then stabilised to 0.2% kGy-1 in the subsequent 20 kGy. The main goal of this work was to assess the suitability of the Exradin W1 for use in dose verification measurements for stereotactic radiosurgery. The results obtained confirm that the detector is suitable for use in such situations. The detector is now utilised in a multi-centre stereotactic radiosurgery dosimetric audit, with the application of appropriate correction factors.

Factors Predictive of Symptomatic Radiation Injury After Linear Accelerator-Based Stereotactic Radiosurgery for Intracerebral Arteriovenous Malformations

Energy Technology Data Exchange (ETDEWEB)

Herbert, Christopher, E-mail: cherbert@bccancer.bc.ca [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, BC (Canada); Moiseenko, Vitali [Department of Medical Physics, British Columbia Cancer Agency, Vancouver, BC (Canada); McKenzie, Michael [Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, BC (Canada); Redekop, Gary [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Hsu, Fred [Department of Radiation Oncology, British Columbia Cancer Agency, Abbotsford, BC (Canada); Gete, Ermias; Gill, Brad; Lee, Richard; Luchka, Kurt [Department of Medical Physics, British Columbia Cancer Agency, Vancouver, BC (Canada); Haw, Charles [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Lee, Andrew [Department of Neurosurgery, Royal Columbian Hospital, New Westminster, BC (Canada); Toyota, Brian [Division of Neurosurgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC (Canada); Martin, Montgomery [Department of Medical Imaging, British Columbia Cancer Agency, Vancouver, BC (Canada)

2012-07-01

Purpose: To investigate predictive factors in the development of symptomatic radiation injury after treatment with linear accelerator-based stereotactic radiosurgery for intracerebral arteriovenous malformations and relate the findings to the conclusions drawn by Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC). Methods and Materials: Archived plans for 73 patients who were treated at the British Columbia Cancer Agency were studied. Actuarial estimates of freedom from radiation injury were calculated using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards models were used for analysis of incidence of radiation injury. Log-rank test was used to search for dosimetric parameters associated with freedom from radiation injury. Results: Symptomatic radiation injury was exhibited by 14 of 73 patients (19.2%). Actuarial rate of symptomatic radiation injury was 23.0% at 4 years. Most patients (78.5%) had mild to moderate deficits according to Common Terminology Criteria for Adverse Events, version 4.0. On univariate analysis, lesion volume and diameter, dose to isocenter, and a V{sub x} for doses {>=}8 Gy showed statistical significance. Only lesion diameter showed statistical significance (p < 0.05) in a multivariate model. According to the log-rank test, AVM volumes >5 cm{sup 3} and diameters >30 mm were significantly associated with the risk of radiation injury (p < 0.01). The V{sub 12} also showed strong association with the incidence of radiation injury. Actuarial incidence of radiation injury was 16.8% if V{sub 12} was <28 cm{sup 3} and 53.2% if >28 cm{sup 3} (log-rank test, p = 0.001). Conclusions: This study confirms that the risk of developing symptomatic radiation injury after radiosurgery is related to lesion diameter and volume and irradiated volume. Results suggest a higher tolerance than proposed by QUANTEC. The widely differing findings reported in the literature, however, raise considerable uncertainties.

Novel biomarker identification using metabolomic profiling to differentiate radiation necrosis and recurrent tumor following Gamma Knife radiosurgery.

Science.gov (United States)

Lu, Alex Y; Turban, Jack L; Damisah, Eyiyemisi C; Li, Jie; Alomari, Ahmed K; Eid, Tore; Vortmeyer, Alexander O; Chiang, Veronica L

2017-08-01

OBJECTIVE Following an initial response of brain metastases to Gamma Knife radiosurgery, regrowth of the enhancing lesion as detected on MRI may represent either radiation necrosis (a treatment-related inflammatory change) or recurrent tumor. Differentiation of radiation necrosis from tumor is vital for management decision making but remains difficult by imaging alone. In this study, gas chromatography with time-of-flight mass spectrometry (GC-TOF) was used to identify differential metabolite profiles of the 2 tissue types obtained by surgical biopsy to find potential targets for noninvasive imaging. METHODS Specimens of pure radiation necrosis and pure tumor obtained from patient brain biopsies were flash-frozen and validated histologically. These formalin-free tissue samples were then analyzed using GC-TOF. The metabolite profiles of radiation necrosis and tumor samples were compared using multivariate and univariate statistical analysis. Statistical significance was defined as p ≤ 0.05. RESULTS For the metabolic profiling, GC-TOF was performed on 7 samples of radiation necrosis and 7 samples of tumor. Of the 141 metabolites identified, 17 (12.1%) were found to be statistically significantly different between comparison groups. Of these metabolites, 6 were increased in tumor, and 11 were increased in radiation necrosis. An unsupervised hierarchical clustering analysis found that tumor had elevated levels of metabolites associated with energy metabolism, whereas radiation necrosis had elevated levels of metabolites that were fatty acids and antioxidants/cofactors. CONCLUSIONS To the authors' knowledge, this is the first tissue-based metabolomics study of radiation necrosis and tumor. Radiation necrosis and recurrent tumor following Gamma Knife radiosurgery for brain metastases have unique metabolite profiles that may be targeted in the future to develop noninvasive metabolic imaging techniques.

