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  1. Proton Therapy

    Science.gov (United States)

    ... IMRT) Brain Tumor Treatment Brain Tumors Prostate Cancer Lung Cancer Treatment Lung Cancer Head and Neck Cancer Images related to Proton Therapy Videos related to Proton Therapy Sponsored by Please ...

  2. Proton Therapy

    Science.gov (United States)

    Oelfke, Uwe

    Proton therapy is one of the most rapidly developing new treatment technologies in radiation oncology. This treatment approach has — after roughly 40 years of technical developments — reached a mature state that allows a widespread clinical application. We therefore review the basic physical and radio-biological properties of proton beams. The main physical aspect is the elemental dose distribution arising from an infinitely narrow proton pencil beam. This includes the physics of proton stopping powers and the concept of CSDA range. Furthermore, the process of multiple Coulomb scattering is discussed for the lateral dose distribution. Next, the basic terms for the description of radio-biological properties of proton beams like LET and RBE are briefly introduced. Finally, the main concepts of modern proton dose delivery concepts are introduced before the standard method of inverse treatment planning for hadron therapy is presented.

  3. Proton therapy

    Science.gov (United States)

    ... TF. Charged particle radiotherapy. In: Gunderson LL, Tepper JE, eds. Gunderson and Tepper: Clinical Radiation Oncology . 4th ... March 22, 2017. Zeman EM, Schreiber EC, Tepper JE. Basics of radiation therapy. In: Niederhuber JE, Armitage ...

  4. Proton therapy physics

    CERN Document Server

    2012-01-01

    Proton Therapy Physics goes beyond current books on proton therapy to provide an in-depth overview of the physics aspects of this radiation therapy modality, eliminating the need to dig through information scattered in the medical physics literature. After tracing the history of proton therapy, the book summarizes the atomic and nuclear physics background necessary for understanding proton interactions with tissue. It describes the physics of proton accelerators, the parameters of clinical proton beams, and the mechanisms to generate a conformal dose distribution in a patient. The text then covers detector systems and measuring techniques for reference dosimetry, outlines basic quality assurance and commissioning guidelines, and gives examples of Monte Carlo simulations in proton therapy. The book moves on to discussions of treatment planning for single- and multiple-field uniform doses, dose calculation concepts and algorithms, and precision and uncertainties for nonmoving and moving targets. It also exami...

  5. Proton beam therapy facility

    Energy Technology Data Exchange (ETDEWEB)

    1984-10-09

    It is proposed to build a regional outpatient medical clinic at the Fermi National Accelerator Laboratory (Fermilab), Batavia, Illinois, to exploit the unique therapeutic characteristics of high energy proton beams. The Fermilab location for a proton therapy facility (PTF) is being chosen for reasons ranging from lower total construction and operating costs and the availability of sophisticated technical support to a location with good access to patients from the Chicago area and from the entire nation. 9 refs., 4 figs., 26 tabs.

  6. Proton therapy in clinical practice

    Science.gov (United States)

    Liu, Hui; Chang, Joe Y.

    2011-01-01

    Radiation dose escalation and acceleration improves local control but also increases toxicity. Proton radiation is an emerging therapy for localized cancers that is being sought with increasing frequency by patients. Compared with photon therapy, proton therapy spares more critical structures due to its unique physics. The physical properties of a proton beam make it ideal for clinical applications. By modulating the Bragg peak of protons in energy and time, a conformal radiation dose with or without intensity modulation can be delivered to the target while sparing the surrounding normal tissues. Thus, proton therapy is ideal when organ preservation is a priority. However, protons are more sensitive to organ motion and anatomy changes compared with photons. In this article, we review practical issues of proton therapy, describe its image-guided treatment planning and delivery, discuss clinical outcome for cancer patients, and suggest challenges and the future development of proton therapy. PMID:21527064

  7. Proton therapy in clinical practice

    Institute of Scientific and Technical Information of China (English)

    Hui Liu; Joe Y. Chang

    2011-01-01

    Radiation dose escalation and acceleration improves local control but also increases toxicity. Proton radiation is an emerging therapy for localized cancers that is being sought with increasing frequency by patients. Compared with photon therapy, proton therapy spares more critical structures due to its unique physics. The physical properties of a proton beam make it ideal for clinical applications. By modulating the Bragg peak of protons in energy and time, a conformal radiation dose with or without intensity modulation can be delivered to the target while sparing the surrounding normal tissues. Thus, proton therapy is ideal when organ preservation is a priority. However, protons are more sensitive to organ motion and anatomy changes compared with photons. In this article, we review practical issues of proton therapy, describe its image-guided treatment planning and delivery, discuss clinical outcome for cancer patients, and suggest challenges and the future development of proton therapy.

  8. Proton and carbon ion therapy

    CERN Document Server

    Lomax, Tony

    2013-01-01

    Proton and Carbon Ion Therapy is an up-to-date guide to using proton and carbon ion therapy in modern cancer treatment. The book covers the physics and radiobiology basics of proton and ion beams, dosimetry methods and radiation measurements, and treatment delivery systems. It gives practical guidance on patient setup, target localization, and treatment planning for clinical proton and carbon ion therapy. The text also offers detailed reports on the treatment of pediatric cancers, lymphomas, and various other cancers. After an overview, the book focuses on the fundamental aspects of proton and carbon ion therapy equipment, including accelerators, gantries, and delivery systems. It then discusses dosimetry, biology, imaging, and treatment planning basics and provides clinical guidelines on the use of proton and carbon ion therapy for the treatment of specific cancers. Suitable for anyone involved with medical physics and radiation therapy, this book offers a balanced and critical assessment of state-of-the-art...

  9. Proton therapy in the clinic.

    Science.gov (United States)

    DeLaney, Thomas F

    2011-01-01

    The clinical advantage for proton radiotherapy over photon approaches is the marked reduction in integral dose to the patient, due to the absence of exit dose beyond the proton Bragg peak. The integral dose with protons is approximately 60% lower than that with any external beam photon technique. Pediatric patients, because of their developing normal tissues and anticipated length of remaining life, are likely to have the maximum clinical gain with the use of protons. Proton therapy may also allow treatment of some adult tumors to much more effective doses, because of normal tissue sparing distal to the tumor. Currently, the most commonly available proton treatment technology uses 3D conformal approaches based on (a) distal range modulation, (b) passive scattering of the proton beam in its x- and y-axes, and (c) lateral beam-shaping. It is anticipated that magnetic pencil beam scanning will become the dominant mode of proton delivery in the future, which will lower neutron scatter associated with passively scattered beam lines, reduce the need for expensive beam-shaping devices, and allow intensity-modulated proton radiotherapy. Proton treatment plans are more sensitive to variations in tumor size and normal tissue changes over the course of treatment than photon plans, and it is expected that adaptive radiation therapy will be increasingly important for proton therapy as well. While impressive treatment results have been reported with protons, their cost is higher than for photon IMRT. Hence, protons should ideally be employed for anatomic sites and tumors not well treated with photons. While protons appear cost-effective for pediatric tumors, their cost-effectiveness for treatment of some adult tumors, such as prostate cancer, is uncertain. Comparative studies have been proposed or are in progress to more rigorously assess their value for a variety of sites. The utility of proton therapy will be enhanced by technological developments that reduce its cost

  10. Proton-therapy, present status.

    Science.gov (United States)

    Salvadori, R P; Rembado, D; Serrato, R

    1993-06-01

    At the moment, proton-therapy is the most advanced radiotherapeutic technique in cancer treatment. The use of the high energy proton beam (from 70 MeV to 200 MeV) lets a Bragg's peak be moved to different depths, so allowing personal radiotherapeutic treatment. In recent years, many proton-therapy centers have grown up throughout the world with very satisfactory clinical results, first of all in eye melanoma treatment. The future expectations are very promising, even if the very high installation and maintenance expenses of a synchrotron (for proton production) hinder the development of such a method.

  11. Proton therapy - Present and future.

    Science.gov (United States)

    Mohan, Radhe; Grosshans, David

    2017-01-15

    In principle, proton therapy offers a substantial clinical advantage over conventional photon therapy. This is because of the unique depth-dose characteristics of protons, which can be exploited to achieve significant reductions in normal tissue doses proximal and distal to the target volume. These may, in turn, allow escalation of tumor doses and greater sparing of normal tissues, thus potentially improving local control and survival while at the same time reducing toxicity and improving quality of life. Protons, accelerated to therapeutic energies ranging from 70 to 250MeV, typically with a cyclotron or a synchrotron, are transported to the treatment room where they enter the treatment head mounted on a rotating gantry. The initial thin beams of protons are spread laterally and longitudinally and shaped appropriately to deliver treatments. Spreading and shaping can be achieved by electro-mechanical means to treat the patients with "passively-scattered proton therapy" (PSPT) or using magnetic scanning of thin "beamlets" of protons of a sequence of initial energies. The latter technique can be used to treat patients with optimized intensity modulated proton therapy (IMPT), the most powerful proton modality. Despite the high potential of proton therapy, the clinical evidence supporting the broad use of protons is mixed. It is generally acknowledged that proton therapy is safe, effective and recommended for many types of pediatric cancers, ocular melanomas, chordomas and chondrosarcomas. Although promising results have been and continue to be reported for many other types of cancers, they are based on small studies. Considering the high cost of establishing and operating proton therapy centers, questions have been raised about their cost effectiveness. General consensus is that there is a need to conduct randomized trials and/or collect outcomes data in multi-institutional registries to unequivocally demonstrate the advantage of protons. Treatment planning and plan

  12. Proton therapy for Hodgkin lymphoma.

    Science.gov (United States)

    Rutenberg, Michael S; Flampouri, Stella; Hoppe, Bradford S

    2014-09-01

    Hodgkin lymphoma has gone from an incurable disease to one for which the majority of patients will be cured. Combined chemotherapy and radiotherapy achieves the best disease control rates and results in many long-term survivors. As a result, a majority of long-term Hodgkin lymphoma survivors live to experience severe late treatment-related complications, especially cardiovascular disease and second malignancies. The focus of research and treatment for Hodgkin lymphoma is to maintain the current high rates of disease control while reducing treatment-related morbidity and mortality. Efforts to reduce late treatment complications focus on improvements in both systemic therapies and radiotherapy. Herein we review the basis for the benefits of proton therapy over conventional X-ray therapy. We review outcomes of Hodgkin lymphoma treated with proton therapy, and discuss the ability of protons to reduce radiation dose to organs at risk and the impact on the most significant late complications related to the treatment.

  13. Proton therapy for pancreatic cancer

    Institute of Scientific and Technical Information of China (English)

    Romaine; C; Nichols; Soon; Huh; Zuofeng; Li; Michael; Rutenberg

    2015-01-01

    Radiotherapy is commonly offered to patients with pancreatic malignancies although its ultimate utility is compromised since the pancreas is surrounded by exquisitely radiosensitive normal tissues, such as the duodenum, stomach, jejunum, liver, and kidneys. Proton radiotherapy can be used to create dose distributions that conform to tumor targets with significant normal tissue sparing. Because of this, protons appear to represent a superior modality for radiotherapy delivery to patients with unresectable tumors and those receiving postoperative radiotherapy. A particularly exciting opportunity for protons also exists for patients with resectable and marginally resectable disease. In this paper, we review the current literature on proton therapy for pancreatic cancer and discuss scenarios wherein the improvement in the therapeutic index with protons may have the potential to change the management paradigm for this malignancy.

  14. Proton therapy of hypophyseal adenomas

    Energy Technology Data Exchange (ETDEWEB)

    Mirakova, E.I.; Kirpatovskaya, L.E.; Lyass, F.M.; Snigireva, R.Ya.; Krymskij, V.A. (Akademiya Meditsinskikh Nauk SSSR, Moscow. Inst. Nejrokhirurgii; Akademiya Meditsinskikh Nauk SSSR, Moscow. Inst. Ehksperimental' noj Ehndokrinologii i Khimii Gormonov)

    1983-10-01

    The authors present the results of proton therapy in 59 patients with different hypophyseal adenomas. The period of observation lasted from 6 mos. to 5 yrs. Irradiation was done using a multifield-convergent method and a proton beam of the ITEF synchrotron. The beam energy was 200 MeV, the beam diameter 7-15 mm. Radiation response and immediate results were evaluated for all the patients. The least favorable results were noted in the patients with prolactinomas, for which, in addition to irradiation, parlodel therapy is needed. No marked radiation reactions, neurological complications and manifestations of hypopituitarism were observed with the chosen doses and schemes of irradiation.

  15. Proton radiography to improve proton therapy treatment

    NARCIS (Netherlands)

    Takatsu, J.; van der Graaf, E. R.; Van Goethem, M. -J.; van Beuzekom, M.; Klaver, T.; Visser, J.; Brandenburg, S.; Biegun, A. K.

    2016-01-01

    The quality of cancer treatment with protons critically depends on an accurate prediction of the proton stopping powers for the tissues traversed by the protons. Today, treatment planning in proton radiotherapy is based on stopping power calculations from densities of X-ray Computed Tomography (CT)

  16. Emerging technologies in proton therapy

    NARCIS (Netherlands)

    Schippers, Jacobus M.; Lomax, Antony J.

    An increasing number of proton therapy facilities are being planned and built at hospital based centers. Most facilities are employing traditional dose delivery methods. A second generation of dose application techniques, based on pencil beam scanning, is slowly being introduced into the

  17. Proton radiography to improve proton therapy treatment

    Science.gov (United States)

    Takatsu, J.; van der Graaf, E. R.; Van Goethem, M.-J.; van Beuzekom, M.; Klaver, T.; Visser, J.; Brandenburg, S.; Biegun, A. K.

    2016-01-01

    The quality of cancer treatment with protons critically depends on an accurate prediction of the proton stopping powers for the tissues traversed by the protons. Today, treatment planning in proton radiotherapy is based on stopping power calculations from densities of X-ray Computed Tomography (CT) images. This causes systematic uncertainties in the calculated proton range in a patient of typically 3-4%, but can become even 10% in bone regions [1,2,3,4,5,6,7,8]. This may lead to no dose in parts of the tumor and too high dose in healthy tissues [1]. A direct measurement of proton stopping powers with high-energy protons will allow reducing these uncertainties and will improve the quality of the treatment. Several studies have shown that a sufficiently accurate radiograph can be obtained by tracking individual protons traversing a phantom (patient) [4,6,10]. Our studies benefit from the gas-filled time projection chambers based on GridPix technology [2], developed at Nikhef, capable of tracking a single proton. A BaF2 crystal measuring the residual energy of protons was used. Proton radiographs of phantom consisting of different tissue-like materials were measured with a 30×30 mm2 150 MeV proton beam. Measurements were simulated with the Geant4 toolkit.First experimental and simulated energy radiographs are in very good agreement [3]. In this paper we focus on simulation studies of the proton scattering angle as it affects the position resolution of the proton energy loss radiograph. By selecting protons with a small scattering angle, the image quality can be improved significantly.

  18. The clinical case for proton beam therapy

    Directory of Open Access Journals (Sweden)

    Foote Robert L

    2012-10-01

    Full Text Available Abstract Over the past 20 years, several proton beam treatment programs have been implemented throughout the United States. Increasingly, the number of new programs under development is growing. Proton beam therapy has the potential for improving tumor control and survival through dose escalation. It also has potential for reducing harm to normal organs through dose reduction. However, proton beam therapy is more costly than conventional x-ray therapy. This increased cost may be offset by improved function, improved quality of life, and reduced costs related to treating the late effects of therapy. Clinical research opportunities are abundant to determine which patients will gain the most benefit from proton beam therapy. We review the clinical case for proton beam therapy. Summary sentence Proton beam therapy is a technically advanced and promising form of radiation therapy.

  19. Principles and practice of proton beam therapy

    CERN Document Server

    Das, Indra J

    2015-01-01

    Commissioned by The American Association of Physicists in Medicine (AAPM) for their June 2015 Summer School, this is the first AAPM monograph printed in full color. Proton therapy has been used in radiation therapy for over 70 years, but within the last decade its use in clinics has grown exponentially. This book fills in the proton therapy gap by focusing on the physics of proton therapy, including beam production, proton interactions, biology, dosimetry, treatment planning, quality assurance, commissioning, motion management, and uncertainties. Chapters are written by the world's leading medical physicists who work at the pioneering proton treatment centers around the globe. They share their understandings after years of experience treating thousands of patients. Case studies involving specific cancer treatments show that there is some art to proton therapy as well as state-of-the-art science. Even though the focus lies on proton therapy, the content provided is also valuable to heavy charged particle th...

  20. Proton radiography and tomography with application to proton therapy

    Science.gov (United States)

    Allinson, N M; Evans, P M

    2015-01-01

    Proton radiography and tomography have long promised benefit for proton therapy. Their first suggestion was in the early 1960s and the first published proton radiographs and CT images appeared in the late 1960s and 1970s, respectively. More than just providing anatomical images, proton transmission imaging provides the potential for the more accurate estimation of stopping-power ratio inside a patient and hence improved treatment planning and verification. With the recent explosion in growth of clinical proton therapy facilities, the time is perhaps ripe for the imaging modality to come to the fore. Yet many technical challenges remain to be solved before proton CT scanners become commonplace in the clinic. Research and development in this field is currently more active than at any time with several prototype designs emerging. This review introduces the principles of proton radiography and tomography, their historical developments, the raft of modern prototype systems and the primary design issues. PMID:26043157

  1. Proton beam therapy control system

    Science.gov (United States)

    Baumann, Michael A.; Beloussov, Alexandre V.; Bakir, Julide; Armon, Deganit; Olsen, Howard B.; Salem, Dana

    2010-09-21

    A tiered communications architecture for managing network traffic in a distributed system. Communication between client or control computers and a plurality of hardware devices is administered by agent and monitor devices whose activities are coordinated to reduce the number of open channels or sockets. The communications architecture also improves the transparency and scalability of the distributed system by reducing network mapping dependence. The architecture is desirably implemented in a proton beam therapy system to provide flexible security policies which improve patent safety and facilitate system maintenance and development.

  2. Proton beam therapy control system

    Science.gov (United States)

    Baumann, Michael A.; Beloussov, Alexandre V.; Bakir, Julide; Armon, Deganit; Olsen, Howard B.; Salem, Dana

    2008-07-08

    A tiered communications architecture for managing network traffic in a distributed system. Communication between client or control computers and a plurality of hardware devices is administered by agent and monitor devices whose activities are coordinated to reduce the number of open channels or sockets. The communications architecture also improves the transparency and scalability of the distributed system by reducing network mapping dependence. The architecture is desirably implemented in a proton beam therapy system to provide flexible security policies which improve patent safety and facilitate system maintenance and development.

  3. [Proton imaging applications for proton therapy: state of the art].

    Science.gov (United States)

    Amblard, R; Floquet, V; Angellier, G; Hannoun-Lévi, J M; Hérault, J

    2015-04-01

    Proton therapy allows a highly precise tumour volume irradiation with a low dose delivered to the healthy tissues. The steep dose gradients observed and the high treatment conformity require a precise knowledge of the proton range in matter and the target volume position relative to the beam. Thus, proton imaging allows an improvement of the treatment accuracy, and thereby, in treatment quality. Initially suggested in 1963, radiographic imaging with proton is still not used in clinical routine. The principal difficulty is the lack of spatial resolution, induced by the multiple Coulomb scattering of protons with nuclei. Moreover, its realization for all clinical locations requires relatively high energies that are previously not considered for clinical routine. Abandoned for some time in favor of X-ray technologies, research into new imaging methods using protons is back in the news because of the increase of proton radiation therapy centers in the world. This article exhibits a non-exhaustive state of the art in proton imaging. Copyright © 2015 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  4. Towards Proton Therapy and Radiography at FAIR

    Science.gov (United States)

    Prall, M.; Lang, P. M.; LaTessa, C.; Mariam, F.; Merrill, F.; Shestov, L.; Simoniello, P.; Varentsov, D.; Durante, M.

    2015-04-01

    Protons having energies in the GeV range have been proposed as an alternative to Bragg-peak hadron therapy. This strategy reduces lateral scattering and overcomes uncertainties of particle range and relative biological effectiveness. GeV protons could additionally be used for targeting in image guided stereotactic radiosurgery. We experimentally demonstrated the potential of GeV protons for imaging of biological samples using E=0.8 GeV protons and the pRad setup at Los Alamos National Laboratory (LANL). In this setup, a system of magnetic lenses creates a point-to-point mapping from object to detector. This mapping compensates image blur due to lateral scattering inside the imaged (biological) object. We produced 2-dim proton radiographs of biological samples, an anthropomorphic phantom and performed simple dosimetry. High resolution tomographic reconstructions were derived from the 2-dim proton radiographs. Our experiment was performed within the framework of the PANTERA (Proton Therapy and Radiography) project. In the future, the proton microscope PRIOR (Proton Microscope for FAIR) located in the FAIR facility (Darmstadt), will focus on optimizing the technique for imaging of lesions implanted in animals and couple the irradiation with standard radiotherapy.

  5. Proton beam therapy how protons are revolutionizing cancer treatment

    CERN Document Server

    Yajnik, Santosh

    2013-01-01

    Proton beam therapy is an emerging technology with promise of revolutionizing the treatment of cancer. While nearly half of all patients diagnosed with cancer in the US receive radiation therapy, the majority is delivered via electron accelerators, where photons are used to irradiate cancerous tissue. Because of the physical properties of photon beams, photons may deposit energy along their entire path length through the body. On the other hand, a proton beam directed at a tumor travels in a straight trajectory towards its target, gives off most of its energy at a defined depth called the Bragg peak, and then stops. While photons often deposit more energy within the healthy tissues of the body than within the cancer itself, protons can deposit most of their cancer-killing energy within the area of the tumor. As a result, in the properly selected patients, proton beam therapy has the ability to improve cure rates by increasing the dose delivered to the tumor and simultaneously reduce side-effects by decreasing...

  6. New Developments in Proton Therapy Systems

    Science.gov (United States)

    Charlie Ma, C.-M.

    2009-07-01

    Proton beams can provide better dose conformity to the treatment target compared to commonly used photon and electron beams allowing for dose escalation and/or hypofractionation to increase local tumor control, reduce normal tissue complications and/or treatment time/cost. This paper reviews three novel proton accelerator designs that aim at cost-effective solutions for widespread applications of advanced particle therapy. The basic concepts, the system designs and the potential clinical applications are discussed in detail for superconductor accelerators, dielectric wall accelerators and laser-particle accelerators.

  7. Fan-beam intensity modulated proton therapy

    Science.gov (United States)

    Hill, Patrick; Westerly, David; Mackie, Thomas

    2013-01-01

    Purpose: This paper presents a concept for a proton therapy system capable of delivering intensity modulated proton therapy using a fan beam of protons. This system would allow present and future gantry-based facilities to deliver state-of-the-art proton therapy with the greater normal tissue sparing made possible by intensity modulation techniques. Methods: A method for producing a divergent fan beam of protons using a pair of electromagnetic quadrupoles is described and particle transport through the quadrupole doublet is simulated using a commercially available software package. To manipulate the fan beam of protons, a modulation device is developed. This modulator inserts or retracts acrylic leaves of varying thickness from subsections of the fan beam. Each subsection, or beam channel, creates what effectively becomes a beam spot within the fan area. Each channel is able to provide 0–255 mm of range shift for its associated beam spot, or stop the beam and act as an intensity modulator. Results of particle transport simulations through the quadrupole system are incorporated into the MCNPX Monte Carlo transport code along with a model of the range and intensity modulation device. Several design parameters were investigated and optimized, culminating in the ability to create topotherapy treatment plans using distal-edge tracking on both phantom and patient datasets. Results: Beam transport calculations show that a pair of electromagnetic quadrupoles can be used to create a divergent fan beam of 200 MeV protons over a distance of 2.1 m. The quadrupole lengths were 30 and 48 cm, respectively, with transverse field gradients less than 20 T/m, which is within the range of water-cooled magnets for the quadrupole radii used. MCNPX simulations of topotherapy treatment plans suggest that, when using the distal edge tracking delivery method, many delivery angles are more important than insisting on narrow beam channel widths in order to obtain conformal target coverage

  8. Journal of Proton Therapy: Call for Papers

    Directory of Open Access Journals (Sweden)

    Journal of Proton Therapy

    2015-03-01

    Full Text Available Journal of Proton Therapy (JPT is an international open access, peer-reviewed journal, which publishes original research, technical reports, reviews, case reports, editorials, and other materials on proton therapy with focus on radiation oncology, medical physics, medical dosimetry, and radiation therapy.No article processing/submission feeNo publication feePeer-review completion within 3-6 weeksImmediate publication after the completion of final author proofreadDOI assignment for each published articleFree access to published articles for all readers without any access barriers or subscriptionThe views and opinions expressed in articles are those of the author/s and do not necessarily reflect the policies of the Journal of Proton Therapy.Authors are encouraged to submit articles for publication in the inaugural issue of the Journal of Proton Therapy by online or email to editor@protonjournal.comFor more information, please visit www. protonjournal.comwww. protonjournal.org **************************************Journal of Proton Therapy Welcomes Editorial Board Members Chee-Wai Cheng, PhD Dr. Cheng is the Director of Proton Medical Physics at the University Hospitals as well as Professor of Clinical Radiation Oncology at the Case Western Reserve University, Cleveland, Ohio, USA.Carlos Vargas, MDDr. Vargas is a Radiation Oncologist at the Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona. Luca Cozzi, PhD Dr. Cozzi is a Clinical Research Scientist at the Department of Radiotherapy and Radiosurgery at Humanitas Cancer Center, Milan, Italy.Ted Ling, MD Dr. Ling is a Resident Physician at the Department of Radiation Medicine, Loma Linda University Medical Center, Loma Linda, California, USA.Haibo Lin, PhD Dr. Lin is a Medical Physicist at the Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.Xiaodong Zhang, PhD Dr. Zhang is an Associate Professor at the Department of Radiation Physics

  9. High gradient linac for proton therapy

    Directory of Open Access Journals (Sweden)

    S. Benedetti

    2017-04-01

    Full Text Available Proposed for the first time almost 30 years ago, the research on radio frequency linacs for hadron therapy experienced a sparkling interest in the past decade. The different projects found a common ground on a relatively high rf operating frequency of 3 GHz, taking advantage of the availability of affordable and reliable commercial klystrons at this frequency. This article presents for the first time the design of a proton therapy linac, called TULIP all-linac, from the source up to 230 MeV. In the first part, we will review the rationale of linacs for hadron therapy. We then divided this paper in two main sections: first, we will discuss the rf design of the different accelerating structures that compose TULIP; second, we will present the beam dynamics design of the different linac sections.

  10. Proton minibeam radiation therapy: Experimental dosimetry evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Peucelle, C.; Martínez-Rovira, I.; Prezado, Y., E-mail: prezado@imnc.in2p3.fr [IMNC-UMR 8165, CNRS, Paris 7 and Paris 11 Universities, 15 rue Georges Clemenceau, Orsay Cedex 91406 (France); Nauraye, C.; Patriarca, A.; Hierso, E.; Fournier-Bidoz, N. [Institut Curie - Centre de Protonthérapie d’Orsay, Campus Universitaire, Bât. 101, Orsay 91898 (France)

    2015-12-15

    Purpose: Proton minibeam radiation therapy (pMBRT) is a new radiotherapy (RT) approach that allies the inherent physical advantages of protons with the normal tissue preservation observed when irradiated with submillimetric spatially fractionated beams. This dosimetry work aims at demonstrating the feasibility of the technical implementation of pMBRT. This has been performed at the Institut Curie - Proton Therapy Center in Orsay. Methods: Proton minibeams (400 and 700 μm-width) were generated by means of a brass multislit collimator. Center-to-center distances between consecutive beams of 3200 and 3500 μm, respectively, were employed. The (passive scattered) beam energy was 100 MeV corresponding to a range of 7.7 cm water equivalent. Absolute dosimetry was performed with a thimble ionization chamber (IBA CC13) in a water tank. Relative dosimetry was carried out irradiating radiochromic films interspersed in a IBA RW3 slab phantom. Depth dose curves and lateral profiles at different depths were evaluated. Peak-to-valley dose ratios (PVDR), beam widths, and output factors were also assessed as a function of depth. Results: A pattern of peaks and valleys was maintained in the transverse direction with PVDR values decreasing as a function of depth until 6.7 cm. From that depth, the transverse dose profiles became homogeneous due to multiple Coulomb scattering. Peak-to-valley dose ratio values extended from 8.2 ± 0.5 at the phantom surface to 1.08 ± 0.06 at the Bragg peak. This was the first time that dosimetry in such small proton field sizes was performed. Despite the challenge, a complete set of dosimetric data needed to guide the first biological experiments was achieved. Conclusions: pMBRT is a novel strategy in order to reduce the side effects of RT. This works provides the experimental proof of concept of this new RT method: clinical proton beams might allow depositing a (high) uniform dose in a brain tumor located in the center of the brain (7.5 cm depth

  11. From 2D to 3D: Proton Radiography and Proton CT in proton therapy: A simulation study

    NARCIS (Netherlands)

    Takatsu, J.; van der Graaf, E.R.; van Goethem, M.-J.; Brandenburg, S.; Biegun, Aleksandra

    2016-01-01

    (1) Purpose In order to reduce the uncertainty in translation of the X-ray Computed Tomography (CT) image into a map of proton stopping powers (3-4% and even up to 10% in regions containing bones [1-8]), proton radiography is being studied as an alternative imaging technique in proton therapy. We pe

  12. ATPF - a dedicated proton therapy facility

    Science.gov (United States)

    Fang, Shou-Xian; Guan, Xia-Ling; Tang, Jing-Yu; Chen, Yuan; Deng, Chang-Dong; Dong, Hai-Yi; Fu, Shi-Nian; Jiao, Yi; Shu, Hang; Ouyang, Hua-Fu; Qiu, Jing; Shi, Cai-Tu; Sun, Hong; Wei, Jie; Yang, Mei; Zhang, Jing

    2010-03-01

    A proton therapy facility based on a linac injector and a slow-cycling synchrotron is proposed. To obtain good treatments for different cancer types, both the spot scanning method and the double-scattering method are adopted in the facility, whereas the nozzles include both gantry and fixed beam types. The proton accelerator chain includes a synchrotron of 250 MeV in maximum energy, an injector of 7 MeV consisting of an RFQ and a DTL linac, with a repetition rate of 0.5 Hz. The slow extraction using the third-order resonance and together with the RFKO method is considered to be a good method to obtain a stable and more-or-less homogenous beam spill. To benefit the spot scanning method, the extraction energy can be as many as about 200 between 60 MeV and 230 MeV. A new method - the emittance balancing technique of using a solenoid or a quadrupole rotator is proposed to solve the problem of unequal emittance in the two transverse planes with a beam slowly extracted from a synchrotron. The facility has been designed to keep the potential to be upgraded to include the carbon therapy in the future.

  13. Principles and Reality of Proton Therapy Treatment Allocation

    Energy Technology Data Exchange (ETDEWEB)

    Bekelman, Justin E., E-mail: bekelman@uphs.upenn.edu [Department of Radiation Oncology, Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Department of Medical Ethics and Health Policy, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Asch, David A. [Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, Pennsylvania (United States); The Wharton School and Penn Medicine Center for Health Care Innovation, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Tochner, Zelig [Department of Radiation Oncology, Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Friedberg, Joseph [Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Vaughn, David J. [Division of Hematology/Oncology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Rash, Ellen [Department of Radiation Oncology, Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Raksowski, Kevin [Department of Internal Medicine, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania (United States); Hahn, Stephen M. [Department of Radiation Oncology, Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States)

    2014-07-01

    Purpose: To present the principles and rationale of the Proton Priority System (PROPS), a priority points framework that assigns higher scores to patients thought to more likely benefit from proton therapy, and the distribution of PROPS scores by patient characteristics Methods and Materials: We performed multivariable logistic regression to evaluate the association between PROPS scores and receipt of proton therapy, adjusted for insurance status, gender, race, geography, and the domains that inform the PROPS score. Results: Among 1529 adult patients considered for proton therapy prioritization during our Center's ramp-up phase of treatment availability, PROPS scores varied by age, diagnosis, site, and other PROPS domains. In adjusted analyses, receipt of proton therapy was lower for patients with non-Medicare relative to Medicare health insurance (commercial vs Medicare: adjusted odds ratio [OR] 0.47, 95% confidence interval [CI] 0.34-0.64; managed care vs Medicare: OR 0.40, 95% CI 0.28-0.56; Medicaid vs Medicare: OR 0.24, 95% CI 0.13-0.44). Proton Priority System score and age were not significantly associated with receipt of proton therapy. Conclusions: The Proton Priority System is a rationally designed and transparent system for allocation of proton therapy slots based on the best available evidence and expert opinion. Because the actual allocation of treatment slots depends mostly on insurance status, payers may consider incorporating PROPS, or its underlying principles, into proton therapy coverage policies.

  14. Proton beam therapy in Japan: current and future status.

    Science.gov (United States)

    Sakurai, Hideyuki; Ishikawa, Hitoshi; Okumura, Toshiyuki

    2016-10-01

    The number of patients treated by proton beam therapy in Japan since 2000 has increased; in 2016, 11 proton facilities were available to treat patients. Notably, proton beam therapy is very useful for pediatric cancer; since the pediatric radiation dose to normal tissues should be reduced as much as possible because of the effect of radiation on growth, intellectual development, endocrine organ function and secondary cancer development. Hepatocellular carcinoma is common in Asia, and most of the studies of proton beam therapy for liver cancer have been reported by Japanese investigators. Proton beam therapy is also a standard treatment for nasal and paranasal lesions and lesions at the base of the skull, because the radiation dose to critical organs such as the eyes, optic nerves and central nervous system can be reduced with proton beam therapy. For prostate cancer, comparative studies that address adverse effects, safety, patient quality of life and socioeconomic issues should be performed to determine the appropriate use of proton beam therapy for prostate cancer. Regarding new proton beam therapy applications, experience with proton beam therapy combined with chemotherapy is limited, although favorable outcomes have been recently reported for locally advanced lung cancer, esophageal cancer and pancreatic cancer. Therefore, 'chemoproton' therapy appears to be a very attractive field for further clinical investigations. In conclusion, there are cost issues and considerations regarding national insurance for the use of proton beam therapy in Japan. Further studies and discussions are needed to address the use of proton beam therapy for several types of cancers, and for maintaining the quality of life of patients while retaining a high cure rate.

  15. Upgrading prostate cancer following proton beam therapy

    Directory of Open Access Journals (Sweden)

    Jennifer K Logan

    2015-01-01

    Full Text Available Pre- and post-radiation therapy (RT effects on prostate histology have not been rigorously studied, but there appears to be a correlation between escalating radiation dosage and increasing post-RT histologic changes. Despite this dose-response relationship, radiation-induced changes may be heterogenous among different patients and even within a single tumor. When assessing residual tumor it is important to understand biopsy evaluation in the post-RT setting. We present the case of a poorly differentiated prostate adenocarcinoma following proton beam RT in a 45-year-old man with pre-RT Gleason 4 + 3 = 7 disease diagnosed in the setting of an elevated serum prostate-specific antigen level.

  16. Upgrading prostate cancer following proton beam therapy.

    Science.gov (United States)

    Logan, Jennifer K; Rais-Bahrami, Soroush; Merino, Maria J; Pinto, Peter A

    2015-01-01

    Pre- and post-radiation therapy (RT) effects on prostate histology have not been rigorously studied, but there appears to be a correlation between escalating radiation dosage and increasing post-RT histologic changes. Despite this dose-response relationship, radiation-induced changes may be heterogenous among different patients and even within a single tumor. When assessing residual tumor it is important to understand biopsy evaluation in the post-RT setting. We present the case of a poorly differentiated prostate adenocarcinoma following proton beam RT in a 45-year-old man with pre-RT Gleason 4 + 3 = 7 disease diagnosed in the setting of an elevated serum prostate-specific antigen level.

  17. Insurance coverage decisions for pediatric proton therapy.

    Science.gov (United States)

    Ojerholm, Eric; Hill-Kayser, Christine E

    2017-08-07

    Proton beam therapy (PBT) holds promise for pediatric patients, but level 1 evidence is not available. In this context, we examined insurance coverage decisions at our facility from 2010 to 2015. PBT was initially denied for 11% of pediatric cases. However, nearly all denials were overturned on appeal-a process that often delayed care by more than a week. Despite unfavorable language in coverage policies, real-world decisions were eventual approval in >99% of cases. Payers appear to have largely accepted the current level-of-evidence for pediatric PBT, but all parties spend significant time and resources on appeals. Streamlined approval processes could align incentives among stakeholders. © 2017 Wiley Periodicals, Inc.

  18. Acromegaly said to respond to proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, C.A.

    1988-02-12

    A news article is presented which discusses a new use for proton therapy. As physicians and physicists continue to refine the clinical applications for charged particles, they can point to at least one notable success story: the treatment of acromegaly, a disorder that afflicts an estimated 250 persons in the United States each year. Bernard Kliman, MD, reported at the annual Endocrine Society meeting in Indianapolis that his group at Harvard Medical School, Boston, and the Harvard cyclotron has cured 479 (85.5%) of 560 patients with acromegaly or gigantism. Cure is defined as reducing growth hormone level to less than 5 ..mu..g/L and shrinking the soft tissue growth characteristic of the disease.

  19. Risk-optimized proton therapy to minimize radiogenic second cancers

    DEFF Research Database (Denmark)

    Rechner, Laura A; Eley, John G; Howell, Rebecca M

    2015-01-01

    Proton therapy confers substantially lower predicted risk of second cancer compared with photon therapy. However, no previous studies have used an algorithmic approach to optimize beam angle or fluence-modulation for proton therapy to minimize those risks. The objectives of this study were...... to demonstrate the feasibility of risk-optimized proton therapy and to determine the combination of beam angles and fluence weights that minimizes the risk of second cancer in the bladder and rectum for a prostate cancer patient. We used 6 risk models to predict excess relative risk of second cancer. Treatment...

  20. The M. D. Anderson proton therapy system.

    Science.gov (United States)

    Smith, Alfred; Gillin, Michael; Bues, Martin; Zhu, X Ronald; Suzuki, Kazumichi; Mohan, Radhe; Woo, Shiao; Lee, Andrew; Komaki, Ritsko; Cox, James; Hiramoto, Kazuo; Akiyama, Hiroshi; Ishida, Takayuki; Sasaki, Toshie; Matsuda, Koji

    2009-09-01

    The purpose of this study is to describe the University of Texas M. D. Anderson proton therapy system (PTC-H) including the accelerator, beam transport, and treatment delivery systems, the functionality and clinical parameters for passive scattering and pencil beam scanning treatment modes, and the results of acceptance tests. The PTC-H has a synchrotron (70-250 MeV) and four treatment rooms. An overall control system manages the treatment, physics, and service modes of operation. An independent safety system ensures the safety of patients, staff, and equipment. Three treatment rooms have isocentric gantries and one room has two fixed horizontal beamlines, which include a large-field treatment nozzle, used primarily for prostate treatments, and a small-field treatment nozzle for ocular treatments. Two gantry treatment rooms and the fixed-beam treatment room have passive scattering nozzles. The third gantry has a pencil beam scanning nozzle for the delivery of intensity modulated proton treatments (IMPT) and single field uniform dose (SFUD) treatments. The PTC-H also has an experimental room with a fixed horizontal beamline and a passive scattering nozzle. The equipment described above was provided by Hitachi, Ltd. Treatment planning is performed using the Eclipse system from Varian Medical Systems and data management is handled by the MOSAIQ system from IMPAC Medical Systems, Inc. The large-field passive scattering nozzles use double scattering systems in which the first scatterers are physically integrated with the range modulation wheels. The proton beam is gated on the rotating range modulation wheels at gating angles designed to produce spread-out-Bragg peaks ranging in size from 2 to 16 g/cm2. Field sizes of up to 25 x 25 cm2 can be achieved with the double scattering system. The IMPT delivery technique is discrete spot scanning, which has a maximum field size of 30 x 30 cm2. Depth scanning is achieved by changing the energy extracted from the synchrotron

  1. The M. D. Anderson proton therapy system

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Alfred; Gillin, Michael; Bues, Martin; Zhu, X. Ronald; Suzuki, Kazumichi; Mohan, Radhe; Woo, Shiao; Lee, Andrew; Komaki, Ritsko; Cox, James; Hiramoto, Kazuo; Akiyama, Hiroshi; Ishida, Takayuki; Sasaki, Toshie; Matsuda, Koji [Department of Radiation Oncology and Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston Texas 77030 (United States); Energy and Environmental Systems Laboratory, Hitachi, Ltd., 2-1, Omika-cho, Hitachi-shi, Ibaraki-ken 319-1221 (Japan); Hitachi Works, Hitachi, Ltd. Power Systems, 1-1, Saiwai-cho, 3-chome, Hitachi-shi, Ibaraki-ken 317-8511 (Japan)

    2009-09-15

    Purpose: The purpose of this study is to describe University of Texas M. D. Anderson proton therapy system (PTC-H) including the accelerator, beam transport, and treatment delivery systems, the functionality and clinical parameters for passive scattering and pencil beam scanning treatment modes, and the results of acceptance tests. Methods: The PTC-H has a synchrotron (70-250 MeV) and four treatment rooms. An overall control system manages the treatment, physics, and service modes of operation. An independent safety system ensures the safety of patients, staff, and equipment. Three treatment rooms have isocentric gantries and one room has two fixed horizontal beamlines, which include a large-field treatment nozzle, used primarily for prostate treatments, and a small-field treatment nozzle for ocular treatments. Two gantry treatment rooms and the fixed-beam treatment room have passive scattering nozzles. The third gantry has a pencil beam scanning nozzle for the delivery of intensity modulated proton treatments (IMPT) and single field uniform dose (SFUD) treatments. The PTC-H also has an experimental room with a fixed horizontal beamline and a passive scattering nozzle. The equipment described above was provided by Hitachi, Ltd. Treatment planning is performed using the Eclipse system from Varian Medical Systems and data management is handled by the MOSAIQ system from IMPAC Medical Systems, Inc. The large-field passive scattering nozzles use double scattering systems in which the first scatterers are physically integrated with the range modulation wheels. The proton beam is gated on the rotating range modulation wheels at gating angles designed to produce spread-out-Bragg peaks ranging in size from 2 to 16 g/cm{sup 2}. Field sizes of up to 25x25 cm{sup 2} can be achieved with the double scattering system. The IMPT delivery technique is discrete spot scanning, which has a maximum field size of 30x30 cm{sup 2}. Depth scanning is achieved by changing the energy

  2. Optimizing proton therapy at the LBL medical accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, J.

    1992-03-01

    This Grant has marked the beginning of a multi-year study process expected to lead to design and construction of at least one, possibly several hospital-based proton therapy facilities in the United States.

  3. Optimizing proton therapy at the LBL medical accelerator. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, J.

    1992-03-01

    This Grant has marked the beginning of a multi-year study process expected to lead to design and construction of at least one, possibly several hospital-based proton therapy facilities in the United States.

  4. Variable-Energy Cyclotron for Proton Therapy Application

    CERN Document Server

    Alenitsky, Yu G; Vorozhtsov, A S; Glazov, A A; Mytsyn, G V; Molokanov, A G; Onishchenko, L M

    2004-01-01

    The requirements to characteristics of the beams used for proton therapy are considered. The operation and proposed cyclotrons for proton therapy are briefly described. The technical decisions of creation of the cyclotron with energy variation in the range 70-230 MeV and with current up to 100 nA are estimated. Taking into account the fact, that the size and cost of the cyclotron are approximately determined by the maximum proton energy, it is realistically offered to limit the maximum proton energy to 190 MeV and to elaborate a cyclotron project with a warm winding of the magnet for acceleration of H^{-} ions. The energy of the extracted protons for each run is determined by a stripped target radius in the vacuum chamber of the accelerator, and the radiation dose field for the patient is created by the external devices using the developed techniques.

  5. Proton energy optimization and reduction for intensity-modulated proton therapy

    Science.gov (United States)

    Cao, Wenhua; Lim, Gino; Liao, Li; Li, Yupeng; Jiang, Shengpeng; Li, Xiaoqiang; Li, Heng; Suzuki, Kazumichi; Zhu, X. Ronald; Gomez, Daniel; Zhang, Xiaodong

    2014-10-01

    Intensity-modulated proton therapy (IMPT) is commonly delivered via the spot-scanning technique. To ‘scan’ the target volume, the proton beam is controlled by varying its energy to penetrate the patient’s body at different depths. Although scanning the proton beamlets or spots with the same energy can be as fast as 10-20 m s-1, changing from one proton energy to another requires approximately two additional seconds. The total IMPT delivery time thus depends mainly on the number of proton energies used in a treatment. Current treatment planning systems typically use all proton energies that are required for the proton beam to penetrate in a range from the distal edge to the proximal edge of the target. The optimal selection of proton energies has not been well studied. In this study, we sought to determine the feasibility of optimizing and reducing the number of proton energies in IMPT planning. We proposed an iterative mixed-integer programming optimization method to select a subset of all available proton energies while satisfying dosimetric criteria. We applied our proposed method to six patient datasets: four cases of prostate cancer, one case of lung cancer, and one case of mesothelioma. The numbers of energies were reduced by 14.3%-18.9% for the prostate cancer cases, 11.0% for the lung cancer cases and 26.5% for the mesothelioma case. The results indicate that the number of proton energies used in conventionally designed IMPT plans can be reduced without degrading dosimetric performance. The IMPT delivery efficiency could be improved by energy layer optimization leading to increased throughput for a busy proton center in which a delivery system with slow energy switch is employed.

  6. Proton Therapy Dose Characterization and Verification

    Science.gov (United States)

    2013-10-01

    shows a deviation in the polar WET plot at 15 degrees between the planning CT (green) and the corrected CBCT (blue) at the time of treatment...Pennsylvania is Figure 8. Detection of proton range differences between CBCT and planning CT images. The polar plot measures the water equivalent...dose wtrllin orout\\ide I’TVs was >114% of cl:te presclibed dose ( Fig. 1 D-G~ OVerall, procon p lans Tltft2 ilnd •d;.pdve pr-oton pla.n5 bdd

  7. Proton beam characterization in the experimental room of the Trento Proton Therapy facility

    Science.gov (United States)

    Tommasino, F.; Rovituso, M.; Fabiano, S.; Piffer, S.; Manea, C.; Lorentini, S.; Lanzone, S.; Wang, Z.; Pasini, M.; Burger, W. J.; La Tessa, C.; Scifoni, E.; Schwarz, M.; Durante, M.

    2017-10-01

    As proton therapy is becoming an established treatment methodology for cancer patients, the number of proton centres is gradually growing worldwide. The economical effort for building these facilities is motivated by the clinical aspects, but might be also supported by the potential relevance for the research community. Experiments with high-energy protons are needed not only for medical physics applications, but represent also an essential part of activities dedicated to detector development, space research, radiation hardness tests, as well as of fundamental research in nuclear and particle physics. Here we present the characterization of the beam line installed in the experimental room of the Trento Proton Therapy Centre (Italy). Measurements of beam spot size and envelope, range verification and proton flux were performed in the energy range between 70 and 228 MeV. Methods for reducing the proton flux from typical treatments values of 106-109 particles/s down to 101-105 particles/s were also investigated. These data confirm that a proton beam produced in a clinical centre build by a commercial company can be exploited for a broad spectrum of experimental activities. The results presented here will be used as a reference for future experiments.

  8. Proton-counting radiography for proton therapy: a proof of principle using CMOS APS technology.

    Science.gov (United States)

    Poludniowski, G; Allinson, N M; Anaxagoras, T; Esposito, M; Green, S; Manolopoulos, S; Nieto-Camero, J; Parker, D J; Price, T; Evans, P M

    2014-06-01

    Despite the early recognition of the potential of proton imaging to assist proton therapy (Cormack 1963 J. Appl. Phys. 34 2722), the modality is still removed from clinical practice, with various approaches in development. For proton-counting radiography applications such as computed tomography (CT), the water-equivalent-path-length that each proton has travelled through an imaged object must be inferred. Typically, scintillator-based technology has been used in various energy/range telescope designs. Here we propose a very different alternative of using radiation-hard CMOS active pixel sensor technology. The ability of such a sensor to resolve the passage of individual protons in a therapy beam has not been previously shown. Here, such capability is demonstrated using a 36 MeV cyclotron beam (University of Birmingham Cyclotron, Birmingham, UK) and a 200 MeV clinical radiotherapy beam (iThemba LABS, Cape Town, SA). The feasibility of tracking individual protons through multiple CMOS layers is also demonstrated using a two-layer stack of sensors. The chief advantages of this solution are the spatial discrimination of events intrinsic to pixelated sensors, combined with the potential provision of information on both the range and residual energy of a proton. The challenges in developing a practical system are discussed.

  9. Gantry optimization of the Shanghai Advanced Proton Therapy facility

    Institute of Scientific and Technical Information of China (English)

    吴军; 杜涵文; 薛; 潘家珍; 杜月斐; 龙亚文

    2015-01-01

    A proton therapy system is a large medical device to treat tumors. Its gantry is of large structure and high precision. A new half-gantry was designed in the Shanghai Advanced Proton Therapy (SAPT) project. In this paper, the weight of gantry in design is reduced significantly by size and structure optimizations, to improve its cost-effectiveness, while guaranteeing the functions and precision. The processes of physics optimization, empirical design optimization, topological optimization and size optimization, together with factors of consid-eration, are described. The gantry weight is reduced by 30%, with the same precision.

  10. Analytic estimates of secondary neutron dose in proton therapy.

    Science.gov (United States)

    Anferov, V

    2010-12-21

    Proton beam losses in various components of a treatment nozzle generate secondary neutrons, which bring unwanted out of field dose during treatments. The purpose of this study was to develop an analytic method for estimating neutron dose to a distant organ at risk during proton therapy. Based on radiation shielding calculation methods proposed by Sullivan, we developed an analytical model for converting the proton beam losses in the nozzle components and in the treatment volume into the secondary neutron dose at a point of interest. Using the MCNPx Monte Carlo code, we benchmarked the neutron dose rates generated by the proton beam stopped at various media. The Monte Carlo calculations confirmed the validity of the analytical model for simple beam stop geometry. The analytical model was then applied to neutron dose equivalent measurements performed on double scattering and uniform scanning nozzles at the Midwest Proton Radiotherapy Institute (MPRI). Good agreement was obtained between the model predictions and the data measured at MPRI. This work provides a method for estimating analytically the neutron dose equivalent to a distant organ at risk. This method can be used as a tool for optimizing dose delivery techniques in proton therapy.

  11. The computer simulation of laser proton acceleration for hadron therapy

    Science.gov (United States)

    Lykov, Vladimir; Baydin, Grigory

    2008-11-01

    The ions acceleration by intensive ultra-short laser pulses has interest in views of them possible applications for proton radiography, production of medical isotopes and hadron therapy. The 3D relativistic PIC-code LegoLPI is developed at RFNC-VNIITF for modeling of intensive laser interaction with plasma. The LegoLPI-code simulations were carried out to find the optimal conditions for generation of proton beams with parameters necessary for hadrons therapy. The performed simulations show that optimal for it may be two-layer foil of aluminum and polyethylene with thickness 100 nm and 50 nm accordingly. The maximum efficiency of laser energy transformation into 200 MeV protons is achieved on irradiating these foils by 30 fs laser pulse with intensity about 2.10^22 W/cm^2. The conclusion is made that lasers with peak power about 0.5-1PW and average power 0.5-1 kW are needed for generation of proton beams with parameters necessary for proton therapy.

  12. Beam Phase Detection for Proton Therapy Accelerators

    CERN Document Server

    Aminov, Bachtior; Getta, Markus; Kolesov, Sergej; Pupeter, Nico; Stephani, Thomas; Timmer, J

    2005-01-01

    The industrial application of proton cyclotrons for medical applications has become one of the important contributions of accelerator physics during the last years. This paper describes an advanced vector demodulating technique used for non-destructive measurements of beam intensity and beam phase over 360°. A computer controlled I/Q-based phase detector with a very large dynamic range of 70 dB permits the monitoring of beam intensity, phase and eventually energy for wide range of beam currents down to -130 dBm. In order to avoid interference from the fundamental cyclotron frequency the phase detection is performed at the second harmonic frequency. A digital low pass filter with adjustable bandwidth and steepness is implemented to improve accuracy. With a sensitivity of the capacitive pickup in the beam line of 30 nV per nA of proton beam current at 250 MeV, accurate phase and intensity measurements can be performed with beam currents down to 3.3 nA.

  13. Development of Technology for Image-Guided Proton Therapy

    Science.gov (United States)

    2012-10-01

    Hypofractionation for Intermediate-Risk Adenocarcinoma of the Prostate Nine more are planned. We hope that because our trials will esse ntially be using the...Adenocarcinoma of the  Prostate    iii) A Feasibility Trial of Proton Radiation Therapy or Intensity Modulated Radiation Therapy Using Mild  Hypofractionation

  14. Proton Therapy Dose Characterization and Verification

    Science.gov (United States)

    2016-10-01

    mechanism of injury. Purpose: 1) To estimate the degree of cognitive loss following radiation therapy. 2) To determine if clinical variables (including...therapy. In the original statement of work first of five planned projects were identified, to be implemented on a yearly basis to pro- vide the most...Laterality Midline 3 1 Right 0 2 Left 1 1 Location* Base of Skull 4 1 Frontal Lobe 0 2 Temporal Lobe 0 1

  15. Improving proton therapy by metal-containing nanoparticles : nanoscale insights

    NARCIS (Netherlands)

    Schlathölter, Thomas; Eustache, Pierre; Porcel, Erika; Salado, Daniela; Stefancikova, Lenka; Tillement, Olivier; Lux, Francois; Mowat, Pierre; Biegun, Aleksandra; van Goethem, Marc-Jan; Remita, Hynd; Lacombe, Sandrine

    2016-01-01

    The use of nanoparticles to enhance the effect of radiation-based cancer treatments is a growing field of study and recently, even nanoparticle-induced improvement of proton therapy performance has been investigated. Aiming at a clinical implementation of this approach, it is essential to

  16. Improving proton therapy by metal-containing nanoparticles : nanoscale insights

    NARCIS (Netherlands)

    Schlathölter, Thomas; Eustache, Pierre; Porcel, Erika; Salado, Daniela; Stefancikova, Lenka; Tillement, Olivier; Lux, Francois; Mowat, Pierre; Biegun, Aleksandra; van Goethem, Marc-Jan; Remita, Hynd; Lacombe, Sandrine

    2016-01-01

    The use of nanoparticles to enhance the effect of radiation-based cancer treatments is a growing field of study and recently, even nanoparticle-induced improvement of proton therapy performance has been investigated. Aiming at a clinical implementation of this approach, it is essential to characteri

  17. Improving proton therapy by metal-containing nanoparticles : nanoscale insights

    NARCIS (Netherlands)

    Schlathölter, Thomas; Eustache, Pierre; Porcel, Erika; Salado, Daniela; Stefancikova, Lenka; Tillement, Olivier; Lux, Francois; Mowat, Pierre; Biegun, Aleksandra; van Goethem, Marc-Jan; Remita, Hynd; Lacombe, Sandrine

    2016-01-01

    The use of nanoparticles to enhance the effect of radiation-based cancer treatments is a growing field of study and recently, even nanoparticle-induced improvement of proton therapy performance has been investigated. Aiming at a clinical implementation of this approach, it is essential to characteri

  18. Improving proton therapy by metal-containing nanoparticles: nanoscale insights

    Science.gov (United States)

    Schlathölter, Thomas; Eustache, Pierre; Porcel, Erika; Salado, Daniela; Stefancikova, Lenka; Tillement, Olivier; Lux, Francois; Mowat, Pierre; Biegun, Aleksandra K; van Goethem, Marc-Jan; Remita, Hynd; Lacombe, Sandrine

    2016-01-01

    The use of nanoparticles to enhance the effect of radiation-based cancer treatments is a growing field of study and recently, even nanoparticle-induced improvement of proton therapy performance has been investigated. Aiming at a clinical implementation of this approach, it is essential to characterize the mechanisms underlying the synergistic effects of nanoparticles combined with proton irradiation. In this study, we investigated the effect of platinum- and gadolinium-based nanoparticles on the nanoscale damage induced by a proton beam of therapeutically relevant energy (150 MeV) using plasmid DNA molecular probe. Two conditions of irradiation (0.44 and 3.6 keV/μm) were considered to mimic the beam properties at the entrance and at the end of the proton track. We demonstrate that the two metal-containing nanoparticles amplify, in particular, the induction of nanosize damages (>2 nm) which are most lethal for cells. More importantly, this effect is even more pronounced at the end of the proton track. This work gives a new insight into the underlying mechanisms on the nanoscale and indicates that the addition of metal-based nanoparticles is a promising strategy not only to increase the cell killing action of fast protons, but also to improve tumor targeting. PMID:27143877

  19. Proton beam deflection in MRI fields: Implications for MRI-guided proton therapy.

    Science.gov (United States)

    Oborn, B M; Dowdell, S; Metcalfe, P E; Crozier, S; Mohan, R; Keall, P J

    2015-05-01

    This paper investigates, via magnetic modeling and Monte Carlo simulation, the ability to deliver proton beams to the treatment zone inside a split-bore MRI-guided proton therapy system. Field maps from a split-bore 1 T MRI-Linac system are used as input to geant4 Monte Carlo simulations which model the trajectory of proton beams during their paths to the isocenter of the treatment area. Both inline (along the MRI bore) and perpendicular (through the split-bore gap) orientations are simulated. Monoenergetic parallel and diverging beams of energy 90, 195, and 300 MeV starting from 1.5 and 5 m above isocenter are modeled. A phase space file detailing a 2D calibration pattern is used to set the particle starting positions, and their spatial location as they cross isocenter is recorded. No beam scattering, collimation, or modulation of the proton beams is modeled. In the inline orientation, the radial symmetry of the solenoidal style fringe field acts to rotate the protons around the beam's central axis. For protons starting at 1.5 m from isocenter, this rotation is 19° (90 MeV) and 9.8° (300 MeV). A minor focusing toward the beam's central axis is also seen, but only significant, i.e., 2 mm shift at 150 mm off-axis, for 90 MeV protons. For the perpendicular orientation, the main MRI field and near fringe field act as the strongest to deflect the protons in a consistent direction. When starting from 1.5 m above isocenter shifts of 135 mm (90 MeV) and 65 mm (300 MeV) were observed. Further to this, off-axis protons are slightly deflected toward or away from the central axis in the direction perpendicular to the main deflection direction. This leads to a distortion of the phase space pattern, not just a shift. This distortion increases from zero at the central axis to 10 mm (90 MeV) and 5 mm (300 MeV) for a proton 150 mm off-axis. In both orientations, there is a small but subtle difference in the deflection and distortion pattern between protons fired parallel to the

  20. Outcomes of Proton Therapy for the Treatment of Uveal Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Kamran, Sophia C. [Harvard Medical School, Boston, Massachusetts (United States); Collier, John M. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Lane, Anne Marie; Kim, Ivana [Retina Service, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts (United States); Niemierko, Andrzej [Division of Biostatistics, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Chen, Yen-Lin E.; MacDonald, Shannon M.; Munzenrider, John E. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Gragoudas, Evangelos [Retina Service, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts (United States); Shih, Helen A., E-mail: hshih@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-12-01

    Purpose/Objective(s): Radiation therapy can be used to treat uveal metastases with the goal of local control and improvement of quality of life. Proton therapy can be used to treat uveal tumors efficiently and with expectant minimization of normal tissue injury. Here, we report the use of proton beam therapy for the management of uveal metastases. Methods and Materials: A retrospective chart review was made of all patients with uveal metastases treated at our institution with proton therapy between June 2002 and June 2012. Patient and tumor characteristics, fractionation and dose schemes, local control, and toxicities are reported. Results: Ninety patients were identified. Of those, 13 were excluded because of missing information. We report on 77 patients with 99 affected eyes with available data. Patients were 68% female, and the most common primary tumor was breast carcinoma (49%). The median age at diagnosis of uveal metastasis was 57.9 years. Serous retinal detachment was seen in 38% of treated eyes. The median follow-up time was 7.7 months. The median dose delivered to either eye was 20 Gy(relative biological effectiveness [RBE]) in 2 fractions. Local control was 94%. The median survival after diagnosis of uveal metastases was 12.3 months (95% confidence interval, 7.7-16.8). Death in all cases was secondary to systemic disease. Radiation vasculopathy, measured decreased visual acuity, or both was observed in 50% of evaluable treated eyes. The actuarial rate of radiation vasculopathy, measured decreased visual acuity, or both was 46% at 6 months and 73% at 1 year. The 6 eyes with documented local failure were successfully salvaged with retreatment. Conclusions: Proton therapy is an effective and efficient means of treating uveal metastases. Acutely, the majority of patients experience minor adverse effects. For longer-term survivors, the risk of retinal injury with vision loss increases significantly over the first year.

  1. Studies of a proton phase beam monitor for range verification in proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Werner, T.; Golnik, C.; Enghardt, W.; Petzoldt, J.; Kormoll, T.; Pausch, G. [Technische Universitaet Dresden, OncoRay, PF 41, 01307 Dresden, (Germany); Straessner, A. [Technische Universitaet Dresden, Institute for Nuclear and Particle Physics, Zellescher Weg 19, 01069 Dresden, (Germany); Roemer, K.; Dreyer, A.; Hueso-Gonzalez, F.; Enghardt, W. [Helmholtz-Zentrum Dresden-Rossendorf, PF 510 119, 01314 Dresden, (Germany)

    2015-07-01

    A primary subject of the present research in particle therapy is to ensure the precise irradiation of the target volume. The prompt gamma timing (PGT) method provides one possibility for in vivo range verification during the irradiation of patients. Prompt gamma rays with high energies are emitted promptly due to nuclear reactions of protons with tissue. The arrival time of these gammas to the detector reflects the stopping process of the primary protons in tissue and are directly correlated to the range. Due to the time resolution of the detector and the proton bunch time spread, as well as drifts of the bunch phase with respect to the accelerator frequency, timing spectra are smeared out and compromise the accuracy of range information intended for future clinical applications. Nevertheless, counteracting this limitation and recovering range information from the PGT measured spectra, corrections using a phase beam monitor can be performed. A first prototype of phase beam monitor was tested at GSI Darmstadt, where measurements of the energy profile of the ion bunches were performed. At the ELBE accelerator Helmholtz-Zentrum Dresden-Rossendorf (HZDR), set up to provide bremsstrahlung photons in very short pulses, a constant fraction algorithm for the incoming digital signals was evaluated, which is used for optimizing the time resolution. Studies of scattering experiments with different thin targets and detector positions are accomplished at Oncoray Dresden, where a clinical proton beam is available. These experiments allow a basic characterization of the proton bunch structure and the detection yield. (authors)

  2. Studies of a Proton Bunch Phase Monitor for Range Verification in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Werner, T.; Golnik, C.; Enghardt, W.; Petzoldt, J.; Kormoll, T.; Pausch, G. [Technische Universitaet Dresden, OncoRay, PF 41, 01307 Dresden (Germany); Straessner, A. [Technische Universitaet Dresden, Institute for Nuclear and Particle Physics, Zellescher Weg 19, 01069 Dresden (Germany); Roemer, K.; Dreyer, A.; Hueso-Gonzalez, F.; Enghardt, W. [Helmholtz-Zentrum Dresden-Rossendorf, PF 510 119, 01314 Dresden (Germany)

    2015-07-01

    A primary subject of the present research in particle therapy is to ensure the precise irradiation of the target volume. The prompt gamma timing (PGT) method provides one possibility for in vivo range verification during the irradiation of patients. Prompt gamma rays with high energies are emitted promptly due to nuclear reactions of protons with tissue. The arrival time of these gammas to the detector reflects the stopping process of the primary protons in tissue and is directly correlated to the range. Due to the time resolution of the detector and the proton bunch time spread, as well as drifts of the bunch phase with respect to the accelerator frequency, timing spectra are smeared out and compromise the accuracy of range information intended for future clinical applications. Nevertheless, counteracting this limitation and recovering range information from the PGT measured spectra, corrections using a bunch phase monitor can be performed. A first prototype of bunch phase monitor was tested at GSI Darmstadt, where measurements of the energy correlation profile of the ion bunches were performed. At the ELBE accelerator at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), set up to provide bremsstrahlung photons in very short pulses, a constant fraction algorithm for the incoming digital signals was evaluated, which is used for optimizing the time resolution. Studies of scattering experiments with different thin targets and detector positions are accomplished at Onco Ray Dresden, where a clinical proton beam is available. These experiments allow a basic characterization of the proton bunch structure and the detection yield. (authors)

  3. Shielding design for a laser-accelerated proton therapy system.

    Science.gov (United States)

    Fan, J; Luo, W; Fourkal, E; Lin, T; Li, J; Veltchev, I; Ma, C-M

    2007-07-07

    In this paper, we present the shielding analysis to determine the necessary neutron and photon shielding for a laser-accelerated proton therapy system. Laser-accelerated protons coming out of a solid high-density target have broad energy and angular spectra leading to dose distributions that cannot be directly used for therapeutic applications. A special particle selection and collimation device is needed to generate desired proton beams for energy- and intensity-modulated proton therapy. A great number of unwanted protons and even more electrons as a side-product of laser acceleration have to be stopped by collimation devices and shielding walls, posing a challenge in radiation shielding. Parameters of primary particles resulting from the laser-target interaction have been investigated by particle-in-cell simulations, which predicted energy spectra with 300 MeV maximum energy for protons and 270 MeV for electrons at a laser intensity of 2 x 10(21) W cm(-2). Monte Carlo simulations using FLUKA have been performed to design the collimators and shielding walls inside the treatment gantry, which consist of stainless steel, tungsten, polyethylene and lead. A composite primary collimator was designed to effectively reduce high-energy neutron production since their highly penetrating nature makes shielding very difficult. The necessary shielding for the treatment gantry was carefully studied to meet the criteria of head leakage shield neutrons and an outer layer of lead was used to reduce photon dose from neutron capture and electron bremsstrahlung. It is shown that the two-layer shielding design with 10-12 cm thick polyethylene and 4 cm thick lead can effectively absorb the unwanted particles to meet the shielding requirements.

  4. Shielding design for a laser-accelerated proton therapy system

    Science.gov (United States)

    Fan, J.; Luo, W.; Fourkal, E.; Lin, T.; Li, J.; Veltchev, I.; Ma, C.-M.

    2007-07-01

    In this paper, we present the shielding analysis to determine the necessary neutron and photon shielding for a laser-accelerated proton therapy system. Laser-accelerated protons coming out of a solid high-density target have broad energy and angular spectra leading to dose distributions that cannot be directly used for therapeutic applications. A special particle selection and collimation device is needed to generate desired proton beams for energy- and intensity-modulated proton therapy. A great number of unwanted protons and even more electrons as a side-product of laser acceleration have to be stopped by collimation devices and shielding walls, posing a challenge in radiation shielding. Parameters of primary particles resulting from the laser-target interaction have been investigated by particle-in-cell simulations, which predicted energy spectra with 300 MeV maximum energy for protons and 270 MeV for electrons at a laser intensity of 2 × 1021 W cm-2. Monte Carlo simulations using FLUKA have been performed to design the collimators and shielding walls inside the treatment gantry, which consist of stainless steel, tungsten, polyethylene and lead. A composite primary collimator was designed to effectively reduce high-energy neutron production since their highly penetrating nature makes shielding very difficult. The necessary shielding for the treatment gantry was carefully studied to meet the criteria of head leakage shield neutrons and an outer layer of lead was used to reduce photon dose from neutron capture and electron bremsstrahlung. It is shown that the two-layer shielding design with 10-12 cm thick polyethylene and 4 cm thick lead can effectively absorb the unwanted particles to meet the shielding requirements.

  5. Feasibility of using laser ion accelerators in proton therapy

    CERN Document Server

    Bulanov, S V

    2002-01-01

    The feasibility of using the laser plasma as a source of the high-energy ions for the proton radiation therapy is discussed. The proposal is based on the recent inventions of the effective ions acceleration in the experiments and through numerical modeling of the powerful laser radiation interaction with the gaseous and solid state targets. The principal peculiarity of the dependence of the protons energy losses in the tissues (the Bragg peak of losses) facilities the solution of one of the most important problems of the radiation therapy, which consists in realizing the tumor irradiation by sufficiently high and homogeneous dose with simultaneous minimization of the irradiation level, relative to the healthy and neighbouring tissues and organs

  6. Maximum proton kinetic energy and patient-generated neutron fluence considerations in proton beam arc delivery radiation therapy.

    Science.gov (United States)

    Sengbusch, E; Pérez-Andújar, A; DeLuca, P M; Mackie, T R

    2009-02-01

    Several compact proton accelerator systems for use in proton therapy have recently been proposed. Of paramount importance to the development of such an accelerator system is the maximum kinetic energy of protons, immediately prior to entry into the patient, that must be reached by the treatment system. The commonly used value for the maximum kinetic energy required for a medical proton accelerator is 250 MeV, but it has not been demonstrated that this energy is indeed necessary to treat all or most patients eligible for proton therapy. This article quantifies the maximum kinetic energy of protons, immediately prior to entry into the patient, necessary to treat a given percentage of patients with rotational proton therapy, and examines the impact of this energy threshold on the cost and feasibility of a compact, gantry-mounted proton accelerator treatment system. One hundred randomized treatment plans from patients treated with IMRT were analyzed. The maximum radiological pathlength from the surface of the patient to the distal edge of the treatment volume was obtained for 180 degrees continuous arc proton therapy and for 180 degrees split arc proton therapy (two 90 degrees arcs) using CT# profiles from the Pinnacle (Philips Medical Systems, Madison, WI) treatment planning system. In each case, the maximum kinetic energy of protons, immediately prior to entry into the patient, that would be necessary to treat the patient was calculated using proton range tables for various media. In addition, Monte Carlo simulations were performed to quantify neutron production in a water phantom representing a patient as a function of the maximum proton kinetic energy achievable by a proton treatment system. Protons with a kinetic energy of 240 MeV, immediately prior to entry into the patient, were needed to treat 100% of patients in this study. However, it was shown that 90% of patients could be treated at 198 MeV, and 95% of patients could be treated at 207 MeV. Decreasing the

  7. Hospital-based proton linear accelerator for particle therapy and radioisotope production

    Science.gov (United States)

    Lennox, Arlene J.

    1991-05-01

    Taking advantage of recent advances in linear accelerator technology, it is possible for a hospital to use a 70 MeV proton linac for fast neutron therapy, boron neutron capture therapy, proton therapy for ocular melanomas, and production of radiopharmaceuticals. The linac can also inject protons into a synchrotron for proton therapy of deep-seated tumors. With 180 μA average current, a single linac can support all these applications. This paper presents a conceptual design for a medical proton linac, switchyard, treatment rooms, and isotope production rooms. Special requirements for each application are outlined and a layout for sharing beam among the applications is suggested.

  8. Proton therapy for prostate cancer online: patient education or marketing?

    Science.gov (United States)

    Sadowski, Daniel J; Ellimoottil, Chandy S; Tejwani, Ajay; Gorbonos, Alex

    2013-12-01

    Proton therapy (PT) for prostate cancer is an expensive treatment with limited evidence of benefit over conventional radiotherapy. We sought to study whether online information on PT for prostate cancer was balanced and whether the website source influenced the content presented. We applied a systematic search process to identify 270 weblinks associated with PT for prostate cancer, categorized the websites by source, and filtered the results to 50 websites using predetermined criteria. We then used a customized version of the DISCERN instrument, a validated tool for assessing the quality of consumer health information, to evaluate the remaining websites for balance of content and description of risks, benefits and uncertainty. Depending on the search engine and key word used, proton center websites (PCWs) made up 10%-47% of the first 30 encountered links. In comparison, websites from academic and nonacademic medical centers without ownership stake in proton centers appeared much less frequently as a search result (0%-3%). PCWs scored lower on DISCERN questions compared to other sources for being balanced/unbiased (p marketing by proton centers rather than comprehensive and unbiased patient education. An awareness of these results will also better prepare clinicians to address the potential biases of patients with prostate cancer who search the Internet for health information.

  9. Monitoring proton radiation therapy with in-room PET imaging.

    Science.gov (United States)

    Zhu, Xuping; España, Samuel; Daartz, Juliane; Liebsch, Norbert; Ouyang, Jinsong; Paganetti, Harald; Bortfeld, Thomas R; El Fakhri, Georges

    2011-07-07

    We used a mobile positron emission tomography (PET) scanner positioned within the proton therapy treatment room to study the feasibility of proton range verification with an in-room, stand-alone PET system, and compared with off-line equivalent studies. Two subjects with adenoid cystic carcinoma were enrolled into a pilot study in which in-room PET scans were acquired in list-mode after a routine fractionated treatment session. The list-mode PET data were reconstructed with different time schemes to generate in-room short, in-room long and off-line equivalent (by skipping coincidences from the first 15 min during the list-mode reconstruction) PET images for comparison in activity distribution patterns. A phantom study was followed to evaluate the accuracy of range verification for different reconstruction time schemes quantitatively. The in-room PET has a higher sensitivity compared to the off-line modality so that the PET acquisition time can be greatly reduced from 30 to proton therapy. Better accuracy in Monte Carlo predictions, especially for biological decay modeling, is necessary.

  10. Magnetically scanned proton therapy beams: rationales and principles

    Science.gov (United States)

    Jones, D. T. L.; Schreuder, A. N.

    2001-06-01

    High-energy proton therapy is finding increased application in radiation oncology because of the unique physical characteristics of proton beams which allow superior conformation of the high-dose region to the target volume. The standard method of "painting" the required dose over the target volume is to use passive mechanical means involving multiple scattering and variable thickness absorbers. However, this technique dose not allow proximal surface dose conformation which can only be achieved using beam scanning techniques. Apart from reducing the integral dose, intensity modulation and inverse planning are possible, there is less activation of the surroundings and no field-specific modification devices are required. However, scanning systems are very complicated and there are very high instantaneous dose rates which require sophisticated control systems.

