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Sample records for intensity modulated therapy

  1. Intensity-modulated radiation therapy.

    Science.gov (United States)

    Goffman, Thomas E; Glatstein, Eli

    2002-07-01

    Intensity-modulated radiation therapy (IMRT) is an increasingly popular technical means of tightly focusing the radiation dose around a cancer. As with stereotactic radiotherapy, IMRT uses multiple fields and angles to converge on the target. The potential for total dose escalation and for escalation of daily fraction size to the gross cancer is exciting. The excitement, however, has greatly overshadowed a range of radiobiological and clinical concerns.

  2. Fan beam intensity modulated proton therapy

    Science.gov (United States)

    Hill, Patrick M.

    A fan beam proton therapy is developed which delivers intensity modulated proton therapy using distal edge tracking. The system may be retrofit onto existing proton therapy gantries without alterations to infrastructure in order to improve treatments through intensity modulation. A novel range and intensity modulation system is designed using acrylic leaves that are inserted or retracted from subsections of the fan beam. Leaf thicknesses are chosen in a base-2 system and motivated in a binary manner. Dose spots from individual beam channels range between 1 and 5 cm. Integrated collimators attempting to limit crosstalk among beam channels are investigated, but found to be inferior to uncollimated beam channel modulators. A treatment planning system performing data manipulation in MATLAB and dose calculation in MCNPX is developed. Beamlet dose is calculated on patient CT data and a fan beam source is manually defined to produce accurate results. An energy deposition tally follows the CT grid, allowing straightforward registration of dose and image data. Simulations of beam channels assume that a beam channel either delivers dose to a distal edge spot or is intensity modulated. A final calculation is performed separately to determine the deliverable dose accounting for all sources of scatter. Treatment plans investigate the effects that varying system parameters have on dose distributions. Beam channel apertures may be as large as 20 mm because the sharp distal falloff characteristic of proton dose provides sufficient intensity modulation to meet dose objectives, even in the presence of coarse lateral resolution. Dose conformity suffers only when treatments are delivered from less than 10 angles. Jaw widths of 1--2 cm produce comparable dose distributions, but a jaw width of 4 cm produces unacceptable target coverage when maintaining critical structure avoidance. Treatment time for a prostate delivery is estimated to be on the order of 10 minutes. Neutron production

  3. Intensity-modulated arc therapy simplified

    International Nuclear Information System (INIS)

    Wong, Eugene; Chen, Jeff Z.; Greenland, Jonathan

    2002-01-01

    Purpose: We present a treatment planning strategy for intensity-modulated radiation therapy using gantry arcs with dynamic multileaf collimator, previously termed intensity-modulated arc therapy (IMAT). Methods and Materials: The planning strategy is an extension of the photon bar arc and asymmetric arc techniques and is classified into three levels of complexity, with increasing number of gantry arcs. This principle allows us to generalize the analysis of the number of arcs required for intensity modulation for a given treatment site. Using a phantom, we illustrate how the current technique is more flexible than the photon bar arc technique. We then compare plans from our strategy with conventional three-dimensional conformal treatment plans for three sites: prostate (prostate plus seminal vesicles), posterior pharyngeal wall, and chest wall. Results: Our strategy generates superior IMAT treatment plans compared to conventional three-dimensional conformal plans. The IMAT plans spare critical organs well, and the trade-off for simplicity is that the dose uniformity in the target volume may not rival that of true inverse treatment plans. Conclusions: The analyses presented in this paper give a better understanding of IMAT plans. Our strategy is easier to understand and more efficient in generating plans than inverse planning systems; our plans are also simpler to modify, and quality assurance is more intuitive

  4. Fan-beam intensity modulated proton therapy.

    Science.gov (United States)

    Hill, Patrick; Westerly, David; Mackie, Thomas

    2013-11-01

    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. 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. 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. Overall, the sharp distal

  5. Inverse planning of intensity modulated proton therapy

    International Nuclear Information System (INIS)

    Nill, S.; Oelfke, U.; Bortfeld, T.

    2004-01-01

    A common requirement of radiation therapy is that treatment planning for different radiation modalities is devised on the basis of the same treatment planning system (TPS). The present study presents a novel multi-modal TPS with separate modules for the dose calculation, the optimization engine and the graphical user interface, which allows to integrate different treatment modalities. For heavy-charged particles, both most promising techniques, the distal edge tracking (DET) and the 3-dimensional scanning (3D) technique can be optimized. As a first application, the quality of optimized intensity-modulated treatment plans for photons (IMXT) and protons (IMPT) was analyzed in one clinical case on the basis of the achieved physical dose distributions. A comparison of the proton plans with the photon plans showed no significant improvement in terms of target volume dose, however there was an improvement in terms of organs at risk as well as a clear reduction of the total integral dose. For the DET technique, it is possible to create a treatment plan with almost the same quality of the 3D technique, however with a clearly reduced number (factor of 5) of beam spots as well as a reduced optimization time. Due to its modular design, the system can be easily expanded to more sophisticated dose-calculation algorithms or to modeling of biological effects. (orig.) [de

  6. Single-energy intensity modulated proton therapy

    Science.gov (United States)

    Farace, Paolo; Righetto, Roberto; Cianchetti, Marco

    2015-09-01

    In this note, an intensity modulated proton therapy (IMPT) technique, based on the use of high single-energy (SE-IMPT) pencil beams, is described. The method uses only the highest system energy (226 MeV) and only lateral penumbra to produce dose gradient, as in photon therapy. In the study, after a preliminary analysis of the width of proton pencil beam penumbras at different depths, SE-IMPT was compared with conventional IMPT in a phantom containing titanium inserts and in a patient, affected by a spinal chordoma with fixation rods. It was shown that SE-IMPT has the potential to produce a sharp dose gradient and that it is not affected by the uncertainties produced by metal implants crossed by the proton beams. Moreover, in the chordoma patient, target coverage and organ at risk sparing of the SE-IMPT plan resulted comparable to that of the less reliable conventional IMPT technique. Robustness analysis confirmed that SE-IMPT was not affected by range errors, which can drastically affect the IMPT plan. When accepting a low-dose spread as in modern photon techniques, SE-IMPT could be an option for the treatment of lesions (e.g. cervical bone tumours) where steep dose gradient could improve curability, and where range uncertainty, due for example to the presence of metal implants, hampers conventional IMPT.

  7. Single-energy intensity modulated proton therapy.

    Science.gov (United States)

    Farace, Paolo; Righetto, Roberto; Cianchetti, Marco

    2015-10-07

    In this note, an intensity modulated proton therapy (IMPT) technique, based on the use of high single-energy (SE-IMPT) pencil beams, is described.The method uses only the highest system energy (226 MeV) and only lateral penumbra to produce dose gradient, as in photon therapy. In the study, after a preliminary analysis of the width of proton pencil beam penumbras at different depths, SE-IMPT was compared with conventional IMPT in a phantom containing titanium inserts and in a patient, affected by a spinal chordoma with fixation rods.It was shown that SE-IMPT has the potential to produce a sharp dose gradient and that it is not affected by the uncertainties produced by metal implants crossed by the proton beams. Moreover, in the chordoma patient, target coverage and organ at risk sparing of the SE-IMPT plan resulted comparable to that of the less reliable conventional IMPT technique. Robustness analysis confirmed that SE-IMPT was not affected by range errors, which can drastically affect the IMPT plan.When accepting a low-dose spread as in modern photon techniques, SE-IMPT could be an option for the treatment of lesions (e.g. cervical bone tumours) where steep dose gradient could improve curability, and where range uncertainty, due for example to the presence of metal implants, hampers conventional IMPT.

  8. Single-energy intensity modulated proton therapy

    International Nuclear Information System (INIS)

    Farace, Paolo; Righetto, Roberto; Cianchetti, Marco

    2015-01-01

    In this note, an intensity modulated proton therapy (IMPT) technique, based on the use of high single-energy (SE-IMPT) pencil beams, is described.The method uses only the highest system energy (226 MeV) and only lateral penumbra to produce dose gradient, as in photon therapy. In the study, after a preliminary analysis of the width of proton pencil beam penumbras at different depths, SE-IMPT was compared with conventional IMPT in a phantom containing titanium inserts and in a patient, affected by a spinal chordoma with fixation rods.It was shown that SE-IMPT has the potential to produce a sharp dose gradient and that it is not affected by the uncertainties produced by metal implants crossed by the proton beams. Moreover, in the chordoma patient, target coverage and organ at risk sparing of the SE-IMPT plan resulted comparable to that of the less reliable conventional IMPT technique. Robustness analysis confirmed that SE-IMPT was not affected by range errors, which can drastically affect the IMPT plan.When accepting a low-dose spread as in modern photon techniques, SE-IMPT could be an option for the treatment of lesions (e.g. cervical bone tumours) where steep dose gradient could improve curability, and where range uncertainty, due for example to the presence of metal implants, hampers conventional IMPT. (note)

  9. Film Dosimetry for Intensity Modulated Radiation Therapy

    International Nuclear Information System (INIS)

    Benites-Rengifo, J.; Martinez-Davalos, A.; Celis, M.; Larraga, J.

    2004-01-01

    Intensity Modulated Radiation Therapy (IMRT) is an oncology treatment technique that employs non-uniform beam intensities to deliver highly conformal radiation to the targets while minimizing doses to normal tissues and critical organs. A key element for a successful clinical implementation of IMRT is establishing a dosimetric verification process that can ensure that delivered doses are consistent with calculated ones for each patient. To this end we are developing a fast quality control procedure, based on film dosimetry techniques, to be applied to the 6 MV Novalis linear accelerator for IMRT of the Instituto Nacional de Neurologia y Neurocirugia (INNN) in Mexico City. The procedure includes measurements of individual fluence maps for a limited number of fields and dose distributions in 3D using extended dose-range radiographic film. However, the film response to radiation might depend on depth, energy and field size, and therefore compromise the accuracy of measurements. In this work we present a study of the dependence of Kodak EDR2 film's response on the depth, field size and energy, compared with those of Kodak XV2 film. The first aim is to devise a fast and accurate method to determine the calibration curve of film (optical density vs. doses) commonly called a sensitometric curve. This was accomplished by using three types of irradiation techniques: Step-and-shoot, dynamic and static fields

  10. Intensity-Modulated Radiation Therapy (IMRT)

    Science.gov (United States)

    ... type your comment or suggestion into the following text box: Comment: E-mail: Area code: Phone no: Thank ... Accelerator Prostate Cancer Treatment Head and Neck Cancer Treatment Introduction to Cancer Therapy (Radiation Oncology) ...

  11. The pitfalls of dosimetric commissioning for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Tohyama, Naoki; Kodama, Takashi; Hatano, K.

    2013-01-01

    Intensity modulated radiation therapy (IMRT) allows higher radiation dose to be focused to the target volumes while minimizing the dose to OAR. To start of clinical treatment in IMRTvwe must perform commissioning strictly than 3D-conformal radiotherapy (CRT). In this report, pitfalls of dosimetric commissioning for intensity modulated radiation therapy were reviewed. Multileaf collimator (MLC) offsets and MLC transmissions are important parameters in commissioning of RTPS for IMRT. Correction of depth scaling and fluence scaling is necessary for dose measurement using solid phantom. (author)

  12. Potential clinical efficacy of intensity-modulated conformal therapy

    International Nuclear Information System (INIS)

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

    1998-01-01

    Purpose: The purpose of this study was to examine the potential benefit of using intensity-modulated conformal therapy for a variety of lesions currently treated with stereotactic radiosurgery or conventional radiotherapy. Methods and Materials: Intensity-modulated conformal treatment plans were generated for small intracranial lesions, as well as head and neck, lung, breast, and prostate cases, using the Peacock Plan[reg] treatment-planning system (Nomos Corporation). For small intracranial lesions, intensity-modulated conformal treatment plans were compared with stereotactic radiosurgery treatment plans generated for patient treatment at the University of Florida Shands Cancer Center. For other sites (head and neck, lung, breast, and prostate), plans generated using the Peacock Plan[reg] were compared with conventional treatment plans, as well as beam's-eye-view conformal treatment plans. Plan comparisons were accomplished through conventional qualitative review of two-dimensional (2D) dose distributions in conjunction with quantitative techniques, such as dose-volume histograms, dosimetric statistics, normal tissue complication probabilities, tumor control probabilities, and objective numerical scoring. Results: For small intracranial lesions, there is little difference between intensity-modulated conformal treatment planning and radiosurgery treatment planning in the conformation of high isodose lines with the target volume. However, stereotactic treatment planning provides a steeper dose gradient outside the target volume and, hence, a lower normal tissue toxicity index. For extracranial sites, objective numerical scores for beam's-eye-view and intensity-modulated conformal planning techniques are superior to scores for conventional treatment plans. The beam's-eye-view planning technique prevents geographic target misses and better excludes healthy tissues from the treatment portal. Compared with scores for the beam's-eye-view planning technique, scores for

  13. Intensity-modulated radiation therapy: first reported treatment in Australasia

    International Nuclear Information System (INIS)

    Corry, J.; Joon, D.L.; Hope, G.; Smylie, J.; Henkul, Z.; Wills, J.; Cramb, J.; Towns, S.; Archer, P.

    2002-01-01

    Intensity-modulated radiation therapy (IMRT) is an exciting new advance in the practice of radiation oncology. It is the use of non-uniform radiation beams to achieve conformal dose distributions. As a result of the high initial capital costs and the time and complexity of planning, IMRT is not yet a widely available clinical treatment option. We describe the process involved in applying this new technology to a case of locally advanced nasopharyngeal cancer. Copyright (2002) Blackwell Science Pty Ltd

  14. Energy and intensity modulated radiation therapy with electrons

    OpenAIRE

    Olofsson, Lennart

    2005-01-01

    In recent years intensity modulated radiation therapy with photons (xIMRT) has gained attention due to its ability to reduce the dose in the tissues close to the tumour volume. However, this technique also results in a large low dose volume. Electron IMRT (eIMRT) has the potential to reduce the integral dose to the patient due to the dose fall off in the electron depth dose curves. This dose fall off makes it possible to modulate the dose distribution in the direction of the beam by selecting...

  15. A proton beam delivery system for conformal therapy and intensity modulated therapy

    International Nuclear Information System (INIS)

    Yu Qingchang

    2001-01-01

    A scattering proton beam delivery system for conformal therapy and intensity modulated therapy is described. The beam is laterally spread out by a dual-ring double scattering system and collimated by a program-controlled multileaf collimator and patient specific fixed collimators. The proton range is adjusted and modulated by a program controlled binary filter and ridge filters

  16. Linear algebraic methods applied to intensity modulated radiation therapy.

    Science.gov (United States)

    Crooks, S M; Xing, L

    2001-10-01

    Methods of linear algebra are applied to the choice of beam weights for intensity modulated radiation therapy (IMRT). It is shown that the physical interpretation of the beam weights, target homogeneity and ratios of deposited energy can be given in terms of matrix equations and quadratic forms. The methodology of fitting using linear algebra as applied to IMRT is examined. Results are compared with IMRT plans that had been prepared using a commercially available IMRT treatment planning system and previously delivered to cancer patients.

  17. Intensity-modulated radiation therapy clinical evidence and techniques

    CERN Document Server

    Nishimura, Yasumasa

    2015-01-01

    Successful clinical use of intensity-modulated radiation therapy (IMRT) represents a significant advance in radiation oncology. Because IMRT can deliver high-dose radiation to a target with a reduced dose to the surrounding organs, it can improve the local control rate and reduce toxicities associated with radiation therapy. Since IMRT began being used in the mid-1990s, a large volume of clinical evidence of the advantages of IMRT has been collected. However, treatment planning and quality assurance (QA) of IMRT are complicated and difficult for the clinician and the medical physicist. This book, by authors renowned for their expertise in their fields, provides cumulative clinical evidence and appropriate techniques for IMRT for the clinician and the physicist. Part I deals with the foundations and techniques, history, principles, QA, treatment planning, radiobiology and related aspects of IMRT. Part II covers clinical applications with several case studies, describing contouring and dose distribution with cl...

  18. Intensity-Modulated Radiation Therapy for Primary Brain Tumors

    Institute of Scientific and Technical Information of China (English)

    Zhong-min Wang

    2004-01-01

    Radiation therapy has been used to treat primary brain tumors as standard primary and/or adjunctive therapies for decades. It is difficult for conventional radiotherapy to deliver a lethal dose of radiation to the tumors while sparing surrounding normal brain due to complicated structures and multifunction in human brain. With the understanding of radiation physics and computer technology, a number of novel and more precise radiotherapies have been developed in recent years. Intensity modulated radiotherapy (IMRT) is one of these strategies. The use of IMRT in the treatment of primary brain tumors is being increasing nowadays. It shows great promise for some of primary brain tumors and also presents some problems, This review highlights current IMRT in the treatment of mainly primary brain tumors.

  19. Quality assurance of intensity-modulated radiation therapy.

    Science.gov (United States)

    Palta, Jatinder R; Liu, Chihray; Li, Jonathan G

    2008-01-01

    The current paradigm for the quality assurance (QA) program for intensity-modulated radiation therapy (IMRT) includes QA of the treatment planning system, QA of the delivery system, and patient-specific QA. Although the IMRT treatment planning and delivery system is the same as for conventional three-dimensional conformal radiation therapy, it has more parameters to coordinate and verify. Because of complex beam intensity modulation, each IMRT field often includes many small irregular off-axis fields, resulting in isodose distributions for each IMRT plan that are more conformal than those from conventional treatment plans. Therefore, these features impose a new and more stringent set of QA requirements for IMRT planning and delivery. The generic test procedures to validate dose calculation and delivery accuracy for both treatment planning and IMRT delivery have to be customized for each type of IMRT planning and delivery strategy. The rationale for such an approach is that the overall accuracy of IMRT delivery is incumbent on the piecewise uncertainties in both the planning and delivery processes. The end user must have well-defined evaluation criteria for each element of the planning and delivery process. Such information can potentially be used to determine a priori the accuracy of IMRT planning and delivery.

  20. Quality Assurance of Intensity-Modulated Radiation Therapy

    International Nuclear Information System (INIS)

    Palta, Jatinder R.; Liu, Chihray; Li, Jonathan G.

    2008-01-01

    The current paradigm for the quality assurance (QA) program for intensity-modulated radiation therapy (IMRT) includes QA of the treatment planning system, QA of the delivery system, and patient-specific QA. Although the IMRT treatment planning and delivery system is the same as for conventional three-dimensional conformal radiation therapy, it has more parameters to coordinate and verify. Because of complex beam intensity modulation, each IMRT field often includes many small irregular off-axis fields, resulting in isodose distributions for each IMRT plan that are more conformal than those from conventional treatment plans. Therefore, these features impose a new and more stringent set of QA requirements for IMRT planning and delivery. The generic test procedures to validate dose calculation and delivery accuracy for both treatment planning and IMRT delivery have to be customized for each type of IMRT planning and delivery strategy. The rationale for such an approach is that the overall accuracy of IMRT delivery is incumbent on the piecewise uncertainties in both the planning and delivery processes. The end user must have well-defined evaluation criteria for each element of the planning and delivery process. Such information can potentially be used to determine a priori the accuracy of IMRT planning and delivery

  1. Prone Breast Intensity Modulated Radiation Therapy: 5-Year Results

    International Nuclear Information System (INIS)

    Osa, Etin-Osa O.; DeWyngaert, Keith; Roses, Daniel; Speyer, James; Guth, Amber; Axelrod, Deborah; Fenton Kerimian, Maria; Goldberg, Judith D.; Formenti, Silvia C.

    2014-01-01

    Purpose: To report the 5-year results of a technique of prone breast radiation therapy delivered by a regimen of accelerated intensity modulated radiation therapy with a concurrent boost to the tumor bed. Methods and Materials: Between 2003 and 2006, 404 patients with stage I-II breast cancer were prospectively enrolled into 2 consecutive protocols, institutional trials 03-30 and 05-181, that used the same regimen of 40.5 Gy/15 fractions delivered to the index breast over 3 weeks, with a concomitant daily boost to the tumor bed of 0.5 Gy (total dose 48 Gy). All patients were treated after segmental mastectomy and had negative margins and nodal assessment. Patients were set up prone: only if lung or heart volumes were in the field was a supine setup attempted and chosen if found to better spare these organs. Results: Ninety-two percent of patients were treated prone, 8% supine. Seventy-two percent had stage I, 28% stage II invasive breast cancer. In-field lung volume ranged from 0 to 228.27 cm 3 , mean 19.65 cm 3 . In-field heart volume for left breast cancer patients ranged from 0 to 21.24 cm 3 , mean 1.59 cm 3 . There was no heart in the field for right breast cancer patients. At a median follow-up of 5 years, the 5-year cumulative incidence of isolated ipsilateral breast tumor recurrence was 0.82% (95% confidence interval [CI] 0.65%-1.04%). The 5-year cumulative incidence of regional recurrence was 0.53% (95% CI 0.41%-0.69%), and the 5-year overall cumulative death rate was 1.28% (95% CI 0.48%-3.38%). Eighty-two percent (95% CI 77%-85%) of patients judged their final cosmetic result as excellent/good. Conclusions: Prone accelerated intensity modulated radiation therapy with a concomitant boost results in excellent local control and optimal sparing of heart and lung, with good cosmesis. Radiation Therapy Oncology Group protocol 1005, a phase 3, multi-institutional, randomized trial is ongoing and is evaluating the equivalence of a similar dose and fractionation

  2. Prone Breast Intensity Modulated Radiation Therapy: 5-Year Results

    Energy Technology Data Exchange (ETDEWEB)

    Osa, Etin-Osa O.; DeWyngaert, Keith [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States); Roses, Daniel [Department of Surgery, New York University School of Medicine, New York, New York (United States); Speyer, James [Department of Medical Oncology, New York University School of Medicine, New York, New York (United States); Guth, Amber; Axelrod, Deborah [Department of Surgery, New York University School of Medicine, New York, New York (United States); Fenton Kerimian, Maria [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States); Goldberg, Judith D. [Department of Population Health, New York University School of Medicine, New York, New York (United States); Formenti, Silvia C., E-mail: Silvia.formenti@nyumc.org [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States)

    2014-07-15

    Purpose: To report the 5-year results of a technique of prone breast radiation therapy delivered by a regimen of accelerated intensity modulated radiation therapy with a concurrent boost to the tumor bed. Methods and Materials: Between 2003 and 2006, 404 patients with stage I-II breast cancer were prospectively enrolled into 2 consecutive protocols, institutional trials 03-30 and 05-181, that used the same regimen of 40.5 Gy/15 fractions delivered to the index breast over 3 weeks, with a concomitant daily boost to the tumor bed of 0.5 Gy (total dose 48 Gy). All patients were treated after segmental mastectomy and had negative margins and nodal assessment. Patients were set up prone: only if lung or heart volumes were in the field was a supine setup attempted and chosen if found to better spare these organs. Results: Ninety-two percent of patients were treated prone, 8% supine. Seventy-two percent had stage I, 28% stage II invasive breast cancer. In-field lung volume ranged from 0 to 228.27 cm{sup 3}, mean 19.65 cm{sup 3}. In-field heart volume for left breast cancer patients ranged from 0 to 21.24 cm{sup 3}, mean 1.59 cm{sup 3}. There was no heart in the field for right breast cancer patients. At a median follow-up of 5 years, the 5-year cumulative incidence of isolated ipsilateral breast tumor recurrence was 0.82% (95% confidence interval [CI] 0.65%-1.04%). The 5-year cumulative incidence of regional recurrence was 0.53% (95% CI 0.41%-0.69%), and the 5-year overall cumulative death rate was 1.28% (95% CI 0.48%-3.38%). Eighty-two percent (95% CI 77%-85%) of patients judged their final cosmetic result as excellent/good. Conclusions: Prone accelerated intensity modulated radiation therapy with a concomitant boost results in excellent local control and optimal sparing of heart and lung, with good cosmesis. Radiation Therapy Oncology Group protocol 1005, a phase 3, multi-institutional, randomized trial is ongoing and is evaluating the equivalence of a similar dose and

  3. Clinical implementation and quality assurance for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Ma, C.-M.; Price, R.; McNeeley, S.; Chen, L.; Li, J.S.; Wang, L.; Ding, M.; Fourkal, E.; Qin, L.

    2002-01-01

    This paper describes the clinical implementation and quality assurance (QA) for intensity-modulated radiation therapy (IMRT) based on the experience at Fox Chase Cancer Center, Philadelphia, USA. We will review our procedures for the clinical implementation of the IMRT technique and the requirements for patient immobilization, target delineation, treatment optimization, beam delivery and system administration. We will discuss the dosimetric requirements and measurement procedures for beam commissioning and dosimetry verification for IMRT. We will examine the details of model-based dose calculation for IMRT treatment planning and the potential problems with such dose calculation algorithms. We will discuss the effect of beam delivery systems on the actual dose distributions received by the patients and the methods to incorporate such effects in the treatment optimization process. We will investigate the use of the Monte Carlo method for dose calculation and treatment verification for IMRT

  4. Current status of intensity-modulated radiation therapy (IMRT)

    International Nuclear Information System (INIS)

    Hatano, Kazuo; Araki, Hitoshi; Sakai, Mitsuhiro

    2007-01-01

    External-beam radiation therapy has been one of the treatment options for prostate cancer. The dose response has been observed for a dose range of 64.8-81 Gy. The problem of external-beam radiotherapy (RT) for prostate cancer is that as the dose increases, adverse effects also increase. Three-dimensional conformal radiation therapy (3D-CRT) has enabled us to treat patients with up to 72-76 Gy to the prostate, with a relatively acceptable risk of late rectal bleeding. Recently, intensity-modulated radiation therapy (IMRT) has been shown to deliver a higher dose to the target with acceptable low rates of rectal and bladder complications. The most important things to keep in mind when using an IMRT technique are that there is a significant trade-off between coverage of the target, avoidance of adjacent critical structures, and the inhomogeneity of the dose within the target. Lastly, even with IMRT, it should be kept in mind that a ''perfect'' plan that creates completely homogeneous coverage of the target volume and zero or small dose to the adjacent organs at risk is not always obtained. Participating in many treatment planning sessions and arranging the beams and beam weights create the best approach to the best IMRT plan. (author)

  5. Intensity Modulated Radiation Therapy. Development of the technique

    International Nuclear Information System (INIS)

    Rafailovici, L.; Alva, R.; Chiozza, J.; Donato, H.; Falomo, S.; Cardiello, C.; Furia, O.; Martinez, A.; Filomia, M.L.; Sansogne, R.; Arbiser, S.; Dosoretz, B.

    2008-01-01

    Full text: Introduction: Intensity Modulated Radiation Therapy (IMRT) is a result of advances in computer sciences that allowed the development of new technology related to planning and radiation therapy. IMRT was developed to homogenize the dose in the target volumes and decrease the dose in the surrounding healthy tissue. Using a software with high calculation capacity a simultaneous irradiation with different doses in a given volume is achieved. IMRT is based on internal planning. Material and methods: 628 patients were treated with IMRT in prostate lesions, head and neck, breast, thorax, abdomen and brain since August 2008. The software for IMRT is the XIO CMS and the accelerator used is a Varian Clinac 6 / 100. IMRT requires a first simulation, where immobilization systems are selected (mats, thermoplastic masks, among others) and the demarcation of the target structures, healthy tissue and dose prescription by a tattoo. Images of CT / MRI are merged when necessary. Once the system made the treatment optimization, this one is regulated by modulators. These are produced by numerical control machines from digital files produced by software. In a second modulation the planned irradiation is checked and tattoo is carried out according with this. We have a strict process of quality assurance to assess the viability of the plan before its implementation. We use the Map Check it possible to compare the dose on the central axis and the distribution in the whole plane regarding to that generated by the planning system. From 03/2008 the virtual simulation process was implemented integrating the described stages. Results and Conclusions: IMRT is a complex technique. The meticulous planning, implementation of process and quality control allows the use of this technique in a reliable and secure way. With IMRT we achieved a high level of dose conformation, less irradiation of healthy tissue, lower rates of complications and the dose escalation for some tumors. (authors) [es

  6. Intensity-modulated radiation therapy: dynamic MLC (DMLC) therapy, multisegment therapy and tomotherapy. An example of QA in DMLC therapy

    International Nuclear Information System (INIS)

    Webb, S.

    1998-01-01

    Intensity-modulated radiation therapy will make a quantum leap in tumor control. It is the new radiation therapy for the new millennium. The major methods to achieve IMRT are: 1. Dynamic multileaf collimator (DMLC) therapy, 2. multisegment therapy, and 3. tomotherapy. The principles of these 3 techniques are briefly reviewed. Each technique presents unique QA issues which are outlined. As an example this paper will present the results of a recent new study of an important QA concern in DMLC therapy. (orig.) [de

  7. Dosimetric verification of the intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Zou Huawei; Jia Mingxuan; Wu Rong; Xiao Fuda; Dong Xiaoqi

    2004-01-01

    Objective: To discuss the methods of the dosimetric verification in the intensity-modulated radiation therapy (IMRT) and insure correct execution of the IMRT planning in the clinical practice. Methods: The CMSFOCUS9200 inverse planning system was used to provide optimized 5-field IMRT treatment plans for the patients. A phantom was made from true water-equivalent material. The doses of the interesting points and isodose distributions of the interesting planes in the phantom were calculated using patients' treatment plan. The phantom was placed on the couch of the accelerator and was irradiated using the phantom's treatment planning data. The doses of interesting points were measured using a 0.23 cc chamber and the isodose distributions of interesting planes were measured using RIT 113 film dosimetry system in the phantom. The results were compared with those from calculation in planning system for verification. Results: The doses and isodose distributions measured by the chamber and the film were consistent with those predicted by the planning. The error between the measured dose and calculated dose in the interesting points was less than 3%. Conclusion: The dosimetric verification of IMRT is a reliable measure in the course of its implementation. (authors)

  8. Intensity-Modulated Radiation Therapy in Childhood Ependymoma

    International Nuclear Information System (INIS)

    Schroeder, Thomas M.; Chintagumpala, Murali; Okcu, M. Fatih; Chiu, J. Kam; Teh, Bin S.; Woo, Shiao Y.; Paulino, Arnold C.

    2008-01-01

    Purpose: To determine the patterns of failure after intensity-modulated radiation therapy (IMRT) for localized intracranial ependymoma. Methods and Materials: From 1994 to 2005, 22 children with pathologically proven, localized, intracranial ependymoma were treated with adjuvant IMRT. Of the patients, 12 (55%) had an infratentorial tumor and 14 (64%) had anaplastic histology. Five patients had a subtotal resection (STR), as evidenced by postoperative magnetic resonance imaging. The clinical target volume encompassed the tumor bed and any residual disease plus margin (median dose 54 Gy). Median follow-up for surviving patients was 39.8 months. Results: The 3-year overall survival rate was 87% ± 9%. The 3-year local control rate was 68% ± 12%. There were six local recurrences, all in the high-dose region of the treatment field. Median time to recurrence was 21.7 months. Of the 5 STR patients, 4 experienced recurrence and 3 died. Patients with a gross total resection had significantly better local control (p = 0.024) and overall survival (p = 0.008) than those with an STR. At last follow-up, no patient had developed visual loss, brain necrosis, myelitis, or a second malignancy. Conclusions: Treatment with IMRT provides local control and survival rates comparable with those in historic publications using larger treatment volumes. All failures were within the high-dose region, suggesting that IMRT does not diminish local control. The degree of surgical resection was shown to be significant for local control and survival

  9. Whole-brain hippocampal sparing radiation therapy: Volume-modulated arc therapy vs intensity-modulated radiation therapy case study

    International Nuclear Information System (INIS)

    Lee, Katrina; Lenards, Nishele; Holson, Janice

    2016-01-01

    The hippocampus is responsible for memory and cognitive function. An ongoing phase II clinical trial suggests that sparing dose to the hippocampus during whole-brain radiation therapy can help preserve a patient's neurocognitive function. Progressive research and advancements in treatment techniques have made treatment planning more sophisticated but beneficial for patients undergoing treatment. The aim of this study is to evaluate and compare hippocampal sparing whole-brain (HS-WB) radiation therapy treatment planning techniques using volume-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT). We randomly selected 3 patients to compare different treatment techniques that could be used for reducing dose to the hippocampal region. We created 2 treatment plans, a VMAT and an IMRT, from each patient's data set and planned on the Eclipse 11.0 treatment planning system (TPS). A total of 6 plans (3 IMRT and 3 VMAT) were created and evaluated for this case study. The physician contoured the hippocampus as per the Radiation Therapy Oncology Group (RTOG) 0933 protocol atlas. The organs at risk (OR) were contoured and evaluated for the plan comparison, which included the spinal cord, optic chiasm, the right and left eyes, lenses, and optic nerves. Both treatment plans produced adequate coverage on the planning target volume (PTV) while significantly reducing dose to the hippocampal region. The VMAT treatment plans produced a more homogenous dose distribution throughout the PTV while decreasing the maximum point dose to the target. However, both treatment techniques demonstrated hippocampal sparing when irradiating the whole brain.

  10. Ultrasound-based guidance of intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Fung, Albert Y.C.; Ayyangar, Komanduri M.; Djajaputra, David; Nehru, Ramasamy M.; Enke, Charles A.

    2006-01-01

    In ultrasound-guided intensity-modulated radiation therapy (IMRT) of prostate cancer, ultrasound imaging ascertains the anatomical position of patients during x-ray therapy delivery. The ultrasound transducers are made of piezoelectric ceramics. The same crystal is used for both ultrasound production and reception. Three-dimensional (3D) ultrasound devices capture and correlate series of 2-dimensional (2D) B-mode images. The transducers are often arranged in a convex array for focusing. Lower frequency reaches greater depth, but results in low resolution. For clear image, some gel is usually applied between the probe and the skin contact surface. For prostate positioning, axial and sagittal scans are performed, and the volume contours from computed tomography (CT) planning are superimposed on the ultrasound images obtained before radiation delivery at the linear accelerator. The planning volumes are then overlaid on the ultrasound images and adjusted until they match. The computer automatically deduces the offset necessary to move the patient so that the treatment area is in the correct location. The couch is translated as needed. The currently available commercial equipment can attain a positional accuracy of 1-2 mm. Commercial manufacturer designs differ in the detection of probe coordinates relative to the isocenter. Some use a position-sensing robotic arm, while others have infrared light-emitting diodes or pattern-recognition software with charge-couple-device cameras. Commissioning includes testing of image quality and positional accuracy. Ultrasound is mainly used in prostate positioning. Data for 7825 daily fractions of 234 prostate patients indicated average 3D inter-fractional displacement of about 7.8 mm. There was no perceivable trend of shift over time. Scatter plots showed slight prevalence toward superior-posterior directions. Uncertainties of ultrasound guidance included tissue inhomogeneities, speckle noise, probe pressure, and inter

  11. Iterative regularization in intensity-modulated radiation therapy optimization

    International Nuclear Information System (INIS)

    Carlsson, Fredrik; Forsgren, Anders

    2006-01-01

    A common way to solve intensity-modulated radiation therapy (IMRT) optimization problems is to use a beamlet-based approach. The approach is usually employed in a three-step manner: first a beamlet-weight optimization problem is solved, then the fluence profiles are converted into step-and-shoot segments, and finally postoptimization of the segment weights is performed. A drawback of beamlet-based approaches is that beamlet-weight optimization problems are ill-conditioned and have to be regularized in order to produce smooth fluence profiles that are suitable for conversion. The purpose of this paper is twofold: first, to explain the suitability of solving beamlet-based IMRT problems by a BFGS quasi-Newton sequential quadratic programming method with diagonal initial Hessian estimate, and second, to empirically show that beamlet-weight optimization problems should be solved in relatively few iterations when using this optimization method. The explanation of the suitability is based on viewing the optimization method as an iterative regularization method. In iterative regularization, the optimization problem is solved approximately by iterating long enough to obtain a solution close to the optimal one, but terminating before too much noise occurs. Iterative regularization requires an optimization method that initially proceeds in smooth directions and makes rapid initial progress. Solving ten beamlet-based IMRT problems with dose-volume objectives and bounds on the beamlet-weights, we find that the considered optimization method fulfills the requirements for performing iterative regularization. After segment-weight optimization, the treatments obtained using 35 beamlet-weight iterations outperform the treatments obtained using 100 beamlet-weight iterations, both in terms of objective value and of target uniformity. We conclude that iterating too long may in fact deteriorate the quality of the deliverable plan

  12. Quality assurance of patients for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Yoon, Sang Min; Yi, Byong Yong; Choi, Eun Kyung; Kim, Jong Hoon; Ahn, Seung Do; Lee, Sang Wook

    2002-01-01

    To establish and verify the proper and the practical IMRT (intensity-modulated radiation therapy) patient QA (Quality Assurance). An IMRT QA which consists of 3 steps and 16 items were designed and examined the validity of the program by applying to 9 patients, 12 IMRT cases of various sites. The three step QA program consists of RTP related QA, treatment information flow QA, and a treatment delivery QA procedure. The evaluation of organ constraints, the validity of the point dose, and the dose distribution are major issues in the RTP related QA procedure. The leaf sequence file generation, the evaluation of the MLC control file, the comparison of the dry run film, and the IMRT field simulate image were included in the treatment information flow procedure QA. The patient setup QA, the verification of the IMRT treatment fields to the patients, and the examination of the data in the Record and Verify system make up the treatment delivery QA procedure. The point dose measurement results of 10 cases showed good agreement with the RTP calculation within 3%. One case showed more than a 3% difference and the other case showed more than 5%, which was out side the tolerance level. We could not find any differences of more than 2 mm between the RTP leaf sequence and the dry run film. Film dosimetry and the dose distribution from the phantom plan showed the same tendency, but quantitative analysis was not possible because of the film dosimetry nature. No error had been found from the MLC control file and one mis-registration case was found before treatment. This study shows the usefulness and the necessity of the IMRT patient QA program. The whole procedure of this program should be performed, especially by institutions that have just started to accumulate experience. But, the program is too complex and time consuming. Therefore, we propose practical and essential QA items for institutions in which the IMRT is performed as a routine procedure

  13. Intensity Modulated Radiation Therapy With Dose Painting to Treat Rhabdomyosarcoma

    International Nuclear Information System (INIS)

    Yang, Joanna C.; Dharmarajan, Kavita V.; Wexler, Leonard H.; La Quaglia, Michael P.; Happersett, Laura; Wolden, Suzanne L.