Predictors of Distant Brain Recurrence for Patients With Newly Diagnosed Brain Metastases Treated With Stereotactic Radiosurgery Alone

International Nuclear Information System (INIS)

Sawrie, Stephen M.; Guthrie, Barton L.; Spencer, Sharon A.; Nordal, Robert A.; Meredith, Ruby F.; Markert, James M.; Cloud, Gretchen A.; Fiveash, John B.

2008-01-01

Purpose: To ascertain predictors of distant brain failure (DBF) in patients treated initially with stereotactic radiosurgery alone for newly diagnosed brain metastases. We hypothesize that these factors may be used to group patients according to risk of DBF. Methods and Materials: We retrospectively analyzed 100 patients with newly diagnosed brain metastases treated from 2003 to 2005 at our Gamma Knife radiosurgery facility. The primary endpoint was DBF. Potential predictors included number of metastases, tumor volume, histologic characteristics, extracranial disease, and use of temozolomide. Results: One-year actuarial risk of DBF was 61% for all patients. Significant predictors of DBF included more than three metastases (hazard ratio, 3.30; p = 0.004), stable or poorly controlled extracranial disease (hazard ratio, 2.16; p = 0.04), and melanoma histologic characteristics (hazard ratio, 2.14; p = 0.02). These were confirmed in multivariate analysis. Those with three or fewer metastases, no extracranial disease, and nonmelanoma histologic characteristics (N = 18) had a median time to DBF of 89 weeks vs. 33 weeks for all others. One-year actuarial freedom from DBF for this group was 83% vs. 26% for all others. Conclusions: Independent significant predictors of DBF in our series included number of metastases (more than three), present or uncontrolled extracranial disease, and melanoma histologic characteristics. These factors were combined to identify a lower risk subgroup with significantly longer time to DBF. These patients may be candidates for initial localized treatment, reserving whole-brain radiation therapy for salvage. Patients in the higher risk group may be candidates for initial whole-brain radiation therapy or should be considered for clinical trials

Prediction of new brain metastases after radiosurgery: validation and analysis of performance of a multi-institutional nomogram.

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Ayala-Peacock, Diandra N; Attia, Albert; Braunstein, Steve E; Ahluwalia, Manmeet S; Hepel, Jaroslaw; Chung, Caroline; Contessa, Joseph; McTyre, Emory; Peiffer, Ann M; Lucas, John T; Isom, Scott; Pajewski, Nicholas M; Kotecha, Rupesh; Stavas, Mark J; Page, Brandi R; Kleinberg, Lawrence; Shen, Colette; Taylor, Robert B; Onyeuku, Nasarachi E; Hyde, Andrew T; Gorovets, Daniel; Chao, Samuel T; Corso, Christopher; Ruiz, Jimmy; Watabe, Kounosuke; Tatter, Stephen B; Zadeh, Gelareh; Chiang, Veronica L S; Fiveash, John B; Chan, Michael D

2017-11-01

Stereotactic radiosurgery (SRS) without whole brain radiotherapy (WBRT) for brain metastases can avoid WBRT toxicities, but with risk of subsequent distant brain failure (DBF). Sole use of number of metastases to triage patients may be an unrefined method. Data on 1354 patients treated with SRS monotherapy from 2000 to 2013 for new brain metastases was collected across eight academic centers. The cohort was divided into training and validation datasets and a prognostic model was developed for time to DBF. We then evaluated the discrimination and calibration of the model within the validation dataset, and confirmed its performance with an independent contemporary cohort. Number of metastases (≥8, HR 3.53 p = 0.0001), minimum margin dose (HR 1.07 p = 0.0033), and melanoma histology (HR 1.45, p = 0.0187) were associated with DBF. A prognostic index derived from the training dataset exhibited ability to discriminate patients' DBF risk within the validation dataset (c-index = 0.631) and Heller's explained relative risk (HERR) = 0.173 (SE = 0.048). Absolute number of metastases was evaluated for its ability to predict DBF in the derivation and validation datasets, and was inferior to the nomogram. A nomogram high-risk threshold yielding a 2.1-fold increased need for early WBRT was identified. Nomogram values also correlated to number of brain metastases at time of failure (r = 0.38, p < 0.0001). We present a multi-institutionally validated prognostic model and nomogram to predict risk of DBF and guide risk-stratification of patients who are appropriate candidates for radiosurgery versus upfront WBRT.