  11. Pitfalls of tungsten multileaf collimator in proton beam therapy

    Energy Technology Data Exchange (ETDEWEB)

    Moskvin, Vadim; Cheng, Chee-Wai; Das, Indra J. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana 46202 (United States) and Indiana University Health Proton Therapy Center (Formerly Midwest Proton Radiotherapy Institute), Bloomington, Indiana 47408 (United States)

    2011-12-15

    Purpose: Particle beam therapy is associated with significant startup and operational cost. Multileaf collimator (MLC) provides an attractive option to improve the efficiency and reduce the treatment cost. A direct transfer of the MLC technology from external beam radiation therapy is intuitively straightforward to proton therapy. However, activation, neutron production, and the associated secondary cancer risk in proton beam should be an important consideration which is evaluated. Methods: Monte Carlo simulation with FLUKA particle transport code was applied in this study for a number of treatment models. The authors have performed a detailed study of the neutron generation, ambient dose equivalent [H*(10)], and activation of a typical tungsten MLC and compared with those obtained from a brass aperture used in a typical proton therapy system. Brass aperture and tungsten MLC were modeled by absorber blocks in this study, representing worst-case scenario of a fully closed collimator. Results: With a tungsten MLC, the secondary neutron dose to the patient is at least 1.5 times higher than that from a brass aperture. The H*(10) from a tungsten MLC at 10 cm downstream is about 22.3 mSv/Gy delivered to water phantom by noncollimated 200 MeV beam of 20 cm diameter compared to 14 mSv/Gy for the brass aperture. For a 30-fraction treatment course, the activity per unit volume in brass aperture reaches 5.3 x 10{sup 4} Bq cm{sup -3} at the end of the last treatment. The activity in brass decreases by a factor of 380 after 24 h, additional 6.2 times after 40 days of cooling, and is reduced to background level after 1 yr. Initial activity in tungsten after 30 days of treating 30 patients per day is about 3.4 times higher than in brass that decreases only by a factor of 2 after 40 days and accumulates to 1.2 x 10{sup 6} Bq cm{sup -3} after a full year of operation. The daily utilization of the MLC leads to buildup of activity with time. The overall activity continues to increase

  12. Outcomes of Proton Therapy for Patients With Functional Pituitary Adenomas

    Energy Technology Data Exchange (ETDEWEB)

    Wattson, Daniel A.; Tanguturi, Shyam K. [Harvard Radiation Oncology Program, Boston, Massachusetts (United States); Spiegel, Daphna Y. [Tufts University School of Medicine, Boston, Massachusetts (United States); Niemierko, Andrzej [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Biller, Beverly M.K.; Nachtigall, Lisa B. [Neuroendocrine Unit, Massachusetts General Hospital, Boston, Massachusetts (United States); Bussière, Marc R. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Swearingen, Brooke; Chapman, Paul H. [Department of Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts (United States); Loeffler, Jay S. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Shih, Helen A., E-mail: hshih@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-11-01

    Purpose/Objective(s): This study evaluated the efficacy and toxicity of proton therapy for functional pituitary adenomas (FPAs). Methods and Materials: We analyzed 165 patients with FPAs who were treated at a single institution with proton therapy between 1992 and 2012 and had at least 6 months of follow-up. All but 3 patients underwent prior resection, and 14 received prior photon irradiation. Proton stereotactic radiosurgery was used for 92% of patients, with a median dose of 20 Gy(RBE). The remainder received fractionated stereotactic proton therapy. Time to biochemical complete response (CR, defined as ≥3 months of normal laboratory values with no medical treatment), local control, and adverse effects are reported. Results: With a median follow-up time of 4.3 years (range, 0.5-20.6 years) for 144 evaluable patients, the actuarial 3-year CR rate and the median time to CR were 54% and 32 months among 74 patients with Cushing disease (CD), 63% and 27 months among 8 patients with Nelson syndrome (NS), 26% and 62 months among 50 patients with acromegaly, and 22% and 60 months among 9 patients with prolactinomas, respectively. One of 3 patients with thyroid stimulating hormone—secreting tumors achieved CR. Actuarial time to CR was significantly shorter for corticotroph FPAs (CD/NS) compared with other subtypes (P=.001). At a median imaging follow-up time of 43 months, tumor control was 98% among 140 patients. The actuarial 3-year and 5-year rates of development of new hypopituitarism were 45% and 62%, and the median time to deficiency was 40 months. Larger radiosurgery target volume as a continuous variable was a significant predictor of hypopituitarism (adjusted hazard ratio 1.3, P=.004). Four patients had new-onset postradiosurgery seizures suspected to be related to generously defined target volumes. There were no radiation-induced tumors. Conclusions: Proton irradiation is an effective treatment for FPAs, and hypopituitarism remains the primary

  13. Mapping {sup 15}O Production Rate for Proton Therapy Verification

    Energy Technology Data Exchange (ETDEWEB)

    Grogg, Kira; Alpert, Nathaniel M.; Zhu, Xuping [Center for Advanced Radiological Sciences, Nuclear Medicine and Molecular Imaging, Radiology Department, Massachusetts General Hospital, Boston, Massachusetts (United States); Min, Chul Hee [Department of Radiological Science, College of Health Science, Yonsei University, Wonju, Kangwon (Korea, Republic of); Testa, Mauro; Winey, Brian [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Normandin, Marc D. [Center for Advanced Radiological Sciences, Nuclear Medicine and Molecular Imaging, Radiology Department, Massachusetts General Hospital, Boston, Massachusetts (United States); Shih, Helen A.; Paganetti, Harald; Bortfeld, Thomas [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); El Fakhri, Georges, E-mail: elfakhri@pet.mgh.harvard.edu [Center for Advanced Radiological Sciences, Nuclear Medicine and Molecular Imaging, Radiology Department, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2015-06-01

    Purpose: This work was a proof-of-principle study for the evaluation of oxygen-15 ({sup 15}O) production as an imaging target through the use of positron emission tomography (PET), to improve verification of proton treatment plans and to study the effects of perfusion. Methods and Materials: Dynamic PET measurements of irradiation-produced isotopes were made for a phantom and rabbit thigh muscles. The rabbit muscle was irradiated and imaged under both live and dead conditions. A differential equation was fitted to phantom and in vivo data, yielding estimates of {sup 15}O production and clearance rates, which were compared to live versus dead rates for the rabbit and to Monte Carlo predictions. Results: PET clearance rates agreed with decay constants of the dominant radionuclide species in 3 different phantom materials. In 2 oxygen-rich materials, the ratio of {sup 15}O production rates agreed with the expected ratio. In the dead rabbit thighs, the dynamic PET concentration histories were accurately described using {sup 15}O decay constant, whereas the live thigh activity decayed faster. Most importantly, the {sup 15}O production rates agreed within 2% (P>.5) between conditions. Conclusions: We developed a new method for quantitative measurement of {sup 15}O production and clearance rates in the period immediately following proton therapy. Measurements in the phantom and rabbits were well described in terms of {sup 15}O production and clearance rates, plus a correction for other isotopes. These proof-of-principle results support the feasibility of detailed verification of proton therapy treatment delivery. In addition, {sup 15}O clearance rates may be useful in monitoring permeability changes due to therapy.

  14. Spot-Scanning Proton Arc (SPArc) Therapy: The First Robust and Delivery-Efficient Spot-Scanning Proton Arc Therapy.

    Science.gov (United States)

    Ding, Xuanfeng; Li, Xiaoqiang; Zhang, J Michele; Kabolizadeh, Peyman; Stevens, Craig; Yan, Di

    2016-12-01

    To present a novel robust and delivery-efficient spot-scanning proton arc (SPArc) therapy technique. A SPArc optimization algorithm was developed that integrates control point resampling, energy layer redistribution, energy layer filtration, and energy layer resampling. The feasibility of such a technique was evaluated using sample patients: 1 patient with locally advanced head and neck oropharyngeal cancer with bilateral lymph node coverage, and 1 with a nonmobile lung cancer. Plan quality, robustness, and total estimated delivery time were compared with the robust optimized multifield step-and-shoot arc plan without SPArc optimization (Arcmulti-field) and the standard robust optimized intensity modulated proton therapy (IMPT) plan. Dose-volume histograms of target and organs at risk were analyzed, taking into account the setup and range uncertainties. Total delivery time was calculated on the basis of a 360° gantry room with 1 revolutions per minute gantry rotation speed, 2-millisecond spot switching time, 1-nA beam current, 0.01 minimum spot monitor unit, and energy layer switching time of 0.5 to 4 seconds. The SPArc plan showed potential dosimetric advantages for both clinical sample cases. Compared with IMPT, SPArc delivered 8% and 14% less integral dose for oropharyngeal and lung cancer cases, respectively. Furthermore, evaluating the lung cancer plan compared with IMPT, it was evident that the maximum skin dose, the mean lung dose, and the maximum dose to ribs were reduced by 60%, 15%, and 35%, respectively, whereas the conformity index was improved from 7.6 (IMPT) to 4.0 (SPArc). The total treatment delivery time for lung and oropharyngeal cancer patients was reduced by 55% to 60% and 56% to 67%, respectively, when compared with Arcmulti-field plans. The SPArc plan is the first robust and delivery-efficient proton spot-scanning arc therapy technique, which could potentially be implemented into routine clinical practice. Copyright © 2016 Elsevier Inc

  15. Proton-minibeam radiation therapy: A proof of concept

    Energy Technology Data Exchange (ETDEWEB)

    Prezado, Y. [IMNC-UMR 8165, CNRS, Paris 7 and Paris 11 Universities, 15 rue Georges Clemenceau, 91406 Orsay Cedex (France); Fois, G. R. [Dipartimento di Fisica, Universita degli Studi di Cagliari, Strada provinciale Monserrato Sestu km 0.700, Monserrato, Cagliari 09042 (Italy)

    2013-03-15

    Purpose: This Monte Carlo simulation work aims at studying a new radiotherapy approach called proton-minibeam radiation therapy (pMBRT). The main objective of this proof of concept was the evaluation of the possible gain in tissue sparing, thanks to the spatial fractionation of the dose, which could be used to deposit higher and potentially curative doses in clinical cases where tissue tolerances are a limit for conventional methods. Methods: Monte Carlo simulations (GATE v.6) have been used as a method to calculate the ratio of the peak-to-valley doses (PVDR) for arrays of proton minibeams of 0.7 mm width and several center-to-center distances, at different depths in a water phantom. The beam penumbras were also evaluated as an important parameter for tissue sparing, for example, in the treatment of non-cancer diseases like epilepsy. Two proton energies were considered in this study: a clinically relevant energy (105 MeV) and a very high energy (1 GeV), to benefit from a reduced lateral scattering. For the latter case, an interlaced geometry was also evaluated. Results: Higher or similar PVDR than the ones obtained in x-rays minibeam radiation therapy were achieved in several pMBRT configurations. In addition, for the two energies studied, the beam penumbras are smaller than in the case of Gamma Knife radiosurgery. Conclusions: The high PVDR obtained for some configurations and the small penumbras in comparison with existing radiosurgery techniques, suggest a potential gain in healthy tissue sparing in this new technique. Biological studies are warranted to assess the effects of pMBRT on both normal and tumoral tissues.

  16. SECONDARY NEUTRON DOSES IN A PROTON THERAPY CENTRE.

    Science.gov (United States)

    De Saint-Hubert, M; Saldarriaga Vargas, C; Van Hoey, O; Schoonjans, W; De Smet, V; Mathot, G; Stichelbaut, F; Manessi, G; Dinar, N; Aza, E; Cassell, C; Silari, M; Vanhavere, F

    2016-09-01

    The formation of secondary high-energy neutrons in proton therapy can be a concern for radiation protection of staff. In this joint intercomparative study (CERN, SCK•CEN and IBA/IRISIB/ULB), secondary neutron doses were assessed with different detectors in several positions in the Proton Therapy Centre, Essen (Germany). The ambient dose equivalent H(*)(10) was assessed with Berthold LB 6411, WENDI-2, tissue-equivalent proportional counter (TEPC) and Bonner spheres (BS). The personal dose equivalent Hp(10) was measured with two types of active detectors and with bubble detectors. Using spectral and basic angular information, the reference Hp(10) was estimated. Results concerning staff exposure show H(*)(10) doses between 0.5 and 1 nSv/monitoring unit in a technical room. The LB 6411 showed an underestimation of H(*)(10), while WENDI-2 and TEPC showed good agreement with the BS data. A large overestimation for Hp(10) was observed for the active personal dosemeters, while the bubble detectors showed only a slight overestimation.

  17. Capture and Transport of Laser Accelerated Protons by Pulsed Magnetic Fields: Advancements Toward Laser-Based Proton Therapy

    Science.gov (United States)

    Burris-Mog, Trevor J.

    The interaction of intense laser light (I > 10 18 W/cm2) with a thin target foil leads to the Target Normal Sheath Acceleration mechanism (TNSA). TNSA is responsible for the generation of high current, ultra-low emittance proton beams, which may allow for the development of a compact and cost effective proton therapy system for the treatment of cancer. Before this application can be realized, control is needed over the large divergence and the 100% kinetic energy spread that are characteristic of TNSA proton beams. The work presented here demonstrates control over the divergence and energy spread using strong magnetic fields generated by a pulse power solenoid. The solenoidal field results in a parallel proton beam with a kinetic energy spread DeltaE/E = 10%. Assuming that next generation lasers will be able to operate at 10 Hz, the 10% spread in the kinetic energy along with the 23% capture efficiency of the solenoid yield enough protons per laser pulse to, for the first time, consider applications in Radiation Oncology. Current lasers can generate proton beams with kinetic energies up to 67.5 MeV, but for therapy applications, the proton kinetic energy must reach 250 MeV. Since the maximum kinetic energy Emax of the proton scales with laser light intensity as Emax ∝ I0.5, next generation lasers may very well accelerate 250 MeV protons. As the kinetic energy of the protons is increased, the magnetic field strength of the solenoid will need to increase. The scaling of the magnetic field B with the kinetic energy of the protons follows B ∝ E1/2. Therefor, the field strength of the solenoid presented in this work will need to be increased by a factor of 2.4 in order to accommodate 250 MeV protons. This scaling factor seems reasonable, even with present technology. This work not only demonstrates control over beam divergence and energy spread, it also allows for us to now perform feasibility studies to further research what a laser-based proton therapy system

  18. Proton Therapy for Reirradiation of Progressive or Recurrent Chordoma

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Mark W., E-mail: mmcdona2@iuhealth.org [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana (United States); Indiana University Health Proton Therapy Center, Bloomington, Indiana (United States); Linton, Okechuckwu R. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana (United States); Shah, Mitesh V. [Department of Neurosurgery, Indiana University School of Medicine, Indianapolis, Indiana (United States)

    2013-12-01

    Purpose: To report the results in patients reirradiated with proton therapy for recurrent or progressive chordoma, with or without salvage surgery. Methods and Materials: A retrospective review of 16 consecutive patients treated from 2005 to 2012 was performed. All patients had received at least 1 prior course of radiation therapy to the same area, and all but 1 patient had at least 1 surgical resection for disease before receiving reirradiation. At the time of recurrence or progression, half of the patients underwent additional salvage surgery before receiving reirradiation. The median prior dose of radiation was 75.2 Gy (range, 40-79.2 Gy). Six patients had received prior proton therapy, and the remainder had received photon radiation. The median gross tumor volume at the time of reirradiation was 71 cm{sup 3} (range, 0-701 cm{sup 3}). Reirradiation occurred at a median interval of 37 months after prior radiation (range, 12-129 months), and the median dose of reirradiation was 75.6 Gy (relative biological effectiveness [RBE]) (range. 71.2-79.2 Gy [RBE]), given in standard daily fractionation (n=14) or hyperfractionation (n=2). Results: The median follow-up time was 23 months (range, 6-63 months); it was 26 months in patients alive at the last follow-up visit (range, 12-63 months). The 2-year estimate for local control was 85%, overall survival 80%, chordoma-specific survival 88%, and development of distant metastases 20%. Four patients have had local progression: 3 in-field and 1 marginal. Late toxicity included grade 3 bitemporal lobe radionecrosis in 1 patient that improved with hyperbaric oxygen, a grade 4 cerebrospinal fluid leak with meningitis in 1 patient, and a grade 4 ischemic brainstem stroke (out of radiation field) in 1 patient, with subsequent neurologic recovery. Conclusions: Full-dose proton reirradiation provided encouraging initial disease control and overall survival for patients with recurrent or progressive chordoma, although additional

  19. Verifying proton therapy irradiations with Time-Of-Flight positron emission tomography

    NARCIS (Netherlands)

    Oxley, D.; Biegun, A.; van der Borden, A.; Brandenburg, S.; Cambraia Lopes, P.; Diblen, F.; Vandenberghe, C.; Van't Velt, A.; Shaart, D.; Dendooven, Peter

    2012-01-01

    Compared to external beam photon therapy, proton therapy offers significant advantages in ensuring complete tumor destruction while minimizing collateral damage to healthy tissue. The reason for this is the highly localized dose deposition of ions (Bragg peak). However, dose delivery with protons (a

  20. Research advances in proton beam therapy for hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    DAI Shuyang

    2013-10-01

    Full Text Available Hepatocellular carcinoma (HCC, one of the most common malignancies with high prevalence and mortality rate, usually results in poor prognosis and limited survival. A comprehensive analysis on the number and location of tumors, Child-Pugh grade, and Barcelona Clinic Liver Cancer stage will help the development of suitable treatment programs and improve prediction of prognosis. A majority of patients are complicated by cirrhosis, enlarged tumor, multiple lesions, vascular invasion, and even cancer embolus in the portal vein. With the growth of knowledge about the radiation tolerance of normal tissue and the advances in radiotherapy techniques, radiotherapy has become an important tool for step-down therapy and adjuvant therapy for liver cancer. Proton beam therapy (PBT is emerging as a novel radiotherapy for the management of HCC, which, benefiting from the effect of Bragg Peak from PBT, effectively decreases the toxicity of traditional radiotherapies to the liver and does little harm to the uninvolved liver tissue or the surrounding structures while intensifying the destruction in targeted malignant lesions. Furthermore, several previous studies on the treatment of HCC with PBT revealed excellent local control. The distinctive biophysical attributes of PBT in the treatment of HCC, as well as the available literature regarding clinical outcomes and toxicity of using PBT for HCC, are reviewed. Current evidence provides limited indications for PBT, which suggests that further study on the relationship between liver function and PBT is required to gain further insight into its indication and standardization.

  1. Application of fluence field modulation to proton computed tomography for proton therapy imaging

    Science.gov (United States)

    Dedes, G.; De Angelis, L.; Rit, S.; Hansen, D.; Belka, C.; Bashkirov, V.; Johnson, R. P.; Coutrakon, G.; Schubert, K. E.; Schulte, R. W.; Parodi, K.; Landry, G.

    2017-08-01

    This simulation study presents the application of fluence field modulated computed tomography, initially developed for x-ray CT, to proton computed tomography (pCT). By using pencil beam (PB) scanning, fluence modulated pCT (FMpCT) may achieve variable image quality in a pCT image and imaging dose reduction. Three virtual phantoms, a uniform cylinder and two patients, were studied using Monte Carlo simulations of an ideal list-mode pCT scanner. Regions of interest (ROI) were selected for high image quality and only PBs intercepting them preserved full fluence (FF). Image quality was investigated in terms of accuracy (mean) and noise (standard deviation) of the reconstructed proton relative stopping power compared to reference values. Dose calculation accuracy on FMpCT images was evaluated in terms of dose volume histograms (DVH), range difference (RD) for beam-eye-view (BEV) dose profiles and gamma evaluation. Pseudo FMpCT scans were created from broad beam experimental data acquired with a list-mode pCT prototype. FMpCT noise in ROIs was equivalent to FF images and accuracy better than  -1.3%(-0.7%) by using 1% of FF for the cylinder (patients). Integral imaging dose reduction of 37% and 56% was achieved for the two patients for that level of modulation. Corresponding DVHs from proton dose calculation on FMpCT images agreed to those from reference images and 96% of BEV profiles had RD below 2 mm, compared to only 1% for uniform 1% of FF. Gamma pass rates (2%, 2 mm) were 98% for FMpCT while for uniform 1% of FF they were as low as 59%. Applying FMpCT to preliminary experimental data showed that low noise levels and accuracy could be preserved in a ROI, down to 30% modulation. We have shown, using both virtual and experimental pCT scans, that FMpCT is potentially feasible and may allow a means of imaging dose reduction for a pCT scanner operating in PB scanning mode. This may be of particular importance to proton therapy given the low integral dose found

  2. Dosimetric comparison of intensity modulated radiation, Proton beam therapy and proton arc therapy for para-aortic lymph node tumor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Hoon [Dept. of Radiation Oncology, Konyang University Hospital. Daejeon (Korea, Republic of)

    2014-12-15

    To test feasibility of proton arc therapy (PAT) in the treatment of para-aortic lymph node tumor and compare its dosimetric properties with advanced radiotherapy techniques such as intensity modulated radiation therapy (IMRT) and conventional 3D conformal proton beam therapy (PBT). The treatment plans for para-aortic lymph node tumor were planned for 9 patients treated at our institution using IMRT, PBT, and PAT. Feasibility test and dosimetric evaluation were based on comparisons of dose volume histograms (DVHs) which reveal mean dose, D{sub 30%}, D{sub 60%}, D{sub 90%}, V{sub 30%}, V{sub 60%}, V{sub 90}%, organ equivalent doses (OEDs), normal tissue complication probability (NTCP), homogeneity index (HI) and conformity index (CI). The average doses delivered by PAT to the liver, kidney, small bowel, duodenum, stomach were 7.6%, 3%, 17.3%, 26.7%, and 14.4%, of the prescription dose (PD), respectively, which is higher than the doses delivered by IMRT (0.4%, 7.2%, 14.2%, 15.9%, and 12.8%, respectively) and PBT (4.9%, 0.5%, 14.12%, 16.1% 9.9%, respectively). The average homogeneity index and conformity index of tumor using PAT were 12.1 and 1.21, respectively which were much better than IMRT (21.5 and 1.47, respectively) and comparable to PBT (13.1 and 1.23, respectively). The result shows that both NTCP and OED of PAT are generally lower than IMRT and PBT. This study demonstrates that PAT is better in target conformity and homogeneity than IMRT and PBT but worse than IMRT and PBT for most of dosimetric factor which indicate that PAT is not recommended for the treatment of para-aortic lymph node tumor.

  3. Proton therapy for tumors of the skull base

    Energy Technology Data Exchange (ETDEWEB)

    Munzenrider, J.E.; Liebsch, N.J. [Dept. of Radiation Oncology, Harvard Univ. Medical School, Boston, MA (United States)

    1999-06-01

    Charged particle beams are ideal for treating skull base and cervical spine tumors: dose can be focused in the target, while achieving significant sparing of the brain, brain stem, cervical cord, and optic nerves and chiasm. For skull base tumors, 10-year local control rates with combined proton-photon therapy are highest for chondrosarcomas, intermediate for male chordomas, and lowest for female chordomas (94%, 65%, and 42%, respectively). For cervical spine tumors, 10-year local control rates are not significantly different for chordomas and chondrosarcomas (54% and 48%, respectively), nor is there any difference in local control between males and females. Observed treatment-related morbidity has been judged acceptable, in view of the major morbidity and mortality which accompany uncontrolled tumor growth. (orig.)

  4. Conformal proton radiation therapy for pediatric low-grade astrocytomas

    Energy Technology Data Exchange (ETDEWEB)

    Hug, E.B. [Loma Linda Univ. Medical Center, Loma Linda, CA (United States). Dept. of Radiation Medicine; Loma Linda Univ. Medical Center, Loma Linda, CA (United States). Dept. of Pediatrics and Dept. of Pathology; Darthmouth-Hitchcock Medical Center, Lebanon, New Hampshire (United States). Section of Radiation Oncology; Muenter, M.W.; Archambeau, J.O.; DeVries, A.; Loredo, L.N.; Grove, R.I.; Slater, J.D. [Loma Linda Univ. Medical Center, Loma Linda, CA (United States). Dept. of Radiation Medicine; Liwnicz, B. [Loma Linda Univ. Medical Center, Loma Linda, CA (United States). Dept. of Pathology

    2002-01-01

    Background: To evaluate the safety and efficacy of proton radiation therapy (PRT) for intracranial low-grade astrocytomas, the authors analyzed the first 27 pediatric patients treated at Loma Linda University Medical Center (LLUMC). Patients and Method: Between September 1991 and August 1997, 27 patients (13 female, 14 male) underwent fractionated proton radiation therapy for progressive or recurrent low-grade astrocytoma. Age at time of treatment ranged from 2 to 18 years (mean: 8.7 years). Tumors were located centrally (diencephatic) in 15 patients, in the cerebral and cerebellar hemispheres in seven patients, and in the brainstem in five patients. 25/27 patients (92%) were treated for progressive, unresectable, or residual disease following subtotal resection. Tissue diagnosis was available in 23/27 patients (85%). Four patients with optic pathway tumors were treated without histologic confirmation. Target doses between 50.4 and 63.0 CGE (cobalt gray equivalent, mean: 55.2 CGE) were prescribed at 1.8 CGE per fraction, five treatments per week. Results: At a mean follow-up period of 3.3 years (0.6-6.8 years), 6/27 patients experienced local failure (all located within the irradiated field), and 4/27 patients had died. By anatomic site these data translated into rates of local control and survival of 87% (13/15 patients) and 93% (14/15 patients) for central tumors, 71% (5/7 patients) and 86% (6/7 patients) for hemispheric tumors, and 60% (3/5 patients) and 60% (3/5 patients) for tumors located in the brainstem. Proton radiation therapy was generally well tolerated. All children with local control maintained their performance status. One child with associated neurofibromatosis, Type 1, developed Moyamoya disease. All six patients with optic pathway tumors and useful vision maintained or improved their visual status. Conclusions: This report on pediatric low-grade astrocytomas confirms proton radiation therapy as a safe and efficacious 3-D conformal treatment

  5. Proton beam therapy for malignancy in Bloom syndrome.

    Science.gov (United States)

    Mizumoto, M; Hashii, H; Senarita, M; Sakai, S; Wada, T; Okumura, T; Tsuboi, K; Sakurai, H

    2013-04-01

    Bloom syndrome is a DNA repair disorder that is hypersensitive to radiotherapy. We describe the first case in which proton beam therapy (PBT) was used in a patient with Bloom syndrome to treat oropharyngeal cancer. The patient was a 32-year-old woman with Bloom syndrome who was diagnosed with oropharyngeal cancer staged as T2N2bM0 poorly differentiated squamous cell carcinoma. The primary tumor was located on the right tongue base and extended to the right lateral pharyngeal wall. Several right upper region lymph nodes were positive for metastases. We selected PBT in anticipation of dose reduction to normal tissue. The clinical target volume was defined as the area of the primary tumor and lymph node metastases plus an 8-mm margin. After treatment with 36 GyE (Gray equivalent) in 20 fractions (4-5 fractions per week), dietary intake was decreased by mucositis and intravenous hyperalimentation was started. Termination of treatment for 2.5 weeks was required to relieve mucositis. Administration of 59.4 GyE in 33 fractions markedly reduced the size of the primary tumor, but also caused moderate mucositis that required termination of PBT. One month later, lung metastases and breast cancer developed and the patient died 9 months after PBT. At this time the reduction in size of the primary tumor was maintained without severe late toxicity. We obtained almost complete response for a radiosensitive patient with a deficiency of DNA repair, indicating the excellent dose concentration of proton beam therapy.

  6. A virtual simulator designed for collision prevention in proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hyunuk [Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351 (Korea, Republic of); Kum, Oyeon [Heavy-Ion Medical Accelerator Development Center, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Han, Youngyih, E-mail: youngyih@skku.edu; Park, Hee Chul; Kim, Jin Sung; Choi, Doo Ho [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351 (Korea, Republic of)

    2015-10-15

    Purpose: In proton therapy, collisions between the patient and nozzle potentially occur because of the large nozzle structure and efforts to minimize the air gap. Thus, software was developed to predict such collisions between the nozzle and patient using treatment virtual simulation. Methods: Three-dimensional (3D) modeling of a gantry inner-floor, nozzle, and robotic-couch was performed using SolidWorks based on the manufacturer’s machine data. To obtain patient body information, a 3D-scanner was utilized right before CT scanning. Using the acquired images, a 3D-image of the patient’s body contour was reconstructed. The accuracy of the image was confirmed against the CT image of a humanoid phantom. The machine components and the virtual patient were combined on the treatment-room coordinate system, resulting in a virtual simulator. The simulator simulated the motion of its components such as rotation and translation of the gantry, nozzle, and couch in real scale. A collision, if any, was examined both in static and dynamic modes. The static mode assessed collisions only at fixed positions of the machine’s components, while the dynamic mode operated any time a component was in motion. A collision was identified if any voxels of two components, e.g., the nozzle and the patient or couch, overlapped when calculating volume locations. The event and collision point were visualized, and collision volumes were reported. Results: All components were successfully assembled, and the motions were accurately controlled. The 3D-shape of the phantom agreed with CT images within a deviation of 2 mm. Collision situations were simulated within minutes, and the results were displayed and reported. Conclusions: The developed software will be useful in improving patient safety and clinical efficiency of proton therapy.

  7. Clinical Implementation of Intensity Modulated Proton Therapy for Thoracic Malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Joe Y., E-mail: jychang@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Li, Heng; Zhu, X. Ronald [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao, Zhongxing; Zhao, Lina [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liu, Amy [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Li, Yupeng [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Applied Research, Varian Medical Systems, Palo Alto, California (United States); Sahoo, Narayan; Poenisch, Falk [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gomez, Daniel R. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wu, Richard; Gillin, Michael [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhang, Xiaodong, E-mail: xizhang@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2014-11-15

    Purpose: Intensity modulated proton therapy (IMPT) can improve dose conformality and better spare normal tissue over passive scattering techniques, but range uncertainties complicate its use, particularly for moving targets. We report our early experience with IMPT for thoracic malignancies in terms of motion analysis and management, plan optimization and robustness, and quality assurance. Methods and Materials: Thirty-four consecutive patients with lung/mediastinal cancers received IMPT to a median 66 Gy(relative biological equivalence [RBE]). All patients were able to undergo definitive radiation therapy. IMPT was used when the treating physician judged that IMPT conferred a dosimetric advantage; all patients had minimal tumor motion (<5 mm) and underwent individualized tumor-motion dose-uncertainty analysis and 4-dimensional (4D) computed tomographic (CT)-based treatment simulation and motion analysis. Plan robustness was optimized by using a worst-case scenario method. All patients had 4D CT repeated simulation during treatment. Results: IMPT produced lower mean lung dose (MLD), lung V{sub 5} and V{sub 20}, heart V{sub 40}, and esophageal V{sub 60} than did IMRT (P<.05) and lower MLD, lung V{sub 20}, and esophageal V{sub 60} than did passive scattering proton therapy (PSPT) (P<.05). D{sub 5} to the gross tumor volume and clinical target volume was higher with IMPT than with intensity modulated radiation therapy or PSPT (P<.05). All cases were analyzed for beam-angle-specific motion, water-equivalent thickness, and robustness. Beam angles were chosen to minimize the effect of respiratory motion and avoid previously treated regions, and the maximum deviation from the nominal dose-volume histogram values was kept at <5% for the target dose and met the normal tissue constraints under a worst-case scenario. Patient-specific quality assurance measurements showed that a median 99% (range, 95% to 100%) of the pixels met the 3% dose/3 mm distance criteria for the

  8. Proton Radiation Therapy for Head and Neck Cancer: A Review of the Clinical Experience to Date

    Energy Technology Data Exchange (ETDEWEB)

    Holliday, Emma B.; Frank, Steven J., E-mail: sjfrank@mdanderson.org

    2014-06-01

    Proton beam radiation has been used for cancer treatment since the 1950s, but recent increasing interest in this form of therapy and the construction of hospital-based and clinic-based facilities for its delivery have greatly increased both the number of patients and the variety of tumors being treated with proton therapy. The mass of proton particles and their unique physical properties (ie, the Bragg peak) allow proton therapy to spare normal tissues distal to the tumor target from incidental irradiation. Initial observations show that proton therapy is particularly useful for treating tumors in challenging locations close to nontarget critical structures. Specifically, improvements in local control outcomes for patients with chordoma, chonodrosarcoma, and tumors in the sinonasal regions have been reported in series using proton. Improved local control and survival outcomes for patients with cancer of the head and neck region have also been seen with the advent of improvements in better imaging and multimodality therapy comprising surgery, radiation therapy, and chemotherapy. However, aggressive local therapy in the proximity of critical normal structures to tumors in the head and neck region may produce debilitating early and late toxic effects. Great interest has been expressed in evaluating whether proton therapy can improve outcomes, especially early and late toxicity, when used in the treatment of head and neck malignancies. This review summarizes the progress made to date in addressing this question.

  9. Prioritized efficiency optimization for intensity modulated proton therapy

    Science.gov (United States)

    Müller, Birgit S.; Wilkens, Jan J.

    2016-12-01

    A high dosimetric quality and short treatment time are major goals in radiotherapy planning. Intensity modulated proton therapy (IMPT) plans obtain dose distributions of great conformity but often result in long delivery times which are typically not incorporated into the optimization process. We present an algorithm to optimize delivery efficiency of IMPT plans while maintaining plan quality, and study the potential trade-offs of these interdependent objectives. The algorithm is based on prioritized optimization, a stepwise approach to implemented objectives. First the quality of the plan is optimized. The second step of the prioritized efficiency optimization (PrEfOpt) routine offers four alternatives for reducing delivery time: minimization of the total spot weight sum (A), maximization of the lowest spot intensity of each energy layer (B), elimination of low-weighted spots (C) or energy layers (D). The trade-off between dosimetric quality (step I) and treatment time (step II) is controlled during the optimization by option-dependent parameters. PrEfOpt was applied to a clinical patient case, and plans for different trade-offs were calculated. Delivery times were simulated for two virtual facilities with constant and variable proton current, i.e. independent and dependent on the optimized spot weight distributions. Delivery times decreased without major degradation of plan quality; absolute time reductions varied with the applied method and facility type. Minimizing the total spot weight sum (A) reduced times by 28% for a similar plan quality at a constant current (changes of minimum dose in the target  process can yield reduced delivery times with similar plan qualities. A potential clinical application of PrEfOpt is the generation of multiple plans with different trade-offs for a multicriteria optimization setting. Then, the planner can select the preferred compromise between treatment time and quality for each individual patient.

  10. Monte Carlo calculations supporting patient plan verification in proton therapy

    Directory of Open Access Journals (Sweden)

    Thiago Viana Miranda Lima

    2016-03-01

    Full Text Available Patient’s treatment plan verification covers substantial amount of the quality assurance (QA resources, this is especially true for Intensity Modulated Proton Therapy (IMPT. The use of Monte Carlo (MC simulations in supporting QA has been widely discussed and several methods have been proposed. In this paper we studied an alternative approach from the one being currently applied clinically at Centro Nazionale di Adroterapia Oncologica (CNAO. We reanalysed the previously published data (Molinelli et al. 2013, where 9 patient plans were investigated in which the warning QA threshold of 3% mean dose deviation was crossed. The possibility that these differences between measurement and calculated dose were related to dose modelling (Treatment Planning Systems (TPS vs MC, limitations on dose delivery system or detectors mispositioning was originally explored but other factors such as the geometric description of the detectors were not ruled out. For the purpose of this work we compared ionisation-chambers measurements with different MC simulations results. It was also studied some physical effects introduced by this new approach for example inter detector interference and the delta ray thresholds. The simulations accounting for a detailed geometry typically are superior (statistical difference - p-value around 0.01 to most of the MC simulations used at CNAO (only inferior to the shift approach used. No real improvement were observed in reducing the current delta-ray threshold used (100 keV and no significant interference between ion chambers in the phantom were detected (p-value 0.81. In conclusion, it was observed that the detailed geometrical description improves the agreement between measurement and MC calculations in some cases. But in other cases position uncertainty represents the dominant uncertainty. The inter chamber disturbance was not detected for the therapeutic protons energies and the results from the current delta threshold are

  11. 160 MeV laser-accelerated protons from CH2 nano-targets for proton cancer therapy

    CERN Document Server

    Hegelich, B M; Albright, B J; Cheung, M; Dromey, B; Gautier, D C; Hamilton, C; Letzring, S; Munchhausen, R; Palaniyappan, S; Shah, R; Wu, H -C; Yin, L; Fernández, J C

    2013-01-01

    Proton (and ion) cancer therapy has proven to be an extremely effective even supe-rior method of treatment for some tumors 1-4. A major problem, however, lies in the cost of the particle accelerator facilities; high procurement costs severely limit the availability of ion radiation therapy, with only ~26 centers worldwide. Moreover, high operating costs often prevent economic operation without state subsidies and have led to a shutdown of existing facilities 5,6. Laser-accelerated proton and ion beams have long been thought of as a way out of this dilemma, with the potential to provide the required ion beams at lower cost and smaller facility footprint 7-14. The biggest challenge has been the achievement of sufficient particle energy for therapy, in the 150-250 MeV range for protons 15,16. For the last decade, the maximum exper-imentally observed energy of laser-accelerated protons has remained at ~60 MeV 17. Here we the experimental demonstration of laser-accelerated protons to energies exceeding 150 MeV, re...

  12. Treatment planning, optimization, and beam delivery technqiues for intensity modulated proton therapy

    Science.gov (United States)

    Sengbusch, Evan R.

    Physical properties of proton interactions in matter give them a theoretical advantage over photons in radiation therapy for cancer treatment, but they are seldom used relative to photons. The primary barriers to wider acceptance of proton therapy are the technical feasibility, size, and price of proton therapy systems. Several aspects of the proton therapy landscape are investigated, and new techniques for treatment planning, optimization, and beam delivery are presented. The results of these investigations suggest a means by which proton therapy can be delivered more efficiently, effectively, and to a much larger proportion of eligible patients. An analysis of the existing proton therapy market was performed. Personal interviews with over 30 radiation oncology leaders were conducted with regard to the current and future use of proton therapy. In addition, global proton therapy market projections are presented. The results of these investigations serve as motivation and guidance for the subsequent development of treatment system designs and treatment planning, optimization, and beam delivery methods. A major factor impacting the size and cost of proton treatment systems is the maximum energy of the accelerator. Historically, 250 MeV has been the accepted value, but there is minimal quantitative evidence in the literature that supports this standard. A retrospective study of 100 patients is presented that quantifies the maximum proton kinetic energy requirements for cancer treatment, and the impact of those results with regard to treatment system size, cost, and neutron production is discussed. This study is subsequently expanded to include 100 cranial stereotactic radiosurgery (SRS) patients, and the results are discussed in the context of a proposed dedicated proton SRS treatment system. Finally, novel proton therapy optimization and delivery techniques are presented. Algorithms are developed that optimize treatment plans over beam angle, spot size, spot spacing

  13. Application of proton boron fusion reaction to radiation therapy: A Monte Carlo simulation study

    Science.gov (United States)

    Yoon, Do-Kun; Jung, Joo-Young; Suh, Tae Suk

    2014-12-01

    Three alpha particles are emitted from the point of reaction between a proton and boron. The alpha particles are effective in inducing the death of a tumor cell. After boron is accumulated in the tumor region, the emitted from outside the body proton can react with the boron in the tumor region. An increase of the proton's maximum dose level is caused by the boron and only the tumor cell is damaged more critically. In addition, a prompt gamma ray is emitted from the proton boron reaction point. Here, we show that the effectiveness of the proton boron fusion therapy was verified using Monte Carlo simulations. We found that a dramatic increase by more than half of the proton's maximum dose level was induced by the boron in the tumor region. This increase occurred only when the proton's maximum dose point was located within the boron uptake region. In addition, the 719 keV prompt gamma ray peak produced by the proton boron fusion reaction was positively detected. This therapy method features the advantages such as the application of Bragg-peak to the therapy, the accurate targeting of tumor, improved therapy effects, and the monitoring of the therapy region during treatment.

  14. Shortening delivery times of intensity modulated proton therapy by reducing proton energy layers during treatment plan optimization

    NARCIS (Netherlands)

    S. van de Water (Steven); H.M. Kooy; B.J.M. Heijmen (Ben); M.S. Hoogeman (Mischa)

    2015-01-01

    textabstractPurpose To shorten delivery times of intensity modulated proton therapy by reducing the number of energy layers in the treatment plan. Methods and Materials We have developed an energy layer reduction method, which was implemented into our in-house-developed multicriteria treatment

  15. Shortening delivery times of intensity modulated proton therapy by reducing proton energy layers during treatment plan optimization

    NARCIS (Netherlands)

    S. van de Water (Steven); H.M. Kooy; B.J.M. Heijmen (Ben); M.S. Hoogeman (Mischa)

    2015-01-01

    textabstractPurpose To shorten delivery times of intensity modulated proton therapy by reducing the number of energy layers in the treatment plan. Methods and Materials We have developed an energy layer reduction method, which was implemented into our in-house-developed multicriteria treatment plann

  16. First tests for an online treatment monitoring system with in-beam PET for proton therapy

    CERN Document Server

    Kraan, Aafke C; Belcari, N; Camarlinghi, N; Cappucci, F; Ciocca, M; Ferrari, A; Ferretti, S; Mairani, A; Molinelli, S; Pullia, M; Retico, A; Sala, P; Sportelli, G; Del Guerra, A; Rosso, V

    2014-01-01

    PET imaging is a non-invasive technique for particle range verification in proton therapy. It is based on measuring the beta+ annihilations caused by nuclear interactions of the protons in the patient. In this work we present measurements for proton range verification in phantoms, performed at the CNAO particle therapy treatment center in Pavia, Italy, with our 10 x 10 cm^2 planar PET prototype DoPET. PMMA phantoms were irradiated with mono-energetic proton beams and clinical treatment plans, and PET data were acquired during and shortly after proton irradiation. We created 1-D profiles of the beta+ activity along the proton beam-axis, and evaluated the difference between the proximal rise and the distal fall-off position of the activity distribution. A good agreement with FLUKA Monte Carlo predictions was obtained. We also assessed the system response when the PMMA phantom contained an air cavity. The system was able to detect these cavities quickly after irradiation.

  17. First tests for an online treatment monitoring system with in-beam PET for proton therapy

    Science.gov (United States)

    Kraan, A. C.; Battistoni, G.; Belcari, N.; Camarlinghi, N.; Cappucci, F.; Ciocca, M.; Ferrari, A.; Ferretti, S.; Mairani, A.; Molinelli, S.; Pullia, M.; Retico, A.; Sala, P.; Sportelli, G.; Del Guerra, A.; Rosso, V.

    2015-01-01

    PET imaging is a non-invasive technique for particle range verification in proton therapy. It is based on measuring the β+ annihilations caused by nuclear interactions of the protons in the patient. In this work we present measurements for proton range verification in phantoms, performed at the CNAO particle therapy treatment center in Pavia, Italy, with our 10 × 10 cm2 planar PET prototype DoPET. PMMA phantoms were irradiated with mono-energetic proton beams and clinical treatment plans, and PET data were acquired during and shortly after proton irradiation. We created 1-D profiles of the β+ activity along the proton beam-axis, and evaluated the difference between the proximal rise and the distal fall-off position of the activity distribution. A good agreement with FLUKA Monte Carlo predictions was obtained. We also assessed the system response when the PMMA phantom contained an air cavity. The system was able to detect these cavities quickly after irradiation.

  18. The first private-hospital based proton therapy center in Korea; status of the Proton Therapy Center at Samsung Medical Center

    OpenAIRE

    Chung, Kwangzoo; Han, Youngyih; Kim, Jinsung; Ahn, Sung Hwan; Ju, Sang Gyu; Jung, Sang Hoon; Chung, Yoonsun; Cho, Sungkoo; Jo, Kwanghyun; Shin, Eun Hyuk; Hong, Chae-Seon; Shin, Jung Suk; Park, Seyjoon; Kim, Dae-Hyun; Kim, Hye Young

    2015-01-01

    Purpose The purpose of this report is to describe the proton therapy system at Samsung Medical Center (SMC-PTS) including the proton beam generator, irradiation system, patient positioning system, patient position verification system, respiratory gating system, and operating and safety control system, and review the current status of the SMC-PTS. Materials and Methods The SMC-PTS has a cyclotron (230 MeV) and two treatment rooms: one treatment room is equipped with a multi-purpose nozzle and ...

  19. Proton therapy of cancer: Potential clinical advantages and cost-effectiveness

    Energy Technology Data Exchange (ETDEWEB)

    Lundkvist, Jonas; Ekman, Mattias [Stockholm Health Economics, Stockholm (Sweden); Rehn Ericsson, Suzanne [Univ. Hospital, Uppsala (Sweden). Dept. of Oncology, Radiology and Clinical Immunology; Joensson, Bengt [Stockholm School of Economics, Stockholm (Sweden); Glimelius, Bengt [Karolinska Inst., Stockholm (Sweden). Dept. of Oncology and Pathology; Akademiska sjukhuset, Uppsala (Sweden). Dept. of Oncology, Radiology and Clinical Immunology

    2005-12-01

    Proton therapy may offer potential clinical advantages compared with conventional radiation therapy for many cancer patients. Due to the large investment costs for building a proton therapy facility, however, the treatment cost with proton radiation is higher than with conventional radiation. It is therefore important to evaluate whether the medical benefits of proton therapy are large enough to motivate the higher costs. We assessed the cost-effectiveness of proton therapy in the treatment of four different cancers: left-sided breast cancer, prostate cancer, head and neck cancer, and childhood medulloblastoma. A Markov cohort simulation model was created for each cancer type and used to simulate the life of patients treated with radiation. Cost and quality adjusted life years (QALYs) were used as primary outcome measures. The results indicated that proton therapy was cost-effective if appropriate risk groups were chosen. The average cost per QALY gained for the four types of cancer assessed was about Euro 10,130. If the value of a QALY was set to Euro 55,000, the total yearly net benefit of treating 925 cancer patients with the four types of cancer was about Euro 20.8 million. Investment in a proton facility may thus be cost-effective. The results must be interpreted with caution, since there is a lack of data, and consequently large uncertainties in the assumptions used.

  20. Calculation of energy deposition, photon and neutron production in proton therapy of thyroid gland using MCNPX.

    Science.gov (United States)

    Mowlavi, Ali Asghar; Fornasie, Maria Rosa; de Denaro, Mario

    2011-01-01

    In this study, the MCNPX code has been used to simulate a proton therapy in thyroid gland, in order to calculate the proton energy deposition in the target region. As well as, we have calculated the photon and neutron production spectra due to proton interactions with the tissue. We have considered all the layers of tissue, from the skin to the thyroid gland, and an incident high energy pencil proton beam. The results of the simulation show that the best proton energy interval, to cover completely the thyroid tissue, is from 42 to 54 MeV, assuming that the thyroid gland has a 14 mm thickness and is located 11.2mm under the skin surface. The most percentage of deposited energy (78%) is related to the 54 MeV proton energy beam. Total photon and neutron production are linear and polynomial second order functions of the proton energy, respectively.

  1. Beam tests on a proton linac booster for hadron therapy

    CERN Document Server

    De Martinis, C; Berra, P; Birattari, C; Calabretta, L; Crandall, K; Giove, D; Masullo, M R; Mauri, M; Rosso, E; Rovelli, A; Serafini, L; Szeless, Balázs; Toet, D Z; Vaccaro, Vittorio G; Weiss, M; Zennaro, R

    2002-01-01

    LIBO is a 3 GHz modular side-coupled proton linac booster designed to deliver beam energies up to 200 MeV, as required for the therapy of deep seated tumours. The injected beam of 50 to 70 MeV is produced by a cyclotron like those in several hospitals and research institutes. A full-scale prototype of the first module with an input/output energy of 62/74 MeV, respectively, was designed and built in 1999 and 2000. Full power RF tests were carried out successfully at CERN using a test facility at LIL at the end of the year 2000. In order to prove the feasibility of the acceleration process, an experimental setup with this module was installed at the INFN Laboratorio Nazionale del Sud (LNS) in Catania during 2001. The superconducting cyclotron provided the 62 MeV test beam. A compact solid-state RF modulator with a 4 MW klystron, made available by IBA-Scanditronix, was put into operation to power the linac. In this paper the main features of the accelerator are reviewed and the experimental results obtained duri...

  2. SU-E-T-649: Quality Assurances for Proton Therapy Delivery Equipment

    Energy Technology Data Exchange (ETDEWEB)

    Arjomandy, B; Kase, Y; Flanz, J; Yorke, E; Followill, D [McLaren Cancer Institute, Flint, MI (United States); Klein, E [Washington University, Saint Louis, MO (United States); Taylor, P [UT MD Anderson Cancer Center, Houston, TX (United States); Ainsley, C [University of Pennsylvania, Philadelphia, PA (United States); Safai, S [Paul Scherrer Institute, Villigen - Psi (Switzerland); Sahoo, N [MD Anderson Cancer Center, Houston, TX (United States); Pankuch, M [CDH Proton Center, Warrenville, IL (United States); Park, S [McLaren-Flint, Flint, MI (United States); Farr, J [St. Jude Children’s Research Hospital, Memphis, TN (United States)

    2015-06-15

    Purpose: The number of proton therapy centers has increased dramatically over the past decade. Currently, there is no comprehensive set of guidelines that addresses quality assurance (QA) procedures for the different technologies used for proton therapy. The AAPM has charged task group 224 (TG-224) to provide recommendations for QA required for accurate and safe dose delivery, using existing and next generation proton therapy delivery equipment. Methods: A database comprised of QA procedures and tolerance limits was generated from many existing proton therapy centers in and outside of the US. These consist of proton therapy centers that possessed double scattering, uniform scanning, and pencil beams delivery systems. The diversity in beam delivery systems as well as the existing devices to perform QA checks for different beam parameters is the main subject of TG-224. Based on current practice at the clinically active proton centers participating in this task group, consensus QA recommendations were developed. The methodologies and requirements of the parameters that must be verified for consistency of the performance of the proton beam delivery systems are discussed. Results: TG-224 provides procedures and QA checks for mechanical, imaging, safety and dosimetry requirements for different proton equipment. These procedures are categorized based on their importance and their required frequencies in order to deliver a safe and consistent dose. The task group provides daily, weekly, monthly, and annual QA check procedures with their tolerance limits. Conclusions: The procedures outlined in this protocol provide sufficient information to qualified medical physicists to perform QA checks for any proton delivery system. Execution of these procedures should provide confidence that proton therapy equipment is functioning as commissioned for patient treatment and delivers dose safely and accurately within the established tolerance limits. The report will be published in late

  3. Patient-specific stopping power calibration for proton therapy planning based on single-detector proton radiography.

    Science.gov (United States)

    Doolan, P J; Testa, M; Sharp, G; Bentefour, E H; Royle, G; Lu, H-M

    2015-03-07

    A simple robust optimizer has been developed that can produce patient-specific calibration curves to convert x-ray computed tomography (CT) numbers to relative stopping powers (HU-RSPs) for proton therapy treatment planning. The difference between a digitally reconstructed radiograph water-equivalent path length (DRRWEPL) map through the x-ray CT dataset and a proton radiograph (set as the ground truth) is minimized by optimizing the HU-RSP calibration curve. The function of the optimizer is validated with synthetic datasets that contain no noise and its robustness is shown against CT noise. Application of the procedure is then demonstrated on a plastic and a real tissue phantom, with proton radiographs produced using a single detector. The mean errors using generic/optimized calibration curves between the DRRWEPL map and the proton radiograph were 1.8/0.4% for a plastic phantom and -2.1/ - 0.2% for a real tissue phantom. It was then demonstrated that these optimized calibration curves offer a better prediction of the water equivalent path length at a therapeutic depth. We believe that these promising results are suggestive that a single proton radiograph could be used to generate a patient-specific calibration curve as part of the current proton treatment planning workflow.

  4. CPO-IPN collaboration for proton therapy; La collaboration CPO-IPN pour la protontherapy

    Energy Technology Data Exchange (ETDEWEB)

    Arianer, J.; Buhour, J.M.; Coat, F.; Mueller, A.C. [Services Techniques, Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France); Mazal, A. [CPO, Paris-11 Univ., 91 - Orsay (France)

    1999-11-01

    Since January 1997 a collaboration between CPO-IPN has been started in order to develop proton therapy instruments at Orsay. The final purposes are to build an isocentric gantry and further a medically dedicated super-conducting proton accelerator for treatment of cancers. (authors) 6 figs., 1 tab.

  5. Proton Beam Therapy and Concurrent Chemotherapy for Esophageal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Steven H., E-mail: shlin@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Komaki, Ritsuko; Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wei, Caimiao [Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Myles, Bevan [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Guo Xiaomao [Department of Radiation Oncology, Fudan University Cancer Hospital, Shanghai (China); Palmer, Matthew [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe [Department of Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Swisher, Stephen G.; Hofstetter, Wayne L. [Department of Thoracic and Cardiovascular Surgery, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Ajani, Jaffer A. [Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Cox, James D. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2012-07-01

    Purpose: Proton beam therapy (PBT) is a promising modality for the management of thoracic malignancies. We report our preliminary experience of treating esophageal cancer patients with concurrent chemotherapy (CChT) and PBT (CChT/PBT) at MD Anderson Cancer Center. Methods and Materials: This is an analysis of 62 esophageal cancer patients enrolled on a prospective study evaluating normal tissue toxicity from CChT/PBT from 2006 to 2010. Patients were treated with passive scattering PBT with two- or three-field beam arrangement using 180 to 250 MV protons. We used the Kaplan-Meier method to assess time-to-event outcomes and compared the distributions between groups using the log-rank test. Results: The median follow-up time was 20.1 months for survivors. The median age was 68 years (range, 38-86). Most patients were males (82%) who had adenocarcinomas (76%) and Stage II-III disease (84%). The median radiation dose was 50.4 Gy (RBE [relative biologic equivalence]) (range, 36-57.6). The most common grade 2 to 3 acute toxicities from CChT/PBT were esophagitis (46.8%), fatigue (43.6%), nausea (33.9%), anorexia (30.1%), and radiation dermatitis (16.1%). There were two cases of grade 2 and 3 radiation pneumonitis and two cases of grade 5 toxicities. A total of 29 patients (46.8%) received preoperative CChT/PBT, with one postoperative death. The pathologic complete response (pCR) rate for the surgical cohort was 28%, and the pCR and near CR rates (0%-1% residual cells) were 50%. While there were significantly fewer local-regional recurrences in the preoperative group (3/29) than in the definitive CChT/PBT group (16/33) (log-rank test, p = 0.005), there were no differences in distant metastatic (DM)-free interval or overall survival (OS) between the two groups. Conclusions: This is the first report of patients treated with PBT/CChT for esophageal cancer. Our data suggest that this modality is associated with a few severe toxicities, but the pathologic response and clinical

  6. COMPACT PROTON INJECTOR AND FIRST ACCELERATOR SYSTEM TEST FOR COMPACT PROTON DIELECTRIC WALL CANCER THERAPY ACCELERATOR

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y; Guethlein, G; Caporaso, G; Sampayan, S; Blackfield, D; Cook, E; Falabella, S; Harris, J; Hawkins, S; Nelson, S; Poole, B; Richardson, R; Watson, J; Weir, J; Pearson, D

    2009-04-23

    A compact proton accelerator for cancer treatment is being developed by using the high-gradient dielectric insulator wall (DWA) technology [1-4]. We are testing all the essential DWA components, including a compact proton source, on the First Article System Test (FAST). The configuration and progress on the injector and FAST will be presented.

  7. SU-E-J-201: Investigation of MRI Guided Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Li, JS [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2015-06-15

    Purpose: Image-guided radiation therapy has been employed for cancer treatment to improve the tumor localization accuracy. Radiation therapy with proton beams requires more on this accuracy because the proton beam has larger uncertainty and dramatic dose variation along the beam direction. Among all the image modalities, magnetic-resonance image (MRI) is the best for soft tissue delineation and real time motion monitoring. In this work, we investigated the behavior of the proton beam in magnetic field with Monte Carlo simulations. Methods: A proton Monte Carlo platform, TOPAS, was used for this investigation. Dose calculations were performed with this platform in a 30cmx30cmx30cm water phantom for both pencil and broad proton beams with different energies (120, 150 and 180MeV) in different magnetic fields (0.5T, 1T and 3T). The isodose distributions, dose profiles in lateral and beam direction were evaluated. The shifts of the Bragg peak in different magnetic fields for different proton energies were compared and the magnetic field effects on the characters of the dose distribution were analyzed. Results: Significant effects of magnetic field have been observed on the proton beam dose distributions, especially for magnetic field of 1T and up. The effects are more significant for higher energy proton beam because higher energy protons travel longer distance in the magnetic field. The Bragg peak shift in the lateral direction is about 38mm for 180MeV and 11mm for 120MeV proton beams in 3T magnetic field. The peak positions are retracted back for 6mm and 2mm, respectively. The effect on the beam penumbra and dose falloff at the distal edge of the Bragg peak is negligible. Conclusion: Though significant magnetic effects on dose distribution have been observed for proton beams, MRI guided proton therapy is feasible because the magnetic effects on dose is predictable and can be considered in patient dose calculation.

  8. Outcomes of treatment with stereotactic radiosurgery or proton beam therapy for choroidal melanoma.

    Science.gov (United States)

    Sikuade, M J; Salvi, S; Rundle, P A; Errington, D G; Kacperek, A; Rennie, I G

    2015-09-01

    To present our experience of the use of stereotactic radiosurgery and proton beam therapy to treat posterior uveal melanoma over a 10 year period. Case notes of patients treated with stereotactic radiosurgery (SRS), or Proton beam therapy (PBT) for posterior uveal melanoma were reviewed. Data collected included visual acuity at presentation and final review, local control rates, globe retention and complications. We analysed post-operative visual outcomes and if visual outcomes varied with proximity to the optic nerve or fovea. 191 patients were included in the study; 85 and 106 patients received Stereotactic radiosurgery and Proton beam therapy, respectively. Mean follow up period was 39 months in the SRS group and 34 months in the PBT group. Both treatments achieved excellent local control rates with eye retention in 98% of the SRS group and 95% in the PBT group. The stereotactic radiosurgery group showed a poorer visual prognosis with 65% losing more than 3 lines of Snellen acuity compared to 45% in the PBT group. 33% of the SRS group and 54% of proton beam patients had a visual acuity of 6/60 or better. Stereotactic radiosurgery and proton beam therapy are effective treatments for larger choroidal melanomas or tumours unsuitable for plaque radiotherapy. Our results suggest that patients treated with proton beam therapy retain better vision post-operatively; however, possible confounding factors include age, tumour location and systemic co-morbidities. These factors as well as the patient's preference should be considered when deciding between these two therapies.

  9. Proton Radiation Therapy for the Treatment of Retinoblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Mouw, Kent W. [Harvard Radiation Oncology Program, Boston, Massachusetts (United States); Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Sethi, Roshan V.; Yeap, Beow Y.; MacDonald, Shannon M.; Chen, Yen-Lin E.; Tarbell, Nancy J.; Yock, Torunn I.; Munzenrider, John E.; Adams, Judith [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Grabowski, Eric [Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts (United States); Mukai, Shizuo [Retina Service, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts (United States); Shih, Helen A., E-mail: hshih@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-11-15

    Purpose: To investigate long-term disease and toxicity outcomes for pediatric retinoblastoma patients treated with proton radiation therapy (PRT). Methods and Materials: This is a retrospective analysis of 49 retinoblastoma patients (60 eyes) treated with PRT between 1986 and 2012. Results: The majority (84%) of patients had bilateral disease, and nearly half (45%) had received prior chemotherapy. At a median follow-up of 8 years (range, 1-24 years), no patients died of retinoblastoma or developed metastatic disease. The post-PRT enucleation rate was low (18%), especially in patients with early-stage disease (11% for patients with International Classification for Intraocular Retinoblastoma [ICIR] stage A-B disease vs 23% for patients with ICIR stage C-D disease). Post-PRT ophthalmologic follow-up was available for 61% of the preserved eyes (30 of 49): 14 of 30 eyes (47%) had 20/40 visual acuity or better, 7 of 30 (23%) had moderate visual acuity (20/40-20/600), and 9 of 30 (30%) had little or no useful vision (worse than 20/600). Twelve of 60 treated eyes (20%) experienced a post-PRT event requiring intervention, with cataracts the most common (4 eyes). No patients developed an in-field second malignancy. Conclusions: Long-term follow-up of retinoblastoma patients treated with PRT demonstrates that PRT can achieve high local control rates, even in advanced cases, and many patients retain useful vision in the treated eye. Treatment-related ocular side effects were uncommon, and no radiation-associated malignancies were observed.

  10. The first private-hospital based proton therapy center in Korea; status of the Proton Therapy Center at Samsung Medical Center.

    Science.gov (United States)

    Chung, Kwangzoo; Han, Youngyih; Kim, Jinsung; Ahn, Sung Hwan; Ju, Sang Gyu; Jung, Sang Hoon; Chung, Yoonsun; Cho, Sungkoo; Jo, Kwanghyun; Shin, Eun Hyuk; Hong, Chae-Seon; Shin, Jung Suk; Park, Seyjoon; Kim, Dae-Hyun; Kim, Hye Young; Lee, Boram; Shibagaki, Gantaro; Nonaka, Hideki; Sasai, Kenzo; Koyabu, Yukio; Choi, Changhoon; Huh, Seung Jae; Ahn, Yong Chan; Pyo, Hong Ryull; Lim, Do Hoon; Park, Hee Chul; Park, Won; Oh, Dong Ryul; Noh, Jae Myung; Yu, Jeong Il; Song, Sanghyuk; Lee, Ji Eun; Lee, Bomi; Choi, Doo Ho

    2015-12-01

    The purpose of this report is to describe the proton therapy system at Samsung Medical Center (SMC-PTS) including the proton beam generator, irradiation system, patient positioning system, patient position verification system, respiratory gating system, and operating and safety control system, and review the current status of the SMC-PTS. The SMC-PTS has a cyclotron (230 MeV) and two treatment rooms: one treatment room is equipped with a multi-purpose nozzle and the other treatment room is equipped with a dedicated pencil beam scanning nozzle. The proton beam generator including the cyclotron and the energy selection system can lower the energy of protons down to 70 MeV from the maximum 230 MeV. The multi-purpose nozzle can deliver both wobbling proton beam and active scanning proton beam, and a multi-leaf collimator has been installed in the downstream of the nozzle. The dedicated scanning nozzle can deliver active scanning proton beam with a helium gas filled pipe minimizing unnecessary interactions with the air in the beam path. The equipment was provided by Sumitomo Heavy Industries Ltd., RayStation from RaySearch Laboratories AB is the selected treatment planning system, and data management will be handled by the MOSAIQ system from Elekta AB. The SMC-PTS located in Seoul, Korea, is scheduled to begin treating cancer patients in 2015.

  11. The first private-hospital based proton therapy center in Korea; Status of the proton therapy center at Samsung Medical Center

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Kwang Zoo; Han, Young Yih; Kim, Jin Sung [Dept. of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); and others

    2015-12-15

    The purpose of this report is to describe the proton therapy system at Samsung Medical Center (SMC-PTS) including the proton beam generator, irradiation system, patient positioning system, patient position verification system, respiratory gating system, and operating and safety control system, and review the current status of the SMC-PTS. The SMC-PTS has a cyclotron (230 MeV) and two treatment rooms: one treatment room is equipped with a multi-purpose nozzle and the other treatment room is equipped with a dedicated pencil beam scanning nozzle. The proton beam generator including the cyclotron and the energy selection system can lower the energy of protons down to 70 MeV from the maximum 230 MeV. The multi-purpose nozzle can deliver both wobbling proton beam and active scanning proton beam, and a multi-leaf collimator has been installed in the downstream of the nozzle. The dedicated scanning nozzle can deliver active scanning proton beam with a helium gas filled pipe minimizing unnecessary interactions with the air in the beam path. The equipment was provided by Sumitomo Heavy Industries Ltd., RayStation from RaySearch Laboratories AB is the selected treatment planning system, and data management will be handled by the MOSAIQ system from Elekta AB. The SMC-PTS located in Seoul, Korea, is scheduled to begin treating cancer patients in 2015.

  12. Feasibility of CBCT-based proton dose calculation using a histogram-matching algorithm in proton beam therapy.

    Science.gov (United States)

    Arai, Kazuhiro; Kadoya, Noriyuki; Kato, Takahiro; Endo, Hiromitsu; Komori, Shinya; Abe, Yoshitomo; Nakamura, Tatsuya; Wada, Hitoshi; Kikuchi, Yasuhiro; Takai, Yoshihiro; Jingu, Keiichi

    2017-01-01

    The aim of this study was to confirm On-Board Imager cone-beam computed tomography (CBCT) using the histogram-matching algorithm as a useful method for proton dose calculation. We studied one head and neck phantom, one pelvic phantom, and ten patients with head and neck cancer treated using intensity-modulated radiation therapy (IMRT) and proton beam therapy. We modified Hounsfield unit (HU) values of CBCT and generated two modified CBCTs (mCBCT-RR, mCBCT-DIR) using the histogram-matching algorithm: modified CBCT with rigid registration (mCBCT-RR) and that with deformable image registration (mCBCT-DIR). Rigid and deformable image registration were applied to match the CBCT to planning CT. To evaluate the accuracy of the proton dose calculation, we compared dose differences in the dosimetric parameters (D2% and D98%) for clinical target volume (CTV) and planning target volume (PTV). We also evaluated the accuracy of the dosimetric parameters (Dmean and D2%) for some organs at risk, and compared the proton ranges (PR) between planning CT (reference) and CBCT or mCBCTs, and the gamma passing rates of CBCT and mCBCTs. For patients, the average dose and PR differences of mCBCTs were smaller than those of CBCT. Additionally, the average gamma passing rates of mCBCTs were larger than those of CBCT (e.g., 94.1±3.5% in mCBCT-DIR vs. 87.8±7.4% in CBCT). We evaluated the accuracy of the proton dose calculation in CBCT and mCBCTs for two phantoms and ten patients. Our results showed that HU modification using the histogram-matching algorithm could improve the accuracy of the proton dose calculation.

  13. Effects of Surgery and Proton Therapy on Cerebral White Matter of Craniopharyngioma Patients

    Energy Technology Data Exchange (ETDEWEB)

    Uh, Jinsoo, E-mail: jinsoo.uh@stjude.org [Department of Radiological Sciences, St Jude Children' s Research Hospital, Memphis, Tennessee (United States); Merchant, Thomas E. [Department of Radiological Sciences, St Jude Children' s Research Hospital, Memphis, Tennessee (United States); Li, Yimei; Li, Xingyu [Department of Biostatistics, St Jude Children' s Research Hospital, Memphis, Tennessee (United States); Sabin, Noah D. [Department of Radiological Sciences, St Jude Children' s Research Hospital, Memphis, Tennessee (United States); Indelicato, Daniel J. [Department of Radiation Oncology, University of Florida, Jacksonville, Florida (United States); Ogg, Robert J. [Department of Radiological Sciences, St Jude Children' s Research Hospital, Memphis, Tennessee (United States); Boop, Frederick A. [Semmes-Murphey Neurologic and Spine Institute, Memphis, Tennessee (United States); Jane, John A. [Department of Neurosurgery, University of Virginia, Charlottesville, Virginia (United States); Hua, Chiaho [Department of Radiological Sciences, St Jude Children' s Research Hospital, Memphis, Tennessee (United States)

    2015-09-01

    Purpose: The purpose of this study was to determine radiation dose effect on the structural integrity of cerebral white matter in craniopharyngioma patients receiving surgery and proton therapy. Methods and Materials: Fifty-one patients (2.1-19.3 years of age) with craniopharyngioma underwent surgery and proton therapy in a prospective therapeutic trial. Anatomical magnetic resonance images acquired after surgery but before proton therapy were inspected to identify white matter structures intersected by surgical corridors and catheter tracks. Longitudinal diffusion tensor imaging (DTI) was performed to measure microstructural integrity changes in cerebral white matter. Fractional anisotropy (FA) derived from DTI was statistically analyzed for 51 atlas-based white matter structures of the brain to determine radiation dose effect. FA in surgery-affected regions in the corpus callosum was compared to that in its intact counterpart to determine whether surgical defects affect radiation dose effect. Results: Surgical defects were seen most frequently in the corpus callosum because of transcallosal resection of tumors and insertion of ventricular or cyst catheters. Longitudinal DTI data indicated reductions in FA 3 months after therapy, which was followed by a recovery in most white matter structures. A greater FA reduction was correlated with a higher radiation dose in 20 white matter structures, indicating a radiation dose effect. The average FA in the surgery-affected regions before proton therapy was smaller (P=.0001) than that in their non–surgery-affected counterparts with more intensified subsequent reduction of FA (P=.0083) after therapy, suggesting that surgery accentuated the radiation dose effect. Conclusions: DTI data suggest that mild radiation dose effects occur in patients with craniopharyngioma receiving surgery and proton therapy. Surgical defects present at the time of proton therapy appear to accentuate the radiation dose effect longitudinally

  14. Measurement of neutron dose equivalent to proton therapy patients outside of the proton radiation field

    CERN Document Server

    Yan, X; Köhler, A; Newhauser, W D

    2002-01-01

    Measurements of neutron dose equivalent values and neutron spectral fluences close to but outside of the therapeutic proton radiation field are presented. The neutron spectral fluences were determined at five locations with Bonner sphere measurements and established by unfolding techniques. More than 50 additional neutron dose equivalent values were measured with LiI and BF sub 3 thermal neutron detectors surrounded by a 25 cm polyethylene moderating sphere. For a large-field treatment, typical values of neutron dose equivalent per therapeutic proton absorbed dose, H/D, at 50 cm distance from isocenter, range from 1 mSv/Gy (at 0 deg.with respect to the proton beam axis) to 5 mSv/Gy (at 90 deg.). Experiments reveal that H/D varies significantly with the treatment technique, e.g., patient orientation, proton beam energy, and range-modulation. The relative uncertainty in H/D values is approximately 40% (one standard deviation).

  15. Principal Possibility of Shaping a Scanned Proton Beam for Application in Radiation Therapy at the JINR LNP Phasotron

    CERN Document Server

    Morozov, N A

    2005-01-01

    of proton irradiation, eliminate the individual boli and figured collimators and increase about 2 or 3 times the throughput capacity of the JINR LNP Medico-Technical Complex or correspondingly decrease the beam time of the Phasotron for proton therapy.

  16. Radiation therapy planning with photons and protons for early and advanced breast cancer: an overview

    Directory of Open Access Journals (Sweden)

    Lomax Antony J

    2006-07-01

    Full Text Available Abstract Postoperative radiation therapy substantially decreases local relapse and moderately reduces breast cancer mortality, but can be associated with increased late mortality due to cardiovascular morbidity and secondary malignancies. Sophistication of breast irradiation techniques, including conformal radiotherapy and intensity modulated radiation therapy, has been shown to markedly reduce cardiac and lung irradiation. The delivery of more conformal treatment can also be achieved with particle beam therapy using protons. Protons have superior dose distributional qualities compared to photons, as dose deposition occurs in a modulated narrow zone, called the Bragg peak. As a result, further dose optimization in breast cancer treatment can be reasonably expected with protons. In this review, we outline the potential indications and benefits of breast cancer radiotherapy with protons. Comparative planning studies and preliminary clinical data are detailed and future developments are considered.

  17. Contemporary Proton Therapy Systems Adequately Protect Patients from Exposure to Stray Radiation

    Science.gov (United States)

    Newhauser, Wayne D.; Fontenot, Jonas D.; Taddei, Phillip J.; Mirkovic, Dragan; Giebeler, Annelise; Zhang, Rui; Mahajan, Anita; Kornguth, David; Stovall, Marilyn; Yepes, Pablo; Woo, Shiao; Mohan, Radhe

    2010-01-01

    Proton beam therapy has provided safe and effective treatments for a variety of adult cancers. In recent years, there has been increasing interest in utilizing proton therapy for pediatric cancers because it allows better sparing of healthy tissues. Minimizing exposures of normal tissues is especially important in children because they are highly susceptible to consequential late effects, including the development of a radiogenic second cancer, which may occur years or even decades after treatment of the first cancer. While the dosimetric advantage of therapeutic proton beams is well understood, relatively little attention has been paid to the whole-body exposure to stray neutron radiation that is inherent in proton therapy. In this report, we review the physical processes that lead to neutron exposures, discuss the potential for mitigating these exposures using advanced proton beam delivery systems, and present a comparative analysis of predicted second cancer incidence following various external beam therapies. In addition, we discuss uncertainties in the relative biological effectiveness of neutrons for carcinogenesis and the impact that these uncertainties have on second-cancer risk predictions for survivors of adult and childhood cancer who receive proton therapy. PMID:20844607

  18. Proton therapy Monte Carlo SRNA-VOX code

    Directory of Open Access Journals (Sweden)

    Ilić Radovan D.

    2012-01-01

    Full Text Available The most powerful feature of the Monte Carlo method is the possibility of simulating all individual particle interactions in three dimensions and performing numerical experiments with a preset error. These facts were the motivation behind the development of a general-purpose Monte Carlo SRNA program for proton transport simulation in technical systems described by standard geometrical forms (plane, sphere, cone, cylinder, cube. Some of the possible applications of the SRNA program are: (a a general code for proton transport modeling, (b design of accelerator-driven systems, (c simulation of proton scattering and degrading shapes and composition, (d research on proton detectors; and (e radiation protection at accelerator installations. This wide range of possible applications of the program demands the development of various versions of SRNA-VOX codes for proton transport modeling in voxelized geometries and has, finally, resulted in the ISTAR package for the calculation of deposited energy distribution in patients on the basis of CT data in radiotherapy. All of the said codes are capable of using 3-D proton sources with an arbitrary energy spectrum in an interval of 100 keV to 250 MeV.

  19. The influence of the channel size on the reduction of side effects in microchannel proton therapy.

    Science.gov (United States)

    Girst, Stefanie; Greubel, Christoph; Reindl, Judith; Siebenwirth, Christian; Zlobinskaya, Olga; Dollinger, Günther; Schmid, Thomas E

    2015-08-01

    The potential of proton microchannel radiotherapy to reduce radiation effects in the healthy tissue but to keep tumor control the same as in conventional proton therapy is further elucidated. The microchannels spread on their way to the tumor tissue resulting in different fractions of the healthy tissue covered with doses larger than the tumor dose, while the tumor gets homogeneously irradiated. The aim of this study was to evaluate the effect of increasing channel width on potential side effects in the normal tissue. A rectangular 180 × 180 µm(2) and two Gaussian-type dose distributions of σ = 260 µm and σ = 520 µm with an interchannel distance of 1.8 mm have been applied by 20-MeV protons to a 3D human skin model in order to simulate the widened channels and to compare the irradiation effects at different endpoints to those of a homogeneous proton irradiation. The number of protons applied was kept constant at all irradiation modes resulting in the same average dose of 2 Gy. All kinds of proton microchannel irradiation lead to higher cell viability and produce significantly less genetic damage than homogeneous proton irradiation, but the reduction is lower for the wider channel sizes. Our findings point toward the application of microchannel irradiation for clinical proton or heavy ion therapy to further reduce damage of normal tissues while maintaining tumor control via a homogeneous dose distribution inside the tumor.

  20. Noise evaluation of Compton camera imaging for proton therapy

    Science.gov (United States)

    Ortega, P. G.; Torres-Espallardo, I.; Cerutti, F.; Ferrari, A.; Gillam, J. E.; Lacasta, C.; Llosá, G.; Oliver, J. F.; Sala, P. R.; Solevi, P.; Rafecas, M.

    2015-02-01

    Compton Cameras emerged as an alternative for real-time dose monitoring techniques for Particle Therapy (PT), based on the detection of prompt-gammas. As a consequence of the Compton scattering process, the gamma origin point can be restricted onto the surface of a cone (Compton cone). Through image reconstruction techniques, the distribution of the gamma emitters can be estimated, using cone-surfaces backprojections of the Compton cones through the image space, along with more sophisticated statistical methods to improve the image quality. To calculate the Compton cone required for image reconstruction, either two interactions, the last being photoelectric absorption, or three scatter interactions are needed. Because of the high energy of the photons in PT the first option might not be adequate, as the photon is not absorbed in general. However, the second option is less efficient. That is the reason to resort to spectral reconstructions, where the incoming γ energy is considered as a variable in the reconstruction inverse problem. Jointly with prompt gamma, secondary neutrons and scattered photons, not strongly correlated with the dose map, can also reach the imaging detector and produce false events. These events deteriorate the image quality. Also, high intensity beams can produce particle accumulation in the camera, which lead to an increase of random coincidences, meaning events which gather measurements from different incoming particles. The noise scenario is expected to be different if double or triple events are used, and consequently, the reconstructed images can be affected differently by spurious data. The aim of the present work is to study the effect of false events in the reconstructed image, evaluating their impact in the determination of the beam particle ranges. A simulation study that includes misidentified events (neutrons and random coincidences) in the final image of a Compton Telescope for PT monitoring is presented. The complete chain of

  1. Noise evaluation of Compton camera imaging for proton therapy.

    Science.gov (United States)

    Ortega, P G; Torres-Espallardo, I; Cerutti, F; Ferrari, A; Gillam, J E; Lacasta, C; Llosá, G; Oliver, J F; Sala, P R; Solevi, P; Rafecas, M

    2015-03-07

    Compton Cameras emerged as an alternative for real-time dose monitoring techniques for Particle Therapy (PT), based on the detection of prompt-gammas. As a consequence of the Compton scattering process, the gamma origin point can be restricted onto the surface of a cone (Compton cone). Through image reconstruction techniques, the distribution of the gamma emitters can be estimated, using cone-surfaces backprojections of the Compton cones through the image space, along with more sophisticated statistical methods to improve the image quality. To calculate the Compton cone required for image reconstruction, either two interactions, the last being photoelectric absorption, or three scatter interactions are needed. Because of the high energy of the photons in PT the first option might not be adequate, as the photon is not absorbed in general. However, the second option is less efficient. That is the reason to resort to spectral reconstructions, where the incoming γ energy is considered as a variable in the reconstruction inverse problem. Jointly with prompt gamma, secondary neutrons and scattered photons, not strongly correlated with the dose map, can also reach the imaging detector and produce false events. These events deteriorate the image quality. Also, high intensity beams can produce particle accumulation in the camera, which lead to an increase of random coincidences, meaning events which gather measurements from different incoming particles. The noise scenario is expected to be different if double or triple events are used, and consequently, the reconstructed images can be affected differently by spurious data. The aim of the present work is to study the effect of false events in the reconstructed image, evaluating their impact in the determination of the beam particle ranges. A simulation study that includes misidentified events (neutrons and random coincidences) in the final image of a Compton Telescope for PT monitoring is presented. The complete chain of

  2. Accelerated prompt gamma estimation for clinical proton therapy simulations

    Science.gov (United States)

    Huisman, Brent F. B.; Létang, J. M.; Testa, É.; Sarrut, D.