    2012-01-01

    Purpose: To examine local control and patterns of failure in rhabdomyosarcoma patients treated with intensity modulated radiation therapy (RT) with dose painting (DP-IMRT). Patients and Methods: A total of 41 patients underwent DP-IMRT with chemotherapy for definitive treatment. Nineteen also underwent surgery with or without intraoperative RT. Fifty-six percent had alveolar histologic features. The median interval from beginning chemotherapy to RT was 17 weeks (range, 4-25). Very young children who underwent second-look procedures with or without intraoperative RT received reduced doses of 24-36 Gy in 1.4-1.8-Gy fractions. Young adults received 50.4 Gy to the primary tumor and lower doses of 36 Gy in 1.8-Gy fractions to at-risk lymph node chains. Results: With 22 months of median follow-up, the actuarial local control rate was 90%. Patients aged ≤7 years who received reduced overall and fractional doses had 100% local control, and young adults had 79% (P=.07) local control. Three local failures were identified in young adults whose primary target volumes had received 50.4 Gy in 1.8-Gy fractions. Conclusions: DP-IMRT with lower fractional and cumulative doses is feasible for very young children after second-look procedures with or without intraoperative RT. DP-IMRT is also feasible in adolescents and young adults with aggressive disease who would benefit from prophylactic RT to high-risk lymph node chains, although dose escalation might be warranted for improved local control. With limited follow-up, it appears that DP-IMRT produces local control rates comparable to those of sequential IMRT in patients with rhabdomyosarcoma.

  14. Linear energy transfer incorporated intensity modulated proton therapy optimization

    Science.gov (United States)

    Cao, Wenhua; Khabazian, Azin; Yepes, Pablo P.; Lim, Gino; Poenisch, Falk; Grosshans, David R.; Mohan, Radhe

    2018-01-01

    The purpose of this study was to investigate the feasibility of incorporating linear energy transfer (LET) into the optimization of intensity modulated proton therapy (IMPT) plans. Because increased LET correlates with increased biological effectiveness of protons, high LETs in target volumes and low LETs in critical structures and normal tissues are preferred in an IMPT plan. However, if not explicitly incorporated into the optimization criteria, different IMPT plans may yield similar physical dose distributions but greatly different LET, specifically dose-averaged LET, distributions. Conventionally, the IMPT optimization criteria (or cost function) only includes dose-based objectives in which the relative biological effectiveness (RBE) is assumed to have a constant value of 1.1. In this study, we added LET-based objectives for maximizing LET in target volumes and minimizing LET in critical structures and normal tissues. Due to the fractional programming nature of the resulting model, we used a variable reformulation approach so that the optimization process is computationally equivalent to conventional IMPT optimization. In this study, five brain tumor patients who had been treated with proton therapy at our institution were selected. Two plans were created for each patient based on the proposed LET-incorporated optimization (LETOpt) and the conventional dose-based optimization (DoseOpt). The optimized plans were compared in terms of both dose (assuming a constant RBE of 1.1 as adopted in clinical practice) and LET. Both optimization approaches were able to generate comparable dose distributions. The LET-incorporated optimization achieved not only pronounced reduction of LET values in critical organs, such as brainstem and optic chiasm, but also increased LET in target volumes, compared to the conventional dose-based optimization. However, on occasion, there was a need to tradeoff the acceptability of dose and LET distributions. Our conclusion is that the

  15. Whole-brain hippocampal sparing radiation therapy: Volume-modulated arc therapy vs intensity-modulated radiation therapy case study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Katrina, E-mail: Trinabena23@gmail.com; Lenards, Nishele; Holson, Janice

    2016-04-01

    The hippocampus is responsible for memory and cognitive function. An ongoing phase II clinical trial suggests that sparing dose to the hippocampus during whole-brain radiation therapy can help preserve a patient's neurocognitive function. Progressive research and advancements in treatment techniques have made treatment planning more sophisticated but beneficial for patients undergoing treatment. The aim of this study is to evaluate and compare hippocampal sparing whole-brain (HS-WB) radiation therapy treatment planning techniques using volume-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT). We randomly selected 3 patients to compare different treatment techniques that could be used for reducing dose to the hippocampal region. We created 2 treatment plans, a VMAT and an IMRT, from each patient's data set and planned on the Eclipse 11.0 treatment planning system (TPS). A total of 6 plans (3 IMRT and 3 VMAT) were created and evaluated for this case study. The physician contoured the hippocampus as per the Radiation Therapy Oncology Group (RTOG) 0933 protocol atlas. The organs at risk (OR) were contoured and evaluated for the plan comparison, which included the spinal cord, optic chiasm, the right and left eyes, lenses, and optic nerves. Both treatment plans produced adequate coverage on the planning target volume (PTV) while significantly reducing dose to the hippocampal region. The VMAT treatment plans produced a more homogenous dose distribution throughout the PTV while decreasing the maximum point dose to the target. However, both treatment techniques demonstrated hippocampal sparing when irradiating the whole brain.

  16. Whole-brain hippocampal sparing radiation therapy: Volume-modulated arc therapy vs intensity-modulated radiation therapy case study.

    Science.gov (United States)

    Lee, Katrina; Lenards, Nishele; Holson, Janice

    2016-01-01

    The hippocampus is responsible for memory and cognitive function. An ongoing phase II clinical trial suggests that sparing dose to the hippocampus during whole-brain radiation therapy can help preserve a patient׳s neurocognitive function. Progressive research and advancements in treatment techniques have made treatment planning more sophisticated but beneficial for patients undergoing treatment. The aim of this study is to evaluate and compare hippocampal sparing whole-brain (HS-WB) radiation therapy treatment planning techniques using volume-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT). We randomly selected 3 patients to compare different treatment techniques that could be used for reducing dose to the hippocampal region. We created 2 treatment plans, a VMAT and an IMRT, from each patient׳s data set and planned on the Eclipse 11.0 treatment planning system (TPS). A total of 6 plans (3 IMRT and 3 VMAT) were created and evaluated for this case study. The physician contoured the hippocampus as per the Radiation Therapy Oncology Group (RTOG) 0933 protocol atlas. The organs at risk (OR) were contoured and evaluated for the plan comparison, which included the spinal cord, optic chiasm, the right and left eyes, lenses, and optic nerves. Both treatment plans produced adequate coverage on the planning target volume (PTV) while significantly reducing dose to the hippocampal region. The VMAT treatment plans produced a more homogenous dose distribution throughout the PTV while decreasing the maximum point dose to the target. However, both treatment techniques demonstrated hippocampal sparing when irradiating the whole brain. Copyright © 2016 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  17. Comparative analysis of 60Co intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Fox, Christopher; Romeijn, H Edwin; Lynch, Bart; Dempsey, James F; Men, Chunhua; Aleman, Dionne M

    2008-01-01

    In this study, we perform a scientific comparative analysis of using 60 Co beams in intensity-modulated radiation therapy (IMRT). In particular, we evaluate the treatment plan quality obtained with (i) 6 MV, 18 MV and 60 Co IMRT; (ii) different numbers of static multileaf collimator (MLC) delivered 60 Co beams and (iii) a helical tomotherapy 60 Co beam geometry. We employ a convex fluence map optimization (FMO) model, which allows for the comparison of plan quality between different beam energies and configurations for a given case. A total of 25 clinical patient cases that each contain volumetric CT studies, primary and secondary delineated targets, and contoured structures were studied: 5 head-and-neck (H and N), 5 prostate, 5 central nervous system (CNS), 5 breast and 5 lung cases. The DICOM plan data were anonymized and exported to the University of Florida optimized radiation therapy (UFORT) treatment planning system. The FMO problem was solved for each case for 5-71 equidistant beams as well as a helical geometry for H and N, prostate, CNS and lung cases, and for 3-7 equidistant beams in the upper hemisphere for breast cases, all with 6 MV, 18 MV and 60 Co dose models. In all cases, 95% of the target volumes received at least the prescribed dose with clinical sparing criteria for critical organs being met for all structures that were not wholly or partially contained within the target volume. Improvements in critical organ sparing were found with an increasing number of equidistant 60 Co beams, yet were marginal above 9 beams for H and N, prostate, CNS and lung. Breast cases produced similar plans for 3-7 beams. A helical 60 Co beam geometry achieved similar plan quality as static plans with 11 equidistant 60 Co beams. Furthermore, 18 MV plans were initially found not to provide the same target coverage as 6 MV and 60 Co plans; however, adjusting the trade-offs in the optimization model allowed equivalent target coverage for 18 MV. For plans with comparable

  18. Intensity-modulated radiation therapy for anal carcinoma

    International Nuclear Information System (INIS)

    Peiffert, D.; Moreau-Claeys, M.V.; Tournier-Rangeard, L.; Huger, S.; Marchesi, V.

    2011-01-01

    Anal canal carcinoma are highly curable by irradiation, combined with chemotherapy in locally advanced disease, with preservation of sphincter function. The clinical target volume for the nodes is extended, often including the inguinal nodes, which is not usual for other pelvic tumours. Acute and late effects are correlated with the volume and dose delivered to organs at risk, i. e. small bowel, bladder and increased by concomitant chemotherapy. Intensity modulated irradiation (IMRT) makes it possible to optimize the dose distribution in this 'complex U shaped' volume, while maintaining the dose distribution for the target volumes. The conversion from conformal irradiation to IMRT necessitates good knowledge of the definition and skills to delineate target volumes and organs at risk, including new volumes needed to optimize the dose distribution. Dosimetric and clinical benefits of IMRT are described, based on early descriptions and evidence-based publication. The growing development of IMRT in anal canal radiotherapy must be encouraged, and long-term benefits should be soon published. Radiation oncologists should precisely learn IMRT recommendations before starting the technique, and evaluate its early and late results for adverse effects, but also for long-term tumour control. (authors)

  19. Feasibility of a unified approach to intensity-modulated radiation therapy and volume-modulated arc therapy optimization and delivery

    International Nuclear Information System (INIS)

    Hoover, Douglas A.; Chen, Jeff Z.; MacFarlane, Michael; Wong, Eugene; Battista, Jerry J.

    2015-01-01

    Purpose: To study the feasibility of unified intensity-modulated arc therapy (UIMAT) which combines intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) optimization and delivery to produce superior radiation treatment plans, both in terms of dose distribution and efficiency of beam delivery when compared with either VMAT or IMRT alone. Methods: An inverse planning algorithm for UIMAT was prototyped within the PINNACLE treatment planning system (Philips Healthcare). The IMRT and VMAT deliveries are unified within the same arc, with IMRT being delivered at specific gantry angles within the arc. Optimized gantry angles for the IMRT and VMAT phases are assigned automatically by the inverse optimization algorithm. Optimization of the IMRT and VMAT phases is done simultaneously using a direct aperture optimization algorithm. Five treatment plans each for prostate, head and neck, and lung were generated using a unified optimization technique and compared with clinical IMRT or VMAT plans. Delivery verification was performed with an ArcCheck phantom (Sun Nuclear) on a Varian TrueBeam linear accelerator (Varian Medical Systems). Results: In this prototype implementation, the UIMAT plans offered the same target dose coverage while reducing mean doses to organs at risk by 8.4% for head-and-neck cases, 5.7% for lung cases, and 3.5% for prostate cases, compared with the VMAT or IMRT plans. In addition, UIMAT can be delivered with similar efficiency as VMAT. Conclusions: In this proof-of-concept work, a novel radiation therapy optimization and delivery technique that interlaces VMAT or IMRT delivery within the same arc has been demonstrated. Initial results show that unified VMAT/IMRT has the potential to be superior to either standard IMRT or VMAT

  20. Simultaneous beam geometry and intensity map optimization in intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Lee, Eva K.; Fox, Tim; Crocker, Ian

    2006-01-01

    Purpose: In current intensity-modulated radiation therapy (IMRT) plan optimization, the focus is on either finding optimal beam angles (or other beam delivery parameters such as field segments, couch angles, gantry angles) or optimal beam intensities. In this article we offer a mixed integer programming (MIP) approach for simultaneously determining an optimal intensity map and optimal beam angles for IMRT delivery. Using this approach, we pursue an experimental study designed to (a) gauge differences in plan quality metrics with respect to different tumor sites and different MIP treatment planning models, and (b) test the concept of critical-normal-tissue-ring-a tissue ring of 5 mm thickness drawn around the planning target volume (PTV)-and its use for designing conformal plans. Methods and Materials: Our treatment planning models use two classes of decision variables to capture the beam configuration and intensities simultaneously. Binary (0/1) variables are used to capture 'on' or 'off' or 'yes' or 'no' decisions for each field, and nonnegative continuous variables are used to represent intensities of beamlets. Binary and continuous variables are also used for each voxel to capture dose level and dose deviation from target bounds. Treatment planning models were designed to explicitly incorporate the following planning constraints: (a) upper/lower/mean dose-based constraints, (b) dose-volume and equivalent-uniform-dose (EUD) constraints for critical structures, (c) homogeneity constraints (underdose/overdose) for PTV, (d) coverage constraints for PTV, and (e) maximum number of beams allowed. Within this constrained solution space, five optimization strategies involving clinical objectives were analyzed: optimize total intensity to PTV, optimize total intensity and then optimize conformity, optimize total intensity and then optimize homogeneity, minimize total dose to critical structures, minimize total dose to critical structures and optimize conformity

  1. Conformal radiation therapy with or without intensity modulation in the treatment of localized prostate cancer

    International Nuclear Information System (INIS)

    Maingon, P.; Truc, G.; Bosset, M.; Peignaux, K.; Ammor, A.; Bolla, M.

    2005-01-01

    Conformal radiation therapy has now to be considered as a standard treatment of localized prostatic adenocarcinomas. Using conformational methods and intensity modulated radiation therapy requires a rigorous approach for their implementation in routine, focused on the reproducibility of the treatment, target volume definitions, dosimetry, quality control, setup positioning. In order to offer to the largest number of patients high-dose treatment, the clinicians must integrate as prognostic factors accurate definition of microscopic extension as well as the tolerance threshold of critical organs. High-dose delivery is expected to be most efficient in intermediary risks and locally advanced diseases. Intensity modulated radiation therapy is specifically dedicated to dose escalation. Perfect knowledge of classical constraints of conformal radiation therapy is required. Using such an approach in routine needs a learning curve including the physicists and a specific quality assurance program. (author)

  2. Head and neck intensity modulated radiation therapy leads to an increase of opportunistic oral pathogens

    NARCIS (Netherlands)

    Schuurhuis, Jennifer M.; Stokman, Monique A.; Witjes, Max J. H.; Langendijk, Johannes A.; van Winkelhoff, Arie J.; Vissink, Arjan; Spijkervet, Frederik K. L.

    Objectives: The introduction of intensity modulated radiation therapy (IMRT) has led to new possibilities in the treatment of head and neck cancer (HNC). Limited information is available on how this more advanced radiation technique affects the oral microflora. In a prospective study we assessed the

  3. Intensity Modulated Proton Therapy Versus Intensity Modulated Photon Radiation Therapy for Oropharyngeal Cancer: First Comparative Results of Patient-Reported Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Sio, Terence T. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, Mayo Clinic, Scottsdale, Arizona (United States); Lin, Huei-Kai; Shi, Qiuling [Department of Symptom Research, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gunn, G. Brandon [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Cleeland, Charles S. [Department of Symptom Research, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Lee, J. Jack; Hernandez, Mike [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Blanchard, Pierre; Thaker, Nikhil G.; Phan, Jack; Rosenthal, David I.; Garden, Adam S.; Morrison, William H.; Fuller, C. David [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mendoza, Tito R. [Department of Symptom Research, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wang, Xin Shelley [Department of Symptom Research, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Frank, Steven J., E-mail: sjfrank@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2016-07-15

    Purpose: We hypothesized that patients with oropharyngeal cancer treated with intensity modulated proton therapy (IMPT) would have lower symptom burdens, as measured by patient-reported outcome (PRO) surveys, than patients treated with intensity modulated photon therapy (IMRT). Methods and Materials: Patients were treated for oropharyngeal cancer from 2006 to 2015 through prospective registries with concurrent chemotherapy and IMPT or chemotherapy and IMRT and completed the MD Anderson Symptom Inventory for Head and Neck Cancer (MDASI-HN) module at various times before treatment (baseline), during treatment (acute phase), within the first 3 months after treatment (subacute phase), and afterward (chronic phase). Individual symptoms and the top 5 and top 11 most severe symptoms were summarized and compared between the radiation therapy modalities. Results: PRO data were collected and analyzed from 35 patients treated with chemotherapy and IMPT and from 46 treated with chemotherapy and IMRT. The baseline symptom burdens were similar between both groups. The overall top 5 symptoms were food taste problems (mean score 4.91 on a 0-10 scale), dry mouth (4.49), swallowing/chewing difficulties (4.26), lack of appetite (4.08), and fatigue (4.00). Among the top 11 symptoms, changes in taste and appetite during the subacute and chronic phases favored IMPT (all P<.048). No differences in symptom burden were detected between modalities during the acute and chronic phases by top-11 symptom scoring. During the subacute phase, the mean (±standard deviation) top 5 MDASI scores were 5.15 ± 2.66 for IMPT versus 6.58 ± 1.98 for IMRT (P=.013). Conclusions: According to the MDASI-HN, symptom burden was lower among the IMPT patients than among the IMRT patients during the subacute recovery phase after treatment. A prospective randomized clinical trial is underway to define the value of IMPT for the management of head and neck tumors.

  4. Intensity Modulated Proton Therapy Versus Intensity Modulated Photon Radiation Therapy for Oropharyngeal Cancer: First Comparative Results of Patient-Reported Outcomes

    International Nuclear Information System (INIS)

    Sio, Terence T.; Lin, Huei-Kai; Shi, Qiuling; Gunn, G. Brandon; Cleeland, Charles S.; Lee, J. Jack; Hernandez, Mike; Blanchard, Pierre; Thaker, Nikhil G.; Phan, Jack; Rosenthal, David I.; Garden, Adam S.; Morrison, William H.; Fuller, C. David; Mendoza, Tito R.; Mohan, Radhe; Wang, Xin Shelley; Frank, Steven J.

    2016-01-01

    Purpose: We hypothesized that patients with oropharyngeal cancer treated with intensity modulated proton therapy (IMPT) would have lower symptom burdens, as measured by patient-reported outcome (PRO) surveys, than patients treated with intensity modulated photon therapy (IMRT). Methods and Materials: Patients were treated for oropharyngeal cancer from 2006 to 2015 through prospective registries with concurrent chemotherapy and IMPT or chemotherapy and IMRT and completed the MD Anderson Symptom Inventory for Head and Neck Cancer (MDASI-HN) module at various times before treatment (baseline), during treatment (acute phase), within the first 3 months after treatment (subacute phase), and afterward (chronic phase). Individual symptoms and the top 5 and top 11 most severe symptoms were summarized and compared between the radiation therapy modalities. Results: PRO data were collected and analyzed from 35 patients treated with chemotherapy and IMPT and from 46 treated with chemotherapy and IMRT. The baseline symptom burdens were similar between both groups. The overall top 5 symptoms were food taste problems (mean score 4.91 on a 0-10 scale), dry mouth (4.49), swallowing/chewing difficulties (4.26), lack of appetite (4.08), and fatigue (4.00). Among the top 11 symptoms, changes in taste and appetite during the subacute and chronic phases favored IMPT (all P<.048). No differences in symptom burden were detected between modalities during the acute and chronic phases by top-11 symptom scoring. During the subacute phase, the mean (±standard deviation) top 5 MDASI scores were 5.15 ± 2.66 for IMPT versus 6.58 ± 1.98 for IMRT (P=.013). Conclusions: According to the MDASI-HN, symptom burden was lower among the IMPT patients than among the IMRT patients during the subacute recovery phase after treatment. A prospective randomized clinical trial is underway to define the value of IMPT for the management of head and neck tumors.

  5. Cardiac Exposure in the Dynamic Conformal Arc Therapy, Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy of Lung Cancer.

    Directory of Open Access Journals (Sweden)

    Xin Ming

    Full Text Available To retrospectively evaluate the cardiac exposure in three cohorts of lung cancer patients treated with dynamic conformal arc therapy (DCAT, intensity-modulated radiotherapy (IMRT, or volumetric modulated arc therapy (VMAT at our institution in the past seven years.A total of 140 lung cancer patients were included in this institutional review board approved study: 25 treated with DCAT, 70 with IMRT and 45 with VMAT. All plans were generated in a same commercial treatment planning system and have been clinically accepted and delivered. The dose distribution to the heart and the effects of tumor laterality, the irradiated heart volume and the beam-to-heart distance on the cardiac exposure were investigated.The mean dose to the heart among all 140 plans was 4.5 Gy. Specifically, the heart received on average 2.3, 5.2 and 4.6 Gy in the DCAT, IMRT and VMAT plans, respectively. The mean heart doses for the left and right lung tumors were 4.1 and 4.8 Gy, respectively. No patients died with evidence of cardiac disease. Three patients (2% with preexisting cardiac condition developed cardiac disease after treatment. Furthermore, the cardiac exposure was found to increase linearly with the irradiated heart volume while decreasing exponentially with the beam-to-heart distance.Compared to old technologies for lung cancer treatment, modern radiotherapy treatment modalities demonstrated better heart sparing. But the heart dose in lung cancer radiotherapy is still higher than that in the radiotherapy of breast cancer and Hodgkin's disease where cardiac complications have been extensively studied. With strong correlations of mean heart dose with beam-to-heart distance and irradiated heart volume, cautions should be exercised to avoid long-term cardiac toxicity in the lung cancer patients undergoing radiotherapy.

  6. Comparison study of intensity modulated arc therapy using single or multiple arcs to intensity modulated radiation therapy for high-risk prostate cancer

    International Nuclear Information System (INIS)

    Ashamalla, Hani; Tejwani, Ajay; Parameritis, Loannis; Swamy, Uma; Luo, Pei Ching; Guirguis, Adel; Lavaf, Amir

    2013-01-01

    Intensity modulated arc therapy (IMAT) is a form of intensity modulated radiation therapy (IMRT) that delivers dose in single or multiple arcs. We compared IMRT plans versus single-arc field (1ARC) and multi-arc fields (3ARC) IMAT plans in high-risk prostate cancer. Sixteen patients were studied. Prostate (PTV P ), right pelvic (PTV RtLN ) and left pelvic lymph nodes (PTV LtLN ), and organs at risk were contoured. PTVP, PTV RtLN , and PTV LtLN received 50.40 Gy followed by a boost to PTV B of 28.80 Gy. Three plans were per patient generated: IMRT, 1ARC, and 3ARC. We recorded the dose to the PTV, the mean dose (D MEAN ) to the organs at risk, and volume covered by the 50% isodose. Efficiency was evaluated by monitor units (MU) and beam on time (BOT). Conformity index (CI), Paddick gradient index, and homogeneity index (HI) were also calculated. Average Radiation Therapy Oncology Group CI was 1.17, 1.20, and 1.15 for IMRT, 1ARC, and 3ARC, respectively. The plans' HI were within 1% of each other. The D MEAN of bladder was within 2% of each other. The rectum D MEAN in IMRT plans was 10% lower dose than the arc plans (p < 0.0001). The GI of the 3ARC was superior to IMRT by 27.4% (p = 0.006). The average MU was highest in the IMRT plans (1686) versus 1ARC (575) versus 3ARC (1079). The average BOT was 6 minutes for IMRT compared to 1.3 and 2.9 for 1ARC and 3ARC IMAT (p < 0.05). For high-risk prostate cancer, IMAT may offer a favorable dose gradient profile, conformity, MU and BOT compared to IMRT.

  7. Delivery confirmation of bolus electron conformal therapy combined with intensity modulated x-ray therapy

    International Nuclear Information System (INIS)

    Kavanaugh, James A.; Hogstrom, Kenneth R.; Fontenot, Jonas P.; Henkelmann, Gregory; Chu, Connel; Carver, Robert A.

    2013-01-01

    Purpose: The purpose of this study was to demonstrate that a bolus electron conformal therapy (ECT) dose plan and a mixed beam plan, composed of an intensity modulated x-ray therapy (IMXT) dose plan optimized on top of the bolus ECT plan, can be accurately delivered. Methods: Calculated dose distributions were compared with measured dose distributions for parotid and chest wall (CW) bolus ECT and mixed beam plans, each simulated in a cylindrical polystyrene phantom that allowed film dose measurements. Bolus ECT plans were created for both parotid and CW PTVs (planning target volumes) using 20 and 16 MeV beams, respectively, whose 90% dose surface conformed to the PTV. Mixed beam plans consisted of an IMXT dose plan optimized on top of the bolus ECT dose plan. The bolus ECT, IMXT, and mixed beam dose distributions were measured using radiographic films in five transverse and one sagittal planes for a total of 36 measurement conditions. Corrections for film dose response, effects of edge-on photon irradiation, and effects of irregular phantom optical properties on the Cerenkov component of the film signal resulted in high precision measurements. Data set consistency was verified by agreement of depth dose at the intersections of the sagittal plane with the five measured transverse planes. For these same depth doses, results for the mixed beam plan agreed with the sum of the individual depth doses for the bolus ECT and IMXT plans. The six mean measured planar dose distributions were compared with those calculated by the treatment planning system for all modalities. Dose agreement was assessed using the 4% dose difference and 0.2 cm distance to agreement. Results: For the combined high-dose region and low-dose region, pass rates for the parotid and CW plans were 98.7% and 96.2%, respectively, for the bolus ECT plans and 97.9% and 97.4%, respectively, for the mixed beam plans. For the high-dose gradient region, pass rates for the parotid and CW plans were 93.1% and 94

  8. Intensity-modulated radiation therapy: a review with a physics perspective.

    Science.gov (United States)

    Cho, Byungchul

    2018-03-01

    Intensity-modulated radiation therapy (IMRT) has been considered the most successful development in radiation oncology since the introduction of computed tomography into treatment planning that enabled three-dimensional conformal radiotherapy in 1980s. More than three decades have passed since the concept of inverse planning was first introduced in 1982, and IMRT has become the most important and common modality in radiation therapy. This review will present developments in inverse IMRT treatment planning and IMRT delivery using multileaf collimators, along with the associated key concepts. Other relevant issues and future perspectives are also presented.

  9. RADIATION THERAPY COMMUNICATION-REIRRADIATION OF A NASAL TUMOR IN A BRACHYCEPHALIC DOG USING INTENSITY MODULATED RADIATION THERAPY.

    Science.gov (United States)

    Rancilio, Nicholas J; Custead, Michelle R; Poulson, Jean M

    2016-09-01

    A 5-year-old spayed female Shih Tzu was referred for evaluation of a nasal transitional carcinoma. A total lifetime dose of 117 Gy was delivered to the intranasal mass in three courses over nearly 2 years using fractionated intensity modulated radiation therapy (IMRT) to spare normal tissues. Clinically significant late normal tissue side effects were limited to bilaterally diminished tear production. The patient died of metastatic disease progression 694 days after completion of radiation therapy course 1. This case demonstrates that retreatment with radiation therapy to high lifetime doses for recurrent local disease may be well tolerated with IMRT. © 2016 American College of Veterinary Radiology.

  10. Radiation-Induced Cancers From Modern Radiotherapy Techniques: Intensity-Modulated Radiotherapy Versus Proton Therapy

    International Nuclear Information System (INIS)

    Yoon, Myonggeun; Ahn, Sung Hwan; Kim, Jinsung; Shin, Dong Ho; Park, Sung Yong; Lee, Se Byeong; Shin, Kyung Hwan; Cho, Kwan Ho

    2010-01-01

    Purpose: To assess and compare secondary cancer risk resulting from intensity-modulated radiotherapy (IMRT) and proton therapy in patients with prostate and head-and-neck cancer. Methods and Materials: Intensity-modulated radiotherapy and proton therapy in the scattering mode were planned for 5 prostate caner patients and 5 head-and-neck cancer patients. The secondary doses during irradiation were measured using ion chamber and CR-39 detectors for IMRT and proton therapy, respectively. Organ-specific radiation-induced cancer risk was estimated by applying organ equivalent dose to dose distributions. Results: The average secondary doses of proton therapy for prostate cancer patients, measured 20-60cm from the isocenter, ranged from 0.4 mSv/Gy to 0.1 mSv/Gy. The average secondary doses of IMRT for prostate patients, however, ranged between 3 mSv/Gy and 1 mSv/Gy, approximately one order of magnitude higher than for proton therapy. Although the average secondary doses of IMRT were higher than those of proton therapy for head-and-neck cancers, these differences were not significant. Organ equivalent dose calculations showed that, for prostate cancer patients, the risk of secondary cancers in out-of-field organs, such as the stomach, lungs, and thyroid, was at least 5 times higher for IMRT than for proton therapy, whereas the difference was lower for head-and-neck cancer patients. Conclusions: Comparisons of organ-specific organ equivalent dose showed that the estimated secondary cancer risk using scattering mode in proton therapy is either significantly lower than the cases in IMRT treatment or, at least, does not exceed the risk induced by conventional IMRT treatment.

  11. Clinical Outcomes of Intensity-Modulated Pelvic Radiation Therapy for Carcinoma of the Cervix

    International Nuclear Information System (INIS)

    Hasselle, Michael D.; Rose, Brent S.; Kochanski, Joel D.; Nath, Sameer K.; Bafana, Rounak; Yashar, Catheryn M.; Hasan, Yasmin; Roeske, John C.; Mundt, Arno J.; Mell, Loren K.

    2011-01-01

    Purpose: To evaluate disease outcomes and toxicity in cervical cancer patients treated with pelvic intensity-modulated radiation therapy (IMRT). Methods and Materials: We included all patients with Stage I-IVA cervical carcinoma treated with IMRT at three different institutions from 2000-2007. Patients treated with extended field or conventional techniques were excluded. Intensity-modulated radiation therapy plans were designed to deliver 45 Gy in 1.8-Gy daily fractions to the planning target volume while minimizing dose to the bowel, bladder, and rectum. Toxicity was graded according to the Radiation Therapy Oncology Group system. Overall survival and disease-free survival were estimated by use of the Kaplan-Meier method. Pelvic failure, distant failure, and late toxicity were estimated by use of cumulative incidence functions. Results: The study included 111 patients. Of these, 22 were treated with postoperative IMRT, 8 with IMRT followed by intracavitary brachytherapy and adjuvant hysterectomy, and 81 with IMRT followed by planned intracavitary brachytherapy. Of the patients, 63 had Stage I-IIA disease and 48 had Stage IIB-IVA disease. The median follow-up time was 27 months. The 3-year overall survival rate and the disease-free survival rate were 78% (95% confidence interval [CI], 68-88%) and 69% (95% CI, 59-81%), respectively. The 3-year pelvic failure rate and the distant failure rate were 14% (95% CI, 6-22%) and 17% (95% CI, 8-25%), respectively. Estimates of acute and late Grade 3 toxicity or higher were 2% (95% CI, 0-7%) and 7% (95% CI, 2-13%), respectively. Conclusions: Intensity-modulated radiation therapy is associated with low toxicity and favorable outcomes, supporting its safety and efficacy for cervical cancer. Prospective clinical trials are needed to evaluate the comparative efficacy of IMRT vs. conventional techniques.

  12. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    OpenAIRE

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-01-01

    Introduction Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation ...

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

    International Nuclear Information System (INIS)

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

    2003-01-01

    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

  14. Radiochromic film in the dosimetric verification of intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Zhou Yingjuan; Huang Shaomin; Deng Xiaowu

    2007-01-01

    Objective: Objective To investigate the dose-response behavior of a new type of radio- chromic film( GAFCHROMIC EBT) and explore the clinical application means and precision of dosage measurement, which can be applied for: (1) plan-specific dosimetric verification for intensity modulated radiation therapy, (2) to simplify the process of quality assurance using traditional radiographic film dosimetric system and (3) to establish a more reliable, more efficient dosimetric verification system for intensity modulated radiation therapy. Methods: (1) The step wedge calibration technique was used to calibrate EBT radiochromic film and EDR2 radiographic film. The dose characteristics, the measurement consistency and the quality assurance process between the two methods were compared. (2) The in-phantom dose-measurement based verification technique has been adopted. Respectively, EBT film and EDR2 film were used to measure the same dose plane of IMRT treatment plans. The results of the dose map, dose profiles and iso- dose curves were compared with those calculated by CORVUS treatment planning system to evaluate the function of EBT film for dosimetric verification for intensity modulated radiation therapy. Results: (1) Over the external beam dosimetric range of 0-500 cGy, EBT/VXR-16 and EDR2/VXR-16 film dosimetric system had the same measurement consistency with the measurement variability less then 0.70%. The mean measurement variability of these two systems was 0.37% and 0.68%, respectively. The former proved to be the superior modality at measurement consistency, reliability, and efficiency over dynamic clinical dose range , furthermore, its quality assurance showed less process than the latter. (2) The dosimetric verification of IMRT plane measured with EBT film was quite similar to that with EDR2 film which was processed under strict quality control. In a plane of the phantom, the maximal dose deviation off axis between EBT film measurement and the TPS calculation was

  15. Validation of intensity modulated radiation therapy patient plans with portal images

    International Nuclear Information System (INIS)

    Delpon, G.; Warren, S.; Mahe, D.; Gaudaire, S.; Lisbona, A.

    2007-01-01

    The goal of this study was to show the feasibility of step and shoot intensity-modulated radiation therapy pre-treatment quality control for patients using the electronic portal imaging device (iViewGT) fitted on a Sli+ linac (Elekta Oncology Systems, Crawley, UK) instead of radiographic films. Since the beginning of intensity-modulated radiation therapy treatments, the dosimetric quality control necessary before treating each new patient has been a time-consuming and therefore costly obligation. In order to fully develop this technique, it seems absolutely essential to reduce the cost of these controls, especially the linac time. Up to now, verification of the relative dosimetry field by field has been achieved by acquiring radiographic films in the isocenter plane and comparing them to the results of the XiO planning system (Computerized Medical Systems, Missouri, USA) using RIT113 v4.1 software (Radiological Imaging Technology, Colorado, USA). A qualitative and quantitative evaluation was realised for every field of every patient. A quick and simple procedure was put into place to be able to make the same verifications using portal images. This new technique is not a modification of the overall methodology of analysis. The results achieved by comparing the measurement with the electronic portal imaging device and the calculation with the treatment planning system were in line with those achieved with the films for all indicators we studied (isodoses, horizontal and vertical dose profiles and gamma index). (authors)

  16. Role of beam orientation optimization in intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Pugachev, Andrei; Li, Jonathan G.; Boyer, Arthur L.; Hancock, Steven L.; Le, Quynh-Thu; Donaldson, Sarah S.; Lei Xing

    2001-01-01

    Purpose: To investigate the role of beam orientation optimization in intensity-modulated radiation therapy (IMRT) and to examine the potential benefits of noncoplanar intensity-modulated beams. Methods and Materials: A beam orientation optimization algorithm was implemented. For this purpose, system variables were divided into two groups: beam position (gantry and table angles) and beam profile (beamlet weights). Simulated annealing was used for beam orientation optimization and the simultaneous iterative inverse treatment planning algorithm (SIITP) for beam intensity profile optimization. Three clinical cases were studied: a localized prostate cancer, a nasopharyngeal cancer, and a paraspinal tumor. Nine fields were used for all treatments. For each case, 3 types of treatment plan optimization were performed: (1) beam intensity profiles were optimized for 9 equiangular spaced coplanar beams; (2) orientations and intensity profiles were optimized for 9 coplanar beams; (3) orientations and intensity profiles were optimized for 9 noncoplanar beams. Results: For the localized prostate case, all 3 types of optimization described above resulted in dose distributions of a similar quality. For the nasopharynx case, optimized noncoplanar beams provided a significant gain in the gross tumor volume coverage. For the paraspinal case, orientation optimization using noncoplanar beams resulted in better kidney sparing and improved gross tumor volume coverage. Conclusion: The sensitivity of an IMRT treatment plan with respect to the selection of beam orientations varies from site to site. For some cases, the choice of beam orientations is important even when the number of beams is as large as 9. Noncoplanar beams provide an additional degree of freedom for IMRT treatment optimization and may allow for notable improvement in the quality of some complicated plans

  17. Accommodating practical constraints for intensity modulated radiation therapy by means of compensators

    International Nuclear Information System (INIS)

    Meyer, Juergen

    2002-01-01

    The thesis deals with the practical implementation of intensity modulated radiation therapy (IMRT) generated by means of patient specific metal compensators. An elaborate comparison between several compensator-machining techniques, with respect to their suitability for production within a hospital workshop, is presented. The limitations associated with the selected compensator manufacturing technique are identified and implemented as constraints in an existing inverse treatment-planning algorithm. In order to obtain the profile of a compensator, which produces a desired intensity distribution, inverse modeling of the radiation attenuation within the compensator is required. Two novel and independent approaches, based on deconvolution and system identification, are proposed to accomplish this. To compare the approach with the 'rival' state of the art beam modulation technique, a theoretical and experimental examination of the modulated fields generated by manufactured compensators and multileaf collimators is presented. This comparison focused on the achievable resolution of the intensity modulated beams in lateral and longitudinal directions. To take into account the characteristics of a clinical environment the suitability of the most common commercially available treatment couch systems for IMRT treatments is studied. An original rule based advisory system is developed to alert the operator of any potential collision of the beam with the movable supporting structures of the treatment couch. The system is capable of finding alternative positions for the supporting frames and, if necessary, can suggest alternative beam directions. Finally, a head and neck phantom is designed for gel dosimetry to assess IMRT treatment delivery techniques. The phantom is based on a simplistic but realistic design and contains the main anatomical features

  18. The survival analysis on localized prostate cancer treated with neoadjuvant endocrine therapy followed by intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Gao Hong; Li Gaofeng; Wu Qinhong; Li Xuenan; Zhong Qiuzi; Xu Yonggang

    2010-01-01

    Objective: To retrospectively investigate clinical outcomes and prognostic factors in localized prostate cancer treated with neoadjuvant endocrine therapy followed by intensity modulated radiotherapy (IMRT). Methods: Between March 2003 and October 2008, 54 localized prostate cancer treated by IMRT were recruited. All patients had received endocrine therapy before IMRT. The endocrine therapy included surgical castration or medical castration in combination with antiandrogens. The target of IMRT was the prostate and seminal vesicles with or without pelvis. The biochemical failure was defined according to the phoenix definition. By using the risk grouping standard proposed by D'Amico, patients were divided into three groups: low-risk group (n = 5), intermediate-risk group (n = 12), and high-risk group (n = 37). Kaplan-Meier method was used to calculate the overall survival rate. Prognostic factors were analyzed by univariate and multiple Cox regression analysis. Results: The follow-up rate was 98%. The number of patients under follow-up was 39 at 3 years and 25 at 5 years. Potential prognostic factors, including risk groups, mode of endocrine therapy, time of endocrine therapy, phoenix grouping before IMRT, the prostate specific antigen doubling time (PSADT) before radiotherapy, PSA value before IMRT, interval of endocrine therapy and IMRT, irradiation region, and irradiation dose were analyzed by survival analysis. In univariate analysis, time of endocrine therapy (75 % vs 95 %, χ 2 = 6. 45, P = 0. 011), phoenix grouping before IMRT (87% vs 96%, χ 2 = 4. 36, P = 0. 037), interval of endocrine therapy and IMRT (80% vs 95%, χ 2 = 11.60, P= 0. 001), irradiation dose (75% vs 91%, χ 2 =5.92, P= 0. 015) were statistically significant prognostic factors for 3 - year overall survival , and risk groups (85 vs 53 vs 29, χ 2 = 6. 40, P =0. 041) and PSADT before IMRT (62 vs 120, U =24. 50, P =0. 003) were significant factors for the median survival time. In the multiple Cox

  19. A comparison of three optimization algorithms for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Pflugfelder, D.; Wilkens, J.J.; Nill, S.; Oelfke, U.