Treatment of benign brain lesions True Beam radiosurgery in the first year of experience; Tratamiento de lesiones cerebrales benignas con radiocirugia en el True-Beam: Primer ano de experiencia

Energy Technology Data Exchange (ETDEWEB)

Lliso, F.; Carmona, V.; Gimeno, J.; Candela, C.; Bautista, J. A.; Perez-Calatayud, J.

2015-07-01

The purpose of the work is analyse the first year of experience in the treatment of injury brain benign with Rapid Arc in the patients treated in a throttle True Beam STX with radiosurgery who achieved an adequate level of efficiency and accuracy. (Author)

Initial clinical experience with frameless radiosurgery for patients with intracranial metastases

International Nuclear Information System (INIS)

Kamath, Reena; Ryken, Timothy C.; Meeks, Sanford L.; Pennington, Edward C.; Ritchie, Justine; Buatti, John M.

2005-01-01

Purpose: To review the initial clinical experience with frameless stereotactic radiosurgery (SRS) for treating intracranial metastatic disease. Methods and Materials: Sixty-four patients received frameless SRS for intracranial metastatic disease. Minimum follow-up was 6 months with none lost to follow-up. Patients had a median of 2 metastases and a maximum of 4. The median number of isocenters was 2 with median arcs of 10 and median dose of 17.5 Gy. Thirteen patients were treated for progressive/recurrent disease after surgical resection or whole brain radiotherapy (WBRT). Fifty-one patients were treated with frameless SRS as an an adjunct to initial treatment. Of the total treated, 17 were treated with SRS alone, 20 were treated with WBRT plus SRS, 16 were treated with surgical resection plus SRS, and the remaining 11 were treated with surgical resection plus WBRT plus SRS. Results: With a median actuarial follow-up period of 8.2 months, ultimate local control was 88%. The median time to progression was 8.1 months. The median overall survival was 8.7 months. Of the 17 patients treated with SRS alone, 86% had ultimate local control with mean overall survival of 7.1 months. Of the 13 patients who received surgical resection plus SRS without WBRT as primary treatment, there was 85% ultimate local control with an overall survival of 10.3 months. Three patients treated with initial surgery alone had recurrence treated with SRS 2-3 months after resection. All these patients obtained local control and median survival was >10 months. Of the 13 patients who received WBRT followed by SRS as boost treatment, 92% had local control and mean overall survival was 7.3 months. Of 7 patients who received SRS after recurrence after WBRT, 100% had local control with median survival of 8.2 months. For 8 patients who received surgery followed by WBRT and SRS, local control was 50%; however, ultimate intracranial control was achieved in 7 of 8 patients with repeat SRS and surgical

Effect of Gamma Knife Radiosurgery and Programmed Cell Death 1 Receptor Antagonists on Metastatic Melanoma

Science.gov (United States)

Hubbard, Molly; Nordmann, Tyler; Sperduto, Paul W; Clark, H. Brent; Hunt, Matthew A

2017-01-01

Learning objectives To evaluate radiation-induced changes in patients with brain metastasis secondary to malignant melanoma who received treatment with Gamma Knife radiosurgery (GKRS) and programmed cell death 1 (PD-1) receptor antagonists. Introduction  Stereotactic radiosurgery and chemotherapeutics are used together for treatment of metastatic melanoma and have been linked to delayed radiation-induced vasculitic leukoencephalopathy (DRIVL). There have been reports of more intense interactions with new immunotherapeutics targeting PD-1 receptors, but their interactions have not been well described and may result in an accelerated response to GKRS. Here we present data on subjects treated with this combination from a single institution. Methods Records from patients who underwent treatment for metastatic melanoma to the brain with GKRS from 2011 to 2016 were reviewed. Demographics, date of brain metastasis diagnosis, cause of death when applicable, immunotherapeutics, and imaging findings were recorded. The timing of radiation therapy and medications were also documented.  Results A total of 79 subjects were treated with GKRS, and 66 underwent treatment with both GKRS and immunotherapy. Regarding the 30 patients treated with anti-PD-1 immunotherapy, 21 patients received pembrolizumab, seven patients received nivolumab, and two patients received pembrolizumab and nivolumab. Serial imaging was available for interpretation in 25 patients, with 13 subjects who received GKRS and anti-PD-1 immunotherapy less than six weeks of each other. While four subjects had indeterminate/mixed findings on subsequent magnetic resonance imaging (MRI), nine subjects were noted to have progression. Two of these patients showed progression but subsequent imaging revealed a decrease in progression or improvement on MRI to previously targeted lesions by GKRS. None of the 13 subjects had surgery following their combined therapies. Conclusions This data suggests that there is need for