    2016-11-01

    There is interest in the particle therapy community in using prompt gammas (PGs), a natural byproduct of particle treatment, for range verification and eventually dose control. However, PG production is a rare process and therefore estimation of PGs exiting a patient during a proton treatment plan executed by a Monte Carlo (MC) simulation converges slowly. Recently, different approaches to accelerating the estimation of PG yield have been presented. Sterpin et al (2015 Phys. Med. Biol. 60 4915-46) described a fast analytic method, which is still sensitive to heterogeneities. El Kanawati et al (2015 Phys. Med. Biol. 60 8067-86) described a variance reduction method (pgTLE) that accelerates the PG estimation by precomputing PG production probabilities as a function of energy and target materials, but has as a drawback that the proposed method is limited to analytical phantoms. We present a two-stage variance reduction method, named voxelized pgTLE (vpgTLE), that extends pgTLE to voxelized volumes. As a preliminary step, PG production probabilities are precomputed once and stored in a database. In stage 1, we simulate the interactions between the treatment plan and the patient CT with low statistic MC to obtain the spatial and spectral distribution of the PGs. As primary particles are propagated throughout the patient CT, the PG yields are computed in each voxel from the initial database, as a function of the current energy of the primary, the material in the voxel and the step length. The result is a voxelized image of PG yield, normalized to a single primary. The second stage uses this intermediate PG image as a source to generate and propagate the number of PGs throughout the rest of the scene geometry, e.g. into a detection device, corresponding to the number of primaries desired. We achieved a gain of around 103 for both a geometrical heterogeneous phantom and a complete patient CT treatment plan with respect to analog MC, at a convergence level of 2% relative

  3. What will it take for laser driven proton accelerators to be applied to tumor therapy?

    Science.gov (United States)

    Linz, Ute; Alonso, Jose

    2007-09-01

    After many years on the periphery of cancer therapy, the successes of proton and ion beams in tumor therapy are gradually receiving a higher degree of recognition. The considerable construction and acquisition costs are usually invoked to explain the slow market penetration of this favorable treatment modality. Recently, high-intensity lasers have been suggested as a potential, cost-saving alternative to cyclotrons or synchrotrons for oncology. This article will detail the technical requirements necessary for successful implementation of ion beam therapy (IBT)—the general term for proton and heavier-ion therapy. It will summarize the current state of laser acceleration of protons and will outline the very substantial developments still necessary for this technology to be successfully applied to IBT.

  4. Impact of Various Beam Parameters on Lateral Scattering in Proton and Carbon-ion Therapy

    Directory of Open Access Journals (Sweden)

    Ebrahimi Loushab M.

    2015-12-01

    Full Text Available Background: In radiation therapy with ion beams, lateral distributions of absorbed dose in the tissue are important. Heavy ion therapy, such as carbon-ion therapy, is a novel technique of high-precision external radiotherapy which has advantages over proton therapy in terms of dose locality and biological effectiveness. Methods: In this study, we used Monte Carlo method-based Geant4 toolkit to simulate and calculate the effects of energy, shape and type of ion beams incident upon water on multiple scattering processes. Nuclear reactions have been taken into account in our calculation. A verification of this approach by comparing experimental data and Monte Carlo methods will be presented in an upcoming paper. Results: Increasing particle energies, the width of the Bragg curve becomes larger but with increasing mass of particles, the width of the Bragg curve decreases. This is one of the advantages of carbon-ion therapy to treat with proton. The transverse scattering of dose distribution is increased with energy at the end of heavy ion beam range. It can also be seen that the amount of the dose scattering for carbon-ion beam is less than that of proton beam, up to about 160mm depth in water. Conclusion: The distortion of Bragg peak profiles, due to lateral scattering of carbon-ion, is less than proton. Although carbon-ions are primarily scattered less than protons, the corresponding dose distributions, especially the lateral dose, are not much less.

  5. Impact of Various Beam Parameters on Lateral Scattering in Proton and Carbon-ion Therapy

    Science.gov (United States)

    Ebrahimi Loushab, M.; Mowlavi, A.A.; Hadizadeh, M.H.; Izadi, R.; Jia, S.B.

    2015-01-01

    Background In radiation therapy with ion beams, lateral distributions of absorbed dose in the tissue are important. Heavy ion therapy, such as carbon-ion therapy, is a novel technique of high-precision external radiotherapy which has advantages over proton therapy in terms of dose locality and biological effectiveness. Methods In this study, we used Monte Carlo method-based Geant4 toolkit to simulate and calculate the effects of energy, shape and type of ion beams incident upon water on multiple scattering processes. Nuclear reactions have been taken into account in our calculation. A verification of this approach by comparing experimental data and Monte Carlo methods will be presented in an upcoming paper. Results Increasing particle energies, the width of the Bragg curve becomes larger but with increasing mass of particles, the width of the Bragg curve decreases. This is one of the advantages of carbon-ion therapy to treat with proton. The transverse scattering of dose distribution is increased with energy at the end of heavy ion beam range. It can also be seen that the amount of the dose scattering for carbon-ion beam is less than that of proton beam, up to about 160mm depth in water. Conclusion The distortion of Bragg peak profiles, due to lateral scattering of carbon-ion, is less than proton. Although carbon-ions are primarily scattered less than protons, the corresponding dose distributions, especially the lateral dose, are not much less. PMID:26688795

  6. Quantitative analysis of proton boron fusion therapy (PBFT) in various conditions

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Joo-Young; Yoon, Do-Kun; Suh, Tae Suk [College of Medicine, Catholic University of Korea, Seoul (Korea, Republic of)

    2015-05-15

    From the theoretical point of view, the PBFT has some strong advantages over currently existing radiotherapy methods. First, boron-based tumor targeting is required prior to performing the treatments such as boron-neutron capture therapy (BNCT). Tumor targeting should be performed before the BNCT by injecting the boronate compound. If boron is not taken up by the normal tissue, the normal tissue can be spared the irradiation by alpha particles. When boron uptake occurs in the target region, selective therapy is possible by neutron capture reaction of labeled boron particles in the target region. Likewise, when boron is distributed in the tumor region for the PBFT, the proposed method can represent a more critical discriminative therapy than either the BNCT or conventional particle therapy. In the conventional proton therapy, in order to deliver a dose to a tumor, the proton beam energy has to be adjusted along the tumor region (e.g., shape and depth). The proton therapy aims at delivering the maximal dose to the tumor by using protons only. In this study, the effectiveness of the PBFT with respect to several physical parameters was evaluated quantitatively by using Monte Carlo simulations. We confirmed that the PBFT can be used to perform critical discriminative therapy. Also, the results of our studies can be used for constructing the PFBT dose database that can be utilized in treatment planning systems (TPSs)

  7. Dosimetric investigation of proton therapy on CT-based patient data using Monte Carlo simulation

    Science.gov (United States)

    Chongsan, T.; Liamsuwan, T.; Tangboonduangjit, P.

    2016-03-01

    The aim of radiotherapy is to deliver high radiation dose to the tumor with low radiation dose to healthy tissues. Protons have Bragg peaks that give high radiation dose to the tumor but low exit dose or dose tail. Therefore, proton therapy is promising for treating deep- seated tumors and tumors locating close to organs at risk. Moreover, the physical characteristic of protons is suitable for treating cancer in pediatric patients. This work developed a computational platform for calculating proton dose distribution using the Monte Carlo (MC) technique and patient's anatomical data. The studied case is a pediatric patient with a primary brain tumor. PHITS will be used for MC simulation. Therefore, patient-specific CT-DICOM files were converted to the PHITS input. A MATLAB optimization program was developed to create a beam delivery control file for this study. The optimization program requires the proton beam data. All these data were calculated in this work using analytical formulas and the calculation accuracy was tested, before the beam delivery control file is used for MC simulation. This study will be useful for researchers aiming to investigate proton dose distribution in patients but do not have access to proton therapy machines.

  8. The investigation of physical conditions of boron uptake region in proton boron fusion therapy (PBFT)

    Science.gov (United States)

    Jung, Joo-Young; Yoon, Do-Kun; Lee, Heui Chang; Lu, Bo; Suh, Tae Suk

    2016-09-01

    We conducted a quantitative study to identify the effectiveness of proton boron fusion therapy (PBFT). Four simulation scenarios were designed to investigate the escalation in total dose with the proton boron reaction using a Monte Carlo n-particle extended (MCNPX 2.6.0) simulation. The peak integrated dose was obtained for three different physical conditions (i.e., boron uptake region (BUR) thickness, BUR location, and boron concentration) with differing proton beam energy (60-90 MeV). We found that the peak integrated dose was increased by up to 96.62% compared to the pristine proton Bragg-peak. For the synergetic effect to take place with 60-70 MeV proton beam, the BUR had to be at least 0.3 cm thick while spanning the Bragg-peak. Similarly to the thickness, the BUR location needed to be within 0.3 cm from the Bragg-peak when the thickness was maintained at 0.9 cm. An effective proton boron reaction required the boron concentration to be equal to or greater than 14.4 mg/g. These results demonstrate the impact of various physical and beam conditions of the PBFT, which are critical environmental factors for the treatment planning. We envision that this study will advance our understanding of the PBFT, which can be an invaluable treatment method for maximizing the potential of proton therapy.

  9. The investigation of physical conditions of boron uptake region in proton boron fusion therapy (PBFT

    Directory of Open Access Journals (Sweden)

    Joo-Young Jung

    2016-09-01

    Full Text Available We conducted a quantitative study to identify the effectiveness of proton boron fusion therapy (PBFT. Four simulation scenarios were designed to investigate the escalation in total dose with the proton boron reaction using a Monte Carlo n-particle extended (MCNPX 2.6.0 simulation. The peak integrated dose was obtained for three different physical conditions (i.e., boron uptake region (BUR thickness, BUR location, and boron concentration with differing proton beam energy (60–90 MeV. We found that the peak integrated dose was increased by up to 96.62% compared to the pristine proton Bragg-peak. For the synergetic effect to take place with 60–70 MeV proton beam, the BUR had to be at least 0.3 cm thick while spanning the Bragg-peak. Similarly to the thickness, the BUR location needed to be within 0.3 cm from the Bragg-peak when the thickness was maintained at 0.9 cm. An effective proton boron reaction required the boron concentration to be equal to or greater than 14.4 mg/g. These results demonstrate the impact of various physical and beam conditions of the PBFT, which are critical environmental factors for the treatment planning. We envision that this study will advance our understanding of the PBFT, which can be an invaluable treatment method for maximizing the potential of proton therapy.

  10. TL and TSC Solid State Detectors in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Cirrone, G.A.P.; Sabini, M.G.; Bruzzi, M.; Bucciolini, M.; Cuttone, G.; Guasti, A.; Lo Nigro, S.; Mazzocchi, S.; Pirollo, S.; Raffaele, L.; Sciortino, S.

    2000-12-31

    The necessity to develop methods and techniques for a better determination of absorbed dose in the radiotherapy field stimulates new clinical applications of solid state detectors. In this work we have studied the possibility to use of TLD-100 and synthetic CVD diamond detectors as dosimeters for high-energy proton beams.

  11. Potential proton beam therapy for recurrent endometrial cancer in the vagina.

    Science.gov (United States)

    Yanazume, Shintaro; Arimura, Takeshi; Kobayashi, Hiroaki; Douchi, Tsutomu

    2015-05-01

    Proton beam radiotherapy mainly has been used in the gynecological field in patients with cervical cancer. The efficacy of proton beam therapy in patients with recurrent endometrial cancer has not yet been determined. A 77-year-old endometrial cancer patient presented with recurrence in the vagina without distant metastasis following hysterectomy. A hard mass measuring 6 cm originated from the apex of the vagina, surrounded the vaginal cavity, and infiltrated the proximal and distal vagina. The patient received proton beam radiotherapy using a less invasive particle treatment system while minimizing the dose to the surrounding normal tissues. The dose to the planning target volume was 74 Gy (relative biological effectiveness) with 37 fractions. The patient was treated with 150-210-MeV proton beams for 53 days. Proton beam therapy led to the disappearance of tumors without any complications except for grade 1 cystitis although evidence of further complications is not available past our 6-month follow-up period. Proton beam therapy may become a useful treatment modality for recurrent endometrial cancer as well as cervical uterine cancer. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

  12. Effective Dose from Stray Radiation for a Patient Receiving Proton Therapy for Liver Cancer

    Science.gov (United States)

    Taddei, Phillip J; Krishnan, Sunil; Mirkovic, Dragan; Yepes, Pablo; Newhauser, Wayne D

    2010-01-01

    Because of its advantageous depth-dose relationship, proton radiotherapy is an emerging treatment modality for patients with liver cancer. Although the proton dose distribution conforms to the target, healthy tissues throughout the body receive low doses of stray radiation, particularly neutrons that originate in the treatment unit or in the patient. The aim of this study was to calculate the effective dose from stray radiation and estimate the corresponding risk of second cancer fatality for a patient receiving proton beam therapy for liver cancer. Effective dose from stray radiation was calculated using detailed Monte Carlo simulations of a double-scattering proton therapy treatment unit and a voxelized human phantom. The treatment plan and phantom were based on CT images of an actual adult patient diagnosed with primary hepatocellular carcinoma. For a prescribed dose of 60 Gy to the clinical target volume, the effective dose from stray radiation was 370 mSv; 61% of this dose was from neutrons originating outside of the patient while the remaining 39% was from neutrons originating within the patient. The excess lifetime risk of fatal second cancer corresponding to the total effective dose from stray radiation was 1.2%. The results of this study establish a baseline estimate of the stray radiation dose and corresponding risk for an adult patient undergoing proton radiotherapy for liver cancer and provide new evidence to corroborate the suitability of proton beam therapy for the treatment of liver tumors. PMID:20865142

  13. Dose Assessment of Eye and Its Components in Proton Therapy by Monte Carlo Method

    Directory of Open Access Journals (Sweden)

    Marzieh Tavakol

    2014-04-01

    Full Text Available Introduction Proton therapy is used to treat malignant tumors such as melanoma inside the eye. Proton particles are adjusted according to various parameters such as tumor size and position and patient’s distance from the proton source. The purpose of this study was to assess absorbed doses in eyes and various tumors found in the area of sclera and choroid and the adjacent tissues in radiotherapy while changing most important proton therapy parameters such as moderators thickness (1.5-1.9 cm, exposure radius (0.5-0.8 cm, and proton energy beam (53.5-65 MeV. Materials and Methods A proton therapy system of Laboratori Nazionali del Sud-INFNwas simulated by Monte Carlo method. Moreover, the eye and its components were simulated using concentric spheres. To obtain a more accurate results, real density of eye components such as cornea and lens, were applied for simulation. Then, the absorbed dose of eye and eye tumor, in choroid and sclera areas, were calculated by Monte Carlo method. Results The absorbed dose in tumoral region of eye was calculated to be about 12.5 ±0.006Gy in one day with energy 62 MeV for a therapy session, which is suitable for treatment. However, normal eye cells received at most 11.01 Gy which is high. Conclusion The amount of absorbed dose in tumoral cells is noticeable. Therefore, accurate treatment planning, patient immobility and fine calibration of proton-therapy system and its simulator are very important to reduce the absorbed dose of healthy cells.

  14. SU-E-J-175: Proton Dose Calculation On Scatter-Corrected CBCT Image: Feasibility Study for Adaptive Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y; Winey, B; Sharp, G [Massachusetts General Hospital, Boston, MA (United States)

    2014-06-01

    Purpose: To demonstrate feasibility of proton dose calculation on scattercorrected CBCT images for the purpose of adaptive proton therapy. Methods: Two CBCT image sets were acquired from a prostate cancer patient and a thorax phantom using an on-board imaging system of an Elekta infinity linear accelerator. 2-D scatter maps were estimated using a previously introduced CT-based technique, and were subtracted from each raw projection image. A CBCT image set was then reconstructed with an open source reconstruction toolkit (RTK). Conversion from the CBCT number to HU was performed by soft tissue-based shifting with reference to the plan CT. Passively scattered proton plans were simulated on the plan CT and corrected/uncorrected CBCT images using the XiO treatment planning system. For quantitative evaluation, water equivalent path length (WEPL) was compared in those treatment plans. Results: The scatter correction method significantly improved image quality and HU accuracy in the prostate case where large scatter artifacts were obvious. However, the correction technique showed limited effects on the thorax case that was associated with fewer scatter artifacts. Mean absolute WEPL errors from the plans with the uncorrected and corrected images were 1.3 mm and 5.1 mm in the thorax case and 13.5 mm and 3.1 mm in the prostate case. The prostate plan dose distribution of the corrected image demonstrated better agreement with the reference one than that of the uncorrected image. Conclusion: A priori CT-based CBCT scatter correction can reduce the proton dose calculation error when large scatter artifacts are involved. If scatter artifacts are low, an uncorrected CBCT image is also promising for proton dose calculation when it is calibrated with the soft-tissue based shifting.

  15. Improving the therapeutic ratio by using proton therapy in patients with stage I or II seminoma.

    Science.gov (United States)

    Hoppe, Bradford S; Mamalui-Hunter, Maria; Mendenhall, Nancy P; Li, Zuofeng; Indelicato, Daniel J

    2013-02-01

    The goal of the present study was to evaluate possible dosimetric advantages of proton therapy (PT) compared with 3-dimensional conformal radiotherapy (3DCRT) or intensity-modulated radiotherapy (IMRT) in the treatment of patients with stage I and II seminoma. Two representative patients (1 with left-sided and 1 with right-sided seminoma) underwent treatment planning for stage I seminoma (paraaortic lymph nodes alone) with 3DCRT (PA3d), IMRT (PAimrt) double-scatter protons (PAPds), and uniform-scanning protons (PAPus) and for stage II seminoma (paraaortics lymph nodes and iliac nodes) with 3DCRT (PI3d) , IMRT (PIimrt) double-scatter protons (PIPds), and uniform-scanning protons (PIPus). The doses to the organs at risk were compared for photons and protons. For stage I seminoma, PT reduced the mean dose to the stomach, ipsilateral kidney, pancreas, bowel space, small bowel, and colon compared with 3DCRT and IMRT. For stage II seminoma, PT reduced the mean dose to the same organs as in stage I seminoma with additional reductions in mean dose to the bladder and rectum compared with 3DCRT and IMRT. Uniform-scanning protons further reduced the dose to the organs at risk compared with double-scatter protons. PT may offer an improvement in the therapeutic ratio in patients with seminoma by reducing the dose to normal tissue. This improvement may translate into lower risks of acute gastrointestinal side effects, infertility, and secondary malignancies, which should be explored in a prospective study.

  16. Development of proton computed tomography detectors for applications in hadron therapy

    Energy Technology Data Exchange (ETDEWEB)

    Bashkirov, Vladimir A., E-mail: vbashkirov@llu.edu [Loma Linda University, 11175 Campus Street, Loma Linda 92354 (United States); Johnson, Robert P.; Sadrozinski, Hartmut F.-W. [University of California, Santa Cruz, 1156 High Street, Santa Cruz 95064 (United States); Schulte, Reinhard W. [Loma Linda University, 11175 Campus Street, Loma Linda 92354 (United States)

    2016-02-11

    Radiation therapy with protons and heavier ions is an attractive form of cancer treatment that could enhance local control and survival of cancers that are currently difficult to cure and lead to less side effects due to sparing of normal tissues. However, particle therapy faces a significant technical challenge because one cannot accurately predict the particle range in the patient using data provided by existing imaging technologies. Proton computed tomography (pCT) is an emerging imaging modality capable of improving the accuracy of range prediction. In this paper, we describe the successive pCT scanners designed and built by our group with the goal to support particle therapy treatment planning and image guidance by reconstructing an accurate 3D map of the stopping power relative to water in patient tissues. The pCT scanners we have built to date consist of silicon telescopes, which track the proton before and after the object to be reconstructed, and an energy or range detector, which measures the residual energy and/or range of the protons used to evaluate the water equivalent path length (WEPL) of each proton in the object. An overview of a decade-long evolution of the conceptual design of pCT scanners and their calibration is given. Results of scanner performance tests are presented, which demonstrate that the latest pCT scanner approaches readiness for clinical applications in hadron therapy.

  17. Design and application of 3D-printed stepless beam modulators in proton therapy

    Science.gov (United States)

    Lindsay, C.; Kumlin, J.; Martinez, D. M.; Jirasek, A.; Hoehr, C.

    2016-06-01

    A new method for the design of stepless beam modulators for proton therapy is described and verified. Simulations of the classic designs are compared against the stepless method for various modulation widths which are clinically applicable in proton eye therapy. Three modulator wheels were printed using a Stratasys Objet30 3D printer. The resulting depth dose distributions showed improved uniformity over the classic stepped designs. Simulated results imply a possible improvement in distal penumbra width; however, more accurate measurements are needed to fully verify this effect. Lastly, simulations were done to model bio-equivalence to Co-60 cell kill. A wheel was successfully designed to flatten this metric.

  18. Proton Therapy At Siteman Cancer Center: The State Of The Art

    Science.gov (United States)

    Bloch, Charles

    2011-06-01

    Barnes-Jewish Hospital is on the verge of offering proton radiation therapy to its patients. Those treatments will be delivered from the first Monarch 250, a state-of-the-art cyclotron produced by Still River Systems, Inc., Littleton, MA. The accelerator is the world's first superconducting synchrocyclotron, with a field-strength of 10 tesla, providing the smallest accelerator for high-energy protons currently available. On May 14, 2010 it was announced that the first production unit had successfully extracted 250 MeV protons. That unit is scheduled for delivery to the Siteman Cancer Center, an NCI-designated Comprehensive Cancer Center at Washington University School of Medicine. At a weight of 20 tons and with a diameter of less than 2 meters the compact cyclotron will be mounted on a gantry, another first for proton therapy systems. The single-energy system includes 3 contoured scatterers and 14 different range modulators to provide 24 distinct beam delivery configurations. This allows proton fields up to 25 cm in diameter, with a maximum range from 5.5 to 32 cm and spread-out-Bragg-peak extent up to 20 cm. Monte Carlo simulations have been run using MCNPX to simulate the clinical beam properties. Those calculations have been used to commission a commercial treatment planning system prior to final clinical measurements. MCNPX was also used to calculate the neutron background generated by protons in the scattering system and patient. Additional details of the facility and current status will be presented.

  19. Effects of defining realistic compositions of the ocular melanoma on proton therapy.

    Science.gov (United States)

    Keshazare, Sh; Masoudi, S F; S Rasouli, F

    2014-12-01

    Recent studies in eye plaque brachytherapy have shown a considerable difference between the dosimetric results using water phantom and a model of human eye containing realistic materials. In spite of this fact, there is a lack of simulation studies based on such a model in proton therapy literatures. In the presented work, the effect of utilizing an eye model with ocular media on proton therapy is investigated using the MCNPX Monte Carlo Code. Two different eye models are proposed to study the effect of defining realistic materials on dose deposition due to utilizing pencil beam scanning (PBS) method for proton therapy of ocular melanoma. The first model is filled with water, and the second one contains the realistic materials of tumor and vitreous. Spread out Bragg peaks (SOBP) are created to cover a typical tumor volume. Moreover, isodose curves are figured in order to evaluate planar variations of absorbed dose in two models. The results show that the maximum delivered dose in ocular media is approximately 12-32% more than in water phantom. Also it is found that using the optimized weighted beams in water phantom leads to disturbance of uniformity of SOBP in ocular media. Similar to the results reported in eye brachytherapy published papers, considering the ocular media in simulation studies leads to a more realistic assessment of sufficiency of the designed proton beam in tissue. This effect is of special importance in creating SOBP, as well as in delivered dose in the tumor boundaries in proton pencil beam scanning method.

  20. An end-to-end assessment of range uncertainty in proton therapy using animal tissues

    Science.gov (United States)

    Zheng, Yuanshui; Kang, Yixiu; Zeidan, Omar; Schreuder, Niek

    2016-11-01

    Accurate assessment of range uncertainty is critical in proton therapy. However, there is a lack of data and consensus on how to evaluate the appropriate amount of uncertainty. The purpose of this study is to quantify the range uncertainty in various treatment conditions in proton therapy, using transmission measurements through various animal tissues. Animal tissues, including a pig head, beef steak, and lamb leg, were used in this study. For each tissue, an end-to-end test closely imitating patient treatments was performed. This included CT scan simulation, treatment planning, image-guided alignment, and beam delivery. Radio-chromic films were placed at various depths in the distal dose falloff region to measure depth dose. Comparisons between measured and calculated doses were used to evaluate range differences. The dose difference at the distal falloff between measurement and calculation depends on tissue type and treatment conditions. The estimated range difference was up to 5, 6 and 4 mm for the pig head, beef steak, and lamb leg irradiation, respectively. Our study shows that the TPS was able to calculate proton range within about 1.5% plus 1.5 mm. Accurate assessment of range uncertainty in treatment planning would allow better optimization of proton beam treatment, thus fully achieving proton beams’ superior dose advantage over conventional photon-based radiation therapy.

  1. Prompt gamma-ray emission for future imaging applications in proton-boron fusion therapy

    Science.gov (United States)

    Petringa, G.; Cirrone, G. A. P.; Caliri, C.; Cuttone, G.; Giuffrida, L.; La Rosa, G.; Manna, R.; Manti, L.; Marchese, V.; Marchetta, C.; Margarone, D.; Milluzzo, G.; Picciotto, A.; Romano, F.; Romano, F. P.; Russo, A. D.; Russo, G.; Santonocito, D.; Scuderi, V.

    2017-03-01

    Recently, an approach exploiting the proton therapy biological enhancement by using Boron atoms injected inside a tumor, has been proposed [1-3]. Here, the 11B(p,α)2α nuclear fusion reaction channel, where three alpha particles are produced with an average energy around 4 MeV, is considered [4]. These alphas are able to penetrate the cells nucleus and strongly damage their DNA. In addition, gamma prompts emitted by the proton Boron nuclear reactions can be used for on-line proton beam imaging purposes. In this work an experimental study of the gamma prompt emissions from the proton Boron nuclear reactions has been carried out with the main aim to understand and quantify the most probable emission for future clinical applications.

  2. A treatment planning study of the potential of geometrical tracking for intensity modulated proton therapy of lung cancer

    DEFF Research Database (Denmark)

    af Rosenschöld, Per Munck; Aznar, Marianne C; Nygaard, Ditte E;

    2010-01-01

    Proton therapy of lung cancer holds the potential for a reduction of the volume of irradiated normal lung tissue. In this work we investigate the robustness of intensity modulated proton therapy (IMPT) plans to motion, and evaluate a geometrical tumour tracking method to compensate for tumour...

  3. Predicted Rates of Secondary Malignancies From Proton Versus Photon Radiation Therapy for Stage I Seminoma

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Charles B., E-mail: csimone@alumni.upenn.edu [Department of Radiation Oncology, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania (United States); Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Kramer, Kevin [Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, Maryland (United States); O' Meara, William P. [Division of Radiation Oncology, National Naval Medical Center, Bethesda, Maryland (United States); Bekelman, Justin E. [Department of Radiation Oncology, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania (United States); Belard, Arnaud [Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, Maryland (United States); McDonough, James [Department of Radiation Oncology, Hospital of University of Pennsylvania, Philadelphia, Pennsylvania (United States); O' Connell, John [Radiation Oncology Service, Walter Reed Army Medical Center, Washington, DC (United States)

    2012-01-01

    Purpose: Photon radiotherapy has been the standard adjuvant treatment for stage I seminoma. Single-dose carboplatin therapy and observation have emerged as alternative options due to concerns for acute toxicities and secondary malignancies from radiation. In this institutional review board-approved study, we compared photon and proton radiotherapy for stage I seminoma and the predicted rates of excess secondary malignancies for both treatment modalities. Methods and Material: Computed tomography images from 10 consecutive patients with stage I seminoma were used to quantify dosimetric differences between photon and proton therapies. Structures reported to be at increased risk for secondary malignancies and in-field critical structures were contoured. Reported models of organ-specific radiation-induced cancer incidence rates based on organ equivalent dose were used to determine the excess absolute risk of secondary malignancies. Calculated values were compared with tumor registry reports of excess secondary malignancies among testicular cancer survivors. Results: Photon and proton plans provided comparable target volume coverage. Proton plans delivered significantly lower mean doses to all examined normal tissues, except for the kidneys. The greatest absolute reduction in mean dose was observed for the stomach (119 cGy for proton plans vs. 768 cGy for photon plans; p < 0.0001). Significantly more excess secondary cancers per 10,000 patients/year were predicted for photon radiation than for proton radiation to the stomach (4.11; 95% confidence interval [CI], 3.22-5.01), large bowel (0.81; 95% CI, 0.39-1.01), and bladder (0.03; 95% CI, 0.01-0.58), while no difference was demonstrated for radiation to the pancreas (0.02; 95% CI, -0.01-0.06). Conclusions: For patients with stage I seminoma, proton radiation therapy reduced the predicted secondary cancer risk compared with photon therapy. We predict a reduction of one additional secondary cancer for every 50 patients

  4. Total variation superiorization in dual-energy CT reconstruction for proton therapy treatment planning

    Science.gov (United States)

    Zhu, Jiahua; Penfold, Scott

    2017-04-01

    Proton therapy is a precise form of radiotherapy in which the range of an energetic beam of protons within a patient must be accurately known. The current approach based on single-energy computed tomography (SECT) can lead to uncertainties in the proton range of approximately 3%. This range of uncertainty may lead to under-dosing of the tumour or over-dosing of healthy tissues. Dual-energy CT (DECT) theoretically has the potential to reduce these range uncertainties by quantifying electron density and the effective atomic number. In practice, however, DECT images reconstructed with filtered backprojection (FBP) tend to suffer from high levels of noise. The objective of the current work was to examine the effect of total variation superiorization (TVS) on proton therapy planning accuracy when compared with FBP. A virtual CT scanner was created with the Monte Carlo toolkit Geant4. Tomographic images were reconstructed with FBP and TVS combined with diagonally relaxed orthogonal projections (TVS-DROP). A total variation minimization (TVM) filter was also applied to the image reconstructed with FBP (FBP-TVM). Quantitative accuracy and variance of proton relative stopping power (RSP) derived from each image set was assessed. Mean RSPs were comparable with each image; however, the standard deviation of pixel values with TVS-DROP was reduced by a factor of 0.44 compared with the FBP image and a factor of 0.66 when compared with the FBP-TVM image. Proton doses calculated with the TVS-DROP image set were also better able to predict a reference dose distribution when compared with the FBP and FBP-TVM image sets. The study demonstrated the potential advantages of TVS-DROP as an image reconstruction method for DECT applied to proton therapy treatment planning.

  5. Use of a two-dimensional ionization chamber array for proton therapy beam quality assurance.

    Science.gov (United States)

    Arjomandy, Bijan; Sahoo, Narayan; Ding, Xiaoning; Gillin, Michael

    2008-09-01

    Two-dimensional ion chamber arrays are primarily used for conventional and intensity modulated radiotherapy quality assurance. There is no commercial device of such type available on the market that is offered for proton therapy quality assurance. We have investigated suitability of the MatriXX, a commercial two-dimensional ion chamber array detector for proton therapy QA. This device is designed to be used for photon and electron therapy QA. The device is equipped with 32 x 32 parallel plate ion chambers, each with 4.5 mm diam and 7.62 mm center-to-center separation. A 250 MeV proton beam was used to calibrate the dose measured by this device. The water equivalent thickness of the buildup material was determined to be 3.9 mm using a 160 MeV proton beam. Proton beams of different energies were used to measure the reproducibility of dose output and to evaluate the consistency in the beam flatness and symmetry measured by MatriXX. The output measurement results were compared with the clinical commissioning beam data that were obtained using a 0.6 cc Farmer chamber. The agreement was consistently found to be within 1%. The profiles were compared with film dosimetry and also with ion chamber data in water with an excellent agreement. The device is found to be well suited for quality assurance of proton therapy beams. It provides fast two-dimensional dose distribution information in real time with the accuracy comparable to that of ion chamber measurements and film dosimetry.

  6. Development of a pixel ionization chamber for beam monitor in proton therapy

    Science.gov (United States)

    La Rosa, A.; Garella, M. A.; Attili, A.; Bourhaleb, F.; Cirio, R.; Donetti, M.; Giordanengo, S.; Givehchi, N.; Marchetto, F.; Mazza, G.; Meyroneinc, S.; Pecka, A.; Peroni, C.; Pittà, G.

    2007-03-01

    We have developed a detector to be used as monitor for proton therapy beam lines. The detector is a 2-D parallel plate ionization chamber, with the anode segmented in 1024 square pixels arranged in a 32×32 matrix. The detector characterization is presented.

  7. Optimizing Planning and Delivery of High-Precision Robotic Radiotherapy and Intensity-Modulated Proton Therapy

    NARCIS (Netherlands)

    S. van de Water (Steven)

    2015-01-01

    markdownabstract__Abstract__ High-precision robotic radiotherapy and intensity-modulated proton therapy (IMPT) are two relatively new radiotherapy techniques that particularly aim at a highly localized delivery of a curative dose to the tumor, while achieving excellent sparing of the surrounding

  8. Radiation Hardness of dSiPM Sensors in a Proton Therapy Radiation Environment

    NARCIS (Netherlands)

    Diblen, Faruk; Buitenhuis, Tom; Solf, Torsten; Rodrigues, Pedro; van der Graaf, Emiel; van Goethem, Marc-Jan; Brandenburg, Sytze; Dendooven, Peter

    2017-01-01

    In vivo verification of dose delivery in proton therapy by means of positron emission tomography (PET) or prompt gamma imaging is mostly based on fast scintillation detectors. The digital silicon photomultiplier (dSiPM) allows excellent scintillation detector timing properties and is thus being cons

  9. Development of a pixel ionization chamber for beam monitor in proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    La Rosa, A. [Dipartimento di Fisica Sperimentale, Universita di Torino, Via P. Giuria 1, Turin 10125 (Italy) and INFN, Sezione di Torino, Via P. Giuria, Turin 10125 (Italy)]. E-mail: larosa@to.infn.it; Garella, M.A. [INFN, Sezione di Torino, Via P. Giuria, Turin 10125 (Italy); Attili, A. [Dipartimento di Fisica Sperimentale, Universita di Torino, Via P. Giuria 1, Turin 10125 (Italy); Bourhaleb, F. [Fondazione TERA, Via Puccini 11, Novara 28100 (Italy); Cirio, R. [INFN, Sezione di Torino, Via P. Giuria, Turin 10125 (Italy); Donetti, M. [INFN, Sezione di Torino, Via P. Giuria, Turin 10125 (Italy); Fondazione CNAO, Via Caminadella 16, Milan 20123 (Italy); Giordanengo, S. [INFN, Sezione di Torino, Via P. Giuria, Turin 10125 (Italy); Givehchi, N. [Dipartimento di Fisica Sperimentale, Universita di Torino, Via P. Giuria 1, Turin 10125 (Italy); INFN, Sezione di Torino, Via P. Giuria, Turin 10125 (Italy); Marchetto, F. [INFN, Sezione di Torino, Via P. Giuria, Turin 10125 (Italy); Mazza, G. [INFN, Sezione di Torino, Via P. Giuria, Turin 10125 (Italy); Meyroneinc, S. [Institut Curie-Centre de Protontherapie de Orsay, Bat. 101 Campus Universitaire, Orsay Cedex 91898 (France); Pecka, A. [Dipartimento di Fisica Sperimentale, Universita di Torino, Via P. Giuria 1, Turin 10125 (Italy); Peroni, C. [Dipartimento di Fisica Sperimentale, Universita di Torino, Via P. Giuria 1, Turin 10125 (Italy); INFN, Sezione di Torino, Via P. Giuria, Turin 10125 (Italy); Pitta, G. [Fondazione TERA, Via Puccini 11, Novara 28100 (Italy)

    2007-03-01

    We have developed a detector to be used as monitor for proton therapy beam lines. The detector is a 2-D parallel plate ionization chamber, with the anode segmented in 1024 square pixels arranged in a 32x32 matrix. The detector characterization is presented.

  10. Pet imaging of dose distribution in proton-beam cancer therapy

    Directory of Open Access Journals (Sweden)

    Beebe-Wang Joanne

    2005-01-01

    Full Text Available Proton therapy is a treatment modality of increasing utility in clinical radiation oncology mostly because its dose distribution conforms more tightly to the target volume than X-ray radiation therapy. One important feature of proton therapy is that it produces a small amount of positron-emitting isotopes along the beam-path through the non-elastic nuclear interaction of protons with target nuclei such as 12C, 14N, and 16O. These radio isotopes, mainly 11C, 13N, and 15O, al low imaging the therapy dose distribution using positron emission tomography. The resulting positron emission tomography images provide a powerful tool for quality assurance of the treatment, especially when treating inhomogeneous organs such as the lungs or the head-and-neck, where the calculation of the dose distribution for treatment planning is more difficult. This pa per uses Monte Carlo simulations to predict the yield of positron emitters produced by a 250 MeV proton beam, and to simulate the productions of the image in a clinical PET scanner.

  11. Optimizing Planning and Delivery of High-Precision Robotic Radiotherapy and Intensity-Modulated Proton Therapy

    NARCIS (Netherlands)

    S. van de Water (Steven)

    2015-01-01

    markdownabstract__Abstract__ High-precision robotic radiotherapy and intensity-modulated proton therapy (IMPT) are two relatively new radiotherapy techniques that particularly aim at a highly localized delivery of a curative dose to the tumor, while achieving excellent sparing of the surrounding he

  12. Transarterial Fiducial Marker Placement for Image-guided Proton Therapy for Malignant Liver Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, Kengo, E-mail: yesterday.is.yesterday@gmail.com; Shimohira, Masashi, E-mail: mshimohira@gmail.com [Nagoya City University Graduate School of Medical Sciences, Department of Radiology (Japan); Sasaki, Shigeru, E-mail: ssasaki916@yahoo.co.jp; Iwata, Hiromitsu, E-mail: h-iwa-ncu@nifty.com; Nishikawa, Hiroko, E-mail: piroko1018@gmail.com; Ogino, Hiroyuki, E-mail: oginogio@gmail.com; Hara, Masaki, E-mail: mhara@med.nagoya-cu.ac.jp [Nagoya City West Medical Center, Department of Radiation Oncology, Nagoya Proton Therapy Center (Japan); Hashizume, Takuya, E-mail: tky300@gmail.com; Shibamoto, Yuta, E-mail: yshiba@med.nagoya-cu.ac.jp [Nagoya City University Graduate School of Medical Sciences, Department of Radiology (Japan)

    2015-10-15

    PurposeThe aim of this study is to analyze the technical and clinical success rates and safety of transarterial fiducial marker placement for image-guided proton therapy for malignant liver tumors.Methods and MaterialsFifty-five patients underwent this procedure as an interventional treatment. Five patients had 2 tumors, and 4 tumors required 2 markers each, so the total number of procedures was 64. The 60 tumors consisted of 46 hepatocellular carcinomas and 14 liver metastases. Five-mm-long straight microcoils of 0.018 inches in diameter were used as fiducial markers and placed in appropriate positions for each tumor. We assessed the technical and clinical success rates of transarterial fiducial marker placement, as well as the complications associated with it. Technical success was defined as the successful delivery and placement of the fiducial coil, and clinical success was defined as the completion of proton therapy.ResultsAll 64 fiducial coils were successfully installed, so the technical success rate was 100 % (64/64). Fifty-four patients underwent proton therapy without coil migration. In one patient, proton therapy was not performed because of obstructive jaundice due to bile duct invasion by hepatocellular carcinoma. Thus, the clinical success rate was 98 % (54/55). Slight bleeding was observed in one case, but it was stopped immediately and then observed. None of the patients developed hepatic infarctions due to fiducial marker migration.ConclusionTransarterial fiducial marker placement appears to be a useful and safe procedure for proton therapy for malignant liver tumors.

  13. Proton Therapy for Breast Cancer After Mastectomy: Early Outcomes of a Prospective Clinical Trial

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, Shannon M., E-mail: smacdonald@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (United States); Patel, Sagar A.; Hickey, Shea [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (United States); Specht, Michelle [Department of Surgical Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (United States); Isakoff, Steven J. [Division of Hematology and Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (United States); Gadd, Michele; Smith, Barbara L. [Department of Surgical Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (United States); Yeap, Beow Y. [Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (United States); Adams, Judith; DeLaney, Thomas F.; Kooy, Hanne; Lu, Hsiao-Ming; Taghian, Alphonse G. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (United States)

    2013-07-01

    Purpose: Dosimetric planning studies have described potential benefits for the use of proton radiation therapy (RT) for locally advanced breast cancer. We report acute toxicities and feasibility of proton delivery for 12 women treated with postmastectomy proton radiation with or without reconstruction. Methods and Materials: Twelve patients were enrolled in an institutional review board-approved prospective clinical trial. The patients were assessed for skin toxicity, fatigue, and radiation pneumonitis during treatment and at 4 and 8 weeks after the completion of therapy. All patients consented to have photographs taken for documentation of skin toxicity. Results: Eleven of 12 patients had left-sided breast cancer. One patient was treated for right-sided breast cancer with bilateral implants. Five women had permanent implants at the time of RT, and 7 did not have immediate reconstruction. All patients completed proton RT to a dose of 50.4 Gy (relative biological effectiveness [RBE]) to the chest wall and 45 to 50.4 Gy (RBE) to the regional lymphatics. No photon or electron component was used. The maximum skin toxicity during radiation was grade 2, according to the Common Terminology Criteria for Adverse Events (CTCAE). The maximum CTCAE fatigue was grade 3. There have been no cases of RT pneumonitis to date. Conclusions: Proton RT for postmastectomy RT is feasible and well tolerated. This treatment may be warranted for selected patients with unfavorable cardiac anatomy, immediate reconstruction, or both that otherwise limits optimal RT delivery using standard methods.

  14. The precision of respiratory-gated delivery of synchrotron-based pulsed beam proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Tsunashima, Yoshikazu; Vedam, Sastry; Dong Lei; Balter, Peter; Mohan, Radhe [Department of Radiation Physics, Unit 94, University of Texas M D Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 (United States); Umezawa, Masumi, E-mail: ytsunash@mdanderson.or [Accelerator System Group Medical System Project, Hitachi, Ltd, Energy and Environmental Systems Laboratory, 2-1, Omika-cho 7-chome, Hitachi-shi, Ibaraki-ken 319-1221 (Japan)

    2010-12-21

    A synchrotron-based proton therapy system operates in a low repetition rate pulsed beam delivery mode. Unlike cyclotron-based beam delivery, there is no guarantee that a synchrotron beam can be delivered effectively or precisely under the respiratory-gated mode. To evaluate the performance of gated synchrotron treatment, we simulated proton beam delivery in the synchrotron-based respiratory-gated mode using realistic patient breathing signals. Parameters used in the simulation were respiratory motion traces (70 traces from 24 patients), respiratory gate levels (10%, 20% and 30% duty cycles at the exhalation phase) and synchrotron magnet excitation cycles (T{sub cyc}) (fixed T{sub cyc} mode: 2.7, 3.0-6.0 s and each patient breathing cycle, and variable T{sub cyc} mode). The simulations were computed according to the breathing trace in which the proton beams were delivered. In the shorter fixed T{sub cyc} (<4 s), most of the proton beams were delivered uniformly to the target during the entire expiration phase of the respiratory cycle. In the longer fixed T{sub cyc} (>4 s) and the variable T{sub cyc} mode, the proton beams were not consistently delivered during the end-expiration phase of the respiratory cycle. However we found that the longer and variable T{sub cyc} operation modes delivered proton beams more precisely during irregular breathing.

  15. Range monitoring proton therapy by means of secondary radiation detection

    Energy Technology Data Exchange (ETDEWEB)

    Torres Espallardo, I.; Gillam, J. E.; Garcia Ortega, P.; Cabello, J.; Oliver, J.; Llosa, G.; Trovato, M.; Solaz, C.; Lacasta, C.; Rafecas, M.

    2013-07-01

    The goal of this work is to study the ability of the open ring PET geometries with TOF and of the proposed Compton Camera for assessing range shifts below 5 mm. All this work is part of the ENVISION project which is directed towards on-line dose monitoring in hadron therapy. (Author)

  16. The University of Texas M.D. Anderson Cancer Center Proton Therapy Facility

    Science.gov (United States)

    Smith, Alfred; Newhauser, Wayne; Latinkic, Mitchell; Hay, Amy; McMaken, Bruce; Styles, John; Cox, James

    2003-08-01

    The University of Texas M.D. Anderson Cancer Center (MDACC), in partnership with Sanders Morris Harris Inc., a Texas-based investment banking firm, and The Styles Company, a developer and manager of hospitals and healthcare facilities, is building a proton therapy facility near the MDACC main complex at the Texas Medical Center in Houston, Texas USA. The MDACC Proton Therapy Center will be a freestanding, investor-owned radiation oncology center offering state-of-the-art proton beam therapy. The facility will have four treatment rooms: three rooms will have rotating, isocentric gantries and the fourth treatment room will have capabilities for both large and small field (e.g. ocular melanoma) treatments using horizontal beam lines. There will be an additional horizontal beam room dedicated to physics research and development, radiation biology research, and outside users who wish to conduct experiments using proton beams. The first two gantries will each be initially equipped with a passive scattering nozzle while the third gantry will have a magnetically swept pencil beam scanning nozzle. The latter will include enhancements to the treatment control system that will allow for the delivery of proton intensity modulation treatments. The proton accelerator will be a 250 MeV zero-gradient synchrotron with a slow extraction system. The facility is expected to open for patient treatments in the autumn of 2005. It is anticipated that 675 patients will be treated during the first full year of operation, while full capacity, reached in the fifth year of operation, will be approximately 3,400 patients per year. Treatments will be given up to 2-shifts per day and 6 days per week.

  17. Proton Beam Therapy for Non-Small Cell Lung Cancer: Current Clinical Evidence and Future Directions

    Directory of Open Access Journals (Sweden)

    Abigail T. Berman

    2015-07-01

    Full Text Available Lung cancer is the leading cancer cause of death in the United States. Radiotherapy is an essential component of the definitive treatment of early-stage and locally-advanced lung cancer, and the palliative treatment of metastatic lung cancer. Proton beam therapy (PBT, through its characteristic Bragg peak, has the potential to decrease the toxicity of radiotherapy, and, subsequently improve the therapeutic ratio. Herein, we provide a primer on the physics of proton beam therapy for lung cancer, present the existing data in early-stage and locally-advanced non-small cell lung cancer (NSCLC, as well as in special situations such as re-irradiation and post-operative radiation therapy. We then present the technical challenges, such as anatomic changes and motion management, and future directions for PBT in lung cancer, including pencil beam scanning.

  18. The proton therapy nozzles at Samsung Medical Center: A Monte Carlo simulation study using TOPAS

    Science.gov (United States)

    Chung, Kwangzoo; Kim, Jinsung; Kim, Dae-Hyun; Ahn, Sunghwan; Han, Youngyih

    2015-07-01

    To expedite the commissioning process of the proton therapy system at Samsung Medical Center (SMC), we have developed a Monte Carlo simulation model of the proton therapy nozzles by using TOol for PArticle Simulation (TOPAS). At SMC proton therapy center, we have two gantry rooms with different types of nozzles: a multi-purpose nozzle and a dedicated scanning nozzle. Each nozzle has been modeled in detail following the geometry information provided by the manufacturer, Sumitomo Heavy Industries, Ltd. For this purpose, the novel features of TOPAS, such as the time feature or the ridge filter class, have been used, and the appropriate physics models for proton nozzle simulation have been defined. Dosimetric properties, like percent depth dose curve, spreadout Bragg peak (SOBP), and beam spot size, have been simulated and verified against measured beam data. Beyond the Monte Carlo nozzle modeling, we have developed an interface between TOPAS and the treatment planning system (TPS), RayStation. An exported radiotherapy (RT) plan from the TPS is interpreted by using an interface and is then translated into the TOPAS input text. The developed Monte Carlo nozzle model can be used to estimate the non-beam performance, such as the neutron background, of the nozzles. Furthermore, the nozzle model can be used to study the mechanical optimization of the design of the nozzle.

  19. The Proton Therapy Nozzles at Samsung Medical Center: A Monte Carlo Simulation Study using TOPAS

    CERN Document Server

    Chung, Kwangzoo; Kim, Dae-Hyun; Ahn, Sunghwan; Han, Youngyih

    2015-01-01

    To expedite the commissioning process of the proton therapy system at Samsung Medical Center (SMC), we have developed a Monte Carlo simulation model of the proton therapy nozzles using TOPAS. At SMC proton therapy center, we have two gantry rooms with different types of nozzles; a multi-purpose nozzle and a dedicated scanning nozzle. Each nozzle has been modeled in detail following the geometry information provided by the manufacturer, Sumitomo Heavy Industries, Ltd. For this purpose, novel features of TOPAS, such as the time feature or the ridge filter class, have been used. And the appropriate physics models for proton nozzle simulation were defined. Dosimetric properties, like percent depth dose curve, spread-out Bragg peak (SOBP), beam spot size, have been simulated and verified against measured beam data. Beyond the Monte Carlo nozzle modeling, we have developed an interface between TOPAS and the treatment planning system (TPS), RayStation. An exported RT plan data from the TPS has been interpreted by th...

  20. Intensity modulated radiation therapy using laser-accelerated protons: a Monte Carlo dosimetric study.

    Science.gov (United States)

    Fourkal, E; Li, J S; Xiong, W; Nahum, A; Ma, C M

    2003-12-21

    In this paper we present Monte Carlo studies of intensity modulated radiation therapy using laser-accelerated proton beams. Laser-accelerated protons coming out of a solid high-density target have broad energy and angular spectra leading to dose distributions that cannot be directly used for therapeutic applications. Through the introduction of a spectrometer-like particle selection system that delivers small pencil beams of protons with desired energy spectra it is feasible to use laser-accelerated protons for intensity modulated radiotherapy. The method presented in this paper is a three-dimensional modulation in which the proton energy spectrum and intensity of each individual beamlet are modulated to yield a homogeneous dose in both the longitudinal and lateral directions. As an evaluation of the efficacy of this method, it has been applied to two prostate cases using a variety of beam arrangements. We have performed a comparison study between intensity modulated photon plans and those for laser-accelerated protons. For identical beam arrangements and the same optimization parameters, proton plans exhibit superior coverage of the target and sparing of neighbouring critical structures. Dose-volume histogram analysis of the resulting dose distributions shows up to 50% reduction of dose to the critical structures. As the number of fields is decreased, the proton modality exhibits a better preservation of the optimization requirements on the target and critical structures. It is shown that for a two-beam arrangement (parallel-opposed) it is possible to achieve both superior target coverage with 5% dose inhomogeneity within the target and excellent sparing of surrounding tissue.

  1. GPU-based fast Monte Carlo dose calculation for proton therapy.

    Science.gov (United States)

    Jia, Xun; Schümann, Jan; Paganetti, Harald; Jiang, Steve B

    2012-12-07

    Accurate radiation dose calculation is essential for successful proton radiotherapy. Monte Carlo (MC) simulation is considered to be the most accurate method. However, the long computation time limits it from routine clinical applications. Recently, graphics processing units (GPUs) have been widely used to accelerate computationally intensive tasks in radiotherapy. We have developed a fast MC dose calculation package, gPMC, for proton dose calculation on a GPU. In gPMC, proton transport is modeled by the class II condensed history simulation scheme with a continuous slowing down approximation. Ionization, elastic and inelastic proton nucleus interactions are considered. Energy straggling and multiple scattering are modeled. Secondary electrons are not transported and their energies are locally deposited. After an inelastic nuclear interaction event, a variety of products are generated using an empirical model. Among them, charged nuclear fragments are terminated with energy locally deposited. Secondary protons are stored in a stack and transported after finishing transport of the primary protons, while secondary neutral particles are neglected. gPMC is implemented on the GPU under the CUDA platform. We have validated gPMC using the TOPAS/Geant4 MC code as the gold standard. For various cases including homogeneous and inhomogeneous phantoms as well as a patient case, good agreements between gPMC and TOPAS/Geant4 are observed. The gamma passing rate for the 2%/2 mm criterion is over 98.7% in the region with dose greater than 10% maximum dose in all cases, excluding low-density air regions. With gPMC it takes only 6-22 s to simulate 10 million source protons to achieve ∼1% relative statistical uncertainty, depending on the phantoms and energy. This is an extremely high efficiency compared to the computational time of tens of CPU hours for TOPAS/Geant4. Our fast GPU-based code can thus facilitate the routine use of MC dose calculation in proton therapy.

  2. Online monitoring for proton therapy: A real-time procedure using a planar PET system

    Energy Technology Data Exchange (ETDEWEB)

    Kraan, A.C. [Department of Physics, University of Pisa and INFN, Pisa (Italy); Battistoni, G. [INFN Sezione di Milano, Milano (Italy); Belcari, N.; Camarlinghi, N. [Department of Physics, University of Pisa and INFN, Pisa (Italy); Ciocca, M. [Fondazione CNAO, Pavia (Italy); Ferrari, A. [CERN, Geneva (Switzerland); Ferretti, S. [Department of Physics, University of Pisa and INFN, Pisa (Italy); Mairani, A.; Molinelli, S.; Pullia, M. [Fondazione CNAO, Pavia (Italy); Sala, P. [INFN Sezione di Milano, Milano (Italy); Sportelli, G.; Del Guerra, A. [Department of Physics, University of Pisa and INFN, Pisa (Italy); Rosso, V., E-mail: valeria.rosso@pi.infn.it [Department of Physics, University of Pisa and INFN, Pisa (Italy)

    2015-06-21

    In this study a procedure for range verification in proton therapy by means of a planar in-beam PET system is presented. The procedure consists of two steps: the measurement of the β{sup +}-activity induced in the irradiated body by the proton beam and the comparison of these distributions with simulations. The experimental data taking was performed at the CNAO center in Pavia, Italy, irradiating plastic phantoms. For two different cases we demonstrate how a real-time feedback of the delivered treatment plan can be obtained with in-beam PET imaging.

  3. Online monitoring for proton therapy: A real-time procedure using a planar PET system

    Science.gov (United States)

    Kraan, A. C.; Battistoni, G.; Belcari, N.; Camarlinghi, N.; Ciocca, M.; Ferrari, A.; Ferretti, S.; Mairani, A.; Molinelli, S.; Pullia, M.; Sala, P.; Sportelli, G.; Del Guerra, A.; Rosso, V.

    2015-06-01

    In this study a procedure for range verification in proton therapy by means of a planar in-beam PET system is presented. The procedure consists of two steps: the measurement of the β+-activity induced in the irradiated body by the proton beam and the comparison of these distributions with simulations. The experimental data taking was performed at the CNAO center in Pavia, Italy, irradiating plastic phantoms. For two different cases we demonstrate how a real-time feedback of the delivered treatment plan can be obtained with in-beam PET imaging.

  4. Online monitoring for proton therapy: A real-time procedure using a planar PET system

    CERN Document Server

    Kraan, A C; Belcari, N; Camarlinghi, N; Ciocca, M; Ferrari, A; Ferretti, S; Mairani, A; Molinelli, S; Pullia, M; Sala, P; Sportelli, G; Del Guerra, A; Rosso, V

    2015-01-01

    In this study a procedure for range verification in proton therapy by means of a planar in-beam PET system is presented. The procedure consists of two steps: the measurement of the β+-activity induced in the irradiated body by the proton beam and the comparison of these distributions with simulations. The experimental data taking was performed at the CNAO center in Pavia, Italy, irradiating plastic phantoms. For two different cases we demonstrate how a real-time feedback of the delivered treatment plan can be obtained with in-beam PET imaging.

  5. SU-E-T-764: Track Repeating Algorithm for Proton Therapy Applied to Intensity Modulated Proton Therapy for Head-And-Neck Patients

    Energy Technology Data Exchange (ETDEWEB)

    Yepes, P [Rice University, Houston, TX 77005 (United States); Mirkovic, D [U.T M.D. Anderson Cancer Center, Houston, TX (United States); Mohan, R [UT MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: To determine the suitability of fast Monte Carlo techniques for dose calculation in particle therapy based on track-repeating algorithm for Intensity Modulated Proton Therapy, IMPT. The application of this technique will make possible detailed retrospective studies of large cohort of patients, which may lead to a better determination of Relative Biological Effects from the analysis of patient data. Methods: A cohort of six head-and-neck patients treated at the University of Texas MD Anderson Cancer Center with IMPT were utilized. The dose distributions were calculated with the standard Treatment Plan System, TPS, MCNPX, GEANT4 and FDC, a fast track-repeating algorithm for proton therapy for the verification and the patient plans. FDC is based on a GEANT4 database of trajectories of protons in a water. The obtained dose distributions were compared to each other utilizing the g-index criteria for 3mm-3% and 2mm-2%, for the maximum spatial and dose differences. The γ-index was calculated for voxels with a dose at least 10% of the maximum delivered dose. Dose Volume Histograms are also calculated for the various dose distributions. Results: Good agreement between GEANT4 and FDC is found with less than 1% of the voxels with a γ-index larger than 1 for 2 mm-2%. The agreement between MCNPX with FDC is within the requirements of clinical standards, even though it is slightly worse than the comparison with GEANT4.The comparison with TPS yielded larger differences, what is also to be expected because pencil beam algorithm do not always performed well in highly inhomogeneous areas like head-and-neck. Conclusion: The good agreement between a track-repeating algorithm and a full Monte Carlo for a large cohort of patients and a challenging, site like head-and-neck, opens the path to systematic and detailed studies of large cohorts, which may yield better understanding of biological effects.

  6. Towards the development of a direct electrochemical biodetector of avidin based on the poly(chloro amino β-styryl terthiophene)-coated glassy carbon electrode

    KAUST Repository

    Mehenni, Hakim

    2012-03-30

    In this study, a simple and direct biodetector was proposed, which was based on biotin immobilized onto a conducting polymer-coated electrode, for the detection of avidin, a highly stable glycoprotein found in egg-whites. Biotin was immobilized onto the electrode by covalent coupling to the primary amine group on the poly 3′-(3-chloro-4-amino-β-styryl)-(2,2′: 5′,2″-terthiophene) (PCAST), and the biotinavidin interaction was monitored by cyclic voltammetry. Incubation of the PCAST/biotin-modified-coated electrode with avidin in a phosphate buffered saline solution caused a significant change to its cyclic voltammogram, which was explained by the binding of avidin by biotin, and resulted in restricted ion transfer to and from the conducting polymer. This change was then utilized to detect avidin at 4 × 10 -6molL -1. © 2012 CSIRO.

  7. Methods for reducing patient radiation exposure during proton therapy for eye disease

    Directory of Open Access Journals (Sweden)

    Victor A. Bakaev

    2017-06-01

    Full Text Available The paper is dedicated to techniques for reduction of background radiation in the room for conducting proton eye radiotherapy. The necessity of this reduction stems from the health risk of low-dose effect on the personnel and patients. We have touched the aspects of background reduction both at the cost of secondary particles, produced in beam-forming systems, and the dose reduction for the patient's healthy tissue (when carrying out beam therapy owing to correct assessment of the biological effects of protons with energies up to 60MeV. The obtained calculation results prove that an increase in the proton beam diameter provides the possibility of reducing the background radiation by more than a factor of three in the room and of correspondingly decreasing the body's radiation exposure. It is necessary to take correct account of RBE to reduce the radiation exposure of adjacent organs.

  8. Liquid fiducial marker applicability in proton therapy of locally advanced lung cancer

    DEFF Research Database (Denmark)

    Scherman Rydhög, Jonas; Perrin, Rosalind; Jølck, Rasmus Irming

    2017-01-01

    .164 for the LFM. Phantom measurements revealed a maximum relative deviation in dose of 4.8% for the LFM in the spread-out Bragg Peak, compared to 12-67% for the solid markers. Using the experimentally determined RSP, the maximum proton range error introduced by the LFM is about 1. mm. If the marker was displaced......Background and purpose: We investigated the clinical applicability of a novel liquid fiducial marker (LFM) for image-guided pencil beam scanned (PBS) proton therapy (PBSPT) of locally advanced lung cancer (LALC). Materials and methods: The relative proton stopping power (RSP) of the LFM...... was calculated and measured. Dose perturbations of the LFM and three solid markers, in a phantom, were measured. PBSPT treatment planning on computer tomography scans of five patients with LALC with the LFM implanted was performed with 1-3 fields. Results: The RSP was experimentally determined to be 1...

  9. Validation of dosimetric field matching accuracy from proton therapy using a robotic patient positioning system.

    Science.gov (United States)

    Farr, Jonathan B; O'Ryan-Blair, Avril; Jesseph, Frederick; Hsi, Wen-Chien; Allgower, Chris E; Mascia, Anthony E; Thornton, Allan F; Schreuder, Andreas N

    2010-04-12

    Large area, shallow fields are well suited to proton therapy. However, due to beam production limitations, such volumes typically require multiple matched fields. This is problematic due to the relatively narrow beam penumbra at shallow depths compared to electron and photon beams. Therefore, highly accurate dose planning and delivery is required. As the dose delivery includes shifting the patient for matched fields, accuracy at the 1-2 millimeter level in patient positioning is also required. This study investigates the dosimetric accuracy of such proton field matching by an innovative robotic patient positioner system (RPPS). The dosimetric comparisons were made between treatment planning system calculations, radiographic film and ionization chamber measurements. The results indicated good agreement amongst the methods and suggest that proton field matching by a RPPS is accurate and efficient.

  10. Shortening Delivery Times of Intensity Modulated Proton Therapy by Reducing Proton Energy Layers During Treatment Plan Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Water, Steven van de, E-mail: s.vandewater@erasmusmc.nl [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam (Netherlands); Kooy, Hanne M. [F. H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Heijmen, Ben J.M.; Hoogeman, Mischa S. [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam (Netherlands)

    2015-06-01

    Purpose: To shorten delivery times of intensity modulated proton therapy by reducing the number of energy layers in the treatment plan. Methods and Materials: We have developed an energy layer reduction method, which was implemented into our in-house-developed multicriteria treatment planning system “Erasmus-iCycle.” The method consisted of 2 components: (1) minimizing the logarithm of the total spot weight per energy layer; and (2) iteratively excluding low-weighted energy layers. The method was benchmarked by comparing a robust “time-efficient plan” (with energy layer reduction) with a robust “standard clinical plan” (without energy layer reduction) for 5 oropharyngeal cases and 5 prostate cases. Both plans of each patient had equal robust plan quality, because the worst-case dose parameters of the standard clinical plan were used as dose constraints for the time-efficient plan. Worst-case robust optimization was performed, accounting for setup errors of 3 mm and range errors of 3% + 1 mm. We evaluated the number of energy layers and the expected delivery time per fraction, assuming 30 seconds per beam direction, 10 ms per spot, and 400 Giga-protons per minute. The energy switching time was varied from 0.1 to 5 seconds. Results: The number of energy layers was on average reduced by 45% (range, 30%-56%) for the oropharyngeal cases and by 28% (range, 25%-32%) for the prostate cases. When assuming 1, 2, or 5 seconds energy switching time, the average delivery time was shortened from 3.9 to 3.0 minutes (25%), 6.0 to 4.2 minutes (32%), or 12.3 to 7.7 minutes (38%) for the oropharyngeal cases, and from 3.4 to 2.9 minutes (16%), 5.2 to 4.2 minutes (20%), or 10.6 to 8.0 minutes (24%) for the prostate cases. Conclusions: Delivery times of intensity modulated proton therapy can be reduced substantially without compromising robust plan quality. Shorter delivery times are likely to reduce treatment uncertainties and costs.

  11. Beam-on imaging of short-lived positron emitters during proton therapy

    Science.gov (United States)

    Buitenhuis, H. J. T.; Diblen, F.; Brzezinski, K. W.; Brandenburg, S.; Dendooven, P.

    2017-06-01

    In vivo dose delivery verification in proton therapy can be performed by positron emission tomography (PET) of the positron-emitting nuclei produced by the proton beam in the patient. A PET scanner installed in the treatment position of a proton therapy facility that takes data with the beam on will see very short-lived nuclides as well as longer-lived nuclides. The most important short-lived nuclide for proton therapy is 12N (Dendooven et al 2015 Phys. Med. Biol. 60 8923-47), which has a half-life of 11 ms. The results of a proof-of-principle experiment of beam-on PET imaging of short-lived 12N nuclei are presented. The Philips Digital Photon Counting Module TEK PET system was used, which is based on LYSO scintillators mounted on digital SiPM photosensors. A 90 MeV proton beam from the cyclotron at KVI-CART was used to investigate the energy and time spectra of PET coincidences during beam-on. Events coinciding with proton bunches, such as prompt gamma rays, were removed from the data via an anti-coincidence filter with the cyclotron RF. The resulting energy spectrum allowed good identification of the 511 keV PET counts during beam-on. A method was developed to subtract the long-lived background from the 12N image by introducing a beam-off period into the cyclotron beam time structure. We measured 2D images and 1D profiles of the 12N distribution. A range shift of 5 mm was measured as 6  ±  3 mm using the 12N profile. A larger, more efficient, PET system with a higher data throughput capability will allow beam-on 12N PET imaging of single spots in the distal layer of an irradiation with an increased signal-to-background ratio and thus better accuracy. A simulation shows that a large dual panel scanner, which images a single spot directly after it is delivered, can measure a 5 mm range shift with millimeter accuracy: 5.5  ±  1.1 mm for 1  ×  108 protons and 5.2  ±  0.5 mm for 5  ×  108 protons. This makes

  12. Neutrons in active proton therapy. Parameterization of dose and dose equivalent

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Uwe; Haelg, Roger A. [Univ. of Zurich (Switzerland). Dept. of Physics; Radiotherapy Hirslanden AG, Aarau (Switzerland); Lomax, Tony [Paul Scherrer Institute, Villigen (Switzerland). Center for Proton Therapy

    2017-08-01

    One of the essential elements of an epidemiological study to decide if proton therapy may be associated with increased or decreased subsequent malignancies compared to photon therapy is an ability to estimate all doses to non-target tissues, including neutron dose. This work therefore aims to predict for patients using proton pencil beam scanning the spatially localized neutron doses and dose equivalents. The proton pencil beam of Gantry 1 at the Paul Scherrer Institute (PSI) was Monte Carlo simulated using GEANT. Based on the simulated neutron dose and neutron spectra an analytical mechanistic dose model was developed. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed model in order to calculate the neutron component of the delivered dose distribution for each treated patient. The neutron dose was estimated for two patient example cases. The analytical neutron dose model represents the three-dimensional Monte Carlo simulated dose distribution up to 85 cm from the proton pencil beam with a satisfying precision. The root mean square error between Monte Carlo simulation and model is largest for 138 MeV protons and is 19% and 20% for dose and dose equivalent, respectively. The model was successfully integrated into the PSI treatment planning system. In average the neutron dose is increased by 10% or 65% when using 160 MeV or 177 MeV instead of 138 MeV. For the neutron dose equivalent the increase is 8% and 57%. The presented neutron dose calculations allow for estimates of dose that can be used in subsequent epidemiological studies or, should the need arise, to estimate the neutron dose at any point where a subsequent secondary tumour may occur. It was found that the neutron dose to the patient is heavily increased with proton energy.

  13. Prompt gamma ray imaging for verification of proton boron fusion therapy: A Monte Carlo study.

    Science.gov (United States)

    Shin, Han-Back; Yoon, Do-Kun; Jung, Joo-Young; Kim, Moo-Sub; Suh, Tae Suk

    2016-10-01

    The purpose of this study was to verify acquisition feasibility of a single photon emission computed tomography image using prompt gamma rays for proton boron fusion therapy (PBFT) and to confirm an enhanced therapeutic effect of PBFT by comparison with conventional proton therapy without use of boron. Monte Carlo simulation was performed to acquire reconstructed image during PBFT. We acquired percentage depth dose (PDD) of the proton beams in a water phantom, energy spectrum of the prompt gamma rays, and tomographic images, including the boron uptake region (BUR; target). The prompt gamma ray image was reconstructed using maximum likelihood expectation maximisation (MLEM) with 64 projection raw data. To verify the reconstructed image, both an image profile and contrast analysis according to the iteration number were conducted. In addition, the physical distance between two BURs in the region of interest of each BUR was measured. The PDD of the proton beam from the water phantom including the BURs shows more efficient than that of conventional proton therapy on tumour region. A 719keV prompt gamma ray peak was clearly observed in the prompt gamma ray energy spectrum. The prompt gamma ray image was reconstructed successfully using 64 projections. Different image profiles including two BURs were acquired from the reconstructed image according to the iteration number. We confirmed successful acquisition of a prompt gamma ray image during PBFT. In addition, the quantitative image analysis results showed relatively good performance for further study. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  14. A dosimetric comparison of proton and photon therapy in unresectable cancers of the head of pancreas

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Reid F.; Zhai, Huifang; Both, Stefan; Metz, James M.; Plastaras, John P.; Ben-Josef, Edgar, E-mail: Edgar.Ben-Josef@uphs.upenn.edu [University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Mayekar, Sonal U. [Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States); Apisarnthanarax, Smith [University of Washington, Seattle, Washington 98109 (United States)

    2014-08-15

    Purpose: Uncontrolled local growth is the cause of death in ∼30% of patients with unresectable pancreatic cancers. The addition of standard-dose radiotherapy to gemcitabine has been shown to confer a modest survival benefit in this population. Radiation dose escalation with three-dimensional planning is not feasible, but high-dose intensity-modulated radiation therapy (IMRT) has been shown to improve local control. Still, dose-escalation remains limited by gastrointestinal toxicity. In this study, the authors investigate the potential use of double scattering (DS) and pencil beam scanning (PBS) proton therapy in limiting dose to critical organs at risk. Methods: The authors compared DS, PBS, and IMRT plans in 13 patients with unresectable cancer of the pancreatic head, paying particular attention to duodenum, small intestine, stomach, liver, kidney, and cord constraints in addition to target volume coverage. All plans were calculated to 5500 cGy in 25 fractions with equivalent constraints and normalized to prescription dose. All statistics were by two-tailed paired t-test. Results: Both DS and PBS decreased stomach, duodenum, and small bowel dose in low-dose regions compared to IMRT (p < 0.01). However, protons yielded increased doses in the mid to high dose regions (e.g., 23.6–53.8 and 34.9–52.4 Gy for duodenum using DS and PBS, respectively; p < 0.05). Protons also increased generalized equivalent uniform dose to duodenum and stomach, however these differences were small (<5% and 10%, respectively; p < 0.01). Doses to other organs-at-risk were within institutional constraints and placed no obvious limitations on treatment planning. Conclusions: Proton therapy does not appear to reduce OAR volumes receiving high dose. Protons are able to reduce the treated volume receiving low-intermediate doses, however the clinical significance of this remains to be determined in future investigations.

  15. SU-E-T-455: Characterization of 3D Printed Materials for Proton Beam Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zou, W; Siderits, R; McKenna, M; Khan, A; Yue, N [Rutgers University, New Brunswick, NJ (United States); McDonough, J; Yin, L; Teo, B [University of Pennsylvania, Philadelphia, PA (United States); Fisher, T [Memorial Medical Center, Modesto, CA (United States)

    2014-06-01

    Purpose: The widespread availability of low cost 3D printing technologies provides an alternative fabrication method for customized proton range modifying accessories such as compensators and boluses. However the material properties of the printed object are dependent on the printing technology used. In order to facilitate the application of 3D printing in proton therapy, this study investigated the stopping power of several printed materials using both proton pencil beam measurements and Monte Carlo simulations. Methods: Five 3–4 cm cubes fabricated using three 3D printing technologies (selective laser sintering, fused-deposition modeling and stereolithography) from five printers were investigated. The cubes were scanned on a CT scanner and the depth dose curves for a mono-energetic pencil beam passing through the material were measured using a large parallel plate ion chamber in a water tank. Each cube was measured from two directions (perpendicular and parallel to printing plane) to evaluate the effects of the anisotropic material layout. The results were compared with GEANT4 Monte Carlo simulation using the manufacturer specified material density and chemical composition data. Results: Compared with water, the differences from the range pull back by the printed blocks varied and corresponded well with the material CT Hounsfield unit. The measurement results were in agreement with Monte Carlo simulation. However, depending on the technology, inhomogeneity existed in the printed cubes evidenced from CT images. The effect of such inhomogeneity on the proton beam is to be investigated. Conclusion: Printed blocks by three different 3D printing technologies were characterized for proton beam with measurements and Monte Carlo simulation. The effects of the printing technologies in proton range and stopping power were studied. The derived results can be applied when specific devices are used in proton radiotherapy.

  16. Deep-penetration calculations in concrete and iron for shielding of proton therapy accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Sheu, Rong-Jiun, E-mail: rjsheu@mx.nthu.edu.tw [Institute of Nuclear Engineering and Science, National Tsing Hua University, 101 Sec. 2, Kung Fu Road, Hsinchu 300, Taiwan (China); Department of Engineering and System Science, National Tsing Hua University, 101 Sec. 2, Kung Fu Road, Hsinchu 300, Taiwan (China); National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 300, Taiwan (China); Chen, Yen-Fu [Department of Engineering and System Science, National Tsing Hua University, 101 Sec. 2, Kung Fu Road, Hsinchu 300, Taiwan (China); Lin, Uei-Tyng [Institute of Radiological Sciences, Tzu Chi College of Technology, 880 Sec. 2, Chien-Kuo Road, Hualien 970, Taiwan (China); Jiang, Shiang-Huei [Institute of Nuclear Engineering and Science, National Tsing Hua University, 101 Sec. 2, Kung Fu Road, Hsinchu 300, Taiwan (China); Department of Engineering and System Science, National Tsing Hua University, 101 Sec. 2, Kung Fu Road, Hsinchu 300, Taiwan (China)

    2012-06-01

    Proton accelerators in the energy range of approximately 200 MeV have become increasingly popular for cancer treatment in recent years. These proton therapy facilities usually involve bulky concrete or iron in their shielding design or accelerator structure. Simple shielding data, such as source terms or attenuation lengths for various proton energies and materials are useful in designing accelerator shielding. Understanding the appropriateness or uncertainties associated with these data, which are largely generated from Monte Carlo simulations, is critical to the quality of a shielding design. This study demonstrated and investigated the problems of deep-penetration calculations on the estimation of shielding parameters through an extensive comparison between the FLUKA and MCNPX calculations for shielding against a 200-MeV proton beam hitting an iron target. Simulations of double-differential neutron production from proton bombardment were validated by comparison with experimental data. For the concrete shielding, the FLUKA calculated depth-dose distributions were consistent with the MCNPX results, except for some discrepancies in backward directions. However, for the iron shielding, if FLUKA is used inappropriately then overestimation of neutron attenuation can be expected as shown by this work because of the multigroup treatment for low-energy neutrons in FLUKA. Two neutron energy group structures, three degrees of self-shielding correction, and two iron compositions were considered in this study. Significant variation of the resulting attenuation lengths indicated the importance of problem-dependent multigroup cross sections and proper modeling of iron composition in deep-penetration calculations.

  17. Design, construction and tests of a 3 GHz proton linac booster (LIBO) for cancer therapy

    Science.gov (United States)

    Berra, Paolo

    2007-12-01

    In the last ten years the use of proton beams in radiation therapy has become a clinical tool for treatment of deep-seated tumours. LIBO is a RF compact and low cost proton linear accelerator (SCL type) for hadrontherapy. It is conceived by TERA Foundation as a 3 GHz Linac Booster, to be mounted downstream of an existing cyclotron in order to boost the energy of the proton beam up to 200 MeV, needed for deep treatment (~25 cm) in the human body. With this solution it is possible to transform a low energy commercial cyclotron, normally used for eye melanoma therapy, isotope production and nuclear physics research, into an accelerator for deep-seated tumours. A prototype module of LIBO has been built and successfully tested with full RF power at CERN and with proton beam at INFN Laboratori Nazionali del Sud (LNS) in Catania, within an international collaboration between TERA Foundation, CERN, the Universities and INFN groups of Milan and Naples. The mid-term aim of the project is the technology transfer of the accumulated know-how to a consortium of companies and to bring this novel medical tool to hospitals. The design, construction and tests of the LIBO prototype are described in detail.