    2008-01-01

    In intensity modulated treatment techniques, the modulation of each treatment field is obtained using an optimization algorithm. Multiple optimization algorithms have been proposed in the literature, e.g. steepest descent, conjugate gradient, quasi-Newton methods to name a few. The standard optimization algorithm in our in-house inverse planning tool KonRad is a quasi-Newton algorithm. Although this algorithm yields good results, it also has some drawbacks. Thus we implemented an improved optimization algorithm based on the limited-memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) routine. In this paper the improved optimization algorithm is described. To compare the two algorithms, several treatment plans are optimized using both algorithms. This included photon (IMRT) as well as proton (IMPT) intensity modulated therapy treatment plans. To present the results in a larger context the widely used conjugate gradient algorithm was also included into this comparison. On average, the improved optimization algorithm was six times faster to reach the same objective function value. However, it resulted not only in an acceleration of the optimization. Due to the faster convergence, the improved optimization algorithm usually terminates the optimization process at a lower objective function value. The average of the observed improvement in the objective function value was 37%. This improvement is clearly visible in the corresponding dose-volume-histograms. The benefit of the improved optimization algorithm is particularly pronounced in proton therapy plans. The conjugate gradient algorithm ranked in between the other two algorithms with an average speedup factor of two and an average improvement of the objective function value of 30%. (orig.)

  20. Trends in intensity modulated radiation therapy use for locally advanced rectal cancer at National Comprehensive Cancer Network centers

    OpenAIRE

    Marsha Reyngold, MD, PhD; Joyce Niland, PhD; Anna ter Veer, MS; Tanios Bekaii-Saab, MD; Lily Lai, MD; Joshua E. Meyer, MD; Steven J. Nurkin, MD, MS; Deborah Schrag, MD, MPH; John M. Skibber, MD, FACS; Al B. Benson, MD; Martin R. Weiser, MD; Christopher H. Crane, MD; Karyn A. Goodman, MD, MS

    2018-01-01

    Purpose: Intensity modulated radiation therapy (IMRT) has been rapidly incorporated into clinical practice because of its technological advantages over 3-dimensional conformal radiation therapy (CRT). We characterized trends in IMRT utilization in trimodality treatment of locally advanced rectal cancer at National Comprehensive Cancer Network cancer centers between 2005 and 2011. Methods and materials: Using the prospective National Comprehensive Cancer Network Colorectal Cancer Database, ...

  1. Direct aperture optimization as a means of reducing the complexity of intensity modulated radiation therapy plans

    International Nuclear Information System (INIS)

    Broderick, Maria; Leech, Michelle; Coffey, Mary

    2009-01-01

    Intensity Modulated Radiation Therapy (IMRT) is a means of delivering radiation therapy where the intensity of the beam is varied within the treatment field. This is done by dividing a large beam into many small beamlets. Dose constraints are assigned to both the target and sensitive structures and computerised inverse optimization is performed to find the individual weights of this large number of beamlets. The computer adjusts the intensities of these beamlets according to the required planning dose objectives. The optimized intensity patterns are then decomposed into a series of deliverable multi leaf collimator (MLC) shapes in the sequencing step. One of the main problems of IMRT, which becomes even more apparent as the complexity of the IMRT plan increases, is the dramatic increase in the number of Monitor Units (MU) required to deliver a fractionated treatment. The difficulty with this increase in MU is its association with increased treatment times and a greater leakage of radiation from the MLCs increasing the total body dose and the risk of secondary cancers in patients. Therefore one attempts to find ways of reducing these MU without compromising plan quality. The design of inverse planning systems where the beam is divided into small beamlets to produce the required intensity map automatically introduces complexity into IMRT treatment planning. Plan complexity is associated with many negative factors such as dosimetric uncertainty and delivery issues A large search space is required necessitating much computing power. However, the limitations of the delivery technology are not taken into consideration when designing the ideal intensity map therefore a further step termed the sequencing step is required to convert the ideal intensity map into a deliverable one. Many approaches have been taken to reduce the complexity. These include setting intensity limits, putting penalties on the cost function and using smoothing filters Direct Aperture optimization

  2. Direct aperture optimization as a means of reducing the complexity of intensity modulated radiation therapy plans

    Directory of Open Access Journals (Sweden)

    Coffey Mary

    2009-02-01

    Full Text Available Abstract Intensity Modulated Radiation Therapy (IMRT is a means of delivering radiation therapy where the intensity of the beam is varied within the treatment field. This is done by dividing a large beam into many small beamlets. Dose constraints are assigned to both the target and sensitive structures and computerised inverse optimization is performed to find the individual weights of this large number of beamlets. The computer adjusts the intensities of these beamlets according to the required planning dose objectives. The optimized intensity patterns are then decomposed into a series of deliverable multi leaf collimator (MLC shapes in the sequencing step. One of the main problems of IMRT, which becomes even more apparent as the complexity of the IMRT plan increases, is the dramatic increase in the number of Monitor Units (MU required to deliver a fractionated treatment. The difficulty with this increase in MU is its association with increased treatment times and a greater leakage of radiation from the MLCs increasing the total body dose and the risk of secondary cancers in patients. Therefore one attempts to find ways of reducing these MU without compromising plan quality. The design of inverse planning systems where the beam is divided into small beamlets to produce the required intensity map automatically introduces complexity into IMRT treatment planning. Plan complexity is associated with many negative factors such as dosimetric uncertainty and delivery issues A large search space is required necessitating much computing power. However, the limitations of the delivery technology are not taken into consideration when designing the ideal intensity map therefore a further step termed the sequencing step is required to convert the ideal intensity map into a deliverable one. Many approaches have been taken to reduce the complexity. These include setting intensity limits, putting penalties on the cost function and using smoothing filters Direct

  3. Direct aperture optimization as a means of reducing the complexity of intensity modulated radiation therapy plans

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Maria; Leech, Michelle; Coffey, Mary [Division of Radiation Therapy, School of Medicine, Trinity College Dublin, Dublin, Ireland (United Kingdom)

    2009-02-16

    Intensity Modulated Radiation Therapy (IMRT) is a means of delivering radiation therapy where the intensity of the beam is varied within the treatment field. This is done by dividing a large beam into many small beamlets. Dose constraints are assigned to both the target and sensitive structures and computerised inverse optimization is performed to find the individual weights of this large number of beamlets. The computer adjusts the intensities of these beamlets according to the required planning dose objectives. The optimized intensity patterns are then decomposed into a series of deliverable multi leaf collimator (MLC) shapes in the sequencing step. One of the main problems of IMRT, which becomes even more apparent as the complexity of the IMRT plan increases, is the dramatic increase in the number of Monitor Units (MU) required to deliver a fractionated treatment. The difficulty with this increase in MU is its association with increased treatment times and a greater leakage of radiation from the MLCs increasing the total body dose and the risk of secondary cancers in patients. Therefore one attempts to find ways of reducing these MU without compromising plan quality. The design of inverse planning systems where the beam is divided into small beamlets to produce the required intensity map automatically introduces complexity into IMRT treatment planning. Plan complexity is associated with many negative factors such as dosimetric uncertainty and delivery issues A large search space is required necessitating much computing power. However, the limitations of the delivery technology are not taken into consideration when designing the ideal intensity map therefore a further step termed the sequencing step is required to convert the ideal intensity map into a deliverable one. Many approaches have been taken to reduce the complexity. These include setting intensity limits, putting penalties on the cost function and using smoothing filters Direct Aperture optimization

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

    Science.gov (United States)

    Sengbusch, Evan R.

    , beamlet weight, the number of delivered beamlets, and the number of delivery angles. These methods are evaluated via treatment planning studies including left-sided whole breast irradiation, lung stereotactic body radiotherapy, nasopharyngeal carcinoma, and whole brain radiotherapy with hippocampal avoidance. Improvements in efficiency and efficacy relative to traditional proton therapy and intensity modulated photon radiation therapy are discussed.

  5. Comparison of volumetric modulated arc therapy and intensity modulated radiation therapy for whole brain hippocampal sparing treatment plans based on radiobiological modeling

    Directory of Open Access Journals (Sweden)

    Ethan Kendall

    2018-01-01

    Full Text Available Introduction: In this article, we report the results of our investigation on comparison of radiobiological aspects of treatment plans with linear accelerator-based intensity-modulated radiation therapy and volumetric-modulated arc therapy for patients having hippocampal avoidance whole-brain radiation therapy. Materials and Methods: In this retrospective study using the dose-volume histogram, we calculated and compared biophysical indices of equivalent uniform dose, tumor control probability, and normal tissue complication probability (NTCP for 15 whole-brain radiotherapy patients. Results and Discussions: Dose-response models for tumors and critical structures were separated into two groups: mechanistic and empirical. Mechanistic models formulate mathematically with describable relationships while empirical models fit data through empirical observations to appropriately determine parameters giving results agreeable to those given by mechanistic models. Conclusions: Techniques applied in this manuscript could be applied to any other organs or types of cancer to evaluate treatment plans based on radiobiological modeling.

  6. A comparison of the quality assurance of four dosimetric tools for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Son, Jaeman; Baek, Taesung; Lee, Boram; Shin, Dongho; Park, Sung Yong; Park, Jeonghoon; Lim, Young Kyung; Lee, Se Byeong; Kim, Jooyoung; Yoon, Myonggeun

    2015-01-01

    This study was designed to compare the quality assurance (QA) results of four dosimetric tools used for intensity modulated radiation therapy (IMRT) and to suggest universal criteria for the passing rate in QA, irrespective of the dosimetric tool used. Thirty fields of IMRT plans from five patients were selected, followed by irradiation onto radiochromic film, a diode array (Mapcheck), an ion chamber array (MatriXX) and an electronic portal imaging device (EPID) for patient-specific QA. The measured doses from the four dosimetric tools were compared with the dose calculated by the treatment planning system. The passing rates of the four dosimetric tools were calculated using the gamma index method, using as criteria a dose difference of 3% and a distance-to-agreement of 3 mm. The QA results based on Mapcheck, MatriXX and EPID showed good agreement, with average passing rates of 99.61%, 99.04% and 99.29%, respectively. However, the average passing rate based on film measurement was significantly lower, 95.88%. The average uncertainty (1 standard deviation) of passing rates for 6 intensity modulated fields was around 0.31 for film measurement, larger than those of the other three dosimetric tools. QA results and consistencies depend on the choice of dosimetric tool. Universal passing rates should depend on the normalization or inter-comparisons of dosimetric tools if more than one dosimetric tool is used for patient specific QA

  7. A comparison of the quality assurance of four dosimetric tools for intensity modulated radiation therapy.

    Science.gov (United States)

    Son, Jaeman; Baek, Taesung; Lee, Boram; Shin, Dongho; Park, Sung Yong; Park, Jeonghoon; Lim, Young Kyung; Lee, Se Byeong; Kim, Jooyoung; Yoon, Myonggeun

    2015-09-01

    This study was designed to compare the quality assurance (QA) results of four dosimetric tools used for intensity modulated radiation therapy (IMRT) and to suggest universal criteria for the passing rate in QA, irrespective of the dosimetric tool used. Thirty fields of IMRT plans from five patients were selected, followed by irradiation onto radiochromic film, a diode array (Mapcheck), an ion chamber array (MatriXX) and an electronic portal imaging device (EPID) for patient-specific QA. The measured doses from the four dosimetric tools were compared with the dose calculated by the treatment planning system. The passing rates of the four dosimetric tools were calculated using the gamma index method, using as criteria a dose difference of 3% and a distance-to-agreement of 3 mm. The QA results based on Mapcheck, MatriXX and EPID showed good agreement, with average passing rates of 99.61%, 99.04% and 99.29%, respectively. However, the average passing rate based on film measurement was significantly lower, 95.88%. The average uncertainty (1 standard deviation) of passing rates for 6 intensity modulated fields was around 0.31 for film measurement, larger than those of the other three dosimetric tools. QA results and consistencies depend on the choice of dosimetric tool. Universal passing rates should depend on the normalization or inter-comparisons of dosimetric tools if more than one dosimetric tool is used for patient specific QA.

  8. Accuracy of Real-time Couch Tracking During 3-dimensional Conformal Radiation Therapy, Intensity Modulated Radiation Therapy, and Volumetric Modulated Arc Therapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Wilbert, Juergen; Baier, Kurt; Hermann, Christian; Flentje, Michael; Guckenberger, Matthias

    2013-01-01

    Purpose: To evaluate the accuracy of real-time couch tracking for prostate cancer. Methods and Materials: Intrafractional motion trajectories of 15 prostate cancer patients were the basis for this phantom study; prostate motion had been monitored with the Calypso System. An industrial robot moved a phantom along these trajectories, motion was detected via an infrared camera system, and the robotic HexaPOD couch was used for real-time counter-steering. Residual phantom motion during real-time tracking was measured with the infrared camera system. Film dosimetry was performed during delivery of 3-dimensional conformal radiation therapy (3D-CRT), step-and-shoot intensity modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT). Results: Motion of the prostate was largest in the anterior–posterior direction, with systematic (∑) and random (σ) errors of 2.3 mm and 2.9 mm, respectively; the prostate was outside a threshold of 5 mm (3D vector) for 25.0%±19.8% of treatment time. Real-time tracking reduced prostate motion to ∑=0.01 mm and σ = 0.55 mm in the anterior–posterior direction; the prostate remained within a 1-mm and 5-mm threshold for 93.9%±4.6% and 99.7%±0.4% of the time, respectively. Without real-time tracking, pass rates based on a γ index of 2%/2 mm in film dosimetry ranged between 66% and 72% for 3D-CRT, IMRT, and VMAT, on average. Real-time tracking increased pass rates to minimum 98% on average for 3D-CRT, IMRT, and VMAT. Conclusions: Real-time couch tracking resulted in submillimeter accuracy for prostate cancer, which transferred into high dosimetric accuracy independently of whether 3D-CRT, IMRT, or VMAT was used.

  9. Intrafraction Motion in Stereotactic Body Radiation Therapy for Non-Small Cell Lung Cancer: Intensity Modulated Radiation Therapy Versus Volumetric Modulated Arc Therapy

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    Rossi, Maddalena M.G.; Peulen, Heike M.U.; Belderbos, Josè S.A.; Sonke, Jan-Jakob, E-mail: j.sonke@nki.nl

    2016-06-01

    Purpose: Stereotactic body radiation therapy (SBRT) for early-stage inoperable non-small cell lung cancer (NSCLC) patients delivers high doses that require high-precision treatment. Typically, image guidance is used to minimize day-to-day target displacement, but intrafraction position variability is often not corrected. Currently, volumetric modulated arc therapy (VMAT) is replacing intensity modulated radiation therapy (IMRT) in many departments because of its shorter delivery time. This study aimed to evaluate whether intrafraction variation in VMAT patients is reduced in comparison with patients treated with IMRT. Methods and Materials: NSCLC patients (197 IMRT and 112 VMAT) treated with a frameless SBRT technique to a prescribed dose of 3 × 18 Gy were evaluated. Image guidance for both techniques was identical: pretreatment cone beam computed tomography (CBCT) (CBCT{sub precorr}) for setup correction followed immediately before treatment by postcorrection CBCT (CBCT{sub postcorr}) for verification. Then, after either a noncoplanar IMRT technique or a VMAT technique, a posttreatment (CBCT{sub postRT}) scan was acquired. The CBCT{sub postRT} and CBCT{sub postcorr} scans were then used to evaluate intrafraction motion. Treatment delivery times, systematic (Σ) and random (σ) intrafraction variations, and associated planning target volume (PTV) margins were calculated. Results: The median treatment delivery time was significantly reduced by 20 minutes (range, 32-12 minutes) using VMAT compared with noncoplanar IMRT. Intrafraction tumor motion was significantly larger for IMRT in all directions up to 0.5 mm systematic (Σ) and 0.7 mm random (σ). The required PTV margins for IMRT and VMAT differed by less than 0.3 mm. Conclusion: VMAT-based SBRT for NSCLC was associated with significantly shorter delivery times and correspondingly smaller intrafraction motion compared with noncoplanar IMRT. However, the impact on the required PTV margin was small.

  10. Spinal cordd biological safety comparison of intensity modulated radiotherapy and conventional radiation therapy

    International Nuclear Information System (INIS)

    Xilinbaoleri; Xu Wanlong; Chen Gang; Liu Hao; Wang Ruozheng; Bai Jingping

    2010-01-01

    Objective: To compare the spine intensity modulated radiation therapy (IMRT) and the conventional radiation therapy on the beagle spinal cord neurons, in order to prove the biological safety of IMRT of the spinal cord. Methods: Twelve selected purebred beagles were randomly divided into 2 groups. A beagle clinical model of tumor was mimiced in the ninth and tenth thoracic vertebrae. Then the beagles were irradiated by 2 different models of intensity modulated radiotherapy and conventional radiation therapy, with the total irradiation doses of 50 and 70 Gy. The samples of spinal cord were taken out from the same position of the nine and tenth thoracic vertebrae at the third month after radiation.All the samples were observed by the electron microscope, and the Fas and HSP70 expression in spinal cord neurons were evaluated by immunohistochemistry method. Terminal deoxynucleatidyl transferase mediated dUTP nick and labeling (TUNEL) technique was used to examine the apoptotic cells in the spinal cord. Results: The neurons in the spinal cord of IMRT group were mainly reversible injury, and those in the conventional radiation therapy were mainly apoptosis. Compared with the conventional radiation therapy group [50 Gy group, (7.3 ± 1.1)%; 70 Gy group, (11.3 ± 1.4)%], the apoptosis rate of the spinal cord neurons of the intensity modulated radiotherapy group [50 Gy group, (1.2 ± 0.7)%; 70 Gy group (2.5 ± 0.8)%] was much lower[(50 Gy group, t=0.022, P<0.05; 70 Gy group, t=0.017, P<0.05)]. The expression levels of Fas in the IMPT group (50 Gy group, 4.6 ± 0.8; 70 Gy group, 7.4 ± 1.1) were also much lowerthan those in the other group (50 Gy group, 15.1 ± 6.4; 70 Gy group, 19.3 ± 7.6. 50 Gy group, t=0.231, P<0.05; 70 Gy group, t=0.457, P<0.05), while the expression levels of HSP70 in the IMPT group (50 Gy group, 9.1 ± 0.8; 70 Gy group, 7.3 ± 1.4)were much higher than those in the conventional radiation therapy group (50 Gy group, 2.1 ± 0.9; 70 Gy group, 1.7 ± 0

  11. American Society of Radiation Oncology Recommendations for Documenting Intensity-Modulated Radiation Therapy Treatments

    International Nuclear Information System (INIS)

    Holmes, Timothy; Das, Rupak; Low, Daniel; Yin Fangfang; Balter, James; Palta, Jatinder; Eifel, Patricia

    2009-01-01

    Despite the widespread use of intensity-modulated radiation therapy (IMRT) for approximately a decade, a lack of adequate guidelines for documenting these treatments persists. Proper IMRT treatment documentation is necessary for accurate reconstruction of prior treatments when a patient presents with a marginal recurrence. This is especially crucial when the follow-up care is managed at a second treatment facility not involved in the initial IMRT treatment. To address this issue, an American Society for Radiation Oncology (ASTRO) workgroup within the American ASTRO Radiation Physics Committee was formed at the request of the ASTRO Research Council to develop a set of recommendations for documenting IMRT treatments. This document provides a set of comprehensive recommendations for documenting IMRT treatments, as well as image-guidance procedures, with example forms provided.

  12. Matching Intensity-Modulated Radiation Therapy to an Anterior Low Neck Field

    International Nuclear Information System (INIS)

    Amdur, Robert J.; Liu, Chihray; Li, Jonathan; Mendenhall, William; Hinerman, Russell

    2007-01-01

    When using intensity-modulated radiation therapy (IMRT) to treat head and neck cancer with the primary site above the level of the larynx, there are two basic options for the low neck lymphatics: to treat the entire neck with IMRT, or to match the IMRT plan to a conventional anterior 'low neck' field. In view of the potential advantages of using a conventional low neck field, it is important to look for ways to minimize or manage the problems of matching IMRT to a conventional radiotherapy field. Treating the low neck with a single anterior field and the standard larynx block decreases the dose to the larynx and often results in a superior IMRT plan at the primary site. The purpose of this article is to review the most applicable studies and to discuss our experience with implementing a technique that involves moving the position of the superior border of the low neck field several times during a single treatment fraction

  13. A method of segment weight optimization for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Pei Xi; Cao Ruifen; Jing Jia; Cheng Mengyun; Zheng Huaqing; Li Jia; Huang Shanqing; Li Gui; Song Gang; Wang Weihua; Wu Yican; FDS Team

    2011-01-01

    The error caused by leaf sequencing often leads to planning of Intensity-Modulated Radiation Therapy (IMRT) arrange system couldn't meet clinical demand. The optimization approach in this paper can reduce this error and improve efficiency of plan-making effectively. Conjugate Gradient algorithm was used to optimize segment weight and readjust segment shape, which could minimize the error anterior-posterior leaf sequencing eventually. Frequent clinical cases were tasted by precise radiotherapy system, and then compared Dose-Volume histogram between target area and organ at risk as well as isodose line in computed tomography (CT) film, we found that the effect was improved significantly after optimizing segment weight. Segment weight optimizing approach based on Conjugate Gradient method can make treatment planning meet clinical request more efficiently, so that has extensive application perspective. (authors)

  14. Volumetric Modulated Arc Therapy for Spine Radiosurgery: Superior Treatment Planning and Delivery Compared to Static Beam Intensity Modulated Radiotherapy.

    Science.gov (United States)

    Zach, Leor; Tsvang, Lev; Alezra, Dror; Ben Ayun, Maoz; Harel, Ran

    2016-01-01

    Spine stereotactic radiosurgery (SRS) delivers an accurate and efficient high radiation dose to vertebral metastases in 1-5 fractions. We aimed to compare volumetric modulated arc therapy (VMAT) to static beam intensity modulated radiotherapy (IMRT) for spine SRS. Ten spine lesions of previously treated SRS patients were planned retrospectively using both IMRT and VMAT with a prescribed dose of 16 Gy to 100% of the planning target volume (PTV). The plans were compared for conformity, homogeneity, treatment delivery time, and safety (spinal cord dose). All evaluated parameters favored the VMAT plan over the IMRT plans. D min in the IMRT was significantly lower than in the VMAT plan (7.65 Gy/10.88 Gy, p DSC) was found to be significantly better for the VMAT plans compared to the IMRT plans (0.77/0.58, resp., p  value < 0.01), and an almost 50% reduction in the net treatment time was calculated for the VMAT compared to the IMRT plans (6.73 min/12.96 min, p < 0.001). In our report, VMAT provides better conformity, homogeneity, and safety profile. The shorter treatment time is a major advantage and not only provides convenience to the painful patient but also contributes to the precision of this high dose radiation therapy.

  15. Volumetric Modulated Arc Therapy for Spine Radiosurgery: Superior Treatment Planning and Delivery Compared to Static Beam Intensity Modulated Radiotherapy

    Directory of Open Access Journals (Sweden)

    Leor Zach

    2016-01-01

    Full Text Available Purpose. Spine stereotactic radiosurgery (SRS delivers an accurate and efficient high radiation dose to vertebral metastases in 1–5 fractions. We aimed to compare volumetric modulated arc therapy (VMAT to static beam intensity modulated radiotherapy (IMRT for spine SRS. Methods and Materials. Ten spine lesions of previously treated SRS patients were planned retrospectively using both IMRT and VMAT with a prescribed dose of 16 Gy to 100% of the planning target volume (PTV. The plans were compared for conformity, homogeneity, treatment delivery time, and safety (spinal cord dose. Results. All evaluated parameters favored the VMAT plan over the IMRT plans. Dmin in the IMRT was significantly lower than in the VMAT plan (7.65 Gy/10.88 Gy, p<0.001, the Dice Similarity Coefficient (DSC was found to be significantly better for the VMAT plans compared to the IMRT plans (0.77/0.58, resp., p  value<0.01, and an almost 50% reduction in the net treatment time was calculated for the VMAT compared to the IMRT plans (6.73 min/12.96 min, p<0.001. Conclusions. In our report, VMAT provides better conformity, homogeneity, and safety profile. The shorter treatment time is a major advantage and not only provides convenience to the painful patient but also contributes to the precision of this high dose radiation therapy.

  16. Intensity-modulated radiation therapy: overlapping co-axial modulated fields

    International Nuclear Information System (INIS)

    Metcalfe, P; Tangboonduangjit, P; White, P

    2004-01-01

    The Varian multi-leaf collimator has a 14.5 cm leaf extension limit from each carriage. This means the target volumes in the head and neck region are sometimes too wide for standard width-modulated fields to provide adequate dose coverage. A solution is to set up asymmetric co-axial overlapping fields. This protects the MLC carriage while in return the MLC provides modulated dose blending in the field overlap region. Planar dose maps for coincident fields from the Pinnacle radiotherapy treatment planning system are compared with planar dose maps reconstructed from radiographic film and electronic portal images. The film and portal images show small leaf-jaw matchlines at each field overlap border. Linear profiles taken across each image show that the observed leaf-jaw matchlines from the accelerator images are not accounted for by the treatment planning system. Dose difference between film reconstructed electronic portal images and planning system are about 2.5 cGy in a modulated field at d max . While the magnitude of the dose differences are small improved round end leaf modelling combined with a finer dose calculation grid may minimize the discrepancy between calculated and delivered dose

  17. Dosimetric and QA aspects of Konrad inverse planning system for commissioning intensity-modulated radiation therapy

    Directory of Open Access Journals (Sweden)

    Deshpande Shrikant

    2007-01-01

    Full Text Available The intensity-modulated radiation therapy (IMRT planning is performed using the Konrad inverse treatment planning system and the delivery of the treatment by using Siemens Oncor Impression Plus linear accelerator (step and shoot, which has been commissioned recently. The basic beam data required for commissioning the system were generate. The quality assurance of relative and absolute dose distribution was carried out before clinical implementation. The salient features of Konrad planning system, like dependence of grid size on dose volume histogram (DVH, number of intensity levels and step size in sequencer, are studied quantitatively and qualitatively. To verify whether the planned dose [from treatment planning system (TPS] and delivered dose are the same, the absolute dose at a point is determined using CC01 ion chamber and the axial plane dose distribution is carried out using Kodak EDR2 in conjunction with OmniPro IMRT Phantom and OmniPro IMRT software from Scanditronix Wellhofer. To obtain the optimum combination in leaf sequencer module, parameters like number of intensity levels, step size are analyzed. The difference between pixel values of optimum fluence profile and the fluence profile obtained for various combinations of number of intensity levels and step size is compared and plotted. The calculations of the volume of any RT structure in the dose volume histogram are compared using grid sizes 3 mm and 4 mm. The measured and planned dose at a point showed good agreement (< 3% except for a few cases wherein the chamber was placed in a relatively high dose gradient region. The axial plane dose distribution using film dosimetry shows excellent agreement (correlation coefficient> 0.97 in all the cases. In the leaf sequencer module, the combination of number of intensity level 7 with step size of 3 is the optimal solution for obtaining deliverable segments. The RT structure volume calculation is found to be more accurate with grid size of

  18. [Intensity modulated radiation therapy for patients with gynecological malignancies after hysterectomy and chemotherapy/radiotherapy].

    Science.gov (United States)

    Chen, Zhen-yun; Ma, Yue-bing; Sheng, Xiu-gui; Zhang, Xiao-ling; Xue, Li; Song, Qu-qing; Liu, Nai-fu; Miao, Hua-qin

    2007-04-01

    To investigate the value of intensity modulated radiation therapy (IMRT) for patient with gynecological malignancies after treatment of hysterectomy and chemotherapy/radiotherapy. All 32 patients with cervical or endometrial cancer after hysterectomy received full course IMRT after 1 to 3 cycles of chemotherapy (Karnofsky performance status(KPS) > or =70). Seventeen of these patients underwent postoperative preventive irradiation and the other 15 patients were pelvic wall recurrence and/or retroperitoneal lymph node metastasis, though postoperative radiotherapy and/or chemotherapy had been given after operation. The median dose delivered to the PTV was 56.8 Gy for preventive irradiation, and 60.6 Gy for pelvic wall recurrence or retroperioneal lymph node metastasis irradiation. It was required that 90% of iso-dose curve could covere more than 99% of GTV. However, The mean dose irradiated to small intestine, bladder, rectum, kidney and spinal cord was 21.3 Gy, 37.8 Gy, 35.3 Gy, 8.5 Gy, 22.1 Gy, respectively. Fourteen patients presented grade I (11 patients) or II (3 patients) digestive tract side-effects, Five patients developed grade I or II bone marrow depression. Twelve patients had grade I skin reaction. The overall 1-year survival rate was 100%. The 2- and 3- year survival rate for preventive irradiation were both 100%, but which was 5/7 and 3/6 for the patients with pelvic wall recurrence or retroperioneal lymph node metastasis. Intensity modulated radiation therapy can provide a better dose distribution than traditional radiotherapy for both prevention and pelvic wall recurrence or retroperioneal lymph node metastasis. The toxicity is tolerable. The adjacent organs at risk can well be protected.

  19. Intensity-modulated radiation therapy to bilateral lower limb extremities concurrently: a planning case study

    Energy Technology Data Exchange (ETDEWEB)

    Fitzgerald, Emma, E-mail: emmafitz1390@gmail.com; Miles, Wesley; Fenton, Paul; Frantzis, Jim [Radiation Oncology, Epworth HealthCare, Victoria (Australia)

    2014-09-15

    Non-melanomatous skin cancers represent 80% of all newly diagnosed cancers in Australia with basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) being the most common. A previously healthy 71-year-old woman presented with widespread and tender superficial skin cancers on the lower bilateral limbs. External beam radiation therapy through the use of intensity-modulated radiation therapy (IMRT) was employed as the treatment modality of choice as this technique provides conformal dose distribution to a three-dimensional treatment volume while reducing toxicity to surrounding tissues. The patient was prescribed a dose of 60 Gy to the planning target volume (PTV) with 1.0 cm bolus over the ventral surface of each limb. The beam arrangement consisted of six treatment fields that avoided entry and exit through the contralateral limb. The treatment plans met the International Commission on Radiation Units and Measurements (ICRU) guidelines and produced highly conformal dosimetric results. Skin toxicity was measured against the National Cancer Institute: Common Terminology Criteria for Adverse Events (NCI: CTCAE) version 3. A well-tolerated treatment was delivered with excellent results given the initial extent of the disease. This case study has demonstrated the feasibility and effectiveness of IMRT for skin cancers as an alternative to surgery and traditional superficial radiation therapy, utilising a complex PTV of the extremities for patients with similar presentations.

  20. Improved Outcomes with Intensity Modulated Radiation Therapy Combined with Temozolomide for Newly Diagnosed Glioblastoma Multiforme

    Directory of Open Access Journals (Sweden)

    Noel J. Aherne

    2014-01-01

    Full Text Available Purpose. Glioblastoma multiforme (GBM is optimally treated by maximal debulking followed by combined chemoradiation. Intensity modulated radiation therapy (IMRT is gaining widespread acceptance in other tumour sites, although evidence to support its use over three-dimensional conformal radiation therapy (3DCRT in the treatment of gliomas is currently lacking. We examined the survival outcomes for patients with GBM treated with IMRT and Temozolomide. Methods and Materials. In all, 31 patients with GBM were treated with IMRT and 23 of these received chemoradiation with Temozolomide. We correlated survival outcomes with patient functional status, extent of surgery, radiation dose, and use of chemotherapy. Results. Median survival for all patients was 11.3 months, with a median survival of 7.2 months for patients receiving 40.05 Gray (Gy and a median survival of 17.4 months for patients receiving 60 Gy. Conclusions. We report one of the few series of IMRT in patients with GBM. In our group, median survival for those receiving 60 Gy with Temozolomide compared favourably to the combined therapy arm of the largest randomised trial of chemoradiation versus radiation to date (17.4 months versus 14.6 months. We propose that IMRT should be considered as an alternative to 3DCRT for patients with GBM.

  1. Improved outcomes with intensity modulated radiation therapy combined with temozolomide for newly diagnosed glioblastoma multiforme.

    Science.gov (United States)

    Aherne, Noel J; Benjamin, Linus C; Horsley, Patrick J; Silva, Thomaz; Wilcox, Shea; Amalaseelan, Julan; Dwyer, Patrick; Tahir, Abdul M R; Hill, Jacques; Last, Andrew; Hansen, Carmen; McLachlan, Craig S; Lee, Yvonne L; McKay, Michael J; Shakespeare, Thomas P

    2014-01-01

    Purpose. Glioblastoma multiforme (GBM) is optimally treated by maximal debulking followed by combined chemoradiation. Intensity modulated radiation therapy (IMRT) is gaining widespread acceptance in other tumour sites, although evidence to support its use over three-dimensional conformal radiation therapy (3DCRT) in the treatment of gliomas is currently lacking. We examined the survival outcomes for patients with GBM treated with IMRT and Temozolomide. Methods and Materials. In all, 31 patients with GBM were treated with IMRT and 23 of these received chemoradiation with Temozolomide. We correlated survival outcomes with patient functional status, extent of surgery, radiation dose, and use of chemotherapy. Results. Median survival for all patients was 11.3 months, with a median survival of 7.2 months for patients receiving 40.05 Gray (Gy) and a median survival of 17.4 months for patients receiving 60 Gy. Conclusions. We report one of the few series of IMRT in patients with GBM. In our group, median survival for those receiving 60 Gy with Temozolomide compared favourably to the combined therapy arm of the largest randomised trial of chemoradiation versus radiation to date (17.4 months versus 14.6 months). We propose that IMRT should be considered as an alternative to 3DCRT for patients with GBM.