  18. The Role of Hypofractionated Radiation Therapy with Photons, Protons and Heavy Ions for Treating Extracranial Lesions

    Directory of Open Access Journals (Sweden)

    Aaron Michael Laine

    2016-01-01

    Full Text Available Traditionally, the ability to deliver large doses of ionizing radiation to a tumor has been limited by radiation induced toxicity to normal surrounding tissues. This was the initial impetus for the development of conventionally fractionated radiation therapy, where large volumes of healthy tissue received radiation and were allowed the time to repair the radiation damage. However, advances in radiation delivery techniques and image guidance have allowed for more ablative doses of radiation to be delivered in a very accurate, conformal and safe manner with shortened fractionation schemes. Hypofractionated regimens with photons have already transformed how certain tumor types are treated with radiation therapy. Additionally, hypofractionation is able to deliver a complete course of ablative radiation therapy over a shorter period of time compared to conventional fractionation regimens making treatment more convenient to the patient and potentially more cost-effective. Recently there has been an increased interest in proton therapy because of the potential further improvement in dose distributions achievable due to their unique physical characteristics. Furthermore, with heavier ions the dose conformality is increased and in addition there is potentially a higher biological effectiveness compared to protons and photons. Due to the properties mentioned above, charged particle therapy has already become an attractive modality to further investigate the role of hypofractionation in the treatment of various tumors. This review will discuss the rationale and evolution of hypofractionated radiation therapy, the reported clinical success with initially photon and then charged particle modalities, and further potential implementation into treatment regimens going forward.

  19. Noise evaluation of Compton camera imaging for proton therapy

    CERN Document Server

    Ortega, P G; Cerutti, F; Ferrari, A; Gillam, J E; Lacasta, C; Llosá, G; Oliver, J F; Sala, P R; Solevi, P; Rafecas, M

    2015-01-01

    Compton Cameras emerged as an alternative for real-time dose monitoring techniques for Particle Therapy (PT), based on the detection of prompt-gammas. As a consequence of the Compton scattering process, the gamma origin point can be restricted onto the surface of a cone (Compton cone). Through image reconstruction techniques, the distribution of the gamma emitters can be estimated, using cone-surfaces backprojections of the Compton cones through the image space, along with more sophisticated statistical methods to improve the image quality. To calculate the Compton cone required for image reconstruction, either two interactions, the last being photoelectric absorption, or three scatter interactions are needed. Because of the high energy of the photons in PT the first option might not be adequate, as the photon is not absorbed in general. However, the second option is less efficient. That is the reason to resort to spectral reconstructions, where the incoming γ energy is considered as a variable in the recons...

  20. The potential of proton beam radiation therapy in intracranial and ocular tumours

    Energy Technology Data Exchange (ETDEWEB)

    Blomquist, Erik [Univ. Hospital, Uppsala (Sweden). Dept. of Oncology, Radiology and Clinical Immunology; Bjelkengren, Goeran [Univ. Hospital, Malmoe (Sweden). Dept. of Oncology; Glimelius, Bengt [Karolinska Inst., Stockholm (Sweden). Dept. of Oncology and Pathology; Akademiska sjukhuset, Uppsala (Sweden). Dept. of Oncology, Radiology and Clinical Immunology

    2005-12-01

    A group of oncologists and hospital physicists have estimated the number of patients in Sweden suitable for proton beam therapy. The estimations have been based on current statistics of tumour incidence, number of patients potentially eligible for radiation treatment, scientific support from clinical trials and model dose planning studies and knowledge of the dose-response relations of different tumours and normal tissues. In intracranial benign and malignant tumours, it is estimated that between 130 and 180 patients each year are candidates for proton beam therapy. Of these, between 50 and 75 patients have malignant glioma, 30-40 meningeoma, 20-25 arteriovenous malformations, 20-25 skull base tumours and 10-15 pituitary adenoma. In addition, 15 patients with ocular melanoma are candidates.

  1. Investigation of Beam Dynamics in the Superconducting Synchrocyclotron for Proton Therapy

    Institute of Scientific and Technical Information of China (English)

    LI; Ming; ZHANG; Tian-jue

    2013-01-01

    With development of the superconducting technology,synchrocyclotron can be made very small through extreme high field,the structure of which is simple.So the synchrocyclotron is very suitable to be installed in the hospital for proton therapy.CIAE planned to build a 230 MeV superconducting synchrocyclotron,which is listed in the project of"Dragon 2020"and the key technology study is an

  2. A single-field integrated boost treatment planning technique for spot scanning proton therapy

    OpenAIRE

    Zhu, Xiaorong Ronald; Poenisch, Falk; LI, Heng; Zhang, Xiaodong; Sahoo, Narayan; Richard Y. Wu; Li, Xiaoqiang; Lee, Andrew K.; Chang, Eric L.; Choi, Seungtaek; Pugh, Thomas; Steven J. Frank; Gillin, Michael T.; Mahajan, Anita; Grosshans, David R.

    2014-01-01

    Purpose Intensity modulated proton therapy (IMPT) plans are normally generated utilizing multiple field optimization (MFO) techniques. Similar to photon based IMRT, MFO allows for the utilization of a simultaneous integrated boost in which multiple target volumes are treated to discrete doses simultaneously, potentially improving plan quality and streamlining quality assurance and treatment delivery. However, MFO may render plans more sensitive to the physical uncertainties inherent to partic...

  3. A method for selection of beam angles robust to intra-fractional motion in proton therapy of lung cancer

    DEFF Research Database (Denmark)

    Casares-Magaz, Oscar; Toftegaard, Jakob; Muren, Ludvig P.;

    2014-01-01

    Background. Proton therapy offers the potential for sparing the normal tissue surrounding the target. However, due to well-defined proton ranges around the Bragg peak, dose deposition is more sensitive to changes in the water equivalent path length (WEPL) than with photons. In this study, we assess...

  4. Strategic level proton therapy patient admission planning: a Markov decision process modeling approach.

    Science.gov (United States)

    Gedik, Ridvan; Zhang, Shengfan; Rainwater, Chase

    2016-01-25

    A relatively new consideration in proton therapy planning is the requirement that the mix of patients treated from different categories satisfy desired mix percentages. Deviations from these percentages and their impacts on operational capabilities are of particular interest to healthcare planners. In this study, we investigate intelligent ways of admitting patients to a proton therapy facility that maximize the total expected number of treatment sessions (fractions) delivered to patients in a planning period with stochastic patient arrivals and penalize the deviation from the patient mix restrictions. We propose a Markov Decision Process (MDP) model that provides very useful insights in determining the best patient admission policies in the case of an unexpected opening in the facility (i.e., no-shows, appointment cancellations, etc.). In order to overcome the curse of dimensionality for larger and more realistic instances, we propose an aggregate MDP model that is able to approximate optimal patient admission policies using the worded weight aggregation technique. Our models are applicable to healthcare treatment facilities throughout the United States, but are motivated by collaboration with the University of Florida Proton Therapy Institute (UFPTI).

  5. Compact Dielectric Wall Accelerator Development For Intensity Modulated Proton Therapy And Homeland Security Applications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y -; Caporaso, G J; Guethlein, G; Sampayan, S; Akana, G; Anaya, R; Blackfield, D; Cook, E; Falabella, S; Gower, E; Harris, J; Hawkins, S; Hickman, B; Holmes, C; Horner, A; Nelson, S; Paul, A; Pearson, D; Poole, B; Richardson, R; Sanders, D; Stanley, J; Sullivan, J; Wang, L; Watson, J; Weir, J

    2009-06-17

    Compact dielectric wall (DWA) accelerator technology is being developed at the Lawrence Livermore National Laboratory. The DWA accelerator uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. Its high electric field gradients are achieved by the use of alternating insulators and conductors and short pulse times. The DWA concept can be applied to accelerate charge particle beams with any charge to mass ratio and energy. Based on the DWA system, a novel compact proton therapy accelerator is being developed. This proton therapy system will produce individual pulses that can be varied in intensity, energy and spot width. The system will be capable of being sited in a conventional linac vault and provide intensity modulated rotational therapy. The status of the developmental new technologies that make the compact system possible will be reviewed. These include, high gradient vacuum insulators, solid dielectric materials, SiC photoconductive switches and compact proton sources. Applications of the DWA accelerator to problems in homeland security will also be discussed.

  6. Experimental validation of the filtering approach for dose monitoring in proton therapy at low energy.

    Science.gov (United States)

    Attanasi, F; Belcari, N; Camarda, M; Del Guerra, A; Moehrs, S; Rosso, V; Vecchio, S; Lanconelli, N; Cirrone, G A P; Di Rosa, F; Russo, G

    2008-06-01

    The higher physical selectivity of proton therapy demands higher accuracy in monitoring of the delivered dose, especially when the target volume is located next to critical organs and a fractionated therapy is applied. A method to verify a treatment plan and to ensure the high quality of the hadrontherapy is to use Positron Emission Tomography (PET), which takes advantage of the nuclear reactions between protons and nuclei in the tissue during irradiation producing beta(+)-emitting isotopes. Unfortunately, the PET image is not directly proportional to the delivered radiation dose distribution; this is the reason why, at the present time, the verification of depth dose profiles with PET techniques is limited to a comparison between the measured activity and the one predicted for the planned treatment by a Monte Carlo model. In this paper we test the feasibility of a different scheme, which permits to reconstruct the expected PET signal from the planned radiation dose distribution along beam direction in a simpler and more direct way. The considered filter model, based on the description of the PET image as a convolution of the dose distribution with a filter function, has already demonstrated its potential applicability to beam energies above 70 MeV. Our experimental investigation provides support to the possibility of extending the same approach to the lower energy range ([40, 70] MeV), in the perspective of its clinical application in eye proton therapy.

  7. Proton radiation therapy for chordomas and chondrosarcomas of the skull base.

    Science.gov (United States)

    Hug, E B; Slater, J D

    2000-10-01

    Most patients with conventional radiotherapy after surgery die with local disease progression. The superior local tumor control and overall survival achieved with fractionated proton RT can be attributed to improved dose localization characteristics of protons, resulting in higher doses delivered. Patients with base of skull neoplasms are increasingly considered for stereotactic radiosurgery. Recently, Muthukumar et al reported for the University of Pittsburgh group on cobalt-60 Gamma Knife (Elekta Instruments, Atlanta, GA) therapy for 15 patients with chordomas or chondrosarcomas of the base of the skull. With tumor volumes ranging between 0.98 and 10.3 mL (mean, 4.6 mL), doses to the tumor margin varying from 12 to 20 Gy (median, 18 Gy) were delivered. Two patients were treated without histologic tumor confirmation. After a median follow-up time of 40 months, 2 patients had died of disease, 2 patients had succumbed to intercurrent disease, and 1 patient surviving at the time of analysis had developed tumor progression. Neither actuarial local control nor actuarial survival data were presented. In the LLUMC series, most tumors exceeded sizes reportedly suitable for radiosurgery or were of a highly irregular configuration. Nevertheless, in 11 patients, tumors less than 15 mL in size remained locally controlled as did tumors sized between 15 and 25 mL in 11 additional patients; these patients were thus potential candidates for stereotactic radiosurgery. At present, too few reports on radiosurgery contain sufficient patient numbers and statistical analyses to permit one to draw conclusions about the feasibility of radiosurgery for chordomas and chondrosarcomas of the base of the skull. A principal difference between proton RT and radiosurgery as currently practiced in most centers concerns target definition. In proton RT, the GTV is treated. In addition, a clinical volume is defined, which is distinctly different from the GTV in size and shape, to include the

  8. Protective effect of transparent film dressing on proton therapy induced skin reactions

    Directory of Open Access Journals (Sweden)

    Whaley Jonathan T

    2013-01-01

    Full Text Available Abstract Objective Proton therapy can result in clinically significant radiation dermatitis. In some clinical scenarios, such as lung or breast cancer, the risk of severe radiation dermatitis may limit beam arrangement and prescription doses. Patients undergoing proton therapy for prostate cancer commonly develop mild radiation dermatitis. Herein, we report the outcomes of two prostate cancer patients whose radiation dermatitis appears to have been substantially diminished by transparent film dressings (Beekley stickers. Methods This is a descriptive report of the skin toxicity observed in two patients undergoing proton therapy for prostate cancer at a single institution in 2011. A phantom dosimetric study was performed to evaluate the impact of a transparent film dressing on a beam’s spread out Bragg peak (SOBP. Results Two patients with low risk prostate cancer were treated with proton therapy to a total dose of 79.2Gy (RBE in 1.8 Gy (RBE fractions using two opposed lateral beams daily. Both patients had small circular (2.5 cm diameter transparent adhesive markers placed on their skin to assist with daily alignment. Patient 1 had markers in place bilaterally for the entirety of treatment. Patient 2 had a marker in place for three weeks on one side and six weeks on the other. Over the course of therapy, both men developed typical Grade 1 radiation dermatitis (asymptomatic erythema on their hips; however, in both patients, the erythema was substantially decreased beneath the markers. Patient 2 demonstrated less attenuation and thus greater erythema in the skin covered for three weeks compared to the skin covered for six weeks. The difference in skin changes between the covered and uncovered skin persisted for at least 1 month. A phantom study of double scattered beam SOBP with and without the marker in the beam path showed no gross dosimetric effect. Conclusions Transparent adhesive markers appear to have attenuated radiation dermatitis in

  9. First experiences in treatment of low-grade glioma grade I and II with proton therapy

    Science.gov (United States)

    2012-01-01

    Background To retrospectively assess feasibility and toxicity of proton therapy in patients with low-grade glioma (WHO °I/II). Patients and methods Proton beam therapy only administered in 19 patients (median age 29 years; 9 female, 10 male) for low-grade glioma between 2010 and 2011 was reviewed. In 6 cases proton therapy was performed due to tumor progression after biopsy, in 8 cases each due to tumor progression after (partial-) resection, and in 5 cases due to tumor progression after chemotherapy. Median total dose applied was 54 GyE (range, 48,6-54 GyE) in single fractions of median 1.8 GyE. Median clinical target volume was 99 cc (range, 6–463 cc) and treated using median 2 beams (range, 1–2). Results Proton therapy was finished as planned in all cases. At end of proton therapy, 13 patients showed focal alopecia, 6 patients reported mild fatigue, one patient with temporal tumor localization concentration deficits and speech errors and one more patient deficits in short-term memory. Four patients did not report any side effects. During follow-up, one patient presented with pseudo-progression showing worsening of general condition and brain edema 1–2 months after last irradiation and restitution after 6 months. In the present MR imaging (median follow-up 5 months; range 0–22 months) 12 patients had stable disease, 2 (1) patients partial (complete) remission, one more patient pseudo-progression (differential diagnosis: tumor progression) 4 weeks after irradiation without having had further follow-up imaging so far, and one patient tumor progression approximately 9 months after irradiation. Conclusion Regarding early side effects, mild alopecia was the predominant finding. The rate of alopecia seems to be due to large treatment volumes as well as the anatomical locations of the target volumes and might be avoided by using multiple beams and the gantry in the future. Further evaluations including neuropsychological testing are in preparation. PMID

  10. Early Toxicity in Patients Treated With Postoperative Proton Therapy for Locally Advanced Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Cuaron, John J. [Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Chon, Brian; Tsai, Henry; Goenka, Anuj; DeBlois, David [Procure Proton Therapy Center, Somerset, New Jersey (United States); Ho, Alice; Powell, Simon [Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Hug, Eugen [Procure Proton Therapy Center, Somerset, New Jersey (United States); Cahlon, Oren, E-mail: cahlono@mskcc.org [Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Procure Proton Therapy Center, Somerset, New Jersey (United States)

    2015-06-01

    Purpose: To report dosimetry and early toxicity data in breast cancer patients treated with postoperative proton radiation therapy. Methods and Materials: From March 2013 to April 2014, 30 patients with nonmetastatic breast cancer and no history of prior radiation were treated with proton therapy at a single proton center. Patient characteristics and dosimetry were obtained through chart review. Patients were seen weekly while on treatment, at 1 month after radiation therapy completion, and at 3- to 6-month intervals thereafter. Toxicity was scored using Common Terminology Criteria for Adverse Events version 4.0. Frequencies of toxicities were tabulated. Results: Median dose delivered was 50.4 Gy (relative biological equivalent [RBE]) in 5 weeks. Target volumes included the breast/chest wall and regional lymph nodes including the internal mammary lymph nodes (in 93%). No patients required a treatment break. Among patients with >3 months of follow-up (n=28), grade 2 dermatitis occurred in 20 patients (71.4%), with 8 (28.6%) experiencing moist desquamation. Grade 2 esophagitis occurred in 8 patients (28.6%). Grade 3 reconstructive complications occurred in 1 patient. The median planning target volume V95 was 96.43% (range, 79.39%-99.60%). The median mean heart dose was 0.88 Gy (RBE) [range, 0.01-3.20 Gy (RBE)] for all patients, and 1.00 Gy (RBE) among patients with left-sided tumors. The median V20 of the ipsilateral lung was 16.50% (range, 6.1%-30.3%). The median contralateral lung V5 was 0.34% (range, 0%-5.30%). The median maximal point dose to the esophagus was 45.65 Gy (RBE) [range, 0-65.4 Gy (RBE)]. The median contralateral breast mean dose was 0.29 Gy (RBE) [range, 0.03-3.50 Gy (RBE)]. Conclusions: Postoperative proton therapy is well tolerated, with acceptable rates of skin toxicity. Proton therapy favorably spares normal tissue without compromising target coverage. Further follow-up is necessary to assess for clinical outcomes and cardiopulmonary

  11. Multifield Optimization Intensity Modulated Proton Therapy for Head and Neck Tumors: A Translation to Practice

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Steven J., E-mail: sjfrank@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Cox, James D. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gillin, Michael; Mohan, Radhe [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Garden, Adam S.; Rosenthal, David I.; Gunn, G. Brandon [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Weber, Randal S. [Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Kies, Merrill S. [Department of Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Lewin, Jan S. [Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Munsell, Mark F. [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Palmer, Matthew B. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Sahoo, Narayan; Zhang, Xiaodong; Liu, Wei; Zhu, X. Ronald [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2014-07-15

    Background: We report the first clinical experience and toxicity of multifield optimization (MFO) intensity modulated proton therapy (IMPT) for patients with head and neck tumors. Methods and Materials: Fifteen consecutive patients with head and neck cancer underwent MFO-IMPT with active scanning beam proton therapy. Patients with squamous cell carcinoma (SCC) had comprehensive treatment extending from the base of the skull to the clavicle. The doses for chemoradiation therapy and radiation therapy alone were 70 Gy and 66 Gy, respectively. The robustness of each treatment plan was also analyzed to evaluate sensitivity to uncertainties associated with variations in patient setup and the effect of uncertainties with proton beam range in patients. Proton beam energies during treatment ranged from 72.5 to 221.8 MeV. Spot sizes varied depending on the beam energy and depth of the target, and the scanning nozzle delivered the spot scanning treatment “spot by spot” and “layer by layer.” Results: Ten patients presented with SCC and 5 with adenoid cystic carcinoma. All 15 patients were able to complete treatment with MFO-IMPT, with no need for treatment breaks and no hospitalizations. There were no treatment-related deaths, and with a median follow-up time of 28 months (range, 20-35 months), the overall clinical complete response rate was 93.3% (95% confidence interval, 68.1%-99.8%). Xerostomia occurred in all 15 patients as follows: grade 1 in 10 patients, grade 2 in 4 patients, and grade 3 in 1 patient. Mucositis within the planning target volumes was seen during the treatment of all patients: grade 1 in 1 patient, grade 2 in 8 patients, and grade 3 in 6 patients. No patient experienced grade 2 or higher anterior oral mucositis. Conclusions: To our knowledge, this is the first clinical report of MFO-IMPT for head and neck tumors. Early clinical outcomes are encouraging and warrant further investigation of proton therapy in prospective clinical trials.

  12. A computational implementation and comparison of several intensity modulated proton therapy treatment planning algorithms.

    Science.gov (United States)

    Li, Haisen S; Romeijn, H Edwin; Fox, Christopher; Palta, Jatinder R; Dempsey, James F

    2008-03-01

    The authors present a comparative study of intensity modulated proton therapy (IMPT) treatment planning employing algorithms of three-dimensional (3D) modulation, and 2.5-dimensional (2.5D) modulation, and intensity modulated distal edge tracking (DET) [A. Lomax, Phys. Med. Biol. 44, 185-205 (1999)] applied to the treatment of head-and-neck cancer radiotherapy. These three approaches were also compared with 6 MV photon intensity modulated radiation therapy (IMRT). All algorithms were implemented in the University of Florida Optimized Radiation Therapy system using a finite sized pencil beam dose model and a convex fluence map optimization model. The 3D IMPT and the DET algorithms showed considerable advantages over the photon IMRT in terms of dose conformity and sparing of organs at risk when the beam number was not constrained. The 2.5D algorithm did not show an advantage over the photon IMRT except in the dose reduction to the distant healthy tissues, which is inherent in proton beam delivery. The influences of proton beam number and pencil beam size on the IMPT plan quality were also studied. Out of 24 cases studied, three cases could be adequately planned with one beam and 12 cases could be adequately planned with two beams, but the dose uniformity was often marginally acceptable. Adding one or two more beams in each case dramatically improved the dose uniformity. The finite pencil beam size had more influence on the plan quality of the 2.5D and DET algorithms than that of the 3D IMPT. To obtain a satisfactory plan quality, a 0.5 cm pencil beam size was required for the 3D IMPT and a 0.3 cm size was required for the 2.5D and the DET algorithms. Delivery of the IMPT plans produced in this study would require a proton beam spot scanning technique that has yet to be developed clinically.

  13. Proton pump inhibitor step-down therapy for GERD: A multi-center study in Japan

    Institute of Scientific and Technical Information of China (English)

    Takao Tsuzuki; Hiroyuki Okada; Yoshiro Kawahara; Ryuta Takenaka; Junichiro Nasu; Hidehiko Ishioka; Akiko Fujiwara; Fumiya Yoshinaga; Kazuhide Yamamoto

    2011-01-01

    AIM: To investigate the predictors of success in stepdown of proton pump inhibitor and to assess the quality of life (QOL). METHODS: Patients who had heartburn twice a week or more were treated with 20 mg omeprazole (OPZ) once daily for 8 wk as an initial therapy (study 1). Patients whose heartburn decreased to once a week or less at the end of the initial therapy were enrolled in study 2 and treated with 10 mg OPZ as maintenance therapy for an additional 6 mo (study 2). QOL was investigated using the gastrointestinal symptom rating scale (GSRS) before initial therapy, after both 4 and 8 wk of initial therapy, and at 1, 2, 3, and 6 mo after starting maintenance therapy. RESULTS: In study 1, 108 patients were analyzed. Their characteristics were as follows; median age: 63 (range: 20-88) years, sex: 46 women and 62 men. The success rate of the initial therapy was 76%. In the patients with successful initial therapy, abdominal pain, indigestion and reflux GSRS scores were improved. In study 2, 83 patients were analyzed. Seventy of 83 patients completed the study 2 protocol. In the per-protocol analysis, 80% of 70 patients were successful for stepdown. On multivariate analysis of baseline demographic data and clinical information, no previous treatment for gastroesophageal reflux disease (GERD) [odds ratio (OR) 0.255, 95% CI: 0.06-0.98] and a lower indigestion score in GSRS at the beginning of step-down therapy (OR 0.214, 95% CI: 0.06-0.73) were found to be the predictors of successful step-down therapy. The improved GSRS scores by initial therapy were maintained through the step-down therapy. CONCLUSION: OPZ was effective for most GERD patients. However, those who have had previous treatment for GERD and experience dyspepsia before stepdown require particular monitoring for relapse.

  14. CT based treatment planning system of proton beam therapy for ocular melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, Takashi E-mail: tnakano@med.gunma-u.ac.jp; Kanai, Tatsuaki; Furukawa, Shigeo; Shibayama, Kouichi; Sato, Sinichiro; Hiraoka, Takeshi; Morita, Shinroku; Tsujii, Hirohiko

    2003-09-01

    A computed tomography (CT) based treatment planning system of proton beam therapy was established specially for ocular melanoma treatment. A technique of collimated proton beams with maximum energy of 70 MeV are applied for treatment for ocular melanoma. The vertical proton beam line has a range modulator for spreading beams out, a multi-leaf collimator, an aperture, light beam localizer, field light, and X-ray verification system. The treatment planning program includes; eye model, selecting the best direction of gaze, designing the shape of aperture, determining the proton range and range modulation necessary to encompass the target volume, and indicating the relative positions of the eyes, beam center and creation of beam aperture. Tumor contours are extracted from CT/MRI images of 1 mm thickness by assistant by various information of fundus photography and ultrasonography. The CT image-based treatment system for ocular melanoma is useful for Japanese patients as having thick choroid membrane in terms of dose sparing to skin and normal organs in the eye. The characteristics of the system and merits/demerits were reported.

  15. CT based treatment planning system of proton beam therapy for ocular melanoma

    Science.gov (United States)

    Nakano, Takashi; Kanai, Tatsuaki; Furukawa, Shigeo; Shibayama, Kouichi; Sato, Sinichiro; Hiraoka, Takeshi; Morita, Shinroku; Tsujii, Hirohiko

    2003-09-01

    A computed tomography (CT) based treatment planning system of proton beam therapy was established specially for ocular melanoma treatment. A technique of collimated proton beams with maximum energy of 70 MeV are applied for treatment for ocular melanoma. The vertical proton beam line has a range modulator for spreading beams out, a multi-leaf collimator, an aperture, light beam localizer, field light, and X-ray verification system. The treatment planning program includes; eye model, selecting the best direction of gaze, designing the shape of aperture, determining the proton range and range modulation necessary to encompass the target volume, and indicating the relative positions of the eyes, beam center and creation of beam aperture. Tumor contours are extracted from CT/MRI images of 1 mm thickness by assistant by various information of fundus photography and ultrasonography. The CT image-based treatment system for ocular melanoma is useful for Japanese patients as having thick choroid membrane in terms of dose sparing to skin and normal organs in the eye. The characteristics of the system and merits/demerits were reported.

  16. Secondary neutron doses received by paediatric patients during intracranial proton therapy treatments.

    Science.gov (United States)

    Sayah, R; Farah, J; Donadille, L; Hérault, J; Delacroix, S; De Marzi, L; De Oliveira, A; Vabre, I; Stichelbaut, F; Lee, C; Bolch, W E; Clairand, I

    2014-06-01

    This paper's goal is to assess secondary neutron doses received by paediatric patients treated for intracranial tumours using a 178 MeV proton beam. The MCNPX Monte Carlo model of the proton therapy facility, previously validated through experimental measurements for both proton and neutron dosimetry, was used. First, absorbed dose was calculated for organs located outside the clinical target volume using a series of hybrid computational phantoms for different ages and considering a realistic treatment plan. In general, secondary neutron dose was found to decrease as the distance to the treatment field increases and as the patient age increases. In addition, secondary neutron doses were studied as a function of the beam incidence. Next, neutron equivalent dose was assessed using organ-specific energy-dependent radiation weighting factors determined from Monte Carlo simulations of neutron spectra at each organ. The equivalent dose was found to reach a maximum value of ∼155 mSv at the level of the breasts for a delivery of 49 proton Gy to an intracranial tumour of a one-year-old female patient. Finally, a thorough comparison of the calculation results with published data demonstrated the dependence of neutron dose on the treatment configuration and proved the need for facility-specific and treatment-dependent neutron dose calculations.

  17. The relative costs of proton and X-ray radiation therapy.

    Science.gov (United States)

    Goitein, M; Jermann, M

    2003-02-01

    To study the costs of intensity-modulated proton therapy and intensity-modulated X-ray therapy with the particular goal of understanding their relative differences. To analyse the ratio of the cost per fraction of proton therapy to the cost per fraction of X-ray therapy. We have used a computer spreadsheet tool in which a large number (typically 130) of input parameters characterizing a particular therapeutic modality can be stored. From these parameters a number of derived variables are computed, and from these derived variables the costs of sub-systems, the entire facility, running costs and cost per fraction and per treatment can be computed. The sensitivity of any given variable (e.g. cost/fraction) to any given parameter (e.g. set-up time) can be explored, together with an estimate of the associated confidence interval. The costs of facility construction and facility operation are considered separately. Key data for the input variables regarding the cost of the therapy equipment (a dominant cost for proton beam therapy) were provided by four commercial vendors. Other costs, such as costs for building construction and shielding or personnel costs, are much more standard and our estimates were primarily based on practical experience. We considered two scenarios: (1) both facilities operating under current conditions; and (2) future facilities where foreseeable improvements in efficiency and a 25% reduction in the cost of the proton equipment were assumed. The construction cost of a current two-gantry proton facility, complete with the equipment, was estimated at 62,500 kEE and of a two-linac X-ray facility at 16,800 kEE. In the case of proton therapy the cost of operation of the facility was found to be dominated, by the business cost (42%--primarily the cost of repaying the presumed loan for facility construction), personnel costs (28%) and the cost of servicing the equipment (21%). For X-ray therapy, the cost of operation was seen to be dominated by the

  18. A new concept of radiotherapy: space fractionation in proton therapy; Un nuevo concepto en radioterapia: fraccionamiento espacial en terapia con protones

    Energy Technology Data Exchange (ETDEWEB)

    Prezado Alonso, Y.; Fois, G.

    2013-07-01

    In recent years several experiments with animals have shown that the combination of small field sizes and a spatial neighborhood of the dose of radiation therapy with synchrotron radiation techniques lead to a significant increase of the dose of tolerance of healthy tissues. The aim of this study is to evaluate the feasibility of a new form of radiotherapy: radiotherapy with proton minibeams. (Author)

  19. Dosimetric impact of a CT metal artefact suppression algorithm for proton, electron and photon therapies.

    Science.gov (United States)

    Wei, Jikun; Sandison, George A; Hsi, Wen-Chien; Ringor, Michael; Lu, Xiaoyi

    2006-10-21

    Accurate dose calculation is essential to precision radiation treatment planning and this accuracy depends upon anatomic and tissue electron density information. Modern treatment planning inhomogeneity corrections use x-ray CT images and calibrated scales of tissue CT number to electron density to provide this information. The presence of metal in the volume scanned by an x-ray CT scanner causes metal induced image artefacts that influence CT numbers and thereby introduce errors in the radiation dose distribution calculated. This paper investigates the dosimetric improvement achieved by a previously proposed x-ray CT metal artefact suppression technique when the suppressed images of a patient with bilateral hip prostheses are used in commercial treatment planning systems for proton, electron or photon therapies. For all these beam types, this clinical image and treatment planning study reveals that the target may be severely underdosed if a metal artefact-contaminated image is used for dose calculations instead of the artefact suppressed one. Of the three beam types studied, the metal artefact suppression is most important for proton therapy dose calculations, intermediate for electron therapy and least important for x-ray therapy but still significant. The study of a water phantom having a metal rod simulating a hip prosthesis indicates that CT numbers generated after image processing for metal artefact suppression are accurate and thus dose calculations based on the metal artefact suppressed images will be of high fidelity.

  20. A Monte Carlo-based treatment planning tool for proton therapy

    Science.gov (United States)

    Mairani, A.; Böhlen, T. T.; Schiavi, A.; Tessonnier, T.; Molinelli, S.; Brons, S.; Battistoni, G.; Parodi, K.; Patera, V.

    2013-04-01

    In the field of radiotherapy, Monte Carlo (MC) particle transport calculations are recognized for their superior accuracy in predicting dose and fluence distributions in patient geometries compared to analytical algorithms which are generally used for treatment planning due to their shorter execution times. In this work, a newly developed MC-based treatment planning (MCTP) tool for proton therapy is proposed to support treatment planning studies and research applications. It allows for single-field and simultaneous multiple-field optimization in realistic treatment scenarios and is based on the MC code FLUKA. Relative biological effectiveness (RBE)-weighted dose is optimized either with the common approach using a constant RBE of 1.1 or using a variable RBE according to radiobiological input tables. A validated reimplementation of the local effect model was used in this work to generate radiobiological input tables. Examples of treatment plans in water phantoms and in patient-CT geometries together with an experimental dosimetric validation of the plans are presented for clinical treatment parameters as used at the Italian National Center for Oncological Hadron Therapy. To conclude, a versatile MCTP tool for proton therapy was developed and validated for realistic patient treatment scenarios against dosimetric measurements and commercial analytical TP calculations. It is aimed to be used in future for research and to support treatment planning at state-of-the-art ion beam therapy facilities.

  1. On the Benefits and Risks of Proton Therapy in Pediatric Craniopharyngioma

    Energy Technology Data Exchange (ETDEWEB)

    Beltran, Chris, E-mail: chris.beltran@stjude.org [Division of Radiation Oncology, St Jude Children' s Research Hospital, Memphis, TN (United States); Roca, Monica; Merchant, Thomas E. [Division of Radiation Oncology, St Jude Children' s Research Hospital, Memphis, TN (United States)

    2012-02-01

    Purpose: Craniopharyngioma is a pediatric brain tumor whose volume is prone to change during radiation therapy. We compared photon- and proton-based irradiation methods to determine the effect of tumor volume change on target coverage and normal tissue irradiation in these patients. Methods and Materials: For this retrospective study, we acquired imaging and treatment-planning data from 14 children with craniopharyngioma (mean age, 5.1 years) irradiated with photons (54 Gy) and monitored by weekly magnetic resonance imaging (MRI) examinations during radiation therapy. Photon intensity-modulated radiation therapy (IMRT), double-scatter proton (DSP) therapy, and intensity-modulated proton therapy (IMPT) plans were created for each patient based on his or her pre-irradiation MRI. Target volumes were contoured on each weekly MRI scan for adaptive modeling. The measured differences in conformity index (CI) and normal tissue doses, including functional sub-volumes of the brain, were compared across the planning methods, as was target coverage based on changes in target volumes during treatment. Results: CI and normal tissue dose values of IMPT plans were significantly better than those of the IMRT and DSP plans (p < 0.01). Although IMRT plans had a higher CI and lower optic nerve doses (p < 0.01) than did DSP plans, DSP plans had lower cochlear, optic chiasm, brain, and scanned body doses (p < 0.01). The mean planning target volume (PTV) at baseline was 54.8 cm{sup 3}, and the mean increase in PTV was 11.3% over the course of treatment. The dose to 95% of the PTV was correlated with a change in the PTV; the R{sup 2} values for all models, 0.73 (IMRT), 0.38 (DSP), and 0.62 (IMPT), were significant (p < 0.01). Conclusions: Compared with photon IMRT, proton therapy has the potential to significantly reduce whole-brain and -body irradiation in pediatric patients with craniopharyngioma. IMPT is the most conformal method and spares the most normal tissue; however, it is highly

  2. A comparison of two prompt gamma imaging techniques with collimator-based cameras for range verification in proton therapy

    Science.gov (United States)

    Lin, Hsin-Hon; Chang, Hao-Ting; Chao, Tsi-Chian; Chuang, Keh-Shih

    2017-08-01

    In vivo range verification plays an important role in proton therapy to fully utilize the benefits of the Bragg peak (BP) for delivering high radiation dose to tumor, while sparing the normal tissue. For accurately locating the position of BP, camera equipped with collimators (multi-slit and knife-edge collimator) to image prompt gamma (PG) emitted along the proton tracks in the patient have been proposed for range verification. The aim of the work is to compare the performance of multi-slit collimator and knife-edge collimator for non-invasive proton beam range verification. PG imaging was simulated by a validated GATE/GEANT4 Monte Carlo code to model the spot-scanning proton therapy and cylindrical PMMA phantom in detail. For each spot, 108 protons were simulated. To investigate the correlation between the acquired PG profile and the proton range, the falloff regions of PG profiles were fitted with a 3-line-segment curve function as the range estimate. Factors including the energy window setting, proton energy, phantom size, and phantom shift that may influence the accuracy of detecting range were studied. Results indicated that both collimator systems achieve reasonable accuracy and good response to the phantom shift. The accuracy of range predicted by multi-slit collimator system is less affected by the proton energy, while knife-edge collimator system can achieve higher detection efficiency that lead to a smaller deviation in predicting range. We conclude that both collimator systems have potentials for accurately range monitoring in proton therapy. It is noted that neutron contamination has a marked impact on range prediction of the two systems, especially in multi-slit system. Therefore, a neutron reduction technique for improving the accuracy of range verification of proton therapy is needed.

  3. Water equivalent thickness analysis of immobilization devices for clinical implementation in proton therapy.

    Science.gov (United States)

    Wroe, A J; Ghebremedhin, A; Gordon, I R; Schulte, R W; Slater, J D

    2014-10-01

    Immobilization devices can impact not only the inter- and intra-fraction motion of the patient, but also the range uncertainty of the treatment beam in proton therapy. In order to limit additional range uncertainty, the water equivalent thickness (WET) of the immobilization device needs to be well known and accurately reflected in the calculations by the treatment planning system (TPS). The method presented here focusses on the use of a nozzle-mounted variable range shifter and precision-machined polystyrene blocks of known WET to evaluate commercial immobilization devices prior to clinical implementation. CT studies were also completed to evaluate the internal uniformity of the immobilization devices under study. Mul- tiple inserts of the kVue platform (Qfix Systems, Avondale, PA) were evaluated as part of this study. The results indicate that the inserts are largely interchangeable across a given design type and that the measured WET values agree with those generated by the TPS with a maxi- mum difference less than 1 mm. The WET of the devices, as determined by the TPS, was not impacted by CT beam hardening normally experienced during clinical use. The reproduc- ibility of the WET method was also determined to be better than ±0.02 mm. In conclusion, the testing of immobilization prior to implementation in proton therapy is essential in order to ascertain their impact on the proton treatment and the methodology described here can also be applied to other immobilization systems.

  4. A Project of Boron Neutron Capture Therapy System based on a Proton Linac Neutron Source

    Science.gov (United States)

    Kiyanagi, Yoshikai; Asano, Kenji; Arakawa, Akihiro; Fukuchi, Shin; Hiraga, Fujio; Kimura, Kenju; Kobayashi, Hitoshi; Kubota, Michio; Kumada, Hiroaki; Matsumoto, Hiroshi; Matsumoto, Akira; Sakae, Takeji; Saitoh, Kimiaki; Shibata, Tokushi; Yoshioka, Masakazu

    At present, the clinical trials of Boron Neutron Capture Therapy (BNCT) are being performed at research reactor facilities. However, an accelerator based BNCT has a merit that it can be built in a hospital. So, we just launched a development project for the BNCT based on an accelerator in order to establish and to spread the BNCT as an effective therapy in the near future. In the project, a compact proton linac installed in a hospital will be applied as a neutron source, and energy of the proton beam is planned to be less than about 10 MeV to reduce the radioactivity. The BNCT requires epithermal neutron beam with an intensity of around 1x109 (n/cm2/sec) to deliver the therapeutic dose to a deeper region in a body and to complete the irradiation within an hour. From this condition, the current of the proton beam required is estimated to be a few mA on average. Enormous heat deposition in the target is a big issue. We are aiming at total optimization of the accelerator based BNCT from the linac to the irradiation position. Here, the outline of the project is introduced and the moderator design is presented.

  5. A New Technology for Fast Two-Dimensional Detection of Proton Therapy Beams

    Directory of Open Access Journals (Sweden)

    Robert Hollebeek

    2012-01-01

    chamber and specially designed amplifiers and readout electronics adapted to the requirements of the proton therapy environment and providing both excellent time and high spatial resolution are presented here. The device was irradiated at the Roberts Proton Therapy Center at the University of Pennsylvania. The system was operated with ionization gains between 10 and 200 and in low and intermediate dose-rate beams, and the digitized signal is found to be reproducible to 0.8%. Spatial resolution is determined to be 1.1 mm (1σ with a 1 ms time resolution. We resolve the range modulator wheel rotational frequency and the thicknesses of its segments and show that this information can be quickly measured owing to the high time resolution of the system. Systems of this type will be extremely useful in future treatment methods involving beams that change rapidly in time and spatial position. The Micromegas design resolves the high dose rate within a proton Bragg peak, and measurements agree with Geant4 simulations to within 5%.

  6. Dosimetric impact of tantalum markers used in the treatment of uveal melanoma with proton beam therapy

    Energy Technology Data Exchange (ETDEWEB)

    Newhauser, Wayne D [University of Texas M D Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 94, Houston, TX 77030 (United States); Koch, Nicholas C [University of Texas M D Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 94, Houston, TX 77030 (United States); Fontenot, Jonas D [University of Texas M D Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 94, Houston, TX 77030 (United States); Rosenthal, Stanley J [Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114 (United States); Gombos, Dan S [Section of Opthalmology, Department of Head and Neck Surgery, University of Texas M D Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 94, Houston, TX 77030 (United States); Fitzek, Markus M [Midwest Proton Radiotherapy Institute, 2425 Milo B Sampson Lane, Bloomington, IN 47408 (United States); Mohan, Radhe [University of Texas M D Anderson Cancer Center, 1515 Holcombe Boulevard, Unit 94, Houston, TX 77030 (United States)

    2007-07-07

    Metallic fiducial markers are frequently implanted in patients prior to external-beam radiation therapy to facilitate tumor localization. There is little information in the literature, however, about the perturbations in proton absorbed-dose distribution these objects cause. The aim of this study was to assess the dosimetric impact of perturbations caused by 2.5 mm diameter by 0.2 mm thick tantalum fiducial markers when used in proton therapy for treating uveal melanoma. Absorbed dose perturbations were measured using radiochromic film and confirmed by Monte Carlo simulations of the experiment. Additional Monte Carlo simulations were performed to study the effects of range modulation and fiducial placement location on the magnitude of the dose shadow for a representative uveal melanoma treatment. The simulations revealed that the fiducials caused perturbations in the absorbed-dose distribution, including absorbed-dose shadows of 22% to 82% in a typical proton beam for treating uveal melanoma, depending on the marker depth and orientation. The clinical implication of this study is that implanted fiducials may, in certain circumstances, cause dose shadows that could lower the tumor dose and theoretically compromise local tumor control. To avoid this situation, fiducials should be positioned laterally or distally with respect to the target volume.

  7. Eye tracking and gating system for proton therapy of orbital tumors

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Dongho; Yoo, Seung Hoon; Moon, Sung Ho; Yoon, Myonggeun; Lee, Se Byeong; Park, Sung Yong [Proton Therapy Center, National Cancer Center, Goyang, Gyeonggi 410-769 (Korea, Republic of); Department of Radiation Oncology, CHA Bundang Medical Center, CHA University, Seongnam, Gyeonggi 463-712 (Korea, Republic of); Proton Therapy Center, National Cancer Center, Goyang, Gyeonggi 410-769 (Korea, Republic of); Department of Radiological Science, Korea University, Seoul 136-703 (Korea, Republic of); Proton Therapy Center, National Cancer Center, Goyang, Gyeonggi 410-769 (Korea, Republic of); Proton Therapy Center, McLaren Cancer Institute, Flint, Michigan 48532 (United States)

    2012-07-15

    Purpose: A new motion-based gated proton therapy for the treatment of orbital tumors using real-time eye-tracking system was designed and evaluated. Methods: We developed our system by image-pattern matching, using a normalized cross-correlation technique with LabVIEW 8.6 and Vision Assistant 8.6 (National Instruments, Austin, TX). To measure the pixel spacing of an image consistently, four different calibration modes such as the point-detection, the edge-detection, the line-measurement, and the manual measurement mode were suggested and used. After these methods were applied to proton therapy, gating was performed, and radiation dose distributions were evaluated. Results: Moving phantom verification measurements resulted in errors of less than 0.1 mm for given ranges of translation. Dosimetric evaluation of the beam-gating system versus nongated treatment delivery with a moving phantom shows that while there was only 0.83 mm growth in lateral penumbra for gated radiotherapy, there was 4.95 mm growth in lateral penumbra in case of nongated exposure. The analysis from clinical results suggests that the average of eye movements depends distinctively on each patient by showing 0.44 mm, 0.45 mm, and 0.86 mm for three patients, respectively. Conclusions: The developed automatic eye-tracking based beam-gating system enabled us to perform high-precision proton radiotherapy of orbital tumors.

  8. Strategies for reducing intra-fraction motion induced dosimetric effects in proton therapy

    Science.gov (United States)

    Zhao, Li

    Intra-fraction respiration motion during radiation delivery presents a major challenge to radiation therapy. There has been a growing effort to characterize and manage internal organ motion in radiation therapy, however very few studies focus on tackling this issue in proton therapy. Current practice for treating lung tumors in proton therapy is still to apply population-based margins to account for internal tumor motion, which can lead to target underdosage and normal tissue overdosage. This thesis explores the intra-fraction motion induced dosimetric effects from both computational treatment planning and experimental studies. Four-dimensional CT scans are used to analyze the patient-specific tumor motion characteristics. A feasible method to design the range compensator by using the maximum intensity projection (MIP) images is proposed. Results demonstrate that this MIP approach ensures adequate tumor coverage throughout the entire respiratory cycle whilst maintaining normal tissue dose under clinical constraints. Based on 4D-CT scans, dose convolution is used for assessing the accuracy of Gaussian probability density function for modeling the patient-specific respiratory motion on dose distribution. Non-negligible dose discrepancy is observed in comparisons of convolved dose distributions, and patient-specific respiration PDF is advocated. In addition, an experimental phantom study primarily focusing on the interplay effect between target motion and the scanning beam motion is implemented in two proton beam delivery systems: double scattering and uniform scanning. Measurement results suggest that dose blurring effect is dominant, and interplay effect is trivial in the uniform scanning system due to dose repainting.

  9. Sperm preservation and neutron contamination following proton therapy for prostate cancer study.

    Science.gov (United States)

    Hoppe, Bradford S; Harris, Stephanie; Rhoton-Vlasak, Alice; Bryant, Curtis; Morris, Christopher G; Dagan, Roi; Nichols, Romaine C; Mendenhall, William M; Henderson, Randal H; Li, Zuofeng; Mendenhall, Nancy P

    2017-01-01

    The present study investigates the impact of scatter dose radiation to the testis on ejaculate and sperm counts from treatment of prostate cancer with passive-scatter proton therapy. From March 2010 to November 2014, 20 men with low- or intermediate-risk prostate cancer enrolled in an IRB-approved protocol and provided a semen sample prior to passive-scatter proton therapy and 6-12 months following treatment. Men were excluded if they had high-risk prostate cancer, received androgen deprivation therapy, were on alpha blockers (due to retrograde ejaculation) prior to treatment, had baseline sperm count <1 million, or were unable to produce a pre-treatment sample or could not provide a follow-up specimen. Sperm counts of 0 were considered azoospermia and <15 million/ml were classified as oligospermia. Four patients were unable to provide a sufficient quantity of semen for analysis. Among the 16 remaining patients, only one was found to have oligospermia (7 million/ml). There was a statistically significant reduction in semen volume (median, 0.5 ml) and increase in pH (median 0.5). Although not statistically significant, there appeared to be a decline in sperm concentration (median, 16 million/ml), total sperm count (median, 98.5 million), normal morphology (median, 9%), and rapid progressive motility (median, 9.5%). Men did not have azoospermia 6-12 months following passive-scatter proton therapy indicating minimal scatter radiation to the testis during treatment. Changes in semen quantity and consistency may occur due to prostate irradiation, which could impact future fertility and/or sexual activity.

  10. Proton-pump inhibitor therapy induces acid-related symptoms in healthy volunteers after withdrawal of therapy

    DEFF Research Database (Denmark)

    Reimer, Christina; Søndergaard, Bo; Hilsted, Linda

    2009-01-01

    BACKGROUND & AIMS: Rebound acid hypersecretion (RAHS) has been demonstrated after 8 weeks of treatment with a proton-pump inhibitor (PPI). If RAHS induces acid-related symptoms, this might lead to PPI dependency and thus have important implications. METHODS: A randomized, double-blind, placebo...... dyspepsia, heartburn, or acid regurgitation in the PPI group was 13 of 59 (22%) at week 10, 13 of 59 (22%) at week 11, and 12 of 58 (21%) at week 12. Corresponding figures in the placebo group were 7% at week 10 (P = .034), 5% at week 11 (P = .013), and 2% at week 12 (P = .001). CONCLUSIONS: PPI therapy...

  11. 前列腺癌的质子治疗%Proton therapy in prostate cancer

    Institute of Scientific and Technical Information of China (English)

    张建光; 刘素文

    2009-01-01

    Proton beams have special physical properties, proton therapy for prostate cancer can increase the radiation dose of targets,significantly reduce the doses delivered to organs at risk, reduce the probability of normal tissue complication and secondary malignancies, improve overall survival in patients with localized prostate cancer.%质子具有独特的物理学特性,应用于前列腺癌的治疗,能够提高靶区的照射剂量,显著减少周围正常组织和器官的照射剂量,在照射剂量提高的同时并未增加直肠和膀胱的不良反应,可降低第二原发肿瘤的发生,改善前列腺癌的生存.

  12. On the parametrization of lateral dose profiles in proton radiation therapy

    CERN Document Server

    Embriaco, A

    2015-01-01

    Hadrontherapy requires a good knowledge of the physical interactions of the particles when they cross the biological tissue: one of the aspects that determine the characterization of the beam is the study of the lateral profile. We study different parametrizations for the lateral dose profile of protons beam in water considering different energies at different depth. We compare six functions: we start from the well known Gaussian and Double Gaussian parametrizations and also analyse more recent parametrization obtained with Triple Gaussian and Double Gaussian Lorentz-Cauchy functions. Finally we propose alternative parametrizations based on the Gauss-Rutherford and Gauss-Levy functions. The goal is to improve the performances of the actual treatment planning used in proton beam therapy by suggesting alternative approaches to the Gaussian description typically employed.

  13. Hadron Cancer Therapy - relative merits of X-ray, proton and carbon beams

    Science.gov (United States)

    Jakel, Oliver

    2014-03-01

    -Heidelberg University has a long experience in radiotherapy with carbon ions, starting with a pilot project at GSI in 1997. This project was jointly run by the Dep. for Radiation Oncology of Heidelberg University, GSI and the German Cancer Research Center (DKFZ). A hospital based heavy ion center at Heidelberg University, the Heidelberg Ion Beam Therapy Center (HIT) was proposed by the same group in 1998 and started clinical operation in late 2009. Since then nearly 2000 patients were treated with beams of carbon ions and protons. Just recently the operation of the world's first and only gantry for heavy ions also started at HIT. Patient treatments are performed in three rooms. Besides that, a lot of research projects are run in the field of Medical Physics and Radiobiology using a dedicated experimental area and the possibility to use beams of protons, carbon, helium and oxygen ions being delivered with the raster scanning technique.

  14. Assessment of secondary radiation and radiation protection in laser-driven proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Faby, Sebastian; Wilkens, Jan J. [Technische Univ. Muenchen Klinikum rechts der Isar (Germany). Dept. of Radiation Oncology; Technische Univ. Muenchen (Germany). Physik-Dept.

    2015-09-01

    This work is a feasibility study of a radiation treatment unit with laser-driven protons based on a state-of-the-art energy selection system employing four dipole magnets in a compact shielded beamline. The secondary radiation emitted from the beamline and its energy selection system and the resulting effective dose to the patient are assessed. Further, it is evaluated whether or not such a compact system could be operated in a conventional treatment vault for clinical linear accelerators under the constraint of not exceeding the effective dose limit of 1 mSv per year to the general public outside the treatment room. The Monte Carlo code Geant4 is employed to simulate the secondary radiation generated while irradiating a hypothetical tumor. The secondary radiation inevitably generated inside the patient is taken into account as well, serving as a lower limit. The results show that the secondary radiation emanating from the shielded compact therapy system would pose a serious secondary dose contamination to the patient. This is due to the broad energy spectrum and in particular the angular distribution of the laser-driven protons, which make the investigated beamline together with the employed energy selection system quite inefficient. The secondary radiation also cannot be sufficiently absorbed in a conventional linear accelerator treatment vault to enable a clinical operation. A promising result, however, is the fact that the secondary radiation generated in the patient alone could be very well shielded by a regular treatment vault, allowing the application of more than 100 fractions of 2 Gy per day with protons. It is thus theoretically possible to treat patients with protons in such treatment vaults. Nevertheless, the results show that there is a clear need for alternative more efficient energy selection solutions for laser-driven protons.

  15. SU-E-T-577: Obliquity Factor and Surface Dose in Proton Beam Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Das, I; Andersen, A [Indiana University- School of Medicine, Indianapolis, IN (United States); Coutinho, L [Procure Proton Therapy Center, Somerset, NJ (United States)

    2015-06-15

    Purpose: The advantage of lower skin dose in proton beam may be diminished creating radiation related sequalae usually seen with photon and electron beams. This study evaluates the surface dose as a complex function of beam parameters but more importantly the effect of beam angle. Methods: Surface dose in proton beam depends on the beam energy, source to surface distance, the air gap between snout and surface, field size, material thickness in front of surface, atomic number of the medium, beam angle and type of nozzle (ie double scattering, (DS), uniform scanning (US) or pencil beam scanning (PBS). Obliquity factor (OF) is defined as ratio of surface dose in 0° to beam angle Θ. Measurements were made in water phantom at various beam angles using very small microdiamond that has shown favorable beam characteristics for high, medium and low proton energy. Depth dose measurements were performed in the central axis of the beam in each respective gantry angle. Results: It is observed that surface dose is energy dependent but more predominantly on the SOBP. It is found that as SSD increases, surface dose decreases. In general, SSD, and air gap has limited impact in clinical proton range. High energy has higher surface dose and so the beam angle. The OF rises with beam angle. Compared to OF of 1.0 at 0° beam angle, the value is 1.5, 1.6, 1,7 for small, medium and large range respectively for 60 degree angle. Conclusion: It is advised that just like range and SOBP, surface dose should be clearly understood and a method to reduce the surface dose should be employed. Obliquity factor is a critical parameter that should be accounted in proton beam therapy and a perpendicular beam should be used to reduce surface dose.

  16. Perturbation of water-equivalent thickness as a surrogate for respiratory motion in proton therapy.

    Science.gov (United States)

    Matney, Jason E; Park, Peter C; Li, Heng; Court, Laurence E; Zhu, X Ron; Dong, Lei; Liu, Wei; Mohan, Radhe

    2016-03-08

    Respiratory motion is traditionally assessed using tumor motion magnitude. In proton therapy, respiratory motion causes density variations along the beam path that result in uncertainties of proton range. This work has investigated the use of water-equivalent thickness (WET) to quantitatively assess the effects of respiratory motion on calculated dose in passively scattered proton therapy (PSPT). A cohort of 29 locally advanced non-small cell lung cancer patients treated with 87 PSPT treatment fields were selected for analysis. The variation in WET (ΔWET) along each field was calculated between exhale and inhale phases of the simulation four-dimensional computed tomography. The change in calculated dose (ΔDose) between full-inhale and full-exhale phase was quantified for each field using dose differences, 3D gamma analysis, and differential area under the curve (ΔAUC) analysis. Pearson correlation coefficients were calculated between ΔDose and ΔWET. Three PSPT plans were redesigned using field angles to minimize variations in ΔWET and compared to the original plans. The median ΔWET over 87 treatment fields ranged from 1-9 mm, while the ΔWET 95th percentile value ranged up to 42 mm. The ΔWET was significantly correlated (p respiratory motion, as ΔAUC values were reduced by more than 60% in all three cases. The tumor motion magnitude alone does not capture the potential dosimetric error due to respiratory motion because the proton range is sensitive to the motion of all patient anatomy. The use of ΔWET has been demonstrated to identify situations where respiratory motion can impact the calculated dose. Angular analysis of ΔWET may be capable of designing radiotherapy plans that are more robust to the effects of respiratory motion.

  17. Fast multipurpose Monte Carlo simulation for proton therapy using multi- and many-core CPU architectures.

    Science.gov (United States)

    Souris, Kevin; Lee, John Aldo; Sterpin, Edmond

    2016-04-01

    Accuracy in proton therapy treatment planning can be improved using Monte Carlo (MC) simulations. However the long computation time of such methods hinders their use in clinical routine. This work aims to develop a fast multipurpose Monte Carlo simulation tool for proton therapy using massively parallel central processing unit (CPU) architectures. A new Monte Carlo, called MCsquare (many-core Monte Carlo), has been designed and optimized for the last generation of Intel Xeon processors and Intel Xeon Phi coprocessors. These massively parallel architectures offer the flexibility and the computational power suitable to MC methods. The class-II condensed history algorithm of MCsquare provides a fast and yet accurate method of simulating heavy charged particles such as protons, deuterons, and alphas inside voxelized geometries. Hard ionizations, with energy losses above a user-specified threshold, are simulated individually while soft events are regrouped in a multiple scattering theory. Elastic and inelastic nuclear interactions are sampled from ICRU 63 differential cross sections, thereby allowing for the computation of prompt gamma emission profiles. MCsquare has been benchmarked with the gate/geant4 Monte Carlo application for homogeneous and heterogeneous geometries. Comparisons with gate/geant4 for various geometries show deviations within 2%-1 mm. In spite of the limited memory bandwidth of the coprocessor simulation time is below 25 s for 10(7) primary 200 MeV protons in average soft tissues using all Xeon Phi and CPU resources embedded in a single desktop unit. MCsquare exploits the flexibility of CPU architectures to provide a multipurpose MC simulation tool. Optimized code enables the use of accurate MC calculation within a reasonable computation time, adequate for clinical practice. MCsquare also simulates prompt gamma emission and can thus be used also for in vivo range verification.

  18. Proton Therapy

    Science.gov (United States)

    ... each treatment. Sometimes, there is a need for placement of a metallic marker (fiducial marker) in or ... and listen to the patient closely, using video cameras, to ensure they remain safe and comfortable during ...

  19. Dosimetric intercomparison between protons and electrons therapies applied to retinoblastoma; Intercomparacao dosimetrica entre terapias de protons e eletrons aplicada ao retinoblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Flavia Vieira

    2008-07-01

    In this work we propose a construction of a simple human eye model in order to simulate the dosimetric response for a treatment with protons and electrons in a retinoblastoma cancer. The computational tool used in this simulation was the Geant4 code, in the version 4.9.1, all these package are free and permit simulate the interaction of radiation with matter. In our simulation we use a box with 4 cm side, with water, for represent the human eye. The simulation was performed considering mono energetics beams of protons and electrons with energy range between 50 and 70 MeV for protons and 2 and 10 MeV for electrons. The simulation was based on the advanced hadron therapy example of the Geant 4 code. In these example the phantom is divided in voxels with 0.2 mm side and it is generated the energy deposited in each voxel. The simulation results show the energy deliver in each voxel, with these energie we can calculate the dose deposited in that region. We can see the dose profile of, proton and electron, and we can see in both cases that for protons the position of delivered dose is well know, that happen in the position where the proton stop, for electrons the energies is delivered along the way and pass the desired position for high dose deposition. (author)

  20. A beam optics study of the biomedical beam line at a proton therapy facility

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Chong Cheoul [National Center for Inter-University Research Facilities, Seoul National University, Sillim-dong, Gwanak, Seoul (Korea, Republic of); Kim, Jong-Won [Research Institute and Hospital, National Cancer Center, 809 Madu-dong, Ilsan-gu, Koyang, Kyonggi 410 769 (Korea, Republic of)], E-mail: jwkim@ncc.re.kr

    2007-10-15

    A biomedical beam line has been designed for the experimental area of a proton therapy facility to deliver mm to sub-mm size beams in the energy range of 20-50 MeV using the TRANSPORT/TURTLE beam optics codes and a newly-written program. The proton therapy facility is equipped with a 230 MeV fixed-energy cyclotron and an energy selection system based on a degrader and slits, so that beam currents available for therapy decrease at lower energies in the therapeutic beam energy range of 70-230 MeV. The new beam line system is composed of an energy-degrader, two slits, and three quadrupole magnets. The minimum beam sizes achievable at the focal point are estimated for the two energies of 50 and 20 MeV. The focused FWHM beam size is approximately 0.3 mm with an expected beam current of 20 pA when the beam energy is reduced to 50 MeV from 100 MeV, and roughly 0.8 mm with a current of 10 pA for a 20 MeV beam.

  1. Proton therapy for early stage prostate cancer: is there a case?

    Directory of Open Access Journals (Sweden)

    Chan TY

    2016-09-01

    Full Text Available Tabitha Y Chan, Poh Wee Tan, Johann I Tang Department of Radiation Oncology, National University Cancer Institute, Singapore Abstract: Proton-beam therapy (PBT for prostate cancer has been in used for several decades, with its technique evolving significantly over this period. A growing number of centers now routinely utilize pencil-beam scanning as an advanced technique of PBT. Interest and controversy concerning its use have recently come under scrutiny. While the past decade has produced an assemblage of evidence suggesting that PBT is safe and effective for early stage prostate cancer, it is still unknown whether the theoretical dosimetric advantages of PBT translate into meaningful clinical improvements over routine intensity-modulated radiation therapy, which is commonly used for these patients. Outcomes from early trials using whole courses of PBT have shown mixed results when compared with routine intensity-modulated radiation therapy. Therefore, randomized trials comparing these two techniques should be undertaken, as this would help in defining the role of PBT for this patient group. This article aims to describe the basics of PBT, review the reasons for the growing interest in PBT, review the evidence for PBT, review the controversy surrounding PBT, and inquire about PBT’s future in the treatment of prostate cancer, with attention to its physical properties, comparative clinical and cost-effectiveness, and advances in its delivery. Keywords: proton beam, radiation, prostate cancer, clinical outcomes, controversies, future direction

  2. Tumour Movement in Proton Therapy: Solutions and Remaining Questions: A Review

    Energy Technology Data Exchange (ETDEWEB)

    De Ruysscher, Dirk, E-mail: dirk.deruysscher@uzleuven.be [Department of Oncology, Experimental Radiation Oncology, KU Leuven-University of Leuven, B-3000 Leuven (Belgium); Sterpin, Edmond [Center of Molecular Imaging, Radiotherapy and Oncology, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, B-1200 Brussels (Belgium); Haustermans, Karin; Depuydt, Tom [Department of Oncology, Experimental Radiation Oncology, KU Leuven-University of Leuven, B-3000 Leuven (Belgium)

    2015-06-29

    Movement of tumours, mostly by respiration, has been a major problem for treating lung cancer, liver tumours and other locations in the abdomen and thorax. Organ motion is indeed one component of geometrical uncertainties that includes delineation and target definition uncertainties, microscopic disease and setup errors. At present, minimising motion seems to be the easiest to implement in clinical practice. If combined with adaptive approaches to correct for gradual anatomical variations, it may be a practical strategy. Other approaches such as repainting and tracking could increase the accuracy of proton therapy delivery, but advanced 4D solutions are needed. Moreover, there is a need to perform clinical studies to investigate which approach is the best in a given clinical situation. The good news is that existing and emerging technology and treatment planning systems as will without doubt lead in the forthcoming future to practical solutions to tackle intra-fraction motion in proton therapy. These developments may also improve motion management in photon therapy as well.

  3. Particles that fight cancer: the use of protons and carbon ions in cancer therapy

    CERN Document Server

    CERN. Geneva

    2014-01-01

    Particles that fight cancer: the use of protons and carbon ions in cancer therapy Cancer is a major societal issue. A key challenge for cancer therapy is the complex and multifaceted nature of the disease, which calls for personalised treatment. Radiotherapy has been used to treat tumours for more than a century, and is still a staple in oncology: today, 50 % of cancer patients receive radiotherapy, half of them with curative intent. Hadrontherapy is one of the most technologically advanced methods of delivering radiation dose to the tumour while protecting surrounding healthy tissues. In addition, hadrontherapy can reach otherwise difficult to access deep-seated tumours and can be used for radio resistant tumours as in hypoxia. This year marks 60 years since the first patient was treated with protons in the US and 20 years since the use of carbon ions in Japan. Join us in learning about the journey of particle therapy in Japan and Europe, its challenges, clinical results and future prospects. Thursday 2...

  4. Early Outcomes From Three Prospective Trials of Image-Guided Proton Therapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Mendenhall, Nancy P., E-mail: menden@shands.ufl.edu [University of Florida Proton Therapy Institute, Jacksonville, FL (United States); Li Zuofeng; Hoppe, Bradford S.; Marcus, Robert B.; Mendenhall, William M.; Nichols, R. Charles; Morris, Christopher G. [University of Florida Proton Therapy Institute, Jacksonville, FL (United States); Williams, Christopher R.; Costa, Joseph [Division of Urology, College of Medicine, University of Florida, Jacksonville, FL (United States); Henderson, Randal [University of Florida Proton Therapy Institute, Jacksonville, FL (United States)

    2012-01-01

    Purpose: To report early outcomes with image-guided proton therapy for prostate cancer. Methods and Materials: We accrued 211 prostate cancer patients on prospective Institutional Review Board-approved trials of 78 cobalt gray equivalent (CGE) in 39 fractions for low-risk disease, dose escalation from 78 to 82 CGE for intermediate-risk disease, and 78 CGE with concomitant docetaxel followed by androgen deprivation for high-risk disease. Minimum follow-up was 2 years. Results: One intermediate-risk patient and 2 high-risk patients had disease progression. Pretreatment genitourinary (GU) symptom management was required in 38% of patients. A cumulative 88 (42%) patients required posttreatment GU symptom management. Four transient Grade 3 GU toxicities occurred, all among patients requiring pretreatment GU symptom management. Multivariate analysis showed correlation between posttreatment GU 2+ symptoms and pretreatment GU symptom management (p < 0.0001) and age (p = 0.0048). Only 1 Grade 3+ gastrointestinal (GI) symptom occurred. The prevalence of Grade 2+ GI symptoms was 0 (0%), 10 (5%), 12 (6%), and 8 (4%) at 6, 12, 18, and 24 months, with a cumulative incidence of 20 (10%) patients at 2 years after proton therapy. Univariate and multivariate analyses showed significant correlation between Grade 2+ rectal bleeding and proctitis and the percentage of rectal wall (rectum) receiving doses ranging from 40 CGE (10 CGE) to 80 CGE. Conclusions: Early outcomes with image-guided proton therapy suggest high efficacy and minimal toxicity with only 1.9% Grade 3 GU symptoms and <0.5% Grade 3 GI toxicities.

  5. Proton pump inhibitors therapy vs H2 receptor antagonists therapy for upper gastrointestinal bleeding after endoscopy: A meta-analysis.

    Science.gov (United States)

    Zhang, Ying-Shi; Li, Qing; He, Bo-Sai; Liu, Ran; Li, Zuo-Jing

    2015-05-28

    To compare the therapeutic effects of proton pump inhibitors vs H₂ receptor antagonists for upper gastrointestinal bleeding in patients after successful endoscopy. We searched the Cochrane library, MEDLINE, EMBASE and PubMed for randomized controlled trials until July 2014 for this study. The risk of bias was evaluated by the Cochrane Collaboration's tool and all of the studies had acceptable quality. The main outcomes included mortality, re-bleeding, received surgery rate, blood transfusion units and hospital stay time. These outcomes were estimated using odds ratios (OR) and mean difference with 95% confidence interval (CI). RevMan 5.3.3 software and Stata 12.0 software were used for data analyses. Ten randomized controlled trials involving 1283 patients were included in this review; 678 subjects were in the proton pump inhibitors (PPI) group and the remaining 605 subjects were in the H₂ receptor antagonists (H₂RA) group. The meta-analysis results revealed that after successful endoscopic therapy, compared with H₂RA, PPI therapy had statistically significantly decreased the recurrent bleeding rate (OR = 0.36; 95%CI: 0.25-0.51) and receiving surgery rate (OR = 0.29; 95%CI: 0.09-0.96). There were no statistically significant differences in mortality (OR = 0.46; 95%CI: 0.17-1.23). However, significant heterogeneity was present in both the numbers of patients requiring blood transfusion after treatment [weighted mean difference (WMD), -0.70 unit; 95%CI: -1.64 - 0.25] and the time that patients remained hospitalized [WMD, -0.77 d; 95%CI: -1.87 - 0.34]. The Begg's test (P = 0.283) and Egger's test (P = 0.339) demonstrated that there was no publication bias in our meta-analysis. In patients with upper gastrointestinal bleeding after successful endoscopic therapy, compared with H₂RA, PPI may be a more effective therapy.

  6. Optimization of adaptive radiation therapy in cervical cancer: Solutions for photon and proton therapy

    NARCIS (Netherlands)

    van de Schoot, A.J.A.J.

    2016-01-01

    In cervical cancer radiation therapy, an adaptive strategy is required to compensate for interfraction anatomical variations in order to achieve adequate dose delivery. In this thesis, we have aimed at optimizing adaptive radiation therapy in cervical cancer to improve treatment efficiency and

  7. Optimization of adaptive radiation therapy in cervical cancer: Solutions for photon and proton therapy

    NARCIS (Netherlands)

    van de Schoot, A.J.A.J.

    2016-01-01

    In cervical cancer radiation therapy, an adaptive strategy is required to compensate for interfraction anatomical variations in order to achieve adequate dose delivery. In this thesis, we have aimed at optimizing adaptive radiation therapy in cervical cancer to improve treatment efficiency and reduc

  8. SUPERCONDUCTING NON-SCALING FFAG GANTRY FOR CARBON-PROTON CANCER THERAPY

    Energy Technology Data Exchange (ETDEWEB)

    TRBOJEVIC,D.; GUPTA, R.; PARKER, B.; KEIL, E.; SESSLER, A.M.

    2007-06-25

    We report on improvements in the non-scaling Fixed Field Alternating Gradient (FFAG) gantry design. As we previously reported, a major challenge of the carbodproton cancer therapy facilities is isocentric gantry design. The weight of the isocentric gantry transport elements in the latest Heidelberg carbon/proton facility is 135 tons. In this report we detail improvements to the previous non-scaling gantry design. We estimate that this non-scaling FFAG gantry would be almost hundred times lighter than traditional heavy ion gantries. Very strong focusing with small dispersion permits passage of different energies of carbon beams through the gantry's fixed magnetic field.

  9. A fast Monte Carlo code for proton transport in radiation therapy based on MCNPX

    OpenAIRE

    Keyvan Jabbari; Jan Seuntjens

    2014-01-01

    An important requirement for proton therapy is a software for dose calculation. Monte Carlo is the most accurate method for dose calculation, but it is very slow. In this work, a method is developed to improve the speed of dose calculation. The method is based on pre-generated tracks for particle transport. The MCNPX code has been used for generation of tracks. A set of data including the track of the particle was produced in each particular material (water, air, lung tissue, bone, and soft t...

  10. Proton therapy versus photon radiation therapy for the management of a recurrent desmoid tumor of the right flank: a case report

    Directory of Open Access Journals (Sweden)

    Kil Whoon

    2012-10-01

    Full Text Available Abstract Desmoid tumors are benign mesenchymal tumors with a strong tendency for local recurrence after surgery. Radiotherapy improves local control following incomplete resection, but nearby organs at risk may limit the dose to the target volume. The patient in this report presented with a recurrent desmoid tumor of the right flank and underwent surgery with microscopically positive margins. Particular problems presented in this case included that the tumor bed was situated in close proximity to the liver and the right kidney and that the right kidney was responsible for 65% of the patient’s renal function. Intensity-modulated radiation therapy plans delivering 54 Gy necessarily exposed the right kidney to a V18 of 98% and the liver to a V30 of 55%. Proton therapy plans significantly reduced the right kidney V18 to 32% and the liver V30 to 28%. In light of this, the proton plan was utilized for treatment of this patient. Proton therapy was tolerated without gastrointestinal discomfort or other complaints. Twenty-four months after initiation of proton therapy, the patient is without clinical or radiographic evidence of disease recurrence. In this setting, the improved dose distribution associated with proton therapy allowed for curative treatment of a patient who arguably could not have been safely treated with intensity-modulated radiation therapy or other methods of conventional radiotherapy.

  11. Rectal Toxicity After Proton Therapy For Prostate Cancer: An Analysis of Outcomes of Prospective Studies Conducted at the University of Florida Proton Therapy Institute

    Energy Technology Data Exchange (ETDEWEB)

    Colaco, Rovel J.; Hoppe, Bradford S.; Flampouri, Stella [The University of Florida Proton Therapy Institute, Jacksonville, Florida (United States); McKibben, Brian T. [Baptist Health Medical Center, Department of Surgery, Jacksonville, Florida (United States); Henderson, Randal H.; Bryant, Curtis; Nichols, Romaine C.; Mendenhall, William M.; Li, Zuofeng; Su, Zhong [The University of Florida Proton Therapy Institute, Jacksonville, Florida (United States); Morris, Christopher G. [Baptist Health Medical Center, Department of Surgery, Jacksonville, Florida (United States); Mendenhall, Nancy P., E-mail: menden@floridaproton.org [The University of Florida Proton Therapy Institute, Jacksonville, Florida (United States)

    2015-01-01

    Purpose: Study goals were to characterize gastrointestinal effects of proton therapy (PT) in a large cohort of patients treated for prostate cancer, identify factors associated with rectal bleeding (RB), and compare RB between patients receiving investigational protocols versus those in outcome-tracking protocols. Methods and Materials: A total of 1285 consecutive patients were treated with PT between August 2006 and May 2010. Potential pre-existing clinical and treatment-related risk factors for rectal toxicity were recorded. Common Terminology Criteria for Adverse Events version 3.0 was used to score toxicity. Results: Transient RB was the predominant grade 2 or higher (GR2+) toxicity after PT, accounting for 95% of gastrointestinal events. GR1 RB occurred in 217 patients (16.9%), GR2 RB in 187 patients (14.5%), and GR3 in 11 (0.9%) patients. There were no GR4 or GR5 events. Univariate analyses showed correlations between GR2+ RB and anticoagulation therapy (P=.008) and rectal and rectal wall dose-volume histogram (DVH) parameters (P<.001). On multivariate analysis, anticoagulation therapy (P=.0034), relative volume of rectum receiving 75 Gy (V75; P=.0102), and relative rectal wall V75 (P=.0017) were significant predictors for G2+ RB. Patients treated with investigational protocols had toxicity rates similar to those receiving outcome-tracking protocols. Conclusions: PT was associated with a low rate of GR2+ gastrointestinal toxicity, predominantly transient RB, which was highly correlated with anticoagulation and rectal DVH parameters. Techniques that limit rectal exposure should be used when possible.

  12. SU-E-T-28: A Treatment Planning Comparison of Volumetric Modulated Arc Therapy Vs. Proton Therapy for Post-Mastectomy Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, M; Zhang, R; Sanders, M; Newhauser, W [Louisiana State University, Baton Rouge, LA (United States)

    2014-06-01

    Purpose: The delivery of post-mastectomy radiotherapy (PMRT) can be challenging for patients with left-sided breast cancer due to the PTV size and proximity to critical organs. This study investigates the use of protons for PMRT in a clinically-representative cohort of patients, and quantitatively compares volumetric modulated arc therapy (VMAT) to proton therapy to have an evidence-based rationale for selecting a treatment modality for these patients. Methods: Eight left-sided PMRT patients previously treated at our clinic with VMAT were identified for the study. PTVs included the chest wall and regional lymph nodes. Passively scattered (PS) and intensity modulated proton therapy (IMPT) plans were constructed using the Eclipse proton planning system. The resulting plans were compared to the original VMAT plan on the basis of PTV coverage; dose homogeneity index (DHI) and conformity index (CI); dose to organs at risk (OAR); tumor control probability (TCP), normal tissue complication probability (NTCP) and secondary cancer complication probability (SCCP). Differences were tested for significance using the paired Student's t-test (p<0.01). Results: All modalities produced clinically acceptable PMRT plans. The comparison demonstrated proton treatment plans provide significantly lower NTCP values for the heart and the lung while maintaining significantly better CI and DHI. At a prescribed dose of 50.4 Gy (RBE) in the PTV, the calculated mean NTCP value for the patients decreased from 1.3% to 0.05% for the whole heart (cardiac mortality) and from 3.8% to 1.1% for the lungs (radiation pneumonitis) for both proton therapy plans from VMAT plans. Both proton modalities showed a significantly lower SCCP for the contralateral breast compared to VMAT. Conclusion: All three plans (VMAT, PS, and IMPT) provide acceptable treatment plans for PMRT. However, proton therapy shows a significant advantage over VMAT with regards to sparing OARs and may be more advantageous for

  13. A fast Monte Carlo code for proton transport in radiation therapy based on MCNPX.

    Science.gov (United States)

    Jabbari, Keyvan; Seuntjens, Jan

    2014-07-01

    An important requirement for proton therapy is a software for dose calculation. Monte Carlo is the most accurate method for dose calculation, but it is very slow. In this work, a method is developed to improve the speed of dose calculation. The method is based on pre-generated tracks for particle transport. The MCNPX code has been used for generation of tracks. A set of data including the track of the particle was produced in each particular material (water, air, lung tissue, bone, and soft tissue). This code can transport protons in wide range of energies (up to 200 MeV for proton). The validity of the fast Monte Carlo (MC) code is evaluated with data MCNPX as a reference code. While analytical pencil beam algorithm transport shows great errors (up to 10%) near small high density heterogeneities, there was less than 2% deviation of MCNPX results in our dose calculation and isodose distribution. In terms of speed, the code runs 200 times faster than MCNPX. In the Fast MC code which is developed in this work, it takes the system less than 2 minutes to calculate dose for 10(6) particles in an Intel Core 2 Duo 2.66 GHZ desktop computer.

  14. A fast Monte Carlo code for proton transport in radiation therapy based on MCNPX

    Directory of Open Access Journals (Sweden)

    Keyvan Jabbari

    2014-01-01

    Full Text Available An important requirement for proton therapy is a software for dose calculation. Monte Carlo is the most accurate method for dose calculation, but it is very slow. In this work, a method is developed to improve the speed of dose calculation. The method is based on pre-generated tracks for particle transport. The MCNPX code has been used for generation of tracks. A set of data including the track of the particle was produced in each particular material (water, air, lung tissue, bone, and soft tissue. This code can transport protons in wide range of energies (up to 200 MeV for proton. The validity of the fast Monte Carlo (MC code is evaluated with data MCNPX as a reference code. While analytical pencil beam algorithm transport shows great errors (up to 10% near small high density heterogeneities, there was less than 2% deviation of MCNPX results in our dose calculation and isodose distribution. In terms of speed, the code runs 200 times faster than MCNPX. In the Fast MC code which is developed in this work, it takes the system less than 2 minutes to calculate dose for 10 6 particles in an Intel Core 2 Duo 2.66 GHZ desktop computer.

  15. Assessment of Geant4 prompt gamma emission yields in the context of proton therapy monitoring

    Directory of Open Access Journals (Sweden)

    Marco ePinto

    2016-01-01

    Full Text Available Monte Carlo tools have been long used to assist the research and development of solutions for proton therapy monitoring. The present work focuses on the prompt-gamma emission yields by comparing experimental data with the outcomes of the current version of Geant4 using all applicable proton inelastic models. For the case in study and using the binary cascade model, it was found that Geant4 overestimates the prompt-gamma emission yields by 40.2+/-0.3%, even though it predicts the prompt-gamma profile length of the experimental profile accurately. In addition, the default implementations of all proton inelastic models show an overestimation in the number of prompt gammas emitted. Finally, a set of built-in options and physically-sound Geant4 source code changes have been tested in order to try to improve the discrepancy observed. A satisfactory agreement was found when using the QMD model with a wave packet width equal to 1.3 fm2.

  16. Optimizing proton pump inhibitor therapy for treatment of nonvariceal upper gastrointestinal bleeding.

    Science.gov (United States)

    Worden, Jarett C; Hanna, Kirollos S

    2017-02-01

    The pharmacology, rationale, and dosing optimization strategies of proton pump inhibitors (PPIs) for the treatment of upper gastrointestinal bleeding (UGIB) are discussed. In combination with endoscopic therapy, PPIs are the treatment of choice for UGIB. While the advent of PPIs has improved patient outcomes, controversy still exists over optimal PPI therapy for UGIB. Pharmacologic treatment in combination with endoscopic therapy has demonstrated improved outcomes in patients with nonvariceal UGIB. PPIs are the treatment of choice for suppressing gastric acid and preventing rebleeding, though a mortality benefit from these agents has not been strongly established. Although the current guidelines recommend an i.v. bolus injection followed by continuous infusion of a high-dose PPI, intermittent PPI therapy has been found to be safe and effective while significantly reducing cost, even in patients with high-risk stigmata after endoscopy. Oral PPIs may be effective in patients who can tolerate oral therapy but require further evaluation in patients with higher-risk stigmata. Regardless of stigmata, after 72 hours of i.v. therapy, patients with UGIB may be safely transitioned to oral PPIs if hemodynamically stable and able to tolerate oral medication. As the risk of rebleeding significantly decreases after the first three days, continuation of high-dose therapy beyond 72 hours is not necessary in hemodynamically stable patients. Current guidelines recommend that PPIs be given as an i.v. bolus injection followed by a continuous infusion, but intermittent i.v. dosing and oral PPI therapy have been found to be effective in treating patients with UGIB and associated with reductions in cost. Copyright © 2017 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

  17. Addition of cranberry to proton pump inhibitor-based triple therapy for Helicobacter pylori eradication

    Science.gov (United States)

    Seyyedmajidi, Mohammadreza; Ahmadi, Anahita; Hajiebrahimi, Shahin; Seyedmajidi, Seyedali; Rajabikashani, Majid; Firoozabadi, Mona; Vafaeimanesh, Jamshid

    2016-01-01

    Objective: Proton pump inhibitor-based triple therapy with two antibiotics for Helicobacter pylori eradication is widely accepted, but this combination fails in a considerable number of cases. Some studies have shown that cranberry inhibits the adhesion of a wide range of microbial pathogens, including H. pylori. The aim of this study was to assess the effect of cranberry on H. pylori eradication with a standard therapy including lansoprazole, clarithromycin, and amoxicillin (LCA) in patients with peptic ulcer disease (PUD). Methods: In this study, H. pylori-positive patients with PUD were randomized into two groups: Group A: A 14-day LCA triple therapy with 30 mg lansoprazole bid, 1000 mg amoxicillin bid, and 500 mg clarithromycin bid; Group B: A 14-day 500 mg cranberry capsules bid plus LCA triple therapy. A 13C-urea breath test was performed for eradication assessment 6 weeks after the completion of the treatment. Findings: Two hundred patients (53.5% males, between 23 and 77 years, mean age ± standard deviation: 50.29 ± 17.79 years) continued treatment protocols and underwent 13C-urea breath testing. H. pylori eradication was achieved in 74% in Group A (LCA without cranberry) and 89% in Group B (LCA with cranberry) (P = 0.042). Conclusion: The addition of cranberry to LCA triple therapy for H. pylori has a higher rate of eradication than the standard regimen alone (up to 89% and significant). PMID:27843960

  18. Proton therapy for head and neck cancer: Rationale, potential indications, practical considerations, and current clinical evidence

    Energy Technology Data Exchange (ETDEWEB)

    Mendenhall, Nancy P.; Malyapa, Robert S.; Su, Zhong; Yeung, Daniel; Mendenhall, William M.; Li, Zuofeng (Univ. of Florida Proton Therapy Inst., Jacksonville, Florida (United States)), e-mail: menden@shands.ufl.edu

    2011-08-15

    There is a strong rationale for potential benefits from proton therapy (PT) for selected cancers of the head and neck because of the opportunity to improve the therapeutic ratio by improving radiation dose distributions and because of the significant differences in radiation dose distribution achievable with x-ray-based radiation therapy (RT) and PT. Comparisons of dose distributions between x-ray-based and PT plans in selected cases show specific benefits in dose distribution likely to translate into improved clinical outcomes. However, the use of PT in head and neck cancers requires special considerations in the simulation and treatment planning process, and currently available PT technology may not permit realization of the maximum potential benefits of PT. To date, few clinical data are available, but early clinical experiences in sinonasal tumors in particular suggest significant improvements in both disease control and radiation-related toxicity

  19. Aspects of the physical principles of the proton therapy with inclusion of nuclear interactions

    CERN Document Server

    Ulmer, W

    2016-01-01

    The radiotherapy of malignant diseases has reached much progress during the past decade. Thus, intensity modulated radiation therapy (IMRT) and VMAT (Rapidarc) now belong to the standard modalities of tumor treatment with high energy radiation in clinical practice. In recent time, the particle therapy (protons and partially with heavy carbon ions) has reached an important completion of these modalities with regard to some suitable applications. In spite of this enrichment essential features need further research activities and publications in this field: Nuclear reactions and the role of the released neutrons, electron capture of positively charged nuclei at lower projectile energies (e.g. in the environment of the Bragg peak and at the distal end of the particle track), correct dose delivery in scanning methods by accounting for the influence of the lateral scatter of beam-lets. Deconvolution methods can help to overcome these problems, which already occur in radiotherapy of very small photon beams [1 - 8].

  20. Prompt gamma imaging with a slit camera for real-time range control in proton therapy.

    Science.gov (United States)

    Smeets, J; Roellinghoff, F; Prieels, D; Stichelbaut, F; Benilov, A; Busca, P; Fiorini, C; Peloso, R; Basilavecchia, M; Frizzi, T; Dehaes, J C; Dubus, A

    2012-06-07

    Treatments delivered by proton therapy are affected by uncertainties on the range of the beam within the patient, requiring medical physicists to add safety margins on the penetration depth of the beam. To reduce these margins and deliver safer treatments, different projects are currently investigating real-time range control by imaging prompt gammas emitted along the proton tracks in the patient. This study reports on the feasibility, development and test of a new concept of prompt gamma camera using a slit collimator to obtain a one-dimensional projection of the beam path on a scintillation detector. This concept was optimized, using the Monte Carlo code MCNPX version 2.5.0, to select high energy photons correlated with the beam range and detect them with both high statistics and sufficient spatial resolution. To validate the Monte Carlo model, spectrometry measurements of secondary particles emitted by a PMMA target during proton irradiation at 160 MeV were realized. An excellent agreement with the simulations was observed when using subtraction methods to isolate the gammas in direct incidence. A first prototype slit camera using the HiCam gamma detector was consequently prepared and tested successfully at 100 and 160 MeV beam energies. Results confirmed the potential of this concept for real-time range monitoring with millimetre accuracy in pencil beam scanning mode for typical clinical conditions. If we neglect electronic dead times and rejection of detected events, the current solution with its collimator at 15 cm from the beam axis can achieve a 1-2 mm standard deviation on range estimation in a homogeneous PMMA target for numbers of protons that correspond to doses in water at the Bragg peak as low as 15 cGy at 100 MeV and 25 cGy at 160 MeV assuming pencil beams with a Gaussian profile of 5 mm sigma at target entrance.

  1. Partial Breast Radiation Therapy With Proton Beam: 5-Year Results With Cosmetic Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Bush, David A., E-mail: dbush@llu.edu [Department of Radiation Oncology, Loma Linda University Medical Center, Loma Linda, California (United States); Do, Sharon [Department of Radiation Oncology, Loma Linda University Medical Center, Loma Linda, California (United States); Lum, Sharon; Garberoglio, Carlos [Department of Surgical Oncology, Loma Linda University Medical Center, Loma Linda, California (United States); Mirshahidi, Hamid [Department of Medical Oncology, Loma Linda University Medical Center, Loma Linda, California (United States); Patyal, Baldev; Grove, Roger; Slater, Jerry D. [Department of Radiation Oncology, Loma Linda University Medical Center, Loma Linda, California (United States)

    2014-11-01

    Purpose: We updated our previous report of a phase 2 trial using proton beam radiation therapy to deliver partial breast irradiation (PBI) in patients with early stage breast cancer. Methods and Materials: Eligible subjects had invasive nonlobular carcinoma with a maximal dimension of 3 cm. Patients underwent partial mastectomy with negative margins; axillary lymph nodes were negative on sampling. Subjects received postoperative proton beam radiation therapy to the surgical bed. The dose delivered was 40 Gy in 10 fractions, once daily over 2 weeks. Multiple fields were treated daily, and skin-sparing techniques were used. Following treatment, patients were evaluated with clinical assessments and annual mammograms to monitor toxicity, tumor recurrence, and cosmesis. Results: One hundred subjects were enrolled and treated. All patients completed the assigned treatment and were available for post-treatment analysis. The median follow-up was 60 months. Patients had a mean age of 63 years; 90% had ductal histology; the average tumor size was 1.3 cm. Actuarial data at 5 years included ipsilateral breast tumor recurrence-free survival of 97% (95% confidence interval: 100%-93%); disease-free survival of 94%; and overall survival of 95%. There were no cases of grade 3 or higher acute skin reactions, and late skin reactions included 7 cases of grade 1 telangiectasia. Patient- and physician-reported cosmesis was good to excellent in 90% of responses, was not changed from baseline measurements, and was well maintained throughout the entire 5-year follow-up period. Conclusions: Proton beam radiation therapy for PBI produced excellent ipsilateral breast recurrence-free survival with minimal toxicity. The treatment proved to be adaptable to all breast sizes and lumpectomy cavity configurations. Cosmetic results appear to be excellent and unchanged from baseline out to 5 years following treatment. Cosmetic results may be improved over those reported with photon

  2. Malfunctions of Implantable Cardiac Devices in Patients Receiving Proton Beam Therapy: Incidence and Predictors

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Daniel R., E-mail: dgomez@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Poenisch, Falk [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Pinnix, Chelsea C. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Sheu, Tommy [Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chang, Joe Y. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Memon, Nada [Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Rozner, Marc A. [Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Dougherty, Anne H. [Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2013-11-01

    Purpose: Photon therapy has been reported to induce resets of implanted cardiac devices, but the clinical sequelae of treating patients with such devices with proton beam therapy (PBT) are not well known. We reviewed the incidence of device malfunctions among patients undergoing PBT. Methods and Materials: From March 2009 through July 2012, 42 patients with implanted cardiac implantable electronic devices (CIED; 28 pacemakers and 14 cardioverter-defibrillators) underwent 42 courses of PBT for thoracic (23, 55%), prostate (15, 36%), liver (3, 7%), or base of skull (1, 2%) tumors at a single institution. The median prescribed dose was 74 Gy (relative biological effectiveness; range 46.8-87.5 Gy), and the median distance from the treatment field to the CIED was 10 cm (range 0.8-40 cm). Maximum proton and neutron doses were estimated for each treatment course. All CIEDs were checked before radiation delivery and monitored throughout treatment. Results: Median estimated peak proton and neutron doses to the CIED in all patients were 0.8 Gy (range 0.13-21 Gy) and 346 Sv (range 11-1100 mSv). Six CIED malfunctions occurred in 5 patients (2 pacemakers and 3 defibrillators). Five of these malfunctions were CIED resets, and 1 patient with a defibrillator (in a patient with a liver tumor) had an elective replacement indicator after therapy that was not influenced by radiation. The mean distance from the proton beam to the CIED among devices that reset was 7.0 cm (range 0.9-8 cm), and the mean maximum neutron dose was 655 mSv (range 330-1100 mSv). All resets occurred in patients receiving thoracic PBT and were corrected without clinical incident. The generator for the defibrillator with the elective replacement indicator message was replaced uneventfully after treatment. Conclusions: The incidence of CIED resets was about 20% among patients receiving PBT to the thorax. We recommend that PBT be avoided in pacing-dependent patients and that patients with any type of CIED receiving

  3. Outcomes of Proton Radiation Therapy for Peripapillary Choroidal Melanoma at the BC Cancer Agency

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Eric, E-mail: etran2@bccancer.bc.ca [Radiation Therapy Program, BC Cancer Agency and University of British Columbia, Vancouver, British Columbia (Canada); Ma, Roy [Radiation Therapy Program, BC Cancer Agency and University of British Columbia, Vancouver, British Columbia (Canada); Paton, Katherine [Department of Ophthalmology and Visual Sciences, Vancouver Hospital Eye Care Centre and University of British Columbia, Vancouver, British Columbia (Canada); Blackmore, Ewart [TRIUMF, Vancouver, British Columbia (Canada); Pickles, Tom [Radiation Therapy Program, BC Cancer Agency and University of British Columbia, Vancouver, British Columbia (Canada)

    2012-08-01

    Purpose: To report toxicity, local control, enucleation, and survival rates for patients with peripapillary choroidal melanoma treated with proton therapy in Canada. Methods and Materials: We performed a retrospective analysis of patients with peripapillary choroidal melanoma ({<=}2 mm from optic disc) treated between 1995 and 2007 at the only Canadian proton therapy facility. A prospective database was updated for follow-up information from a chart review. Descriptive and actuarial data are presented. Results: In total, 59 patients were treated. The median age was 59 years. According to the 2010 American Joint Committee on Cancer TNM classification, there were 20 T1 tumors (34%), 28 T2 tumors (48%), and 11 T3 tumors (19%). The median tumor diameter was 11.4 mm, and the median thickness was 3.5 mm. Median follow-up was 63 months. Nineteen patients received 54 cobalt gray equivalents (CGE) and forty patients received 60 CGE, each in 4 fractions. The 5-year actuarial local control rate was 91% (T1, 100%; T2, 93%; and T3, 59%) (p = 0.038). There was a suggestive relationship between local control and dose. The local control rate was 97% with 60 CGE and 83% with 54 CGE (p = 0.106). The metastasis-free survival rate was 82% and related to T stage (T1, 94%; T2, 84%; and T3, 47%) (p < 0.001). Twelve patients died, including eleven with metastases. The 5-year actuarial rate of neovascular glaucoma was 31% (23% for T1-T2 and 68% for T3, p < 0.001), and that of enucleation was 0% for T1, 14% for T2, and 72% for T3 (p < 0.001). Radiation retinopathy (74%) and optic neuropathy (64%) were common within-field effects. Conclusions: Proton therapy provides excellent local control with acceptable toxicity while conserving the globe in 80% of cases. These results are consistent with other single-institution series using proton radiotherapy, and toxicity rates were acceptable. T3 tumors carry a higher rate of both local recurrence and metastasis.

  4. Establishing Evidence-Based Indications for Proton Therapy: An Overview of Current Clinical Trials.

    Science.gov (United States)

    Mishra, Mark V; Aggarwal, Sameer; Bentzen, Soren M; Knight, Nancy; Mehta, Minesh P; Regine, William F

    2017-02-01

    To review and assess ongoing proton beam therapy (PBT) clinical trials and to identify major gaps. Active PBT clinical trials were identified from clinicaltrials.gov and the World Health Organization International Clinical Trials Platform Registry. Data on clinical trial disease site, age group, projected patient enrollment, expected start and end dates, study type, and funding source were extracted. A total of 122 active PBT clinical trials were identified, with target enrollment of >42,000 patients worldwide. Ninety-six trials (79%), with a median planned sample size of 68, were classified as interventional studies. Observational studies accounted for 21% of trials but 71% (n=29,852) of planned patient enrollment. The most common PBT clinical trials focus on gastrointestinal tract tumors (21%, n=26), tumors of the central nervous system (15%, n=18), and prostate cancer (12%, n=15). Five active studies (lung, esophagus, head and neck, prostate, breast) will randomize patients between protons and photons, and 3 will randomize patients between protons and carbon ion therapy. The PBT clinical trial portfolio is expanding rapidly. Although the majority of ongoing studies are interventional, the majority of patients will be accrued to observational studies. Future efforts should focus on strategies to encourage optimal patient enrollment and retention, with an emphasis on randomized, controlled trials, which will require support from third-party payers. Results of ongoing PBT studies should be evaluated in terms of comparative effectiveness, as well as incremental effectiveness and value offered by PBT in comparison with conventional radiation modalities. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Measurements and simulations of boron carbide as degrader material for proton therapy

    Science.gov (United States)

    Gerbershagen, Alexander; Baumgarten, Christian; Kiselev, Daniela; van der Meer, Robert; Risters, Yannic; Schippers, Marco

    2016-07-01

    We report on test measurements using boron carbide (B4C) as degrader material in comparison with the conventional graphite, which is currently used in many proton therapy degraders. Boron carbide is a material of lower average atomic weight and higher density than graphite. Calculations predict that, compared to graphite, the use of boron carbide results in a lower emittance behind the degrader due to the shorter degrader length. Downstream of the acceptance defining collimation system we expect a higher beam transmission, especially at low beam energies. This is of great interest in proton therapy applications as it allows either a reduction of the beam intensity extracted from the cyclotron leading to lower activation or a reduction of the treatment time. This paper summarizes the results of simulations and experiments carried out at the PROSCAN facility at the Paul Scherrer Institute1. The simulations predict an increase in the transmitted beam current after the collimation system of approx. 30.5% for beam degradation from 250 to 84 MeV for a boron carbide degrader compared to graphite. The experiment carried out with a boron carbide block reducing the energy to 84 MeV yielded a transmission improvement of 37% compared with the graphite degrader set to that energy.

  6. Measurements and simulations of boron carbide as degrader material for proton therapy.

    Science.gov (United States)

    Gerbershagen, Alexander; Baumgarten, Christian; Kiselev, Daniela; van der Meer, Robert; Risters, Yannic; Schippers, Marco

    2016-07-21

    We report on test measurements using boron carbide (B4C) as degrader material in comparison with the conventional graphite, which is currently used in many proton therapy degraders. Boron carbide is a material of lower average atomic weight and higher density than graphite. Calculations predict that, compared to graphite, the use of boron carbide results in a lower emittance behind the degrader due to the shorter degrader length. Downstream of the acceptance defining collimation system we expect a higher beam transmission, especially at low beam energies. This is of great interest in proton therapy applications as it allows either a reduction of the beam intensity extracted from the cyclotron leading to lower activation or a reduction of the treatment time. This paper summarizes the results of simulations and experiments carried out at the PROSCAN facility at the Paul Scherrer Institute(1). The simulations predict an increase in the transmitted beam current after the collimation system of approx. 30.5% for beam degradation from 250 to 84 MeV for a boron carbide degrader compared to graphite. The experiment carried out with a boron carbide block reducing the energy to 84 MeV yielded a transmission improvement of 37% compared with the graphite degrader set to that energy.

  7. Dosimetric Comparison of Three-Dimensional Conformal Proton Radiotherapy, Intensity-Modulated Proton Therapy, and Intensity-Modulated Radiotherapy for Treatment of Pediatric Craniopharyngiomas

    Energy Technology Data Exchange (ETDEWEB)

    Boehling, Nicholas S. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Grosshans, David R., E-mail: dgrossha@mdanderson.org [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Bluett, Jaques B. [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Palmer, Matthew T. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Song, Xiaofei; Amos, Richard A.; Sahoo, Narayan [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Meyer, Jeffrey J.; Mahajan, Anita; Woo, Shiao Y. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

    2012-02-01

    Purpose: Cranial irradiation in pediatric patients is associated with serious long-term adverse effects. We sought to determine whether both three-dimensional conformal proton radiotherapy (3D-PRT) and intensity-modulated proton therapy (IMPT) compared with intensity-modulated radiotherapy (IMRT) decrease integral dose to brain areas known to harbor neuronal stem cells, major blood vessels, and other normal brain structures for pediatric patients with craniopharyngiomas. Methods and Materials: IMRT, forward planned, passive scattering proton, and IMPT plans were generated and optimized for 10 pediatric patients. The dose was 50.4 Gy (or cobalt Gy equivalent) delivered in 28 fractions with the requirement for planning target volume (PTV) coverage of 95% or better. Integral dose data were calculated from differential dose-volume histograms. Results: The PTV target coverage was adequate for all modalities. IMRT and IMPT yielded the most conformal plans in comparison to 3D-PRT. Compared with IMRT, 3D-PRT and IMPT plans had a relative reduction of integral dose to the hippocampus (3D-PRT, 20.4; IMPT, 51.3%{sup Asterisk-Operator }), dentate gyrus (27.3, 75.0%{sup Asterisk-Operator }), and subventricular zone (4.5, 57.8%{sup Asterisk-Operator }). Vascular organs at risk also had reduced integral dose with the use of proton therapy (anterior cerebral arteries, 33.3{sup Asterisk-Operator }, 100.0%{sup Asterisk-Operator }; middle cerebral arteries, 25.9%{sup Asterisk-Operator }, 100%{sup Asterisk-Operator }; anterior communicating arteries, 30.8{sup Asterisk-Operator }, 41.7%{sup Asterisk-Operator }; and carotid arteries, 51.5{sup Asterisk-Operator }, 77.6{sup Asterisk-Operator }). Relative reduction of integral dose to the infratentorial brain (190.7{sup Asterisk-Operator }, 109.7%{sup Asterisk-Operator }), supratentorial brain without PTV (9.6, 26.8%{sup Asterisk-Operator }), brainstem (45.6, 22.4%{sup Asterisk-Operator }), and whole brain without PTV (19.4{sup Asterisk

  8. Recent developments and comprehensive evaluations of a GPU-based Monte Carlo package for proton therapy

    Science.gov (United States)

    Qin, Nan; Botas, Pablo; Giantsoudi, Drosoula; Schuemann, Jan; Tian, Zhen; Jiang, Steve B.; Paganetti, Harald; Jia, Xun

    2016-10-01

    Monte Carlo (MC) simulation is commonly considered as the most accurate dose calculation method for proton therapy. Aiming at achieving fast MC dose calculations for clinical applications, we have previously developed a graphics-processing unit (GPU)-based MC tool, gPMC. In this paper, we report our recent updates on gPMC in terms of its accuracy, portability, and functionality, as well as comprehensive tests on this tool. The new version, gPMC v2.0, was developed under the OpenCL environment to enable portability across different computational platforms. Physics models of nuclear interactions were refined to improve calculation accuracy. Scoring functions of gPMC were expanded to enable tallying particle fluence, dose deposited by different particle types, and dose-averaged linear energy transfer (LETd). A multiple counter approach was employed to improve efficiency by reducing the frequency of memory writing conflict at scoring. For dose calculation, accuracy improvements over gPMC v1.0 were observed in both water phantom cases and a patient case. For a prostate cancer case planned using high-energy proton beams, dose discrepancies in beam entrance and target region seen in gPMC v1.0 with respect to the gold standard tool for proton Monte Carlo simulations (TOPAS) results were substantially reduced and gamma test passing rate (1%/1 mm) was improved from 82.7%-93.1%. The average relative difference in LETd between gPMC and TOPAS was 1.7%. The average relative differences in the dose deposited by primary, secondary, and other heavier particles were within 2.3%, 0.4%, and 0.2%. Depending on source proton energy and phantom complexity, it took 8-17 s on an AMD Radeon R9 290x GPU to simulate {{10}7} source protons, achieving less than 1% average statistical uncertainty. As the beam size was reduced from 10  ×  10 cm2 to 1  ×  1 cm2, the time on scoring was only increased by 4.8% with eight counters, in contrast to a 40% increase using only

  9. SU-E-J-49: Distal Edge Activity Fall Off Of Proton Therapy Beams

    Energy Technology Data Exchange (ETDEWEB)

    Elmekawy, A; Ewell, L [Hampton University, Hampton, VA (United States); Butuceanu, C; Zhu, L [HUPTI, Hampton, VA (United States)

    2014-06-01

    Purpose: To characterize and quantify the distal edge activity fall off, created in a phantom by a proton therapy beam Method and Materials: A 30x30x10cm polymethylmethacrylate phantom was irradiated with a proton therapy beam using different ranges and beams. The irradiation volume is approximated by a right circular cylinder of diameter 7.6cm and varying lengths. After irradiation, the phantom was scanned via a Philips Gemini Big Bore™ PET-CT for isotope activation. Varian Eclipse™ treatment planning system as well as ImageJ™ were used to analyze the resulting PET and CT scans. The region of activity within the phantom was longitudinally measured as a function of PET slice number. Dose estimations were made via Monte Carlo (GATE) simulation. Results: For both the spread out Bragg peak (SOBP) and the mono-energetic pristine Bragg peak proton beams, the proximal activation rise was steep: average slope −0.735 (average intensity/slice number) ± 0.091 (standard deviation) for the pristine beams and −1.149 ± 0.117 for the SOBP beams. In contrast, the distal fall offs were dissimilar. The distal fall off in activity for the pristine beams was fit well by a linear curve: R{sup 2} (Pierson Product) was 0.9968, 0.9955 and 0.9909 for the 13.5, 17.0 and 21.0cm range beams respectively. The good fit allows for a slope comparison between the different ranges. The slope varied as a function of range from 1.021 for the 13.5cm beam to 0.8407 (average intensity/slice number) for the 21.0cm beam. This dependence can be characterized: −0.0234(average intensity/slice number/cm range). For the SOBP beams, the slopes were significantly less and were also less linear: average slope 0.2628 ± 0.0474, average R{sup 2}=0.9236. Conclusion: The distal activation fall off edge for pristine proton beams was linear and steep. The corresponding quantities for SOBP beams were shallower and less linear. Philips has provided support for this work.

  10. SU-E-T-369: Evaluating Intensity Modulated Proton Therapy Relative to Passive Scattering Proton Therapy for Increased Vertebral Column Sparing in CSI of Pediatric Patients

    Energy Technology Data Exchange (ETDEWEB)

    Seco, J; Giantsoudi, D; Eaton, BR; Adams, JA; Paganetti, H; MacDonald, S [Harvard Medical School and Massachusetts General Hospital, Boston, MA (United States)

    2015-06-15

    Purpose: To investigate the trade-off between vertebral column sparing and thecal-sac target coverage in craniospinal irradiation (CSI) of pediatric patients treated with passive-scattering (PS) and intensity modulated (IMPT) proton therapy. Methods: We selected 2 pediatric patients treated with PS CSI for medulloblastoma. Spinal irradiation was re-planned with IMPT. For all cases, we assumed prescription dose of 23.4 Gy(RBE), with the spinal canal receiving at least 95% of 23.4 Gy(RBE). PS planning was performed using the commercial system XiO. IMPT planning was done using the Astroid planning system. Beam arrangements consisted of (a) PS posterior-anterior (PA) field, PS-PA, (b) IMPT PA field, IMPT-PA, and (c) two posterior oblique IMPT fields, IMPT2 (-35°, 35°). Dose distributions were re-calculated using TOPAS Monte Carlo, along with LET distributions, to investigate LET variations within the target and vertebra anatomy. Variable RBE-weighed dose distributions were also calculated based on a dose and LET-dependent biophysical model. Dosimetric data were compared among the plans for the target volume, spinal cord and adjacent critical organs (thecal-sac and cauda equina). Results: IMPT2 resulted in better sparing of the posterior vertebral column (entrance region posterior to thecal-sac), where planned dose was approximately 6–8Gy(RBE). For IMPT-PA and PS-PA the MC-calculated dose to the posterior vertebral column was, on average, 20Gy and 18Gy respectively. For IMPT2 higher mean-LET (5keV/µm/(g/cm3)) values were observed in anterior vertebral column (beyond the thecal-sac) relative to IMPT-PA and PS-PA, where mean-LET was 3.5keV/µm/(g/cm3) and 2.5keV/µm/(g/cm3) respectively. The higher LET region observed for both IMPT plans was in the distal end of treatment fields, where dose delivered was less 5Gy(RBE). Conclusion: The two-oblique proton beams IMPT2 best spared the spinal column, while reducing the dose to the posterior spinal column from 18–20 to 6

  11. SU-C-204-02: Improved Patient-Specific Optimization of the Stopping Power Calibration for Proton Therapy Planning Using a Single Proton Radiography

    Energy Technology Data Exchange (ETDEWEB)

    Rinaldi, I [Lyon 1 University and CNRS/IN2P3, UMR 5822, Villeurbanne (France); Ludwig Maximilian University, Garching, DE (Germany); Heidelberg University Hospital, Heidelberg, DE (Germany); Parodi, K [Ludwig Maximilian University, Garching, DE (Germany); Heidelberg University Hospital, Heidelberg, DE (Germany); Krah, N [Heidelberg Collaboratory for Image Processing, Heidelberg, DE (Germany)

    2015-06-15

    Purpose: We present an improved method to calculate patient-specific calibration curves to convert X-ray computed tomography (CT) Hounsfield Unit (HU) to relative stopping powers (RSP) for proton therapy treatment planning. Methods: By optimizing the HU-RSP calibration curve, the difference between a proton radiographic image and a digitally reconstructed X-ray radiography (DRR) is minimized. The feasibility of this approach has previously been demonstrated. This scenario assumes that all discrepancies between proton radiography and DRR originate from uncertainties in the HU-RSP curve. In reality, external factors cause imperfections in the proton radiography, such as misalignment compared to the DRR and unfaithful representation of geometric structures (“blurring”). We analyze these effects based on synthetic datasets of anthropomorphic phantoms and suggest an extended optimization scheme which explicitly accounts for these effects. Performance of the method is been tested for various simulated irradiation parameters. The ultimate purpose of the optimization is to minimize uncertainties in the HU-RSP calibration curve. We therefore suggest and perform a thorough statistical treatment to quantify the accuracy of the optimized HU-RSP curve. Results: We demonstrate that without extending the optimization scheme, spatial blurring (equivalent to FWHM=3mm convolution) in the proton radiographies can cause up to 10% deviation between the optimized and the ground truth HU-RSP calibration curve. Instead, results obtained with our extended method reach 1% or better correspondence. We have further calculated gamma index maps for different acceptance levels. With DTA=0.5mm and RD=0.5%, a passing ratio of 100% is obtained with the extended method, while an optimization neglecting effects of spatial blurring only reach ∼90%. Conclusion: Our contribution underlines the potential of a single proton radiography to generate a patient-specific calibration curve and to improve

  12. The Mobius AIRO mobile CT for image-guided proton therapy: Characterization & commissioning.

    Science.gov (United States)

    Oliver, Jasmine A; Zeidan, Omar A; Meeks, Sanford L; Shah, Amish P; Pukala, Jason; Kelly, Patrick; Ramakrishna, Naren R; Willoughby, Twyla R

    2017-05-01

    The purpose of this study was to characterize the Mobius AIRO Mobile CT System for localization and image-guided proton therapy. This is the first known application of the AIRO for proton therapy. Five CT images of a Catphan(®) 504 phantom were acquired on the AIRO Mobile CT System, Varian EDGE radiosurgery system cone beam CT (CBCT), Philips Brilliance Big Bore 16 slice CT simulator, and Siemens SOMATOM Definition AS 20 slice CT simulator. DoseLAB software v.6.6 was utilized for image quality analysis. Modulation transfer function, scaling discrepancy, geometric distortion, spatial resolution, overall uniformity, minimum uniformity, contrast, high CNR, and maximum HU deviation were acquired. Low CNR was acquired manually using the CTP515 module. Localization accuracy and CT Dose Index were measured and compared to reported values on each imaging device. For treatment delivery systems (Edge and Mevion), the localization accuracy of the 3D imaging systems were compared to 2D imaging systems on each system. The AIRO spatial resolution was 0.21 lp mm(-1) compared with 0.40 lp mm(-1) for the Philips CT Simulator, 0.37 lp mm(-1) for the Edge CBCT, and 0.35 lp mm(-1) for the Siemens CT Simulator. AIRO/Siemens and AIRO/Philips differences exceeded 100% for scaling discrepancy (191.2% and 145.8%). The AIRO exhibited higher dose (>27 mGy) than the Philips CT Simulator. Localization accuracy (based on the MIMI phantom) was 0.6° and 0.5 mm. Localization accuracy (based on Stereophan) demonstrated maximum AIRO-kV/kV shift differences of 0.1 mm in the x-direction, 0.1 mm in the y-direction, and 0.2 mm in the z-direction. The localization accuracy of AIRO was determined to be within 0.6° and 0.5 mm despite its slightly lower image quality overall compared to other CT imaging systems at our institution. Based on our study, the Mobile AIRO CT system can be utilized accurately and reliably for image-guided proton therapy. © 2017 The Authors. Journal of Applied Clinical Medical

  13. SU-E-J-139: One Institution’s Experience with Surface Imaging in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, L; Singh, H; Zheng, Y [ProCure Proton Therapy Center, Oklahoma City, OK (United States)

    2015-06-15

    Purpose: X-ray system is commonly used for IGRT in proton therapy, however image acquisition not only increases treatment time but also adds imaging dose. We studied a 3D surface camera system (AlignRT) performance for proton therapy. Methods: System accuracy was evaluated with rigid phantom under two different camera location configurations. For initial clinical applications, post mastectomy chest wall and partial breast treatments were studied. X-ray alignment was used as our ground truth. Our studies included: 1) comparison of daily patient setup shifts between X-ray alignment and SI calculation; 2) interfractional breast surface position variation when aligning to bony landmark on X-ray; 3) absolute positioning using planning CT DICOM data; 4) shifts for multi-isocenter treatment plan; 5) couch isocentric rotation accuracy. Results: Camera locations affected the system performance. After camera relocation, the accuracy of the system for the rigid phantom was within 1 mm (fixed couch), and 1.5 mm (isocentric rotation). For intrafractional patient positioning, X-ray and AlignRT shifts were highly correlated (r=0.99), with the largest difference (mean ± SD) in the longitudinal direction (2.14 ± 1.02 mm). For interfractional breast surface variation and absolute positioning, there were still larger disagreements between the two modalities due to different focus on anatomical landmarks, and 95% of the data lie within 5mm with some outliers at 7 mm–9 mm. For multi-isocenter shifts, the difference was 1 ± 0.56 mm over an 11 cm shift in longitudinal direction. For couch rotation study, the differences was 1.36 ± 1.0 mm in vertical direction, 3.04 ± 2.11 mm in longitudinal direction, and 2.10 ± 1.66 mm in lateral direction, with all rotation differences < 1.5 degree. Conclusion: Surface imaging is promising for intrafractional treatment application in proton therapy to reduce X-ray frequency. However the interfractional discrepancy between the X-ray and SI

  14. Optimizing the modified microdosimetric kinetic model input parameters for proton and 4He ion beam therapy application

    Science.gov (United States)

    Mairani, A.; Magro, G.; Tessonnier, T.; Böhlen, T. T.; Molinelli, S.; Ferrari, A.; Parodi, K.; Debus, J.; Haberer, T.

    2017-06-01

    Models able to predict relative biological effectiveness (RBE) values are necessary for an accurate determination of the biological effect with proton and 4He ion beams. This is particularly important when including RBE calculations in treatment planning studies comparing biologically optimized proton and 4He ion beam plans. In this work, we have tailored the predictions of the modified microdosimetric kinetic model (MKM), which is clinically applied for carbon ion beam therapy in Japan, to reproduce RBE with proton and 4He ion beams. We have tuned the input parameters of the MKM, i.e. the domain and nucleus radii, reproducing an experimental database of initial RBE data for proton and He ion beams. The modified MKM, with the best fit parameters obtained, has been used to reproduce in vitro cell survival data in clinically-relevant scenarios. A satisfactory agreement has been found for the studied cell lines, A549 and RENCA, with the mean absolute survival variation between the data and predictions within 2% and 5% for proton and 4He ion beams, respectively. Moreover, a sensitivity study has been performed varying the domain and nucleus radii and the quadratic parameter of the photon response curve. The promising agreement found in this work for the studied clinical-like scenarios supports the usage of the modified MKM for treatment planning studies in proton and 4He ion beam therapy.

  15. A Novel Approach to Postmastectomy Radiation Therapy Using Scanned Proton Beams

    Energy Technology Data Exchange (ETDEWEB)

    Depauw, Nicolas, E-mail: ndepauw@partners.org [Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Centre for Medical Radiation Physics, University of Wollongong, New South Wales (Australia); Batin, Estelle; Daartz, Julianne [Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Rosenfeld, Anatoly [Centre for Medical Radiation Physics, University of Wollongong, New South Wales (Australia); Adams, Judith; Kooy, Hanne; MacDonald, Shannon; Lu, Hsiao-Ming [Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2015-02-01

    Purpose: Postmastectomy radiation therapy (PMRT), currently offered at Massachusetts General Hospital, uses proton pencil beam scanning (PBS) with intensity modulation, achieving complete target coverage of the chest wall and all nodal regions and reduced dose to the cardiac structures. This work presents the current methodology for such treatment and the ongoing effort for its improvements. Methods and Materials: A single PBS field is optimized to ensure appropriate target coverage and heart/lung sparing, using an in–house-developed proton planning system with the capability of multicriteria optimization. The dose to the chest wall skin is controlled as a separate objective in the optimization. Surface imaging is used for setup because it is a suitable surrogate for superficial target volumes. In order to minimize the effect of beam range uncertainties, the relative proton stopping power ratio of the material in breast implants was determined through separate measurements. Phantom measurements were also made to validate the accuracy of skin dose calculation in the treatment planning system. Additionally, the treatment planning robustness was evaluated relative to setup perturbations and patient breathing motion. Results: PBS PMRT planning resulted in appropriate target coverage and organ sparing, comparable to treatments by passive scattering (PS) beams but much improved in nodal coverage and cardiac sparing compared to conventional treatments by photon/electron beams. The overall treatment time was much shorter than PS and also shorter than conventional photon/electron treatment. The accuracy of the skin dose calculation by the planning system was within ±2%. The treatment was shown to be adequately robust relative to both setup uncertainties and patient breathing motion, resulting in clinically satisfying dose distributions. Conclusions: More than 25 PMRT patients have been successfully treated at Massachusetts General Hospital by using single-PBS fields

  16. Towards Achieving the Full Clinical Potential of Proton Therapy by Inclusion of LET and RBE Models

    Directory of Open Access Journals (Sweden)

    Bleddyn Jones

    2015-03-01

    Full Text Available Despite increasing use of proton therapy (PBT, several systematic literature reviews show limited gains in clinical outcomes, with publications mostly devoted to recent technical developments. The lack of randomised control studies has also hampered progress in the acceptance of PBT by many oncologists and policy makers. There remain two important uncertainties associated with PBT, namely: (1 accuracy and reproducibility of Bragg peak position (BPP; and (2 imprecise knowledge of the relative biological effect (RBE for different tissues and tumours, and at different doses. Incorrect BPP will change dose, linear energy transfer (LET and RBE, with risks of reduced tumour control and enhanced toxicity. These interrelationships are discussed qualitatively with respect to the ICRU target volume definitions. The internationally accepted proton RBE of 1.1 was based on assays and dose ranges unlikely to reveal the complete range of RBE in the human body. RBE values are not known for human (or animal brain, spine, kidney, liver, intestine, etc. A simple efficiency model for estimating proton RBE values is described, based on data of Belli et al. and other authors, which allows linear increases in α and β with LET, with a gradient estimated using a saturation model from the low LET α and β radiosensitivity parameter input values, and decreasing RBE with increasing dose. To improve outcomes, 3-D dose-LET-RBE and bio-effectiveness maps are required. Validation experiments are indicated in relevant tissues. Randomised clinical studies that test the invariant 1.1 RBE allocation against higher values in late reacting tissues, and lower tumour RBE values in the case of radiosensitive tumours, are also indicated.

  17. Towards Achieving the Full Clinical Potential of Proton Therapy by Inclusion of LET and RBE Models

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Bleddyn [Gray Laboratory, CRUK/MRC Oxford Oncology Institute, The University of Oxford, ORCRB-Roosevelt Drive, Oxford OX3 7DQ (United Kingdom)

    2015-03-17

    Despite increasing use of proton therapy (PBT), several systematic literature reviews show limited gains in clinical outcomes, with publications mostly devoted to recent technical developments. The lack of randomised control studies has also hampered progress in the acceptance of PBT by many oncologists and policy makers. There remain two important uncertainties associated with PBT, namely: (1) accuracy and reproducibility of Bragg peak position (BPP); and (2) imprecise knowledge of the relative biological effect (RBE) for different tissues and tumours, and at different doses. Incorrect BPP will change dose, linear energy transfer (LET) and RBE, with risks of reduced tumour control and enhanced toxicity. These interrelationships are discussed qualitatively with respect to the ICRU target volume definitions. The internationally accepted proton RBE of 1.1 was based on assays and dose ranges unlikely to reveal the complete range of RBE in the human body. RBE values are not known for human (or animal) brain, spine, kidney, liver, intestine, etc. A simple efficiency model for estimating proton RBE values is described, based on data of Belli et al. and other authors, which allows linear increases in α and β with LET, with a gradient estimated using a saturation model from the low LET α and β radiosensitivity parameter input values, and decreasing RBE with increasing dose. To improve outcomes, 3-D dose-LET-RBE and bio-effectiveness maps are required. Validation experiments are indicated in relevant tissues. Randomised clinical studies that test the invariant 1.1 RBE allocation against higher values in late reacting tissues, and lower tumour RBE values in the case of radiosensitive tumours, are also indicated.

  18. Comparative study: Vonoprazan and proton pump inhibitors in Helicobacter pylori eradication therapy

    Science.gov (United States)

    Sakurai, Kouichi; Suda, Hiroko; Ido, Yumi; Takeichi, Takayuki; Okuda, Ayako; Hasuda, Kiwamu; Hattori, Masahiro

    2017-01-01

    AIM To compare the effectiveness and safety of vonoprazan-based therapy with proton pump inhibitor (PPI)-based therapies to treat Helicobacter pylori (H. pylori). METHODS We retrospectively analysed data from first-line (vonoprazan or PPI with 200 mg clarithromycin and 750 mg amoxicillin twice daily for 7 d) (n = 1353) and second-line (vonoprazan or PPI with 250 mg metronidazole and 750 mg amoxicillin twice daily for 7 d) (n = 261) eradication treatments for H. pylori -positive patients with associated gastrointestinal diseases from April 2014 to December 2015 at Hattori Clinic, Japan. The primary endpoint was the eradication rate, which was assessed with a full analysis set. The secondary endpoints were adverse events and related factors. RESULTS After the first-line treatments, the eradication rates for vonoprazan, esomeprazol, rabeprazole, and lansoprazole were 87.9% (95%CI: 84.9%-90.5%), 71.6% (95%CI: 67.5%-75.5%), 62.9% (95%CI: 52.0%-72.9%), and 57.3% (95%CI: 50.4%-64.1%), respectively. The vonoprazan eradication rate was significantly higher than that of the PPIs (P pylori eradication rate in the vonoprazan group (P = 0.34), whereas it decreased the rates in the PPI groups (P = 0.013). The incidence of adverse events in the vonoprazan group was not different from the PPI group (P = 0.054), although the vonoprazan group exhibited a wider range of adverse events. Vonoprazan-based triple therapy was highly effective as a second-line treatment, with an eradication rate similar to that of PPI-based therapy. CONCLUSION Vonoprazan might be superior to PPIs in first-line H. pylori therapy, particularly for smokers. However, caution is required due to possible adverse events. PMID:28216974

  19. Measurements of spatial distribution of absorbed dose in proton therapy with Gafchromic EBT3

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G.; Regazzoni, V.; Grisotto, S.; Artuso, E.; Giove, D. [Universita degli Studi di Milano, Department of Physics, via Celoria 16, 20133 Milano (Italy); Borroni, M.; Carrara, M.; Pignoli, E. [Fondazione IRCCS, Istituto Nazionale dei Tumori di Milano, Medical Physics Unit, via Giacomo Venezian 16, 20133 Milano (Italy); Mirandola, A.; Ciocca, M., E-mail: grazia.gambarini@mi.infn.it [Centro Nazionale Adroterapia Oncologica, Medical Physics Unit, Strada Campeggi 53, 27100 Pavia (Italy)

    2014-08-15

    A study of the response of EBT3 films has been carried out. Light transmittance images (around 630 nm) were acquired by means of a Ccd camera. The difference of optical density was assumed as dosimeter response. Calibration was performed by means of {sup 60}Co photons, at a radiotherapy facility. A study of the response variation during the time after exposure has been carried out. EBT3 films were exposed, in a solid-water phantom, to proton beams of various energies and the obtained depth-dose profiles were compared with those measured with a ionization chamber. As expected, in the Bragg peak region the values obtained with EBT3 films were lower than those obtained with the ionization chamber. The ratio of such values was evaluated, along dose profiles, for each utilized energy. A method for correcting the data measured with EBT3 has been proposed and tested. The results confirm that the method can be advantageously applied for obtaining spatial distribution of the absorbed dose in proton therapy. (author)

  20. Laser acceleration of protons from near critical density targets for application to radiation therapy

    CERN Document Server

    Bulanov, S S; Pirozhkov, A S; Thomas, A G R; Willingale, L; Krushelnick, K; Maksimchuk, A

    2010-01-01

    Laser accelerated protons can be a complimentary source for treatment of oncological diseases to the existing hadron therapy facilities. We demonstrate how the protons, accelerated from near-critical density plasmas by laser pulses having relatively small power, reach energies which may be of interest for medical applications. When an intense laser pulse interacts with near-critical density plasma it makes a channel both in the electron and then in the ion density. The propagation of a laser pulse through such a self-generated channel is connected with the acceleration of electrons in the wake of a laser pulse and generation of strong moving electric and magnetic fields in the propagation channel. Upon exiting the plasma the magnetic field generates a quasi-static electric field that accelerates and collimates ions from a thin filament formed in the propagation channel. Two-dimensional Particle-in-Cell simulations show that a 100 TW laser pulse tightly focused on a near-critical density target is able to acce...

  1. Physician Evaluation of Internet Health Information on Proton Therapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Anand, E-mail: as4351@columbia.edu [Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Department of Radiation Oncology, Columbia University Medical Center, New York, New York (United States); Paly, Jonathan J.; Efstathiou, Jason A. [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (United States); Bekelman, Justin E. [Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia, Pennsylvania (United States)

    2013-03-15

    Purpose: Many patients considering prostate cancer (PCa) treatment options report seeking proton beam therapy (PBT) based in part on information readily available on the Internet. There is, however, potential for considerable variation in Internet health information (IHI). We thus evaluated the characteristics, quality, and accuracy of IHI on PBT for PCa. Methods and Materials: We undertook a qualitative research study using snowball-purposive sampling in which we evaluated the top 50 Google search results for “proton prostate cancer.” Quality was evaluated on a 5-point scale using the validated 15-question DISCERN instrument. Accuracy was evaluated by comparing IHI with the best available evidence. Results: Thirty-seven IHI websites were included in the final sample. These websites most frequently were patient information/support resources (46%), were focused exclusively on PBT (51%), and had a commercial affiliation (38%). There was a significant difference in quality according to the type of IHI. Substantial inaccuracies were noted in the study sample compared with best available or contextual evidence. Conclusions: There are shortcomings in quality and accuracy in consumer-oriented IHI on PBT for PCa. Providers must be prepared to educate patients how to critically evaluate IHI related to PBT for PCa to best inform their treatment decisions.

  2. Donut-shaped high-dose configuration for proton beam radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Rutz, H.P.; Lomax, A.J. [Div. of Radiation Medicine, Paul Scherrer Inst., Villigen PSI (Switzerland)

    2005-01-01

    Background: the authors report on the conception and first clinical application of a donut-shaped high-dose configuration for proton therapy (PT). This approach allows one to intensify target volume dose coverage for targets encompassing a critical, dose-limiting structure - like here, the cauda equina -, whilst delivering minimal dose to other healthy structures surrounding the target, thereby reducing the integral dose. Methods and results: intensity-modulated PT methods (IMPT) for spot scanning were applied to create and deliver a donut-shaped high-dose configuration with protons, allowing treating > 75% of the target with at least 95% of the prescribed dose of 72.8 CGE, whilst restricting dose to the cauda equina to 60-65 CGE. Integral dose was lower by a factor of 3.3 as compared to intensity-modulated radiotherapy with photons (IMXT). Conclusion: IMPT and spot scanning technology allow a potentially clinically useful approach which is also applicable to spare other critical structures passing through a target volume, including spinal cord, optic nerves, chiasm, brain stem, or urethra. (orig.)

  3. Chromatic energy filter and characterization of laser-accelerated proton beams for particle therapy

    Science.gov (United States)

    Hofmann, Ingo; Meyer-ter-Vehn, Jürgen; Yan, Xueqing; Al-Omari, Husam

    2012-07-01

    The application of laser accelerated protons or ions for particle therapy has to cope with relatively large energy and angular spreads as well as possibly significant random fluctuations. We suggest a method for combined focusing and energy selection, which is an effective alternative to the commonly considered dispersive energy selection by magnetic dipoles. Our method is based on the chromatic effect of a magnetic solenoid (or any other energy dependent focusing device) in combination with an aperture to select a certain energy width defined by the aperture radius. It is applied to an initial 6D phase space distribution of protons following the simulation output from a Radiation Pressure Acceleration model. Analytical formula for the selection aperture and chromatic emittance are confirmed by simulation results using the TRACEWIN code. The energy selection is supported by properly placed scattering targets to remove the imprint of the chromatic effect on the beam and to enable well-controlled and shot-to-shot reproducible energy and transverse density profiles.

  4. Validation of a track repeating algorithm for intensity modulated proton therapy: clinical cases study

    Science.gov (United States)

    Yepes, Pablo P.; Eley, John G.; Liu, Amy; Mirkovic, Dragan; Randeniya, Sharmalee; Titt, Uwe; Mohan, Radhe

    2016-04-01

    Monte Carlo (MC) methods are acknowledged as the most accurate technique to calculate dose distributions. However, due its lengthy calculation times, they are difficult to utilize in the clinic or for large retrospective studies. Track-repeating algorithms, based on MC-generated particle track data in water, accelerate dose calculations substantially, while essentially preserving the accuracy of MC. In this study, we present the validation of an efficient dose calculation algorithm for intensity modulated proton therapy, the fast dose calculator (FDC), based on a track-repeating technique. We validated the FDC algorithm for 23 patients, which included 7 brain, 6 head-and-neck, 5 lung, 1 spine, 1 pelvis and 3 prostate cases. For validation, we compared FDC-generated dose distributions with those from a full-fledged Monte Carlo based on GEANT4 (G4). We compared dose-volume-histograms, 3D-gamma-indices and analyzed a series of dosimetric indices. More than 99% of the voxels in the voxelized phantoms describing the patients have a gamma-index smaller than unity for the 2%/2 mm criteria. In addition the difference relative to the prescribed dose between the dosimetric indices calculated with FDC and G4 is less than 1%. FDC reduces the calculation times from 5 ms per proton to around 5 μs.

  5. A new PET prototype for proton therapy: comparison of data and Monte Carlo simulations

    Science.gov (United States)

    Rosso, V.; Battistoni, G.; Belcari, N.; Camarlinghi, N.; Ferrari, A.; Ferretti, S.; Kraan, A.; Mairani, A.; Marino, N.; Ortuño, J. E.; Pullia, M.; Sala, P.; Santos, A.; Sportelli, G.; Straub, K.; Del Guerra, A.

    2013-03-01

    Ion beam therapy is a valuable method for the treatment of deep-seated and radio-resistant tumors thanks to the favorable depth-dose distribution characterized by the Bragg peak. Hadrontherapy facilities take advantage of the specific ion range, resulting in a highly conformal dose in the target volume, while the dose in critical organs is reduced as compared to photon therapy. The necessity to monitor the delivery precision, i.e. the ion range, is unquestionable, thus different approaches have been investigated, such as the detection of prompt photons or annihilation photons of positron emitter nuclei created during the therapeutic treatment. Based on the measurement of the induced β+ activity, our group has developed various in-beam PET prototypes: the one under test is composed by two planar detector heads, each one consisting of four modules with a total active area of 10 × 10 cm2. A single detector module is made of a LYSO crystal matrix coupled to a position sensitive photomultiplier and is read-out by dedicated frontend electronics. A preliminary data taking was performed at the Italian National Centre for Oncological Hadron Therapy (CNAO, Pavia), using proton beams in the energy range of 93-112 MeV impinging on a plastic phantom. The measured activity profiles are presented and compared with the simulated ones based on the Monte Carlo FLUKA package.

  6. Minibeam Therapy With Protons and Light Ions: Physical Feasibility and Potential to Reduce Radiation Side Effects and to Facilitate Hypofractionation

    Energy Technology Data Exchange (ETDEWEB)

    Dilmanian, F. Avraham, E-mail: avraham.dilmanian@stonybrook.edu [Departments of Radiation Oncology, Neurology, and Radiology, Stony Brook University Medical Center, Stony Brook, New York (United States); Eley, John G. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Krishnan, Sunil [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2015-06-01

    Purpose: Despite several advantages of proton therapy over megavoltage x-ray therapy, its lack of proximal tissue sparing is a concern. The method presented here adds proximal tissue sparing to protons and light ions by turning their uniform incident beams into arrays of parallel, small, or thin (0.3-mm) pencil or planar minibeams, which are known to spare tissues. As these minibeams penetrate the tissues, they gradually broaden and merge with each other to produce a solid beam. Methods and Materials: Broadening of 0.3-mm-diameter, 109-MeV proton pencil minibeams was measured using a stack of radiochromic films with plastic spacers. Monte Carlo simulations were used to evaluate the broadening in water of minibeams of protons and several light ions and the dose from neutron generated by collimator. Results: A central parameter was tissue depth, where the beam full width at half maximum (FWHM) reached 0.7 mm, beyond which tissue sparing decreases. This depth was 22 mm for 109-MeV protons in a film stack. It was also found by simulations in water to be 23.5 mm for 109 MeV proton pencil minibeams and 26 mm for 116 MeV proton planar minibeams. For light ions, all with 10 cm range in water, that depth increased with particle size; specifically it was 51 mm for Li-7 ions. The ∼2.7% photon equivalent neutron skin dose from the collimator was reduced 7-fold by introducing a gap between the collimator and the skin. Conclusions: Proton minibeams can be implemented at existing particle therapy centers. Because they spare the shallow tissues, they could augment the efficacy of proton therapy and light particle therapy, particularly in treating tumors that benefit from sparing of proximal tissues such as pediatric brain tumors. They should also allow hypofractionated treatment of all tumors by allowing the use of higher incident doses with less concern about proximal tissue damage.

  7. Proton beam therapy for pediatric malignancies: a retrospective observational multicenter study in Japan.

    Science.gov (United States)

    Mizumoto, Masashi; Murayama, Shigeyuki; Akimoto, Tetsuo; Demizu, Yusuke; Fukushima, Takashi; Ishida, Yuji; Oshiro, Yoshiko; Numajiri, Haruko; Fuji, Hiroshi; Okumura, Toshiyuki; Shirato, Hiroki; Sakurai, Hideyuki

    2016-07-01

    Recent progress in the treatment for pediatric malignancies using a combination of surgery, chemotherapy, and radiotherapy has improved survival. However, late toxicities of radiotherapy are a concern in long-term survivors. A recent study suggested reduced secondary cancer and other late toxicities after proton beam therapy (PBT) due to dosimetric advantages. In this study, we evaluated the safety and efficacy of PBT for pediatric patients treated in Japan. A retrospective observational study in pediatric patients who received PBT was performed. All patients aged loss (two cases), cerebral vascular disease, and tissue necrosis occurred in five patients. This study provides preliminary results for PBT in pediatric patients in Japan. More experience and follow-up with this technique are required to establish the efficacy of PBT in this patient population.

  8. Virtual commissioning of a treatment planning system for proton therapy of ocular cancers.

    Science.gov (United States)

    Koch, N; Newhauser, W

    2005-01-01

    The virtual commissioning of a treatment planning system (TPS) for ocular proton beam therapy was performed using Monte Carlo (MC) simulations and a model of a double-scattering ocular treatment nozzle. The simulations produced both the input data required by the TPS and the dose distributions to validate the analytical predictions from the TPS. An MC simulation of a typical ocular melanoma treatment was compared with the TPS predictions, revealing generally good agreement in the absorbed dose distribution. However, in the depth-dose profiles, differences >5% existed in the proximal region of all validation cases considered. Comparison of the radiation coverage at or above the 90% dose level, showed that MC calculated coverage was 82% and 68% of the coverage calculated by the TPS in two planes intersecting the tumour.

  9. Stereotactic body radiation therapy (SBRT) for adrenal metastases. A feasibility study of advanced techniques with modulated photons and protons

    Energy Technology Data Exchange (ETDEWEB)

    Mancosu, Pietro; Navarria, Piera; Tozzi, Angelo; Castiglioni, Simona; Clerici, Elena; Reggiori, Giacomo; Lobefalo, Francesca [Istituto Clinico Humanitas, Rozzano-Milan (Italy). Dept. of Radiation Oncology; Fogliata, Antonella; Cozzi, Luca [Oncology Institute of Southern Switzerland, Bellinzona (Switzerland). Medical Physics Unit; Scorsetti, Marta

    2011-04-15

    Purpose: To compare advanced treatment techniques with photons and protons as a stereotactic body radiation therapy (SBRT) for adrenal glands metastases. Materials and Methods: Planning computer tomographic (CT) scans of 10 patients were selected. A total dose of 45 Gy in 7.5 Gy fractions was prescribed. Organs at risk (OAR) were liver and kidneys. Dose-volume metrics were defined to quantify quality of plans assessing target coverage and sparing of organs at risk. Plans for RapidArc, intensity-modulated radiotherapy (IMRT), dynamic conformal arcs, 3D conformal static fields, and intensity modulated protons were compared. The main planning objective for the clinical target volume (CTV) was to cover 100% of the volume with 95% (V{sub 95%} = 100%) and to keep the maximum dose below 107% of the prescribed dose (V{sub 107%} = 0%). Planning objective for planning target volume (PTV) was V{sub 95%} > 80%. For kidneys, the general planning objective was V{sub 15Gy} < 35% and for liver V{sub 15Gy} < (liver volume-700 cm{sup 3}). Results: All techniques achieved the minimum and maximum dose objective for CTV and PTV, D{sub 5-95%} ranged from 1 Gy (protons) to 1.6 Gy (conformal static fields) on CTV. Maximal organ at risk sparing was achieved by protons. RapidArc presented the second lowest dose bath (V{sub 10Gy} and integral dose) after protons and the best conformality together with IMRT. Conclusions: Stereotactic body radiation therapy (SBRT) to adrenal glands metastases is achievable with several advanced techniques with either photons or protons. The intensity modulated approaches using either static fields, dynamic arcs or protons are superior to the other conformal solutions. For their simplicity, IMRT or RapidArc should be considered as the first option radiation treatment for those patients not eligible for proton treatment. (orig.)

  10. SU-E-J-78: Adaptive Planning Workflow in a Pencil Beam Scanning Proton Therapy Center

    Energy Technology Data Exchange (ETDEWEB)

    Blakey, M; Price, S; Robison, B; Niek, S; Moe, S; Renegar, J; Mark, A; Spenser, W [Provision Healthcare Partners, Knoxville, TN (United States)

    2015-06-15

    Purpose: The susceptibility of proton therapy to changes in patient setup and anatomy necessitates an adaptive planning process. With the right planning tools and clinical workflow, an adaptive plan can be created in a timely manner without adding significant workload to the treatment planning staff. Methods: In our center, a weekly QA CT is performed on most patients to assess setup, anatomy change, and tumor response. The QA CT is fused to the treatment planning CT, the contours are transferred via deformable registration, and the plan dose is recalculated on the QA CT. A physicist assesses the dose distribution, and an adaptive plan is requested based on tumor coverage or OAR dose changes. After the physician confirms or alters the deformed contours, a dosimetrist develops an adaptive plan using our TPS adaptation module. The plan is assessed for robustness and is then reviewed by the physician. Patient QA is performed within three days following the first adapted treatment. Results: Of the patients who received QA CTs, 19% required at least one adaptive plan (18.5% H&N, 18.5% brain, 11.1% breast, 14.8% chestwall, 14.8% lung, 18.5% pelvis and 3.8% abdomen). Of these patients, 14% went on a break, while the remainder was treated with the previous plan during the re-planning process. Adaptive plans were performed based on tumor shrinkage, anatomy change or positioning uncertainties for 37.9%, 44.8%, and 17.3% of the patients, respectively. On average, 3 full days are required between the QA CT and the first adapted plan treatment. Conclusion: Adaptive planning is a crucial component of proton therapy and should be applied to any site when the QA CT shows significant deviation from the plan. With an efficient workflow, an adaptive plan can be applied without delaying patient treatment or burdening the dosimetry and medical physics team.

  11. Hip fractures and pain following proton therapy for management of prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Valery, Raul; Mendenhall, Nancy P.; Nichols, Romaine C. Jr.; Henderson, Randal; Morris, Christopher G.; Su, Zhong; Li, Zuofeng; Hoppe, Bradford S. [Univ. of Florida Proton Therapy Inst., Univ. of Florida Coll. of Medicine, Jacksonville (United States)], e-mail: bhoppe@floridaproton.org; Mendenhall, William M. [Dept. of Radiation Oncology, Coll. of Medicine, Univ. of Florida, Gainesville (United States); Williams, Christopher R. [Dept. of Surgery, Univ. of Florida Coll. of Medicine, Jacksonville (United States)

    2013-04-15

    Background: Proton therapy (PT) for prostate cancer reduces rectal and bladder dose, but increases dose to the femoral necks. We assessed the risk of hip fracture and pain in men treated with PT for prostate cancer. Material and methods: From 2006 to 2008, 382 men were treated for prostate cancer and evaluated at six-month intervals after PT for toxicities at Univ. of Florida Proton Therapy Institute (UFPTI). The WHO Fracture Risk Assessment Tool (FRAX) generated annual hip-fracture risk for the cohort. The WHO FRAX tool was utilized to generate the expected number of patients with hip fractures and the observed-to-expected ratio; confidence intervals and p-value were generated with the mid-P exact test. Univariate analysis of hip pain as a function of several prognostic factors was accomplished with Fisher's exact test. Results. Median follow-up was four years (range, 0.1-5.5 years). Per FRAX, 3.02 patients were expected to develop a hip fracture without PT. Three PT patients actually developed fractures for a rate of 0.21 fractures per 100 person-years of follow-up. There was an observed-expected ratio of 0.99 (p-value not significant). Forty-eight patients (13%) reported new pain in the hip during follow-up; three required prescription analgesics. Conclusion. PT for prostate cancer did not increase hip-fractures in the first four years after PT compared to expected rates in untreated men.

  12. In-beam PET imaging for on-line adaptive proton therapy: an initial phantom study

    Science.gov (United States)

    Shao, Yiping; Sun, Xishan; Lou, Kai; Zhu, Xiaorong R.; Mirkovic, Dragon; Poenisch, Falk; Grosshans, David

    2014-07-01

    We developed and investigated a positron emission tomography (PET) system for use with on-line (both in-beam and intra-fraction) image-guided adaptive proton therapy applications. The PET has dual rotating depth-of-interaction measurable detector panels by using solid-state photomultiplier (SSPM) arrays and LYSO scintillators. It has a 44 mm diameter trans-axial and 30 mm axial field-of-view (FOV). A 38 mm diameter polymethyl methacrylate phantom was placed inside the FOV. Both PET and phantom axes were aligned with a collimated 179.2 MeV beam. Each beam delivered ˜50 spills (0.5 s spill and 1.5 s inter-spill time, 3.8 Gy at Bragg peak). Data from each beam were acquired with detectors at a given angle. Nine datasets for nine beams with detectors at nine different angles over 180° were acquired for full-tomographic imaging. Each dataset included data both during and 5 min after irradiations. The positron activity-range was measured from the PET image reconstructed from all nine datasets and compared to the results from simulated images. A 22Na disc-source was also imaged after each beam to monitor the PET system's performance. PET performed well except for slight shifts of energy photo-peak positions (PET with high sensitivity and uniform resolution. Sub-mm activity-ranges were achieved with minimal 6 s acquisition time and three spill irradiations. These results indicate the feasibility of PET for intra-fraction beam-range verification. Further studies are needed to develop and apply a novel clinical PET system for on-line image-guided adaptive proton therapy.

  13. Investigation into the effects of high-Z nano materials in proton therapy

    Science.gov (United States)

    Ahmad, R.; Royle, G.; Lourenço, A.; Schwarz, M.; Fracchiolla, F.; Ricketts, K.

    2016-06-01

    High-Z nano materials have been previously shown to increase the amount of dose deposition within the tumour due to an increase in secondary electrons. This study evaluates the effects of high-Z nano materials in combination with protons, and the impact of proton energy, nanoparticle material and concentration. These effects were studied in silico through Monte Carlo simulation and experimentally through a phantom study, with particular attention to macroscale changes to the Bragg peak in the presence of nanoparticles. Three nanoparticle materials were simulated (gold, silver and platinum) at three concentrations (0.01, 0.1 and 6.5 mg ml-1) at two clinical proton energies (60 and 226 MeV). Simulations were verified experimentally using Gafchromic film measurements of gold nanoparticles suspended in water at two available high concentrations (5.5 mg ml-1 and 1.1 mg ml-1). A significant change to Bragg peak features was evident, where at 226 MeV and 6.5 mg ml-1, simulations of gold showed a 4.7 mm longitudinal shift of the distal edge and experimentally at 5.5 mg ml-1, a shift of 2.2 mm. Simulations showed this effect to be material dependent, where platinum having the highest physical density caused the greatest shift with increasing concentration. A dose enhancement of 6%  ±  0.05 and 5%  ±  0.15 (60 MeV and 226 MeV, respectively) was evident with gold at 6.5 mg ml-1 to water alone, compared to the 21%  ±  0.53 observed experimentally as dose to film with 5.5 mg ml-1 of gold nanoparticles suspended in water at 226 MeV. The introduction of nanoparticles has strong potential to enhance dose in proton therapy, however the changes to the Bragg peak distribution that occur with high concentrations need to be accounted for to ensure tumour coverage.

  14. An anthropomorphic breathing phantom of the thorax for testing new motion mitigation techniques for pencil beam scanning proton therapy

    NARCIS (Netherlands)

    Perrin, R L; Zakova, M; Peroni, Marta; Bernatowicz, K; Bikis, C; Knopf, A. K.; Safai, S; Fernandez-Carmona, P; Tscharner, N; Weber, Damien C.; Parkel, T C; Lomax, Antony J.

    2017-01-01

    Motion-induced range changes and incorrectly placed dose spots strongly affect the quality of pencil-beam-scanned (PBS) proton therapy, especially in thoracic tumour sites, where density changes are large. Thus motion-mitigation techniques are necessary, which must be validated in a realistic

  15. Monte Carlo modeling of proton therapy installations: a global experimental method to validate secondary neutron dose calculations.

    Science.gov (United States)

    Farah, J; Martinetti, F; Sayah, R; Lacoste, V; Donadille, L; Trompier, F; Nauraye, C; De Marzi, L; Vabre, I; Delacroix, S; Hérault, J; Clairand, I

    2014-06-07

    Monte Carlo calculations are increasingly used to assess stray radiation dose to healthy organs of proton therapy patients and estimate the risk of secondary cancer. Among the secondary particles, neutrons are of primary concern due to their high relative biological effectiveness. The validation of Monte Carlo simulations for out-of-field neutron doses remains however a major challenge to the community. Therefore this work focused on developing a global experimental approach to test the reliability of the MCNPX models of two proton therapy installations operating at 75 and 178 MeV for ocular and intracranial tumor treatments, respectively. The method consists of comparing Monte Carlo calculations against experimental measurements of: (a) neutron spectrometry inside the treatment room, (b) neutron ambient dose equivalent at several points within the treatment room, (c) secondary organ-specific neutron doses inside the Rando-Alderson anthropomorphic phantom. Results have proven that Monte Carlo models correctly reproduce secondary neutrons within the two proton therapy treatment rooms. Sensitive differences between experimental measurements and simulations were nonetheless observed especially with the highest beam energy. The study demonstrated the need for improved measurement tools, especially at the high neutron energy range, and more accurate physical models and cross sections within the Monte Carlo code to correctly assess secondary neutron doses in proton therapy applications.

  16. Monte Carlo modeling of proton therapy installations: a global experimental method to validate secondary neutron dose calculations

    Science.gov (United States)

    Farah, J.; Martinetti, F.; Sayah, R.; Lacoste, V.; Donadille, L.; Trompier, F.; Nauraye, C.; De Marzi, L.; Vabre, I.; Delacroix, S.; Hérault, J.; Clairand, I.

    2014-06-01

    Monte Carlo calculations are increasingly used to assess stray radiation dose to healthy organs of proton therapy patients and estimate the risk of secondary cancer. Among the secondary particles, neutrons are of primary concern due to their high relative biological effectiveness. The validation of Monte Carlo simulations for out-of-field neutron doses remains however a major challenge to the community. Therefore this work focused on developing a global experimental approach to test the reliability of the MCNPX models of two proton therapy installations operating at 75 and 178 MeV for ocular and intracranial tumor treatments, respectively. The method consists of comparing Monte Carlo calculations against experimental measurements of: (a) neutron spectrometry inside the treatment room, (b) neutron ambient dose equivalent at several points within the treatment room, (c) secondary organ-specific neutron doses inside the Rando-Alderson anthropomorphic phantom. Results have proven that Monte Carlo models correctly reproduce secondary neutrons within the two proton therapy treatment rooms. Sensitive differences between experimental measurements and simulations were nonetheless observed especially with the highest beam energy. The study demonstrated the need for improved measurement tools, especially at the high neutron energy range, and more accurate physical models and cross sections within the Monte Carlo code to correctly assess secondary neutron doses in proton therapy applications.

  17. Estimated radiation pneumonitis risk after photon versus proton therapy alone or combined with chemotherapy for lung cancer

    DEFF Research Database (Denmark)

    Vogelius, Ivan R.; Westerly, David C; Aznar, Marianne Camille

    2011-01-01

    -radiation combinations could be an interesting indication for selecting patients for proton therapy. It is likely that the IMRT plans would perform better if the CERD was accounted for during optimization, but more clinical data is required to facilitate evidence-based plan optimization in the multi-modality setting....

  18. Proton therapy of prostate cancer by anterior-oblique beams: implications of setup and anatomy variations

    Science.gov (United States)

    Moteabbed, M.; Trofimov, A.; Sharp, G. C.; Wang, Y.; Zietman, A. L.; Efstathiou, J. A.; Lu, H.-M.