  2. Linear Energy Transfer-Guided Optimization in Intensity Modulated Proton Therapy: Feasibility Study and Clinical Potential

    Energy Technology Data Exchange (ETDEWEB)

    Giantsoudi, Drosoula, E-mail: dgiantsoudi@partners.org [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Grassberger, Clemens; Craft, David; Niemierko, Andrzej; Trofimov, Alexei; Paganetti, Harald [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States)

    2013-09-01

    Purpose: To investigate the feasibility and potential clinical benefit of linear energy transfer (LET) guided plan optimization in intensity modulated proton therapy (IMPT). Methods and Materials: A multicriteria optimization (MCO) module was used to generate a series of Pareto-optimal IMPT base plans (BPs), corresponding to defined objectives, for 5 patients with head-and-neck cancer and 2 with pancreatic cancer. A Monte Carlo platform was used to calculate dose and LET distributions for each BP. A custom-designed MCO navigation module allowed the user to interpolate between BPs to produce deliverable Pareto-optimal solutions. Differences among the BPs were evaluated for each patient, based on dose–volume and LET–volume histograms and 3-dimensional distributions. An LET-based relative biological effectiveness (RBE) model was used to evaluate the potential clinical benefit when navigating the space of Pareto-optimal BPs. Results: The mean LET values for the target varied up to 30% among the BPs for the head-and-neck patients and up to 14% for the pancreatic cancer patients. Variations were more prominent in organs at risk (OARs), where mean LET values differed by a factor of up to 2 among the BPs for the same patient. An inverse relation between dose and LET distributions for the OARs was typically observed. Accounting for LET-dependent variable RBE values, a potential improvement on RBE-weighted dose of up to 40%, averaged over several structures under study, was noticed during MCO navigation. Conclusions: We present a novel strategy for optimizing proton therapy to maximize dose-averaged LET in tumor targets while simultaneously minimizing dose-averaged LET in normal tissue structures. MCO BPs show substantial LET variations, leading to potentially significant differences in RBE-weighted doses. Pareto-surface navigation, using both dose and LET distributions for guidance, provides the means for evaluating a large variety of deliverable plans and aids in

  3. Linear Energy Transfer-Guided Optimization in Intensity Modulated Proton Therapy: Feasibility Study and Clinical Potential

    International Nuclear Information System (INIS)

    Giantsoudi, Drosoula; Grassberger, Clemens; Craft, David; Niemierko, Andrzej; Trofimov, Alexei; Paganetti, Harald

    2013-01-01

    Purpose: To investigate the feasibility and potential clinical benefit of linear energy transfer (LET) guided plan optimization in intensity modulated proton therapy (IMPT). Methods and Materials: A multicriteria optimization (MCO) module was used to generate a series of Pareto-optimal IMPT base plans (BPs), corresponding to defined objectives, for 5 patients with head-and-neck cancer and 2 with pancreatic cancer. A Monte Carlo platform was used to calculate dose and LET distributions for each BP. A custom-designed MCO navigation module allowed the user to interpolate between BPs to produce deliverable Pareto-optimal solutions. Differences among the BPs were evaluated for each patient, based on dose–volume and LET–volume histograms and 3-dimensional distributions. An LET-based relative biological effectiveness (RBE) model was used to evaluate the potential clinical benefit when navigating the space of Pareto-optimal BPs. Results: The mean LET values for the target varied up to 30% among the BPs for the head-and-neck patients and up to 14% for the pancreatic cancer patients. Variations were more prominent in organs at risk (OARs), where mean LET values differed by a factor of up to 2 among the BPs for the same patient. An inverse relation between dose and LET distributions for the OARs was typically observed. Accounting for LET-dependent variable RBE values, a potential improvement on RBE-weighted dose of up to 40%, averaged over several structures under study, was noticed during MCO navigation. Conclusions: We present a novel strategy for optimizing proton therapy to maximize dose-averaged LET in tumor targets while simultaneously minimizing dose-averaged LET in normal tissue structures. MCO BPs show substantial LET variations, leading to potentially significant differences in RBE-weighted doses. Pareto-surface navigation, using both dose and LET distributions for guidance, provides the means for evaluating a large variety of deliverable plans and aids in

  4. Sensitivity of intensity modulated proton therapy plans to changes in patient weight

    International Nuclear Information System (INIS)

    Albertini, Francesca; Bolsi, Alessandra; Lomax, Antony J.; Rutz, Hans Peter; Timmerman, Beate; Goitein, Gudrun

    2008-01-01

    Purpose: A retrospective study to investigate the sensitivity of intensity modulated proton therapy (IMPT) to changes in body weight occurring during the course of radiotherapy for patients treated in the sacral region. Materials and methods: During therapy, important weight gain and loss were observed for two patients treated to para-spinal tumors, which resulted in both patients being re-scanned and re-planned. Both patients were treated as part of their therapy, with a narrow-angle IMPT (NA-IMPT) plan delivering a 'dose hole' around the cauda equina (CE), which was mainly formed through modulation of Bragg peaks in depth. To investigate the impact of these weight changes on the proton range and delivered dose, the nominal fields were re-calculated on the new CT data sets. Results were analyzed by comparing these new plans with those originally delivered and by calculating changes in range and delivered doses in target volumes and normal tissues. Results: Maximum differences in proton range in the CE region of up to +8 mm and -13 mm, respectively, for the patient who gained weight and for the patient who lost weight, increased the maximum dose to the CE by only 2%. This indicates that both IMPT plans were relatively insensitive to substantial range uncertainties. Even greater differences in range (16 mm) in the planning target volume only slightly affected its dose homogeneity (differences in V 90% of 6% in the worst case). Nevertheless, some large undesired local dose differences were observed. Conclusions: We demonstrated, that, at least for the two analyzed cases, NA-IMPT plans are less sensitive to weight variations than one may expect. Still, we would advise to calculate new plans in case of substantial change in weight for patients treated in the sacral region, primarily due to the presence of new hot/cold area

  5. Dosimetric advantages of intensity-modulated proton therapy for oropharyngeal cancer compared with intensity-modulated radiation: A case-matched control analysis

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    Holliday, Emma B. [Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX (United States); Kocak-Uzel, Esengul [Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX (United States); Department of Radiation Therapy, Beykent University, Istanbul (Turkey); Feng, Lei [Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX (United States); Thaker, Nikhil G.; Blanchard, Pierre; Rosenthal, David I.; Gunn, G. Brandon; Garden, Adam S. [Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX (United States); Frank, Steven J., E-mail: sjfrank@mdanderson.org [Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2016-10-01

    A potential advantage of intensity-modulated proton therapy (IMPT) over intensity-modulated (photon) radiation therapy (IMRT) in the treatment of oropharyngeal carcinoma (OPC) is lower radiation dose to several critical structures involved in the development of nausea and vomiting, mucositis, and dysphagia. The purpose of this study was to quantify doses to critical structures for patients with OPC treated with IMPT and compare those with doses on IMRT plans generated for the same patients and with a matched cohort of patients actually treated with IMRT. In this study, 25 patients newly diagnosed with OPC were treated with IMPT between 2011 and 2012. Comparison IMRT plans were generated for these patients and for additional IMRT-treated controls extracted from a database of patients with OPC treated between 2000 and 2009. Cases were matched based on the following criteria, in order: unilateral vs bilateral therapy, tonsil vs base of tongue primary, T-category, N-category, concurrent chemotherapy, induction chemotherapy, smoking status, sex, and age. Results showed that the mean doses to the anterior and posterior oral cavity, hard palate, larynx, mandible, and esophagus were significantly lower with IMPT than with IMRT comparison plans generated for the same cohort, as were doses to several central nervous system structures involved in the nausea and vomiting response. Similar differences were found when comparing dose to organs at risks (OARs) between the IMPT cohort and the case-matched IMRT cohort. In conclusion, these findings suggest that patients with OPC treated with IMPT may experience fewer and less severe side effects during therapy. This may be the result of decreased beam path toxicities with IMPT due to lower doses to several dysphagia, odynophagia, and nausea and vomiting–associated OARs. Further study is needed to evaluate differences in long-term disease control and chronic toxicity between patients with OPC treated with IMPT in comparison to

  6. Clinical Outcomes and Patterns of Disease Recurrence After Intensity Modulated Proton Therapy for Oropharyngeal Squamous Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Gunn, G. Brandon [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Blanchard, Pierre [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, Institut Gustave Roussy, Villejuif (France); Garden, Adam S. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhu, X. Ronald [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Fuller, C. David [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Medical Physics Program, The University of Texas Graduate School of Biomedical Sciences, Houston, Texas (United States); Mohamed, Abdallah S. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Clinical Oncology and Nuclear Medicine, University of Alexandria (Egypt); Morrison, William H.; Phan, Jack; Beadle, Beth M.; Skinner, Heath D. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Sturgis, Erich M. [Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Kies, Merrill S. [Department of Thoracic/Head and Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Hutcheson, Kate A. [Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Rosenthal, David I. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe; Gillin, Michael T. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); and others

    2016-05-01

    Purpose: A single-institution prospective study was conducted to assess disease control and toxicity of proton therapy for patients with head and neck cancer. Methods and Materials: Disease control, toxicity, functional outcomes, and patterns of failure for the initial cohort of patients with oropharyngeal squamous carcinoma (OPC) treated with intensity modulated proton therapy (IMPT) were prospectively collected in 2 registry studies at a single institution. Locoregional failures were analyzed by using deformable image registration. Results: Fifty patients with OPC treated from March 3, 2011, to July 2014 formed the cohort. Eighty-four percent were male, 50% had never smoked, 98% had stage III/IV disease, 64% received concurrent therapy, and 35% received induction chemotherapy. Forty-four of 45 tumors (98%) tested for p16 were positive. All patients received IMPT (multifield optimization to n=46; single-field optimization to n=4). No Common Terminology Criteria for Adverse Events grade 4 or 5 toxicities were observed. The most common grade 3 toxicities were acute mucositis in 58% of patients and late dysphagia in 12%. Eleven patients had a gastrostomy (feeding) tube placed during therapy, but none had a feeding tube at last follow-up. At a median follow-up time of 29 months, 5 patients had disease recurrence: local in 1, local and regional in 1, regional in 2, and distant in 1. The 2-year actuarial overall and progression-free survival rates were 94.5% and 88.6%. Conclusions: The oncologic, toxicity, and functional outcomes after IMPT for OPC are encouraging and provide the basis for ongoing and future clinical studies.

  7. Intensity-modulated radiation therapy: not a dry eye in the house

    International Nuclear Information System (INIS)

    Arnold, Anthony; Arnold, Belinda; Capp, Anne; Fox, Chris; Metcalfe, Peter; Chapman, Alison; Tangboonduangjit, Puangpeng

    2004-01-01

    Inverse planned intensity-modulated radiation therapy (IMRT) has been applied to patients in a conformal fashion in order to avoid the lacrimal gland. In the present study, we report a patient in which a potential planned dose of 63 Gy to the lacrimal gland for a conventional plan was reduced to 12 Gy to the lacrimal gland for the IMRT plan. Dose objective inverse planning was provided using a Pinnacle treatment planning computer and treatment was delivered using a Varian dynamic multileaf collimator (MLC) on a Varian linear accelerator. Because multiple MLC segments are used to deliver the modulated treatment, conventional dose checks by manual calculation are not practical. To aid in an alternative dosimetric verification process, the Pinnacle planning computer has two unique dose tools, which provide axial and beams eye view doses on user-specified check phantoms. The combined field axial dose tool matched our ion chamber dose checks within ± 2.4% at the isocentre. The individual beams eye view dose tool matched film dose maps within ± 3% in the umbra Copyright (2004) Blackwell Publishing Asia Pty Ltd

  8. Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System

    Energy Technology Data Exchange (ETDEWEB)

    Rankine, Leith J., E-mail: Leith_Rankine@med.unc.edu [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Department of Radiation Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Mein, Stewart [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Cai, Bin; Curcuru, Austen [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Juang, Titania; Miles, Devin [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Mutic, Sasa; Wang, Yuhe [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Oldham, Mark [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Li, H. Harold, E-mail: hli@radonc.wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States)

    2017-04-01

    Purpose: To validate the dosimetric accuracy of a commercially available magnetic resonance guided intensity modulated radiation therapy (MRgIMRT) system using a hybrid approach: 3-dimensional (3D) measurements and Monte Carlo calculations. Methods and Materials: We used PRESAGE radiochromic plastic dosimeters with remote optical computed tomography readout to perform 3D high-resolution measurements, following a novel remote dosimetry protocol. We followed the intensity modulated radiation therapy commissioning recommendations of American Association of Physicists in Medicine Task Group 119, adapted to incorporate 3D data. Preliminary tests (“AP” and “3D-Bands”) were delivered to 9.5-cm usable diameter cylindrical PRESAGE dosimeters to validate the treatment planning system (TPS) for nonmodulated deliveries; assess the sensitivity, uniformity, and rotational symmetry of the PRESAGE dosimeters; and test the robustness of the remote dosimetry protocol. Following this, 4 clinical MRgIMRT plans (“MultiTarget,” “Prostate,” “Head/Neck,” and “C-Shape”) were measured using 13-cm usable diameter PRESAGE dosimeters. For all plans, 3D-γ (3% or 3 mm global, 10% threshold) passing rates were calculated and 3D-γ maps were examined. Point doses were measured with an IBA-CC01 ionization chamber for validation of absolute dose. Finally, by use of an in-house-developed, GPU-accelerated Monte Carlo algorithm (gPENELOPE), we independently calculated dose for all 6 Task Group 119 plans and compared against the TPS. Results: For PRESAGE measurements, 3D-γ analysis yielded passing rates of 98.7%, 99.2%, 98.5%, 98.0%, 99.2%, and 90.7% for AP, 3D-Bands, MultiTarget, Prostate, Head/Neck, and C-Shape, respectively. Ion chamber measurements were within an average of 0.5% (±1.1%) from the TPS dose. Monte Carlo calculations demonstrated good agreement with the TPS, with a mean 3D-γ passing rate of 98.5% ± 1.9% using a stricter 2%/2-mm criterion. Conclusions: We

  9. Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System

    International Nuclear Information System (INIS)

    Rankine, Leith J.; Mein, Stewart; Cai, Bin; Curcuru, Austen; Juang, Titania; Miles, Devin; Mutic, Sasa; Wang, Yuhe; Oldham, Mark; Li, H. Harold

    2017-01-01

    Purpose: To validate the dosimetric accuracy of a commercially available magnetic resonance guided intensity modulated radiation therapy (MRgIMRT) system using a hybrid approach: 3-dimensional (3D) measurements and Monte Carlo calculations. Methods and Materials: We used PRESAGE radiochromic plastic dosimeters with remote optical computed tomography readout to perform 3D high-resolution measurements, following a novel remote dosimetry protocol. We followed the intensity modulated radiation therapy commissioning recommendations of American Association of Physicists in Medicine Task Group 119, adapted to incorporate 3D data. Preliminary tests (“AP” and “3D-Bands”) were delivered to 9.5-cm usable diameter cylindrical PRESAGE dosimeters to validate the treatment planning system (TPS) for nonmodulated deliveries; assess the sensitivity, uniformity, and rotational symmetry of the PRESAGE dosimeters; and test the robustness of the remote dosimetry protocol. Following this, 4 clinical MRgIMRT plans (“MultiTarget,” “Prostate,” “Head/Neck,” and “C-Shape”) were measured using 13-cm usable diameter PRESAGE dosimeters. For all plans, 3D-γ (3% or 3 mm global, 10% threshold) passing rates were calculated and 3D-γ maps were examined. Point doses were measured with an IBA-CC01 ionization chamber for validation of absolute dose. Finally, by use of an in-house-developed, GPU-accelerated Monte Carlo algorithm (gPENELOPE), we independently calculated dose for all 6 Task Group 119 plans and compared against the TPS. Results: For PRESAGE measurements, 3D-γ analysis yielded passing rates of 98.7%, 99.2%, 98.5%, 98.0%, 99.2%, and 90.7% for AP, 3D-Bands, MultiTarget, Prostate, Head/Neck, and C-Shape, respectively. Ion chamber measurements were within an average of 0.5% (±1.1%) from the TPS dose. Monte Carlo calculations demonstrated good agreement with the TPS, with a mean 3D-γ passing rate of 98.5% ± 1.9% using a stricter 2%/2-mm criterion. Conclusions: We

  10. Improved Beam Angle Arrangement in Intensity Modulated Proton Therapy Treatment Planning for Localized Prostate Cancer

    International Nuclear Information System (INIS)

    Cao, Wenhua; Lim, Gino J.; Li, Yupeng; Zhu, X. Ronald; Zhang, Xiaodong

    2015-01-01

    Purpose: This study investigates potential gains of an improved beam angle arrangement compared to a conventional fixed gantry setup in intensity modulated proton therapy (IMPT) treatment for localized prostate cancer patients based on a proof of principle study. Materials and Methods: Three patients with localized prostate cancer retrospectively selected from our institution were studied. For each patient, IMPT plans were designed using two, three and four beam angles, respectively, obtained from a beam angle optimization algorithm. Those plans were then compared with ones using two lateral parallel-opposed beams according to the conventional planning protocol for localized prostate cancer adopted at our institution. Results: IMPT plans with two optimized angles achieved significant improvements in rectum sparing and moderate improvements in bladder sparing against those with two lateral angles. Plans with three optimized angles further improved rectum sparing significantly over those two-angle plans, whereas four-angle plans found no advantage over three-angle plans. A possible three-beam class solution for localized prostate patients was suggested and demonstrated with preserved dosimetric benefits because individually optimized three-angle solutions were found sharing a very similar pattern. Conclusions: This study has demonstrated the potential of using an improved beam angle arrangement to better exploit the theoretical dosimetric benefits of proton therapy and provided insights of selecting quality beam angles for localized prostate cancer treatment

  11. Australia-wide comparison of intensity modulated radiation therapy prostate plans

    International Nuclear Information System (INIS)

    Skala, M.; Holloway, L.; Bailey, M.; Kneebone, A.

    2005-01-01

    The aim of this study was to investigate the ability of Australian centres to produce high-dose intensity modulated radiation therapy (IMRT) prostate plans, and to compare the planning parameters and resultant dose distributions. Five Australian radiation therapy departments were invited to participate. Each centre received an identical 5 mm-slice CT data set complete with contours of the prostate, seminal vesicles, rectum, bladder, femoral heads and body outline. The planning team was asked to produce the best plan possible, using published Memorial Sloan-Kettering Cancer Centre prescription and dose constraints. Three centres submitted plans for evaluation. All plans covered the planning target volume adequately; however, only one plan met all the critical organ dose constraints. Although the planning parameters, beam arrangements and planning systems were different for each centre, the resulting plans were similar. In Australia, IMRT for prostate cancer is in the early stages of implementation, with routine use limited to a few centres. Copyright (2005) Blackwell Science Pty Ltd

  12. Statistical process control analysis for patient quality assurance of intensity modulated radiation therapy

    Science.gov (United States)

    Lee, Rena; Kim, Kyubo; Cho, Samju; Lim, Sangwook; Lee, Suk; Shim, Jang Bo; Huh, Hyun Do; Lee, Sang Hoon; Ahn, Sohyun

    2017-11-01

    This study applied statistical process control to set and verify the quality assurances (QA) tolerance standard for our hospital's characteristics with the criteria standards that are applied to all the treatment sites with this analysis. Gamma test factor of delivery quality assurances (DQA) was based on 3%/3 mm. Head and neck, breast, prostate cases of intensity modulated radiation therapy (IMRT) or volumetric arc radiation therapy (VMAT) were selected for the analysis of the QA treatment sites. The numbers of data used in the analysis were 73 and 68 for head and neck patients. Prostate and breast were 49 and 152 by MapCHECK and ArcCHECK respectively. C p value of head and neck and prostate QA were above 1.0, C pml is 1.53 and 1.71 respectively, which is close to the target value of 100%. C pml value of breast (IMRT) was 1.67, data values are close to the target value of 95%. But value of was 0.90, which means that the data values are widely distributed. C p and C pml of breast VMAT QA were respectively 1.07 and 2.10. This suggests that the VMAT QA has better process capability than the IMRT QA. Consequently, we should pay more attention to planning and QA before treatment for breast Radiotherapy.

  13. Multicentre quality assurance of intensity-modulated radiation therapy plans: a precursor to clinical trials

    International Nuclear Information System (INIS)

    Williams, M. J.; Bailey, M. J.; Forstner, D.; Metcalfe, P. E

    2007-01-01

    Full text: A multicentre planning study comparing intensity-modulated radiation therapy (IMRT) plans for the treatment of a head and neck cancer has been carried out. Three Australian radiotherapy centres, each with a different planning system, were supplied a fully contoured CT dataset and requested to generate an IMRT plan in accordance with the requirements of an IMRT-based radiation therapy oncology group clinical trial. Plan analysis was carried out using software developed specifically for reviewing multicentre clinical trial data. Two out of the three plans failed to meet the prescription requirements with one misinterpreting the prescription and the third failed to meet one of the constraints. Only one plan achieved all of the dose objectives for the critical structures and normal tissues. Although each centre used very similar planning parameters and beam arrangements the resulting plans were quite different. The subjective interpretation and application of the prescription and planning objectives emphasize one of the many difficulties in carrying out multicentre IMRT planning studies. The treatment prescription protocol in a clinical trial must be both lucid and unequivocally stated to avoid misinterpretation. Australian radiotherapy centres must show that they can produce a quality IMRT plan and that they can adhere to protocols for IMRT planning before using it in a clinical trial

  14. Direct-aperture optimization applied to selection of beam orientations in intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Bedford, J L; Webb, S

    2007-01-01

    Direct-aperture optimization (DAO) was applied to iterative beam-orientation selection in intensity-modulated radiation therapy (IMRT), so as to ensure a realistic segmental treatment plan at each iteration. Nested optimization engines dealt separately with gantry angles, couch angles, collimator angles, segment shapes, segment weights and wedge angles. Each optimization engine performed a random search with successively narrowing step sizes. For optimization of segment shapes, the filtered backprojection (FBP) method was first used to determine desired fluence, the fluence map was segmented, and then constrained direct-aperture optimization was used thereafter. Segment shapes were fully optimized when a beam angle was perturbed, and minimally re-optimized otherwise. The algorithm was compared with a previously reported method using FBP alone at each orientation iteration. An example case consisting of a cylindrical phantom with a hemi-annular planning target volume (PTV) showed that for three-field plans, the method performed better than when using FBP alone, but for five or more fields, neither method provided much benefit over equally spaced beams. For a prostate case, improved bladder sparing was achieved through the use of the new algorithm. A plan for partial scalp treatment showed slightly improved PTV coverage and lower irradiated volume of brain with the new method compared to FBP alone. It is concluded that, although the method is computationally intensive and not suitable for searching large unconstrained regions of beam space, it can be used effectively in conjunction with prior class solutions to provide individually optimized IMRT treatment plans

  15. Intensity-modulated photon arc therapy for treatment of pleural mesothelioma

    International Nuclear Information System (INIS)

    Tobler, Matt; Watson, Gordon; Leavitt, Dennis

    2002-01-01

    Radiotherapy plays a key role in the definitive or adjuvant management of patients with mesothelioma of the pleural surface. Many patients are referred for radiation with intact lung following biopsy or subtotal pleurectomy. Delivery of efficacious doses of radiation to the pleural lining while avoiding lung parenchyma toxicity has been a difficult technical challenge. Using opposed photon fields produce doses in lung that result in moderate-to-severe pulmonary toxicity in 100% of patients treated. Combined photon-electron beam treatment, at total doses of 4250 cGy to the pleural surface, results in two-thirds of the lung volume receiving over 2100 cGy. We have developed a technique using intensity-modulated photon arc therapy (IMRT) that significantly improves the dose distribution to the pleural surface with concomitant decrease in dose to lung parenchyma compared to traditional techniques. IMRT treatment of the pleural lining consists of segments of photon arcs that can be intensity modulated with varying beam weights and multileaf positions to produce a more uniform distribution to the pleural surface, while at the same time reducing the overall dose to the lung itself. Computed tomography (CT) simulation is critical for precise identification of target volumes as well as critical normal structures (lung and heart). Rotational arc trajectories and individual leaf positions and weightings are then defined for each CT plane within the patient. This paper will describe the proposed rotational IMRT technique and, using simulated isodose distributions, show the improved potential for sparing of dose to the critical structures of the lung, heart, and spinal cord

  16. Stereotactic body radiation therapy planning with duodenal sparing using volumetric-modulated arc therapy vs intensity-modulated radiation therapy in locally advanced pancreatic cancer: A dosimetric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rachit; Wild, Aaron T.; Ziegler, Mark A.; Hooker, Ted K.; Dah, Samson D.; Tran, Phuoc T.; Kang, Jun; Smith, Koren; Zeng, Jing [Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Hospital, 401N. Broadway, Weinberg Suite 1440, Baltimore, MD 21231 (United States); Pawlik, Timothy M. [Department of Surgery, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Tryggestad, Erik [Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Hospital, 401N. Broadway, Weinberg Suite 1440, Baltimore, MD 21231 (United States); Ford, Eric [Department of Radiation Oncology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA (United States); Herman, Joseph M., E-mail: jherma15@jhmi.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Hospital, 401N. Broadway, Weinberg Suite 1440, Baltimore, MD 21231 (United States)

    2013-10-01

    Stereotactic body radiation therapy (SBRT) achieves excellent local control for locally advanced pancreatic cancer (LAPC), but may increase late duodenal toxicity. Volumetric-modulated arc therapy (VMAT) delivers intensity-modulated radiation therapy (IMRT) with a rotating gantry rather than multiple fixed beams. This study dosimetrically evaluates the feasibility of implementing duodenal constraints for SBRT using VMAT vs IMRT. Non–duodenal sparing (NS) and duodenal-sparing (DS) VMAT and IMRT plans delivering 25 Gy in 1 fraction were generated for 15 patients with LAPC. DS plans were constrained to duodenal D{sub max} of<30 Gy at any point. VMAT used 1 360° coplanar arc with 4° spacing between control points, whereas IMRT used 9 coplanar beams with fixed gantry positions at 40° angles. Dosimetric parameters for target volumes and organs at risk were compared for DS planning vs NS planning and VMAT vs IMRT using paired-sample Wilcoxon signed rank tests. Both DS VMAT and DS IMRT achieved significantly reduced duodenal D{sub mean}, D{sub max}, D{sub 1cc}, D{sub 4%}, and V{sub 20} {sub Gy} compared with NS plans (all p≤0.002). DS constraints compromised target coverage for IMRT as demonstrated by reduced V{sub 95%} (p = 0.01) and D{sub mean} (p = 0.02), but not for VMAT. DS constraints resulted in increased dose to right kidney, spinal cord, stomach, and liver for VMAT. Direct comparison of DS VMAT and DS IMRT revealed that VMAT was superior in sparing the left kidney (p<0.001) and the spinal cord (p<0.001), whereas IMRT was superior in sparing the stomach (p = 0.05) and the liver (p = 0.003). DS VMAT required 21% fewer monitor units (p<0.001) and delivered treatment 2.4 minutes faster (p<0.001) than DS IMRT. Implementing DS constraints during SBRT planning for LAPC can significantly reduce duodenal point or volumetric dose parameters for both VMAT and IMRT. The primary consequence of implementing DS constraints for VMAT is increased dose to other organs at

  17. Comparative analysis of volumetric-modulated arc therapy and intensity-modulated radiotherapy for base of tongue cancer

    International Nuclear Information System (INIS)

    Nithya, L.; Arulraj, Kumar; Rathinamuthu, Sasikumar; Pandey, Manish Bhushan; Nambi Raj, N. Arunai

    2014-01-01

    The aim of this study was to compare the various dosimetric parameters of dynamic multileaf collimator (MLC) intensity modulated radiation therapy (IMRT) plans with volumetric modulated arc therapy (VMAT) plans for base of tongue cases. All plans were done in Monaco planning system for Elekta synergy linear accelerator with 80 MLC. IMRT plans were planned with nine stationary beams, and VMAT plans were done for 360° arc with single arc or dual arc. The dose to the planning target volumes (PTV) for 70, 63, and 56 Gy was compared. The dose to 95, 98, and 50% volume of PTV were analyzed. The homogeneity index (HI) and the conformity index (CI) of the PTV 70 were also analyzed. IMRT and VMAT plan showed similar dose coverage, HI, and CI. Maximum dose and dose to 1-cc volume of spinal cord, planning risk volume (PRV) cord, and brain stem were compared. IMRT plan and VMAT plan showed similar results except for the 1 cc of PRV cord that received slightly higher dose in VMAT plan. Mean dose and dose to 50% volume of right and left parotid glands were analyzed. VMAT plan gave better sparing of parotid glands than IMRT. In normal tissue dose analyses VMAT was better than IMRT. The number of monitor units (MU) required for delivering the good quality of the plan and the time required to deliver the plan for IMRT and VMAT were compared. The number of MUs for VMAT was higher than that of IMRT plans. However, the delivery time was reduced by a factor of two for VMAT compared with IMRT. VMAT plans yielded good quality of the plan compared with IMRT, resulting in reduced treatment time and improved efficiency for base of tongue cases. (author)

  18. Comparative analysis of volumetric-modulated arc therapy and intensity-modulated radiotherapy for base of tongue cancer

    Directory of Open Access Journals (Sweden)

    L Nithya

    2014-01-01

    Full Text Available The aim of this study was to compare the various dosimetric parameters of dynamic multileaf collimator (MLC intensity modulated radiation therapy (IMRT plans with volumetric modulated arc therapy (VMAT plans for base of tongue cases. All plans were done in Monaco planning system for Elekta synergy linear accelerator with 80 MLC. IMRT plans were planned with nine stationary beams, and VMAT plans were done for 360° arc with single arc or dual arc. The dose to the planning target volumes (PTV for 70, 63, and 56 Gy was compared. The dose to 95, 98, and 50% volume of PTV were analyzed. The homogeneity index (HI and the conformity index (CI of the PTV 70 were also analyzed. IMRT and VMAT plan showed similar dose coverage, HI, and CI. Maximum dose and dose to 1-cc volume of spinal cord, planning risk volume (PRV cord, and brain stem were compared. IMRT plan and VMAT plan showed similar results except for the 1 cc of PRV cord that received slightly higher dose in VMAT plan. Mean dose and dose to 50% volume of right and left parotid glands were analyzed. VMAT plan gave better sparing of parotid glands than IMRT. In normal tissue dose analyses VMAT was better than IMRT. The number of monitor units (MU required for delivering the good quality of the plan and the time required to deliver the plan for IMRT and VMAT were compared. The number of MUs for VMAT was higher than that of IMRT plans. However, the delivery time was reduced by a factor of two for VMAT compared with IMRT. VMAT plans yielded good quality of the plan compared with IMRT, resulting in reduced treatment time and improved efficiency for base of tongue cases.

  19. Introducing an on-line adaptive procedure for prostate image guided intensity modulate proton therapy.

    Science.gov (United States)

    Zhang, M; Westerly, D C; Mackie, T R

    2011-08-07

    With on-line image guidance (IG), prostate shifts relative to the bony anatomy can be corrected by realigning the patient with respect to the treatment fields. In image guided intensity modulated proton therapy (IG-IMPT), because the proton range is more sensitive to the material it travels through, the realignment may introduce large dose variations. This effect is studied in this work and an on-line adaptive procedure is proposed to restore the planned dose to the target. A 2D anthropomorphic phantom was constructed from a real prostate patient's CT image. Two-field laterally opposing spot 3D-modulation and 24-field full arc distal edge tracking (DET) plans were generated with a prescription of 70 Gy to the planning target volume. For the simulated delivery, we considered two types of procedures: the non-adaptive procedure and the on-line adaptive procedure. In the non-adaptive procedure, only patient realignment to match the prostate location in the planning CT was performed. In the on-line adaptive procedure, on top of the patient realignment, the kinetic energy for each individual proton pencil beam was re-determined from the on-line CT image acquired after the realignment and subsequently used for delivery. Dose distributions were re-calculated for individual fractions for different plans and different delivery procedures. The results show, without adaptive, that both the 3D-modulation and the DET plans experienced delivered dose degradation by having large cold or hot spots in the prostate. The DET plan had worse dose degradation than the 3D-modulation plan. The adaptive procedure effectively restored the planned dose distribution in the DET plan, with delivered prostate D(98%), D(50%) and D(2%) values less than 1% from the prescription. In the 3D-modulation plan, in certain cases the adaptive procedure was not effective to reduce the delivered dose degradation and yield similar results as the non-adaptive procedure. In conclusion, based on this 2D phantom

  20. Predictors of Hypothyroidism in Hodgkin Lymphoma Survivors After Intensity Modulated Versus 3-Dimensional Radiation Therapy.

    Science.gov (United States)

    Pinnix, Chelsea C; Cella, Laura; Andraos, Therese Y; Ayoub, Zeina; Milgrom, Sarah A; Gunther, Jillian; Thosani, Sonali; Wogan, Christine; Conson, Manuel; D'Avino, Vittoria; Oki, Yasuhiro; Fanale, Michelle; Lee, Hun J; Neelapu, Sattva; Fayad, Luis; Hagemeister, Frederick; Rodriguez, M Alma; Nastoupil, Loretta J; Nieto, Yago; Qiao, Wei; Pacelli, Roberto; Dabaja, Bouthaina

    2018-03-14

    To identify predictors of hypothyroidism after chemoradiation therapy for Hodgkin lymphoma (HL) and to compare outcomes after intensity modulated radiation therapy (IMRT) with those after 3-dimensional (3D) conformal radiation therapy (CRT). Ninety patients who underwent involved-site IMRT in 2009 through 2014 were evaluated for treatment-induced hypothyroidism, defined as elevated thyroid-stimulating hormone or decreased free thyroxine levels (or both). Receiver operating characteristic curve analysis identified individuals at low versus high risk based on dosimetric variables. Dosimetric cutoff points were verified with an external data set of 50 patients who underwent 3D-CRT. In the IMRT group, most patients (75 [83%]) had stage II HL, and the median prescribed dose was 30.6 Gy; in the 3D-CRT group, 32 patients (64%) had stage II HL, and the median prescribed dose was 32.0 Gy. No differences were found in the proportions of patients with bilateral (P = .982) or unilateral (P = .074) neck involvement between the 2 groups. Hypothyroidism rates were marginally higher in the IMRT group, with estimated 3-year rates of freedom from hypothyroidism of 56.1% in the 3D-CRT group and 40% in the IMRT group (P = .057). Univariate analysis showed that smaller thyroid volume and higher thyroid dose were associated with hypothyroidism in both groups (P hypothyroidism (P = .001 and P hypothyroidism (P hypothyroidism after either IMRT or 3D-CRT for HL. IMRT may confer a higher risk than 3D-CRT unless a treatment avoidance structure is used during planning. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Intensity-Modulated Radiation Therapy With Concurrent Chemotherapy as Preoperative Treatment for Localized Gastric Adenocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Chakravarty, Twisha; Crane, Christopher H. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Ajani, Jaffer A. [Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Mansfield, Paul F. [Department of Surgical Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Briere, Tina M.; Beddar, A. Sam [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Mok, Henry; Reed, Valerie K.; Krishnan, Sunil; Delclos, Marc E. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Das, Prajnan, E-mail: PrajDas@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2012-06-01

    Purpose: The goal of this study was to evaluate dosimetric parameters, acute toxicity, pathologic response, and local control in patients treated with preoperative intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy for localized gastric adenocarcinoma. Methods: Between November 2007 and April 2010, 25 patients with localized gastric adenocarcinoma were treated with induction chemotherapy, followed by preoperative IMRT and concurrent chemotherapy and, finally, surgical resection. The median radiation therapy dose was 45 Gy. Concurrent chemotherapy was 5-fluorouracil and oxaliplatin in 18 patients, capecitabine in 3, and other regimens in 4. Subsequently, resection was performed with total gastrectomy in 13 patients, subtotal gastrectomy in 7, and other surgeries in 5. Results: Target coverage, expressed as the ratio of the minimum dose received by 99% of the planning target volume to the prescribed dose, was a median of 0.97 (range, 0.92-1.01). The median V{sub 30} (percentage of volume receiving at least 30 Gy) for the liver was 26%; the median V{sub 20} (percentage of volume receiving at least 20 Gy) for the right and left kidneys was 14% and 24%, respectively; and the median V{sub 40} (percentage of volume receiving at least 40 Gy) for the heart was 18%. Grade 3 acute toxicity developed in 14 patients (56%), including dehydration in 10, nausea in 8, and anorexia in 5. Grade 4 acute toxicity did not develop in any patient. There were no significant differences in the rates of acute toxicity, hospitalization, or feeding tube use in comparison to those in a group of 50 patients treated with preoperative three-dimensional conformal radiation therapy with concurrent chemotherapy. R0 resection was obtained in 20 patients (80%), and pathologic complete response occurred in 5 (20%). Conclusions: Preoperative IMRT for gastric adenocarcinoma was well tolerated, accomplished excellent target coverage and normal structure sparing, and led to appropriate

  2. Intensity-Modulated Radiation Therapy With Concurrent Chemotherapy as Preoperative Treatment for Localized Gastric Adenocarcinoma

    International Nuclear Information System (INIS)

    Chakravarty, Twisha; Crane, Christopher H.; Ajani, Jaffer A.; Mansfield, Paul F.; Briere, Tina M.; Beddar, A. Sam; Mok, Henry; Reed, Valerie K.; Krishnan, Sunil; Delclos, Marc E.; Das, Prajnan

    2012-01-01

    Purpose: The goal of this study was to evaluate dosimetric parameters, acute toxicity, pathologic response, and local control in patients treated with preoperative intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy for localized gastric adenocarcinoma. Methods: Between November 2007 and April 2010, 25 patients with localized gastric adenocarcinoma were treated with induction chemotherapy, followed by preoperative IMRT and concurrent chemotherapy and, finally, surgical resection. The median radiation therapy dose was 45 Gy. Concurrent chemotherapy was 5-fluorouracil and oxaliplatin in 18 patients, capecitabine in 3, and other regimens in 4. Subsequently, resection was performed with total gastrectomy in 13 patients, subtotal gastrectomy in 7, and other surgeries in 5. Results: Target coverage, expressed as the ratio of the minimum dose received by 99% of the planning target volume to the prescribed dose, was a median of 0.97 (range, 0.92–1.01). The median V 30 (percentage of volume receiving at least 30 Gy) for the liver was 26%; the median V 20 (percentage of volume receiving at least 20 Gy) for the right and left kidneys was 14% and 24%, respectively; and the median V 40 (percentage of volume receiving at least 40 Gy) for the heart was 18%. Grade 3 acute toxicity developed in 14 patients (56%), including dehydration in 10, nausea in 8, and anorexia in 5. Grade 4 acute toxicity did not develop in any patient. There were no significant differences in the rates of acute toxicity, hospitalization, or feeding tube use in comparison to those in a group of 50 patients treated with preoperative three-dimensional conformal radiation therapy with concurrent chemotherapy. R0 resection was obtained in 20 patients (80%), and pathologic complete response occurred in 5 (20%). Conclusions: Preoperative IMRT for gastric adenocarcinoma was well tolerated, accomplished excellent target coverage and normal structure sparing, and led to appropriate pathologic

  3. Acute Esophagus Toxicity in Lung Cancer Patients After Intensity Modulated Radiation Therapy and Concurrent Chemotherapy

    International Nuclear Information System (INIS)

    Kwint, Margriet; Uyterlinde, Wilma; Nijkamp, Jasper; Chen, Chun; Bois, Josien de; Sonke, Jan-Jakob; Heuvel, Michel van den; Knegjens, Joost; Herk, Marcel van; Belderbos, José

    2012-01-01

    Purpose: The purpose of this study was to investigate the dose-effect relation between acute esophageal toxicity (AET) and the dose-volume parameters of the esophagus after intensity modulated radiation therapy (IMRT) and concurrent chemotherapy for patients with non-small cell lung cancer (NSCLC). Patients and Methods: One hundred thirty-nine patients with inoperable NSCLC treated with IMRT and concurrent chemotherapy were prospectively analyzed. The fractionation scheme was 66 Gy in 24 fractions. All patients received concurrently a daily dose of cisplatin (6 mg/m²). Maximum AET was scored according to Common Toxicity Criteria 3.0. Dose-volume parameters V5 to V70, D mean and D max of the esophagus were calculated. A logistic regression analysis was performed to analyze the dose-effect relation between these parameters and grade ≥2 and grade ≥3 AET. The outcome was compared with the clinically used esophagus V35 prediction model for grade ≥2 after radical 3-dimensional conformal radiation therapy (3DCRT) treatment. Results: In our patient group, 9% did not experience AET, and 31% experienced grade 1 AET, 38% grade 2 AET, and 22% grade 3 AET. The incidence of grade 2 and grade 3 AET was not different from that in patients treated with CCRT using 3DCRT. The V50 turned out to be the most significant dosimetric predictor for grade ≥3 AET (P=.012). The derived V50 model was shown to predict grade ≥2 AET significantly better than the clinical V35 model (P<.001). Conclusions: For NSCLC patients treated with IMRT and concurrent chemotherapy, the V50 was identified as most accurate predictor of grade ≥3 AET. There was no difference in the incidence of grade ≥2 AET between 3DCRT and IMRT in patients treated with concurrent chemoradiation therapy.

  4. Intensity-modulated radiation therapy for pediatric medulloblastoma: early report on the reduction of ototoxicity

    International Nuclear Information System (INIS)

    Huang, Eugene; Teh, Bin S.; Strother, Douglas R.; Davis, Quillin G.; Chiu, J. Kam; Lu, Hsin H.; Carpenter, L. Steven; Mai Weiyuan; Chintagumpala, Murali M.; South, Michael; Grant, Walter H. III; Butler, E. Brian; Woo, Shiao Y.

    2002-01-01

    Purpose: The combination of cisplatin chemotherapy and radiation therapy for the treatment of medulloblastoma has been shown to cause significant ototoxicity, impairing a child's cognitive function and quality of life. Our purpose is to determine whether the new conformal technique of intensity-modulated radiation therapy (IMRT) can achieve lower rates of hearing loss by decreasing the radiation dose delivered to the cochlea and eighth cranial nerve (auditory apparatus). Patients and Methods: Twenty-six pediatric patients treated for medulloblastoma were retrospectively divided into two groups that received either conventional radiotherapy (Conventional-RT Group) or IMRT (IMRT Group). One hundred thirteen pure-tone audiograms were evaluated retrospectively, and hearing function was graded on a scale of 0 to 4 according to the Pediatric Oncology Group's toxicity criteria. Statistical analysis comparing the rates of ototoxicity was performed using Fisher's exact test with two-tailed analysis. Results: When compared to conventional radiotherapy, IMRT delivered 68% of the radiation dose to the auditory apparatus (mean dose: 36.7 vs. 54.2 Gy). Audiometric evaluation showed that mean decibel hearing thresholds of the IMRT Group were lower at every frequency compared to those of the Conventional-RT Group, despite having higher cumulative doses of cisplatin. The overall incidence of ototoxicity was lower in the IMRT Group. Thirteen percent of the IMRT Group had Grade 3 or 4 hearing loss, compared to 64% of the Conventional-RT Group (p<0.014). Conclusion: The conformal technique of IMRT delivered much lower doses of radiation to the auditory apparatus, while still delivering full doses to the desired target volume. Our findings suggest that, despite higher doses of cisplatin, and despite radiotherapy before cisplatin therapy, treatment with IMRT can achieve a lower rate of hearing loss

  5. Computer-assisted selection of coplanar beam orientations in intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Pugachev, A.; Xing, L. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States)]. E-mail: lei@reyes.stanford.edu

    2001-09-01

    In intensity-modulated radiation therapy (IMRT), the incident beam orientations are often determined by a trial and error search. The conventional beam's-eye view (BEV) tool becomes less helpful in IMRT because it is frequently required that beams go through organs at risk (OARs) in order to achieve a compromise between the dosimetric objectives of the planning target volume (PTV) and the OARs. In this paper, we report a beam's-eye view dosimetrics (BEVD) technique to assist in the selection of beam orientations in IMRT. In our method, each beam portal is divided into a grid of beamlets. A score function is introduced to measure the 'goodness' of each beamlet at a given gantry angle. The score is determined by the maximum PTV dose deliverable by the beamlet without exceeding the tolerance doses of the OARs and normal tissue located in the path of the beamlet. The overall score of the gantry angle is given by a sum of the scores of all beamlets. For a given patient, the score function is evaluated for each possible beam orientation. The directions with the highest scores are then selected as the candidates for beam placement. This procedure is similar to the BEV approach used in conventional radiation therapy, except that the evaluation by a human is replaced by a score function to take into account the intensity modulation. This technique allows one to select beam orientations without the excessive computing overhead of computer optimization of beam orientation. It also provides useful insight into the problem of selection of beam orientation and is especially valuable for complicated cases where the PTV is surrounded by several sensitive structures and where it is difficult to select a set of 'good' beam orientations. Several two-dimensional (2D) model cases were used to test the proposed technique. The plans obtained using the BEVD-selected beam orientations were compared with the plans obtained using equiangular spaced beams. For

  6. SU-F-T-209: Multicriteria Optimization Algorithm for Intensity Modulated Radiation Therapy Using Pencil Proton Beam Scanning

    Energy Technology Data Exchange (ETDEWEB)

    Beltran, C; Kamal, H [Mayo Clinic, Rochester, MN (United States)

    2016-06-15

    Purpose: To provide a multicriteria optimization algorithm for intensity modulated radiation therapy using pencil proton beam scanning. Methods: Intensity modulated radiation therapy using pencil proton beam scanning requires efficient optimization algorithms to overcome the uncertainties in the Bragg peaks locations. This work is focused on optimization algorithms that are based on Monte Carlo simulation of the treatment planning and use the weights and the dose volume histogram (DVH) control points to steer toward desired plans. The proton beam treatment planning process based on single objective optimization (representing a weighted sum of multiple objectives) usually leads to time-consuming iterations involving treatment planning team members. We proved a time efficient multicriteria optimization algorithm that is developed to run on NVIDIA GPU (Graphical Processing Units) cluster. The multicriteria optimization algorithm running time benefits from up-sampling of the CT voxel size of the calculations without loss of fidelity. Results: We will present preliminary results of Multicriteria optimization for intensity modulated proton therapy based on DVH control points. The results will show optimization results of a phantom case and a brain tumor case. Conclusion: The multicriteria optimization of the intensity modulated radiation therapy using pencil proton beam scanning provides a novel tool for treatment planning. Work support by a grant from Varian Inc.

  7. SU-F-T-209: Multicriteria Optimization Algorithm for Intensity Modulated Radiation Therapy Using Pencil Proton Beam Scanning

    International Nuclear Information System (INIS)

    Beltran, C; Kamal, H

    2016-01-01

    Purpose: To provide a multicriteria optimization algorithm for intensity modulated radiation therapy using pencil proton beam scanning. Methods: Intensity modulated radiation therapy using pencil proton beam scanning requires efficient optimization algorithms to overcome the uncertainties in the Bragg peaks locations. This work is focused on optimization algorithms that are based on Monte Carlo simulation of the treatment planning and use the weights and the dose volume histogram (DVH) control points to steer toward desired plans. The proton beam treatment planning process based on single objective optimization (representing a weighted sum of multiple objectives) usually leads to time-consuming iterations involving treatment planning team members. We proved a time efficient multicriteria optimization algorithm that is developed to run on NVIDIA GPU (Graphical Processing Units) cluster. The multicriteria optimization algorithm running time benefits from up-sampling of the CT voxel size of the calculations without loss of fidelity. Results: We will present preliminary results of Multicriteria optimization for intensity modulated proton therapy based on DVH control points. The results will show optimization results of a phantom case and a brain tumor case. Conclusion: The multicriteria optimization of the intensity modulated radiation therapy using pencil proton beam scanning provides a novel tool for treatment planning. Work support by a grant from Varian Inc.

  8. 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.

  9. Beyond bixels: Generalizing the optimization parameters for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Markman, Jerry; Low, Daniel A.; Beavis, Andrew W.; Deasy, Joseph O.

    2002-01-01

    Intensity modulated radiation therapy (IMRT) treatment planning systems optimize fluence distributions by subdividing the fluence distribution into rectangular bixels. The algorithms typically optimize the fluence intensity directly, often leading to fluence distributions with sharp discontinuities. These discontinuities may yield difficulties in delivery of the fluence distribution, leading to inaccurate dose delivery. We have developed a method for decoupling the bixel intensities from the optimization parameters; either by introducing optimization control points from which the bixel intensities are interpolated or by parametrizing the fluence distribution using basis functions. In either case, the number of optimization search parameters is reduced from the direct bixel optimization method. To illustrate the concept, the technique is applied to two-dimensional idealized head and neck treatment plans. The interpolation algorithms investigated were nearest-neighbor, linear and cubic spline, and radial basis functions serve as the basis function test. The interpolation and basis function optimization techniques were compared against the direct bixel calculation. The number of optimization parameters were significantly reduced relative to the bixel optimization, and this was evident in the reduction of computation time of as much as 58% from the full bixel optimization. The dose distributions obtained using the reduced optimization parameter sets were very similar to the full bixel optimization when examined by dose distributions, statistics, and dose-volume histograms. To evaluate the sensitivity of the fluence calculations to spatial misalignment caused either by delivery errors or patient motion, the doses were recomputed with a 1 mm shift in each beam and compared to the unshifted distributions. Except for the nearest-neighbor algorithm, the reduced optimization parameter dose distributions were generally less sensitive to spatial shifts than the bixel

  10. Comparison of dose-volume histograms for Tomo therapy, linear accelerator-based 3D conformal radiation therapy, and intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Ji, Youn-Sang; Dong, Kyung-Rae; Kim, Chang-Bok; Choi, Seong-Kwan; Chung, Woon-Kwan; Lee, Jong-Woong

    2011-01-01

    Highlights: → Evaluation of DVH from 3D CRT, IMRT and Tomo therapy was conducted for tumor therapy. → The doses of GTV and CTV were compared using DVHs from 3D CRT, IMRT and Tomo therapy. → The GTV was higher when Tomo therapy was used, while the doses of critical organ were low. → They said that Tomo therapy satisfied the goal of radiation therapy more than the others. - Abstract: Evaluation of dose-volume histograms from three-dimensional conformal radiation therapy (3D CRT), intensity-modulated radiation therapy (IMRT), and Tomo therapy was conducted. These three modalities are among the diverse treatment systems available for tumor therapy. Three patients who received tumor therapy for a malignant oligodendroglioma in the cranium, nasopharyngeal carcinoma in the cervical neck, and prostate cancer in the pelvis were selected as study subjects. Therapy plans were made for the three patients before dose-volume histograms were obtained. The doses of the gross tumor volume (GTV) and the clinical target volume (CTV) were compared using the dose-volume histograms obtained from the LINAC-based 3D CRT, IMRT planning station (Varian Eclipse-Varian, version 8.1), and Tomo therapy planning station. In addition, the doses of critical organs in the cranium, cervix, and pelvis that should be protected were compared. The GTV was higher when Tomo therapy was used compared to 3D CRT and the LINAC-based IMRT, while the doses of critical organ tissues that required protection were low. These results demonstrated that Tomo therapy satisfied the ultimate goal of radiation therapy more than the other therapies.

  11. Adjuvant intensity-modulated proton therapy in malignant pleural mesothelioma. A comparison with intensity-modulated radiotherapy and a spot size variation assessment

    Energy Technology Data Exchange (ETDEWEB)

    Lorentini, S. [Agenzia Provinciale per la Protonterapia (ATreP), Trento (Italy); Padova Univ. (Italy). Medical Physics School; Amichetti, M.; Fellin, F.; Schwarz, M. [Agenzia Provinciale per la Protonterapia (ATreP), Trento (Italy); Spiazzi, L. [Brescia Hospital (Italy). Medical Physics Dept.; Tonoli, S.; Magrini, S.M. [Brescia Hospital (Italy). Radiation Oncology Dept.

    2012-03-15

    Intensity-modulated radiation therapy (IMRT) is the state-of-the-art treatment for patients with malignant pleural mesothelioma (MPM). The goal of this work was to assess whether intensity-modulated proton therapy (IMPT) could further improve the dosimetric results allowed by IMRT. We re-planned 7 MPM cases using both photons and protons, by carrying out IMRT and IMPT plans. For both techniques, conventional dose comparisons and normal tissue complication probability (NTCP) analysis were performed. In 3 cases, additional IMPT plans were generated with different beam dimensions. IMPT allowed a slight improvement in target coverage and clear advantages in dose conformity (p < 0.001) and dose homogeneity (p = 0.01). Better organ at risk (OAR) sparing was obtained with IMPT, in particular for the liver (D{sub mean} reduction of 9.5 Gy, p = 0.001) and ipsilateral kidney (V{sub 20} reduction of 58%, p = 0.001), together with a very large reduction of mean dose for the contralateral lung (0.2 Gy vs 6.1 Gy, p = 0.0001). NTCP values for the liver showed a systematic superiority of IMPT with respect to IMRT for both the esophagus (average NTCP 14% vs. 30.5%) and the ipsilateral kidney (p = 0.001). Concerning plans obtained with different spot dimensions, a slight loss of target coverage was observed along with sigma increase, while maintaining OAR irradiation always under planning constraints. Results suggest that IMPT allows better OAR sparing with respect to IMRT, mainly for the liver, ipsilateral kidney, and contralateral lung. The use of a spot dimension larger than 3 x 3 mm (up to 9 x 9 mm) does not compromise dosimetric results and allows a shorter delivery time.

  12. 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

  13. 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)

    International Nuclear Information System (INIS)

    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

    2014-01-01

    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 18 Gy ), stomach (mean and V 20 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 18 Gy ), liver (mean dose), total bowel (V 20 Gy and mean dose), and small bowel (V 15 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 escalation and combining with radiosensitizing

  14. An Ensemble Approach to Knowledge-Based Intensity-Modulated Radiation Therapy Planning

    Directory of Open Access Journals (Sweden)

    Jiahan Zhang

    2018-03-01

    Full Text Available Knowledge-based planning (KBP utilizes experienced planners’ knowledge embedded in prior plans to estimate optimal achievable dose volume histogram (DVH of new cases. In the regression-based KBP framework, previously planned patients’ anatomical features and DVHs are extracted, and prior knowledge is summarized as the regression coefficients that transform features to organ-at-risk DVH predictions. In our study, we find that in different settings, different regression methods work better. To improve the robustness of KBP models, we propose an ensemble method that combines the strengths of various linear regression models, including stepwise, lasso, elastic net, and ridge regression. In the ensemble approach, we first obtain individual model prediction metadata using in-training-set leave-one-out cross validation. A constrained optimization is subsequently performed to decide individual model weights. The metadata is also used to filter out impactful training set outliers. We evaluate our method on a fresh set of retrospectively retrieved anonymized prostate intensity-modulated radiation therapy (IMRT cases and head and neck IMRT cases. The proposed approach is more robust against small training set size, wrongly labeled cases, and dosimetric inferior plans, compared with other individual models. In summary, we believe the improved robustness makes the proposed method more suitable for clinical settings than individual models.

  15. Three-dimensional cluster formation and structure in heterogeneous dose distribution of intensity modulated radiation therapy.

    Science.gov (United States)

    Chao, Ming; Wei, Jie; Narayanasamy, Ganesh; Yuan, Yading; Lo, Yeh-Chi; Peñagarícano, José A

    2018-05-01

    To investigate three-dimensional cluster structure and its correlation to clinical endpoint in heterogeneous dose distributions from intensity modulated radiation therapy. Twenty-five clinical plans from twenty-one head and neck (HN) patients were used for a phenomenological study of the cluster structure formed from the dose distributions of organs at risks (OARs) close to the planning target volumes (PTVs). Initially, OAR clusters were searched to examine the pattern consistence among ten HN patients and five clinically similar plans from another HN patient. Second, clusters of the esophagus from another ten HN patients were scrutinized to correlate their sizes to radiobiological parameters. Finally, an extensive Monte Carlo (MC) procedure was implemented to gain deeper insights into the behavioral properties of the cluster formation. Clinical studies showed that OAR clusters had drastic differences despite similar PTV coverage among different patients, and the radiobiological parameters failed to positively correlate with the cluster sizes. MC study demonstrated the inverse relationship between the cluster size and the cluster connectivity, and the nonlinear changes in cluster size with dose thresholds. In addition, the clusters were insensitive to the shape of OARs. The results demonstrated that the cluster size could serve as an insightful index of normal tissue damage. The clinical outcome of the same dose-volume might be potentially different. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Influence of intensity-modulated radiation therapy on parotid function in nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Cui Tiantian; Wu Shaoxiong; Han Fei; Lu Lixia; Huang Shaomin; Deng Xiaowu; Lu Taixiang; Zhao Chong

    2009-01-01

    Objective: To evaluate the effect of intensity-modulated radiation therapy (IMRT) on parotid function in nasopharyngeal carcinoma (NPC). Methods: Eighty-three NPC patients received prima- ry IMRT between 2001 and 2003. Xerostomia before radiotherapy, at the end of radiotherapy, at 6-month, 1-, 2-,3-,4- and 5-year after radiotherapy were investigated, respectively. The relation between xerostomia and parotid dose distribution was analyzed. Results: Of all the patients, 4, 31, 31 and 17 had stage I, II, III and IV A disease, respectively. Sixteen patients received chemo-radiotherapy. The median followed-up time was 65 months. The 5-year local control and regional control rate were 96% and 95%, respectively. The 5- year overall survival rate was 80%. The mild xerostomia rate at the seven time points was 42%, 51%, 71%, 77%, 58%, 38% and 26%. The corresponding moderate xerostomia rate was 52%, 53%, 21%, 8%, 3%, 2% and 2%, respectively. No serious xerostomia was observed. The mean dose of the bilateral parotid glands was 34.34 Gy. Xerostomia at 6-month after radiotherapy was positively correlated with the mean dose of the parotid glands, and D 50 was the independent factor in predicting the xerostomia. Parotid function was well protected when the mean dose and D 50 were no more than 33 Gy and 29 Gy, respectively. Conclusions: IMRT can improve the local-regional control of NPC and protect the parotid glands from radiation-induced injury. (authors)

  17. Meningioma Causing Visual Impairment: Outcomes and Toxicity After Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Maclean, Jillian, E-mail: jillian.maclean@uclh.nhs.uk [Radiotherapy Department, University College London Hospital, London (United Kingdom); Fersht, Naomi [Radiotherapy Department, University College London Hospital, London (United Kingdom); Bremner, Fion [Neuro-Ophthalmology Department, National Hospital for Neurology and Neurosurgery, London (United Kingdom); Stacey, Chris; Sivabalasingham, Suganya [Radiotherapy Department, University College London Hospital, London (United Kingdom); Short, Susan [Radiotherapy Department, University College London Hospital, London (United Kingdom); Leeds Institute of Molecular Medicine, St James University Hospital, Leeds (United Kingdom)

    2013-03-15

    Purpose: To evaluate ophthalmologic outcomes and toxicity of intensity modulated radiation therapy (IMRT) in patients with meningiomas causing visual deficits. Methods and Materials: A prospective observational study with formal ophthalmologic and clinical assessment of 30 consecutive cases of meningioma affecting vision treated with IMRT from 2007 to 2011. Prescriptions were 50.4 Gy to mean target dose in 28 daily fractions. The median follow-up time was 28 months. Twenty-six meningiomas affected the anterior visual pathway (including 3 optic nerve sheath meningiomas); 4 were posterior to the chiasm. Results: Vision improved objectively in 12 patients (40%). Improvements were in visual field (5/16 patients), color vision (4/9 patients), acuity (1/15 patients), extraocular movements (3/11 patients), ptosis (1/5 patients), and proptosis (2/6 patients). No predictors of clinical response were found. Two patients had minor reductions in tumor dimensions on magnetic resonance imaging, 1 patient had radiological progression, and the other patients were stable. One patient experienced grade 2 keratitis, 1 patient had a minor visual field loss, and 5 patients had grade 1 dry eye. Conclusion: IMRT is an effective method for treating meningiomas causing ophthalmologic deficits, and toxicity is minimal. Thorough ophthalmologic assessment is important because clinical responses often occur in the absence of radiological change.

  18. A novel linear programming approach to fluence map optimization for intensity modulated radiation therapy treatment planning

    International Nuclear Information System (INIS)

    Romeijn, H Edwin; Ahuja, Ravindra K; Dempsey, James F; Kumar, Arvind; Li, Jonathan G

    2003-01-01

    We present a novel linear programming (LP) based approach for efficiently solving the intensity modulated radiation therapy (IMRT) fluence-map optimization (FMO) problem to global optimality. Our model overcomes the apparent limitations of a linear-programming approach by approximating any convex objective function by a piecewise linear convex function. This approach allows us to retain the flexibility offered by general convex objective functions, while allowing us to formulate the FMO problem as a LP problem. In addition, a novel type of partial-volume constraint that bounds the tail averages of the differential dose-volume histograms of structures is imposed while retaining linearity as an alternative approach to improve dose homogeneity in the target volumes, and to attempt to spare as many critical structures as possible. The goal of this work is to develop a very rapid global optimization approach that finds high quality dose distributions. Implementation of this model has demonstrated excellent results. We found globally optimal solutions for eight 7-beam head-and-neck cases in less than 3 min of computational time on a single processor personal computer without the use of partial-volume constraints. Adding such constraints increased the running times by a factor of 2-3, but improved the sparing of critical structures. All cases demonstrated excellent target coverage (>95%), target homogeneity (<10% overdosing and <7% underdosing) and organ sparing using at least one of the two models

  19. Comparison of two heterogeneity correction algorithms in pituitary gland treatments with intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Albino, Lucas D.; Santos, Gabriela R.; Ribeiro, Victor A.B.; Rodrigues, Laura N.; Weltman, Eduardo; Braga, Henrique F.

    2013-01-01

    The dose accuracy calculated by a treatment planning system is directly related to the chosen algorithm. Nowadays, several calculation doses algorithms are commercially available and they differ in calculation time and accuracy, especially when individual tissue densities are taken into account. The aim of this study was to compare two different calculation algorithms from iPlan®, BrainLAB, in the treatment of pituitary gland tumor with intensity-modulated radiation therapy (IMRT). These tumors are located in a region with variable electronic density tissues. The deviations from the plan with no heterogeneity correction were evaluated. To initial validation of the data inserted into the planning system, an IMRT plan was simulated in a anthropomorphic phantom and the dose distribution was measured with a radiochromic film. The gamma analysis was performed in the film, comparing it with dose distributions calculated with X-ray Voxel Monte Carlo (XVMC) algorithm and pencil beam convolution (PBC). Next, 33 patients plans, initially calculated by PBC algorithm, were recalculated with XVMC algorithm. The treatment volumes and organs-at-risk dose-volume histograms were compared. No relevant differences were found in dose-volume histograms between XVMC and PBC. However, differences were obtained when comparing each plan with the plan without heterogeneity correction. (author)

  20. Intensity-modulated radiation therapy for nasopharyngeal carcinoma parotid sparing with euivalent uiform dose optimization

    International Nuclear Information System (INIS)

    Yue Weiyou; Dai Jianrong; Gao Li

    2006-01-01

    Objective: The aim of this study was to evaluate the role of an euivalent uiform dose (EUD) based optimization algorithm in sparing the parotids of patients with nasopharyngeal carcinoma (NPC) when they are treated with intensity-modulated radiation therapy (IMRT). Methods: 12 patients were randomly selected from the NPC patients who received IMRT treatments. For these patients, the treatment plans were designed with physical optimization constraints (dose/dose-volume constraints). Based on these plans, new plans were designed through replacing the physical constraints with maximum EUD for parotids, while keeping the physical objectives for targets and other organs at risk(OARs) unchanged. Comparison was then made between the new plan, which had EUD constraints to parotids, and the former for each individual patient. Results: While maintaining the dose to the targets and the other OARs un- changed, optimization with EUD constraints to parotids decreased the mean dose and V 30 of parotids significantly, simultaneously, the dose of target volume and other organs at risk keep stable, the values of probability were less than 0.05 by T-test. Conclusions: The doses to parotids can be reduced through optimization with EUD constraints. This finding is quite helpful to reduce the occurrence rate of parotid complications, and to provide spaces for escalating target dose. (authors)

  1. In vivo measurements with MOSFET detectors in oropharynx and nasopharynx intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Marcie, Serge; Charpiot, Elisabeth; Bensadoun, Rene-Jean; Ciais, Gaston; Herault, Joel; Costa, Andre; Gerard, Jean-Pierre

    2005-01-01

    Purpose: To evaluate the feasibility of in vivo measurements with metal oxide semiconductor field effect transistor (MOSFET) dosimeters for oropharynx and nasopharynx intensity-modulated radiation therapy (IMRT). Methods and Materials: During a 1-year period, in vivo measurements of the dose delivered to one or two points of the oral cavity by IMRT were obtained with MOSFET dosimeters. Measurements were obtained during each session of 48 treatment plans for 21 patients, all of whom were fitted with a custom-made mouth plate. Calculated and measured values were compared. Results: A total of 344 and 452 measurements were performed for the right and left sides, respectively, of the oral cavity. Seventy percent of the discrepancies between calculated and measured values were within ±5%. Uncertainties were due to interfraction patient positions, intrafraction patient movements, and interfraction MOSFET positions. Nevertheless, the discrepancies between the measured and calculated means were within ±5% for 92% and 95% of the right and left sides, respectively. Comparison of these discrepancies and the discrepancies between calculated values and measurements made on a phantom revealed that all differences were within ±5%. Conclusion: Our experience demonstrates the feasibility of in vivo measurements with MOSFET dosimeters for oropharynx and nasopharynx IMRT

  2. Rational use of intensity-modulated radiation therapy: the importance of clinical outcome.

    Science.gov (United States)

    De Neve, Wilfried; De Gersem, Werner; Madani, Indira

    2012-01-01

    During the last 2 decades, intensity-modulated radiation therapy (IMRT) became a standard technique despite its drawbacks of volume delineation, planning, robustness of delivery, challenging quality assurance, and cost as compared with non-IMRT. The theoretic advantages of IMRT dose distributions are generally accepted, but the clinical advantages remain debatable because of the lack of clinical assessment of the effort that is required to overshadow the disadvantages. Rational IMRT use requires a positive advantage/drawback balance. Only 5 randomized clinical trials (RCTs), 3 in the breast and 2 in the head and neck, which compare IMRT with non-IMRT (2-dimensional technique in four fifths of the trials), have been published (as of March 2011), and all had toxicity as the primary endpoint. More than 50 clinical trials compared results of IMRT-treated patients with a non-IMRT group, mostly historical controls. RCTs systematically showed a lower toxicity in IMRT-treated patients, and the non-RCTs confirmed these findings. Toxicity reduction, counterbalancing the drawbacks of IMRT, was convincing for breast and head and neck IMRT. For other tumor sites, the arguments favoring IMRT are weaker because of the inability to control bias outside the randomized setting. For anticancer efficacy endpoints, like survival, disease-specific survival, or locoregional control, the balance between advantages and drawbacks is fraught with uncertainties because of the absence of robust clinical data. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. A modified method of planning and delivery for dynamic multileaf collimator intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Dogan, Nesrin; Leybovich, Leonid B.; Sethi, Anil; Krasin, Matthew; Emami, Bahman

    2000-01-01

    Purpose: To develop a modified planning and delivery technique that reduces dose nonuniformity for tomographic delivery of intensity-modulated radiation therapy (IMRT). Methods and Materials: The NOMOS-CORVUS system delivers IMRT in a tomographic paradigm. This type of delivery is prone to create multiple dose nonuniformity regions at the arc abutment regions. The modified technique was based on the cyclical behavior of arc positions as a function of a target length. With the modified technique, two plans are developed for the same patient, one with the original target and the second with a slightly increased target length and the abutment regions shifted by ∼5 mm compared to the first plan. Each plan is designed to deliver half of the target prescription dose delivered on alternate days, resulting in periodic shifts of abutment regions. This method was experimentally tested in phantoms with and without intentionally introduced errors in couch indexing. Results: With the modified technique, the degree of dose nonuniformity was reduced. For example, with 1 mm error in couch indexing, the degree of dose nonuniformity changed from ∼25% to ∼12%. Conclusion: Use of the modified technique reduces dose nonuniformity due to periodic shifts of abutment regions during treatment delivery

  4. A fast optimization algorithm for multicriteria intensity modulated proton therapy planning

    International Nuclear Information System (INIS)

    Chen Wei; Craft, David; Madden, Thomas M.; Zhang, Kewu; Kooy, Hanne M.; Herman, Gabor T.

    2010-01-01

    Purpose: To describe a fast projection algorithm for optimizing intensity modulated proton therapy (IMPT) plans and to describe and demonstrate the use of this algorithm in multicriteria IMPT planning. Methods: The authors develop a projection-based solver for a class of convex optimization problems and apply it to IMPT treatment planning. The speed of the solver permits its use in multicriteria optimization, where several optimizations are performed which span the space of possible treatment plans. The authors describe a plan database generation procedure which is customized to the requirements of the solver. The optimality precision of the solver can be specified by the user. Results: The authors apply the algorithm to three clinical cases: A pancreas case, an esophagus case, and a tumor along the rib cage case. Detailed analysis of the pancreas case shows that the algorithm is orders of magnitude faster than industry-standard general purpose algorithms (MOSEK's interior point optimizer, primal simplex optimizer, and dual simplex optimizer). Additionally, the projection solver has almost no memory overhead. Conclusions: The speed and guaranteed accuracy of the algorithm make it suitable for use in multicriteria treatment planning, which requires the computation of several diverse treatment plans. Additionally, given the low memory overhead of the algorithm, the method can be extended to include multiple geometric instances and proton range possibilities, for robust optimization.

  5. Comparison of optimization algorithms in intensity-modulated radiation therapy planning

    Science.gov (United States)

    Kendrick, Rachel

    Intensity-modulated radiation therapy is used to better conform the radiation dose to the target, which includes avoiding healthy tissue. Planning programs employ optimization methods to search for the best fluence of each photon beam, and therefore to create the best treatment plan. The Computational Environment for Radiotherapy Research (CERR), a program written in MATLAB, was used to examine some commonly-used algorithms for one 5-beam plan. Algorithms include the genetic algorithm, quadratic programming, pattern search, constrained nonlinear optimization, simulated annealing, the optimization method used in Varian EclipseTM, and some hybrids of these. Quadratic programing, simulated annealing, and a quadratic/simulated annealing hybrid were also separately compared using different prescription doses. The results of each dose-volume histogram as well as the visual dose color wash were used to compare the plans. CERR's built-in quadratic programming provided the best overall plan, but avoidance of the organ-at-risk was rivaled by other programs. Hybrids of quadratic programming with some of these algorithms seems to suggest the possibility of better planning programs, as shown by the improved quadratic/simulated annealing plan when compared to the simulated annealing algorithm alone. Further experimentation will be done to improve cost functions and computational time.

  6. Automation of the solution type of intensity modulated radiation therapy with direct planning neoplastic breast lesions

    International Nuclear Information System (INIS)

    Fuente Rosales, Liset De La; Larrinaga Cortina, Eduardo Francisco

    2009-01-01

    Breast cancer ranks first among the lesions malignancies involving the Cuban women and the second in mortality only surpassed by lung injury. The breast-conserving surgery is becoming less appeal, with an increase in the choice of radiotherapy to the breast operated, and the surgical bed. Intensity Modulated Radiation Therapy, IMRT has demonstrated better results in the dose distribution for irradiation dimensional treatment breast shaping, 3DCRT. We developed a MATLAB application to obtain the solution type to direct planning IMRT for breast neoplasm. The technique was implemented in the Planning System Treatment Plus Theraplan v3.8 and Precise1 ELEKTA linear accelerator. Static segments are constructed for each portal of incidence and Excel files are exported as the positions of the blades. The technique was validated with a patient, which he performed a radiographic study of computerized axial tomography planning purposes. The standard solution built is consistent with those reported internationally and consists of a segment type and at least two segments of type B. The assignment of the relative weights of the segments is done manually by trial and error procedure, with the general rule of 90% by weight assigned to segment A and the remaining 10% divided equally between B-type segments IMRT breast obtained in a dose 17% homogeneity better than 3DCRT and reduced the average dose in the lung ipsilateral 15%. (author)

  7. A fast optimization algorithm for multicriteria intensity modulated proton therapy planning.

    Science.gov (United States)

    Chen, Wei; Craft, David; Madden, Thomas M; Zhang, Kewu; Kooy, Hanne M; Herman, Gabor T

    2010-09-01

    To describe a fast projection algorithm for optimizing intensity modulated proton therapy (IMPT) plans and to describe and demonstrate the use of this algorithm in multicriteria IMPT planning. The authors develop a projection-based solver for a class of convex optimization problems and apply it to IMPT treatment planning. The speed of the solver permits its use in multicriteria optimization, where several optimizations are performed which span the space of possible treatment plans. The authors describe a plan database generation procedure which is customized to the requirements of the solver. The optimality precision of the solver can be specified by the user. The authors apply the algorithm to three clinical cases: A pancreas case, an esophagus case, and a tumor along the rib cage case. Detailed analysis of the pancreas case shows that the algorithm is orders of magnitude faster than industry-standard general purpose algorithms (MOSEK'S interior point optimizer, primal simplex optimizer, and dual simplex optimizer). Additionally, the projection solver has almost no memory overhead. The speed and guaranteed accuracy of the algorithm make it suitable for use in multicriteria treatment planning, which requires the computation of several diverse treatment plans. Additionally, given the low memory overhead of the algorithm, the method can be extended to include multiple geometric instances and proton range possibilities, for robust optimization.

  8. 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

  9. Beam angle optimization for intensity-modulated radiation therapy using a guided pattern search method

    International Nuclear Information System (INIS)

    Rocha, Humberto; Dias, Joana M; Ferreira, Brígida C; Lopes, Maria C

    2013-01-01

    Generally, the inverse planning of radiation therapy consists mainly of the fluence optimization. The beam angle optimization (BAO) in intensity-modulated radiation therapy (IMRT) consists of selecting appropriate radiation incidence directions and may influence the quality of the IMRT plans, both to enhance better organ sparing and to improve tumor coverage. However, in clinical practice, most of the time, beam directions continue to be manually selected by the treatment planner without objective and rigorous criteria. The goal of this paper is to introduce a novel approach that uses beam’s-eye-view dose ray tracing metrics within a pattern search method framework in the optimization of the highly non-convex BAO problem. Pattern search methods are derivative-free optimization methods that require a few function evaluations to progress and converge and have the ability to better avoid local entrapment. The pattern search method framework is composed of a search step and a poll step at each iteration. The poll step performs a local search in a mesh neighborhood and ensures the convergence to a local minimizer or stationary point. The search step provides the flexibility for a global search since it allows searches away from the neighborhood of the current iterate. Beam’s-eye-view dose metrics assign a score to each radiation beam direction and can be used within the pattern search framework furnishing a priori knowledge of the problem so that directions with larger dosimetric scores are tested first. A set of clinical cases of head-and-neck tumors treated at the Portuguese Institute of Oncology of Coimbra is used to discuss the potential of this approach in the optimization of the BAO problem. (paper)

  10. Replanning During Intensity Modulated Radiation Therapy Improved Quality of Life in Patients With Nasopharyngeal Carcinoma

    International Nuclear Information System (INIS)

    Yang Haihua; Hu Wei; Wang Wei; Chen Peifang; Ding Weijun; Luo Wei

    2013-01-01

    Purpose: Anatomic and dosimetric changes have been reported during intensity modulated radiation therapy (IMRT) in patients with nasopharyngeal carcinoma (NPC). The purpose of this study was to evaluate the effects of replanning on quality of life (QoL) and clinical outcomes during the course of IMRT for NPC patients. Methods and Materials: Between June 2007 and August 2011, 129 patients with NPC were enrolled. Forty-three patients received IMRT without replanning, while 86 patients received IMRT replanning after computed tomography (CT) images were retaken part way through therapy. Chinese versions of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 and Head and Neck Quality of Life Questionnaire 35 were completed before treatment began and at the end of treatment and at 1, 3, 6, and 12 months after the completion of treatment. Overall survival (OS) data were compared using the Kaplan-Meier method. Results: IMRT replanning had a profound impact on the QoL of NPC patients, as determined by statistically significant changes in global QoL and other QoL scales. Additionally, the clinical outcome comparison indicates that replanning during IMRT for NPC significantly improved 2-year local regional control (97.2% vs 92.4%, respectively, P=.040) but did not improve 2-year OS (89.8% vs 82.2%, respectively, P=.475). Conclusions: IMRT replanning improves QoL as well as local regional control in patients with NPC. Future research is needed to determine the criteria for replanning for NPC patients undergoing IMRT.

  11. Kilovoltage Intrafraction Monitoring for Prostate Intensity Modulated Arc Therapy: First Clinical Results

    International Nuclear Information System (INIS)

    Ng, Jin Aun; Booth, Jeremy T.; Poulsen, Per R.; Fledelius, Walther; Worm, Esben Schjødt; Eade, Thomas; Hegi, Fiona; Kneebone, Andrew; Kuncic, Zdenka; Keall, Paul J.

    2012-01-01

    Purpose: Most linear accelerators purchased today are equipped with a gantry-mounted kilovoltage X-ray imager which is typically used for patient imaging prior to therapy. A novel application of the X-ray system is kilovoltage intrafraction monitoring (KIM), in which the 3-dimensional (3D) tumor position is determined during treatment. In this paper, we report on the first use of KIM in a prospective clinical study of prostate cancer patients undergoing intensity modulated arc therapy (IMAT). Methods and Materials: Ten prostate cancer patients with implanted fiducial markers undergoing conventionally fractionated IMAT (RapidArc) were enrolled in an ethics-approved study of KIM. KIM involves acquiring kV images as the gantry rotates around the patient during treatment. Post-treatment, markers in these images were segmented to obtain 2D positions. From the 2D positions, a maximum likelihood estimation of a probability density function was used to obtain 3D prostate trajectories. The trajectories were analyzed to determine the motion type and the percentage of time the prostate was displaced ≥3, 5, 7, and 10 mm. Independent verification of KIM positional accuracy was performed using kV/MV triangulation. Results: KIM was performed for 268 fractions. Various prostate trajectories were observed (ie, continuous target drift, transient excursion, stable target position, persistent excursion, high-frequency excursions, and erratic behavior). For all patients, 3D displacements of ≥3, 5, 7, and 10 mm were observed 5.6%, 2.2%, 0.7% and 0.4% of the time, respectively. The average systematic accuracy of KIM was measured at 0.46 mm. Conclusions: KIM for prostate IMAT was successfully implemented clinically for the first time. Key advantages of this method are (1) submillimeter accuracy, (2) widespread applicability, and (3) a low barrier to clinical implementation. A disadvantage is that KIM delivers additional imaging dose to the patient.

  12. Postmastectomy intensity modulated radiation therapy following immediate expander-implant reconstruction

    International Nuclear Information System (INIS)

    Koutcher, Lawrence; Ballangrud, Ase; Cordeiro, Peter G.; McCormick, Beryl; Hunt, Margie; Zee, Kimberly J. Van; Hudis, Clifford; Beal, Kathryn

    2010-01-01

    Background/purpose: To evaluate radiation plans of patients undergoing mastectomy with immediate expander-implant reconstruction followed by postmastectomy radiation therapy (PMRT). Materials/methods: We identified 41 patients from June 2004 to May 2007 who underwent mastectomy, immediate expander-implant reconstruction, and PMRT with intensity-modulated radiation therapy. We assessed chest wall (CW) coverage and volume of heart and lung irradiated. Results: In 73% of patients, all CW borders were adequately covered, and in 22%, all but 1 border were adequately covered. The total lung V 20 was 20 was 13% (range, 3-23%), and the mean heart D mean was 2.81 Gy (range, 0.53-9.60 Gy). In patients with left-sided lesions without internal mammary nodes (IMNs) treatment (n = 22), the mean lung V 20 was 12.6% and the mean heart D mean was 3.90 Gy, and in the patient with IMN treatment, the lung V 20 was 18% and heart D mean was 8.04 Gy. For right-sided lesions without IMN treatment (n = 12), the mean lung V 20 was 12.4% and the mean heart D mean was 0.90 Gy, and in patients with IMN treatment (n = 6), these numbers were 17.8% and 1.76 Gy. At a median follow-up of 29 months, the 30-month actuarial local control was 97%. Conclusions: In women undergoing immediate expander-implant reconstruction, PMRT can achieve excellent local control with acceptable heart and lung doses. These results can be achieved even when the IMN are being treated, although doses to the heart and lungs will be higher.