    2017-03-01

    Proton therapy of prostate by anterior beams could offer an attractive option for treating patients with hip prosthesis and limiting the high-dose exposure to the rectum. We investigated the impact of setup and anatomy variations on the anterior-oblique (AO) proton plan dose, and strategies to manage these effects via range verification and adaptive delivery. Ten patients treated by bilateral (BL) passive-scattering proton therapy (79.2 Gy in 44 fractions) who underwent weekly verification CT scans were selected. Plans with AO beams were additionally created. To isolate the effect of daily variations, initial AO plans did not include range uncertainty margins. The use of fixed planning margins and adaptive range adjustments to manage these effects was investigated. For each case, the planned dose was recalculated on weekly CTs, and accumulated on the simulation CT using deformable registration to approximate the delivered dose. Planned and accumulated doses were compared for each scenario to quantify dose deviations induced by variations. The possibility of estimating the necessary range adjustments before each treatment was explored by simulating the procedure of a diode-based in vivo range verification technique, which would potentially be used clinically. The average planned rectum, penile bulb and femoral heads mean doses were smaller for initial AO compared to BL plans (by 8.3, 16.1 and 25.9 Gy, respectively). After considering interfractional variations in AO plans, the target coverage was substantially reduced. The maximum reduction of V 79.2/D 95/D mean/EUD for AO (without distal margins) (25.3%/10.7/1.6/4.9 Gy, respectively) was considerably larger than BL plans. The loss of coverage was mainly related to changes in water equivalent path length of the prostate after fiducial-based setup, caused by discrepancies in patient anterior surface and bony-anatomy alignment. Target coverage was recovered partially when using fixed planning margins, and fully when

  19. Dosimetric feasibility of real-time MRI-guided proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Moteabbed, M., E-mail: mmoteabbed@partners.org; Schuemann, J.; Paganetti, H. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States)

    2014-11-01

    Purpose: Magnetic resonance imaging (MRI) is a prime candidate for image-guided radiotherapy. This study was designed to assess the feasibility of real-time MRI-guided proton therapy by quantifying the dosimetric effects induced by the magnetic field in patients’ plans and identifying the associated clinical consequences. Methods: Monte Carlo dose calculation was performed for nine patients of various treatment sites (lung, liver, prostate, brain, skull-base, and spine) and tissue homogeneities, in the presence of 0.5 and 1.5 T magnetic fields. Dose volume histogram (DVH) parameters such as D{sub 95}, D{sub 5}, and V{sub 20} as well as equivalent uniform dose were compared for the target and organs at risk, before and after applying the magnetic field. The authors further assessed whether the plans affected by clinically relevant dose distortions could be corrected independent of the planning system. Results: By comparing the resulting dose distributions and analyzing the respective DVHs, it was determined that despite the observed lateral beam deflection, for magnetic fields of up to 0.5 T, neither was the target coverage jeopardized nor was the dose to the nearby organs increased in all cases except for prostate. However, for a 1.5 T magnetic field, the dose distortions were more pronounced and of clinical concern in all cases except for spine. In such circumstances, the target was severely underdosed, as indicated by a decrease in D{sub 95} of up to 41% of the prescribed dose compared to the nominal situation (no magnetic field). Sites such as liver and spine were less affected due to higher tissue homogeneity, typically smaller beam range, and the choice of beam directions. Simulations revealed that small modifications to certain plan parameters such as beam isocenter (up to 19 mm) and gantry angle (up to 10°) are sufficient to compensate for the magnetic field-induced dose disturbances. The authors’ observations indicate that the degree of required

  20. Feasibility of pancreatectomy following high-dose proton therapy for unresectable pancreatic cancer

    Science.gov (United States)

    Hitchcock, Kathryn E; Nichols, R Charles; Morris, Christopher G; Bose, Debashish; Hughes, Steven J; Stauffer, John A; Celinski, Scott A; Johnson, Elizabeth A; Zaiden, Robert A; Mendenhall, Nancy P; Rutenberg, Michael S

    2017-01-01

    AIM To review surgical outcomes for patients undergoing pancreatectomy after proton therapy with concomitant capecitabine for initially unresectable pancreatic adenocarcinoma. METHODS From April 2010 to September 2013, 15 patients with initially unresectable pancreatic cancer were treated with proton therapy with concomitant capecitabine at 1000 mg orally twice daily. All patients received 59.40 Gy (RBE) to the gross disease and 1 patient received 50.40 Gy (RBE) to high-risk nodal targets. There were no treatment interruptions and no chemotherapy dose reductions. Six patients achieved a radiographic response sufficient to justify surgical exploration, of whom 1 was identified as having intraperitoneal dissemination at the time of surgery and the planned pancreatectomy was aborted. Five patients underwent resection. Procedures included: Laparoscopic standard pancreaticoduodenectomy (n = 3), open pyloris-sparing pancreaticoduodenectomy (n = 1), and open distal pancreatectomy with irreversible electroporation (IRE) of a pancreatic head mass (n = 1). RESULTS The median patient age was 60 years (range, 51-67). The median duration of surgery was 419 min (range, 290-484), with a median estimated blood loss of 850 cm3 (range, 300-2000), median ICU stay of 1 d (range, 0-2), and median hospital stay of 10 d (range, 5-14). Three patients were re-admitted to a hospital within 30 d after discharge for wound infection (n = 1), delayed gastric emptying (n = 1), and ischemic gastritis (n = 1). Two patients underwent R0 resections and demonstrated minimal residual disease in the final pathology specimen. One patient, after negative pancreatic head biopsies, underwent IRE followed by distal pancreatectomy with no tumor seen in the specimen. Two patients underwent R2 resections. Only 1 patient demonstrated ultimate local progression at the primary site. Median survival for the 5 resected patients was 24 mo (range, 10-30). CONCLUSION Pancreatic resection for patients with initially

  1. A comprehensive spectrometry study of a stray neutron radiation field in scanning proton therapy

    Science.gov (United States)

    Mares, Vladimir; Romero-Expósito, Maite; Farah, Jad; Trinkl, Sebastian; Domingo, Carles; Dommert, Martin; Stolarczyk, Liliana; Van Ryckeghem, Laurent; Wielunski, Marek; Olko, Pawel; Harrison, Roger M.

    2016-06-01

    The purpose of this study is to characterize the stray neutron radiation field in scanning proton therapy considering a pediatric anthropomorphic phantom and a clinically-relevant beam condition. Using two extended-range Bonner sphere spectrometry systems (ERBSS), Working Group 9 of the European Radiation Dosimetry Group measured neutron spectra at ten different positions around a pediatric anthropomorphic phantom irradiated for a brain tumor with a scanning proton beam. This study compares the different systems and unfolding codes as well as neutron spectra measured in similar conditions around a water tank phantom. The ten spectra measured with two ERBSS systems show a generally similar thermal component regardless of the position around the phantom while high energy neutrons (above 20 MeV) were only registered at positions near the beam axis (at 0°, 329° and 355°). Neutron spectra, fluence and ambient dose equivalent, H *(10), values of both systems were in good agreement (<15%) while the unfolding code proved to have a limited effect. The highest H *(10) value of 2.7 μSv Gy-1 was measured at 329° to the beam axis and 1.63 m from the isocenter where high-energy neutrons (E  ⩾  20 MeV) contribute with about 53%. The neutron mapping within the gantry room showed that H *(10) values significantly decreased with distance and angular position with respect to the beam axis dropping to 0.52 μSv Gy-1 at 90° and 3.35 m. Spectra at angles of 45° and 135° with respect to the beam axis measured here with an anthropomorphic phantom showed a similar peak structure at the thermal, fast and high energy range as in the previous water-tank experiments. Meanwhile, at 90°, small differences at the high-energy range were observed. Using ERBSS systems, neutron spectra mapping was performed to characterize the exposure of scanning proton therapy patients. The ten measured spectra provide precise information about the exposure of healthy organs to thermal

  2. Range optimization for mono- and bi-energetic proton modulated arc therapy with pencil beam scanning

    Science.gov (United States)

    Sanchez-Parcerisa, Daniel; Kirk, Maura; Fager, Marcus; Burgdorf, Brendan; Stowe, Malorie; Solberg, Tim; Carabe, Alejandro

    2016-11-01

    The development of rotational proton therapy plans based on a pencil-beam-scanning (PBS) system has been limited, among several other factors, by the energy-switching time between layers, a system-dependent parameter that ranges between a fraction of a second and several seconds. We are investigating mono- and bi-energetic rotational proton modulated arc therapy (PMAT) solutions that would not be affected by long energy switching times. In this context, a systematic selection of the optimal proton energy for each arc is vital. We present a treatment planning comparison of four different range selection methods, analyzing the dosimetric outcomes of the resulting treatment plans created with the ranges obtained. Given the patient geometry and arc definition (gantry and couch trajectories, snout elevation) our in-house treatment planning system (TPS) FoCa was used to find the maximum, medial and minimum water-equivalent thicknesses (WETs) of the target viewed from all possible field orientations. Optimal ranges were subsequently determined using four methods: (1) by dividing the max/min WET interval into equal steps, (2) by taking the average target midpoints from each field, (3) by taking the average WET of all voxels from all field orientations, and (4) by minimizing the fraction of the target which cannot be reached from any of the available angles. After the range (for mono-energetic plans) or ranges (for bi-energetic plans) were selected, the commercial clinical TPS in use in our institution (Varian Eclipse™) was used to produce the PMAT plans using multifield optimization. Linear energy transfer (LET) distributions of all plans were also calculated using FoCa and compared among the different methods. Mono- and bi-energetic PMAT plans, composed of a single 180° arc, were created for two patient geometries: a C-shaped target located in the mediastinal area of a thoracic tissue-equivalent phantom and a small brain tumor located directly above the brainstem. All

  3. Optimization of dual-energy CT acquisitions for proton therapy using projection-based decomposition.

    Science.gov (United States)

    Vilches-Freixas, Gloria; Létang, Jean Michel; Ducros, Nicolas; Rit, Simon

    2017-09-01

    Dual-energy computed tomography (DECT) has been presented as a valid alternative to single-energy CT to reduce the uncertainty of the conversion of patient CT numbers to proton stopping power ratio (SPR) of tissues relative to water. The aim of this work was to optimize DECT acquisition protocols from simulations of X-ray images for the treatment planning of proton therapy using a projection-based dual-energy decomposition algorithm. We have investigated the effect of various voltages and tin filtration combinations on the SPR map accuracy and precision, and the influence of the dose allocation between the low-energy (LE) and the high-energy (HE) acquisitions. For all spectra combinations, virtual CT projections of the Gammex phantom were simulated with a realistic energy-integrating detector response model. Two situations were simulated: an ideal case without noise (infinite dose) and a realistic situation with Poisson noise corresponding to a 20 mGy total central dose. To determine the optimal dose balance, the proportion of LE-dose with respect to the total dose was varied from 10% to 90% while keeping the central dose constant, for four dual-energy spectra. SPR images were derived using a two-step projection-based decomposition approach. The ranges of 70 MeV, 90 MeV, and 100 MeV proton beams onto the adult female (AF) reference computational phantom of the ICRP were analytically determined from the reconstructed SPR maps. The energy separation between the incident spectra had a strong impact on the SPR precision. Maximizing the incident energy gap reduced image noise. However, the energy gap was not a good metric to evaluate the accuracy of the SPR. In terms of SPR accuracy, a large variability of the optimal spectra was observed when studying each phantom material separately. The SPR accuracy was almost flat in the 30-70% LE-dose range, while the precision showed a minimum slightly shifted in favor of lower LE-dose. Photon noise in the SPR images (20 mGy dose

  4. Design study of an in situ PET scanner for use in proton beam therapy

    Energy Technology Data Exchange (ETDEWEB)

    Surti, S; Daube-Witherspoon, M E; Karp, J S [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Zou, W; McDonough, J, E-mail: surti@mail.med.upenn.edu [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104 (United States)

    2011-05-07

    Proton beam therapy can deliver a high radiation dose to a tumor without significant damage to surrounding healthy tissue or organs. One way of verifying the delivered dose distribution is to image the short-lived positron emitters produced by the proton beam as it travels through the patient. A potential solution to the limitations of PET imaging in proton beam therapy is the development of a high sensitivity, in situ PET scanner that starts PET imaging almost immediately after patient irradiation while the patient is still lying on the treatment bed. A partial ring PET design is needed for this application in order to avoid interference between the PET detectors and the proton beam, as well as restrictions on patient positioning on the couch. A partial ring also allows us to optimize the detector separation (and hence the sensitivity) for different patient sizes. Our goal in this investigation is to evaluate an in situ PET scanner design for use in proton therapy that provides tomographic imaging in a partial ring scanner design using time-of-flight (TOF) information and an iterative reconstruction algorithm. GEANT4 simulation of an incident proton beam was used to produce a positron emitter distribution, which was parameterized and then used as the source distribution inside a water-filled cylinder for EGS4 simulations of a PET system. Design optimization studies were performed as a function of crystal type and size, system timing resolution, scanner angular coverage and number of positron emitter decays. Data analysis was performed to measure the accuracy of the reconstructed positron emitter distribution as well as the range of the positron emitter distribution. We simulated scanners with varying crystal sizes (2-4 mm) and type (LYSO and LaBr{sub 3}) and our results indicate that 4 mm wide LYSO or LaBr{sub 3} crystals (resulting in 4-5 mm spatial resolution) are adequate; for a full-ring, non-TOF scanner we predict a low bias (<0.6 mm) and a good precision (<1

  5. Design study of an in situ PET scanner for use in proton beam therapy

    Science.gov (United States)

    Surti, S.; Zou, W.; Daube-Witherspoon, M. E.; McDonough, J.; Karp, J. S.

    2011-05-01

    Proton beam therapy can deliver a high radiation dose to a tumor without significant damage to surrounding healthy tissue or organs. One way of verifying the delivered dose distribution is to image the short-lived positron emitters produced by the proton beam as it travels through the patient. A potential solution to the limitations of PET imaging in proton beam therapy is the development of a high sensitivity, in situ PET scanner that starts PET imaging almost immediately after patient irradiation while the patient is still lying on the treatment bed. A partial ring PET design is needed for this application in order to avoid interference between the PET detectors and the proton beam, as well as restrictions on patient positioning on the couch. A partial ring also allows us to optimize the detector separation (and hence the sensitivity) for different patient sizes. Our goal in this investigation is to evaluate an in situ PET scanner design for use in proton therapy that provides tomographic imaging in a partial ring scanner design using time-of-flight (TOF) information and an iterative reconstruction algorithm. GEANT4 simulation of an incident proton beam was used to produce a positron emitter distribution, which was parameterized and then used as the source distribution inside a water-filled cylinder for EGS4 simulations of a PET system. Design optimization studies were performed as a function of crystal type and size, system timing resolution, scanner angular coverage and number of positron emitter decays. Data analysis was performed to measure the accuracy of the reconstructed positron emitter distribution as well as the range of the positron emitter distribution. We simulated scanners with varying crystal sizes (2-4 mm) and type (LYSO and LaBr3) and our results indicate that 4 mm wide LYSO or LaBr3 crystals (resulting in 4-5 mm spatial resolution) are adequate; for a full-ring, non-TOF scanner we predict a low bias (<0.6 mm) and a good precision (<1 mm) in the

  6. Imaging Changes in Pediatric Intracranial Ependymoma Patients Treated With Proton Beam Radiation Therapy Compared to Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gunther, Jillian R. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Sato, Mariko; Chintagumpala, Murali [Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Texas Children' s Cancer Center, Houston, Texas (United States); Ketonen, Leena [Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Jones, Jeremy Y. [Department of Pediatric Radiology, Texas Children' s Hospital, Houston, Texas (United States); Allen, Pamela K. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Paulino, Arnold C. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Texas Children' s Cancer Center, Houston, Texas (United States); Okcu, M. Fatih; Su, Jack M. [Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Texas Children' s Cancer Center, Houston, Texas (United States); Weinberg, Jeffrey [Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Boehling, Nicholas S. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Khatua, Soumen [Department of Pediatrics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Adesina, Adekunle [Department of Pathology, Baylor College of Medicine, Texas Children' s Hospital, Houston, Texas (United States); Dauser, Robert; Whitehead, William E. [Department of Neurosurgery, Texas Children' s Hospital, Houston, Texas (United States); Mahajan, Anita, E-mail: amahajan@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2015-09-01

    Purpose: The clinical significance of magnetic resonance imaging (MRI) changes after radiation therapy (RT) in children with ependymoma is not well defined. We compared imaging changes following proton beam radiation therapy (PBRT) to those after photon-based intensity modulated RT (IMRT). Methods and Materials: Seventy-two patients with nonmetastatic intracranial ependymoma who received postoperative RT (37 PBRT, 35 IMRT) were analyzed retrospectively. MRI images were reviewed by 2 neuroradiologists. Results: Sixteen PBRT patients (43%) developed postradiation MRI changes at 3.8 months (median) with resolution by 6.1 months. Six IMRT patients (17%) developed changes at 5.3 months (median) with 8.3 months to resolution. Mean age at radiation was 4.4 and 6.9 years for PBRT and IMRT, respectively (P=.06). Age at diagnosis (>3 years) and time of radiation (≥3 years) was associated with fewer imaging changes on univariate analysis (odds ratio [OR]: 0.35, P=.048; OR: 0.36, P=.05). PBRT (compared to IMRT) was associated with more frequent imaging changes, both on univariate (OR: 3.68, P=.019) and multivariate (OR: 3.89, P=.024) analyses. Seven (3 IMRT, 4 PBRT) of 22 patients with changes had symptoms requiring intervention. Most patients were treated with steroids; some PBRT patients also received bevacizumab and hyperbaric oxygen therapy. None of the IMRT patients had lasting deficits, but 2 patients died from recurrent disease. Three PBRT patients had persistent neurological deficits, and 1 child died secondarily to complications from radiation necrosis. Conclusions: Postradiation MRI changes are more common with PBRT and in patients less than 3 years of age at diagnosis and treatment. It is difficult to predict causes for development of imaging changes that progress to clinical significance. These changes are usually self-limiting, but some require medical intervention, especially those involving the brainstem.

  7. Recommendations for the referral of patients for proton-beam therapy, an Alberta Health Services report: a model for Canada?

    Science.gov (United States)

    Patel, S.; Kostaras, X.; Parliament, M.; Olivotto, I.A.; Nordal, R.; Aronyk, K.; Hagen, N.

    2014-01-01

    Background Compared with photon therapy, proton-beam therapy (pbt) offers compelling advantages in physical dose distribution. Worldwide, gantry-based proton facilities are increasing in number, but no such facilities exist in Canada. To access pbt, Canadian patients must travel abroad for treatment at high cost. In the face of limited access, this report seeks to provide recommendations for the selection of patients most likely to benefit from pbt and suggests an out-of-country referral process. Methods The medline, embase, PubMed, and Cochrane databases were systematically searched for studies published between January 1990 and May 2014 that evaluated clinical outcomes after pbt. A draft report developed through a review of evidence was externally reviewed and then approved by the Alberta Health Services Cancer Care Proton Therapy Guidelines steering committee. Results Proton therapy is often used to treat tumours close to radiosensitive tissues and to treat children at risk of developing significant late effects of radiation therapy (rt). In uncontrolled and retrospective studies, local control rates with pbt appear similar to, or in some cases higher than, photon rt. Randomized trials comparing equivalent doses of pbt and photon rt are not available. Summary Referral for pbt is recommended for patients who are being treated with curative intent and with an expectation for long-term survival, and who are able and willing to travel abroad to a proton facility. Commonly accepted indications for referral include chordoma and chondrosarcoma, intraocular melanoma, and solid tumours in children and adolescents who have the greatest risk for long-term sequelae. Current data do not provide sufficient evidence to recommend routine referral of patients with most head-and-neck, breast, lung, gastrointestinal tract, and pelvic cancers, including prostate cancer. It is recommended that all referrals be considered by a multidisciplinary team to select appropriate cases. PMID

  8. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams

    Science.gov (United States)

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-01

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing 22Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy.

  9. Evaluation of the local dose enhancement in the combination of proton therapy and nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Rovira, I., E-mail: immamartinez@gmail.com; Prezado, Y. [Laboratoire d’Imagerie et Modélisation en Neurobiologie et Cancérologie (IMNC), Centre National de la Recherche Scientifique (CNRS), Université Paris 7 and 11, Campus Universitaire, Bât. 440, 1er étage, 15 rue Georges Clemenceau, Orsay Cedex 91406 (France)

    2015-11-15

    Purpose: The outcome of radiotherapy can be further improved by combining irradiation with dose enhancers such as high-Z nanoparticles. Since 2004, spectacular results have been obtained when low-energy x-ray irradiations have been combined with nanoparticles. Recently, the same combination has been explored in hadron therapy. In vitro studies have shown a significant amplification of the biological damage in tumor cells charged with nanoparticles and irradiated with fast ions. This has been attributed to the increase in the ionizations and electron emissions induced by the incident ions or the electrons in the secondary tracks on the high-Z atoms, resulting in a local energy deposition enhancement. However, this subject is still a matter of controversy. Within this context, the main goal of the authors’ work was to provide new insights into the dose enhancement effects of nanoparticles in proton therapy. Methods: For this purpose, Monte Carlo calculations (GATE/GEANT4 code) were performed. In particular, the GEANT4-DNA toolkit, which allows the modeling of early biological damages induced by ionizing radiation at the DNA scale, was used. The nanometric radial energy distributions around the nanoparticle were studied, and the processes (such as Auger deexcitation or dissociative electron attachment) participating in the dose deposition of proton therapy treatments in the presence of nanoparticles were evaluated. It has been reported that the architecture of Monte Carlo calculations plays a crucial role in the assessment of nanoparticle dose enhancement and that it may introduce a bias in the results or amplify the possible final dose enhancement. Thus, a dosimetric study of different cases was performed, considering Au and Gd nanoparticles, several nanoparticle sizes (from 4 to 50 nm), and several beam configurations (source-nanoparticle distances and source sizes). Results: This Monte Carlo study shows the influence of the simulations’ parameters on the local

  10. A phenomenological relative biological effectiveness approach for proton therapy based on an improved description of the mixed radiation field

    Science.gov (United States)

    Mairani, A.; Dokic, I.; Magro, G.; Tessonnier, T.; Bauer, J.; Böhlen, T. T.; Ciocca, M.; Ferrari, A.; Sala, P. R.; Jäkel, O.; Debus, J.; Haberer, T.; Abdollahi, A.; Parodi, K.

    2017-02-01

    Proton therapy treatment planning systems (TPSs) are based on the assumption of a constant relative biological effectiveness (RBE) of 1.1 without taking into account the found in vitro experimental variations of the RBE as a function of tissue type, linear energy transfer (LET) and dose. The phenomenological RBE models available in literature are based on the dose-averaged LET (LET D ) as an indicator of the physical properties of the proton radiation field. The LET D values are typically calculated taking into account primary and secondary protons, neglecting the biological effect of heavier secondaries. In this work, we have introduced a phenomenological RBE approach which considers the biological effect of primary protons, and of secondary protons, deuterons, tritons (Z  =  1) and He fragments (3He and 4He, Z  =  2). The calculation framework, coupled with a Monte Carlo (MC) code, has been successfully benchmarked against clonogenic in vitro data measured in this work for two cell lines and then applied to determine biological quantities for spread-out Bragg peaks and a prostate and a head case. The introduced RBE formalism, which depends on the mixed radiation field, the dose and the ratio of the linear–quadratic model parameters for the reference radiation {{≤ft(α /β \\right)}\\text{ph}} , predicts, when integrated in an MC code, higher RBE values in comparison to LET D -based parameterizations. This effect is particular enhanced in the entrance channel of the proton field and for low {{≤ft(α /β \\right)}\\text{ph}} tissues. For the prostate and the head case, we found higher RBE-weighted dose values up to about 5% in the entrance channel when including or neglecting the Z  =  2 secondaries in the RBE calculation. TPSs able to proper account for the mixed radiation field in proton therapy are thus recommended for an accurate determination of the RBE in the whole treatment field.

  11. Comparison of Out-Of-Field Neutron Equivalent Doses in Scanning Carbon and Proton Therapies for Cranial Fields

    DEFF Research Database (Denmark)

    Athar, B.; Henker, K.; Jäkel, O.

    Purpose: The purpose of this analysis is to compare the secondary neutron lateral doses from scanning carbon and proton beam therapies. Method and Materials: We simulated secondary neutron doses for out-of-field organs in an 11-year old male patient. Scanned carbon and proton beams were simulated...... separately using Monte Carlo techniques. We have used circular aperture field of 6 cm in diameter as a representative field. The tumor was assumed to be in the cranium. The range and modulation width for both carbon and proton beams were set to 15 cm and 10 cm, respectively. Results: In carbon therapy......, absorbed neutron doses to tonsils and pharynx close to the field-edge were found to be 5x10-4 mSv/GyE and 4x10-4 mSv/GyE, respectively. Whereas, neutron equivalent doses to tonsils and pharynx were estimated to be 0.57mSv/GyE and 0.55 mSv/GyE in scanned proton therapy, respectively. In heavy ion carbon...

  12. Comparison of Out-Of-Field Neutron Equivalent Doses in Scanning Carbon and Proton Therapies for Cranial Fields

    DEFF Research Database (Denmark)

    Athar, B.; Henker, K.; Jäkel, O.;

    Purpose: The purpose of this analysis is to compare the secondary neutron lateral doses from scanning carbon and proton beam therapies. Method and Materials: We simulated secondary neutron doses for out-of-field organs in an 11-year old male patient. Scanned carbon and proton beams were simulated...... separately using Monte Carlo techniques. We have used circular aperture field of 6 cm in diameter as a representative field. The tumor was assumed to be in the cranium. The range and modulation width for both carbon and proton beams were set to 15 cm and 10 cm, respectively. Results: In carbon therapy......, absorbed neutron doses to tonsils and pharynx close to the field-edge were found to be 5x10-4 mSv/GyE and 4x10-4 mSv/GyE, respectively. Whereas, neutron equivalent doses to tonsils and pharynx were estimated to be 0.57mSv/GyE and 0.55 mSv/GyE in scanned proton therapy, respectively. In heavy ion carbon...

  13. Involved-Node Proton Therapy in Combined Modality Therapy for Hodgkin Lymphoma: Results of a Phase 2 Study

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, Bradford S., E-mail: bhoppe@floridaproton.org [Radiation Oncology, University of Florida Proton Therapy Institute, Jacksonville, Florida (United States); Flampouri, Stella [Radiation Oncology, University of Florida Proton Therapy Institute, Jacksonville, Florida (United States); Zaiden, Robert [Department of Medicine, Division of Hematology and Oncology, University of Florida College of Medicine, Jacksonville, Florida (United States); Slayton, William [Department of Pediatrics, Division of Hematology and Oncology, University of Florida College of Medicine, Gainesville, Florida (United States); Sandler, Eric [Department of Pediatrics, Division of Hematology/Oncology Nemours Children' s Clinic, Jacksonville, Florida (United States); Ozdemir, Savas [Department of Radiology, Division of Functional and Molecular Imaging, University of Florida College of Medicine, Jacksonville, Florida (United States); Dang, Nam H.; Lynch, James W. [Department of Medicine, Division of Hematology and Oncology, University of Florida College of Medicine, Gainesville, Florida (United States); Li, Zuofeng; Morris, Christopher G.; Mendenhall, Nancy P. [Radiation Oncology, University of Florida Proton Therapy Institute, Jacksonville, Florida (United States)

    2014-08-01

    Purpose: This study describes the early clinical outcomes of a prospective phase 2 study of consolidative involved-node proton therapy (INPT) as a component of combined-mode therapy in patients with stages I to III Hodgkin lymphoma (HL) with mediastinal involvement. Methods and Materials: Between September 2009 and June 2013, 15 patients with newly diagnosed HL received INPT after completing chemotherapy in an institutional review board-approved protocol comparing the dosimetric impact of PT with those of three-dimensional conformal radiation therapy (3DCRT) and intensity modulated RT. Based on {sup 18}F-Fluorodeoxyglucose positron emission tomography/computed tomography ({sup 18}F-FDG PET/CT) response, 5 children received 15 to 25.5 cobalt Gy equivalent (CGE) of INPT after receiving 4 cycles of Adriamycin, Bleomycin, Vincristine, Etoposide, Prednisone, Cyclophosphamide or Vincristine, adriamycin, methotrexate, Prednisone chemotherapy, and 10 adults received 30.6 to 39.6 CGE of INPT after 3 to 6 cycles of Adriamycin, Bleomycine, Vinblastine, Dacarbazine. Patients were routinely evaluated for toxicity during and after treatment, using Common Terminology Criteria for Adverse Events, version 3.0, and for relapse by physical examination and routine imaging. Relapse-free survival (RFS) and event-free survival (EFS) rates were calculated using the Kaplan-Meier method from the time of diagnosis. Results: The median follow-up was 37 months (range, 26-55). Two events occurred during follow-up: 1 relapse (inside and outside the targeted field) and 1 transformation into a primary mediastinal large B cell lymphoma. The 3-year RFS rate was 93%, and the 3-year EFS rate was 87%. No acute or late grade 3 nonhematologic toxicities were observed. Conclusions: Although decades of follow-up will be needed to realize the likely benefit of PT in reducing the risk of radiation-induced late effects, PT following chemotherapy in patients with HL is well-tolerated, and disease outcomes

  14. Assessment of radiation-induced second cancer risks in proton therapy and IMRT for organs inside the primary radiation field.

    Science.gov (United States)

    Paganetti, Harald; Athar, Basit S; Moteabbed, Maryam; A Adams, Judith; Schneider, Uwe; Yock, Torunn I

    2012-10-07

    There is clinical evidence that second malignancies in radiation therapy occur mainly within the beam path, i.e. in the medium or high-dose region. The purpose of this study was to assess the risk for developing a radiation-induced tumor within the treated volume and to compare this risk for proton therapy and intensity-modulated photon therapy (IMRT). Instead of using data for specific patients we have created a representative scenario. Fully contoured age- and gender-specific whole body phantoms (4 year and 14 year old) were uploaded into a treatment planning system and tumor volumes were contoured based on patients treated for optic glioma and vertebral body Ewing's sarcoma. Treatment plans for IMRT and proton therapy treatments were generated. Lifetime attributable risks (LARs) for developing a second malignancy were calculated using a risk model considering cell kill, mutation, repopulation, as well as inhomogeneous organ doses. For standard fractionation schemes, the LAR for developing a second malignancy from radiation therapy alone was found to be up to 2.7% for a 4 year old optic glioma patient treated with IMRT considering a soft-tissue carcinoma risk model only. Sarcoma risks were found to be below 1% in all cases. For a 14 year old, risks were found to be about a factor of 2 lower. For Ewing's sarcoma cases the risks based on a sarcoma model were typically higher than the carcinoma risks, i.e. LAR up to 1.3% for soft-tissue sarcoma. In all cases, the risk from proton therapy turned out to be lower by at least a factor of 2 and up to a factor of 10. This is mainly due to lower total energy deposited in the patient when using proton beams. However, the comparison of a three-field and four-field proton plan also shows that the distribution of the dose, i.e. the particular treatment plan, plays a role. When using different fractionation schemes, the estimated risks roughly scale with the total dose difference in%. In conclusion, proton therapy can

  15. Fast pencil beam dose calculation for proton therapy using a double-Gaussian beam model

    Directory of Open Access Journals (Sweden)

    Joakim eda Silva

    2015-12-01

    Full Text Available The highly conformal dose distributions produced by scanned proton pencil beams are more sensitive to motion and anatomical changes than those produced by conventional radiotherapy. The ability to calculate the dose in real time as it is being delivered would enable, for example, online dose monitoring, and is therefore highly desirable. We have previously described an implementation of a pencil beam algorithm running on graphics processing units (GPUs intended specifically for online dose calculation. Here we present an extension to the dose calculation engine employing a double-Gaussian beam model to better account for the low-dose halo. To the best of our knowledge, it is the first such pencil beam algorithm for proton therapy running on a GPU. We employ two different parametrizations for the halo dose, one describing the distribution of secondary particles from nuclear interactions found in the literature and one relying on directly fitting the model to Monte Carlo simulations of pencil beams in water. Despite the large width of the halo contribution, we show how in either case the second Gaussian can be included whilst prolonging the calculation of the investigated plans by no more than 16%, or the calculation of the most time-consuming energy layers by about 25%. Further, the calculation time is relatively unaffected by the parametrization used, which suggests that these results should hold also for different systems. Finally, since the implementation is based on an algorithm employed by a commercial treatment planning system, it is expected that with adequate tuning, it should be able to reproduce the halo dose from a general beam line with sufficient accuracy.

  16. Effect of tissue heterogeneity on an in vivo range verification technique for proton therapy

    Science.gov (United States)

    Hassane Bentefour, El; Shikui, Tang; Prieels, Damien; Lu, Hsiao-Ming

    2012-09-01

    It was proposed recently that time-resolved dose measurements during proton therapy treatment by passively scattered beams may be used for in vivo range verification. The method was shown to work accurately in a water tank. In this paper, we further evaluated the potential of the method for more clinically relevant situations where proton beams must pass through regions with significant tissue heterogeneities. Specifically, we considered prostate treatment where the use of anterior or anterior- oblique fields was recently proposed in order to reduce rectal dose by taking advantage of the sharp distal fall-off of the Bragg peak. These beam portals pass through various parts of pubic bone and potential air cavities in the bladder and bowels. Using blocks of materials with densities equivalent to bone, air, etc, arranged in the water tank in relevant configurations, we tested the robustness of the method against range shifting and range mixing. In the former, the beam range is changed uniformly by changes in tissue density in the beam path, while in the latter, variations in tissue heterogeneities across the beam cross section causes the mixing of beam energies downstream, as often occurs when the beam travels along the interface of materials with significantly different densities. We demonstrated that in the region of interest, the method can measure water-equivalent path length with accuracy better than ±0.5 mm for pure range shifting and still reasonable accuracy for range mixing between close beam energies. In situations with range mixing between significantly different beam energies, the dose rate profiles may be simulated for verifying the beam range. We also found that the above performances can be obtained with very small amount of dose (diodes are used as detectors. This makes the method suitable for in vivo range verification prior to each treatment delivery.

  17. Proton Beam Therapy for Unresectable Malignancies of the Nasal Cavity and Paranasal Sinuses

    Energy Technology Data Exchange (ETDEWEB)

    Zenda, Sadamoto, E-mail: szenda@east.ncc.go.jp [Division of Radiation Oncology, National Cancer Center Hospital East, Chiba (Japan); Kohno, Ryosuke; Kawashima, Mitsuhiko; Arahira, Satoko; Nishio, Teiji [Division of Radiation Oncology, National Cancer Center Hospital East, Chiba (Japan); Tahara, Makoto [Division of Gastrointestinal Oncology and Endoscopy, National Cancer Center Hospital East, Chiba (Japan); Hayashi, Ryuichi [Division of Head and Neck Surgery, National Cancer Center Hospital East, Chiba (Japan); Kishimoto, Seiji [Department of Head and Neck Surgery, Tokyo Medical and Dental University, Tokyo (Japan); Ogino, Takashi [Division of Radiation Oncology, National Cancer Center Hospital East, Chiba (Japan)

    2011-12-01

    Purpose: The cure rate for unresectable malignancies of the nasal cavity and paranasal sinuses is low. Because irradiation with proton beams, which are characterized by their rapid fall-off at the distal end of the Bragg peak and sharp lateral penumbra, depending on energy, depth, and delivery, provide better dose distribution than X-ray irradiation, proton beam therapy (PBT) might improve treatment outcomes for conditions located in proximity to risk organs. We retrospectively analyzed the clinical profile of PBT for unresectable malignancies of the nasal cavity and paranasal sinuses. Methods and Materials: We reviewed 39 patients in our database fulfilling the following criteria: unresectable malignant tumors of the nasal cavity, paranasal sinuses or skull base; N0M0 disease; and treatment with PBT (>60 GyE) from January 1999 to December 2006. Results: Median patient age was 57 years (range, 22-84 years); 22 of the patients were men and 17 were women. The most frequent primary site was the nasal cavity (n = 26, 67%). The local control rates at 6 months and 1 year were 84.6% and 77.0%, respectively. With a median active follow-up of 45.4 months, 3-year progression-free and overall survival were 49.1% and 59.3%, respectively. The most common acute toxicities were mild dermatitis (Grade 2, 33.3%), but no severe toxicity was observed (Grade 3 or greater, 0%). Five patients (12.8%) experienced Grade 3 to 5 late toxicities, and one treatment-related death was reported, caused by cerebrospinal fluid leakage Grade 5 (2.6%). Conclusion: These findings suggest that the clinical profile of PBT for unresectable malignancies of the nasal cavity and paranasal sinuses make it is a promising treatment option.

  18. Proton therapy with concomitant capecitabine for pancreatic and ampullary cancers is associated with a low incidence of gastrointestinal toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, R. Charles Jr.; Huh, Soon; Ho, Meng Wei; Mendenhall, Nancy P.; Morris, Christopher G.; Hoppe, Bradford S. [Univ. of Florida Proton Therapy Inst., Jacksonville (United States)], e-mail: rnichols@floridaproton.org; George, Thomas J.; Zaiden, Robert A. Jr. [Dept. of Hematology and Medical Oncology, Univ. of Florida, Gainesville and Jacksonville (United States); Awad, Ziad T. [Dept. of Surgery, Univ. of Florida, Jacksonville (United States); Asbun, Horacio J. [Dept. of Surgery, Mayo Clinic, Jacksonville (United States)

    2013-04-15

    Background: To review treatment toxicity for patients with pancreatic and ampullary cancer treated with proton therapy at our institution. Material and methods: From March 2009 through April 2012, 22 patients were treated with proton therapy and concomitant capecitabine (1000 mg PO twice daily) for resected (n = 5); marginally resectable (n = 5); and unresectable/inoperable (n = 12) biopsy-proven pancreatic and ampullary adenocarcinoma. Two patients with unresectable disease were excluded from the analysis for reasons unrelated to treatment. Proton doses ranged from 50.40 cobalt gray equivalent (CGE) to 59.40 CGE. Results: Median follow-up for all patients was 11 (range 5-36) months. No patient demonstrated any grade 3 toxicity during treatment or during the follow-up period. Grade 2 gastrointestinal toxicities occurred in three patients, consisting of vomiting (n = 3); and diarrhea (n = 2). Median weight loss during treatment was 1.3 kg (1.75% of body weight). Chemotherapy was well-tolerated with a median 99% of the prescribed doses delivered. Percentage weight loss was reduced (p = 0.0390) and grade 2 gastrointestinal toxicity was eliminated (p = 0.0009) in patients treated with plans that avoided anterior and left lateral fields which were associated with reduced small bowel and gastric exposure. Discussion: Proton therapy may allow for significant sparing of the small bowel and stomach and is associated with a low rate of gastrointestinal toxicity. Although long-term follow-up will be needed to assess efficacy, we believe that the favorable toxicity profile associated with proton therapy may allow for radiotherapy dose escalation, chemotherapy intensification, and possibly increased acceptance of preoperative radiotherapy for patients with resectable or marginally resectable disease.

  19. A treatment planning study to assess the feasibility of laser-driven proton therapy using a compact gantry design

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Kerstin M., E-mail: kerstin.hofmann@lrz.tu-muenchen.de; Wilkens, Jan J. [Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Ismaninger Str. 22, 81675 München, Germany and Physik-Department, Technische Universität München, James-Franck-Str. 1, 85748 Garching (Germany); Masood, Umar [OncoRay National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, PF 41, 01307 Dresden (Germany); Pawelke, Joerg [OncoRay National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, PF 41, 01307 Dresden, Germany and Institute of Radiation Physics, Helmholtz-Zentrum Dresden - Rossendorf, Bautzner Landstrasse 400, 01328 Dresden (Germany)

    2015-09-15

    Purpose: Laser-driven proton acceleration is suggested as a cost- and space-efficient alternative for future radiation therapy centers, although the properties of these beams are fairly different compared to conventionally accelerated proton beams. The laser-driven proton beam is extremely pulsed containing a very high proton number within ultrashort bunches at low bunch repetition rates of few Hz and the energy spectrum of the protons per bunch is very broad. Moreover, these laser accelerated bunches are subject to shot-to-shot fluctuations. Therefore, the aim of this study was to investigate the feasibility of a compact gantry design for laser-driven proton therapy and to determine limitations to comply with. Methods: Based on a published gantry beam line design which can filter parabolic spectra from an exponentially decaying broad initial spectrum, a treatment planning study was performed on real patient data sets. All potential parabolic spectra were fed into a treatment planning system and numerous spot scanning proton plans were calculated. To investigate limitations in the fluence per bunch, the proton number of the initial spectrum and the beam width at patient entrance were varied. A scenario where only integer shots are delivered as well as an intensity modulation from shot to shot was studied. The resulting plans were evaluated depending on their dosimetric quality and in terms of required treatment time. In addition, the influence of random shot-to-shot fluctuations on the plan quality was analyzed. Results: The study showed that clinically relevant dose distributions can be produced with the system under investigation even with integer shots. For small target volumes receiving high doses per fraction, the initial proton number per bunch must remain between 1.4 × 10{sup 8} and 8.3 × 10{sup 9} to achieve acceptable delivery times as well as plan qualities. For larger target volumes and standard doses per fraction, the initial proton number is even

  20. A treatment planning study to assess the feasibility of laser-driven proton therapy using a compact gantry design.

    Science.gov (United States)

    Hofmann, Kerstin M; Masood, Umar; Pawelke, Joerg; Wilkens, Jan J

    2015-09-01

    Laser-driven proton acceleration is suggested as a cost- and space-efficient alternative for future radiation therapy centers, although the properties of these beams are fairly different compared to conventionally accelerated proton beams. The laser-driven proton beam is extremely pulsed containing a very high proton number within ultrashort bunches at low bunch repetition rates of few Hz and the energy spectrum of the protons per bunch is very broad. Moreover, these laser accelerated bunches are subject to shot-to-shot fluctuations. Therefore, the aim of this study was to investigate the feasibility of a compact gantry design for laser-driven proton therapy and to determine limitations to comply with. Based on a published gantry beam line design which can filter parabolic spectra from an exponentially decaying broad initial spectrum, a treatment planning study was performed on real patient data sets. All potential parabolic spectra were fed into a treatment planning system and numerous spot scanning proton plans were calculated. To investigate limitations in the fluence per bunch, the proton number of the initial spectrum and the beam width at patient entrance were varied. A scenario where only integer shots are delivered as well as an intensity modulation from shot to shot was studied. The resulting plans were evaluated depending on their dosimetric quality and in terms of required treatment time. In addition, the influence of random shot-to-shot fluctuations on the plan quality was analyzed. The study showed that clinically relevant dose distributions can be produced with the system under investigation even with integer shots. For small target volumes receiving high doses per fraction, the initial proton number per bunch must remain between 1.4 × 10(8) and 8.3 × 10(9) to achieve acceptable delivery times as well as plan qualities. For larger target volumes and standard doses per fraction, the initial proton number is even more restricted to stay between 1.4

  1. WE-G-BRE-07: Proton Therapy Enhanced by Tumor-Targeting Gold Nanoparticles: A Pilot in Vivo Experiment at The Proton Therapy Center at MD Anderson Cancer Center

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, T; Grant, J; Wolfe, A; Gillin, M; Krishnan, S [MD Anderson Cancer Ctr., Houston, TX (United States)

    2014-06-15

    Purpose: Assess tumor-growth delay and survival in a mouse model of prostate cancer treated with tumor-targeting gold nanoparticles (AuNPs) and proton therapy. Methods: We first examined the accumulation of targeting nanoparticles within prostate tumors by imaging AuNPs with ultrasound-guided photoacoustics at 24h after the intravenous administration of goserelin-conjugated AuNPs (gAuNP) in three mice. Nanoparticles were also imaged at the cellular level with TEM in PC3 cells incubated with gAuNP for 24h. Pegylated AuNPs (pAuNP) were also imaged in vivo and in vitro for comparison. PC3 cells were then implanted subcutaneously in nude mice; 51mice with 8–10mm tumors were included. AuNPs were injected intravenously at 0.2%w/w final gold concentration 24h before irradiation. A special jig was designed to facilitate tumor irradiation perpendicular to the proton beam. Proton energy was set to 180MeV, the radiation field was 18×18cm{sup 2}, and 9cm or 13.5cm thick solid-water compensators were used to position the tumors at either the beam entrance (BE) or the SOBP. Physical doses of 5Gy were delivered to all tumors on a patient beam line at MD Anderson's Proton Therapy Center. Results: The photoacoustic experiment reveled that our nanoparticles leak from the tumor-feeding vasculature and accumulate within the tumor volume over time. Additionally, TEM images showed gAuNP are internalized in cancer cells, accumulating within the cytoplasm, whereas pAuNP are not. Tumor-growth was delayed by 11 or 32days in mice receiving gAuNP irradiated at the BE or the SOBP, relative to proton radiation alone. Survival curves (ongoing experiment) reveal that gAuNPs improved survival by 36% or 74% for tumors irradiated at the BE or SOBP. Conclusion: These important, albeit preliminary, in vivo findings reveal nanoparticles to be potent sensitizers to proton therapy. Further, conjugation of AuNPs to tumor-specific antigens that promote enhanced cellular internalization improved

  2. Commissioning of the discrete spot scanning proton beam delivery system at University of Texas M.D. Anderson Cancer Center, Proton Therapy Center, Houston

    Energy Technology Data Exchange (ETDEWEB)

    Gillin, Michael T.; Sahoo, Narayan; Bues, Martin; Ciangaru, George; Sawakuchi, Gabriel; Poenisch, Falk; Arjomandy, Bijan; Martin, Craig; Titt, Uwe; Suzuki, Kazumichi; Smith, Alfred R.; Zhu, X. Ronald [Department of Radiation Physics, U.T. MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States)

    2010-01-15

    Purpose: To describe a summary of the clinical commissioning of the discrete spot scanning proton beam at the Proton Therapy Center, Houston (PTC-H). Methods: Discrete spot scanning system is composed of a delivery system (Hitachi ProBeat), an electronic medical record (Mosaiq V 1.5), and a treatment planning system (TPS) (Eclipse V 8.1). Discrete proton pencil beams (spots) are used to deposit dose spot by spot and layer by layer for the proton distal ranges spanning from 4.0 to 30.6 g/cm{sup 2} and over a maximum scan area at the isocenter of 30x30 cm{sup 2}. An arbitrarily chosen reference calibration condition has been selected to define the monitor units (MUs). Using radiochromic film and ion chambers, the authors have measured spot positions, the spot sizes in air, depth dose curves, and profiles for proton beams with various energies in water, and studied the linearity of the dose monitors. In addition to dosimetric measurements and TPS modeling, significant efforts were spent in testing information flow and recovery of the delivery system from treatment interruptions. Results: The main dose monitors have been adjusted such that a specific amount of charge is collected in the monitor chamber corresponding to a single MU, following the IAEA TRS 398 protocol under a specific reference condition. The dose monitor calibration method is based on the absolute dose per MU, which is equivalent to the absolute dose per particle, the approach used by other scanning beam institutions. The full width at half maximum for the spot size in air varies from approximately 1.2 cm for 221.8 MeV to 3.4 cm for 72.5 MeV. The measured versus requested 90% depth dose in water agrees to within 1 mm over ranges of 4.0-30.6 cm. The beam delivery interlocks perform as expected, guarantying the safe and accurate delivery of the planned dose. Conclusions: The dosimetric parameters of the discrete spot scanning proton beam have been measured as part of the clinical commissioning program

  3. Commissioning of the discrete spot scanning proton beam delivery system at the University of Texas M.D. Anderson Cancer Center, Proton Therapy Center, Houston.

    Science.gov (United States)

    Gillin, Michael T; Sahoo, Narayan; Bues, Martin; Ciangaru, George; Sawakuchi, Gabriel; Poenisch, Falk; Arjomandy, Bijan; Martin, Craig; Titt, Uwe; Suzuki, Kazumichi; Smith, Alfred R; Zhu, X Ronald

    2010-01-01

    To describe a summary of the clinical commissioning of the discrete spot scanning proton beam at the Proton Therapy Center, Houston (PTC-H). Discrete spot scanning system is composed of a delivery system (Hitachi ProBeat), an electronic medical record (Mosaiq V 1.5), and a treatment planning system (TPS) (Eclipse V 8.1). Discrete proton pencil beams (spots) are used to deposit dose spot by spot and layer by layer for the proton distal ranges spanning from 4.0 to 30.6 g/cm2 and over a maximum scan area at the isocenter of 30 x 30 cm2. An arbitrarily chosen reference calibration condition has been selected to define the monitor units (MUs). Using radiochromic film and ion chambers, the authors have measured spot positions, the spot sizes in air, depth dose curves, and profiles for proton beams with various energies in water, and studied the linearity of the dose monitors. In addition to dosimetric measurements and TPS modeling, significant efforts were spent in testing information flow and recovery of the delivery system from treatment interruptions. The main dose monitors have been adjusted such that a specific amount of charge is collected in the monitor chamber corresponding to a single MU, following the IAEA TRS 398 protocol under a specific reference condition. The dose monitor calibration method is based on the absolute dose per MU, which is equivalent to the absolute dose per particle, the approach used by other scanning beam institutions. The full width at half maximum for the spot size in air varies from approximately 1.2 cm for 221.8 MeV to 3.4 cm for 72.5 MeV. The measured versus requested 90% depth dose in water agrees to within 1 mm over ranges of 4.0-30.6 cm. The beam delivery interlocks perform as expected, guarantying the safe and accurate delivery of the planned dose. The dosimetric parameters of the discrete spot scanning proton beam have been measured as part of the clinical commissioning program, and the machine is found to function in a safe

  4. SU-F-BRD-11: A Virtual Simulator Designed for Collision Prevention in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jung, H [Sungkyunkwan University, SAIHST, Seoul (Korea, Republic of); Kum, O [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Park, H; Choi, D; Han, Y [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: In proton therapy, collisions between patient and nozzle potentially occur in attaining minimal air gap due to the large nozzle structure. Thus, we developed software predicting the collisions of the nozzle and patient by simulating treatments. Methods: 3D modeling of a gantry inner-floor, nozzle and robotic-couch was done by using the SolidWorks based on the manufacturer’s machine data. To obtain patient body information, a 3D-scanner was utilized to scan a patient right before CT scanning. From the acquired images, a 3D-image of the patient’s body contour was reconstructed. The accuracy of the image was confirmed against the CT image for a humanoid phantom. The machine components and the virtual patient were combined on the treatment-room coordinate system, resulting in a virtual simulator. The simulator simulated the motion of its components such as rotation and translation of gantry, nozzle and couch, in real scale. Collision, if any, was examined both in static mode and dynamic mode. The static mode checks only at fixed positions of the machine’s components while dynamic mode examines while one component is in motion. Collision was notified if any voxel of two components, for example a nozzle and a patient or couch, overlapped when calculating volume locations. The event and collision point are visualized and colliding volumes are reported. Results: All components were successfully assembled and the motions could be accurately controlled. The 3D-shape of a phantom agreed with CT images within a deviation of 2 mm. Collision situations can be simulated within minutes and the results are displayed and reported. Conclusion: The developed software will be useful in improving patient safety and clinical efficiency for proton therapy. This work was supported by the National Research Foundation of Korea funded by Ministry of Science, ICT & Future Planning (2012M3A9B6055201, 2013M2A2A7043507), and Samsung Medical Center grant (GFO1130081)

  5. Hypofractionated proton therapy for prostate cancer: Dose delivery uncertainty due to interfractional motion

    Science.gov (United States)

    Wang, Yi; Efstathiou, Jason A.; Lu, Hsiao-Ming; Sharp, Gregory C.; Trofimov, Alexei

    2013-01-01

    Purpose: The α-to-β (α/β) ratio for prostate tumor is likely lower than that for the surrounding normal organs, such as rectum and bladder (∼3 Gy). As a result, hypofractionation is expected to improve the therapeutic ratio in prostate radiation therapy. However, with the use of fewer, larger fractions, the accuracy of treatment dose delivery becomes more influenced by the physical uncertainties resulting from motion and radiobiological uncertainties in the α/β ratio of the prostate tumor. The purpose of this study is to evaluate the impact of interfractional motion on treatment dose delivery within the likely range of the tumor α/β ratio. Methods: Serial CT images acquired at simulation and daily treatment for three prostate patients were studied retrospectively. A conventional 3D-conformal proton plan was created for each patient, delivering 25 fractions of 2 Gy to ITV1 (internal target volume, expanded from the prostate and clinically involved seminal vesicles) followed by 14 fractions to ITV2 (expanded from the prostate). The plans were renormalized for a series of hypofractionated protocols of between five and 28 fractions. The fractional doses were computed on daily CT and were mapped onto simulation CT using deformable registration. In each course, the doses from the fractions with the lowest D97% of the ITV2 were summed to approximate the lower limit (worst case) of target coverage. The uncertainty in dose and coverage was estimated as the deviation of the worst case from the nominal plan. Results: For treatments in 28 to five fractions, the uncertainty arising from interfractional motion ranged from ∼1% to 4% for V100% and ∼2% to 6% for D100% of the ITV2. The uncertainties in V95% and D95% were both minimal ( 2.5 Gy, assuming the worst case for interfractional motion. Conclusions: In hypofractionated proton therapy for prostate cancer, the dosimetric uncertainties due to interfractional motion were minimal for the ITV2 coverage at 95% isodose

  6. The design and implementation of decision support tools of proton beam therapy treatment planning of brain cancer patients

    Science.gov (United States)

    Le, Anh; Documet, Jorge; Joseph, Anika; Schulte, Reinhard; Liu, Brent

    2008-03-01

    Last year, we presented methodology to perform knowledge-based medical imaging informatics research on specific clinical scenarios where brain tumor patients are treated with Proton Beam Therapy (PT). In this presentation, we demonstrate the design and implementation of quantification and visualization tools to develop the knowledge base for therapy treatment planning based on DICOM-RT-ION objects. Proton Beam Therapy (PT) is a particular treatment that utilizes energized charged particles, protons, to deliver dose to the target region. Similar to traditional Radiation Therapy (RT), complex clinical imaging and informatics data are generated during the treatment process that guide the planning and the success of the treatment. Therefore, an Electronic Patient Record (ePR) System has been developed to standardize and centralize clinical imaging and informatics data and properly distribute data throughout the treatment duration. To further improve treatment planning process, we developed a set of decision support tools to improve the QA process in treatment planning process. One such example is a tool to assist in the planning of stereotactic PT cases where CT and MR images need to be analyzed simultaneously during treatment plan assessment. These tools are add-on features for DICOM standard ePR system of brain cancer patients and improve the clinical efficiency of PT treatment planning. Additional outcome data collected for PT cases are included in the overall DICOM-RT-ION database design as knowledge to enhance outcomes analysis for future PT adopters.

  7. Predictive Risk of Radiation Induced Cerebral Necrosis in Pediatric Brain Cancer Patients after VMAT Versus Proton Therapy

    Directory of Open Access Journals (Sweden)

    Derek Freund

    2015-04-01

    Full Text Available Cancer of the brain and central nervous system (CNS is the second most common of all pediatric cancers. Treatment of many of these cancers includes radiation therapy of which radiation induced cerebral necrosis (RICN can be a severe and potentially devastating side effect. Risk factors for RICN include brain volume irradiated, the dose given per fraction and total dose. Thirteen pediatric patients were selected for this study to determine the difference in predicted risk of RICN when treating with volumetric modulated arc therapy (VMAT compared to passively scattered proton therapy (PSPT and intensity modulated proton therapy (IMPT. Plans were compared on the basis of dosimetric endpoints in the planned treatment volume (PTV and brain and a radiobiological endpoint of RICN calculated using the Lyman-Kutcher-Burman probit model. Uncertainty tests were performed to determine if the predicted risk of necrosis was sensitive to positional errors, proton range errors and selection of risk models. Both PSPT and IMPT plans resulted in a significant increase in the maximum dose to the brain, a significant reduction in the total brain volume irradiated to low doses, and a significant lower predicted risk of necrosis compared with the VMAT plans. The findings of this study were upheld by the uncertainty analysis.

  8. Predictive Risk of Radiation Induced Cerebral Necrosis in Pediatric Brain Cancer Patients after VMAT Versus Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Freund, Derek; Zhang, Rui, E-mail: rzhang@marybird.com [Department of Radiation Oncology, Mary Bird Perkins Cancer Center, 4950 Essen Ln., Baton Rouge, LA 70809 (United States); Department of Physics and Astronomy, Louisiana State University, Nicholson Hall, Tower Dr., Baton Rouge, LA 70810 (United States); Sanders, Mary [Department of Radiation Oncology, Mary Bird Perkins Cancer Center, 4950 Essen Ln., Baton Rouge, LA 70809 (United States); Newhauser, Wayne [Department of Radiation Oncology, Mary Bird Perkins Cancer Center, 4950 Essen Ln., Baton Rouge, LA 70809 (United States); Department of Physics and Astronomy, Louisiana State University, Nicholson Hall, Tower Dr., Baton Rouge, LA 70810 (United States)

    2015-04-13

    Cancer of the brain and central nervous system (CNS) is the second most common of all pediatric cancers. Treatment of many of these cancers includes radiation therapy of which radiation induced cerebral necrosis (RICN) can be a severe and potentially devastating side effect. Risk factors for RICN include brain volume irradiated, the dose given per fraction and total dose. Thirteen pediatric patients were selected for this study to determine the difference in predicted risk of RICN when treating with volumetric modulated arc therapy (VMAT) compared to passively scattered proton therapy (PSPT) and intensity modulated proton therapy (IMPT). Plans were compared on the basis of dosimetric endpoints in the planned treatment volume (PTV) and brain and a radiobiological endpoint of RICN calculated using the Lyman-Kutcher-Burman probit model. Uncertainty tests were performed to determine if the predicted risk of necrosis was sensitive to positional errors, proton range errors and selection of risk models. Both PSPT and IMPT plans resulted in a significant increase in the maximum dose to the brain, a significant reduction in the total brain volume irradiated to low doses, and a significant lower predicted risk of necrosis compared with the VMAT plans. The findings of this study were upheld by the uncertainty analysis.

  9. Prospective MRI-based imaging study to assess feasibility of proton therapy for post-prostatectomy radiation.

    Science.gov (United States)

    Swisher-McClure, Samuel; Yin, Lingshu; Rosen, Mark; Batra, Sonny; Berman, Abigail T; Both, Stefan; Vapiwala, Neha

    2016-07-01

    To optimize delivery of post-prostatectomy radiation (PPRT) with protons by examining dosimetric effects of variations in physician contouring, organ motion, and patient alignment during a course of PPRT. We enrolled 10 patients receiving PPRT in a prospective imaging study. All patients underwent combined computed tomography (CT)/magnetic resonance imaging (MRI) simulation with endorectal balloon (ERB) and received intensity modulated radiation therapy (IMRT) per institutional standards. Study patients underwent weekly MRI verification scans in the treatment position. Three radiation oncologists contoured clinical target volumes (CTV) on initial and verification scans using two consensus guidelines (RTOG and EORTC). We generated IMRT, double scattering (DS), and pencil beam scanning (PBS) proton plans and examined the dosimetric impact of contour variations, inter-fraction motion, and patient alignment techniques. Inter-observer variations in contouring reduced median CTV coverage (D100) by 0.9% for IMRT plans, 2.8% for DS proton plans, 3.4-4.9% for PBS Proton Plans. Inter-fraction changes in target volumes due to internal organ motion resulted in a median loss of target dose coverage (D98) of 0% with IMRT, 3.5% with DS, and 8.1-8.3% with PBS. Median bladder V65Gy increased during the treatment course with all techniques (6.0-7.5%). Changes in the median rectal V60Gy remained small regardless of the treatment technique (0.5-3.1% increase). Alignment to the ERB after cranio-caudal bony alignment reduced CTV displacement compared to bony alignment alone, and as a result CTV coverage (D98) changed <2% with IMRT, DS, and PBS. Proton-based treatments are more sensitive to changes in inter-fraction organ motion during PPRT compared to IMRT, and therefore motion management and patient alignment methods are critical. Patient alignment using bony anatomy as well as the ERB minimizes displacement of the CTV, and reduces variation in target dose coverage particularly for

  10. Dose comparison according to Smooth Thickness application of Range compensator during proton therapy for brain tumor patient

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tase Woan; Kim, Dae Woong; Kim, Jae Weon; Jeong, Kyeong Sik [Proton Therapy Center, National Cancer Center, Goyang (Korea, Republic of)

    2016-12-15

    Range Compensator used for proton therapy compensates the proton beam dose which delivers to the normal tissues according to the Target's Distal Margin dose. We are going to check the improvement of dose on the target part by comparing the dose of PTV and OAR according to applying in different method of Smooth Thickness of Range Compensator which is used in brain tumor therapy. For 10 brain tumor patients taking proton therapy in National Cancer Center, Apply Smooth Thickness applied in Range Compensator in order from one to five by using Compensator Editor of Eclipse Proton Planning System(Version 10.0, Varian, USA). The therapy plan algorithm used Proton Convolution Superposition(version 8.1.20 or 10.0.28), and we compared Dmax, Dmin, Homogeneity Index, Conformity Index and OAR dose around tumor by applying Smooth Thickness in phase. When Smooth Thickness was applied from one to five, the Dmax of PTV was decreased max 4.3%, minimum at 0.8 and average of 1.81%. Dmin increased max 1.8%, min 1.8% and average. Difference between max dose and minimum dose decreased at max 5.9% min 1.4% and average 2.6%. Homogeneity Index decreased average of 0.018 and Conformity Index didn't had a meaningful change. OAR dose decreased in Brain Stem at max 1.6%, min 0.1% and average 0.6% and in Optic Chiasm max 1.3%, min 0.3%, and average 0.5%. However, patient C and patient E had an increase each 0.3% and 0.6%. Additionally, in Rt. Optic Nerve, there was a decrease at max 1.5%, min 0.3%, and average 0.8%, however, patient B had 0.1% increase. In Lt. Optic Nerve, there was a decrease at max 1.8%, min 0.3%, and average 0.7%, however, patient H had 0.4 increase. As Smooth Thickness of Range Compensator which is used as the proton treatment for brain tumor patients is applied in stages, the resolution of Compensator increased and as a result the most optimized amount of proton beam dose can be delivered. This is considered to be able to irradiate the equal amount at PTV and

  11. Reducing the Cost of Proton Radiation Therapy: The Feasibility of a Streamlined Treatment Technique for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Newhauser, Wayne D., E-mail: newhauser@lsu.edu [Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Baton Rouge, LA 70803 (United States); Department of Physics, Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, LA 70809 (United States); Zhang, Rui [Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Baton Rouge, LA 70803 (United States); Department of Physics, Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, LA 70809 (United States); Departments of Radiation Physics and Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 (United States); The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030 (United States); Jones, Timothy G. [Departments of Radiation Physics and Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 (United States); The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030 (United States); Department of Physics, Abilene Christian University, ACU Box 27963, Abilene, TX 79699 (United States); Giebeler, Annelise; Taddei, Phillip J. [Departments of Radiation Physics and Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 (United States); The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030 (United States); Stewart, Robert D. [Department of Radiation Oncology, University of Washington School of Medicine, 1959 NE Pacific Street, Box 356043, Seattle, WA 98195 (United States); Lee, Andrew [Departments of Radiation Physics and Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 (United States); Vassiliev, Oleg [Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Baton Rouge, LA 70803 (United States); Department of Physics, Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, LA 70809 (United States)

    2015-04-24

    Proton radiation therapy is an effective modality for cancer treatments, but the cost of proton therapy is much higher compared to conventional radiotherapy and this presents a formidable barrier to most clinical practices that wish to offer proton therapy. Little attention in literature has been paid to the costs associated with collimators, range compensators and hypofractionation. The objective of this study was to evaluate the feasibility of cost-saving modifications to the present standard of care for proton treatments for prostate cancer. In particular, we quantified the dosimetric impact of a treatment technique in which custom fabricated collimators were replaced with a multileaf collimator (MLC) and the custom range compensators (RC) were eliminated. The dosimetric impacts of these modifications were assessed for 10 patients with a commercial treatment planning system (TPS) and confirmed with corresponding Monte Carlo simulations. We assessed the impact on lifetime risks of radiogenic second cancers using detailed dose reconstructions and predictive dose-risk models based on epidemiologic data. We also performed illustrative calculations, using an isoeffect model, to examine the potential for hypofractionation. Specifically, we bracketed plausible intervals of proton fraction size and total treatment dose that were equivalent to a conventional photon treatment of 79.2 Gy in 44 fractions. Our results revealed that eliminating the RC and using an MLC had negligible effect on predicted dose distributions and second cancer risks. Even modest hypofractionation strategies can yield substantial cost savings. Together, our results suggest that it is feasible to modify the standard of care to increase treatment efficiency, reduce treatment costs to patients and insurers, while preserving high treatment quality.

  12. Reducing the Cost of Proton Radiation Therapy: The Feasibility of a Streamlined Treatment Technique for Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Wayne D. Newhauser

    2015-04-01

    Full Text Available Proton radiation therapy is an effective modality for cancer treatments, but the cost of proton therapy is much higher compared to conventional radiotherapy and this presents a formidable barrier to most clinical practices that wish to offer proton therapy. Little attention in literature has been paid to the costs associated with collimators, range compensators and hypofractionation. The objective of this study was to evaluate the feasibility of cost-saving modifications to the present standard of care for proton treatments for prostate cancer. In particular, we quantified the dosimetric impact of a treatment technique in which custom fabricated collimators were replaced with a multileaf collimator (MLC and the custom range compensators (RC were eliminated. The dosimetric impacts of these modifications were assessed for 10 patients with a commercial treatment planning system (TPS and confirmed with corresponding Monte Carlo simulations. We assessed the impact on lifetime risks of radiogenic second cancers using detailed dose reconstructions and predictive dose-risk models based on epidemiologic data. We also performed illustrative calculations, using an isoeffect model, to examine the potential for hypofractionation. Specifically, we bracketed plausible intervals of proton fraction size and total treatment dose that were equivalent to a conventional photon treatment of 79.2 Gy in 44 fractions. Our results revealed that eliminating the RC and using an MLC had negligible effect on predicted dose distributions and second cancer risks. Even modest hypofractionation strategies can yield substantial cost savings. Together, our results suggest that it is feasible to modify the standard of care to increase treatment efficiency, reduce treatment costs to patients and insurers, while preserving high treatment quality.

  13. Spot scanning proton therapy plan assessment: design and development of a dose verification application for use in routine clinical practice

    Science.gov (United States)

    Augustine, Kurt E.; Walsh, Timothy J.; Beltran, Chris J.; Stoker, Joshua B.; Mundy, Daniel W.; Parry, Mark D.; Bues, Martin; Fatyga, Mirek

    2016-04-01

    The use of radiation therapy for the treatment of cancer has been carried out clinically since the late 1800's. Early on however, it was discovered that a radiation dose sufficient to destroy cancer cells can also cause severe injury to surrounding healthy tissue. Radiation oncologists continually strive to find the perfect balance between a dose high enough to destroy the cancer and one that avoids damage to healthy organs. Spot scanning or "pencil beam" proton radiotherapy offers another option to improve on this. Unlike traditional photon therapy, proton beams stop in the target tissue, thus better sparing all organs beyond the targeted tumor. In addition, the beams are far narrower and thus can be more precisely "painted" onto the tumor, avoiding exposure to surrounding healthy tissue. To safely treat patients with proton beam radiotherapy, dose verification should be carried out for each plan prior to treatment. Proton dose verification systems are not currently commercially available so the Department of Radiation Oncology at the Mayo Clinic developed its own, called DOSeCHECK, which offers two distinct dose simulation methods: GPU-based Monte Carlo and CPU-based analytical. The three major components of the system include the web-based user interface, the Linux-based dose verification simulation engines, and the supporting services and components. The architecture integrates multiple applications, libraries, platforms, programming languages, and communication protocols and was successfully deployed in time for Mayo Clinic's first proton beam therapy patient. Having a simple, efficient application for dose verification greatly reduces staff workload and provides additional quality assurance, ultimately improving patient safety.

  14. Comparison of second cancer risk due to out-of-field doses from 6-MV IMRT and proton therapy based on 6 pediatric patient treatment plans

    Science.gov (United States)

    Athar, Basit S.; Paganetti, Harald

    2010-01-01

    Background and Purpose This study compared 6-MV IMRT and proton therapy in terms of organ specific second cancer lifetime attributable risks (LARs) caused by scattered and secondary out-of-field radiation. Material and Methods Based on simulated organ doses, excess relative and excess absolute risk models were applied to assess organ-specific LARs. Two treatment sites (cranium and central spine) were considered involving 6 treatment volumes and 6 patient ages (9-month, 4-year, 8-year, 11-year, 14-year, and adult). Results The LARs for thyroid cancer from a 6 cm diameter field treating a brain lesion in a 4-year old patient were estimated to be 1.1% and 0.3% in passive proton therapy and IMRT, respectively. However, estimated LARs for bladder cancer, more than 25 cm from the field edge for the same patient and treatment field, were estimated to be 0.2% and 0.02% from IMRT and proton therapy, respectively. Risks for proton beam scanning was found to be an order of magnitude smaller compared to passive proton therapy. Conclusion In terms of out-of-field risks, IMRT offers advantage close to the primary field and an increasing advantage for passive proton therapy is noticed with increasing distance to the field. Scanning proton beam therapy shows the lowest risks. PMID:21159398

  15. Accounting for range uncertainties in the optimization of intensity modulated proton therapy.

    Science.gov (United States)

    Unkelbach, Jan; Chan, Timothy C Y; Bortfeld, Thomas

    2007-05-21

    Treatment plans optimized for intensity modulated proton therapy (IMPT) may be sensitive to range variations. The dose distribution may deteriorate substantially when the actual range of a pencil beam does not match the assumed range. We present two treatment planning concepts for IMPT which incorporate range uncertainties into the optimization. The first method is a probabilistic approach. The range of a pencil beam is assumed to be a random variable, which makes the delivered dose and the value of the objective function a random variable too. We then propose to optimize the expectation value of the objective function. The second approach is a robust formulation that applies methods developed in the field of robust linear programming. This approach optimizes the worst case dose distribution that may occur, assuming that the ranges of the pencil beams may vary within some interval. Both methods yield treatment plans that are considerably less sensitive to range variations compared to conventional treatment plans optimized without accounting for range uncertainties. In addition, both approaches--although conceptually different--yield very similar results on a qualitative level.

  16. Including robustness in multi-criteria optimization for intensity-modulated proton therapy

    CERN Document Server

    Chen, Wei; Trofimov, Alexei; Madden, Thomas; Kooy, Hanne; Bortfeld, Thomas; Craft, David

    2011-01-01

    We present a method to include robustness into a multi-criteria optimization (MCO) framework for intensity-modulated proton therapy (IMPT). The approach allows one to simultaneously explore the trade-off between different objectives as well as the trade-off between robustness and nominal plan quality. In MCO, a database of plans each emphasizing different treatment planning objectives, is pre-computed to approximate the Pareto surface. An IMPT treatment plan that strikes the best balance between the different objectives can be selected by navigating on the Pareto surface. In our approach, robustness is integrated into MCO by adding robustified objectives and constraints to the MCO problem. Uncertainties of the robust problem are modeled by pre-calculated dose-influence matrices for a nominal scenario and a number of pre-defined error scenarios. A robustified objective represents the worst objective function value that can be realized for any of the error scenarios. The optimization method is based on a linear...

  17. Dosimetry intercomparison of four proton therapy institutions in Germany employing spot scanning

    Energy Technology Data Exchange (ETDEWEB)

    Baeumer, Christian; Koska, Benjamin [Westdeutsches Protonentherapiezentrum, Essen (Germany); Ackermann, Benjamin; Latzel, Harald [Heidelberger Ionenstrahl-Therapiezentrum, Heidelberg (Germany); Heidelberg Institute for Radiation Oncology (Germany); Hillbrand, Martin; Kaiser, Franz-Joachim [Rinecker Proton Therapy Center, Muenchen (Germany); Luehr, Armin [German Cancer Consortium (DKTK), Heidelberg (Germany); Technische Univ. Dresden (Germany). OncoRay - National Center for Radiation Research in Oncology; German Cancer Research Center (DKFZ), Heidelberg (Germany); Menkel, Stefan [Technische Univ. Dresden (Germany). Dept. of Radiation Oncology; Timmermann, Beate [Westdeutsches Protonentherapiezentrum, Essen (Germany); German Cancer Consortium (DKTK), Heidelberg (Germany); Essen Univ. Hospital (Germany). West German Cancer Center (WTZ)

    2017-08-01

    To verify the consistency of dose and range measurement in an interinstitution comparison among proton therapy institutions in Germany which use the pencil-beam scanning technique. Following a peer-to-peer approach absorbed dose and range have been intercompared in several missions at two hosting centers with two or three visiting physics teams of participating institutions using their own dosimetry equipment. A meta-analysis has been performed integrating the results of the individual missions. Dose has been determined with ionization chambers according to the dosimetry protocol IAEA TRS-398. For determination of the depth of the distal 80% dose the teams used either a scanning water phantom, a variable water column or a multi-layer ionization chamber. The systematic deviation between measured doses of the participating institutions is less than 1%. Ranges differ systematically less than 0.4 mm. The match of measured dose and range is better than expected from the respective uncertainties. As all physics teams agree on the assessment of absorbed dose and range, an important prerequisite for a start of joint clinical studies is fulfilled.

  18. Requirements for a Compton camera for in vivo range verification of proton therapy

    Science.gov (United States)

    Rohling, H.; Priegnitz, M.; Schoene, S.; Schumann, A.; Enghardt, W.; Hueso-González, F.; Pausch, G.; Fiedler, F.

    2017-04-01

    To ensure the optimal outcome of proton therapy, in vivo range verification is highly desired. Prompt γ-ray imaging (PGI) is a possible approach for in vivo range monitoring. For PGI, dedicated detection systems, e.g. Compton cameras, are currently under investigation. The presented paper deals with substantial requirements regarding hardware and software that a Compton camera used in clinical routine has to meet. By means of GEANT4 simulations, we investigate the load on the detectors and the percentage of background expected in a realistic irradiation and we simulate γ-ray detections subsequently used as input data for the reconstruction. By reconstructing events from simulated sources of well-defined geometry, we show that large-area detectors are favourable. We investigate reconstruction results in dependence of the number of events. Finally, an end-to-end test for a realistic patient scenario is presented: starting with a treatment plan, the γ-ray emissions are calculated, the detector response is modelled, and the image reconstruction is performed. By this, the complexity of the system is shown, and requirements and limitations regarding precision and costs are determined.

  19. A superconducting magnet mandrel with minimum symmetry laminations for proton therapy

    Science.gov (United States)

    Caspi, S.; Arbelaez, D.; Brouwer, L.; Dietderich, D. R.; Felice, H.; Hafalia, R.; Prestemon, S.; Robin, D.; Sun, C.; Wan, W.

    2013-08-01

    The size and weight of ion-beam cancer therapy gantries are frequently determined by a large aperture, curved, ninety degree, dipole magnet. The higher fields achievable with superconducting technology promise to greatly reduce the size and weight of this magnet and therefore also the gantry as a whole. This paper reports advances in the design of winding mandrels for curved, canted cosine-theta (CCT) magnets in the context of a preliminary magnet design for a proton gantry. The winding mandrel is integral to the CCT design and significantly affects the construction cost, stress management, winding feasibility, eddy current power losses, and field quality of the magnet. A laminated mandrel design using a minimum symmetry in the winding path is introduced and its feasibility demonstrated by a rapid prototype model. Piecewise construction of the mandrel using this laminated approach allows for increased manufacturing techniques and material choices. Sectioning the mandrel also reduces eddy currents produced during field changes accommodating the scan of beam energies during treatment. This symmetry concept can also greatly reduce the computational resources needed for 3D finite element calculations. It is shown that the small region of symmetry forming the laminations combined with periodic boundary conditions can model the entire magnet geometry disregarding the ends.

  20. SU-E-J-247: Time Evolution of Radiation-Induced Lung Injury After Stereotactic Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Grassberger, C; Sharp, G; Fintelmann, F; Paganetti, H; Willers, H [Massachusetts General Hospital, Boston, MA (United States)

    2015-06-15

    Purpose: Quantitative metrics to assess patient-specific radiation-induced lung injury have the potential to guide individualization of therapy and be early indicators of recurrence. Here we investigate computed tomography (CT) density changes in normal lung after stereotactic Proton Therapy. Methods: Participants in a phase-I clinical trial for stereotactic body radiation therapy (SBRT) with protons are analyzed on a rolling basis. The dataset includes 9 patients with 34 CT images to date. Follow-up images are registered to the planning CT using deformable image registration and the change in CT density is correlated to the dose to examine the time-evolution of Hounsfield Unit (HU) changes after large doses of proton radiation. Results: The lung density observed on the follow-up images increases significantly with dose for all dose levels above 5 Gy(RBE) (p<0.001) for 8/9 patients. The change per unit dose [HU/Gy] varies significantly among the patients, from 0.1 (for the one patient without significant correlation) to 5.7 ΔHU/Gy(RBE). The current population average of ΔHU/Gy(RBE) is 2.1, i.e. a 1 Gy(RBE) increase in dose leads on average to a 2.1 HU increase in CT density. The slope of the dose-response curve is constant for all timepoints investigated (from 3–24+ months). Additionally a pronounced non-linearity in the dose response curve is noted for long follow-up times (>18 months). Conclusion: CT density changes have a robust correlation with proton dose, quantitatively similar to photon dose, and may allow estimation of a patient’s intrinsic radiosensitivity after proton therapy. The stability of the correlation with time however diverges from what is known about CT response after photon irradiation. This could have important implications for clinical decision-making during proton therapy for lung cancer, especially for scheduling of follow-up CT/PET imaging and diagnosis of recurrence.

  1. Proton Neutron Gamma-X Detection (PNGXD): An introduction to contrast agent detection during proton therapy via prompt gamma neutron activation

    Science.gov (United States)

    Gräfe, James L.