  13. Adoption of Intensity Modulated Radiation Therapy For Early-Stage Breast Cancer From 2004 Through 2011

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Elyn H. [Yale School of Medicine, New Haven, Connecticut (United States); Mougalian, Sarah S. [Yale School of Medicine, New Haven, Connecticut (United States); Yale Cancer Center, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Soulos, Pamela R. [Yale School of Medicine, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut (United States); Smith, Benjamin D. [Department of Radiation Oncology, MD Anderson Cancer Center, Houston, Texas (United States); Haffty, Bruce G. [Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey (United States); Gross, Cary P. [Yale School of Medicine, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut (United States); Yu, James B., E-mail: james.b.yu@yale.edu [Yale School of Medicine, New Haven, Connecticut (United States); Cancer Outcomes, Public Policy, and Effectiveness Research Center at Yale, New Haven, Connecticut (United States); Department of Therapeutic Radiology, Yale School of Medicine, New Haven, Connecticut (United States)

    2015-02-01

    Purpose: Intensity modulated radiation therapy (IMRT) is a newer method of radiation therapy (RT) that has been increasingly adopted as an adjuvant treatment after breast-conserving surgery (BCS). IMRT may result in improved cosmesis compared to standard RT, although at greater expense. To investigate the adoption of IMRT, we examined trends and factors associated with IMRT in women under the age of 65 with early stage breast cancer. Methods and Materials: We performed a retrospective study of early stage breast cancer patients treated with BCS followed by whole-breast irradiation (WBI) who were ≤65 years old in the National Cancer Data Base from 2004 to 2011. We used logistic regression to identify factors associated with receipt of IMRT (vs standard RT). Results: We identified 11,089 women with early breast cancer (9.6%) who were treated with IMRT and 104,448 (90.4%) who were treated with standard RT, after BCS. The proportion of WBI patients receiving IMRT increased yearly from 2004 to 2009, with 5.3% of WBI patients receiving IMRT in 2004 and 11.6% receiving IMRT in 2009. Further use of IMRT declined afterward, with the proportion remaining steady at 11.0% and 10.7% in 2010 and 2011, respectively. Patients treated in nonacademic community centers were more likely to receive IMRT (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.30-1.43 for nonacademic vs academic center). Compared to privately insured patients, the uninsured patients (OR, 0.81; 95% CI, 0.70-0.95) and those with Medicaid insurance (OR, 0.87; 95% CI, 0.79-0.95) were less likely to receive IMRT. Conclusions: The use of IMRT rose from 2004 to 2009 and then stabilized. Important nonclinical factors associated with IMRT use included facility type and insurance status.

  14. Adoption of Intensity Modulated Radiation Therapy For Early-Stage Breast Cancer From 2004 Through 2011

    International Nuclear Information System (INIS)

    Wang, Elyn H.; Mougalian, Sarah S.; Soulos, Pamela R.; Smith, Benjamin D.; Haffty, Bruce G.; Gross, Cary P.; Yu, James B.

    2015-01-01

    Purpose: Intensity modulated radiation therapy (IMRT) is a newer method of radiation therapy (RT) that has been increasingly adopted as an adjuvant treatment after breast-conserving surgery (BCS). IMRT may result in improved cosmesis compared to standard RT, although at greater expense. To investigate the adoption of IMRT, we examined trends and factors associated with IMRT in women under the age of 65 with early stage breast cancer. Methods and Materials: We performed a retrospective study of early stage breast cancer patients treated with BCS followed by whole-breast irradiation (WBI) who were ≤65 years old in the National Cancer Data Base from 2004 to 2011. We used logistic regression to identify factors associated with receipt of IMRT (vs standard RT). Results: We identified 11,089 women with early breast cancer (9.6%) who were treated with IMRT and 104,448 (90.4%) who were treated with standard RT, after BCS. The proportion of WBI patients receiving IMRT increased yearly from 2004 to 2009, with 5.3% of WBI patients receiving IMRT in 2004 and 11.6% receiving IMRT in 2009. Further use of IMRT declined afterward, with the proportion remaining steady at 11.0% and 10.7% in 2010 and 2011, respectively. Patients treated in nonacademic community centers were more likely to receive IMRT (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.30-1.43 for nonacademic vs academic center). Compared to privately insured patients, the uninsured patients (OR, 0.81; 95% CI, 0.70-0.95) and those with Medicaid insurance (OR, 0.87; 95% CI, 0.79-0.95) were less likely to receive IMRT. Conclusions: The use of IMRT rose from 2004 to 2009 and then stabilized. Important nonclinical factors associated with IMRT use included facility type and insurance status

  15. Fast voxel and polygon ray-tracing algorithms in intensity modulated radiation therapy treatment planning

    International Nuclear Information System (INIS)

    Fox, Christopher; Romeijn, H. Edwin; Dempsey, James F.

    2006-01-01

    We present work on combining three algorithms to improve ray-tracing efficiency in radiation therapy dose computation. The three algorithms include: An improved point-in-polygon algorithm, incremental voxel ray tracing algorithm, and stereographic projection of beamlets for voxel truncation. The point-in-polygon and incremental voxel ray-tracing algorithms have been used in computer graphics and nuclear medicine applications while the stereographic projection algorithm was developed by our group. These algorithms demonstrate significant improvements over the current standard algorithms in peer reviewed literature, i.e., the polygon and voxel ray-tracing algorithms of Siddon for voxel classification (point-in-polygon testing) and dose computation, respectively, and radius testing for voxel truncation. The presented polygon ray-tracing technique was tested on 10 intensity modulated radiation therapy (IMRT) treatment planning cases that required the classification of between 0.58 and 2.0 million voxels on a 2.5 mm isotropic dose grid into 1-4 targets and 5-14 structures represented as extruded polygons (a.k.a. Siddon prisms). Incremental voxel ray tracing and voxel truncation employing virtual stereographic projection was tested on the same IMRT treatment planning cases where voxel dose was required for 230-2400 beamlets using a finite-size pencil-beam algorithm. Between a 100 and 360 fold cpu time improvement over Siddon's method was observed for the polygon ray-tracing algorithm to perform classification of voxels for target and structure membership. Between a 2.6 and 3.1 fold reduction in cpu time over current algorithms was found for the implementation of incremental ray tracing. Additionally, voxel truncation via stereographic projection was observed to be 11-25 times faster than the radial-testing beamlet extent approach and was further improved 1.7-2.0 fold through point-classification using the method of translation over the cross product technique

  16. SU-E-T-124: Dosimetric Comparison of HDR Brachytherapy and Intensity Modulated Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J [Purdue University, West Lafayette, IN (United States); Wu, H [IUPUI, Indianapolis, IN (United States); Das, I [Indiana University- School of Medicine, Indianapolis, IN (United States)

    2014-06-01

    Purpose: Brachytherapy is known to be able to deliver more radiation dose to tumor while minimizing radiation dose to surrounding normal tissues. Proton therapy also provides superior dose distribution due to Bragg peak. Since both HDR and Intensity Modulated Proton Therapy (IMPT) are beneficial for their quick dose drop off, our goal in this study is to compare the pace of dose gradient drop-off between HDR and IMPT plans based on the same CT image data-set. In addition, normal tissues sparing were also compared among HDR, IMPT and SBRT. Methods: Five cervical cancer cases treated with EBRT + HDR boost combination with Tandem and Ovoid applicator were used for comparison purpose. Original HDR plans with prescribed dose of 5.5 Gy x 5 fractions were generated and optimized. The 100% isodose line of HDR plans was converted to a dose volume, and treated as CTV for IMPT and SBRT planning. The same HDR CT scans were also used for IMPT plan and SBRT plan for direct comparison. The philosophy of the IMPT and SBRT planning was to create the same CTV coverage as HDR plans. All three modalities treatment plans were compared to each other with a set of predetermined criteria. Results: With similar target volume coverage in cervix cancer boost treatment, HDR provides a slightly sharper dose drop-off from 100% to 50% isodose line, averagely in all directions compared to IMPT. However, IMPT demonstrated more dose gradient drop-off at the junction of the target and normal tissues by providing more normal tissue sparing and superior capability to reduce integral dose. Conclusion: IMPT is capable of providing comparable dose drop-off as HDR. IMPT can be explored as replacement for HDR brachytherapy in various applications.

  17. Intensity-Modulated Radiation Therapy in the Salvage of Locally Recurrent Nasopharyngeal Carcinoma

    International Nuclear Information System (INIS)

    Qiu Sufang; Lin Shaojun; Tham, Ivan W.K.; Pan Jianji; Lu Jun; Lu, Jiade J.

    2012-01-01

    Purpose: Local recurrences of nasopharyngeal carcinoma (NPC) may be salvaged by reirradiation with conventional techniques, but with significant morbidity. Intensity-modulated radiation therapy (IMRT) may improve the therapeutic ratio by reducing doses to normal tissue. The aim of this study was to address the efficacy and toxicity profile of IMRT for a cohort of patients with locally recurrent NPC. Methods and Materials: Between August 2003 and June 2009, 70 patients with radiologic or pathologically proven locally recurrent NPC were treated with IMRT. The median time to recurrence was 30 months after the completion of conventional radiation to definitive dose. Fifty-seven percent of the tumors were classified asrT3–4. The minimum planned doses were 59.4 to 60 Gy in 1.8- to 2-Gy fractions per day to the gross disease with margins, with or without chemotherapy. Results: The median dose to the recurrent tumor was 70 Gy (range, 50–77.4 Gy). Sixty-five patients received the planned radiation therapy; 5 patients received between 50 and 60 Gy because of acute side effects. With a median follow-up time of 25 months, the rates of 2-year locoregional recurrence-free survival, disease-free survival, and overall survival were 65.8%, 65.8%, and 67.4%, respectively. Moderate to severe late toxicities were noted in 25 patients (35.7%). Eleven patients (15.7%) had posterior nasal space ulceration, 17 (24.3%) experienced cranial nerve palsies, 12 (17.1%) had trismus, and 12 (17.1%) experienced deafness. Extended disease-free interval (relative risk 2.049) and advanced T classification (relative risk 3.895) at presentation were adverse prognostic factors. Conclusion: Reirradiation with IMRT provides reasonable long-term control in patients with locally recurrent NPC.

  18. Expert Consensus Contouring Guidelines for Intensity Modulated Radiation Therapy in Esophageal and Gastroesophageal Junction Cancer

    International Nuclear Information System (INIS)

    Wu, Abraham J.; Bosch, Walter R.; Chang, Daniel T.; Hong, Theodore S.; Jabbour, Salma K.; Kleinberg, Lawrence R.; Mamon, Harvey J.; Thomas, Charles R.; Goodman, Karyn A.

    2015-01-01

    Purpose/Objective(s): Current guidelines for esophageal cancer contouring are derived from traditional 2-dimensional fields based on bony landmarks, and they do not provide sufficient anatomic detail to ensure consistent contouring for more conformal radiation therapy techniques such as intensity modulated radiation therapy (IMRT). Therefore, we convened an expert panel with the specific aim to derive contouring guidelines and generate an atlas for the clinical target volume (CTV) in esophageal or gastroesophageal junction (GEJ) cancer. Methods and Materials: Eight expert academically based gastrointestinal radiation oncologists participated. Three sample cases were chosen: a GEJ cancer, a distal esophageal cancer, and a mid-upper esophageal cancer. Uniform computed tomographic (CT) simulation datasets and accompanying diagnostic positron emission tomographic/CT images were distributed to each expert, and the expert was instructed to generate gross tumor volume (GTV) and CTV contours for each case. All contours were aggregated and subjected to quantitative analysis to assess the degree of concordance between experts and to generate draft consensus contours. The panel then refined these contours to generate the contouring atlas. Results: The κ statistics indicated substantial agreement between panelists for each of the 3 test cases. A consensus CTV atlas was generated for the 3 test cases, each representing common anatomic presentations of esophageal cancer. The panel agreed on guidelines and principles to facilitate the generalizability of the atlas to individual cases. Conclusions: This expert panel successfully reached agreement on contouring guidelines for esophageal and GEJ IMRT and generated a reference CTV atlas. This atlas will serve as a reference for IMRT contours for clinical practice and prospective trial design. Subsequent patterns of failure analyses of clinical datasets using these guidelines may require modification in the future

  19. Disease Control After Reduced Volume Conformal and Intensity Modulated Radiation Therapy for Childhood Craniopharyngioma

    Energy Technology Data Exchange (ETDEWEB)

    Merchant, Thomas E., E-mail: thomas.merchant@stjude.org [St Jude Children' s Research Hospital, Radiological Sciences, Memphis, Tennessee (United States); Kun, Larry E.; Hua, Chia-Ho [St Jude Children' s Research Hospital, Radiological Sciences, Memphis, Tennessee (United States); Wu, Shengjie; Xiong, Xiaoping [St Jude Children' s Research Hospital, Biostatistics, Memphis, Tennessee (United States); Sanford, Robert A.; Boop, Frederick A. [Semmes Murphey Neurologic and Spine Institute, Neurosurgery, Memphis, Tennessee (United States)

    2013-03-15

    Purpose: To estimate the rate of disease control after conformal radiation therapy using reduced clinical target volume (CTV) margins and to determine factors that predict for tumor progression. Methods and Materials: Eighty-eight children (median age, 8.5 years; range, 3.2-17.6 years) received conformal or intensity modulated radiation therapy between 1998 and 2009. The study group included those prospectively treated from 1998 to 2003, using a 10-mm CTV, defined as the margin surrounding the solid and cystic tumor targeted to receive the prescription dose of 54 Gy. The CTV margin was subsequently reduced after 2003, yielding 2 groups of patients: those treated with a CTV margin greater than 5 mm (n=26) and those treated with a CTV margin less than or equal to 5 mm (n=62). Disease progression was estimated on the basis of additional variables including sex, race, extent of resection, tumor interventions, target volume margins, and frequency of weekly surveillance magnetic resonance (MR) imaging during radiation therapy. Median follow-up was 5 years. Results: There was no difference between progression-free survival rates based on CTV margins (>5 mm vs ≤5 mm) at 5 years (88.1% ± 6.3% vs 96.2% ± 4.4% [P=.6386]). There were no differences based on planning target volume (PTV) margins (or combined CTV plus PTV margins). The PTV was systematically reduced from 5 to 3 mm during the time period of the study. Factors predictive of superior progression-free survival included Caucasian race (P=.0175), no requirement for cerebrospinal fluid shunting (P=.0066), and number of surveillance imaging studies during treatment (P=.0216). Patients whose treatment protocol included a higher number of weekly surveillance MR imaging evaluations had a lower rate of tumor progression. Conclusions: These results suggest that targeted volume reductions for radiation therapy using smaller margins are feasible and safe but require careful monitoring. We are currently investigating

  20. Image Guided Hypofractionated Postprostatectomy Intensity Modulated Radiation Therapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Stephen L.; Patel, Pretesh; Song, Haijun [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Freedland, Stephen J. [Surgery Section, Durham Veterans Administration, and Division of Urology, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California (United States); Bynum, Sigrun; Oh, Daniel; Palta, Manisha; Yoo, David; Oleson, James [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Salama, Joseph K., E-mail: joseph.salama@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States)

    2016-03-01

    Purpose: Hypofractionated radiation therapy (RT) has promising long-term biochemical relapse-free survival (bRFS) with comparable toxicity for definitive treatment of prostate cancer. However, data reporting outcomes after adjuvant and salvage postprostatectomy hypofractionated RT are sparse. Therefore, we report the toxicity and clinical outcomes after postprostatectomy hypofractionated RT. Methods and Materials: From a prospectively maintained database, men receiving image guided hypofractionated intensity modulated RT (HIMRT) with 2.5-Gy fractions constituted our study population. Androgen deprivation therapy was used at the discretion of the radiation oncologist. Acute toxicities were graded according to the Common Terminology Criteria for Adverse Events version 4.0. Late toxicities were scored using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer scale. Biochemical recurrence was defined as an increase of 0.1 in prostate-specific antigen (PSA) from posttreatment nadir or an increase in PSA despite treatment. The Kaplan-Meier method was used for the time-to-event outcomes. Results: Between April 2008 and April 2012, 56 men received postoperative HIMRT. The median follow-up time was 48 months (range, 21-67 months). Thirty percent had pre-RT PSA <0.1; the median pre-RT detectable PSA was 0.32 ng/mL. The median RT dose was 65 Gy (range, 57.5-65 Gy). Ten patients received neoadjuvant and concurrent hormone therapy. Posttreatment acute urinary toxicity was limited. There was no acute grade 3 toxicity. Late genitourinary (GU) toxicity of any grade was noted in 52% of patients, 40% of whom had pre-RT urinary incontinence. The 4-year actuarial rate of late grade 3 GU toxicity (exclusively gross hematuria) was 28% (95% confidence interval [CI], 16%-41%). Most grade 3 GU toxicity resolved; only 7% had persistent grade ≥3 toxicity at the last follow-up visit. Fourteen patients experienced biochemical recurrence at a

  1. SU-E-T-449: Hippocampal Sparing Radiotherapy Using Intensity Modulated Radiotherapy and Volumetric Modulated Arc Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Moon, S [Korea University, Seoul (Korea, Republic of); Kyung Hee University Hospital at Gangdong, Gangdong-gu (Korea, Republic of); Kim, D; Chung, W [Kyung Hee University Hospital at Gangdong, Gangdong-gu (Korea, Republic of); Yoon, M [Korea University, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: The hippocampus sparing during the cranial irradiation has become interesting because it may mitigate radiation-induced neurocognitive toxicity. Herein we report our preliminary study for sparing the hippocampus with and without tilling condition for patient with brain metastases. Methods: Ten patients previously treated with whole brain were reviewed. Five patients tilted the head to around 30 degrees and others were treated without tilting. Treatment plans of linear accelerator (Linac)-based volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) were generated for prescription dose of 30 Gy in 15 fractions. Hippocampal avoidance regions were created with 5-mm volumetric expansion around the hippocampus. Whole brain, hippocampus and hippocampal avoidance volume were 1372cm3, 6cm3 and 30cm3 and hippocampal avoidance volume was 2.2% of the whole brain planned target volume in average. Organs at risk (OARs) are hippocampus, eyes, lens, and cochleae. Coverage index (CVI), conformity index (CI), homogeneity index (HI) and mean dose to OARs were used to compare dose characteristic of tilted and non-tilted cases. Results: In IMRT, when CI, CVI and HI of whole brain were 0.88, 0.09 and 0.98 in both tilted and non-tilted cases, absorbed dose of hippocampal avoidance volume in tilted cases were 10% lower than non-tilted cases. Doses in other OARs such as eyes, lens, and cochleae were also decreased about 20% when tilting the head. When CI, HI and CVI in VMAT were 0.9, 0.08 and 0.99, the dose-decreased ratio of OARs in both with and without tilting cases were almost the same with IMRT. But absolute dose of hippocampal avoidance volume in VMAT was 30% lower than IMRT. Conclusion: This study confirms that dose to hippocampus decreases if patients tilt the head. When treating the whole brain with head tilted, patients can acquire the same successful treatment Result and also preserve their valuable memory.

  2. Quantitative comparison of volumetric modulated arc therapy and intensity modulated radiotherapy plan quality in sino-nasal cancer

    International Nuclear Information System (INIS)

    Sankaralingam, Marimuthu; Glegg, Martin; Smith, Suzanne; James, Allan; Rizwanullah, Mohammed

    2012-01-01

    The aim of this study was to compare various dosimetric parameters of dynamic mlc intensity modulated radiotherapy (IMRT) plans with volumetric modulated arc therapy (VMAT) plans for sino-nasal cancers, which are rare and complex tumors to treat with radiotherapy. IMRT using five fields, coplanar in the sagittal plane and VMAT employing two coplanar arc plans were created for five patients. The plans were assessed by comparing Conformity Index and Sigma Index (dose homogeneity) in the Planning Target Volume (PTV) and through comparison of dose-volume characteristics to the following organs at risk (OARs): Spinal cord, brainstem, eye, ipsilateral and contralateral optic nerve and the volume of brain receiving 10% of the prescribed dose (V 10% ). The total monitor units required to deliver the plan were also compared. Conformity Index was found to be superior in VMAT plans for three patients and in IMRT plans for two patients. Dose homogeneity within the PTV was better with VMAT plans for all five cases. The mean difference in Sigma Index was 0.68%. There was no significant difference in dose between IMRT and VMAT plans for any of the OARs assessed in these patients. The monitor units were significantly reduced in the VMAT plan in comparison to the IMRT plan for four out of five patients, with mean reduction of 66%. It was found in this study that for the treatment of sino-nasal cancer, VMAT produced minimal, and statistically insignificant improvement in dose homogeneity within the PTV when compared with IMRT. VMAT plans were delivered using significantly fewer monitor units. We conclude in this study that VMAT does not offer significant improvement of treatment for sino-nasal cancer over the existing IMRT techniques, but the findings may change with a larger sample of patients in this rare condition. (author)

  3. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    Science.gov (United States)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-01-01

    Introduction Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. Methods A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. Results The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. Conclusion The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques. PMID:26229623

  4. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    International Nuclear Information System (INIS)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-01-01

    Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques

  5. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT).

    Science.gov (United States)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-12-01

    Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147-53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose-volume histogram (DVH) doses were consistently lower. The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques.

  6. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    Energy Technology Data Exchange (ETDEWEB)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham [Andrew Love Cancer Centre, Geelong Hospital, Geelong, Victoria (Australia)

    2013-12-15

    Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques.

  7. Multibeam tomotherapy: A new treatment unit devised for multileaf collimation, intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Achterberg, Nils; Mueller, Reinhold G.

    2007-01-01

    A fully integrated system for treatment planning, application, and verification for automated multileaf collimator (MLC) based, intensity-modulated, image-guided, and adaptive radiation therapy (IMRT, IGRT and ART, respectively) is proposed. Patient comfort, which was the major development goal, will be achieved through a new unit design and short treatment times. Our device for photon beam therapy will consist of a new dual energy linac with five fixed treatment heads positioned evenly along one plane but one electron beam generator only. A minimum of moving parts increases technical reliability and reduces motion times to a minimum. Motion is allowed solely for the MLCs, the robotic patient table, and the small angle gantry rotation of ±36 deg. . Besides sophisticated electron beam guidance, this compact setup can be built using existing modules. The flattening-filter-free treatment heads are characterized by reduced beam-on time and contain apertures restricted in one dimension to the area of maximum primary fluence output. In the case of longer targets, this leads to a topographic intensity modulation, thanks to the combination of ''step and shoot'' MLC delivery and discrete patient couch motion. Owing to the limited number of beam directions, this multislice cone beam serial tomotherapy is referred to as ''multibeam tomotherapy.'' Every patient slice is irradiated by one treatment head at any given moment but for one subfield only. The electron beam is then guided to the next head ready for delivery, while the other heads are preparing their leaves for the next segment. The ''Multifocal MLC-positioning'' algorithm was programmed to enable treatment planning and optimize treatment time. We developed an overlap strategy for the longitudinally adjacent fields of every beam direction, in doing so minimizing the field match problem and the effects of possible table step errors. Clinical case studies show for the same or better planning target volume coverage

  8. A Comparison of Helical Intensity-Modulated Radiotherapy, Intensity-Modulated Radiotherapy, and 3D-Conformal Radiation Therapy for Pancreatic Cancer

    International Nuclear Information System (INIS)

    Poppe, Matthew M.; Narra, Venkat; Yue, Ning J.; Zhou Jinghao; Nelson, Carl; Jabbour, Salma K.

    2011-01-01

    We assessed dosimetric differences in pancreatic cancer radiotherapy via helical intensity-modulated radiotherapy (HIMRT), linac-based IMRT, and 3D-conformal radiation therapy (3D-CRT) with regard to successful plan acceptance and dose to critical organs. Dosimetric analysis was performed in 16 pancreatic cases that were planned to 54 Gy; both post-pancreaticoduodenectomy (n = 8) and unresected (n = 8) cases were compared. Without volume modification, plans met constraints 75% of the time with HIMRT and IMRT and 13% with 3D-CRT. There was no statistically significantly improvement with HIMRT over conventional IMRT in reducing liver V35, stomach V45, or bowel V45. HIMRT offers improved planning target volume (PTV) dose homogeneity compared with IMRT, averaging a lower maximum dose and higher volume receiving the prescription dose (D100). HIMRT showed an increased mean dose over IMRT to bowel and liver. Both HIMRT and IMRT offer a statistically significant improvement over 3D-CRT in lowering dose to liver, stomach, and bowel. The results were similar for both unresected and resected patients. In pancreatic cancer, HIMRT offers improved dose homogeneity over conventional IMRT and several significant benefits to 3D-CRT. Factors to consider before incorporating IMRT into pancreatic cancer therapy are respiratory motion, dose inhomogeneity, and mean dose.

  9. Predictors of Dysgeusia in Patients With Oropharyngeal Cancer Treated With Chemotherapy and Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Sapir, Eli [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Tao, Yebin [Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States); Feng, Felix; Samuels, Stuart; El Naqa, Issam [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Murdoch-Kinch, Carol A. [School of Dentistry, University of Michigan, Ann Arbor, Michigan (United States); Feng, Mary [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Schipper, Matthew [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Department of Biostatistics, University of Michigan, Ann Arbor, Michigan (United States); Eisbruch, Avraham, E-mail: eisbruch@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States)

    2016-10-01

    Objective(s): Dysgeusia is a significant factor reducing quality of life and worsening dysphagia in patients receiving chemoradiation therapy for head and neck cancer. The factors affecting dysgeusia severity are uncertain. We investigated the effects on patient-reported dysgeusia of doses to the oral cavity, salivary output (required to dissolve food particles), and patient-reported xerostomia. Methods and Materials: Seventy-three patients with stage III to IV oropharyngeal cancer (OPC) (N=73) receiving definitive intensity modulated radiation therapy concurrently with chemotherapy participated in a prospective, longitudinal study of quality of life (QOL), including assessment of patient-reported gustatory function by taste-related questions from the Head and Neck QOL instrument (HNQOL) and the University of Washington Head and Neck-related QOL instrument (UWQOL), before therapy and periodically after treatment. At these intervals, patients also completed a validated xerostomia-specific questionnaire (XQ) and underwent unstimulated and stimulated major salivary gland flow rate measurements. Results: At 1, 3, 6, and 12 months after treatment, dysgeusia improved over time: severe dysgeusia was reported by 50%, 40%, 22%, and 23% of patients, respectively. Significant associations were found between patient-reported severe dysgeusia and radiation dose to the oral cavity (P=.005) and tongue (P=.019); normal tissue complication probability for severe dysgeusia at 3 months showed mean oral cavity D{sub 50} doses 53 Gy and 57 Gy in the HNQOL and WUQOL questionnaires, respectively, with curve slope (m) of 0.41. Measured salivary output was not statistically significantly correlated with severe taste dysfunction, whereas patient-reported XQ summary scores and xerostomia while eating scores were correlated with severe dysgeusia in the UWQOL tool (P=.04). Conclusions: Taste impairment is significantly correlated with mean radiation dose to the oral cavity. Patient

  10. Predictors of Dysgeusia in Patients With Oropharyngeal Cancer Treated With Chemotherapy and Intensity Modulated Radiation Therapy

    International Nuclear Information System (INIS)

    Sapir, Eli; Tao, Yebin; Feng, Felix; Samuels, Stuart; El Naqa, Issam; Murdoch-Kinch, Carol A.; Feng, Mary; Schipper, Matthew; Eisbruch, Avraham

    2016-01-01

    Objective(s): Dysgeusia is a significant factor reducing quality of life and worsening dysphagia in patients receiving chemoradiation therapy for head and neck cancer. The factors affecting dysgeusia severity are uncertain. We investigated the effects on patient-reported dysgeusia of doses to the oral cavity, salivary output (required to dissolve food particles), and patient-reported xerostomia. Methods and Materials: Seventy-three patients with stage III to IV oropharyngeal cancer (OPC) (N=73) receiving definitive intensity modulated radiation therapy concurrently with chemotherapy participated in a prospective, longitudinal study of quality of life (QOL), including assessment of patient-reported gustatory function by taste-related questions from the Head and Neck QOL instrument (HNQOL) and the University of Washington Head and Neck-related QOL instrument (UWQOL), before therapy and periodically after treatment. At these intervals, patients also completed a validated xerostomia-specific questionnaire (XQ) and underwent unstimulated and stimulated major salivary gland flow rate measurements. Results: At 1, 3, 6, and 12 months after treatment, dysgeusia improved over time: severe dysgeusia was reported by 50%, 40%, 22%, and 23% of patients, respectively. Significant associations were found between patient-reported severe dysgeusia and radiation dose to the oral cavity (P=.005) and tongue (P=.019); normal tissue complication probability for severe dysgeusia at 3 months showed mean oral cavity D_5_0 doses 53 Gy and 57 Gy in the HNQOL and WUQOL questionnaires, respectively, with curve slope (m) of 0.41. Measured salivary output was not statistically significantly correlated with severe taste dysfunction, whereas patient-reported XQ summary scores and xerostomia while eating scores were correlated with severe dysgeusia in the UWQOL tool (P=.04). Conclusions: Taste impairment is significantly correlated with mean radiation dose to the oral cavity. Patient

  11. Bile Acid Malabsorption After Pelvic and Prostate Intensity Modulated Radiation Therapy: An Uncommon but Treatable Condition

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Victoria [Academic Urology Unit, Institute of Cancer Research and The Royal Marsden Hospital, London and Sutton (United Kingdom); Benton, Barbara [Gastroenterology Unit, Institute of Cancer Research and The Royal Marsden Hospital, London and Sutton (United Kingdom); Sohaib, Aslam [Department of Radiology, Institute of Cancer Research and The Royal Marsden Hospital, London and Sutton (United Kingdom); Dearnaley, David [Academic Urology Unit, Institute of Cancer Research and The Royal Marsden Hospital, London and Sutton (United Kingdom); Andreyev, H. Jervoise N., E-mail: j@andreyev.demon.co.uk [Gastroenterology Unit, Institute of Cancer Research and The Royal Marsden Hospital, London and Sutton (United Kingdom)

    2012-12-01

    Purpose: Intensity modulated radiation therapy (IMRT) is a significant therapeutic advance in prostate cancer, allowing increased tumor dose delivery and increased sparing of normal tissues. IMRT planning uses strict dose constraints to nearby organs to limit toxicity. Bile acid malabsorption (BAM) is a treatable disorder of the terminal ileum (TI) that presents with symptoms similar to radiation therapy toxicity. It has not been described in patients receiving RT for prostate cancer in the contemporary era. We describe new-onset BAM in men after IMRT for prostate cancer. Methods and Materials: Diagnosis of new-onset BAM was established after typical symptoms developed, selenium-75 homocholic acid taurine (SeHCAT) scanning showed 7-day retention of <15%, and patients' symptoms unequivocally responded to a bile acid sequestrant. The TI was identified on the original radiation therapy plan, and the radiation dose delivered was calculated and compared with accepted dose-volume constraints. Results: Five of 423 men treated in a prospective series of high-dose prostate and pelvic IMRT were identified with new onset BAM (median age, 65 years old). All reported having normal bowel habits before RT. The volume of TI ranged from 26-141 cc. The radiation dose received by the TI varied between 11.4 Gy and 62.1 Gy (uncorrected). Three of 5 patients had TI treated in excess of 45 Gy (equivalent dose calculated in 2-Gy fractions, using an {alpha}/{beta} ratio of 3) with volumes ranging from 1.6 cc-49.0 cc. One patient had mild BAM (SeHCAT retention, 10%-15%), 2 had moderate BAM (SeHCAT retention, 5%-10%), and 2 had severe BAM (SeHCAT retention, <5%). The 3 patients whose TI received {>=}45 Gy developed moderate to severe BAM, whereas those whose TI received <45 Gy had only mild to moderate BAM. Conclusions: Radiation delivered to the TI during IMRT may cause BAM. Identification of the TI from unenhanced RT planning computed tomography scans is difficult and may impede

  12. Density overwrites of internal tumor volumes in intensity modulated proton therapy plans for mobile lung tumors

    Science.gov (United States)

    Botas, Pablo; Grassberger, Clemens; Sharp, Gregory; Paganetti, Harald

    2018-02-01

    The purpose of this study was to investigate internal tumor volume density overwrite strategies to minimize intensity modulated proton therapy (IMPT) plan degradation of mobile lung tumors. Four planning paradigms were compared for nine lung cancer patients. Internal gross tumor volume (IGTV) and internal clinical target volume (ICTV) structures were defined encompassing their respective volumes in every 4DCT phase. The paradigms use different planning CT (pCT) created from the average intensity projection (AIP) of the 4DCT, overwriting the density within the IGTV to account for movement. The density overwrites were: (a) constant filling with 100 HU (C100) or (b) 50 HU (C50), (c) maximum intensity projection (MIP) across phases, and (d) water equivalent path length (WEPL) consideration from beam’s-eye-view. Plans were created optimizing dose-influence matrices calculated with fast GPU Monte Carlo (MC) simulations in each pCT. Plans were evaluated with MC on the 4DCTs using a model of the beam delivery time structure. Dose accumulation was performed using deformable image registration. Interplay effect was addressed applying 10 times rescanning. Significantly less DVH metrics degradation occurred when using MIP and WEPL approaches. Target coverage (D99≥slant 70 Gy(RBE)) was fulfilled in most cases with MIP and WEPL (D{{99}WEPL}=69.2+/- 4.0 Gy (RBE)), keeping dose heterogeneity low (D5-D{{95}WEPL}=3.9+/- 2.0 Gy(RBE)). The mean lung dose was kept lowest by the WEPL strategy, as well as the maximum dose to organs at risk (OARs). The impact on dose levels in the heart, spinal cord and esophagus were patient specific. Overall, the WEPL strategy gives the best performance and should be preferred when using a 3D static geometry for lung cancer IMPT treatment planning. Newly available fast MC methods make it possible to handle long simulations based on 4D data sets to perform studies with high accuracy and efficiency, even prior to individual treatment planning.

  13. 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.

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

    International Nuclear Information System (INIS)

    Gunther, Jillian R.; Sato, Mariko; Chintagumpala, Murali; Ketonen, Leena; Jones, Jeremy Y.; Allen, Pamela K.; Paulino, Arnold C.; Okcu, M. Fatih; Su, Jack M.; Weinberg, Jeffrey; Boehling, Nicholas S.; Khatua, Soumen; Adesina, Adekunle; Dauser, Robert; Whitehead, William E.; Mahajan, Anita

    2015-01-01

    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

  15. Outcome of three-dimensional conformal radiation therapy and intensity-modulated radiation therapy for inoperable locally advanced pancreatic cancer

    International Nuclear Information System (INIS)

    Lu Ningning; Jin Jing; Li Yexiong; Yu Zihao; Liu Xinfan; Wang Weihu; Wang Shulian; Song Yongwen; Liu Yuping

    2009-01-01

    Objective: To evaluate the outcome of radiotherapy for locally advanced pancreatic cancer. Methods: From January 2000 to December 2007, 41 patients with inoperable locally advanced (stage III) pancreatic cancer were treated with three-dimensional conformal radiation therapy(3DCRT) or intensity-modulated radiation therapy (IMRT). Among these patients, 30 received concurrent radio-chemo-therapy. Results: The median survival time(MST) and 1-year overall survival were 9.2 months and 23%. Patients with pretreatment KPS ≥ 80, no regional lymph nodes metastasis, and CR/PR after radiotherapy had better prognosis. The corresponding MSTs were 11.1 months vs 5.8 months (χ 2 =7.50, P=0.006), 10.8 months vs 6.5 months(χ 2 =5.67, P=0.017), and 19.5 months vs 9.1 months (χ 2 =7.28, P=0.007), respectively. Concurrent radio-chemotherapy tended to improve the overall survival(χ 2 =3.25, P=0.072). After radiotherapy, 18 patients had clinical benefit response, mainly being abdominal pain relief. Neither grade 4 hematologic nor grade 3 non-hematologic toxicities were observed. Conclusions: For patients with locally advanced pancreatic cancer, both 3DCRT and IMRT are effective in alleviation of disease-related symptoms. Patients with better performance status before treatment, no regional lymph nodes metastasis, and better response to radiotherapy may have better prognosis. Concurrent radio-chemotherapy trend to improve overall survival when compared with radiotherapy alone. (authors)

  16. Intensity modulated radiation-therapy for preoperative posterior abdominal wall irradiation of retroperitoneal liposarcomas

    International Nuclear Information System (INIS)

    Bossi, Alberto; De Wever, Ivo; Van Limbergen, Erik; Vanstraelen, Bianca

    2007-01-01

    Purpose: Preoperative external-beam radiation therapy (preop RT) in the management of Retroperitoneal Liposarcomas (RPLS) typically involves the delivery of radiation to the entire tumor mass: yet this may not be necessary. The purpose of this study is to evaluate a new strategy of preop RT for RPLS in which the target volume is limited to the contact area between the tumoral mass and the posterior abdominal wall. Methods and Materials: Between June 2000 and Jan 2005, 18 patients with the diagnosis of RPLS have been treated following a pilot protocol of pre-op RT, 50 Gy in 25 fractions of 2 Gy/day. The Clinical Target Volume (CTV) has been limited to the posterior abdominal wall, region at higher risk for local relapse. A Three-Dimensional conformal (3D-CRT) and an Intensity Modulated (IMRT) plan were generated and compared; toxicity was reported following the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events v3.0. Results: All patients completed the planned treatment and the acute toxicity was tolerable: 2 patients experienced Grade 3 and 1 Grade 2 anorexia while 2 patients developed Grade 2 nausea. IMRT allows a better sparing of the ipsilateral and the contralateral kidney. All tumors were successfully resected without major complications. At a median follow-up of 27 months 2 patients developed a local relapse and 1 lung metastasis. Conclusions: Our strategy of preop RT is feasible and well tolerated: the rate of resectability is not compromised by limiting the preop CTV to the posterior abdominal wall and a better critical-structures sparing is obtained with IMRT

  17. Intensity-modulated radiation therapy for T4 nasopharyngeal carcinoma. Treatment results and locoregional

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.L.Y.; Tsai, C.L.; Chen, W.Y.; Wang, C.W. [National Taiwan Univ. Hospital, Taipei (China). Div. of Radiation Oncology; Huang, Y.S.; Chen, Y.F. [National Taiwan Univ. Hospital, Taipei (China). Dept. of Medical Imaging; Kuo, S.H. [National Taiwan Univ. Hospital, Taipei (China). Div. of Radiation Oncology; National Taiwan Univ. College of Medicine, Taipei (China). Graduate Inst. of Clinical Medicine; Hong, R.L. [National Taiwan Univ. Hospital, Taipei (China). Div. of Medical Oncology; Ko, J.Y.; Lou, P.J. [National Taiwan Univ. Hospital, Taipei (China). Dept. of Otolaryngology

    2013-12-15

    Purpose: The purpose of this work was to examine outcomes in patients with T4 nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). Methods and materials: Between 2007 and 2010, 154 patients with nonmetastatic T4 NPC were treated with IMRT to a total dose of 70 Gy in 33-35 fractions. In addition, 97 % of patients received concurrent platinum-based chemotherapy. The median follow-up time was 52.8 months. Results: The rates of 5-year actuarial locoregional control, distant metastasis-free survival, progression free-survival, and overall survival (OS) were 81.2, 72.2, 61.9, and 78.1 %, respectively. A total of 27 patients had locoregional recurrence: 85.2 % in-field failures, 11.1 % marginal failures, and 3.7 % out-of-field failures. Fourteen patients with locoregional recurrence received aggressive treatments, including nasopharyngectomy, neck dissection, or re-irradiation, and the 5-year OS rate tended to be better (61.9 %) compared to those receiving conservative treatment (32.0 %, p = 0.051). In patients treated with 1 course of radiotherapy, grade {>=} 3 toxicities of ototoxicity, neck fibrosis, xerostomia, epistaxis, and radiographic temporal lobe necrosis occurred in 18.2, 9.8, 6.3, 2.1, and 5.6 % of patients, respectively. Increased ototoxicity, osteonecrosis, severe nasal bleeding, and temporal necrosis were observed in patients treated by re-irradiation. Conclusion: IMRT offers good locoregional control in patients with T4 NPC. For patients with locoregional recurrence after definitive radiotherapy, aggressive local treatment may be considered for a better outcome. (orig.)