    2017-09-01

    Proton therapy is an alternative external beam cancer treatment modality to the conventional linear accelerator-based X-ray radiotherapy. An inherent by-product of proton-nuclear interactions is the production of secondary neutrons. These neutrons have long been thought of as a secondary contaminant, nuisance, and source of secondary cancer risk. In this paper, a method is proposed to use these neutrons to identify and localize the presence of the tumor through neutron capture reactions with the gadolinium-based MRI contrast agent. This could provide better confidence in tumor targeting by acting as an additional quality assurance tool of tumor position during treatment. This effectively results in a neutron induced nuclear medicine scan. Gadolinium (Gd), is an ideal candidate for this novel nuclear contrast imaging procedure due to its unique nuclear properties and its widespread use as a contrast agent in MRI. Gd has one of the largest thermal neutron capture cross sections of all the stable nuclides, and the gadolinium-based contrast agents localize in leaky tissues and tumors. Initial characteristics of this novel concept were explored using the Monte Carlo code MCNP6. The number of neutron capture reactions per Gy of proton dose was found to be approximately 50,000 neutron captures/Gy, for a 8 cm3 tumor containing 300 ppm Gd at 8 cm depth with a simple simulation designed to represent the active delivery method. Using the passive method it is estimated that this number can be up to an order of magnitude higher. The thermal neutron distribution was found to not be localized within the spread out Bragg peak (SOBP) for this geometrical configuration and therefore would not allow for the identification of a geometric miss of the tumor by the proton SOBP. However, this potential method combined with nuclear medicine imaging and fused with online CBCT and prior MRI or CT imaging could help to identify tumor position during treatment. More computational and

  2. A new approach to integrate GPU-based Monte Carlo simulation into inverse treatment plan optimization for proton therapy

    Science.gov (United States)

    Li, Yongbao; Tian, Zhen; Song, Ting; Wu, Zhaoxia; Liu, Yaqiang; Jiang, Steve; Jia, Xun

    2017-01-01

    Monte Carlo (MC)-based spot dose calculation is highly desired for inverse treatment planning in proton therapy because of its accuracy. Recent studies on biological optimization have also indicated the use of MC methods to compute relevant quantities of interest, e.g. linear energy transfer. Although GPU-based MC engines have been developed to address inverse optimization problems, their efficiency still needs to be improved. Also, the use of a large number of GPUs in MC calculation is not favorable for clinical applications. The previously proposed adaptive particle sampling (APS) method can improve the efficiency of MC-based inverse optimization by using the computationally expensive MC simulation more effectively. This method is more efficient than the conventional approach that performs spot dose calculation and optimization in two sequential steps. In this paper, we propose a computational library to perform MC-based spot dose calculation on GPU with the APS scheme. The implemented APS method performs a non-uniform sampling of the particles from pencil beam spots during the optimization process, favoring those from the high intensity spots. The library also conducts two computationally intensive matrix-vector operations frequently used when solving an optimization problem. This library design allows a streamlined integration of the MC-based spot dose calculation into an existing proton therapy inverse planning process. We tested the developed library in a typical inverse optimization system with four patient cases. The library achieved the targeted functions by supporting inverse planning in various proton therapy schemes, e.g. single field uniform dose, 3D intensity modulated proton therapy, and distal edge tracking. The efficiency was 41.6  ±  15.3% higher than the use of a GPU-based MC package in a conventional calculation scheme. The total computation time ranged between 2 and 50 min on a single GPU card depending on the problem size.

  3. SU-E-J-122: Detecting Treatment-Induced Metabolic Abnormalities in Craniopharyngioma Patients Undergoing Surgery and Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hua, C; Shulkin, B; Li, Y; LI, X; Merchant, T [St. Jude Children' s Research Hospital, Memphis, TN (United States); Indelicato, D [University of Florida Proton Therapy Institute, Jacksonville, FL (United States); Boop, F [Semmes-Murphey Neurologic and Spine Institute, Memphis, TN (United States)

    2014-06-01

    Purpose: To identify treatment-induced defects in the brain of children with craniopharyngioma receiving surgery and proton therapy using fluorodeoxyglucose positron emission tomography (FDG PET). Methods: Forty seven patients were enrolled on a clinical trial for craniopharyngioma with serial imaging and functional evaluations. Proton therapy was delivered using the double-scattered beams with a prescribed dose of 54 Cobalt Gray Equivalent. FDG tracer uptake in each of 63 anatomical regions was computed after warping PET images to a 3D reference template in Talairach coordinates. Regional uptake was deemed significantly low or high if exceeding two standard deviations of normal population from the mean. For establishing the normal ranges, 132 children aged 1–20 years with noncentral nervous system related diseases and normal-appearing cerebral PET scans were analyzed. Age- and gender-dependent regional uptake models were developed by linear regression and confidence intervals were calculated. Results: Most common PET abnormality before proton therapy was significantly low uptake in the frontal lobe, the occipital lobe (particularly in cuneus), the medial and ventral temporal lobe, cingulate gyrus, caudate nuclei, and thalamus. They were related to injury from surgical corridors, tumor mass effect, insertion of a ventricular catheter, and the placement of an Ommaya reservoir. Surprisingly a significantly high uptake was observed in temporal gyri and the parietal lobe. In 13 patients who already completed 18-month PET scans, metabolic abnormalities improved in 11 patients from baseline. One patient had persistent abnormalities. Only one revealed new uptake abnormalities in thalamus, brainstem, cerebellum, and insula. Conclusion: Postoperative FDG PET of craniopharyngioma patients revealed metabolic abnormalities in specific regions of the brain. Proton therapy did not appear to exacerbate these surgery- and tumor-induced defects. In patients with persistent and

  4. Photon and proton therapy planning comparison for malignant glioma based on CT, FDG-PET, DTI-MRI and fiber tracking

    DEFF Research Database (Denmark)

    Munck af Rosenschöld, Per; Engelholm, Silke; Ohlhues, Lars;

    2011-01-01

    The purpose of this study was to compare treatment plans generated using fixed beam Intensity Modulated photon Radiation Therapy (IMRT), inversely optimized arc therapy (RapidArc(R), RA) with spot-scanned Intensity Modulated Proton Therapy (IMPT) for high-grade glioma patients. Plans were compared...

  5. Development and implementation of an anthropomorphic pediatric spine phantom for the assessment of craniospinal irradiation procedures in proton therapy

    Directory of Open Access Journals (Sweden)

    Dana J Lewis

    2014-03-01

    Full Text Available Purpose: To design an anthropomorphic pediatric spine phantom for use in the evaluation of proton therapy facilities for clinical trial participation by the Imaging and Radiation Oncology Core (IROC Houston QA Center (formerly RPC.Methods: This phantom was designed to perform an end-to-end audit of the proton spine treatment process, including simulation, dose calculation by the treatment planning system (TPS, and proton treatment delivery. The design incorporated materials simulating the thoracic spinal column of a pediatric patient, along with two thermoluminescent dosimeter (TLD-100 capsules and radiochromic film embedded in the phantom for dose evaluation. Fourteen potential materials were tested to determine relative proton stopping power (RSP and Hounsfield unit (HU values. Each material was CT scanned at 120 kVp, and the RSP was obtained from depth ionization scans using the Zebra multi-layer ion chamber (MLIC at two energies: 160 MeV and 250 MeV. To determine tissue equivalency, the measured RSP for each material was compared to the RSP calculated by the Eclipse TPS for a given HU.Results: The materials selected as bone, tissue, and cartilage substitutes were Techron HPV Bearing Grade (Boedeker Plastics, Inc., solid water, and blue water, respectively. The RSP values did not differ by more than 1.8% between the two energies. The measured RSP for each selected material agreed with the RSP calculated by the Eclipse TPS within 1.2%.Conclusion: An anthropomorphic pediatric proton spine phantom was designed to evaluate proton therapy delivery. The inclusion of multiple tissue substitutes increases heterogeneity and the level of difficulty for institutions to successfully treat the phantom. The following attributes will be evaluated: absolute dose agreement, distal range, field width, junction match and right/left dose profile alignment. The phantom will be tested at several institutions using a 5% dose agreement criterion, and a 5%/3mm gamma

  6. SU-F-BRD-06: Robust Dose Calculation in Intensity Modulated Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Brosch, R [ASU, Tempe, AZ (United States); Liu, W [Mayo Clinic Arizona, Phoenix, AZ (United States)

    2015-06-15

    Purpose: Commissioning data for intensity modulated proton therapy (IMPT) must be post-processed by fits to ad-hoc functions to derive the dose calculation kernel parameters in a treatment planning system (TPS). Whether from experimental measurement or Monte Carlo simulation, the limited and noisy nature of such data makes this task very challenging. We present a method to improve the modeling of the lateral dose distribution of clinical energy proton beams in water to commission an in-house IMPT dose calculation engine. Methods: A linear sum of three Gaussian distribution functions was fitted to the lateral dose data in logarithmic scale. Starting values of fitting solutions were determined from the Generalized Highland Approximation. We exhaustively optimized the combinations of data weights with upper bounds of the fitting solutions to minimize confidence intervals of the fitting solutions while maintaining the coefficient of determination (R{sup 2}). Results: Across all energies, average confidence bounds improved 72.88% [Max: 88.28%, Min: 55.05%] for small angle coulomb scattering, 114.25% [409.13%, 66.72%,] for nuclear scattering, and 68.66% [141.09%, 33.27%] for large angle coulomb scattering, while the coefficients of determination of the fits (R{sup 2}) remained comparable. On average R {sup 2} only changed 0.18% and were very close to 1 (approx. 0.999). Wilcoxon signed rank tests comparing unweighted/unbounded fits with weighted/bounded fits averaged 0.0146 (Max: 0.177, Min: 7.05×10−{sup 7}) for small angle Coulomb, 0.0903 (0.945, 7.05×10−{sup 7}) for nuclear, and 0.254 (0.871, 1.86×10−{sup 6}) for large angle Coulomb scattering. This allows rejection of the null hypothesis for small angle Coulomb scattering at the 0.015 level and nuclear interaction at the 0.1 level. Conclusion: Optimal weights assigned to IMPT lateral dose data minimized fitting to stochastic noise in the tail region. Optimizing the upper bounds of fitting parameters improved

  7. Current Diagnosis and Management of Suspected Reflux Symptoms Refractory to Proton Pump Inhibitor Therapy.

    Science.gov (United States)

    Richter, Joel E

    2014-09-01

    Suspected reflux symptoms that are refractory to proton pump inhibitors (PPIs) are rapidly becoming the most common presentation of gastroesophageal reflux disease (GERD) in patients seen in gastroenterology clinics. These patients are a heterogeneous group, differing in symptom frequency and severity, PPI dosing regimens, and responses to therapy (from partial to absent). Before testing, the physician needs to question the patient carefully about PPI compliance and the timing of drug intake in relation to meals. Switching PPIs or doubling the dose is the next step, but only 20% to 25% of the group refractory to PPIs will respond. The first diagnostic test should be upper gastrointestinal endoscopy. In more than 90% of cases, the results will be normal, but persistent esophagitis may suggest pill esophagitis, eosinophilic esophagitis, or rarer diseases, such as lichen planus, Zollinger-Ellison syndrome, or genotype variants of PPI metabolism. If the endoscopy results are normal, esophageal manometry and especially reflux testing should follow. Whether patients should be tested on or off PPI therapy is controversial. Most physicians prefer to test patients off PPIs to identify whether abnormal acid reflux is even present; if it is not, PPIs can be stopped and other diagnoses sought. Testing patients on PPI therapy allows nonacid reflux to be identified, but more than 50% of patients have a normal test result, leaving the clinician with a conundrum-whether to stop PPIs or continue them because the GERD is being treated adequately. Alternative diagnoses in patients with refractory GERD and normal reflux testing include achalasia, eosinophilic esophagitis, gastroparesis, rumination, and aerophagia. However, more than 50% will be given the diagnosis of functional heartburn, a visceral hypersensitivity syndrome. Treating patients with PPI-refractory GERD-like symptoms can be difficult and frustrating. Any of the following may help: a histamine-2 receptor antagonist at

  8. SU-E-J-213: Imaging and Treatment Isocenter Verification of a Gantry Mounted Proton Therapy System

    Energy Technology Data Exchange (ETDEWEB)

    Price, S; Goddu, S; Rankine, L; Klein, E [Washington University, St. Louis, MO (United States)

    2014-06-01

    Purpose: The Mevion proton therapy machine is the first to feature a gantry mounted sychro-cyclotron. In addition, the system utilizes a 6D motion couch and kV imaging for precise proton therapy. To quantify coincidence between these systems, isocentricity tests were performed based on kV imaging alignment using radiochromic film. Methods: The 100 ton gantry and 6D robotic couch can rotate 190° around isocenter to provide necessary beam angles for treatment. The kV sources and detector panels are deployed as needed to acquire orthogonal portals. Gantry and couch mechanical isocenter were tested using star-shots and radiochromic-film (RCF). Using kV imaging, the star-shot phantom was aligned to an embedded fiducial and the isocenter was marked on RCF with a pinprick. The couch and gantry stars were performed by irradiating films at every 45° and 30°, respectively. A proton beam with a range and modulation-width of 18 cm was used. A Winston-Lutz test was also performed at the same gantry and couch rotations using a custom jig holding RCF and a tungsten ball placed at isocenter. A 2 cm diameter circular aperture was used for the irradiation. Results: The couch star-shot indicated a minimum tangent circle of 0.6 mm, with a 0.9 mm offset from the manually marked isocenter. The gantry star-shot showed a 0.6 mm minimum tangent circle with a 0.5 mm offset from the pinprick. The Winston Lutz test performed for gantry rotation showed a maximum deviation from center of 0.5 mm. Conclusion: Based on star-shots and Winston-Lutz tests, the proton gantry and 6D couch isocentricity are within 1 mm. In this study, we have shown that the methods commonly utilized for Linac characterization can be applied to proton therapy. This revolutionary proton therapy system possesses excellent agreement between the mechanical and radiation isocenter, providing highly precise treatment.

  9. Initial study of 3D dose verification of multi-field proton therapy treatment along match line with polymer gel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Avery, S; Freeman, C; Shahnazi, K, E-mail: avery@uphs.upenn.ed [Department of Radiation Oncology, University of Pennsylvania Medical Center, Philadelphia (United States)

    2010-11-01

    This paper is intended as an initial study for quality assurance benefits from polymer gel detectors to proton therapy treatments. Several gel types were explored for stability from batch to batch. The depth dose distributions in the gels were examined with regard to dose dependences and compared to baseline measurements. The results indicate polymer gel detectors may be able to verify dose in three dimensions along match line for proton therapy treatments

  10. Proton pump inhibitor-amoxicillin-clarithromycin versus proton pump inhibitor-amoxicillin-metronidazole as first-line Helicobacter pylori eradication therapy.

    Science.gov (United States)

    Nishizawa, Toshihiro; Suzuki, Hidekazu; Suzuki, Masayuki; Takahashi, Masahiko; Hibi, Toshifumi

    2012-09-01

    The aim of this study was to compare the efficacy and tolerability of the first-line Helicobacter pylori (H. pylori) eradication regimen composed of proton pump inhibitor, clarithromycin, and amoxicillin, with those of a regimen composed of proton pump inhibitor, metronidazole, and amoxicillin. Data of patients, who were administered the first-line H. pylori eradication regimen at Tokyo Medical Center between 2008 and 2011, were reviewed. All patients had H. pylori gastritis without peptic ulcer disease. The 7-day triple regimen composed of lansoprazole, clarithromycin, and amoxicillin was administered to 55 patients, and that composed of omeprazole, metronidazole, and amoxicillin was administered to 55 patients. Intention-to-treat and per-protocol eradication rates were 74.5 and 80.4%, respectively, for the regimen of lansoprazole, clarithromycin, and amoxicillin, whereas the corresponding rates were 96.4 and 100%, respectively, for the regimen of omeprazole, metronidazole, and amoxicillin. In conclusion, first-line H. pylori eradication therapy composed of omeprazole, metronidazole, and amoxicillin was significantly more effective than that composed of lansoprazole, clarithromycin, and amoxicillin, without differences in tolerability.

  11. Outcomes and Acute Toxicities of Proton Therapy for Pediatric Atypical Teratoid/Rhabdoid Tumor of the Central Nervous System

    Energy Technology Data Exchange (ETDEWEB)

    McGovern, Susan L., E-mail: slmcgove@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Okcu, M. Fatih [Texas Children' s Hematology and Oncology Centers, Department of Pediatrics, Baylor College of Medicine, Houston, Texas (United States); Munsell, Mark F. [Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Kumbalasseriyil, Nancy; Grosshans, David R.; McAleer, Mary F. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chintagumpala, Murali [Texas Children' s Hematology and Oncology Centers, Department of Pediatrics, Baylor College of Medicine, Houston, Texas (United States); Khatua, Soumen [Department of Pediatrics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mahajan, Anita [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2014-12-01

    Purpose: Atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system is a rare cancer primarily affecting children younger than 5 years old. Because patients are young and receive intensive chemotherapy, there is concern regarding late radiation toxicity, particularly as survival rates improve. Therefore, there is interest in using proton therapy to treat these tumors. This study was undertaken to investigate outcomes and acute toxicities associated with proton therapy for AT/RT. Methods and Materials: The records of 31 patients with AT/RT treated with proton radiation from October 2008 to August 2013 were reviewed. Demographics, treatment characteristics, and outcomes were recorded and analyzed. Results: Median age at diagnosis was 19 months (range, 4-55 months), with a median age at radiation start of 24 months (range, 6-62 months). Seventeen patients received local radiation with a median dose of 50.4 GyRBE (range, 9-54 GyRBE). Fourteen patients received craniospinal radiation; half received 24 GyRBE or less, and half received 30.6 GyRBE or more. For patients receiving craniospinal radiation, the median tumor dose was 54 GyRBE (range, 43.2-55.8 GyRBE). Twenty-seven patients (87%) completed the planned radiation. With median follow-up of 24 months for all patients (range, 3-53 months), median progression-free survival was 20.8 months and median overall survival was 34.3 months. Five patients (16%) developed clinical findings and imaging changes in the brainstem 1 to 4 months after radiation, consistent with radiation reaction; all cases resolved with steroids or bevacizumab. Conclusions: This is the largest report of children with AT/RT treated with proton therapy. Preliminary survival outcomes in this young pediatric population are encouraging compared to historic results, but further study is warranted.

  12. Monte Carlo simulation of the neutron spectral fluence and dose equivalent for use in shielding a proton therapy vault

    Science.gov (United States)

    Zheng, Yuanshui; Newhauser, Wayne; Klein, Eric; Low, Daniel

    2009-11-01

    Neutron production is of principal concern when designing proton therapy vault shielding. Conventionally, neutron calculations are based on analytical methods, which do not accurately consider beam shaping components and nozzle shielding. The goal of this study was to calculate, using Monte Carlo modeling, the neutron spectral fluence and neutron dose equivalent generated by a realistic proton therapy nozzle and evaluate how these data could be used in shielding calculations. We modeled a contemporary passive scattering proton therapy nozzle in detail with the MCNPX simulation code. The neutron spectral fluence and dose equivalent at various locations in the treatment room were calculated and compared to those obtained from a thick iron target bombarded by parallel proton beams, the simplified geometry on which analytical methods are based. The neutron spectral fluence distributions were similar for both methods, with deeply penetrating high-energy neutrons (E > 10 MeV) being most prevalent along the beam central axis, and low-energy neutrons predominating the neutron spectral fluence in the lateral region. However, unlike the inverse square falloff used in conventional analytical methods, this study shows that the neutron dose equivalent per therapeutic dose in the treatment room decreased with distance approximately following a power law, with an exponent of about -1.63 in the lateral region and -1.73 in the downstream region. Based on the simulated data according to the detailed nozzle modeling, we developed an empirical equation to estimate the neutron dose equivalent at any location and distance in the treatment vault, e.g. for cases in which detailed Monte Carlo modeling is not feasible. We applied the simulated neutron spectral fluence and dose equivalent to a shielding calculation as an example.

  13. TH-C-BRD-09: Successes and Limitations of Online Range Adaptive Spot Scanning Proton Therapy for NSCLC

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, JP [UT MD Anderson Cancer Center, Houston, TX (United States); UT Graduate School of Biomedical Sciences at Houston, Houston, TX (United States); Dong, L [Scripps Proton Therapy Center, San Diego, CA (United States); Park, P [Emory University, Scottsdale, GA (United States); Zhu, XR; Kudchadker, RJ; Frank, SJ; Court, LE [UT MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-15

    Purpose: To determine the ability to adapt discrete spot-scanning proton therapy (SSPT) plans based on geometric changes of anatomy to minimize normal tissue dose and maintain target coverage. Methods: We developed and tested a range-correction algorithm to compensate for anatomy changes in SSPT with correction factors for target lateral size changes and energy scaling. This algorithm adjusts the energy of each spot from the original optimized treatment plan to match the new daily anatomy based on water equivalent path-length. To correct for the lateral target size changes, the peripheral spots were scaled based on phantom studies with variable target size. For energy change corrections, alternative cumulative scaling factor lookup tables were generated based on calculated central-axis and integral depth dose calculations for different energies. These various adaptive algorithms were performed on 7 lung cancer patients that were previously treated with proton therapy and who required at least one adaptive intervention. Single-field optimized SSPT plans were generated for these patients with clinical beam angles. Dose-volume histogram metrics were obtained for these patients for both the non-adaptive and the different adaptive plans applied to the last available weekly CT scan. Results: The doses to normal tissue were largely reduced for the spinal cord (Dmax), total lung (V20Gy), and contralateral lung (V20Gy) for all different methods of adaptive planning. With both corrections applied, the average changes for these metrics were −6.2Gy, −2.7%, and −4.9%, respectively. The same method generated unacceptably high target hot spots with average target V110% increase of 12.3%. Conclusion: Adaptive methods based on direct adjustments to proton range can reduce normal tissue doses under large anatomical changes but are insufficient in achieving clinically acceptable target doses and generate unacceptably sizeable hot spots. Adaptive planning methods for proton

  14. Monte Carlo simulation of the neutron spectral fluence and dose equivalent for use in shielding a proton therapy vault.

    Science.gov (United States)

    Zheng, Yuanshui; Newhauser, Wayne; Klein, Eric; Low, Daniel

    2009-11-21

    Neutron production is of principal concern when designing proton therapy vault shielding. Conventionally, neutron calculations are based on analytical methods, which do not accurately consider beam shaping components and nozzle shielding. The goal of this study was to calculate, using Monte Carlo modeling, the neutron spectral fluence and neutron dose equivalent generated by a realistic proton therapy nozzle and evaluate how these data could be used in shielding calculations. We modeled a contemporary passive scattering proton therapy nozzle in detail with the MCNPX simulation code. The neutron spectral fluence and dose equivalent at various locations in the treatment room were calculated and compared to those obtained from a thick iron target bombarded by parallel proton beams, the simplified geometry on which analytical methods are based. The neutron spectral fluence distributions were similar for both methods, with deeply penetrating high-energy neutrons (E > 10 MeV) being most prevalent along the beam central axis, and low-energy neutrons predominating the neutron spectral fluence in the lateral region. However, unlike the inverse square falloff used in conventional analytical methods, this study shows that the neutron dose equivalent per therapeutic dose in the treatment room decreased with distance approximately following a power law, with an exponent of about -1.63 in the lateral region and -1.73 in the downstream region. Based on the simulated data according to the detailed nozzle modeling, we developed an empirical equation to estimate the neutron dose equivalent at any location and distance in the treatment vault, e.g. for cases in which detailed Monte Carlo modeling is not feasible. We applied the simulated neutron spectral fluence and dose equivalent to a shielding calculation as an example.

  15. Towards Effective and Efficient Patient-Specific Quality Assurance for Spot Scanning Proton Therapy

    Directory of Open Access Journals (Sweden)

    X. Ronald. Zhu

    2015-04-01

    Full Text Available An intensity-modulated proton therapy (IMPT patient-specific quality assurance (PSQA program based on measurement alone can be very time consuming due to the highly modulated dose distributions of IMPT fields. Incorporating independent dose calculation and treatment log file analysis could reduce the time required for measurements. In this article, we summarize our effort to develop an efficient and effective PSQA program that consists of three components: measurements, independent dose calculation, and analysis of patient-specific treatment delivery log files. Measurements included two-dimensional (2D measurements using an ionization chamber array detector for each field delivered at the planned gantry angles with the electronic medical record (EMR system in the QA mode and the accelerator control system (ACS in the treatment mode, and additional measurements at depths for each field with the ACS in physics mode and without the EMR system. Dose distributions for each field in a water phantom were calculated independently using a recently developed in-house pencil beam algorithm and compared with those obtained using the treatment planning system (TPS. The treatment log file for each field was analyzed in terms of deviations in delivered spot positions from their planned positions using various statistical methods. Using this improved PSQA program, we were able to verify the integrity of the data transfer from the TPS to the EMR to the ACS, the dose calculation of the TPS, and the treatment delivery, including the dose delivered and spot positions. On the basis of this experience, we estimate that the in-room measurement time required for each complex IMPT case (e.g., a patient receiving bilateral IMPT for head and neck cancer is less than 1 h using the improved PSQA program. Our experience demonstrates that it is possible to develop an efficient and effective PSQA program for IMPT with the equipment and resources available in the clinic.

  16. Proton pump inhibitors for reflux therapy in infants: effectiveness determined by impedance pH monitoring.

    Science.gov (United States)

    Castellani, Christoph; Huber-Zeyringer, Andrea; Bachmaier, Gerhard; Saxena, Amulya K; Höllwarth, Michael E

    2014-04-01

    To evaluate the influence of proton pump inhibitors (PPI) in predominantly milk-fed infants with symptoms of GERD by 24-h pH-multichannel intraluminal impedance (24-h pH-MII). Ten infants (8 males and 2 females) with a mean gestational age of 39 weeks (28-40) were included. 24-h pH-MII was performed before prescription and during intake of PPI. Total acid exposure time, bolus exposure time (acidic/non-acidic/total) and the number of refluxes (acidic/non-acidic/total) were determined. Clinical symptoms were recorded and used to calculate the Reflux Symptom Index (RSI) and the Symptom Severity Index (SSI). There was a significant decrease in the number of acidic refluxes, total acid exposure and acidic bolus exposure time. However, this went along with a significant increase in non-acidic bolus exposure time. The total number of refluxes and the total bolus exposure time remained unchanged. Under PPI, a decrease of SSI and RSI for pain-related symptoms could be observed. For respiratory symptoms and vomiting however no significant changes could be demonstrated. Under PPI, an improvement of pain-related symptoms could be shown. The decrease of acid exposure went along with an increase of non-acidic refluxes resulting in almost constant total reflux numbers. This finding is interpreted as main reason for some persisting symptoms despite adequate PPI dosage. Concluding from our data PPI therapy should only be indicated in case of pain, but has no effect in case of vomiting or recurrent respiratory symptoms.

  17. SU-E-T-439: Fundamental Verification of Respiratory-Gated Spot Scanning Proton Beam Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hamano, H; Yamakawa, T [Graduate School of Health Sciences, Fujita Health University, Toyoake (Japan); Hayashi, N; Kato, H [School of Health Sciences, Fujita Health University, Tayoake (Japan); Yasui, K [Department of Proton Therapy Technology, Nagoya Proton Therapy Center, Nagoya (Japan)

    2015-06-15

    Purpose: The spot-scanning proton beam irradiation with respiratory gating technique provides quite well dose distribution and requires both dosimetric and geometric verification prior to clinical implementation. The purpose of this study is to evaluate the impact of gating irradiation as a fundamental verification. Methods: We evaluated field width, flatness, symmetry, and penumbra in the gated and non-gated proton beams. The respiration motion was distinguished into 3 patterns: 10, 20, and 30 mm. We compared these contents between the gated and non-gated beams. A 200 MeV proton beam from PROBEAT-III unit (Hitachi Co.Ltd) was used in this study. Respiratory gating irradiation was performed by Quasar phantom (MODUS medical devices) with a combination of dedicated respiratory gating system (ANZAI Medical Corporation). For radiochromic film dosimetry, the calibration curve was created with Gafchromic EBT3 film (Ashland) on FilmQA Pro 2014 (Ashland) as film analysis software. Results: The film was calibrated at the middle of spread out Bragg peak in passive proton beam. The field width, flatness and penumbra in non-gated proton irradiation with respiratory motion were larger than those of reference beam without respiratory motion: the maximum errors of the field width, flatness and penumbra in respiratory motion of 30 mm were 1.75% and 40.3% and 39.7%, respectively. The errors of flatness and penumbra in gating beam (motion: 30 mm, gating rate: 25%) were 0.0% and 2.91%, respectively. The results of symmetry in all proton beams with gating technique were within 0.6%. Conclusion: The field width, flatness, symmetry and penumbra were improved with the gating technique in proton beam. The spot scanning proton beam with gating technique is feasible for the motioned target.

  18. SU-D-BRC-06: Experimental and Monte Carlo Studies of Fluence Corrections for Graphite Calorimetry in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Lourenco, A [University College London, London (United Kingdom); National Physical Laboratory, Teddington (United Kingdom); Thomas, R [National Physical Laboratory, Teddington (United Kingdom); Bouchard, H [University of Montreal, Montreal (Canada); Kacperek, A [National Eye Proton therapy Centre, Clatterbridge Cancer Centre, Wirral (United Kingdom); Vondracek, V [Proton Therapy Center, Prague (Czech Republic); Royle, G [University College London, London (United Kingdom); Palmans, H [National Physical Laboratory, Teddington (United Kingdom); EBG MedAustron GmbH, Wiener Neustadt (Austria)

    2016-06-15

    Purpose: For photon and electron beams, the standard device used to measure absorbed dose is a calorimeter. Standards laboratories are currently working on the establishment of graphite calorimeters as a primary standard for proton beams. To provide a practical method for graphite calorimetry, it is necessary to convert dose to graphite to dose to water, requiring knowledge of the water-to-graphite stopping-power ratio and the fluence correction factor. This study aims to present a novel method to determine fluence corrections experimentally, and to apply this methodology to low- and high-energy proton beams. Methods: Measurements were performed in 60 MeV and 180 MeV proton beams. Experimental information was obtained from depth-dose ionization chamber measurements performed in a water phantom. This was repeated with different thicknesses of graphite plates in front of the water phantom. One distinct advantage of this method is that only ionization chamber perturbation factors for water are required. Fluence corrections were also obtained through Monte Carlo simulations for comparison with the experiments. Results: The experimental observations made in this study confirm the Monte Carlo results. Overall, fluence corrections between water and graphite increased with depth, with a maximum correction of 1% for the low-energy beam and 4% for the high-energy beam. The results also showed that a fraction of the secondary particles generated in proton therapy beams do not have enough energy to cross the ionization chamber wall; thus, their contribution is not accounted for in the measured fluence corrections. This effect shows up as a discrepancy in fluence corrections of 1% and has been confirmed by simulations of the experimental setup. Conclusion: Fluence corrections derived by experiment do not account for low-energy secondary particles that are stopped in the ion chamber wall. This work will contribute to a practical graphite calorimetry technique for determining

  19. SU-C-204-07: The Production of Short-Lived Positron Emitters in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Buitenhuis, H J T; Dendooven, P; Biegun, A K; Goethem, M-J van; Graaf, E R van der; Brandenburg, S [University of Groningen, Groningen (Netherlands); Diblen, F [University of Groningen, Groningen (Netherlands); Ghent University, Ghent (Belgium)

    2015-06-15

    Purpose: To investigate the production and effect of short-lived positron emitters when using PET for in-vivo range verification during a proton therapy irradiation. Methods: The integrated production of short-lived positron emitters in the stopping of 55 MeV protons was measured in water, carbon, phosphorus and calcium targets. The experimental production rates are used to calculate the production on PMMA and a representative set of 4 tissue materials. The number of decays integrated over an irradiation in these materials is calculated as function of the duration of the irradiation, considering irradiations with the same total number of protons. Results: The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: 12-N (T1/2 = 11 ms) on carbon (9.5% of the 11-C production), 29-P (T1/2 = 4.1 s) on phosphorus (20% of the 30-P production) and 38m-K (T1/2 = 0.92 s) on calcium (113% of the 38g-K production). No short-lived nuclides are produced on water. The most noticeable Result is that for an irradiation in (carbon-rich) adipose tissue, 12-N will dominate the PET image up to an irradiation duration of 70 s. On bone tissue, 15-O dominates over 12-N after 7–15 s (depending on the carbon-to-oxygen ratio). Conclusions: The presence of 12-N needs to be considered in PET imaging during proton beam irradiations as, depending on tissue composition and PET scanning protocol, it may noticeably deteriorate image quality due to the large positron range blurring. The results presented warrant investigations into the energy-dependent production of 12-N, 29-P and 38m-K and their effect on PET imaging during proton irradiations.

  20. Efficiency of analytical and sampling-based uncertainty propagation in intensity-modulated proton therapy

    Science.gov (United States)

    Wahl, N.; Hennig, P.; Wieser, H. P.; Bangert, M.

    2017-07-01

    The sensitivity of intensity-modulated proton therapy (IMPT) treatment plans to uncertainties can be quantified and mitigated with robust/min-max and stochastic/probabilistic treatment analysis and optimization techniques. Those methods usually rely on sparse random, importance, or worst-case sampling. Inevitably, this imposes a trade-off between computational speed and accuracy of the uncertainty propagation. Here, we investigate analytical probabilistic modeling (APM) as an alternative for uncertainty propagation and minimization in IMPT that does not rely on scenario sampling. APM propagates probability distributions over range and setup uncertainties via a Gaussian pencil-beam approximation into moments of the probability distributions over the resulting dose in closed form. It supports arbitrary correlation models and allows for efficient incorporation of fractionation effects regarding random and systematic errors. We evaluate the trade-off between run-time and accuracy of APM uncertainty computations on three patient datasets. Results are compared against reference computations facilitating importance and random sampling. Two approximation techniques to accelerate uncertainty propagation and minimization based on probabilistic treatment plan optimization are presented. Runtimes are measured on CPU and GPU platforms, dosimetric accuracy is quantified in comparison to a sampling-based benchmark (5000 random samples). APM accurately propagates range and setup uncertainties into dose uncertainties at competitive run-times (GPU ≤slant {5} min). The resulting standard deviation (expectation value) of dose show average global γ{3% / {3}~mm} pass rates between 94.2% and 99.9% (98.4% and 100.0%). All investigated importance sampling strategies provided less accuracy at higher run-times considering only a single fraction. Considering fractionation, APM uncertainty propagation and treatment plan optimization was proven to be possible at constant time complexity

  1. Temporal Lobe Toxicity Analysis After Proton Radiation Therapy for Skull Base Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Pehlivan, Berrin [Center for Proton Therapy, Paul Scherrer Institute, Villigen (Switzerland); Ares, Carmen, E-mail: carmen.ares@psi.ch [Center for Proton Therapy, Paul Scherrer Institute, Villigen (Switzerland); Lomax, Antony J.; Stadelmann, Otto; Goitein, Gudrun; Timmermann, Beate; Schneider, Ralf A.; Hug, Eugen B. [Center for Proton Therapy, Paul Scherrer Institute, Villigen (Switzerland)

    2012-08-01

    Purpose: Temporal lobe (TL) parenchyma toxicity constitutes one of the most frequent late adverse event in high-dose proton therapy (PT) for tumors of the skull base. We analyzed clinical events with dosimetric parameters in our patients treated for skull base tumors with spot-scanning PT. Methods and Materials: Between 1998 and 2005, a total of 62 patients received PT to a median dose of 71.7 Gy (relative biologic effectiveness [RBE]) (range, 63-74 Gy). The dose-volume histogram of each TL and the entire brain parenchyma (BP) were analyzed according to maximum, mean, and minimum dose as well as doses to 0.5, 1, 2, and 3 cc of brain volume (D{sub 0.5}, D{sub 1}, D{sub 2}, D{sub 3}) and correlated with clinical events. Generalized equivalent uniform dose (gEUD) values were calculated. Results: At a mean follow-up of 38 months (range, 14-92 months), 2 patients had developed symptomatic Grade 3 and 5 patients asymptomatic Grade 1 TL toxicity. Mean doses to a 2-cc volume of BP increased from 71 {+-} 5 Gy (RBE) for no toxicity to 74 {+-} 5 Gy (RBE) for Grade 1 and to 76 {+-} 2 Gy (RBE) for Grade 3 toxicity. TL events occurred in 6 of 7 patients (86%) at or above dose levels of {>=}64 Gy (RBE) D{sub 3}, {>=}68 Gy (RBE) D{sub 2}, {>=}72 Gy (RBE) D{sub 1}, and {>=}73 Gy (RBE) D{sub 0.5}, respectively (p = NS). No statistically significant dose/volume threshold was detected between patients experiencing no toxicity vs. Grade 1 or Grade 3. A strong trend for Grade 1 and 3 events was observed, when the gEUD was 60 Gy. Conclusions: A statistically significant normal tissue threshold dose for BP has not been successfully defined. However, our data suggest that tolerance of TL and BP to fractionated radiotherapy appears to be correlated with tissue volume included in high-dose regions. Additional follow-up time and patient accrual is likely needed to achieve clinical significance for these dose-volume parameters investigated. Our findings support the importance of establishing

  2. Spot Weight Adaptation for Moving Target in Spot Scanning Proton Therapy

    Directory of Open Access Journals (Sweden)

    Paul eMorel

    2015-05-01

    Full Text Available Purpose: This study describes a real-time spot weight adaptation method in spot-scanning proton therapy for moving target or moving patient, so that the resultant dose distribution closely matches the planned dose distribution. Materials and Methods: The method proposed in this study adapts the weight (MU of the delivering pencil beam to that of the target spot it will actually hit during patient/target motion. The target spot a certain delivering pencil beam may hit relies on patient monitoring and/or motion modeling using four-dimensional (4D CT. After the adapted delivery, the required total weight (MU for this target spot is then subtracted from the planned value. With continuous patient motion and continuous spot scanning, the planned doses to all target spots will eventually be all fulfilled. In a proof-of-principle test, a lung case was presented with realistic temporal and motion parameters; the resultant dose distribution using spot weight adaptation was compared to that without using this method. The impact of the real-time patient/target position tracking or prediction was also investigated.Results: For moderate motion (i.e., mean amplitude 0.5 cm, D95% to the planning target volume (PTV was only 81.5% of the prescription (RX dose; with spot weight adaptation PTV D95% achieves 97.7%RX. For large motion amplitude (i.e., 1.5 cm, without spot weight adaptation PTV D95% is only 42.9% of RX; with spot weight adaptation, PTV D95% achieves 97.7%RX. Larger errors in patient/target position tracking or prediction led to worse final target coverage; an error of 3mm or smaller in patient/target position tracking is preferred. Conclusion: The proposed spot weight adaptation method was able to deliver the planned dose distribution and maintain target coverage when patient motion was involved. The successful implementation of this method would rely on accurate monitoring or prediction of patient/target motion.

  3. Motion mitigation for lung cancer patients treated with active scanning proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Grassberger, Clemens, E-mail: Grassberger.Clemens@mgh.harvard.edu [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 and Center for Proton Radiotherapy, Paul Scherrer Institute, Villigen-PSI 5232 (Switzerland); Dowdell, Stephen; Sharp, Greg; Paganetti, Harald [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States)

    2015-05-15

    Purpose: Motion interplay can affect the tumor dose in scanned proton beam therapy. This study assesses the ability of rescanning and gating to mitigate interplay effects during lung treatments. Methods: The treatments of five lung cancer patients [48 Gy(RBE)/4fx] with varying tumor size (21.1–82.3 cm{sup 3}) and motion amplitude (2.9–30.6 mm) were simulated employing 4D Monte Carlo. The authors investigated two spot sizes (σ ∼ 12 and ∼3 mm), three rescanning techniques (layered, volumetric, breath-sampled volumetric) and respiratory gating with a 30% duty cycle. Results: For 4/5 patients, layered rescanning 6/2 times (for the small/large spot size) maintains equivalent uniform dose within the target >98% for a single fraction. Breath sampling the timing of rescanning is ∼2 times more effective than the same number of continuous rescans. Volumetric rescanning is sensitive to synchronization effects, which was observed in 3/5 patients, though not for layered rescanning. For the large spot size, rescanning compared favorably with gating in terms of time requirements, i.e., 2x-rescanning is on average a factor ∼2.6 faster than gating for this scenario. For the small spot size however, 6x-rescanning takes on average 65% longer compared to gating. Rescanning has no effect on normal lung V{sub 20} and mean lung dose (MLD), though it reduces the maximum lung dose by on average 6.9 ± 2.4/16.7 ± 12.2 Gy(RBE) for the large and small spot sizes, respectively. Gating leads to a similar reduction in maximum dose and additionally reduces V{sub 20} and MLD. Breath-sampled rescanning is most successful in reducing the maximum dose to the normal lung. Conclusions: Both rescanning (2–6 times, depending on the beam size) as well as gating was able to mitigate interplay effects in the target for 4/5 patients studied. Layered rescanning is superior to volumetric rescanning, as the latter suffers from synchronization effects in 3/5 patients studied. Gating minimizes the

  4. Review article: immediate-release proton-pump inhibitor therapy--potential advantages.

    Science.gov (United States)

    Howden, C W

    2005-12-01

    The absorption of most oral proton-pump inhibitors is delayed by the enteric coating required to protect the acid-labile proton-pump inhibitor from degradation in the stomach and, as a result, antisecretory effect is also delayed. This article provides an overview of the pharmacokinetics and pharmacodynamics of a new immediate-release omeprazole [(IR-OME) Zegerid power for oral suspension; Santarus Inc., San Diego, CA, USA] and its potential advantages over delayed-release proton-pump inhibitors. Immediate-release omeprazole has a higher mean peak plasma omeprazole concentration (C(max)) and a significantly shorter mean time to reach C(max) (t(max)) than delayed-release omeprazole. Immediate-release omeprazole 40 mg has a prolonged antisecretory effect with median intragastric pH above 4.0 for 18.6 h/day at steady-state, after 7 days of once daily dosing. The sodium bicarbonate in immediate-release omeprazole protects the uncoated omeprazole from degradation by gastric acid. The accelerated antisecretory action of immediate-release omeprazole compared with delayed-release omeprazole may be due to the activation of proton pumps by the rapid neutralization of intragastric acid by the sodium bicarbonate. The faster onset of action seen with immediate-release omeprazole is not achieved by using an antacid with a delayed-release proton-pump inhibitor, because administering antacids with conventional delayed-release proton-pump inhibitors does not significantly enhance absorption of the proton-pump inhibitor. In conclusion, immediate-release omeprazole is associated with rapid absorption of omeprazole and rapid onset of antisecretory effect, without compromising the duration of acid suppression.

  5. Evaluation of the systematic error in using 3D dose calculation in scanning beam proton therapy for lung cancer.

    Science.gov (United States)

    Li, Heng; Liu, Wei; Park, Peter; Matney, Jason; Liao, Zhongxing; Chang, Joe; Zhang, Xiaodong; Li, Yupeng; Zhu, Ronald X

    2014-09-08

    The objective of this study was to evaluate and understand the systematic error between the planned three-dimensional (3D) dose and the delivered dose to patient in scanning beam proton therapy for lung tumors. Single-field and multifield optimized scanning beam proton therapy plans were generated for ten patients with stage II-III lung cancer with a mix of tumor motion and size. 3D doses in CT datasets for different respiratory phases and the time-weighted average CT, as well as the four-dimensional (4D) doses were computed for both plans. The 3D and 4D dose differences for the targets and different organs at risk were compared using dose-volume histogram (DVH) and voxel-based techniques, and correlated with the extent of tumor motion. The gross tumor volume (GTV) dose was maintained in all 3D and 4D doses, using the internal GTV override technique. The DVH and voxel-based techniques are highly correlated. The mean dose error and the standard deviation of dose error for all target volumes were both less than 1.5% for all but one patient. However, the point dose difference between the 3D and 4D doses was up to 6% for the GTV and greater than 10% for the clinical and planning target volumes. Changes in the 4D and 3D doses were not correlated with tumor motion. The planning technique (single-field or multifield optimized) did not affect the observed systematic error. In conclusion, the dose error in 3D dose calculation varies from patient to patient and does not correlate with lung tumor motion. Therefore, patient-specific evaluation of the 4D dose is important for scanning beam proton therapy for lung tumors.

  6. Comparison of out-of-field photon doses in 6 MV IMRT and neutron doses in proton therapy for adult and pediatric patients

    Science.gov (United States)

    Athar, Basit S.; Bednarz, Bryan; Seco, Joao; Hancox, Cindy; Paganetti, Harald

    2010-05-01

    The purpose of this study was to assess lateral out-of-field doses in 6 MV IMRT (intensity modulated radiation therapy) and compare them with secondary neutron equivalent dose contributions in proton therapy. We simulated out-of-field photon doses to various organs as a function of distance, patient's age, gender and treatment volumes based on 3, 6, 9 cm field diameters in the head and neck and spine region. The out-of-field photon doses to organs near the field edge were found to be in the range of 2, 5 and 10 mSv Gy-1 for 3 cm, 6 cm and 9 cm diameter IMRT fields, respectively, within 5 cm of the field edge. Statistical uncertainties calculated in organ doses vary from 0.2% to 40% depending on the organ location and the organ volume. Next, a comparison was made with previously calculated neutron equivalent doses from proton therapy using identical field arrangements. For example, out-of-field doses for IMRT to lung and uterus (organs close to the 3 cm diameter spinal field) were computed to be 0.63 and 0.62 mSv Gy-1, respectively. These numbers are found to be a factor of 2 smaller than the corresponding out-of-field doses for proton therapy, which were estimated to be 1.6 and 1.7 mSv Gy-1 (RBE), respectively. However, as the distance to the field edge increases beyond approximately 25 cm the neutron equivalent dose from proton therapy was found to be a factor of 2-3 smaller than the out-of-field photon dose from IMRT. We have also analyzed the neutron equivalent doses from an ideal scanned proton therapy (assuming not significant amount of absorbers in the treatment head). Out-of-field doses were found to be an order of magnitude smaller compared to out-of-field doses in IMRT or passive scattered proton therapy. In conclusion, there seem to be three geometrical areas when comparing the out-of-target dose from IMRT and (passive scattered) proton treatments. Close to the target (in-field, not analyzed here) protons offer a distinct advantage due to the lower

  7. Spot Scanning Proton Therapy for Malignancies of the Base of Skull: Treatment Planning, Acute Toxicities, and Preliminary Clinical Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Grosshans, David R., E-mail: dgrossha@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhu, X. Ronald; Melancon, Adam [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Allen, Pamela K. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Poenisch, Falk; Palmer, Matthew [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); McAleer, Mary Frances; McGovern, Susan L. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gillin, Michael [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); DeMonte, Franco [Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chang, Eric L. [Department of Radiation Oncology, University of Southern California Keck School of Medicine, Los Angeles, California (United States); Brown, Paul D.; Mahajan, Anita [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2014-11-01

    Purpose: To describe treatment planning techniques and early clinical outcomes in patients treated with spot scanning proton therapy for chordoma or chondrosarcoma of the skull base. Methods and Materials: From June 2010 through August 2011, 15 patients were treated with spot scanning proton therapy for chordoma (n=10) or chondrosarcoma (n=5) at a single institution. Toxicity was prospectively evaluated and scored weekly and at all follow-up visits according to Common Terminology Criteria for Adverse Events, version 3.0. Treatment planning techniques and dosimetric data were recorded and compared with those of passive scattering plans created with clinically applicable dose constraints. Results: Ten patients were treated with single-field-optimized scanning beam plans and 5 with multifield-optimized intensity modulated proton therapy. All but 2 patients received a simultaneous integrated boost as well. The mean prescribed radiation doses were 69.8 Gy (relative biological effectiveness [RBE]; range, 68-70 Gy [RBE]) for chordoma and 68.4 Gy (RBE) (range, 66-70) for chondrosarcoma. In comparison with passive scattering plans, spot scanning plans demonstrated improved high-dose conformality and sparing of temporal lobes and brainstem. Clinically, the most common acute toxicities included fatigue (grade 2 for 2 patients, grade 1 for 8 patients) and nausea (grade 2 for 2 patients, grade 1 for 6 patients). No toxicities of grades 3 to 5 were recorded. At a median follow-up time of 27 months (range, 13-42 months), 1 patient had experienced local recurrence and a second developed distant metastatic disease. Two patients had magnetic resonance imaging-documented temporal lobe changes, and a third patient developed facial numbness. No other subacute or late effects were recorded. Conclusions: In comparison to passive scattering, treatment plans for spot scanning proton therapy displayed improved high-dose conformality. Clinically, the treatment was well tolerated, and

  8. Advanced treatment planning methods for efficient radiation therapy with laser accelerated proton and ion beams.

    Science.gov (United States)

    Schell, Stefan; Wilkens, Jan J

    2010-10-01

    Laser plasma acceleration can potentially replace large and expensive cyclotrons or synchrotrons for radiotherapy with protons and ions. On the way toward a clinical implementation, various challenges such as the maximum obtainable energy still remain to be solved. In any case, laser accelerated particles exhibit differences compared to particles from conventional accelerators. They typically have a wide energy spread and the beam is extremely pulsed (i.e., quantized) due to the pulsed nature of the employed lasers. The energy spread leads to depth dose curves that do not show a pristine Bragg peak but a wide high dose area, making precise radiotherapy impossible without an additional energy selection system. Problems with the beam quantization include the limited repetition rate and the number of accelerated particles per laser shot. This number might be too low, which requires a high repetition rate, or it might be too high, which requires an additional fluence selection system to reduce the number of particles. Trying to use laser accelerated particles in a conventional way such as spot scanning leads to long treatment times and a high amount of secondary radiation produced when blocking unwanted particles. The authors present methods of beam delivery and treatment planning that are specifically adapted to laser accelerated particles. In general, it is not necessary to fully utilize the energy selection system to create monoenergetic beams for the whole treatment plan. Instead, within wide parts of the target volume, beams with broader energy spectra can be used to simultaneously cover multiple axially adjacent spots of a conventional dose delivery grid as applied in intensity modulated particle therapy. If one laser shot produces too many particles, they can be distributed over a wider area with the help of a scattering foil and a multileaf collimator to cover multiple lateral spot positions at the same time. These methods are called axial and lateral

  9. Feasibility study of using statistical process control to customized quality assurance in proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Rah, Jeong-Eun; Oh, Do Hoon [Department of Radiation Oncology, Myongji Hospital, Goyang 412-270 (Korea, Republic of); Shin, Dongho; Kim, Tae Hyun [Proton Therapy Center, National Cancer Center, Goyang 410-769 (Korea, Republic of); Kim, Gwe-Ya, E-mail: gweyakim@gmail.com [Department of Radiation Medicine and Applied Sciences, University of California, San Diego, California 92093 (United States)

    2014-09-15

    Purpose: To evaluate and improve the reliability of proton quality assurance (QA) processes and, to provide an optimal customized tolerance level using the statistical process control (SPC) methodology. Methods: The authors investigated the consistency check of dose per monitor unit (D/MU) and range in proton beams to see whether it was within the tolerance level of the daily QA process. This study analyzed the difference between the measured and calculated ranges along the central axis to improve the patient-specific QA process in proton beams by using process capability indices. Results: The authors established a customized tolerance level of ±2% for D/MU and ±0.5 mm for beam range in the daily proton QA process. In the authors’ analysis of the process capability indices, the patient-specific range measurements were capable of a specification limit of ±2% in clinical plans. Conclusions: SPC methodology is a useful tool for customizing the optimal QA tolerance levels and improving the quality of proton machine maintenance, treatment delivery, and ultimately patient safety.

  10. A comprehensive dosimetric study of pancreatic cancer treatment using three-dimensional conformal radiation therapy (3DCRT), intensity-modulated radiation therapy (IMRT), volumetric-modulated radiation therapy (VMAT), and passive-scattering and modulated-scanning proton therapy (PT)

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Xuanfeng; Dionisi, Francesco; Tang, Shikui; Ingram, Mark; Hung, Chun-Yu; Prionas, Evangelos; Lichtenwalner, Phil; Butterwick, Ian; Zhai, Huifang; Yin, Lingshu; Lin, Haibo; Kassaee, Alireza; Avery, Stephen, E-mail: stephen.avery@uphs.upenn.edu

    2014-07-01

    With traditional photon therapy to treat large postoperative pancreatic target volume, it often leads to poor tolerance of the therapy delivered and may contribute to interrupted treatment course. This study was performed to evaluate the potential advantage of using passive-scattering (PS) and modulated-scanning (MS) proton therapy (PT) to reduce normal tissue exposure in postoperative pancreatic cancer treatment. A total of 11 patients with postoperative pancreatic cancer who had been previously treated with PS PT in University of Pennsylvania Roberts Proton Therapy Center from 2010 to 2013 were identified. The clinical target volume (CTV) includes the pancreatic tumor bed as well as the adjacent high-risk nodal areas. Internal (iCTV) was generated from 4-dimensional (4D) computed tomography (CT), taking into account target motion from breathing cycle. Three-field and 4-field 3D conformal radiation therapy (3DCRT), 5-field intensity-modulated radiation therapy, 2-arc volumetric-modulated radiation therapy, and 2-field PS and MS PT were created on the patients’ average CT. All the plans delivered 50.4 Gy to the planning target volume (PTV). Overall, 98% of PTV was covered by 95% of the prescription dose and 99% of iCTV received 98% prescription dose. The results show that all the proton plans offer significant lower doses to the left kidney (mean and V{sub 18} {sub Gy}), stomach (mean and V{sub 20} {sub Gy}), and cord (maximum dose) compared with all the photon plans, except 3-field 3DCRT in cord maximum dose. In addition, MS PT also provides lower doses to the right kidney (mean and V{sub 18} {sub Gy}), liver (mean dose), total bowel (V{sub 20} {sub Gy} and mean dose), and small bowel (V{sub 15} {sub Gy} absolute volume ratio) compared with all the photon plans and PS PT. The dosimetric advantage of PT points to the possibility of treating tumor bed and comprehensive nodal areas while providing a more tolerable treatment course that could be used for dose

  11. Preliminary assessment of LiF and alanine detectors for the dosimetry of proton therapy beams

    Energy Technology Data Exchange (ETDEWEB)

    Fattibene, P.; Calicchia, A.; De Angelis, C.; Onori, S. [Istituto Superiore di Sanita, Rome (Italy)]|[Istituto Nazionale di Fisica Nucleare, Rome (Italy). Sezione Sanita; d`Errico, F. [Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari]|[Istituto Nazionale di Fisica Nucleare, Pisa (Italy); Egger, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-12-31

    An experimental intercomparison between the proton response of LiF TLD-100 and alanine detectors is reported. The investigations were performed with LiF chips and alanine pellets in a 62 MeV proton beam at the Paul Scherrer Institut in Villigen (CH). Results were compared with reference dosimetry provided by Markus type parallel plate ionization chamber. The response of the detectors was studied, in a phantom, at different beam penetration depths in pristine and modulated beams. For both alanine and TL detectors, within the experimental uncertainty of the measurements, no significant energy dependence in the response was observed down to the Bragg peak region. The sensitivity of alanine and LiF detectors to protons was measured in the centre of modulated Bragg peak and no significant difference was found with respect to {sup 60}Co. Contrary to LiF, alanine also offers a remarkable tissue equivalence which favours its choice for in-phantom dosimetry. (author).

  12. Evaluation of a multistage CdZnTe Compton camera for prompt γ imaging for proton therapy

    Science.gov (United States)

    McCleskey, M.; Kaye, W.; Mackin, D. S.; Beddar, S.; He, Z.; Polf, J. C.

    2015-06-01

    A new detector system, Polaris J from H3D, has been evaluated for its potential application as a Compton camera (CC) imaging device for prompt γ rays (PGs) emitted during proton radiation therapy (RT) for the purpose of dose range verification. This detector system consists of four independent CdZnTe detector stages and a coincidence module, allowing the user to construct a Compton camera in different geometrical configurations and to accept both double and triple scatter events. Energy resolution for the 662 keV line from 137Cs was found to be 9.7 keV FWHM. The raw absolute efficiencies for double and triple scatter events were 2.2 ×10-5 and 5.8 ×10-7, respectively, for γs from a 60Co source. The position resolution for the reconstruction of a point source from the measured CC data was about 2 mm. Overall, due to the low efficiency of the Polaris J CC, the current system was deemed not viable for imaging PGs emitted during proton RT treatment delivery. However, using a validated Monte Carlo model of the CC, we found that by increasing the size of the detectors and placing them in a two stage configuration, the efficiency could be increased to a level to make PG imaging possible during proton RT.

  13. An anthropomorphic breathing phantom of the thorax for testing new motion mitigation techniques for pencil beam scanning proton therapy

    Science.gov (United States)

    Perrin, R. L.; Zakova, M.; Peroni, M.; Bernatowicz, K.; Bikis, C.; Knopf, A. K.; Safai, S.; Fernandez-Carmona, P.; Tscharner, N.; Weber, D. C.; Parkel, T. C.; Lomax, A. J.

    2017-03-01

    Motion-induced range changes and incorrectly placed dose spots strongly affect the quality of pencil-beam-scanned (PBS) proton therapy, especially in thoracic tumour sites, where density changes are large. Thus motion-mitigation techniques are necessary, which must be validated in a realistic patient-like geometry. We report on the development and characterisation of a dynamic, anthropomorphic, thorax phantom that can realistically mimic thoracic motions and anatomical features for verifications of proton and photon 4D treatments. The presented phantom is of an average thorax size, and consists of inflatable, deformable lungs surrounded by a skeleton and skin. A mobile ‘tumour’ is embedded in the lungs in which dosimetry devices (such as radiochromic films) can be inserted. Motion of the tumour and deformation of the thorax is controlled via a custom made pump system driving air into and out of the lungs. Comprehensive commissioning tests have been performed to evaluate the mechanical performance of the phantom, its visibility on CT and MR imaging and its feasibility for dosimetric validation of 4D proton treatments. The phantom performed well on both regular and irregular pre-programmed breathing curves, reaching peak-to-peak amplitudes in the tumour of  90% in the central planes of the target. The results of this study demonstrate that this anthropomorphic thorax phantom is suitable for imaging and dosimetric studies in a thoracic geometry closely-matched to lung cancer patients under realistic motion conditions.

  14. submitter Variable RBE in proton therapy: comparison of different model predictions and their influence on clinical-like scenarios

    CERN Document Server

    Giovannini, Giulia; Cabal, Gonzalo; Bauer, Julia; Tessonnier, Thomas; Frey, Kathrin; Debus, Jürgen; Mairani, Andrea; Parodi, Katia

    2016-01-01

    Background: In proton radiation therapy a constant relative biological effectiveness (RBE) of 1.1 is usually assumed. However, biological experiments have evidenced RBE dependencies on dose level, proton linear energy transfer (LET) and tissue type. This work compares the predictions of three of the main radio-biological models proposed in the literature by Carabe-Fernandez, Wedenberg, Scholz and coworkers. Methods: Using the chosen models, a spread-out Bragg peak (SOBP) as well as two exemplary clinical cases (single field and two fields) for cranial proton irradiation, all delivered with state-of-the-art pencil-beam scanning, have been analyzed in terms of absorbed dose, dose-averaged LET $(LET_D)$, RBE-weighted dose $(D_{RBE})$ and biological range shift distributions. Results: In the systematic comparison of RBE predictions by the three models we could show different levels of agreement depending on $(α/β) x$ and LET values. The SOBP study emphasizes the variation of LET D and RBE not only as a functi...

  15. Shielding analysis of proton therapy accelerators: a demonstration using Monte Carlo-generated source terms and attenuation lengths.

    Science.gov (United States)

    Lai, Bo-Lun; Sheu, Rong-Jiun; Lin, Uei-Tyng

    2015-05-01

    Monte Carlo simulations are generally considered the most accurate method for complex accelerator shielding analysis. Simplified models based on point-source line-of-sight approximation are often preferable in practice because they are intuitive and easy to use. A set of shielding data, including source terms and attenuation lengths for several common targets (iron, graphite, tissue, and copper) and shielding materials (concrete, iron, and lead) were generated by performing Monte Carlo simulations for 100-300 MeV protons. Possible applications and a proper use of the data set were demonstrated through a practical case study, in which shielding analysis on a typical proton treatment room was conducted. A thorough and consistent comparison between the predictions of our point-source line-of-sight model and those obtained by Monte Carlo simulations for a 360° dose distribution around the room perimeter showed that the data set can yield fairly accurate or conservative estimates for the transmitted doses, except for those near the maze exit. In addition, this study demonstrated that appropriate coupling between the generated source term and empirical formulae for radiation streaming can be used to predict a reasonable dose distribution along the maze. This case study proved the effectiveness and advantage of applying the data set to a quick shielding design and dose evaluation for proton therapy accelerators.

  16. Microdosimetric investigations in a proton therapy beam with sequentially etched Cr-39 track detectors

    Energy Technology Data Exchange (ETDEWEB)

    Luszik-Bhadra, M.; Wiegel, B. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); d`Errico, F. [Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari]|[Istituto Nazionale di Fisica Nucleare, Pisa (Italy); Lusini, L. [Pisa Univ. (Italy). Dipt. di Costruzioni Meccaniche e Nucleari

    1996-12-31

    The applicability of CR-39 nuclear track detectors to the field of microdosimetry was experimentally investigated through a series of tests with monoenergetic charged particle fields. A special etching technique (intermittent etching and cleaning etch steps) was devised and employed to determine LET values along individual tracks on irradiated detector plates. The range of measurable LET values was inferred from the analysis of the etched track diameters created by monoenergetic protons, alpha particles and fission fragments. Based on these calibrations, measurements of track densities and LET distributions were performed at different depths in a CR-39 stack irradiated with 62 MeV protons. (author).

  17. The influence of lateral beam profile modifications in scanned proton and carbon ion therapy: a Monte Carlo study

    CERN Document Server

    Parodi, K; Kraemer, M; Sommerer, F; Naumann, J; Mairani, A; Brons, S

    2010-01-01

    Scanned ion beam delivery promises superior flexibility and accuracy for highly conformal tumour therapy in comparison to the usage of passive beam shaping systems. The attainable precision demands correct overlapping of the pencil-like beams which build up the entire dose distribution in the treatment field. In particular, improper dose application due to deviations of the lateral beam profiles from the nominal planning conditions must be prevented via appropriate beam monitoring in the beamline, prior to the entrance in the patient. To assess the necessary tolerance thresholds of the beam monitoring system at the Heidelberg Ion Beam Therapy Center, Germany, this study has investigated several worst-case scenarios for a sensitive treatment plan, namely scanned proton and carbon ion delivery to a small target volume at a shallow depth. Deviations from the nominal lateral beam profiles were simulated, which may occur because of misaligned elements or changes of the beam optic in the beamline. Data have been an...

  18. WE-F-16A-03: 3D Printer Application in Proton Therapy: A Novel Method to Deliver Passive-Scattering Proton Beams with a Fixed Range and Modulation for SRS and SRT

    Energy Technology Data Exchange (ETDEWEB)

    Ding, X; Witztum, A; Liang, X; Reiche, M; Lin, H; Teo, B; Yin, L; Fiene, J; McDonough, J; Kassaee, A [University Pennsylvania, Philadelphia, PA (United States)

    2014-06-15

    Purpose: To present a novel technique to deliver passive-scattering proton beam with fixed range and modulation using a 3D printed patient-specific bolus for proton stereotactic radiosurgery and radiotherapy. Methods: A CIRS head phantom was used to simulate a patient with a small brain lesion. A custom bolus was created in the Eclipse Treatment Planning System (TPS) to compensate for the different water equivalent depths from the patient surface to the target from multiple beam directions. To simulate arc therapy, a plan was created on the initial CT using three passive-scattering proton beams with a fixed range and modulations irradiating from different angles. The DICOM-RT structure file of the bolus was exported from the TPS and converted to STL format for 3D printing. The phantom was rescanned with the printed custom bolus and head cup to verify the dose distribution comparing to the initial plan. EBT3 films were placed in the sagital plane of the target to verify the delivered dose distribution. The relative stopping power of the printing material(ABSplus-P430) was measured using the Zebra multi-plate ion chamber. Results: The relative stopping power of the 3D printing material, ABSplus-P430 was 1.05 which is almost water equivalent. The dose difference between verification CT and Initial CT is almost negligible. Film measurement also confirmed the accuracy for this new proton delivery technique. Conclusion: Our method using 3D printed range modifiers simplify the treatment delivery of multiple passive-scattering beams in treatment of small lesion in brain. This technique makes delivery of multiple beam more efficient and can be extended to allow arc therapy with proton beams. The ability to create and construct complex patient specific bolus structures provides a new dimension in creating optimized quality treatment plans not only for proton therapy but also for electron and photon therapy.

  19. SU-E-T-569: Neutron Shielding Calculation Using Analytical and Multi-Monte Carlo Method for Proton Therapy Facility

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S; Shin, E H; Kim, J; Ahn, S H; Chung, K; Kim, D-H; Han, Y; Choi, D H [Samsung Medical Center, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: To evaluate the shielding wall design to protect patients, staff and member of the general public for secondary neutron using a simply analytic solution, multi-Monte Carlo code MCNPX, ANISN and FLUKA. Methods: An analytical and multi-Monte Carlo method were calculated for proton facility (Sumitomo Heavy Industry Ltd.) at Samsung Medical Center in Korea. The NCRP-144 analytical evaluation methods, which produced conservative estimates on the dose equivalent values for the shielding, were used for analytical evaluations. Then, the radiation transport was simulated with the multi-Monte Carlo code. The neutron dose at evaluation point is got by the value using the production of the simulation value and the neutron dose coefficient introduced in ICRP-74. Results: The evaluation points of accelerator control room and control room entrance are mainly influenced by the point of the proton beam loss. So the neutron dose equivalent of accelerator control room for evaluation point is 0.651, 1.530, 0.912, 0.943 mSv/yr and the entrance of cyclotron room is 0.465, 0.790, 0.522, 0.453 mSv/yr with calculation by the method of NCRP-144 formalism, ANISN, FLUKA and MCNP, respectively. The most of Result of MCNPX and FLUKA using the complicated geometry showed smaller values than Result of ANISN. Conclusion: The neutron shielding for a proton therapy facility has been evaluated by the analytic model and multi-Monte Carlo methods. We confirmed that the setting of shielding was located in well accessible area to people when the proton facility is operated.

  20. Photon and proton therapy planning comparison for malignant glioma based on CT, FDG-PET, DTI-MRI and fiber tracking

    DEFF Research Database (Denmark)

    Munck af Rosenschöld, Per; Engelholm, Silke; Ohlhues, Lars;

    2011-01-01

    The purpose of this study was to compare treatment plans generated using fixed beam Intensity Modulated photon Radiation Therapy (IMRT), inversely optimized arc therapy (RapidArc(R), RA) with spot-scanned Intensity Modulated Proton Therapy (IMPT) for high-grade glioma patients. Plans were compared...... with respect to target coverage and sparing of organs at risk (OARs), with special attention to the possibility of hippocampus sparing....

  1. Experimental evaluation of a spatial resampling technique to improve the accuracy of pencil-beam dose calculation in proton therapy.

    Science.gov (United States)

    Egashira, Yusuke; Nishio, Teiji; Matsuura, Taeko; Kameoka, Satoru; Uesaka, Mitsuru

    2012-07-01

    In proton therapy, pencil-beam algorithms (PBAs) are the most widely used dose calculation methods. However, the PB calculations that employ one-dimensional density scaling neglect the effects of lateral density heterogeneity on the dose distributions, whereas some particles included in such pencil beams could overextend beyond the interface of the density heterogeneity. We have simplified a pencil-beam redefinition algorithm (PBRA), which was proposed for electron therapy, by a spatial resampling technique toward an application for proton therapy. The purpose of this study is to evaluate the calculation results of the spatial resampling technique in terms of lateral density heterogeneity by comparison with the dose distributions that were measured in heterogeneous slab phantoms. The pencil beams are characterized for multiple residual-range (i.e., proton energy) bins. To simplify the PBRA, the given pencil beams are resampled on one or two transport planes, in which smaller sub-beams that are parallel to each other are generated. We addressed the problem of lateral density heterogeneity comparing the calculation results to the dose distributions measured at different depths in heterogeneous slab phantoms using a two-dimensional detector. Two heterogeneity slab phantoms, namely, phantoms A and B, were designed for the measurements and calculations. In phantom A, the heterogeneity slab was placed close to the surface. On the other hand, in phantom B, it was placed close to the Bragg peak in the mono-energetic proton beam. In measurements, lateral dose profiles showed a dose reduction and increment in the vicinity ofx = 0 mm in both phantoms at depths z = 142 and 161 mm due to lateral particle disequilibrium. In phantom B, these dose reduction/increment effects were higher/lower, respectively, than those in phantom A. This is because a longer distance from the surface to the heterogeneous slab increases the strength of proton scattering. Sub-beams, which were

  2. Dosimetric rationale and early experience at UFPTI of thoracic proton therapy and chemotherapy in limited-stage small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Colaco, Rovel J.; Huh, Soon; Nichols, Romaine; Morris, Christopher G.; Flampouri, Stella; Li, Zuofeng; Hoppe, Bradford S. [Univ. of Florida Proton Therapy Inst., Jacksonville (United States)], e-mail: bhoppe@floridaproton.org; D' Agostino, Harry [Dept. of Thoracic Surgery, Univ. of Florida Coll. of Medicine, Gainesville (United States); Pham, Dat C. [Dept. of Hematology and Medical Oncology, Univ. of Florida Coll. of Medicine, Gainesville (United States); Bajwa, Abubakr A. [Dept. of Medicine, Univ. of Florida Coll. of Medicine, Gainesville (United States)

    2013-04-15

    Background: Concurrent chemoradiotherapy (CRT) is the standard of care in patients with limited-stage small cell lung cancer (SCLC). Treatment with conventional x-ray therapy (XRT) is associated with high toxicity rates, particularly acute grade 3+ esophagitis and pneumonitis. We present outcomes for the first known series of limited-stage SCLC patients treated with proton therapy and a dosimetric comparison of lung and esophageal doses with intensity-modulated radiation therapy (IMRT). Material and methods: Six patients were treated; five concurrently and one sequentially. Five patients received 60-66 CGE in 30-34 fractions once daily and one patient received 45 CGE in 30 fractions twice daily. All six patients received prophylactic cranial irradiation. Common Terminology Criteria for Adverse Events, v3.0, was used to grade toxicity. IMRT plans were also generated and compared with proton plans. Results: The median follow-up was 12.0 months. The one-year overall and progression-free survival rates were 83% and 66%, respectively. There were no cases of acute grade 3+ esophagitis or acute grade 2+ pneumonitis, and no other acute grade 3+ non-hematological toxicities were seen. One patient with a history of pulmonary fibrosis and atrial fibrillation developed worsening symptoms four months after treatment requiring oxygen. Three patients died; two of progressive disease and one after a fall. The latter patient was disease-free at 36 months after treatment. Another patient recurred and is alive, while two patients remain disease-free at 12 months of follow-up. Proton therapy proved superior to IMRT across all esophageal and lung dose volume points. Conclusion. In this small series of SCLC patients treated with proton therapy with radical intent, treatment was well tolerated with no cases of acute grade 3+ esophagitis or acute grade 2+ pneumonitis. Dosimetric comparison showed better sparing of lung and esophagus with proton therapy. Proton therapy merits further

  3. Five-Year Outcomes from 3 Prospective Trials of Image-Guided Proton Therapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Mendenhall, Nancy P., E-mail: menden@shands.ufl.edu [University of Florida Proton Therapy Institute, Jacksonville, Florida (United States); Hoppe, Bradford S.; Nichols, Romaine C.; Mendenhall, William M.; Morris, Christopher G.; Li, Zuofeng; Su, Zhong [University of Florida Proton Therapy Institute, Jacksonville, Florida (United States); Williams, Christopher R.; Costa, Joseph [Division of Urology, College of Medicine, University of Florida, Jacksonville, Florida (United States); Henderson, Randal H. [University of Florida Proton Therapy Institute, Jacksonville, Florida (United States)

    2014-03-01

    Purpose: To report 5-year clinical outcomes of 3 prospective trials of image-guided proton therapy for prostate cancer. Methods and Materials: A total of 211 prostate cancer patients (89 low-risk, 82 intermediate-risk, and 40 high-risk) were treated in institutional review board-approved trials of 78 cobalt gray equivalent (CGE) in 39 fractions for low-risk disease, 78 to 82 CGE for intermediate-risk disease, and 78 CGE with concomitant docetaxel therapy followed by androgen deprivation therapy for high-risk disease. Toxicities were graded according to Common Terminology Criteria for Adverse Events (CTCAE), version 3.0. Median follow-up was 5.2 years. Results: Five-year rates of biochemical and clinical freedom from disease progression were 99%, 99%, and 76% in low-, intermediate-, and high-risk patients, respectively. Actuarial 5-year rates of late CTCAE, version 3.0 (or version 4.0) grade 3 gastrointestinal and urologic toxicity were 1.0% (0.5%) and 5.4% (1.0%), respectively. Median pretreatment scores and International Prostate Symptom Scores at >4 years posttreatment were 8 and 7, 6 and 6, and 9 and 8, respectively, among the low-, intermediate-, and high-risk patients. There were no significant changes between median pretreatment summary scores and Expanded Prostate Cancer Index Composite scores at >4 years for bowel, urinary irritative and/or obstructive, and urinary continence. Conclusions: Five-year clinical outcomes with image-guided proton therapy included extremely high efficacy, minimal physician-assessed toxicity, and excellent patient-reported outcomes. Further follow-up and a larger patient experience are necessary to confirm these favorable outcomes.

  4. A Monte Carlo study of the relationship between the time structures of prompt gammas and the in-vivo radiation dose in proton therapy

    Science.gov (United States)

    Shin, Wook-Geun; Min, Chul Hee; Shin, Jae-Ik; Jeong, Jong Hwi; Lee, Se Byeong

    2015-07-01

    For in-vivo range verification in proton therapy, attempts have been made to measure the spatial distribution of the prompt gammas generated by the proton-induced interactions and to determine the proton dose distribution. However, the high energies of prompt gammas and background gammas are still problematic in measuring the distribution. In this study, we suggested a new method for determining the in-vivo range by utilizing the time structure of the prompt gammas formed during the rotation of a range modulation wheel (RMW) in passive scattering proton therapy. To validate the Monte Carlo code simulating the proton beam nozzle, we compared the axial percent depth doses (PDDs) with the measured PDDs for varying beam range from 4.73 to 24.01 cm. Also, we assessed the relationship between the proton dose rate and the time structure of the prompt gammas in a water phantom. The results of the PDD showed agreement within relative errors of 1.1% in the distal range and 2.9% in the modulation width. The average dose difference in the modulation was assessed as less than 1.3% by comparison with the measurements. The time structure of prompt gammas was well-matched, within 0.39 ms, with the proton dose rate, and this enabled an accurate prediction of the in-vivo range.

  5. Range shift and dose perturbation with high-density materials in proton beam therapy

    Energy Technology Data Exchange (ETDEWEB)

    Nichiporov, D., E-mail: nichipor@indiana.edu [Indiana University Integrated Science and Technology Hall, 2401 Milo B. Sampson La, Bloomington, IN 47408-1398 (United States); Moskvin, V. [Indiana University School of Medicine, 535 Barnhill Dr., RT 041, Indianapolis, IN 46202 (United States); Indiana University Health Proton Therapy Center, 2425 Milo B. Sampson La, Bloomington, IN 47408 (United States); Fanelli, L. [Indiana University Health Proton Therapy Center, 2425 Milo B. Sampson La, Bloomington, IN 47408 (United States); Das, I.J. [Indiana University School of Medicine, 535 Barnhill Dr., RT 041, Indianapolis, IN 46202 (United States); Indiana University Health Proton Therapy Center, 2425 Milo B. Sampson La, Bloomington, IN 47408 (United States)

    2011-11-15

    Radiotherapy with proton beams requires accurate knowledge of the proton range. When materials with high atomic numbers (Z) and densities (e.g. prostheses or implants) are present in the patient, they give rise to pronounced uncertainties in computed tomography data and to large errors in proton range and dose calculations. A modified analytical expression is proposed for the observed range shift in water in the presence of a high-density material of known thickness and density. The expression was verified experimentally in a clinical beam with various thicknesses and materials in a water phantom, at several beam ranges and at different depths. Measurements were also made behind the medium-to-water interface to evaluate dose perturbation using a thin window parallel plate ion chamber. Primary particle fluence variations due to the range shift were studied in a separate experiment. The measured range shift was in good agreement ({+-}0.3 mm) with the analytical expression for most of the materials studied. A small, but consistent dependence of range shift on the energy of impinging protons was found. Dose perturbation factor in water downstream of the material is less than +5% for thicknesses up to 8 g/cm{sup 2}. The proposed analytical expression can be used in clinical situations to determine the range shift in patient caused by an implanted material. Dose perturbation in the presence of an implant is due to the changes in primary particle fluence resulting from several physical processes.