  18. Dosimetric predictors of hypothyroidism in oropharyngeal cancer patients treated with intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Chyan, Arthur; Chen, Josephine; Shugard, Erin; Lambert, Louise; Quivey, Jeanne M; Yom, Sue S

    2014-01-01

    Radiation to the neck has long been associated with an elevated risk of hypothyroidism development. The goal of the present work is to define dosimetric predictors of hypothyroidism in oropharyngeal cancer (OPC) patients treated with intensity-modulated radiation therapy. Data for 123 patients, with a median follow up of 4.6 years, were retrospectively analyzed. Patients with elevated thyroid-stimulating hormone levels or with a clinical diagnosis were categorized as hypothyroid. Patient demographic parameters, thyroid volume, mean thyroid dose, the percent of thyroid volume receiving minimum specified dose levels (VxxGy), and the absolute thyroid volume spared from specified dose levels (VSxxGy) were analyzed. Normal-tissue complication probability (NTCP) was also calculated using several recently published models. Thyroid volume and many radiation dosimetric parameters were statistically different in the hypothyroid group. For the patients with initial thyroid volumes of 8 cc or greater, several dosimetric parameters were found to define subgroups at statistically significant lower risk of developing hypothyroidism. Patients with VS45 Gy of at least 3 cc, VS50 Gy at least 5 cc, VS50 Gy at least 6 cc, V50 Gy below 45%, V50 Gy below 55%, or mean thyroid dose below 49 Gy had a 28-38% estimated risk of hypothyroidism at 3 years compared to a 55% risk for the entire study group. Patients with a NTCP of less than 0.75 or 0.8, calculated using recently published models, were also observed to have a lower risk of developing hypothyroidism. Based on long-term follow up data for OPC patients treated with IMRT, we recommend plan optimization objectives to reduce the volume of thyroid receiving over 45 Gy to significantly decrease the risk of developing hypothyroidism. The online version of this article (doi:10.1186/s13014-014-0269-4) contains supplementary material, which is available to authorized users

  19. Automation and Intensity Modulated Radiation Therapy for Individualized High-Quality Tangent Breast Treatment Plans

    International Nuclear Information System (INIS)

    Purdie, Thomas G.; Dinniwell, Robert E.; Fyles, Anthony; Sharpe, Michael B.

    2014-01-01

    Purpose: To demonstrate the large-scale clinical implementation and performance of an automated treatment planning methodology for tangential breast intensity modulated radiation therapy (IMRT). Methods and Materials: Automated planning was used to prospectively plan tangential breast IMRT treatment for 1661 patients between June 2009 and November 2012. The automated planning method emulates the manual steps performed by the user during treatment planning, including anatomical segmentation, beam placement, optimization, dose calculation, and plan documentation. The user specifies clinical requirements of the plan to be generated through a user interface embedded in the planning system. The automated method uses heuristic algorithms to define and simplify the technical aspects of the treatment planning process. Results: Automated planning was used in 1661 of 1708 patients receiving tangential breast IMRT during the time interval studied. Therefore, automated planning was applicable in greater than 97% of cases. The time for treatment planning using the automated process is routinely 5 to 6 minutes on standard commercially available planning hardware. We have shown a consistent reduction in plan rejections from plan reviews through the standard quality control process or weekly quality review multidisciplinary breast rounds as we have automated the planning process for tangential breast IMRT. Clinical plan acceptance increased from 97.3% using our previous semiautomated inverse method to 98.9% using the fully automated method. Conclusions: Automation has become the routine standard method for treatment planning of tangential breast IMRT at our institution and is clinically feasible on a large scale. The method has wide clinical applicability and can add tremendous efficiency, standardization, and quality to the current treatment planning process. The use of automated methods can allow centers to more rapidly adopt IMRT and enhance access to the documented

  20. Pertinence analysis of intensity-modulated radiation therapy dosimetry error and parameters of beams

    International Nuclear Information System (INIS)

    Chi Zifeng; Liu Dan; Cao Yankun; Li Runxiao; Han Chun

    2012-01-01

    Objective: To study the relationship between parameter settings in the intensity-modulated radiation therapy (IMRT) planning in order to explore the effect of parameters on absolute dose verification. Methods: Forty-three esophageal carcinoma cases were optimized with Pinnacle 7.6c by experienced physicist using appropriate optimization parameters and dose constraints with a number of iterations to meet the clinical acceptance criteria. The plans were copied to water-phantom, 0.13 cc ion Farmer chamber and DOSE1 dosimeter was used to measure the absolute dose. The statistical data of the parameters of beams for the 43 cases were collected, and the relationships among them were analyzed. The statistical data of the dosimetry error were collected, and comparative analysis was made for the relation between the parameters of beams and ion chamber absolute dose verification results. Results: The parameters of beams were correlated among each other. Obvious affiliation existed between the dose accuracy and parameter settings. When the beam segment number of IMRT plan was more than 80, the dose deviation would be greater than 3%; however, if the beam segment number was less than 80, the dose deviation was smaller than 3%. When the beam segment number was more than 100, part of the dose deviation of this plan was greater than 4%. On the contrary, if the beam segment number was less than 100, the dose deviation was smaller than 4% definitely. Conclusions: In order to decrease the absolute dose verification error, less beam angles and less beam segments are needed and the beam segment number should be controlled within the range of 80. (authors)

  1. An Anatomically Validated Brachial Plexus Contouring Method for Intensity Modulated Radiation Therapy Planning

    International Nuclear Information System (INIS)

    Van de Velde, Joris; Audenaert, Emmanuel; Speleers, Bruno; Vercauteren, Tom; Mulliez, Thomas; Vandemaele, Pieter; Achten, Eric; Kerckaert, Ingrid; D'Herde, Katharina; De Neve, Wilfried; Van Hoof, Tom

    2013-01-01

    Purpose: To develop contouring guidelines for the brachial plexus (BP) using anatomically validated cadaver datasets. Magnetic resonance imaging (MRI) and computed tomography (CT) were used to obtain detailed visualizations of the BP region, with the goal of achieving maximal inclusion of the actual BP in a small contoured volume while also accommodating for anatomic variations. Methods and Materials: CT and MRI were obtained for 8 cadavers positioned for intensity modulated radiation therapy. 3-dimensional reconstructions of soft tissue (from MRI) and bone (from CT) were combined to create 8 separate enhanced CT project files. Dissection of the corresponding cadavers anatomically validated the reconstructions created. Seven enhanced CT project files were then automatically fitted, separately in different regions, to obtain a single dataset of superimposed BP regions that incorporated anatomic variations. From this dataset, improved BP contouring guidelines were developed. These guidelines were then applied to the 7 original CT project files and also to 1 additional file, left out from the superimposing procedure. The percentage of BP inclusion was compared with the published guidelines. Results: The anatomic validation procedure showed a high level of conformity for the BP regions examined between the 3-dimensional reconstructions generated and the dissected counterparts. Accurate and detailed BP contouring guidelines were developed, which provided corresponding guidance for each level in a clinical dataset. An average margin of 4.7 mm around the anatomically validated BP contour is sufficient to accommodate for anatomic variations. Using the new guidelines, 100% inclusion of the BP was achieved, compared with a mean inclusion of 37.75% when published guidelines were applied. Conclusion: Improved guidelines for BP delineation were developed using combined MRI and CT imaging with validation by anatomic dissection

  2. Application of influence diagrams to prostate intensity-modulated radiation therapy plan selection

    International Nuclear Information System (INIS)

    Meyer, Juergen; Phillips, Mark H; Cho, Paul S; Kalet, Ira; Doctor, Jason N

    2004-01-01

    The purpose is to incorporate clinically relevant factors such as patient-specific and dosimetric information as well as data from clinical trials in the decision-making process for the selection of prostate intensity-modulated radiation therapy (IMRT) plans. The approach is to incorporate the decision theoretic concept of an influence diagram into the solution of the multiobjective optimization inverse planning problem. A set of candidate IMRT plans was obtained by varying the importance factors for the planning target volume (PTV) and the organ-at-risk (OAR) in combination with simulated annealing to explore a large part of the solution space. The Pareto set for the PTV and OAR was analysed to demonstrate how the selection of the weighting factors influenced which part of the solution space was explored. An influence diagram based on a Bayesian network with 18 nodes was designed to model the decision process for plan selection. The model possessed nodes for clinical laboratory results, tumour grading, staging information, patient-specific information, dosimetric information, complications and survival statistics from clinical studies. A utility node was utilized for the decision-making process. The influence diagram successfully ranked the plans based on the available information. Sensitivity analyses were used to judge the reasonableness of the diagram and the results. In conclusion, influence diagrams lend themselves well to modelling the decision processes for IMRT plan selection. They provide an excellent means to incorporate the probabilistic nature of data and beliefs into one model. They also provide a means for introducing evidence-based medicine, in the form of results of clinical trials, into the decision-making process

  3. Intensity Modulated Radiation Therapy with Simultaneously Integrated Boost at University Hospital Centre Zagreb (KBC Zagreb)

    International Nuclear Information System (INIS)

    Barisic, L.; Bibic, J.; Grego, T.; Hrsak, H.; Kovacevic, N.

    2013-01-01

    Intensity Modulated Radiation Therapy technique (IMRT) is state of art in modern radiotherapy for bilateral Head and Neck (H and N) malignancies. IMRT of real patients is implemented at KBC Zagreb since June 2012. Our method is inspired partly by Hull IMRT technique. It differs from standard IMRT beam layout (7 beams, gantry angles in 51° steps) and it avoids direct irradiation of OARs. We also use simultaneous integrated boost (SIB IMRT) fractionation. The aim of this paper is to present in some details the whole process of our SIB IMRT including plan quality assurance. Results for several patients together with comparison with ConPas and standard IMRT are presented. In our department, in last several years, routine method for H and N cancer RT was ConPas. During this period we (together with ConPas plans) produced standard IMRT plans with seven equidistant fields for actual patients. Our comparative analysis showed clear superiority of IMRT over ConPas for H and N radiotherapy. Since spring 2012 we have produced also non-standard IMRT plans that are based on Hull (U.K.) experience, with beam gantry angles at 0, 50, 80, 150, 210, 280 and 310 degrees. Also, in this method, direct irradiation of OARs (particularly spinal cord) is avoided by shielding as initial constraint. This approach proved to be better than standard IMRT in all analyzed cases. Having all this in mind, we decided to implement 'our' IMRT technique on real patients. Second essential point of our method is SIB fractionation. It has dosimetric, logistic and radiobiological advantages over standard fractionation. IMRT plan QA is routinely performed using Seven29 and Gamma index method. We take 3 mm/3 % Gamma index and 85 % of passed points as passing rate.(author)

  4. Improvement of dose distributions in abutment regions of intensity modulated radiation therapy and electron fields

    International Nuclear Information System (INIS)

    Dogan, Nesrin; Leybovich, Leonid B.; Sethi, Anil; Emami, Bahman

    2002-01-01

    In recent years, intensity modulated radiation therapy (IMRT) is used to radiate tumors that are in close proximity to vital organs. Targets consisting of a deep-seated region followed by a superficial one may be treated with abutting photon and electron fields. However, no systematic study regarding matching of IMRT and electron beams was reported. In this work, a study of dose distributions in the abutment region between tomographic and step-and-shoot IMRT and electron fields was carried out. A method that significantly improves dose homogeneity between abutting tomographic IMRT and electron fields was developed and tested. In this method, a target region that is covered by IMRT was extended into the superficial target area by ∼2.0 cm. The length and shape of IMRT target extension was chosen such that high isodose lines bent away from the region treated by the electrons. This reduced the magnitude of hot spots caused by the 'bulging effect' of electron field penumbra. To account for the uncertainties in positioning of the IMRT and electron fields, electron field penumbra was modified using conventional (photon) multileaf collimator (MLC). The electron beam was delivered in two steps: half of the dose delivered with MLCs in retracted position and another half with MLCs extended to the edge of electron field that abuts tomographic IMRT field. The experimental testing of this method using film dosimetry has demonstrated that the magnitude of the hot spots was reduced from ∼45% to ∼5% of the prescription dose. When an error of ±1.5 mm in field positioning was introduced, the dose inhomogeneity in the abutment region did not exceed ±15% of the prescription dose. With step-and-shoot IMRT, the most homogeneous dose distribution was achieved when there was a 3 mm gap between the IMRT and electron fields

  5. Multi-GPU configuration of 4D intensity modulated radiation therapy inverse planning using global optimization

    Science.gov (United States)

    Hagan, Aaron; Sawant, Amit; Folkerts, Michael; Modiri, Arezoo

    2018-01-01

    We report on the design, implementation and characterization of a multi-graphic processing unit (GPU) computational platform for higher-order optimization in radiotherapy treatment planning. In collaboration with a commercial vendor (Varian Medical Systems, Palo Alto, CA), a research prototype GPU-enabled Eclipse (V13.6) workstation was configured. The hardware consisted of dual 8-core Xeon processors, 256 GB RAM and four NVIDIA Tesla K80 general purpose GPUs. We demonstrate the utility of this platform for large radiotherapy optimization problems through the development and characterization of a parallelized particle swarm optimization (PSO) four dimensional (4D) intensity modulated radiation therapy (IMRT) technique. The PSO engine was coupled to the Eclipse treatment planning system via a vendor-provided scripting interface. Specific challenges addressed in this implementation were (i) data management and (ii) non-uniform memory access (NUMA). For the former, we alternated between parameters over which the computation process was parallelized. For the latter, we reduced the amount of data required to be transferred over the NUMA bridge. The datasets examined in this study were approximately 300 GB in size, including 4D computed tomography images, anatomical structure contours and dose deposition matrices. For evaluation, we created a 4D-IMRT treatment plan for one lung cancer patient and analyzed computation speed while varying several parameters (number of respiratory phases, GPUs, PSO particles, and data matrix sizes). The optimized 4D-IMRT plan enhanced sparing of organs at risk by an average reduction of 26% in maximum dose, compared to the clinical optimized IMRT plan, where the internal target volume was used. We validated our computation time analyses in two additional cases. The computation speed in our implementation did not monotonically increase with the number of GPUs. The optimal number of GPUs (five, in our study) is directly related to the

  6. Reirradiation of Head and Neck Cancers With Intensity Modulated Radiation Therapy: Outcomes and Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Takiar, Vinita [Department of Radiation Oncology, University of Cincinnati, Cincinnati, Ohio (United States); Garden, Adam S.; Ma, Dominic; Morrison, William H.; Edson, Mark [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zafereo, Mark E. [Department of Surgical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gunn, Gary B.; Fuller, Clifton D.; Beadle, Beth; Frank, Steven J. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); William, William N.; Kies, Merrill [Department of Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); El-Naggar, Adel K. [Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Weber, Randal [Department of Surgical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Rosenthal, David I. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Phan, Jack, E-mail: jphan@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2016-07-15

    Purpose: To review our 15-year institutional experience using intensity modulated radiation therapy (IMRT) to reirradiate patients with head and neck squamous cell carcinomas (HNSCC) and identify predictors of outcomes and toxicity. Methods and Materials: We retrospectively reviewed the records of 227 patients who received head and neck reirradiation using IMRT from 1999 to 2014. Patients treated with noncurative intent were excluded. Radiation-related acute and late toxicities were recorded. Prognostic variables included performance status, disease site, disease-free interval, chemotherapy, and RT dose and volume. Correlative analyses were performed separately for surgery and nonsurgery patients. Results: Two hundred six patients (91%) were retreated with curative intent, and 173 had HNSCC histology; 104 (50%) underwent salvage resection, and 135 (66%) received chemotherapy. Median follow-up after reirradiation was 24.7 months. Clinical outcomes were worse for HNSCC patients, with 5-year locoregional control, progression-free survival, and overall survival rates of 53%, 22%, and 32%, respectively, compared with 74%, 59%, and 79%, respectively, for non-HNSCC patients. On multivariate analysis, concurrent chemotherapy and retreatment site were associated with tumor control, whereas performance status was associated with survival. Favorable prognostic factors specific to surgery patients were neck retreatment and lack of extracapsular extension, whereas for nonsurgery patients, these were a nasopharynx subsite and complete response to induction chemotherapy. Actuarial rates of grade ≥3 toxicity were 32% at 2 years and 48% at 5 years, with dysphagia or odynophagia being most common. Increased grade ≥3 toxicity was associated with retreatment volume >50 cm{sup 3} and concurrent chemotherapy. Conclusions: Reirradiation with IMRT either definitively or after salvage surgery can produce promising local control and survival in selected patients with head and neck

  7. A critical evaluation of worst case optimization methods for robust intensity-modulated proton therapy planning

    International Nuclear Information System (INIS)

    Fredriksson, Albin; Bokrantz, Rasmus

    2014-01-01

    Purpose: To critically evaluate and compare three worst case optimization methods that have been previously employed to generate intensity-modulated proton therapy treatment plans that are robust against systematic errors. The goal of the evaluation is to identify circumstances when the methods behave differently and to describe the mechanism behind the differences when they occur. Methods: The worst case methods optimize plans to perform as well as possible under the worst case scenario that can physically occur (composite worst case), the combination of the worst case scenarios for each objective constituent considered independently (objectivewise worst case), and the combination of the worst case scenarios for each voxel considered independently (voxelwise worst case). These three methods were assessed with respect to treatment planning for prostate under systematic setup uncertainty. An equivalence with probabilistic optimization was used to identify the scenarios that determine the outcome of the optimization. Results: If the conflict between target coverage and normal tissue sparing is small and no dose-volume histogram (DVH) constraints are present, then all three methods yield robust plans. Otherwise, they all have their shortcomings: Composite worst case led to unnecessarily low plan quality in boundary scenarios that were less difficult than the worst case ones. Objectivewise worst case generally led to nonrobust plans. Voxelwise worst case led to overly conservative plans with respect to DVH constraints, which resulted in excessive dose to normal tissue, and less sharp dose fall-off than the other two methods. Conclusions: The three worst case methods have clearly different behaviors. These behaviors can be understood from which scenarios that are active in the optimization. No particular method is superior to the others under all circumstances: composite worst case is suitable if the conflicts are not very severe or there are DVH constraints whereas

  8. Beam orientation optimization for intensity modulated radiation therapy using adaptive l2,1-minimization

    International Nuclear Information System (INIS)

    Jia Xun; Men Chunhua; Jiang, Steve B; Lou Yifei

    2011-01-01

    Beam orientation optimization (BOO) is a key component in the process of intensity modulated radiation therapy treatment planning. It determines to what degree one can achieve a good treatment plan in the subsequent plan optimization process. In this paper, we have developed a BOO algorithm via adaptive l 2,1 -minimization. Specifically, we introduce a sparsity objective function term into our model which contains weighting factors for each beam angle adaptively adjusted during the optimization process. Such an objective function favors a small number of beam angles. By optimizing a total objective function consisting of a dosimetric term and the sparsity term, we are able to identify unimportant beam angles and gradually remove them without largely sacrificing the dosimetric objective. In one typical prostate case, the convergence property of our algorithm, as well as how beam angles are selected during the optimization process, is demonstrated. Fluence map optimization (FMO) is then performed based on the optimized beam angles. The resulting plan quality is presented and is found to be better than that of equiangular beam orientations. We have further systematically validated our algorithm in the contexts of 5-9 coplanar beams for five prostate cases and one head and neck case. For each case, the final FMO objective function value is used to compare the optimized beam orientations with the equiangular ones. It is found that, in the majority of cases tested, our BOO algorithm leads to beam configurations which attain lower FMO objective function values than those of corresponding equiangular cases, indicating the effectiveness of our BOO algorithm. Superior plan qualities are also demonstrated by comparing DVH curves between BOO plans and equiangular plans.

  9. Automatically-generated rectal dose constraints in intensity-modulated radiation therapy for prostate cancer

    Science.gov (United States)

    Hwang, Taejin; Kim, Yong Nam; Kim, Soo Kon; Kang, Sei-Kwon; Cheong, Kwang-Ho; Park, Soah; Yoon, Jai-Woong; Han, Taejin; Kim, Haeyoung; Lee, Meyeon; Kim, Kyoung-Joo; Bae, Hoonsik; Suh, Tae-Suk

    2015-06-01

    The dose constraint during prostate intensity-modulated radiation therapy (IMRT) optimization should be patient-specific for better rectum sparing. The aims of this study are to suggest a novel method for automatically generating a patient-specific dose constraint by using an experience-based dose volume histogram (DVH) of the rectum and to evaluate the potential of such a dose constraint qualitatively. The normal tissue complication probabilities (NTCPs) of the rectum with respect to V %ratio in our study were divided into three groups, where V %ratio was defined as the percent ratio of the rectal volume overlapping the planning target volume (PTV) to the rectal volume: (1) the rectal NTCPs in the previous study (clinical data), (2) those statistically generated by using the standard normal distribution (calculated data), and (3) those generated by combining the calculated data and the clinical data (mixed data). In the calculated data, a random number whose mean value was on the fitted curve described in the clinical data and whose standard deviation was 1% was generated by using the `randn' function in the MATLAB program and was used. For each group, we validated whether the probability density function (PDF) of the rectal NTCP could be automatically generated with the density estimation method by using a Gaussian kernel. The results revealed that the rectal NTCP probability increased in proportion to V %ratio , that the predictive rectal NTCP was patient-specific, and that the starting point of IMRT optimization for the given patient might be different. The PDF of the rectal NTCP was obtained automatically for each group except that the smoothness of the probability distribution increased with increasing number of data and with increasing window width. We showed that during the prostate IMRT optimization, the patient-specific dose constraints could be automatically generated and that our method could reduce the IMRT optimization time as well as maintain the

  10. Planning Hybrid Intensity Modulated Radiation Therapy for Whole-breast Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Farace, Paolo [Medical Physics Department, Regional Oncological Hospital, Cagliari (Italy); Zucca, Sergio; Solla, Ignazio; Fadda, Giuseppina; Durzu, Silvia; Porru, Sergio; Meleddu, Gianfranco [Medical Physics Department, Regional Oncological Hospital, Cagliari (Italy); Deidda, Maria Assunta; Possanzini, Marco; Orru, Sivia; Lay, Giancarlo [Radiotherapy Department, Regional Oncological Hospital, Cagliari (Italy)

    2012-09-01

    Purpose: To test tangential and not-tangential hybrid intensity modulated radiation therapy (IMRT) for whole-breast irradiation. Methods and Materials: Seventy-eight (36 right-, 42 left-) breast patients were randomly selected. Hybrid IMRT was performed by direct aperture optimization. A semiautomated method for planning hybrid IMRT was implemented using Pinnacle scripts. A plan optimization volume (POV), defined as the portion of the planning target volume covered by the open beams, was used as the target objective during inverse planning. Treatment goals were to prescribe a minimum dose of 47.5 Gy to greater than 90% of the POV and to minimize the POV and/or normal tissue receiving a dose greater than 107%. When treatment goals were not achieved by using a 4-field technique (2 conventional open plus 2 IMRT tangents), a 6-field technique was applied, adding 2 non tangential (anterior-oblique) IMRT beams. Results: Using scripts, manual procedures were minimized (choice of optimal beam angle, setting monitor units for open tangentials, and POV definition). Treatment goals were achieved by using the 4-field technique in 61 of 78 (78%) patients. The 6-field technique was applied in the remaining 17 of 78 (22%) patients, allowing for significantly better achievement of goals, at the expense of an increase of low-dose ({approx}5 Gy) distribution in the contralateral tissue, heart, and lungs but with no significant increase of higher doses ({approx}20 Gy) in heart and lungs. The mean monitor unit contribution to IMRT beams was significantly greater (18.7% vs 9.9%) in the group of patients who required 6-field procedure. Conclusions: Because hybrid IMRT can be performed semiautomatically, it can be planned for a large number of patients with little impact on human or departmental resources, promoting it as the standard practice for whole-breast irradiation.

  11. Planning hybrid intensity modulated radiation therapy for whole-breast irradiation.

    Science.gov (United States)

    Farace, Paolo; Zucca, Sergio; Solla, Ignazio; Fadda, Giuseppina; Durzu, Silvia; Porru, Sergio; Meleddu, Gianfranco; Deidda, Maria Assunta; Possanzini, Marco; Orrù, Sivia; Lay, Giancarlo

    2012-09-01

    To test tangential and not-tangential hybrid intensity modulated radiation therapy (IMRT) for whole-breast irradiation. Seventy-eight (36 right-, 42 left-) breast patients were randomly selected. Hybrid IMRT was performed by direct aperture optimization. A semiautomated method for planning hybrid IMRT was implemented using Pinnacle scripts. A plan optimization volume (POV), defined as the portion of the planning target volume covered by the open beams, was used as the target objective during inverse planning. Treatment goals were to prescribe a minimum dose of 47.5 Gy to greater than 90% of the POV and to minimize the POV and/or normal tissue receiving a dose greater than 107%. When treatment goals were not achieved by using a 4-field technique (2 conventional open plus 2 IMRT tangents), a 6-field technique was applied, adding 2 non tangential (anterior-oblique) IMRT beams. Using scripts, manual procedures were minimized (choice of optimal beam angle, setting monitor units for open tangentials, and POV definition). Treatment goals were achieved by using the 4-field technique in 61 of 78 (78%) patients. The 6-field technique was applied in the remaining 17 of 78 (22%) patients, allowing for significantly better achievement of goals, at the expense of an increase of low-dose (∼5 Gy) distribution in the contralateral tissue, heart, and lungs but with no significant increase of higher doses (∼20 Gy) in heart and lungs. The mean monitor unit contribution to IMRT beams was significantly greater (18.7% vs 9.9%) in the group of patients who required 6-field procedure. Because hybrid IMRT can be performed semiautomatically, it can be planned for a large number of patients with little impact on human or departmental resources, promoting it as the standard practice for whole-breast irradiation. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Planning Hybrid Intensity Modulated Radiation Therapy for Whole-breast Irradiation

    International Nuclear Information System (INIS)

    Farace, Paolo; Zucca, Sergio; Solla, Ignazio; Fadda, Giuseppina; Durzu, Silvia; Porru, Sergio; Meleddu, Gianfranco; Deidda, Maria Assunta; Possanzini, Marco; Orrù, Sivia; Lay, Giancarlo

    2012-01-01

    Purpose: To test tangential and not-tangential hybrid intensity modulated radiation therapy (IMRT) for whole-breast irradiation. Methods and Materials: Seventy-eight (36 right-, 42 left-) breast patients were randomly selected. Hybrid IMRT was performed by direct aperture optimization. A semiautomated method for planning hybrid IMRT was implemented using Pinnacle scripts. A plan optimization volume (POV), defined as the portion of the planning target volume covered by the open beams, was used as the target objective during inverse planning. Treatment goals were to prescribe a minimum dose of 47.5 Gy to greater than 90% of the POV and to minimize the POV and/or normal tissue receiving a dose greater than 107%. When treatment goals were not achieved by using a 4-field technique (2 conventional open plus 2 IMRT tangents), a 6-field technique was applied, adding 2 non tangential (anterior-oblique) IMRT beams. Results: Using scripts, manual procedures were minimized (choice of optimal beam angle, setting monitor units for open tangentials, and POV definition). Treatment goals were achieved by using the 4-field technique in 61 of 78 (78%) patients. The 6-field technique was applied in the remaining 17 of 78 (22%) patients, allowing for significantly better achievement of goals, at the expense of an increase of low-dose (∼5 Gy) distribution in the contralateral tissue, heart, and lungs but with no significant increase of higher doses (∼20 Gy) in heart and lungs. The mean monitor unit contribution to IMRT beams was significantly greater (18.7% vs 9.9%) in the group of patients who required 6-field procedure. Conclusions: Because hybrid IMRT can be performed semiautomatically, it can be planned for a large number of patients with little impact on human or departmental resources, promoting it as the standard practice for whole-breast irradiation.

  13. Ototoxicity After Intensity-Modulated Radiation Therapy and Cisplatin-Based Chemotherapy in Children With Medulloblastoma

    International Nuclear Information System (INIS)

    Paulino, Arnold C.; Lobo, Mark; Teh, Bin S.; Okcu, M. Fatih; South, Michael; Butler, E. Brian; Su, Jack; Chintagumpala, Murali

    2010-01-01

    Purpose: To report the incidence of Pediatric Oncology Group (POG) Grade 3 or 4 ototoxicity in a cohort of patients treated with craniospinal irradiation (CSI) followed by posterior fossa (PF) and/or tumor bed (TB) boost using intensity-modulated radiation therapy (IMRT). Methods and Materials: From 1998 to 2006, 44 patients with medulloblastoma were treated with CSI followed by IMRT to the PF and/or TB and cisplatin-based chemotherapy. Patients with standard-risk disease were treated with 18 to 23.4 Gy CSI followed by either a (1) PF boost to 36 Gy and TB boost to 54 to 55.8 Gy or (2) TB boost to 55.8 Gy. Patients with high-risk disease received 36 to 39.6 Gy CSI followed by a (1) PF boost to 54 to 55.8 Gy, (2) PF boost to 45 Gy and TB boost to 55.8 Gy, or (3) TB boost to 55.8 Gy. Median audiogram follow-up was 41 months (range, 11-92.4 months). Results: POG Grade Ototoxicity 0, 1, 2, 3. and 4 was found in 29, 32, 11, 13. and 3 ears. respectively, with POG Grade 3 or 4 accounting for 18.2% of cases. There was a statistically significant difference in mean radiation dose (D mean ) cochlea according to degree of ototoxicity, with D mean cochlea increasing with severity of hearing loss (p = 0.027). Conclusions: Severe ototoxicity was seen in 18.2% of ears in children treated with IMRT boost and cisplatin-based chemotherapy. Increasing dose to the cochlea was associated with increasing severity of hearing loss.

  14. Patterns of Disease Recurrence Following Treatment of Oropharyngeal Cancer With Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Garden, Adam S., E-mail: agarden@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Dong, Lei [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Morrison, William H. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Stugis, Erich M. [Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Glisson, Bonnie S. [Department of Thoracic/Head and Neck Medicine, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Frank, Steven J.; Beadle, Beth M.; Gunn, Gary B. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Schwartz, David L. [Department of Radiation Medicine, Long Island Jewish Medical Center, New Hyde Park, NY (United States); Kies, Merill S. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Department of Thoracic/Head and Neck Medicine, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Weber, Randal S. [Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Ang, K. Kian; Rosenthal, David I. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2013-03-15

    Purpose: To report mature results of a large cohort of patients diagnosed with squamous cell carcinoma of the oropharynx who were treated with intensity modulated radiation therapy (IMRT). Methods and Materials: The database of patients irradiated at The University of Texas, M.D. Anderson Cancer Center was searched for patients diagnosed with oropharyngeal cancer and treated with IMRT between 2000 and 2007. A retrospective review of outcome data was performed. Results: The cohort consisted of 776 patients. One hundred fifty-nine patients (21%) were current smokers, 279 (36%) former smokers, and 337 (43%) never smokers. T and N categories and American Joint Committee on Cancer group stages were distributed as follows: T1/x, 288 (37%); T2, 288 (37%); T3, 113 (15%); T4, 87 (11%); N0, 88(12%); N1/x, 140 (18%); N2a, 101 (13%); N2b, 269 (35%); N2c, 122 (16%); and N3, 56 (7%); stage I, 18(2%); stage II, 40(5%); stage III, 150(19%); and stage IV, 568(74%). Seventy-one patients (10%) presented with nodes in level IV. Median follow-up was 54 months. The 5-year overall survival, locoregional control, and overall recurrence-free survival rates were 84%, 90%, and 82%, respectively. Primary site recurrence developed in 7% of patients, and neck recurrence with primary site control in 3%. We could only identify 12 patients (2%) who had locoregional recurrence outside the high-dose target volumes. Poorer survival rates were observed in current smokers, patients with larger primary (T) tumors and lower neck disease. Conclusions: Patients with oropharyngeal cancer treated with IMRT have excellent disease control. Locoregional recurrence was uncommon, and most often occurred in the high dose volumes. Parotid sparing was accomplished in nearly all patients without compromising tumor coverage.

  15. Reoptimization of Intensity Modulated Proton Therapy Plans Based on Linear Energy Transfer

    Energy Technology Data Exchange (ETDEWEB)

    Unkelbach, Jan, E-mail: junkelbach@mgh.harvard.edu [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Botas, Pablo [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Faculty of Physics, Ruprecht-Karls-Universität Heidelberg, Heidelberg (Germany); Giantsoudi, Drosoula; Gorissen, Bram L.; Paganetti, Harald [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2016-12-01

    Purpose: We describe a treatment plan optimization method for intensity modulated proton therapy (IMPT) that avoids high values of linear energy transfer (LET) in critical structures located within or near the target volume while limiting degradation of the best possible physical dose distribution. Methods and Materials: To allow fast optimization based on dose and LET, a GPU-based Monte Carlo code was extended to provide dose-averaged LET in addition to dose for all pencil beams. After optimizing an initial IMPT plan based on physical dose, a prioritized optimization scheme is used to modify the LET distribution while constraining the physical dose objectives to values close to the initial plan. The LET optimization step is performed based on objective functions evaluated for the product of LET and physical dose (LET×D). To first approximation, LET×D represents a measure of the additional biological dose that is caused by high LET. Results: The method is effective for treatments where serial critical structures with maximum dose constraints are located within or near the target. We report on 5 patients with intracranial tumors (high-grade meningiomas, base-of-skull chordomas, ependymomas) in whom the target volume overlaps with the brainstem and optic structures. In all cases, high LET×D in critical structures could be avoided while minimally compromising physical dose planning objectives. Conclusion: LET-based reoptimization of IMPT plans represents a pragmatic approach to bridge the gap between purely physical dose-based and relative biological effectiveness (RBE)-based planning. The method makes IMPT treatments safer by mitigating a potentially increased risk of side effects resulting from elevated RBE of proton beams near the end of range.

  16. Individualized Selection of Beam Angles and Treatment Isocenter in Tangential Breast Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Penninkhof, Joan, E-mail: j.penninkhof@erasmusmc.nl [Department of Radiation Oncology, Erasmus M.C. Cancer Institute, Rotterdam (Netherlands); Spadola, Sara [Department of Radiation Oncology, Erasmus M.C. Cancer Institute, Rotterdam (Netherlands); Department of Physics and Astronomy, Alma Mater Studiorum, University of Bologna, Bologna (Italy); Breedveld, Sebastiaan; Baaijens, Margreet [Department of Radiation Oncology, Erasmus M.C. Cancer Institute, Rotterdam (Netherlands); Lanconelli, Nico [Department of Physics and Astronomy, Alma Mater Studiorum, University of Bologna, Bologna (Italy); Heijmen, Ben [Department of Radiation Oncology, Erasmus M.C. Cancer Institute, Rotterdam (Netherlands)

    2017-06-01

    Purpose and Objective: Propose a novel method for individualized selection of beam angles and treatment isocenter in tangential breast intensity modulated radiation therapy (IMRT). Methods and Materials: For each patient, beam and isocenter selection starts with the fully automatic generation of a large database of IMRT plans (up to 847 in this study); each of these plans belongs to a unique combination of isocenter position, lateral beam angle, and medial beam angle. The imposed hard planning constraint on patient maximum dose may result in plans with unacceptable target dose delivery. Such plans are excluded from further analyses. Owing to differences in beam setup, database plans differ in mean doses to organs at risk (OARs). These mean doses are used to construct 2-dimensional graphs, showing relationships between: (1) contralateral breast dose and ipsilateral lung dose; and (2) contralateral breast dose and heart dose (analyzed only for left-sided). The graphs can be used for selection of the isocenter and beam angles with the optimal, patient-specific tradeoffs between the mean OAR doses. For 30 previously treated patients (15 left-sided and 15 right-sided tumors), graphs were generated considering only the clinically applied isocenter with 121 tangential beam angle pairs. For 20 of the 30 patients, 6 alternative isocenters were also investigated. Results: Computation time for automatic generation of 121 IMRT plans took on average 30 minutes. The generated graphs demonstrated large variations in tradeoffs between conflicting OAR objectives, depending on beam angles and patient anatomy. For patients with isocenter optimization, 847 IMRT plans were considered. Adding isocenter position optimization next to beam angle optimization had a small impact on the final plan quality. Conclusion: A method is proposed for individualized selection of beam angles in tangential breast IMRT. This may be especially important for patients with cardiac risk factors or an

  17. Three-Year Outcomes of Breast Intensity-Modulated Radiation Therapy With Simultaneous Integrated Boost

    International Nuclear Information System (INIS)

    McDonald, Mark W.; Godette, Karen D.; Whitaker, Daisy J.; Davis, Lawrence W.; Johnstone, Peter A.S.