  6. Short-lived positron emitters in beam-on PET imaging during proton therapy

    NARCIS (Netherlands)

    Dendooven, P.; Buitenhuis, H. J. T.; Diblen, F.; Heeres, P. N.; Biegun, A. K.; Fiedler, F.; van Goethem, M-J; van der Graaf, E. R.; Brandenburg, Sijtze

    2015-01-01

    The only method for in vivo dose delivery verification in proton beam radiotherapy in clinical use today is positron emission tomography (PET) of the positron emitters produced in the patient during irradiation. PET imaging while the beam is on (so called beam-on PET) is an attractive option, provid

  7. Pharmacoeconomic analysis of proton pump inhibitor therapy and interventions to control Helicobacter pylori infection

    NARCIS (Netherlands)

    Klok, Rogier Martijn

    2006-01-01

    In dit proefschrift worden de farmacoeconomische aspecten van problemen in het bovenste deel van het gastrointestinale tract besproken. De uitwisselbaarheid van proton pomp remmers (PPRs) wordt besproken net als switch patronen na het aflopen van het patent van omeprazol, de eerste PPR op de Nederla

  8. Pharmacoeconomic analysis of proton pump inhibitor therapy and interventions to control Helicobacter pylori infection

    NARCIS (Netherlands)

    Klok, Rogier Martijn

    2006-01-01

    In dit proefschrift worden de farmacoeconomische aspecten van problemen in het bovenste deel van het gastrointestinale tract besproken. De uitwisselbaarheid van proton pomp remmers (PPRs) wordt besproken net als switch patronen na het aflopen van het patent van omeprazol, de eerste PPR op de

  9. The Quest for Evidence for Proton Therapy : Model-Based Approach and Precision Medicine

    NARCIS (Netherlands)

    Widder, Joachim; van der Schaaf, Arjen; Lambin, Philippe; Marijnen, Corrie A. M.; Pignol, Jean-Philippe; Rasch, Coen R.; Slotman, Ben J.; Verheij, Marcel; Langendijk, Johannes A.

    2016-01-01

    Purpose: Reducing dose to normal tissues is the advantage of protons versus photons. We aimed to describe a method for translating this reduction into a clinically relevant benefit. Methods and Materials: Dutch scientific and health care governance bodies have recently issued landmark reports

  10. Proton Beam Therapy Versus Conformal Photon Radiation Therapy for Childhood Craniopharyngioma: Multi-institutional Analysis of Outcomes, Cyst Dynamics, and Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, Andrew J. [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States); Greenfield, Brad [Department of Radiation Oncology, Baylor College of Medicine, Houston, Texas (United States); Mahajan, Anita [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States); Paulino, Arnold C. [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, Baylor College of Medicine, Houston, Texas (United States); Okcu, M. Fatih [Department of Pediatrics, Texas Children' s Cancer and Hematology Center, Baylor College of Medicine, Houston, Texas (United States); Allen, Pamela K. [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States); Chintagumpala, Murali [Department of Pediatrics, Texas Children' s Cancer and Hematology Center, Baylor College of Medicine, Houston, Texas (United States); Kahalley, Lisa S. [Section of Psychology, Texas Children' s Cancer and Hematology Center, Baylor College of Medicine, Houston, Texas (United States); McAleer, Mary F.; McGovern, Susan L. [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States); Whitehead, William E. [Department of Neurosurgery, Texas Children' s Cancer and Hematology Center, Baylor College of Medicine, Houston, Texas (United States); Grosshans, David R., E-mail: dgrossha@mdanderson.org [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States)

    2014-10-01

    Purpose: We compared proton beam therapy (PBT) with intensity modulated radiation therapy (IMRT) for pediatric craniopharyngioma in terms of disease control, cyst dynamics, and toxicity. Methods and Materials: We reviewed records from 52 children treated with PBT (n=21) or IMRT (n=31) at 2 institutions from 1996-2012. Endpoints were overall survival (OS), disease control, cyst dynamics, and toxicity. Results: At 59.6 months' median follow-up (PBT 33 mo vs IMRT 106 mo; P<.001), the 3-year outcomes were 96% for OS, 95% for nodular failure-free survival and 76% for cystic failure-free survival. Neither OS nor disease control differed between treatment groups (OS P=.742; nodular failure-free survival P=.546; cystic failure-free survival P=.994). During therapy, 40% of patients had cyst growth (20% requiring intervention); immediately after therapy, 17 patients (33%) had cyst growth (transient in 14), more commonly in the IMRT group (42% vs 19% PBT; P=.082); and 27% experienced late cyst growth (32% IMRT, 19% PBT; P=.353), with intervention required in 40%. Toxicity did not differ between groups. On multivariate analysis, cyst growth was related to visual and hypothalamic toxicity (P=.009 and .04, respectively). Patients given radiation as salvage therapy (for recurrence) rather than adjuvant therapy had higher rates of visual and endocrine (P=.017 and .024, respectively) dysfunction. Conclusions: Survival and disease-control outcomes were equivalent for PBT and IMRT. Cyst growth is common, unpredictable, and should be followed during and after therapy, because it contributes to late toxicity. Delaying radiation therapy until recurrence may result in worse visual and endocrine function.

  11. SU-E-T-567: Neutron Dose Equivalent Evaluation for Pencil Beam Scanning Proton Therapy with Apertures

    Energy Technology Data Exchange (ETDEWEB)

    Geng, C [Massachusetts General Hospotal and Harvard Medical School, Boston, MA (United States); Nanjing University of Aeronautics and Astronautics, Nanjing (China); Schuemann, J; Moteabbed, M; Paganetti, H [Massachusetts General Hospotal and Harvard Medical School, Boston, MA (United States)

    2015-06-15

    Purpose: To determine the neutron contamination from the aperture in pencil beam scanning during proton therapy. Methods: A Monte Carlo based proton therapy research platform TOPAS and the UF-series hybrid pediatric phantoms were used to perform this study. First, pencil beam scanning (PBS) treatment pediatric plans with average spot size of 10 mm at iso-center were created and optimized for three patients with and without apertures. Then, the plans were imported into TOPAS. A scripting method was developed to automatically replace the patient CT with a whole body phantom positioned according to the original plan iso-center. The neutron dose equivalent was calculated using organ specific quality factors for two phantoms resembling a 4- and 14-years old patient. Results: The neutron dose equivalent generated by the apertures in PBS is 4–10% of the total neutron dose equivalent for organs near the target, while roughly 40% for organs far from the target. Compared to the neutron dose equivalent caused by PBS without aperture, the results show that the neutron dose equivalent with aperture is reduced in the organs near the target, and moderately increased for those organs located further from the target. This is due to the reduction of the proton dose around the edge of the CTV, which causes fewer neutrons generated in the patient. Conclusion: Clinically, for pediatric patients, one might consider adding an aperture to get a more conformal treatment plan if the spot size is too large. This work shows the somewhat surprising fact that adding an aperture for beam scanning for facilities with large spot sizes reduces instead of increases a potential neutron background in regions near target. Changran Geng is supported by the Chinese Scholarship Council (CSC) and the National Natural Science Foundation of China (Grant No. 11475087)

  12. Beam specific planning target volumes incorporating 4DCT for pencil beam scanning proton therapy of thoracic tumors

    CERN Document Server

    Lin, Liyong; Huang, Sheng; Mayer, Rulon; Thomas, Andrew; Solberg, Timothy D; McDonough, James E; Simone, Charles B

    2015-01-01

    The purpose of this study is to determine whether organ sparing and target coverage can be simultaneously maintained for pencil beam scanning (PBS) proton therapy treatment of thoracic tumors in the presence of motion, stopping power uncertainties and patient setup variations. Ten consecutive patients that were previously treated with proton therapy to 66.6/1.8 Gy (RBE) using double scattering (DS) were replanned with PBS. Minimum and maximum intensity images from 4DCT were used to introduce flexible smearing in the determination of the beam specific PTV (BSPTV). Datasets from eight 4DCT phases, using +-3% uncertainty in stopping power, and +-3 mm uncertainty in patient setup in each direction were used to create 8X12X10=960 PBS plans for the evaluation of ten patients. Plans were normalized to provide identical coverage between DS and PBS. The average lung V20, V5, and mean doses were reduced from 29.0%, 35.0%, and 16.4 Gy with DS to 24.6%, 30.6%, and 14.1 Gy with PBS, respectively. The average heart V30 and...

  13. Effectiveness and safety of proton beam therapy for advanced hepatocellular carcinoma with portal vein tumor thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Uk; Park, Joong-Won; Kim, Tae Hyun; Kim, Yeon-Joo; Woo, Sang Myung; Koh, Young-Hwan; Lee, Woo Jin; Park, Sang-Jae; Kim, Dae Yong; Kim, Chang-Min [National Cancer Center, Center for Liver Cancer, Research Institute and Hospital, Goyang-si, Gyeonggi-do (Korea, Republic of)

    2014-09-15

    To evaluate the clinical effectiveness and safety of proton beam therapy (PBT) in advanced hepatocellular carcinoma (HCC) patients with portal vein tumor thrombosis (PVTT). Twenty-seven HCC patients with PVTT underwent PBT, including 22 patients with modified International Union Against Cancer (mUICC) stage IVA,five patients with stage IVB primary tumors, and 16 with main PVTT. A median dose of 55 GyE (range, 50-66 GyE) in 20-22 fractions was delivered to a target volume encompassing both the PVTT and primary tumor. Overall, treatment was well tolerated, with no toxicity of grade ≥ 3. Median overall survival (OS) times in all patients and in stage IVA patients were 13.2 months and 16 months, respectively. Assessments of PVTT response showed complete response in 0 of 27 (0 %) patients, partial response in 15 (55.6 %), stable disease in 10 (37 %), and progressive disease in 2 (7.4 %) patients, with an objective response rate of 55.6 %. PVTT responders showed significantly higher actuarial 1-year local progression-free survival (LPFS; 85.6 % vs. 51.3 %), relapse-free survival (RFS; 20 % vs. 0 %) and OS (80 % vs. 25 %) rates than nonresponders (p < 0.05 each). Multivariate analysis showed that PVTT response and mUICC stage were independent prognostic factors for OS. Our data suggest that PBT could improve LPFS, RFS, and OS in advanced HCC patients with PVTT and it is feasible and safe for these patients. (orig.) [German] In der vorliegenden Arbeit wurde versucht, die klinische Wirksamkeit und Sicherheit der Protonenstrahltherapie (PBT) fuer Patienten mit fortgeschrittenem Leberzellkarzinom (HCC) in Verbindung mit Portadertumorthrombosen (PVTT) zu bewerten. Ausgefuehrt wurde die PBT fuer 27 HCC-Patienten mit PVTT, einschliesslich 22 Patienten im mUICC-Stadium (''International Union Against Cancer'') IVA sowie 5 Patienten mit Primaertumor im Stadium IVB und 16 Patienten mit PVTT im primaeren Stadium nach der geaenderten UICC-Klassifikation. Eine

  14. Factors influencing the accuracy of beam range estimation in proton therapy using prompt gamma emission

    Science.gov (United States)

    Janssen, FMFC; Landry, G.; Cambraia Lopes, P.; Dedes, G.; Smeets, J.; Schaart, D. R.; Parodi, K.; Verhaegen, F.

    2014-08-01

    In-vivo imaging is a strategy to monitor the range of protons inside the patient during radiation treatment. A possible method of in-vivo imaging is detection of secondary ‘prompt’ gamma (PG) photons outside the body, which are produced by inelastic proton-nuclear interactions inside the patient. In this paper, important parameters influencing the relationship between the PG profile and percentage depth dose (PDD) in a uniform cylindrical phantom are explored. Monte Carlo simulations are performed with the new Geant4 based code TOPAS for mono-energetic proton pencil beams (range: 100-250 MeV) and an idealized PG detector. PG depth profiles are evaluated using the inflection point on a sigmoid fit in the fall-off region of the profile. A strong correlation between the inflection point and the proton range determined from the PDD is found for all conditions. Variations between 1.5 mm and 2.7 mm in the distance between the proton range and the inflection point are found when either the mass density, phantom diameter, or detector acceptance angle is changed. A change in cut-off energy of the detector could induce a range difference of maximum 4 mm. Applying time-of-flight discrimination during detection, changing the primary energy of the beam or changing the elemental composition of the tissue affects the accuracy of the range prediction by less than 1 mm. The results indicate that the PG signal is rather robust to many parameter variations, but millimetre accurate range monitoring requires all medium and detector properties to be carefully taken into account.

  15. Comparison of organ-at-risk sparing and plan robustness for spot-scanning proton therapy and volumetric modulated arc photon therapy in head-and-neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Barten, Danique L. J., E-mail: d.barten@vumc.nl; Tol, Jim P.; Dahele, Max; Slotman, Ben J.; Verbakel, Wilko F. A. R. [Department of Radiotherapy, VU University Medical Center, De Boelelaan 1118, Amsterdam 1081 HV (Netherlands)

    2015-11-15

    Purpose: Proton radiotherapy for head-and-neck cancer (HNC) aims to improve organ-at-risk (OAR) sparing over photon radiotherapy. However, it may be less robust for setup and range uncertainties. The authors investigated OAR sparing and plan robustness for spot-scanning proton planning techniques and compared these with volumetric modulated arc therapy (VMAT) photon plans. Methods: Ten HNC patients were replanned using two arc VMAT (RapidArc) and spot-scanning proton techniques. OARs to be spared included the contra- and ipsilateral parotid and submandibular glands and individual swallowing muscles. Proton plans were made using Multifield Optimization (MFO, using three, five, and seven fields) and Single-field Optimization (SFO, using three fields). OAR sparing was evaluated using mean dose to composite salivary glands (Comp{sub Sal}) and composite swallowing muscles (Comp{sub Swal}). Plan robustness was determined for setup and range uncertainties (±3 mm for setup, ±3% HU) evaluating V95% and V107% for clinical target volumes. Results: Averaged over all patients Comp{sub Sal}/Comp{sub Swal} mean doses were lower for the three-field MFO plans (14.6/16.4 Gy) compared to the three-field SFO plans (20.0/23.7 Gy) and VMAT plans (23.0/25.3 Gy). Using more than three fields resulted in differences in OAR sparing of less than 1.5 Gy between plans. SFO plans were significantly more robust than MFO plans. VMAT plans were the most robust. Conclusions: MFO plans had improved OAR sparing but were less robust than SFO and VMAT plans, while SFO plans were more robust than MFO plans but resulted in less OAR sparing. Robustness of the MFO plans did not increase with more fields.

  16. Assessment of Early Toxicity and Response in Patients Treated With Proton and Carbon Ion Therapy at the Heidelberg Ion Therapy Center Using the Raster Scanning Technique

    Energy Technology Data Exchange (ETDEWEB)

    Rieken, Stefan; Habermehl, Daniel; Nikoghosyan, Anna; Jensen, Alexandra [Department of Radiation Oncology, University Hospital of Heidelberg, Heidelberg (Germany); Haberer, Thomas [Heidelberg Ion Therapy Center, Heidelberg (Germany); Jaekel, Oliver [Heidelberg Ion Therapy Center, Heidelberg (Germany); Department of Medical Physics, German Cancer Research Center (DKFZ), Heidelberg (Germany); Muenter, Marc W.; Welzel, Thomas; Debus, Juergen [Department of Radiation Oncology, University Hospital of Heidelberg, Heidelberg (Germany); Combs, Stephanie E., E-mail: Stephanie.Combs@med.uni-hedielberg.de [Department of Radiation Oncology, University Hospital of Heidelberg, Heidelberg (Germany)

    2011-12-01

    Puropose: To asses early toxicity and response in 118 patients treated with scanned ion beams to validate the safety of intensity-controlled raster scanning at the Heidelberg Ion Therapy Center. Patients and Methods: Between November 2009 and June 2010, we treated 118 patients with proton and carbon ion radiotherapy (RT) using active beam delivery. The main indications included skull base chordomas and chondrosarcomas, salivary gland tumors, and gliomas. We evaluated early toxicity within 6 weeks after RT and the initial clinical and radiologic response for quality assurance in our new facility. Results: In all 118 patients, few side effects were observed, in particular, no high numbers of severe acute toxicity were found. In general, the patients treated with particle therapy alone showed only a few single side effects, mainly Radiation Therapy Oncology Group/Common Terminology Criteria grade 1. The most frequent side effects and cumulative incidence of single side effects were observed in the head-and-neck patients treated with particle therapy as a boost and photon intensity-modulated RT. The toxicities included common radiation-attributed reactions known from photon RT, including mucositis, dysphagia, and skin erythema. The most predominant imaging responses were observed in patients with high-grade gliomas and those with salivary gland tumors. For skull base tumors, imaging showed a stable tumor outline in most patients. Thirteen patients showed improvement of pre-existing clinical symptoms. Conclusions: Side effects related to particle treatment were rare, and the overall tolerability of the treatment was shown. The initial response was promising. The data have confirmed the safe delivery of carbon ions and protons at the newly opened Heidelberg facility.

  17. Particle therapy for mucosal melanoma of the head and neck. A single-institution retrospective comparison of proton and carbon ion therapy

    Energy Technology Data Exchange (ETDEWEB)

    Demizu, Y.; Fujii, O.; Terashima, K.; Mima, M.; Hashimoto, N.; Fuwa, N. [Hyogo Ion Beam Medical Center, Department of Radiology, Tatsuno, Hyogo (Japan); Niwa, Y. [Hyogo College of Medicine, Department of Radiology, Nishinomiya, Hyogo (Japan); Akagi, T. [Hyogo Ion Beam Medical Center, Department of Radiation Physics, Tatsuno, Hyogo (Japan); Daimon, T. [Hyogo College of Medicine, Department of Biostatistics, Nishinomiya, Hyogo (Japan); Murakami, M. [Dokkyo Medical University, Center for Radiation Oncology, Shimotsuga-gun, Tochigi (Japan)

    2014-02-15

    To retrospectively analyze treatment outcomes after particle therapy using protons or carbon ions for mucosal melanoma of the head and neck (HNMM) at the Hyogo Ion Beam Medical Center, as well as to compare proton therapy (PT) and carbon ion therapy (CIT). Data from 62 HNMM patients without metastasis, treated with PT or CIT between October 2003 and April 2011 were analyzed. Median patient age was 70.5 years (range 33-89 years). Of the total patients, 33 (53 %) had received PT and 29 (47 %) had undergone CIT. Protocols for 65 or 70.2 GyE in 26 fractions were used for both ion types. Median follow-up was 18.0 months (range 5.2-82.7 months). The 1-/2-year overall survival (OS) and local control (LC) rates were 93 %/61 % and 93 %/78 % for all patients, 91 %/44 % and 92 %/71 % for the PT patients and 96 %/62 % and 95 %/59 % for the CIT patients, respectively. No significant differences were observed between PT and CIT. Local recurrence was observed in 8 patients (PT: 5, CIT: 3) and 29 (PT: 18, CIT: 11) experienced distant metastases. Acute reactions were acceptable and all patients completed the planned radiotherapy. Regarding late toxicity, grade 3 or greater events were observed in 5 patients (PT: 3, CIT: 2), but no significant difference was observed between PT and CIT. Our single-institution retrospective analysis demonstrated that particle therapy for HNMM achieved good LC, but OS was unsatisfactory. There were no significant differences between PT and CIT in terms of either efficacy or toxicity. (orig.)

  18. Dosimetric comparison study between intensity modulated radiation therapy and three-dimensional conformal proton therapy for pelvic bone marrow sparing in the treatment of cervical cancer.

    Science.gov (United States)

    Song, William Y; Huh, Soon N; Liang, Yun; White, Greg; Nichols, R Charles; Watkins, W Tyler; Mundt, Arno J; Mell, Loren K

    2010-08-15

    The objective was to compare intensity-modulated radiation therapy (IMRT) with 3D conformal proton therapy (3DCPT) in the treatment of cervical cancer. In particular, each technique's ability to spare pelvic bone marrow (PBM) was of primary interest in this study. A total of six cervical cancer patients (3 postoperative and 3 intact) were planned and analyzed. All plans had uniform 1.0 cm CTV-PTV margin and satisfied the 95% PTV with 100% isodose (prescription dose = 45 Gy) coverage. Dose-volume histograms (DVH) were analyzed for comparison. The overall PTV and PBM volumes were 1035.9 ± 192.2 cc and 1151.4 ± 198.3 cc, respectively. In terms of PTV dose conformity index (DCI) and dose homogeneity index (DHI), 3DCPT was slightly superior to IMRT with 1.00 ± 0.001, 1.01 ± 0.02, and 1.10 ± 0.02, 1.13 ± 0.01, respectively. In addition, 3DCPT demonstrated superiority in reducing lower doses (i.e., V30 or less) to PBM, small bowel and bladder. Particularly in PBM, average V10 and V20 reductions of 10.8% and 7.4% (p = 0.001 and 0.04), respectively, were observed. However, in the higher dose range, IMRT provided better sparing (> V30). For example, in small bowel and PBM, average reductions in V45 of 4.9% and 10.0% (p = 0.048 and 0.008), respectively, were observed. Due to its physical characteristics such as low entrance dose, spread-out Bragg peak and finite particle range of protons, 3DCPT illustrated superior target coverage uniformity and sparing of the lower doses in PBM and other organs. Further studies are, however, needed to fully exploit the benefits of protons for general use in cervical cancer.

  19. Estimate of the uncertainties in the relative risk of secondary malignant neoplasms following proton therapy and intensity-modulated photon therapy

    Science.gov (United States)

    Fontenot, Jonas D.; Bloch, Charles; Followill, David; Titt, Uwe; Newhauser, Wayne D.

    2010-12-01

    Theoretical calculations have shown that proton therapy can reduce the incidence of radiation-induced secondary malignant neoplasms (SMN) compared with photon therapy for patients with prostate cancer. However, the uncertainties associated with calculations of SMN risk had not been assessed. The objective of this study was to quantify the uncertainties in projected risks of secondary cancer following contemporary proton and photon radiotherapies for prostate cancer. We performed a rigorous propagation of errors and several sensitivity tests to estimate the uncertainty in the ratio of relative risk (RRR) due to the largest contributors to the uncertainty: the radiation weighting factor for neutrons, the dose-response model for radiation carcinogenesis and interpatient variations in absorbed dose. The interval of values for the radiation weighting factor for neutrons and the dose-response model were derived from the literature, while interpatient variations in absorbed dose were taken from actual patient data. The influence of each parameter on a baseline RRR value was quantified. Our analysis revealed that the calculated RRR was insensitive to the largest contributors to the uncertainty. Uncertainties in the radiation weighting factor for neutrons, the shape of the dose-risk model and interpatient variations in therapeutic and stray doses introduced a total uncertainty of 33% to the baseline RRR calculation.

  20. SU-E-T-407: Evaluation of the Stopping Power and Imaging Visibility for Iodine Based Contrast in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Singh, H; Zhao, L; Rana, S; Chacko, M; Zheng, Y [Procure Proton Therapy Center, Oklahoma City, OK (United States)

    2015-06-15

    Purpose: The purpose of this study was to investigate the difference between calculated and measured relative linear stopping power (RLSP) for contrast medium in proton therapy. Furthermore, the visibility for different concentrations in prostate phantom on orthogonal X-ray system was evaluated Methods and Materials: In prostate cancer patient, rectal balloon along with the contrast media was used to visualize the balloon position, thus facilitating the patient setup during each fraction of the uniform scanning proton treatment. There were no fiducial markers implanted in the prostate for this patient. A blue wax phantom with outer dimensions 10cm(H) x 14.5cm(L) x 10cm(W) was made in house. To hold iodine based contrast solution, a rectangular shaped hole with dimensions 7cm(H) x 8cm(L) x 4cm(W) was made inside the phantom. Organically bound 8.5% iodine based Cystografin Dilute contrast agent with molecular formula C11H9I3N2O4.C7H17NO5 was used in this study. Six solutions were prepared; each mixture of water and iodine based contrast agent at different concentrations as 0%, 5%, 10%, 20%, 30% and 50%. During computed tomographic(CT) simulation, solutions were placed together at the isocenter of CT and scanned at 120kVp using the same protocol as for prostate cancer patients. The treatment planning was done in CMS-XiO system. Multi-layer-ion-chamber (MLIC) was used to measure residual proton range. Results: The 50% concentration contrast solution was used during treatment for better visualization on orthogonal X-ray image. The measured RLSP for 5%, 10%, 20%, 30% & 50% solutions were 1.005, 1.010, 1.018, 1.023 & 1.033; and similarly calculated RLSP from XiO were 1.090, 1.135, 1.222, 1.299 & 1.448 respectively. Conclusion: The treatment planning system could overestimates the relative stopping power of contrast solution with high concentrations. It is recommended to override the contrast with measured RLSP for high atomic number based contrast solution in treatment

  1. Proton Radiation Therapy for Pediatric Medulloblastoma and Supratentorial Primitive Neuroectodermal Tumors: Outcomes for Very Young Children Treated With Upfront Chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, Rachel B., E-mail: rbjimenez@partners.org [Harvard Radiation Oncology Program, Boston, Massachusetts (United States); Sethi, Roshan [Harvard Medical School, Boston, Massachusetts (United States); Depauw, Nicolas [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Pulsifer, Margaret B. [Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts (United States); Adams, Judith [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); McBride, Sean M. [Harvard Radiation Oncology Program, Boston, Massachusetts (United States); Ebb, David [Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts (United States); Fullerton, Barbara C.; Tarbell, Nancy J.; Yock, Torunn I.; MacDonald, Shannon M. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2013-09-01

    Purpose: To report the early outcomes for very young children with medulloblastoma or supratentorial primitive neuroectodermal tumor (SPNET) treated with upfront chemotherapy followed by 3-dimensional proton radiation therapy (3D-CPT). Methods and Materials: All patients aged <60 months with medulloblastoma or SPNET treated with chemotherapy before 3D-CPT from 2002 to 2010 at our institution were included. All patients underwent maximal surgical resection, chemotherapy, and adjuvant 3D-CPT with either craniospinal irradiation followed by involved-field radiation therapy or involved-field radiation therapy alone. Results: Fifteen patients (median age at diagnosis, 35 months) were treated with high-dose chemotherapy and 3D-CPT. Twelve of 15 patients had medulloblastoma; 3 of 15 patients had SPNET. Median time from surgery to initiation of radiation was 219 days. Median craniospinal irradiation dose was 21.6 Gy (relative biologic effectiveness); median boost dose was 54.0 Gy (relative biologic effectiveness). At a median of 39 months from completion of radiation, 1 of 15 was deceased after a local failure, 1 of 15 had died from a non-disease-related cause, and the remaining 13 of 15 patients were alive without evidence of disease recurrence. Ototoxicity and endocrinopathies were the most common long-term toxicities, with 2 of 15 children requiring hearing aids and 3 of 15 requiring exogenous hormones. Conclusions: Proton radiation after chemotherapy resulted in good disease outcomes for a small cohort of very young patients with medulloblastoma and SPNET. Longer follow-up and larger numbers of patients are needed to assess long-term outcomes and late toxicity.

  2. Benchmarking of a treatment planning system for spot scanning proton therapy: Comparison and analysis of robustness to setup errors of photon IMRT and proton SFUD treatment plans of base of skull meningioma

    Energy Technology Data Exchange (ETDEWEB)

    Harding, R., E-mail: ruth.harding2@wales.nhs.uk [St James’s Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF, United Kingdomand Abertawe Bro Morgannwg University Health Board, Medical Physics and Clinical Engineering, Swansea SA2 8QA (United Kingdom); Trnková, P.; Lomax, A. J. [Paul Scherrer Institute, Centre for Proton Therapy, Villigen 5232 (Switzerland); Weston, S. J.; Lilley, J.; Thompson, C. M.; Cosgrove, V. P. [St James’s Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF (United Kingdom); Short, S. C. [Leeds Institute of Molecular Medicine, Oncology and Clinical Research, Leeds LS9 7TF, United Kingdomand St James’s Institute of Oncology, Oncology, Leeds LS9 7TF (United Kingdom); Loughrey, C. [St James’s Institute of Oncology, Oncology, Leeds LS9 7TF (United Kingdom); Thwaites, D. I. [St James’s Institute of Oncology, Medical Physics and Engineering, Leeds LS9 7TF, United Kingdomand Institute of Medical Physics, School of Physics, University of Sydney, Sydney NSW 2006 (Australia)

    2014-11-01

    Purpose: Base of skull meningioma can be treated with both intensity modulated radiation therapy (IMRT) and spot scanned proton therapy (PT). One of the main benefits of PT is better sparing of organs at risk, but due to the physical and dosimetric characteristics of protons, spot scanned PT can be more sensitive to the uncertainties encountered in the treatment process compared with photon treatment. Therefore, robustness analysis should be part of a comprehensive comparison between these two treatment methods in order to quantify and understand the sensitivity of the treatment techniques to uncertainties. The aim of this work was to benchmark a spot scanning treatment planning system for planning of base of skull meningioma and to compare the created plans and analyze their robustness to setup errors against the IMRT technique. Methods: Plans were produced for three base of skull meningioma cases: IMRT planned with a commercial TPS [Monaco (Elekta AB, Sweden)]; single field uniform dose (SFUD) spot scanning PT produced with an in-house TPS (PSI-plan); and SFUD spot scanning PT plan created with a commercial TPS [XiO (Elekta AB, Sweden)]. A tool for evaluating robustness to random setup errors was created and, for each plan, both a dosimetric evaluation and a robustness analysis to setup errors were performed. Results: It was possible to create clinically acceptable treatment plans for spot scanning proton therapy of meningioma with a commercially available TPS. However, since each treatment planning system uses different methods, this comparison showed different dosimetric results as well as different sensitivities to setup uncertainties. The results confirmed the necessity of an analysis tool for assessing plan robustness to provide a fair comparison of photon and proton plans. Conclusions: Robustness analysis is a critical part of plan evaluation when comparing IMRT plans with spot scanned proton therapy plans.

  3. SU-D-304-04: Pre-Clinical Feasibility Study for Intensity Modulated Grid Proton Therapy (IMgPT) Using a Newly Developed Delivery System

    Energy Technology Data Exchange (ETDEWEB)

    Tsiamas, P; Moskvin, V; Shin, J; Axente, M; Pirlepesov, F; Krasin, M; Merchant, T; Farr, J [St. Jude Children’s Research Hospital, Memphis, TN (United States)

    2015-06-15

    Purpose: The purpose of the current study was to characterize and evaluate intensity-modulated proton grid therapy (IMgPT) using a clinical proton beam. Methods: A TOPAS MC model of a new developmental mode (pre-clinical) of the Hitachi proton therapy system (PROBEAT) was used for simulation and characterization of proton grid therapy. TOPAS simulations of different energy ranges, depths and spot separation distances were performed. LET spectra for various energies and depths were produced with FLUKA MC code for evaluation potential interplay between planning parameters and their effect on the characterization of areas (valley) between spots. IMgPT planning aspects (spot spacing, skin dose, peak-to-valley ratios, beam selection, etc.) were evaluated for different phantom and patient cases. Raysearch software (v4.51) was used to perform the evaluation. Results: Calculated beam peak-to-valley ratios scenarios showed strong energy and depth dependence with ratios to be larger for higher energies and shallower depths. Peak-to-valley ratios for R90 range and for spot spacing of 1cm varied from 30% (E = 221.3 MeV, depth 30.6 cm) to 80% (E = 70.3 MeV, depth 4 cm). LET spectra calculations showed spectral hardening with depth, which might potential increase, spot separation distance and improve peak-to-valley ratios. IMgPT optimization, using constant spot spacing, showed skin dose reduction between peak regions of dose due to the irradiation of less skin. Single beam for bulky shallower tumors might be a potential candidate for proton grid therapy. Conclusions: Proton grid therapy using a clinical beam is a promising technique that reduces skin dose between peak regions of dose and may be suitable for the treatment of shallow tumors. IMgPT may be considered for use when bystander effects in off peak regions would be appropriate.

  4. A Monte Carlo Study of the Relationship between the Time Structures of Prompt Gammas and in vivo Radiation Dose in Proton Therapy

    CERN Document Server

    Shin, Wook-Geun; Shin, Jae-Ik; Jeong, Jong Hwi; Lee, Se Byeong

    2015-01-01

    For the in vivo range verification in proton therapy, it has been tried to measure the spatial distribution of the prompt gammas generated by the proton-induced interactions with the close relationship with the proton dose distribution. However, the high energy of the prompt gammas and background gammas are still problematic in measuring the distribution. In this study, we suggested a new method determining the in vivo range by utilizing the time structure of the prompt gammas formed with the rotation of a range modulation wheel (RMW) in the passive scattering proton therapy. To validate the Monte Carlo code simulating the proton beam nozzle, axial percent depth doses (PDDs) were compared with the measured PDDs with the varying beam range of 4.73-24.01 cm. And the relationship between the proton dose rate and the time structure of the prompt gammas was assessed and compared in the water phantom. The results of the PDD showed accurate agreement within the relative errors of 1.1% in the distal range and 2.9% in...

  5. Water equivalent path length calculations using scatter-corrected head and neck CBCT images to evaluate patients for adaptive proton therapy

    Science.gov (United States)

    Kim, Jihun; Park, Yang-Kyun; Sharp, Gregory; Busse, Paul; Winey, Brian

    2017-01-01

    Proton therapy has dosimetric advantages due to the well-defined range of the proton beam over photon radiotherapy. When the proton beams, however, are delivered to the patient in fractionated radiation treatment, the treatment outcome is affected by delivery uncertainties such as anatomic change in the patient and daily patient setup error. This study aims at establishing a method to evaluate the dosimetric impact of the anatomic change and patient setup error during head and neck proton therapy. Range variations due to the delivery uncertainties were assessed by calculating water equivalent path length (WEPL) to the distal edge of tumor volume using planning CT and weekly treatment cone-beam CT (CBCT) images. Specifically, mean difference and root mean squared deviation (RMSD) of the distal WEPLs were calculated as the weekly range variations. To accurately calculate the distal WEPLs, an existing CBCT scatter correction algorithm was used. An automatic rigid registration was used to align the planning CT and treatment CBCT images, simulating a six degree-of-freedom couch correction at treatments. The authors conclude that the dosimetric impact of the anatomic change and patient setup error was reasonably captured in the differences of the distal WEPL variation with a range calculation uncertainty of 2%. The proposed method to calculate the distal WEPL using the scatter-corrected CBCT images can be an essential tool to decide the necessity of re-planning in adaptive proton therapy.

  6. Long-term proton pump inhibitor therapy and falls and fractures in elderly women: a prospective cohort study.

    Science.gov (United States)

    Lewis, Joshua R; Barre, Deka; Zhu, Kun; Ivey, Kerry L; Lim, Ee Mun; Hughes, Jeff; Prince, Richard L

    2014-11-01

    Proton pump inhibitors (PPIs) are widely used in the elderly. Recent studies have suggested that long-term PPI therapy is associated with fractures in the elderly, however the mechanism remains unknown. We investigated the association between long-term PPI therapy ≥1 year and fracture risk factors including bone structure, falls, and balance-related function in a post hoc analysis of a longitudinal population-based prospective cohort of elderly postmenopausal women and replicated the findings in a second prospective study of falling in elderly postmenopausal women. Long-term PPI therapy was associated with increased risk of falls and fracture-related hospitalizations; adjusted odds ratio (AOR) 2.17; 95% CI, 1.25-3.77; p = 0.006 and 1.95; 95% CI, 1.20-3.16; p = 0.007, respectively. In the replication study, long-term PPI use was associated with an increased risk of self-reported falling; AOR, 1.51; 95% CI, 1.00-2.27; p = 0.049. No association of long-term PPI therapy with bone structure was observed; however, questionnaire-assessed falls-associated metrics such as limiting outdoor activity (p = 0.002) and indoor activity (p = 0.001) due to fear of falling, dizziness (p elderly women, already at high risk of fracture, appears to be mediated via increased falls risk and falling rather than impaired bone structure and should be carefully considered when prescribing long-term PPI therapy.

  7. SU-E-J-222: Feasibility Study of MRI-Only Proton Therapy Planning

    Energy Technology Data Exchange (ETDEWEB)

    Spadea, M [ImagEngLab, Magna Graecia University, Catanzaro (Italy); Izquierdo, D; Catana, C [Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA (United States); Collins-Fekete, C; Bortfeld, T; Seco, J [Massachusetts General Hospital, Harvard Medical, Boston, MA (United States)

    2015-06-15

    Purpose: To assess the dosimetric equivalence of MRI based proton planning vs. single energy x-ray CT. Methods: 8 glioblastoma patients were imaged with CT and MRI after surgical resection. T1-weighted 3DMPRAGE was used to delineate the GTV, which was subsequently rigidly registered to the CT volume. A pseudoCT was generated from the aligned MRI by combining segmentation and atlas-based approaches. The spatial resolution both for pseudo- and real CT was 0.6×0.6×2.5mm. Three orthogonal proton beams were simulated on the pseudoCT. Two co-planar beams were set on the axial plane. The third one was planned parallel to the cranio-caudal (CC) direction. Each beam was set to cover the GTV at 98% of the nominal dose (18Gy). The proton plan was copied and transferred to the real CT, including aperture/compensator geometry. Dose comparison between pseudoCT and CT plan was performed beam-by-beam by quantifying the range shift of dose profile on each slice of the GTV. The GTV’s V{sub 98} was computed for the CT. Results: For beams in axial plane the median absolute value of the range shift was 0.3mm, with 0.9mm and 1.4mm as 95th percentile and maximum, respectively. Worst scenarios were found for the CC beam, where we measured 1.1mm (median), 2.7mm (95thpercentile) and 5mm (maximum). Regardless the direction, beams passing through the surgical site, where metal (Titanium MRI-compatible) staples were present, were mostly affected by range shift. GTV’s V{sub 98} for CT was not lower than 99.3%. Conclusion: The study showed the clinical feasibility of an MRI-alone proton plan. Advantages include the possibility to rely on better soft tissue contrast for target and organs at risk delineation without the need of further CT scan and image registration. Additional investigation is required in presence of metal implants along the beam path and to account for partial volume effects due to slice thickness.

  8. Evaluation of open MPI and MPICH2 performances for the computation time in proton therapy dose calculations with Geant4

    Science.gov (United States)

    Kazemi, M.; Afarideh, H.; Riazi, Z.

    2015-11-01

    The aim of this research work is to use a better parallel software structure to improve the performance of the Monte Carlo Geant4 code in proton treatment planning. The hadron therapy simulation is rewritten to parallelize the shared memory multiprocessor systems by using the Message-Passing Interface (MPI). The speedup performance of the code has been studied by using two MPI-compliant libraries including Open MPI and the MPICH2, separately. Despite the speedup, the results are almost linear for both the Open MPI and MPICH2; the latter was chosen because of its better characteristics and lower computation time. The Geant4 parameters, including the step limiter and the set cut, have been analyzed to minimize the simulation time as much as possible. For a reasonable compromise between the spatial dose distribution and the calculation time, the improvement in time reduction coefficient reaches about 157.

  9. Five-year outcomes from a prospective trial of image-guided accelerated hypofractionated proton therapy for prostate cancer.

    Science.gov (United States)

    Henderson, Randal H; Bryant, Curtis; Hoppe, Bradford S; Nichols, R Charles; Mendenhall, William M; Flampouri, Stella; Su, Zhong; Li, Zuofeng; Morris, Christopher G; Mendenhall, Nancy P

    2017-07-01

    To report 5-year outcomes of a prospective trial of image-guided accelerated hypofractionated proton therapy (AHPT) for prostate cancer. 215 prostate cancer patients accrued to a prospective institutional review board-approved trial of 70Gy(RBE) in 28 fractions for low-risk disease (n = 120) and 72.5Gy(RBE) in 29 fractions for intermediate-risk disease (n = 95). This trial excluded patients with prostate volumes of ≥60 cm(3) or International Prostate Symptom Scores (IPSS) of ≥15, patients on anticoagulants or alpha-blockers, and patients in whom dose-constraint goals for organs at risk (OAR) could not be met. Toxicities were graded prospectively according to Common Terminology Criteria for Adverse Events (CTCAE), version 3.0. This trial can be found on ClinicalTrials.gov (NCT00693238). Median follow-up was 5.2 years. Five-year rates of freedom from biochemical and clinical disease progression were 95.9%, 98.3%, and 92.7% in the overall group and the low- and intermediate-risk subsets, respectively. Actuarial 5-year rates of late radiation-related CTCAE v3.0 grade 3 or higher gastrointestinal and urologic toxicities were 0.5% and 1.7%, respectively. Median IPSS before treatment and at 4+ years after treatment were 6 and 5 for low-risk patients and 4 and 6 for intermediate-risk patients. Image-guided AHPT 5-year outcomes show high efficacy and minimal physician-assessed toxicity in selected patients. These results are comparable to the 5-year results of our prospective trials of standard fractionated proton therapy for patients with low-risk and intermediate-risk prostate cancer. Longer follow-up and a larger cohort are necessary to confirm these findings.

  10. TPSPET—A TPS-based approach for in vivo dose verification with PET in proton therapy

    Science.gov (United States)

    Frey, K.; Bauer, J.; Unholtz, D.; Kurz, C.; Krämer, M.; Bortfeld, T.; Parodi, K.

    2014-01-01

    Since the interest in ion-irradiation for tumour therapy has significantly increased over the last few decades, intensive investigations are performed to improve the accuracy of this form of patient treatment. One major goal is the development of methods for in vivo dose verification. In proton therapy, a PET (positron emission tomography)-based approach measuring the irradiation-induced tissue activation inside the patient has been already clinically implemented. The acquired PET images can be compared to an expectation, derived under the assumption of a correct treatment application, to validate the particle range and the lateral field position in vivo. In the context of this work, TPSPET is introduced as a new approach to predict proton-irradiation induced three-dimensional positron emitter distributions by means of the same algorithms of the clinical treatment planning system (TPS). In order to perform additional activity calculations, reaction-channel-dependent input positron emitter depth distributions are necessary, which are determined from the application of a modified filtering approach to the TPS reference depth dose profiles in water. This paper presents the implementation of TPSPET on the basis of the research treatment planning software treatment planning for particles. The results are validated in phantom and patient studies against Monte Carlo simulations, and compared to β+-emitter distributions obtained from a slightly modified version of the originally proposed one-dimensional filtering approach applied to three-dimensional dose distributions. In contrast to previously introduced methods, TPSPET provides a faster implementation, the results show no sensitivity to lateral field extension and the predicted β+-emitter densities are fully consistent to the planned treatment dose as they are calculated by the same pencil beam algorithms. These findings suggest a large potential of the application of TPSPET for in vivo dose verification in the daily

  11. Inter-comparison of relative stopping power estimation models for proton therapy

    Science.gov (United States)

    Doolan, P. J.; Collins-Fekete, Charles-Antoine; Dias, Marta F.; Ruggieri, Thomas A.; D'Souza, Derek; Seco, Joao

    2016-11-01

    Theoretical stopping power values were inter-compared for the Bichsel, Janni, ICRU and Schneider relative stopping power (RSP) estimation models, for a variety of tissues and tissue substitute materials taken from the literature. The RSPs of eleven plastic tissue substitutes were measured using Bragg peak shift measurements in water in order to establish a gold standard of RSP values specific to our centre’s proton beam characteristics. The theoretical tissue substitute RSP values were computed based on literature compositions to assess the four different computation approaches. The Bichsel/Janni/ICRU approaches led to mean errors in the RSP of  -0.1/+0.7/-0.8%, respectively. Errors when using the Schneider approach, with I-values from the Bichsel, Janni and ICRU sources, followed the same pattern but were generally larger. Following this, the mean elemental ionisation energies were optimized until the differences between theoretical RSP values matched measurements. Failing to use optimized I-values when applying the Schneider technique to 72 human tissues could introduce errors in the RSP of up to  -1.7/+1.1/-0.4% when using Bichsel/Janni/ICRU I-values, respectively. As such, it may be necessary to introduce an additional step in the current stoichiometric calibration procedure in which tissue insert RSPs are measured in a proton beam. Elemental I-values can then optimized to match these measurements, reducing the uncertainty when calculating human tissue RSPs.

  12. Control of the slow extraction process in a dedicated proton synchrotron for hadron therapy

    CERN Document Server

    Molodozhentsev, A Yu

    1999-01-01

    The ring design of the synchrotron for cancer treatment, based on the third-order resonant extraction, was been performed to meet the special medical requirements. The uniformity of the slow extracted beam from the proton synchrotron is the main requirement on the beam quality determined by the medical application. The smooth extraction during at least 400 msec should be realized for the `raster' scanning of tumours. Control of the slow extraction over the whole spill time is discussed in this report. To keep all lattice functions of the ring constant during the extraction a slow movement of the accelerated particles into the resonance can be used. To reduce degradation of the uniformity of the extracted beam by ripples from the power converters of the magnetic elements, the RF empty-bucket channeling method should be utilized. This method allows reduce the ripple influence during slow extraction. Both methods are analyzed to control the slow extraction for the dedicated proton synchrotron. The main parameter...

  13. Robustness of the Voluntary Breath-Hold Approach for the Treatment of Peripheral Lung Tumors Using Hypofractionated Pencil Beam Scanning Proton Therapy

    DEFF Research Database (Denmark)

    Dueck, Jenny; Knopf, Antje-Christin; Lomax, Antony

    2016-01-01

    PURPOSE: The safe clinical implementation of pencil beam scanning (PBS) proton therapy for lung tumors is complicated by the delivery uncertainties caused by breathing motion. The purpose of this feasibility study was to investigate whether a voluntary breath-hold technique could limit the delivery...

  14. Extension and validation of an analytical model for in vivo PET verification of proton therapy--a phantom and clinical study

    NARCIS (Netherlands)

    Attanasi, F; Knopf, A; Parodi, K.; Paganetti, Harald; Bortfeld, Thomas; Rosso, V; Del Guerra, Alberto

    2011-01-01

    The interest in positron emission tomography (PET) as a tool for treatment verification in proton therapy has become widespread in recent years, and several research groups worldwide are currently investigating the clinical implementation. After the first off-line investigation with a PET/CT scanner

  15. Measurements of thermal neutron fluence proton therapy for head and neck; Medidas de la fluencia de neutrones termicos en protonterapia de cabeza y cuello

    Energy Technology Data Exchange (ETDEWEB)

    Lagares, J. I.; Sansaloni, F.; Terron, J. A.; Muniz, J. L.; Exposito, M. r.; Nieto-Camero, J.J.; Korf, A.; Arce, P.; Nunez, L.; Loubser, M.; Sanchez-Doblado, F.

    2011-07-01

    We present an estimate of the distribution of thermal neutron fluence proton therapy for head and neck using an anthropomorphic phantom called NORMA. It also represents a small part within a larger project which aims to develop a risk prediction model due to neutron radiation generated indirectly in radiotherapy.

  16. Short-lived positron emitters in beam-on PET imaging during proton therapy

    Science.gov (United States)

    Dendooven, P.; Buitenhuis, H. J. T.; Diblen, F.; Heeres, P. N.; Biegun, A. K.; Fiedler, F.; van Goethem, M.-J.; van der Graaf, E. R.; Brandenburg, S.

    2015-12-01

    The only method for in vivo dose delivery verification in proton beam radiotherapy in clinical use today is positron emission tomography (PET) of the positron emitters produced in the patient during irradiation. PET imaging while the beam is on (so called beam-on PET) is an attractive option, providing the largest number of counts, the least biological washout and the fastest feedback. In this implementation, all nuclides, independent of their half-life, will contribute. As a first step towards assessing the relevance of short-lived nuclides (half-life shorter than that of 10C, T1/2  =  19 s) for in vivo dose delivery verification using beam-on PET, we measured their production in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: 12N (T1/2  =  11 ms) on carbon (9% of 11C), 29P (T1/2  =  4.1 s) on phosphorus (20% of 30P) and 38mK (T1/2  =  0.92 s) on calcium (113% of 38gK). No short-lived nuclides are produced on oxygen. The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, 12N dominates up to 70 s. On bone tissue, 12N dominates over 15O during the first 8-15 s (depending on carbon-to-oxygen ratio). The short-lived nuclides created on phosphorus and calcium provide 2.5 times more beam-on PET counts than the long-lived ones produced on these elements during a 70 s irradiation. From the estimated number of 12N PET counts, we conclude that, for any tissue, 12N PET imaging potentially provides equal to superior proton range information compared to prompt gamma imaging with an optimized knife-edge slit camera. The practical implementation of 12N PET imaging is discussed.

  17. Intensity-Modulated Proton Therapy Further Reduces Normal Tissue Exposure During Definitive Therapy for Locally Advanced Distal Esophageal Tumors: A Dosimetric Study

    Energy Technology Data Exchange (ETDEWEB)

    Welsh, James, E-mail: jwelsh@mdanderson.org [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Gomez, Daniel; Palmer, Matthew B.; Riley, Beverly A.; Mayankkumar, Amin V.; Komaki, Ritsuko [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Dong, Lei; Zhu, X. Ronald [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Likhacheva, Anna; Liao, Zhongxing [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Hofstetter, Wayne L. [Department of Thoracic and Cardiovascular Surgery, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Ajani, Jaffer A. [Department of Gastrointestinal Medical Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Cox, James D. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

    2011-12-01

    Purpose: We have previously found that {<=} 75% of treatment failures after chemoradiotherapy for unresectable esophageal cancer appear within the gross tumor volume and that intensity-modulated (photon) radiotherapy (IMRT) might allow dose escalation to the tumor without increasing normal tissue toxicity. Proton therapy might allow additional dose escalation, with even lower normal tissue toxicity. In the present study, we compared the dosimetric parameters for photon IMRT with that for intensity-modulated proton therapy (IMPT) for unresectable, locally advanced, distal esophageal cancer. Patients and Methods: Four plans were created for each of 10 patients. IMPT was delivered using anteroposterior (AP)/posteroanterior beams, left posterior oblique/right posterior oblique (LPO/RPO) beams, or AP/LPO/RPO beams. IMRT was delivered with a concomitant boost to the gross tumor volume. The dose was 65.8 Gy to the gross tumor volume and 50.4 Gy to the planning target volume in 28 fractions. Results: Relative to IMRT, the IMPT (AP/posteroanterior) plan led to considerable reductions in the mean lung dose (3.18 vs. 8.27 Gy, p < .0001) and the percentage of lung volume receiving 5, 10, and 20 Gy (p {<=} .0006) but did not reduce the cardiac dose. The IMPT LPO/RPO plan also reduced the mean lung dose (4.9 Gy vs. 8.2 Gy, p < .001), the heart dose (mean cardiac dose and percentage of the cardiac volume receiving 10, 20, and 30 Gy, p {<=} .02), and the liver dose (mean hepatic dose 5 Gy vs. 14.9 Gy, p < .0001). The IMPT AP/LPO/RPO plan led to considerable reductions in the dose to the lung (p {<=} .005), heart (p {<=} .003), and liver (p {<=} .04). Conclusions: Compared with IMRT, IMPT for distal esophageal cancer lowered the dose to the heart, lung, and liver. The AP/LPO/RPO beam arrangement was optimal for sparing all three organs. The dosimetric benefits of protons will need to be tailored to each patient according to their specific cardiac and pulmonary risks. IMPT for

  18. Endocrine function following high dose proton therapy for tumors of the upper clivus

    Energy Technology Data Exchange (ETDEWEB)

    Slater, J.D.; Austin-Seymour, M.; Munzenrider, J.; Birnbaum, S.; Carroll, R.; Klibanski, A.; Riskind, P.; Urie, M.; Verhey, L.; Goitein, M.

    1988-09-01

    The endocrine status of patients receiving proton radiation for tumors of the upper clivus was reviewed to evaluate the effect of high dose treatment on the pituitary gland. The fourteen patients had chordomas or low grade chondrosarcomas and were all treated by the same techniques. The median tumor dose was 69.7 Cobalt Gray Equivalent (CGE) with a range from 66.6 to 74.4 CGE. (CGE is used because modulated protons have an RBE of 1.1 compared to 60Co). The daily fraction size was 1.8-2.1 CGE. The median follow-up time is 48 months, ranging from 30 to 68 months. All treatments were planned using a computerized multi-dimensional system with the position of the pituitary outlined on the planning CT scan. Review of the dose distribution indicated that the dose to the pituitary ranged from 60.5 to 72.3 CGE, with a median of 67.6 CGE. One female patient had decreased thyroid and gonadotropin function at the time of diagnosis and has been on hormone replacement since that time. The other three females were all pre-menopausal at the time of radiotherapy. At this time four patients (3 males and 1 female) have developed endocrine abnormalities 14 to 45 months after irradiation. All four had evidence of hypothyroidism and two have also developed corticotropin deficiency. The three males had decreased testosterone levels; the female patient developed amenorrhea and hyperprolactinemia. All four are asymptomatic with ongoing hormone replacement.

  19. A beam monitoring and validation system for continuous line scanning in proton therapy

    Science.gov (United States)

    Klimpki, G.; Psoroulas, S.; Bula, C.; Rechsteiner, U.; Eichin, M.; Weber, D. C.; Lomax, A.; Meer, D.

    2017-08-01

    Line scanning represents a faster and potentially more flexible form of pencil beam scanning than conventional step-and-shoot irradiations. It seeks to minimize dead times in beam delivery whilst preserving the possibility of modulating the dose at any point in the target volume. Our second generation proton gantry features irradiations in line scanning mode, but it still lacks a dedicated monitoring and validation system that guarantees patient safety throughout the irradiation. We report on its design and implementation in this paper. In line scanning, we steer the proton beam continuously along straight lines while adapting the speed and/or current frequently to modulate the delivered dose. We intend to prevent delivery errors that could be clinically relevant through a two-stage system: safety level 1 monitors the beam current and position every 10 μs. We demonstrate that direct readings from ionization chambers in the gantry nozzle and Hall probes in the scanner magnets provide required information on current and position, respectively. Interlocks will be raised when measured signals exceed their predefined tolerance bands. Even in case of an erroneous delivery, safety level 1 restricts hot and cold spots of the physically delivered fraction dose to  ±36~mGy (±2% of 2~Gy biologically). In safety level 2—an additional, partly redundant validation step—we compare the integral line profile measured with a strip monitor in the nozzle to a forward-calculated prediction. The comparison is performed between two line applications to detect amplifying inaccuracies in speed and current modulation. This level can be regarded as an online quality assurance of the machine. Both safety levels use devices and functionalities already installed along the beamline. Hence, the presented monitoring and validation system preserves full compatibility of discrete and continuous delivery mode on a single gantry, with the possibility of switching between modes during the

  20. SU-E-T-288: Dose Volume Population Histogram (DVPH): A New Method to Evaluate Intensity Modulated Proton Therapy Plans With Geometrical Uncertainties

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, T; Mai, N [University of Science, Ho Chi Minh City (Viet Nam); Nguyen, B [Prowess Inc, Concord, CA (United States)

    2015-06-15

    Purpose: In Proton therapy, especially intensity modulated proton therapy(IMPT), the dose distribution shape is very sensitive to errors due to sharp dose gradients at the Bragg peaks. The concept of the conventional margin is based on the assumption that dose distribution is shifted rather than deformed due to geometrical uncertainties. The goal of this study is to access the validity of the margin concept as well as propose a new approach using Dose Volume Population Histogram (DVPH) in evaluating IMPT plans. Methods: For a prostate case, an intensity modulated proton therapy is optimized based on the conventional PTV based objective function. The plan is evaluated based on the PTV DVH and CTV DVPH (dose volume population histogram) which explicitly taking into account geometric uncertainties. The DVPH is calculated based on 2197 dose distributions at different CTV possible positions for both random and systematic errors. The DVPH with a 90% confidence level is used for the comparison. Results: The minimum dose of the CTV DVPH with a 90% confidence level is only about 18% of the prescribed dose, while the minimum dose of the PTV is 95%. For bladder DVHs, the D50 and D35 is 26% and 30%, compared to 65% and 70% of the prescribed dose from the bladder DVPH with 90% confidence level. Conclusion: The results showed that the PTV concept for ensuring the prescribed dose actually delivered to the CTV is invalid in proton therapy. The good PTV DVH might Result in an underdose to the target and should not be used for IMPT optimization. For OARs, the conventional evaluation approach underestimates dose volume end points. The new concept DVPH has been proved to provide a more accurate DVH evaluation in proton therapy.

  1. SU-E-T-628: Predicted Risk of Post-Irradiation Cerebral Necrosis in Pediatric Brain Cancer Patients: A Treatment Planning Comparison of Proton Vs. Photon Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Freund, D [Willis Knighton Cancer Center, Shreveport, LA (United States); Zhang, R; Sanders, M [Mary Bird Perkins Cancer Center, Baton Rouge, LA (United States); Newhauser, W [Louisiana State University, Baton Rouge, LA (United States)

    2015-06-15

    Purpose: Post-irradiation cerebral necrosis (PICN) is a severe late effect that can Result from brain cancers treatment using radiation therapy. The purpose of this study was to compare the treatment plans and predicted risk of PICN after volumetric modulated arc therapy (VMAT) to the risk after passively scattered proton therapy (PSPT) and intensity modulated proton therapy (IMPT) in a cohort of pediatric patients. Methods: Thirteen pediatric patients with varying age and sex were selected for this study. A clinical treatment volume (CTV) was constructed for 8 glioma patients and 5 ependymoma patients. Prescribed dose was 54 Gy over 30 fractions to the planning volume. Dosimetric endpoints were compared between VMAT and proton plans. The normal tissue complication probability (NTCP) following VMAT and proton therapy planning was also calculated using PICN as the biological endpoint. Sensitivity tests were performed to determine if predicted risk of PICN was sensitive to positional errors, proton range errors and selection of risk models. Results: Both PSPT and IMPT plans resulted in a significant increase in the maximum dose and reduction in the total brain volume irradiated to low doses compared with the VMAT plans. The average ratios of NTCP between PSPT and VMAT were 0.56 and 0.38 for glioma and ependymoma patients respectively and the average ratios of NTCP between IMPT and VMAT were 0.67 and 0.68 for glioma and ependymoma plans respectively. Sensitivity test revealed that predicted ratios of risk were insensitive to range and positional errors but varied with risk model selection. Conclusion: Both PSPT and IMPT plans resulted in a decrease in the predictive risk of necrosis for the pediatric plans studied in this work. Sensitivity analysis upheld the qualitative findings of the risk models used in this study, however more accurate models that take into account dose and volume are needed.

  2. Distributions of positron-emitting nuclei in proton and carbon-ion therapy studied with GEANT4

    CERN Document Server

    Pshenichnov, I; Mishustin, I; Greiner, Walter; Mishustin, Igor; Pshenichnov, Igor

    2006-01-01

    Depth distributions of positron-emitting nuclei in PMMA phantoms are calculated within a Monte Carlo model for Heavy-Ion Therapy (MCHIT) based on the GEANT4 toolkit (version 8.0). The calculated total production rates of $^{11}$C, $^{10}$C and $^{15}$O nuclei are compared with the corresponding results of the FLUKA code and with experimental data. The distributions of e$^+$ annihilation points are obtained by simulating radioactive decay of unstable nuclei and transporting positrons in surrounding medium. A finite spatial resolution of the Positron Emission Tomography (PET) is taken into account in a simplified way. Depth distributions of $\\beta^+$-activity as seen by a PET scanner are calculated and compared to available data for PMMA phantoms. The calculated $\\beta^+$-activity profiles are in good agreement with PET data for proton and $^{12}$C beams at energies suitable for particle therapy. The MCHIT capabilities to calculate $\\beta^+$-activity distributions in tissue-like materials of different chemical ...

  3. The use of multi-gap resistive plate chambers for in-beam PET in proton and carbon ion therapy

    CERN Document Server

    Watts, David; Sauli, Fabio; Amaldi, Ugo

    2013-01-01

    On-line verification of the delivered dose during proton and carbon ion radiotherapy is currently a very desirable goal for quality assurance of hadron therapy treatment plans. In-beam positron emission tomography (ibPET), which can provide an image of the β+ activity induced in the patient during irradiation, which in turn is correlated to the range of the ion beam, is one of the modalities for achieving this goal. Application to hadron therapy requires that the scanner geometry be modified from that which is used in nuclear medicine. In particular, PET detectors that allow a sub-nanosecond time-of-flight (TOF) registration of the collinear photons have been proposed. Inclusion of the TOF information in PET data leads to more effective PET sensitivity. Considering the challenges inherent in the ibPET technique, namely limited β+ activity and the effect of biological washout due to blood flow, TOF-PET technologies are very attractive. In this context, the TERA Foundation is investigating the use of resistiv...

  4. PET Scanning Protocols for In-Situ Dose Delivery Verification of Proton Therapy

    NARCIS (Netherlands)

    Buitenhuis, H.J.T.; Dendooven, P.; Biegun, A.K.; van der Borden, A.J.; Diblen, F.; van Goethem, M.-J.; van der Schaaf, A.A.; van t Veld, Aart; Brandenburg, S.

    2016-01-01

    Positron emission tomography is so far the only method for in-vivo dose delivery verification in hadron therapy that is in clinical use. A PET scanner placed in the treatment position (in-situ) will be able to obtain the highest number of counts, as it minimizes the decay of the positron emitting

  5. Performance of MACACO Compton telescope for ion-beam therapy monitoring : first test with proton beams

    NARCIS (Netherlands)

    Solevi, Paola; Munoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosa, Gabriela

    2016-01-01

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector

  6. PET Scanning Protocols for In-Situ Dose Delivery Verification of Proton Therapy

    NARCIS (Netherlands)

    Buitenhuis, H.J.T.; Dendooven, P.; Biegun, A.K.; van der Borden, A.J.; Diblen, F.; van Goethem, M.-J.; van der Schaaf, A.A.; van t Veld, Aart; Brandenburg, S.

    2016-01-01

    Positron emission tomography is so far the only method for in-vivo dose delivery verification in hadron therapy that is in clinical use. A PET scanner placed in the treatment position (in-situ) will be able to obtain the highest number of counts, as it minimizes the decay of the positron emitting nu

  7. Short-lived Positron Emitters in Beam-on PET Imaging During Proton Therapy

    NARCIS (Netherlands)

    Dendooven, P.; Buitenhuis, H.J.T.; Diblen, F.; Biegun, A.K.; Fiedler, F.; van Goethem, M.-Jan; van der Graaf, E.R.; Brandenburg, S.

    2016-01-01

    Positron emission tomography is so far the only method for in-vivo dose delivery verification in hadron therapy that is in clinical use. PET imaging during irradiation maximizes the number of detected counts and minimizes washout. In such a scenario, also short-lived positron emitters will be observ

  8. Proton Radiobiology

    Directory of Open Access Journals (Sweden)

    Francesco Tommasino

    2015-02-01

    Full Text Available In addition to the physical advantages (Bragg peak, the use of charged particles in cancer therapy can be associated with distinct biological effects compared to X-rays. While heavy ions (densely ionizing radiation are known to have an energy- and charge-dependent increased Relative Biological Effectiveness (RBE, protons should not be very different from sparsely ionizing photons. A slightly increased biological effectiveness is taken into account in proton treatment planning by assuming a fixed RBE of 1.1 for the whole radiation field. However, data emerging from recent studies suggest that, for several end points of clinical relevance, the biological response is differentially modulated by protons compared to photons. In parallel, research in the field of medical physics highlighted how variations in RBE that are currently neglected might actually result in deposition of significant doses in healthy organs. This seems to be relevant in particular for normal tissues in the entrance region and for organs at risk close behind the tumor. All these aspects will be considered and discussed in this review, highlighting how a re-discussion of the role of a variable RBE in proton therapy might be well-timed.

  9. Investigating CT to CBCT image registration for head and neck proton therapy as a tool for daily dose recalculation

    Energy Technology Data Exchange (ETDEWEB)

    Landry, Guillaume, E-mail: g.landry@lmu.de [Department of Medical Physics, Ludwig-Maximilians-University, Munich D85748, Germany and Department of Radiation Oncology, Ludwig-Maximilians-University, Munich D81377 (Germany); Nijhuis, Reinoud; Thieke, Christian; Reiner, Michael; Ganswindt, Ute; Belka, Claus [Department of Radiation Oncology, Ludwig-Maximilians-University, Munich D81377 (Germany); Dedes, George; Handrack, Josefine; Parodi, Katia [Department of Medical Physics, Ludwig-Maximilians-University, Munich D85748 (Germany); Janssens, Guillaume; Orban de Xivry, Jonathan [ICTEAM, Université Catholique de Louvain, Louvain-La-Neuve B1348 (Belgium); Kamp, Florian; Wilkens, Jan J. [Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Munich D81675, Germany and Physik-Department, Technische Universität München, Garching D85748 (Germany); Paganelli, Chiara; Riboldi, Marco; Baroni, Guido [Dipartimento di Elettronica Informazione e Bioingegneria, Politecnico di Milano, Milan 20133 (Italy)

    2015-03-15

    Purpose: Intensity modulated proton therapy (IMPT) of head and neck (H and N) cancer patients may be improved by plan adaptation. The decision to adapt the treatment plan based on a dose recalculation on the current anatomy requires a diagnostic quality computed tomography (CT) scan of the patient. As gantry-mounted cone beam CT (CBCT) scanners are currently being offered by vendors, they may offer daily or weekly updates of patient anatomy. CBCT image quality may not be sufficient for accurate proton dose calculation and it is likely necessary to perform CBCT CT number correction. In this work, the authors investigated deformable image registration (DIR) of the planning CT (pCT) to the CBCT to generate a virtual CT (vCT) to be used for proton dose recalculation. Methods: Datasets of six H and N cancer patients undergoing photon intensity modulated radiation therapy were used in this study to validate the vCT approach. Each dataset contained a CBCT acquired within 3 days of a replanning CT (rpCT), in addition to a pCT. The pCT and rpCT were delineated by a physician. A Morphons algorithm was employed in this work to perform DIR of the pCT to CBCT following a rigid registration of the two images. The contours from the pCT were deformed using the vector field resulting from DIR to yield a contoured vCT. The DIR accuracy was evaluated with a scale invariant feature transform (SIFT) algorithm comparing automatically identified matching features between vCT and CBCT. The rpCT was used as reference for evaluation of the vCT. The vCT and rpCT CT numbers were converted to stopping power ratio and the water equivalent thickness (WET) was calculated. IMPT dose distributions from treatment plans optimized on the pCT were recalculated with a Monte Carlo algorithm on the rpCT and vCT for comparison in terms of gamma index, dose volume histogram (DVH) statistics as well as proton range. The DIR generated contours on the vCT were compared to physician-drawn contours on the rp

  10. Effect of titanium dental implants on proton therapy delivered for head tumors: experimental validation using an anthropomorphic head phantom

    Science.gov (United States)

    Oancea, C.; Shipulin, K.; Mytsin, G.; Molokanov, A.; Niculae, D.; Ambrožová, I.; Davídková, M.

    2017-03-01

    A dosimetric experiment was performed at the Medico-Technical Complex in the Joint Institute for Nuclear Research, Dubna, to investigate the effects of metallic dental implants in the treatment of head and neck tumours with proton therapy. The goal of the study was to evaluate the 2D dose distributions of different clinical treatment plans measured in an anthropomorphic phantom, and compare them to predictions from a treatment planning system. The anthropomorphic phantom was sliced into horizontal segments. Two grade 4 Titanium implants were inserted between 2 slices, corresponding to a maxillary area. GafChromic EBT2 films were placed between the segments containing the implants to measure the 2D delivered dose. Two different targets were designed: the first target includes the dental implants in the isocentre, and in the second target, the proton beam is delivered through the implants, which are located at the entrance region of the Bragg curve. The experimental results were compared to the treatment plans made using our custom 3D Treatment Planning System, named RayTreat. To quantitatively determine differences in the isodose distributions (measured and calculated), the gamma index (3 mm, 3%) was calculated for each target for the matrix value in the region of high isodose (> 90%): for the experimental setup, which includes the implants in the SOBP region, the result obtained was 84.3%. When the implants were localised in the entrance region of the Bragg curve, the result obtained was 86.4%. In conclusion, the uncertainties introduced by the clinically planned dose distribution are beyond reasonable limits. The linear energy transfer spectra in close proximity to the implants were investigated using solid state nuclear track detectors (TED). Scattered particles outside the target were detected.

  11. Application of single- and dual-energy CT brain tissue segmentation to PET monitoring of proton therapy

    Science.gov (United States)

    Berndt, Bianca; Landry, Guillaume; Schwarz, Florian; Tessonnier, Thomas; Kamp, Florian; Dedes, George; Thieke, Christian; Würl, Matthias; Kurz, Christopher; Ganswindt, Ute; Verhaegen, Frank; Debus, Jürgen; Belka, Claus; Sommer, Wieland; Reiser, Maximilian; Bauer, Julia; Parodi, Katia

    2017-03-01

    The purpose of this work was to evaluate the ability of single and dual energy computed tomography (SECT, DECT) to estimate tissue composition and density for usage in Monte Carlo (MC) simulations of irradiation induced β + activity distributions. This was done to assess the impact on positron emission tomography (PET) range verification in proton therapy. A DECT-based brain tissue segmentation method was developed for white matter (WM), grey matter (GM) and cerebrospinal fluid (CSF). The elemental composition of reference tissues was assigned to closest CT numbers in DECT space (DECTdist). The method was also applied to SECT data (SECTdist). In a validation experiment, the proton irradiation induced PET activity of three brain equivalent solutions (BES) was compared to simulations based on different tissue segmentations. Five patients scanned with a dual source DECT scanner were analyzed to compare the different segmentation methods. A single magnetic resonance (MR) scan was used for comparison with an established segmentation toolkit. Additionally, one patient with SECT and post-treatment PET scans was investigated. For BES, DECTdist and SECTdist reduced differences to the reference simulation by up to 62% when compared to the conventional stoichiometric segmentation (SECTSchneider). In comparison to MR brain segmentation, Dice similarity coefficients for WM, GM and CSF were 0.61, 0.67 and 0.66 for DECTdist and 0.54, 0.41 and 0.66 for SECTdist. MC simulations of PET treatment verification in patients showed important differences between DECTdist/SECTdist and SECTSchneider for patients with large CSF areas within the treatment field but not in WM and GM. Differences could be misinterpreted as PET derived range shifts of up to 4 mm. DECTdist and SECTdist yielded comparable activity distributions, and comparison of SECTdist to a measured patient PET scan showed improved agreement when compared to SECTSchneider. The agreement between predicted and measured PET

  12. Advances in targeting the vacuolar proton-translocating ATPase (V-ATPase) for anti-fungal therapy

    Science.gov (United States)

    Hayek, Summer R.; Lee, Samuel A.; Parra, Karlett J.

    2014-01-01

    Vacuolar proton-translocating ATPase (V-ATPase) is a membrane-bound, multi-subunit enzyme that uses the energy of ATP hydrolysis to pump protons across membranes. V-ATPase activity is critical for pH homeostasis and organelle acidification as well as for generation of the membrane potential that drives secondary transporters and cellular metabolism. V-ATPase is highly conserved across species and is best characterized in the model fungus Saccharomyces cerevisiae. However, recent studies in mammals have identified significant alterations from fungi, particularly in the isoform composition of the 14 subunits and in the regulation of complex disassembly. These differences could be exploited for selectivity between fungi and humans and highlight the potential for V-ATPase as an anti-fungal drug target. Candida albicans is a major human fungal pathogen and causes fatality in 35% of systemic infections, even with anti-fungal treatment. The pathogenicity of C. albicans correlates with environmental, vacuolar, and cytoplasmic pH regulation, and V-ATPase appears to play a fundamental role in each of these processes. Genetic loss of V-ATPase in pathogenic fungi leads to defective virulence, and a comprehensive picture of the mechanisms involved is emerging. Recent studies have explored the practical utility of V-ATPase as an anti-fungal drug target in C. albicans, including pharmacological inhibition, azole therapy, and targeting of downstream pathways. This overview will discuss these studies as well as hypothetical ways to target V-ATPase and novel high-throughput methods for use in future drug discovery screens. PMID:24478704

  13. Advances in targeting the vacuolar proton-translocating ATPase (V-ATPase for anti-fungal therapy

    Directory of Open Access Journals (Sweden)

    Summer R. Hayek

    2014-01-01

    Full Text Available Vacuolar proton-translocating ATPase (V-ATPase is a membrane-bound, multi-subunit enzyme that uses the energy of ATP hydrolysis to pump protons across membranes. V-ATPase activity is critical for pH homeostasis and organelle acidification as well as for generation of the membrane potential that drives secondary transporters and cellular metabolism. V-ATPase is highly conserved across species and is best characterized in the model fungus Saccharomyces cerevisiae (S. cerevisiae. However, recent studies in mammals have identified significant alterations from fungi, particularly in the isoform composition of the 14 subunits and in the regulation of complex disassembly. These differences could be exploited for selectivity between fungi and humans and highlight the potential for V-ATPase as an anti-fungal drug target. Candida albicans (C. albicans is a major human fungal pathogen and causes fatality in 35% of systemic infections, even with anti-fungal treatment. The pathogenicity of C. albicans correlates with environmental, vacuolar, and cytoplasmic pH regulation, and V-ATPase appears to play a fundamental role in each of these processes. Genetic loss of V-ATPase in pathogenic fungi leads to defective virulence, and a comprehensive picture of the mechanisms involved is emerging. Recent studies have explored the practical utility of V-ATPase as an anti-fungal drug target in C. albicans, including pharmacological inhibition, azole therapy, and targeting of downstream pathways. This overview will discuss these studies as well as hypothetical ways to target V-ATPase and novel high-throughput methods for use in future drug discovery screens.

  14. SU-E-T-391: Evaluation of Image Parameters Impact On the CT Calibration Curve for Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Z; Reyhan, M; Huang, Q; Zhang, M; Yue, N; Chen, T [Rutgers University, New Brunswick, NJ (United States)

    2015-06-15

    Purpose: The calibration of the Hounsfield units (HU) to relative proton stopping powers (RSP) is a crucial component in assuring the accurate delivery of proton therapy dose distributions to patients. The purpose of this work is to assess the uncertainty of CT calibration considering the impact of CT slice thickness, position of the plug within the phantom and phantom sizes. Methods: Stoichiometric calibration method was employed to develop the CT calibration curve. Gammex 467 tissue characterization phantom was scanned in Tomotherapy Cheese phantom and Gammex 451 phantom by using a GE CT scanner. Each plug was individually inserted into the same position of inner and outer ring of phantoms at each time, respectively. 1.25 mm and 2.5 mm slice thickness were used. Other parameters were same. Results: HU of selected human tissues were calculated based on fitted coefficient (Kph, Kcoh and KKN), and RSP were calculated according to the Bethe-Bloch equation. The calibration curve was obtained by fitting cheese phantom data with 1.25 mm thickness. There is no significant difference if the slice thickness, phantom size, position of plug changed in soft tissue. For boney structure, RSP increases up to 1% if the phantom size and the position of plug changed but keep the slice thickness the same. However, if the slice thickness varied from the one in the calibration curve, 0.5%–3% deviation would be expected depending on the plug position. The Inner position shows the obvious deviation (averagely about 2.5%). Conclusion: RSP shows a clinical insignificant deviation in soft tissue region. Special attention may be required when using a different slice thickness from the calibration curve for boney structure. It is clinically practical to address 3% deviation due to different thickness in the definition of clinical margins.

  15. Outcomes in men with large prostates ({>=}60 cm{sup 3}) treated with definitive proton therapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Mcgee, Lisa; Mendenhall, William M. [Dept. of Radiation Oncology, Univ. of Florida Coll. of Medicine, Gainesville (United States); Mendenhall, Nancy P.; Morris, Christopher G.; Marcus, Robert J. Jr. [Dept. of Radiation Oncology, Univ. of Florida Coll. of Medicine, Gainesville (United States); Univ. of Florida Proton Therapy Inst., Jacksonville (United States); Henderson, Randal H.; Nichols, Romaine C. Jr.; Li, Zuofeng; Williams, Christopher R.; Hoppe, Bradford S. [Univ. of Florida Proton Therapy Inst., Jacksonville (United States)], e-mail: bhoppe@floridaproton.org

    2013-04-15

    Background: Large prostate size is associated with higher rates of genitourinary and gastrointestinal toxicities after definitive treatment for prostate cancer, and because of this many men will undergo cytoreduction with androgen deprivation therapy (ADT) before definitive therapy, which results in its own unique toxicities and worsens quality of life. This series investigates genitourinary and gastrointestinal toxicity in men with large prostates (> 60 cm{sup 3}) undergoing definitive proton therapy (PT) for prostate cancer. Material and methods: From 2006 to 2010, 186 men with prostates {>=}60 cm{sup 3} were treated with definitive PT (median dose, 78 CGE) for low- (47%), intermediate- (37%) and high-risk (16%) prostate cancer. Med