    2010-01-01

    Purpose: To report our clinical experience using breast intensity-modulated radiation therapy with simultaneous integrated boost (SIB-IMRT). Methods and Materials: Retrospective review identified 354 Stage 0 to III breast cancer patients treated with SIB-IMRT after conservative surgery between 2003 and 2006. The most common fractionation (89%) simultaneously delivered 1.8 Gy to the ipsilateral breast tissue and 2.14 Gy to the resection cavity, yielding a breast dose of 45 Gy (25 fractions) and cavity dose 59.92 Gy (28 fractions), biologically equivalent for tumor control to 45 Gy to the breast with sequential 16-Gy boost (33 fractions). Results: A total of 356 breasts in 354 patients were treated: 282 with invasive breast cancer, and 74 with ductal carcinoma in situ (DCIS). For left breast radiation, median cardiac V 15 was 2.9% and left ventricular V 15 1.7%. Median follow-up was 33 months (range, 4-73 months). Acute toxicity was Grade 1 in 57% of cases, Grade 2 in 43%, and Grade 3 in <1%. For invasive breast cancer, the 3-year overall survival was 97.6% and risk of any locoregional recurrence was 2.8%. For ductal carcinoma in situ, 3-year overall survival was 98% and risk of locoregional recurrence 1.4%. In 142 cases at a minimum of 3 years follow-up, global breast cosmesis was judged by physicians as good or excellent in 96.5% and fair in 3.5%. Conclusions: Breast SIB-IMRT reduced treatment duration by five fractions with a favorable acute toxicity profile and low cardiac dose for left breast treatment. At 3 years, locoregional control was excellent, and initial assessment suggested good or excellent cosmesis in a high percentage of evaluable patients.

  18. Intensity-modulated radiation therapy for T4 nasopharyngeal carcinoma. Treatment results and locoregional

    International Nuclear Information System (INIS)

    Chen, J.L.Y.; Tsai, C.L.; Chen, W.Y.; Wang, C.W.; Huang, Y.S.; Chen, Y.F.; Kuo, S.H.; National Taiwan Univ. College of Medicine, Taipei; Hong, R.L.; Ko, J.Y.; Lou, P.J.

    2013-01-01

    Purpose: The purpose of this work was to examine outcomes in patients with T4 nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). Methods and materials: Between 2007 and 2010, 154 patients with nonmetastatic T4 NPC were treated with IMRT to a total dose of 70 Gy in 33-35 fractions. In addition, 97 % of patients received concurrent platinum-based chemotherapy. The median follow-up time was 52.8 months. Results: The rates of 5-year actuarial locoregional control, distant metastasis-free survival, progression free-survival, and overall survival (OS) were 81.2, 72.2, 61.9, and 78.1 %, respectively. A total of 27 patients had locoregional recurrence: 85.2 % in-field failures, 11.1 % marginal failures, and 3.7 % out-of-field failures. Fourteen patients with locoregional recurrence received aggressive treatments, including nasopharyngectomy, neck dissection, or re-irradiation, and the 5-year OS rate tended to be better (61.9 %) compared to those receiving conservative treatment (32.0 %, p = 0.051). In patients treated with 1 course of radiotherapy, grade ≥ 3 toxicities of ototoxicity, neck fibrosis, xerostomia, epistaxis, and radiographic temporal lobe necrosis occurred in 18.2, 9.8, 6.3, 2.1, and 5.6 % of patients, respectively. Increased ototoxicity, osteonecrosis, severe nasal bleeding, and temporal necrosis were observed in patients treated by re-irradiation. Conclusion: IMRT offers good locoregional control in patients with T4 NPC. For patients with locoregional recurrence after definitive radiotherapy, aggressive local treatment may be considered for a better outcome. (orig.)

  19. Characterization of a commercial multileaf collimator used for intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Low, Daniel A.; Sohn, Jason W.; Klein, Eric E.; Markman, Jerry; Mutic, Sasa; Dempsey, James F.

    2001-01-01

    The characteristics of a commercial multileaf collimator (MLC) to deliver static and dynamic multileaf collimation (SMLC and DMLC, respectively) were investigated to determine their influence on intensity modulated radiation therapy (IMRT) treatment planning and quality assurance. The influence of MLC leaf positioning accuracy on sequentially abutted SMLC fields was measured by creating abutting fields with selected gaps and overlaps. These data were also used to measure static leaf positioning precision. The characteristics of high leaf-velocity DMLC delivery were measured with constant velocity leaf sequences starting with an open field and closing a single leaf bank. A range of 1-72 monitor units (MU) was used providing a range of leaf velocities. The field abutment measurements yielded dose errors (as a percentage of the open field max dose) of 16.7±0.7% mm-1 and 12.8±0.7% mm-1 for 6 MV and 18 MV photon beams, respectively. The MLC leaf positioning precision was 0.080±0.018 mm (single standard deviation) highlighting the excellent delivery hardware tolerances for the tested beam delivery geometry. The high leaf-velocity DMLC measurements showed delivery artifacts when the leaf sequence and selected monitor units caused the linear accelerator to move the leaves at their maximum velocity while modulating the accelerator dose rate to deliver the desired leaf and MU sequence (termed leaf-velocity limited delivery). According to the vendor, a unique feature to their linear accelerator and MLC is that the dose rate is reduced to provide the correct cm MU-1 leaf velocity when the delivery is leaf-velocity limited. However, it was found that the system delivered roughly 1 MU per pulse when the delivery was leaf-velocity limited causing dose profiles to exhibit discrete steps rather than a smooth dose gradient. The root mean square difference between the steps and desired linear gradient was less than 3% when more than 4 MU were used. The average dose per MU was

  20. Tumor trailing strategy for intensity-modulated radiation therapy of moving targets

    International Nuclear Information System (INIS)

    Trofimov, Alexei; Vrancic, Christian; Chan, Timothy C. Y.; Sharp, Gregory C.; Bortfeld, Thomas

    2008-01-01

    Internal organ motion during the course of radiation therapy of cancer affects the distribution of the delivered dose and, generally, reduces its conformality to the targeted volume. Previously proposed approaches aimed at mitigating the effect of internal motion in intensity-modulated radiation therapy (IMRT) included expansion of the target margins, motion-correlated delivery (e.g., respiratory gating, tumor tracking), and adaptive treatment plan optimization employing a probabilistic description of motion. We describe and test the tumor trailing strategy, which utilizes the synergy of motion-adaptive treatment planning and delivery methods. We regard the (rigid) target motion as a superposition of a relatively fast cyclic component (e.g., respiratory) and slow aperiodic trends (e.g., the drift of exhalation baseline). In the trailing approach, these two components of motion are decoupled and dealt with separately. Real-time motion monitoring is employed to identify the 'slow' shifts, which are then corrected by applying setup adjustments. The delivery does not track the target position exactly, but trails the systematic trend due to the delay between the time a shift occurs, is reliably detected, and, subsequently, corrected. The ''fast'' cyclic motion is accounted for with a robust motion-adaptive treatment planning, which allows for variability in motion parameters (e.g., mean and extrema of the tidal volume, variable period of respiration, and expiratory duration). Motion-surrogate data from gated IMRT treatments were used to provide probability distribution data for motion-adaptive planning and to test algorithms that identified systematic trends in the character of motion. Sample IMRT fields were delivered on a clinical linear accelerator to a programmable moving phantom. Dose measurements were performed with a commercial two-dimensional ion-chamber array. The results indicate that by reducing intrafractional motion variability, the trailing strategy

  1. Improving intensity-modulated radiation therapy using the anatomic beam orientation optimization algorithm

    International Nuclear Information System (INIS)

    Potrebko, Peter S.; McCurdy, Boyd M. C.; Butler, James B.; El-Gubtan, Adel S.

    2008-01-01

    A novel, anatomic beam orientation optimization (A-BOO) algorithm is proposed to significantly improve conventional intensity-modulated radiation therapy (IMRT). The A-BOO algorithm vectorially analyses polygonal surface mesh data of contoured patient anatomy. Five optimal (5-opt) deliverable beam orientations are selected based on (1) tangential orientation bisecting the target and adjacent organ's-at-risk (OARs) to produce precipitous dose gradients between them and (2) parallel incidence with polygon features of the target volume to facilitate conformal coverage. The 5-opt plans were compared to standard five, seven, and nine equiangular-spaced beam plans (5-equi, 7-equi, 9-equi) for: (1) gastric, (2) Radiation Therapy Oncology Group (RTOG) P-0126 prostate, and (3) RTOG H-0022 oropharyngeal (stage-III, IV) cancer patients. In the gastric case, the noncoplanar 5-opt plan reduced the right kidney V 20 Gy by 32.2%, 23.2%, and 20.6% compared to plans with five, seven, and nine equiangular-spaced beams. In the prostate case, the coplanar 5-opt plan produced similar rectal sparing as the 7-equi and 9-equi plans with a reduction of the V 75, V 70, V 65, and V 60 Gy of 2.4%, 5.3%, 7.0%, and 9.5% compared to the 5-equi plan. In the stage-III and IV oropharyngeal cases, the noncoplanar 5-opt plan substantially reduced the V 30 Gy and mean dose to the contralateral parotid compared to plans with five, seven, and nine equiangular-spaced beams: (stage-III) 7.1%, 5.2%, 6.8%, and 5.1, 3.5, 3.7 Gy and (stage-IV) 10.2%, 10.2%, 9.8% and 7.0, 7.1, 7.2 Gy. The geometry-based A-BOO algorithm has been demonstrated to be robust for application to a variety of IMRT treatment sites. Beam orientations producing significant improvements in OAR sparing over conventional IMRT can be automatically produced in minutes compared to hours with existing dose-based beam orientation optimization methods

  2. Dosimetric effect of beam arrangement for intensity-modulated radiation therapy in the treatment of upper thoracic esophageal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yuchuan [Division of Radiation Physics, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu (China); Deng, Min; Zhou, Xiaojuan [Department of Thoracic Oncology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu (China); Lin, Qiang; Du, Bin [Division of Radiation Physics, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu (China); Tian, Xue; Xu, Yong; Wang, Jin; Lu, You [Department of Thoracic Oncology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu (China); Gong, Youling, E-mail: gongyouling@hotmail.com [Department of Thoracic Oncology, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu (China)

    2017-04-01

    To evaluate the lung sparing in intensity-modulated radiation therapy (IMRT) for patients with upper thoracic esophageal tumors extending inferiorly to the thorax by different beam arrangement. Overall, 15 patient cases with cancer of upper thoracic esophagus were selected for a retrospective treatment-planning study. Intensity-modulated radiation therapy plans using 4, 5, and 7 beams (4B, 5B, and 7B) were developed for each patient by direct machine parameter optimization (DMPO). All plans were evaluated with respect to dose volumes to irradiated targets and normal structures, with statistical comparisons made between 4B with 5B and 7B intensity-modulated radiation therapy plans. Differences among plans were evaluated using a two-tailed Friedman test at a statistical significance of p < 0.05. The maximum dose, average dose, and the conformity index (CI) of planning target volume 1 (PTV1) were similar for 3 plans for each case. No significant difference of coverage for planning target volume 1 and maximum dose for spinal cords were observed among 3 plans in present study (p > 0.05). The average V{sub 5}, V{sub 13}, V{sub 20}, mean lung dose, and generalized equivalent uniform dose (gEUD) for the total lung were significantly lower in 4B-plans than those data in 5B-plans and 7B-plans (p < 0.01). Although the average V{sub 30} for the total lung were significantly higher in 4B-plans than those in 5B-plans and 7B-plans (p < 0.05). In addition, when comparing with the 4B-plans, the conformity/heterogeneity index of the 5B- and 7B-plans were significantly superior (p < 0.05). The 4B-intensity-modulated radiation therapy plan has advantage to address the specialized problem of lung sparing to low- and intermediate-dose exposure in the thorax when dealing with relative long tumors extended inferiorly to the thoracic esophagus for upper esophageal carcinoma with the cost for less conformity. Studies are needed to compare the superiority of volumetric modulated arc therapy

  3. Dosimetric effect of beam arrangement for intensity-modulated radiation therapy in the treatment of upper thoracic esophageal carcinoma

    International Nuclear Information System (INIS)

    Fu, Yuchuan; Deng, Min; Zhou, Xiaojuan; Lin, Qiang; Du, Bin; Tian, Xue; Xu, Yong; Wang, Jin; Lu, You; Gong, Youling

    2017-01-01

    To evaluate the lung sparing in intensity-modulated radiation therapy (IMRT) for patients with upper thoracic esophageal tumors extending inferiorly to the thorax by different beam arrangement. Overall, 15 patient cases with cancer of upper thoracic esophagus were selected for a retrospective treatment-planning study. Intensity-modulated radiation therapy plans using 4, 5, and 7 beams (4B, 5B, and 7B) were developed for each patient by direct machine parameter optimization (DMPO). All plans were evaluated with respect to dose volumes to irradiated targets and normal structures, with statistical comparisons made between 4B with 5B and 7B intensity-modulated radiation therapy plans. Differences among plans were evaluated using a two-tailed Friedman test at a statistical significance of p < 0.05. The maximum dose, average dose, and the conformity index (CI) of planning target volume 1 (PTV1) were similar for 3 plans for each case. No significant difference of coverage for planning target volume 1 and maximum dose for spinal cords were observed among 3 plans in present study (p > 0.05). The average V 5 , V 13 , V 20 , mean lung dose, and generalized equivalent uniform dose (gEUD) for the total lung were significantly lower in 4B-plans than those data in 5B-plans and 7B-plans (p < 0.01). Although the average V 30 for the total lung were significantly higher in 4B-plans than those in 5B-plans and 7B-plans (p < 0.05). In addition, when comparing with the 4B-plans, the conformity/heterogeneity index of the 5B- and 7B-plans were significantly superior (p < 0.05). The 4B-intensity-modulated radiation therapy plan has advantage to address the specialized problem of lung sparing to low- and intermediate-dose exposure in the thorax when dealing with relative long tumors extended inferiorly to the thoracic esophagus for upper esophageal carcinoma with the cost for less conformity. Studies are needed to compare the superiority of volumetric modulated arc therapy with intensity-modulated

  4. Comparison of testicular dose delivered by intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) in patients with prostate cancer

    International Nuclear Information System (INIS)

    Martin, Jeffrey M.; Handorf, Elizabeth A.; Price, Robert A.; Cherian, George; Buyyounouski, Mark K.; Chen, David Y.; Kutikov, Alexander; Johnson, Matthew E.; Ma, Chung-Ming Charlie; Horwitz, Eric M.

    2015-01-01

    A small decrease in testosterone level has been documented after prostate irradiation, possibly owing to the incidental dose to the testes. Testicular doses from prostate external beam radiation plans with either intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT) were calculated to investigate any difference. Testicles were contoured for 16 patients being treated for localized prostate cancer. For each patient, 2 plans were created: 1 with IMRT and 1 with VMAT. No specific attempt was made to reduce testicular dose. Minimum, maximum, and mean doses to the testicles were recorded for each plan. Of the 16 patients, 4 received a total dose of 7800 cGy to the prostate alone, 7 received 8000 cGy to the prostate alone, and 5 received 8000 cGy to the prostate and pelvic lymph nodes. The mean (range) of testicular dose with an IMRT plan was 54.7 cGy (21.1 to 91.9) and 59.0 cGy (25.1 to 93.4) with a VMAT plan. In 12 cases, the mean VMAT dose was higher than the mean IMRT dose, with a mean difference of 4.3 cGy (p = 0.019). There was a small but statistically significant increase in mean testicular dose delivered by VMAT compared with IMRT. Despite this, it unlikely that there is a clinically meaningful difference in testicular doses from either modality

  5. Comparison of testicular dose delivered by intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) in patients with prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Jeffrey M. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Handorf, Elizabeth A. [Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, PA (United States); Price, Robert A.; Cherian, George [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Buyyounouski, Mark K. [Department of Radiation Oncology, Stanford University, Stanford, CA (United States); Chen, David Y.; Kutikov, Alexander [Department of Urologic Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Johnson, Matthew E.; Ma, Chung-Ming Charlie [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States); Horwitz, Eric M., E-mail: eric.horwitz@fccc.edu [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States)

    2015-10-01

    A small decrease in testosterone level has been documented after prostate irradiation, possibly owing to the incidental dose to the testes. Testicular doses from prostate external beam radiation plans with either intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT) were calculated to investigate any difference. Testicles were contoured for 16 patients being treated for localized prostate cancer. For each patient, 2 plans were created: 1 with IMRT and 1 with VMAT. No specific attempt was made to reduce testicular dose. Minimum, maximum, and mean doses to the testicles were recorded for each plan. Of the 16 patients, 4 received a total dose of 7800 cGy to the prostate alone, 7 received 8000 cGy to the prostate alone, and 5 received 8000 cGy to the prostate and pelvic lymph nodes. The mean (range) of testicular dose with an IMRT plan was 54.7 cGy (21.1 to 91.9) and 59.0 cGy (25.1 to 93.4) with a VMAT plan. In 12 cases, the mean VMAT dose was higher than the mean IMRT dose, with a mean difference of 4.3 cGy (p = 0.019). There was a small but statistically significant increase in mean testicular dose delivered by VMAT compared with IMRT. Despite this, it unlikely that there is a clinically meaningful difference in testicular doses from either modality.

  6. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a 60Co Magnetic Resonance Image Guidance Radiation Therapy System

    International Nuclear Information System (INIS)

    Wooten, H. Omar; Green, Olga; Yang, Min; DeWees, Todd; Kashani, Rojano; Olsen, Jeff; Michalski, Jeff; Yang, Deshan; Tanderup, Kari; Hu, Yanle; Li, H. Harold; Mutic, Sasa

    2015-01-01

    Purpose: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating 60 Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. Methods and Materials: The ViewRay treatment planning system (Oakwood Village, OH) was used to create 60 Co IMRT treatment plans for 33 cancer patients with disease in the abdominal, pelvic, thorax, and head and neck regions using physician-specified patient-specific target coverage and organ at risk (OAR) objectives. Backup plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The 60 Co and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses and heterogeneity indices (HI) for planning target volumes (PTVs) and maximum, mean, and dose-volume histogram (DVH) values for OARs. Results: All 60 Co IMRT plans achieved PTV coverage and OAR sparing that were similar to linac plans. PTV conformity for 60 Co was within <1% and 3% of linac plans for 100% and 95% prescription reference isodoses, respectively, and heterogeneity was on average 4% greater. Comparisons of OAR mean dose showed generally better sparing with linac plans in the low-dose range <20 Gy, but comparable sparing for organs with mean doses >20 Gy. The mean doses for all 60 Co plan OARs were within clinical tolerances. Conclusions: A commercial 60 Co MR-IGRT device can produce highly conformal IMRT treatment plans similar in quality to linac IMRT for a variety of disease sites. Additional work is in progress to evaluate the clinical benefit of other novel features of this MR-IGRT system

  7. Cost-Effectiveness Analysis of Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy for Anal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hodges, Joseph C., E-mail: joseph.hodges@utsouthwestern.edu [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Beg, Muhammad S. [Division of Hematology and Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Das, Prajnan [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Meyer, Jeffrey [Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States)

    2014-07-15

    Purpose: To compare the cost-effectiveness of intensity modulated radiation therapy (IMRT) and 3-dimensional conformal radiation therapy (3D-CRT) for anal cancer and determine disease, patient, and treatment parameters that influence the result. Methods and Materials: A Markov decision model was designed with the various disease states for the base case of a 65-year-old patient with anal cancer treated with either IMRT or 3D-CRT and concurrent chemotherapy. Health states accounting for rates of local failure, colostomy failure, treatment breaks, patient prognosis, acute and late toxicities, and the utility of toxicities were informed by existing literature and analyzed with deterministic and probabilistic sensitivity analysis. Results: In the base case, mean costs and quality-adjusted life expectancy in years (QALY) for IMRT and 3D-CRT were $32,291 (4.81) and $28,444 (4.78), respectively, resulting in an incremental cost-effectiveness ratio of $128,233/QALY for IMRT compared with 3D-CRT. Probabilistic sensitivity analysis found that IMRT was cost-effective in 22%, 47%, and 65% of iterations at willingness-to-pay thresholds of $50,000, $100,000, and $150,000 per QALY, respectively. Conclusions: In our base model, IMRT was a cost-ineffective strategy despite the reduced acute treatment toxicities and their associated costs of management. The model outcome was sensitive to variations in local and colostomy failure rates, as well as patient-reported utilities relating to acute toxicities.

  8. Cost-Effectiveness Analysis of Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy for Anal Cancer

    International Nuclear Information System (INIS)

    Hodges, Joseph C.; Beg, Muhammad S.; Das, Prajnan; Meyer, Jeffrey

    2014-01-01

    Purpose: To compare the cost-effectiveness of intensity modulated radiation therapy (IMRT) and 3-dimensional conformal radiation therapy (3D-CRT) for anal cancer and determine disease, patient, and treatment parameters that influence the result. Methods and Materials: A Markov decision model was designed with the various disease states for the base case of a 65-year-old patient with anal cancer treated with either IMRT or 3D-CRT and concurrent chemotherapy. Health states accounting for rates of local failure, colostomy failure, treatment breaks, patient prognosis, acute and late toxicities, and the utility of toxicities were informed by existing literature and analyzed with deterministic and probabilistic sensitivity analysis. Results: In the base case, mean costs and quality-adjusted life expectancy in years (QALY) for IMRT and 3D-CRT were $32,291 (4.81) and $28,444 (4.78), respectively, resulting in an incremental cost-effectiveness ratio of $128,233/QALY for IMRT compared with 3D-CRT. Probabilistic sensitivity analysis found that IMRT was cost-effective in 22%, 47%, and 65% of iterations at willingness-to-pay thresholds of $50,000, $100,000, and $150,000 per QALY, respectively. Conclusions: In our base model, IMRT was a cost-ineffective strategy despite the reduced acute treatment toxicities and their associated costs of management. The model outcome was sensitive to variations in local and colostomy failure rates, as well as patient-reported utilities relating to acute toxicities

  9. High-accuracy dosimetry study for intensity-modulated radiation therapy(IMRT) commissioning

    International Nuclear Information System (INIS)

    Jeong, Hae Sun

    2010-02-01

    Intensity-modulated radiation therapy (IMRT), an advanced modality of high-precision radiotherapy, allows for an increase in dose to the tumor volume without increasing the dose to nearby critical organs. In order to successfully achieve the treatment, intensive dosimetry with accurate dose verification is necessary. A dosimetry for IMRT, however, is a challenging task due to dosimetric ally unfavorable phenomena such as dramatic changes of the dose at the field boundaries, dis-equilibrium of the electrons, non-uniformity between the detector and the phantom materials, and distortion of scanner-read doses. In the present study, therefore, the LEGO-type multi-purpose dosimetry phantom was developed and used for the studies on dose measurements and correction. Phantom materials for muscle, fat, bone, and lung tissue were selected after considering mass density, atomic composition, effective atomic number, and photon interaction coefficients. The phantom also includes dosimeter holders for several different types of detectors including films, which accommodates a construction of different designs of phantoms as necessary. In order to evaluate its performance, the developed phantom was tested by measuring the point dose and the percent depth dose (PDD) for small size fields under several heterogeneous conditions. However, the measurements with the two types of dosimeter did not agree well for the field sizes less than 1 x 1 cm 2 in muscle and bone, and less than 3 x 3 cm 2 in air cavity. Thus, it was recognized that several studies on small fields dosimetry and correction methods for the calculation with a PMCEPT code are needed. The under-estimated values from the ion chamber were corrected with a convolution method employed to eliminate the volume effect of the chamber. As a result, the discrepancies between the EBT film and the ion chamber measurements were significantly decreased, from 14% to 1% (1 x 1 cm 2 ), 10% to 1% (0.7 x 0.7 cm 2 ), and 42% to 7% (0.5 x 0

  10. High-accuracy dosimetry study for intensity-modulated radiation therapy(IMRT) commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hae Sun

    2010-02-15

    Intensity-modulated radiation therapy (IMRT), an advanced modality of high-precision radiotherapy, allows for an increase in dose to the tumor volume without increasing the dose to nearby critical organs. In order to successfully achieve the treatment, intensive dosimetry with accurate dose verification is necessary. A dosimetry for IMRT, however, is a challenging task due to dosimetric ally unfavorable phenomena such as dramatic changes of the dose at the field boundaries, dis-equilibrium of the electrons, non-uniformity between the detector and the phantom materials, and distortion of scanner-read doses. In the present study, therefore, the LEGO-type multi-purpose dosimetry phantom was developed and used for the studies on dose measurements and correction. Phantom materials for muscle, fat, bone, and lung tissue were selected after considering mass density, atomic composition, effective atomic number, and photon interaction coefficients. The phantom also includes dosimeter holders for several different types of detectors including films, which accommodates a construction of different designs of phantoms as necessary. In order to evaluate its performance, the developed phantom was tested by measuring the point dose and the percent depth dose (PDD) for small size fields under several heterogeneous conditions. However, the measurements with the two types of dosimeter did not agree well for the field sizes less than 1 x 1 cm{sup 2} in muscle and bone, and less than 3 x 3 cm{sup 2} in air cavity. Thus, it was recognized that several studies on small fields dosimetry and correction methods for the calculation with a PMCEPT code are needed. The under-estimated values from the ion chamber were corrected with a convolution method employed to eliminate the volume effect of the chamber. As a result, the discrepancies between the EBT film and the ion chamber measurements were significantly decreased, from 14% to 1% (1 x 1 cm{sup 2}), 10% to 1% (0.7 x 0.7 cm{sup 2}), and 42

  11. Acute Toxicity After Image-Guided Intensity Modulated Radiation Therapy Compared to 3D Conformal Radiation Therapy in Prostate Cancer Patients

    NARCIS (Netherlands)

    Wortel, Ruud C.; Incrocci, Luca; Pos, Floris J.; Lebesque, Joos V.; Witte, Marnix G.; van der Heide, Uulke A.; van Herk, Marcel; Heemsbergen, Wilma D.

    2015-01-01

    Purpose: Image-guided intensity modulated radiation therapy (IG-IMRT) allows significant dose reductions to organs at risk in prostate cancer patients. However, clinical data identifying the benefits of IG-IMRT in daily practice are scarce. The purpose of this study was to compare dose distributions

  12. State of the art on dose prescription, reporting and recording in Intensity-Modulated Radiation Therapy (ICRU report No. 83)

    International Nuclear Information System (INIS)

    Gregoire, V.; Mackie, T.R.

    2011-01-01

    The International Commission on Radiation Units and Measurements (ICRU) report No. 83 provides the information necessary to standardize techniques and procedures and to harmonize the prescribing, recording, and reporting of intensity modulated radiation therapy. Applicable concepts and recommendations in previous ICRU reports concerning radiation therapy were adopted, and new concepts were elaborated. In particular, additional recommendations were given on the selection and delineation of the targets volumes and the organs at risk; concepts of dose prescription and dose-volume reporting have also been refined. (authors)

  13. Examination of geometric and dosimetric accuracies of gated step-and-shoot intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Wiersma, R. D.; Xing, L.

    2007-01-01

    Due to the complicated technical nature of gated radiation therapy, electronic and mechanical limitations may affect the precision of delivery. The purpose of this study is to investigate the geometric and dosimetric accuracies of gated step-and-shoot intensity modulated radiation treatments (SS-IMRT). Unique segmental MLC plans are designed, which allow quantitative testing of the gating process. Both ungated and gated deliveries are investigated for different dose sizes, dose rates, and gating window times using a commercial treatment system (Varian Trilogy) together with a respiratory gating system [Varian Real-Time Position Management system]. Radiographic film measurements are used to study the geometric accuracy, where it is found that with both ungated and gated SS-IMRT deliveries the MLC leaf divergence away from planned is less than or equal to the MLC specified leaf tolerance value for all leafs (leaf tolerance being settable from 0.5-5 mm). Nevertheless, due to the MLC controller design, failure to define a specific leaf tolerance value suitable to the SS-IMRT plan can lead to undesired geometric effects, such as leaf motion of up to the maximum 5 mm leaf tolerance value occurring after the beam is turned on. In this case, gating may be advantageous over the ungated case, as it allows more time for the MLC to reach the intended leaf configuration. The dosimetric precision of gated SS-IMRT is investigated using ionization chamber methods. Compared with the ungated case, it is found that gating generally leads to increased dosimetric errors due to the interruption of the ''overshoot phenomena.'' With gating the average timing deviation for intermediate segments is found to be 27 ms, compared to 18 ms for the ungated case. For a plan delivered at 600 MU/min this would correspond to an average segment dose error of ∼0.27 MU and ∼0.18 MU for gated and ungated deliveries, respectively. The maximum dosimetric errors for individual intermediate segments are

  14. Analytical incorporation of fractionation effects in probabilistic treatment planning for intensity-modulated proton therapy.

    Science.gov (United States)

    Wahl, Niklas; Hennig, Philipp; Wieser, Hans-Peter; Bangert, Mark

    2018-04-01

    We show that it is possible to explicitly incorporate fractionation effects into closed-form probabilistic treatment plan analysis and optimization for intensity-modulated proton therapy with analytical probabilistic modeling (APM). We study the impact of different fractionation schemes on the dosimetric uncertainty induced by random and systematic sources of range and setup uncertainty for treatment plans that were optimized with and without consideration of the number of treatment fractions. The APM framework is capable of handling arbitrarily correlated uncertainty models including systematic and random errors in the context of fractionation. On this basis, we construct an analytical dose variance computation pipeline that explicitly considers the number of treatment fractions for uncertainty quantitation and minimization during treatment planning. We evaluate the variance computation model in comparison to random sampling of 100 treatments for conventional and probabilistic treatment plans under different fractionation schemes (1, 5, 30 fractions) for an intracranial, a paraspinal and a prostate case. The impact of neglecting the fractionation scheme during treatment planning is investigated by applying treatment plans that were generated with probabilistic optimization for 1 fraction in a higher number of fractions and comparing them to the probabilistic plans optimized under explicit consideration of the number of fractions. APM enables the construction of an analytical variance computation model for dose uncertainty considering fractionation at negligible computational overhead. It is computationally feasible (a) to simultaneously perform a robustness analysis for all possible fraction numbers and (b) to perform a probabilistic treatment plan optimization for a specific fraction number. The incorporation of fractionation assumptions for robustness analysis exposes a dose to uncertainty trade-off, i.e., the dose in the organs at risk is increased for a

  15. Treatment of Oral Cavity Squamous Cell Carcinoma With Adjuvant or Definitive Intensity-Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Sher, David J., E-mail: dsher@lroc.harvard.edu [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States); Thotakura, Vijaya [Department of Medical Oncology, Dana-Farber Cancer Institute and Department of Medicine, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Balboni, Tracy A. [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States); Norris, Charles M.; Haddad, Robert I.; Posner, Marshall R.; Lorch, Jochen [Department of Medical Oncology, Dana-Farber Cancer Institute and Department of Medicine, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Goguen, Laura A.; Annino, Donald J. [Department of Surgery, Division of Otolaryngology, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Tishler, Roy B. [Department of Radiation Oncology, Dana-Farber Cancer Institute and Brigham and Women' s Hospital, Boston, Massachusetts (United States)

    2011-11-15

    Purpose: The optimal management of oral cavity squamous cell carcinoma (OCSCC) typically involves surgical resection followed by adjuvant radiotherapy or chemoradiotherapy (CRT) in the setting of adverse pathologic features. Intensity-modulated radiation therapy (IMRT) is frequently used to treat oral cavity cancers, but published IMRT outcomes specific to this disease site are sparse. We report the Dana-Farber Cancer Institute experience with IMRT-based treatment for OCSCC. Methods and Materials: Retrospective study of all patients treated at Dana-Farber Cancer Institute for OCSCC with adjuvant or definitive IMRT between August 2004 and December 2009. The American Joint Committee on Cancer disease stage criteria distribution of this cohort included 5 patients (12%) with stage I; 10 patients (24%) with stage II (n = 10, 24%),; 14 patients (33%) with stage III (n = 14, 33%),; and 13 patients (31%) with stage IV. The primary endpoint was overall survival (OS); secondary endpoints were locoregional control (LRC) and acute and chronic toxicity. Results: Forty-two patients with OCSCC were included, 30 of whom were initially treated with surgical resection. Twenty-three (77%) of 30 surgical patients treated with adjuvant IMRT also received concurrent chemotherapy, and 9 of 12 (75%) patients treated definitively without surgery were treated with CRT or induction chemotherapy and CRT. With a median follow-up of 2.1 years (interquartile range, 1.1-3.1 years) for all patients, the 2-year actuarial rates of OS and LRC following adjuvant IMRT were 85% and 91%, respectively, and the comparable results for definitive IMRT were 63% and 64% for OS and LRC, respectively. Only 1 patient developed symptomatic osteoradionecrosis, and among patients without evidence of disease, 35% experienced grade 2 to 3 late dysphagia, with only 1 patient who was continuously gastrostomy-dependent. Conclusions: In this single-institution series, postoperative IMRT was associated with promising LRC

  16. Particle swarm optimizer for weighting factor selection in intensity-modulated radiation therapy optimization algorithms.

    Science.gov (United States)

    Yang, Jie; Zhang, Pengcheng; Zhang, Liyuan; Shu, Huazhong; Li, Baosheng; Gui, Zhiguo

    2017-01-01

    In inverse treatment planning of intensity-modulated radiation therapy (IMRT), the objective function is typically the sum of the weighted sub-scores, where the weights indicate the importance of the sub-scores. To obtain a high-quality treatment plan, the planner manually adjusts the objective weights using a trial-and-error procedure until an acceptable plan is reached. In this work, a new particle swarm optimization (PSO) method which can adjust the weighting factors automatically was investigated to overcome the requirement of manual adjustment, thereby reducing the workload of the human planner and contributing to the development of a fully automated planning process. The proposed optimization method consists of three steps. (i) First, a swarm of weighting factors (i.e., particles) is initialized randomly in the search space, where each particle corresponds to a global objective function. (ii) Then, a plan optimization solver is employed to obtain the optimal solution for each particle, and the values of the evaluation functions used to determine the particle's location and the population global location for the PSO are calculated based on these results. (iii) Next, the weighting factors are updated based on the particle's location and the population global location. Step (ii) is performed alternately with step (iii) until the termination condition is reached. In this method, the evaluation function is a combination of several key points on the dose volume histograms. Furthermore, a perturbation strategy - the crossover and mutation operator hybrid approach - is employed to enhance the population diversity, and two arguments are applied to the evaluation function to improve the flexibility of the algorithm. In this study, the proposed method was used to develop IMRT treatment plans involving five unequally spaced 6MV photon beams for 10 prostate cancer cases. The proposed optimization algorithm yielded high-quality plans for all of the cases, without human

  17. Rules of parotid gland dose variations and shift during intensity modulated radiation therapy for nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Wang, Wei; Yang, Haihua; Mi, Yucheng; Hu, Wei; Ding, Weijun; Xie, Youyou; Cai, Yujie; Chen, Xiaofeng

    2015-01-01

    To determine the position and dose delivery changes rules of parotid gland (PG) during the course of intensity modulated radiation therapy (IMRT) in nasopharyngeal carcinoma patients (NPC). One hundred and forty one competed tomography (CT) images from 47 NPC patients (three images for each patient were acquired before treatment, at the 15th and 25th fraction during the treatment) who underwent radical IMRT were selected for this study. A total of 70-76Gy at 2.12–2.3 Gy/fraction/d was given to the GTVnx in 33 fractions. The distances between the lateral/medial aspects of PG and midline (DLM and DMM) at the level of odontoid process were measured. The dose differences between plan and actual delivery were calculated. The volume reductions of PGs between fractions 15 and 25 were larger than those in the first 15 fractions (4.68 ± 3.23 cc vs. 2.46 ± 4.55 cc for the right PG and 5.96 ± 2.99 cc vs. 2.06 ± 2.99 cc for the left PG). However, the percentage of gland volume receiving ≥30 Gy (V30) of bilateral PGs decreased more significantly in the first 15 fractions than that between fractions 15 and 25 (5.61 ± 16.04% vs. 1.14 ± 21.54% for the right PG and 6.87 ± 15.58% vs. 0.81 ± 15.94% for the left PG). The gross tumor volume of the nasopharynx (GTVnx) decreased more significantly in the first 15 fractions than that between the 15th and 25th fraction (8.23 ± 13.61 cc vs. 3.30 ± 8.09 cc). The DMM of ipsilateral PGs reduced in the first 15 fractions (0.80 ± 2.96 mm) but increased between fraction 15 and 25 (−2.19 ± 3.96 mm). While ipsilateral PG shifted into target volume but shifted out target volume between fraction 15 and 25. Parotid glands V30 was correlated with GTVnx, GTVnx reduction and DMM reduction (p < 0.01). Our results indicate that the reduction of GTVnx leads to the positional change of the parotid gland, which results in more significant dose change of the parotid gland in the first 15 fractions than that between fraction 15 and 25

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

    Science.gov (United States)

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

    2012-02-01

    We present a method to include robustness in 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 (or errors) of the robust problem are modeled by pre-calculated dose-influence matrices for a nominal scenario and a number of pre-defined error scenarios (shifted patient positions, proton beam undershoot and overshoot). Objectives and constraints can be defined for the nominal scenario, thus characterizing nominal plan quality. A robustified objective represents the worst objective function value that can be realized for any of the error scenarios and thus provides a measure of plan robustness. The optimization method is based on a linear projection solver and is capable of handling large problem sizes resulting from a fine dose grid resolution, many scenarios, and a large number of proton pencil beams. A base-of-skull case is used to demonstrate the robust optimization method. It is demonstrated that the robust optimization method reduces the sensitivity of the treatment plan to setup and range errors to a degree that is not achieved by a safety margin approach. A chordoma case is analyzed in more detail to demonstrate the involved trade-offs between target underdose and brainstem sparing as well as robustness and nominal plan quality. The latter illustrates the advantage of MCO in the context of robust planning. For all cases examined, the robust optimization for

  19. Postoperative Intensity Modulated Radiation Therapy in High Risk Prostate Cancer: A Dosimetric Comparison

    International Nuclear Information System (INIS)

    Digesu, Cinzia; Cilla, Savino; De Gaetano, Andrea; Massaccesi, Mariangela; Macchia, Gabriella; Ippolito, Edy; Deodato, Francesco; Panunzi, Simona; Iapalucci, Chiara; Mattiucci, Gian Carlo; D'Angelo, Elisa; Padula, Gilbert D.A.; Valentini, Vincenzo; Cellini, Numa

    2011-01-01

    The aim of this study was to compare intensity-modulated radiation therapy (IMRT) with 3D conformal technique (3D-CRT), with respect to target coverage and irradiation of organs at risk for high dose postoperative radiotherapy (PORT) of the prostate fossa. 3D-CRT and IMRT treatment plans were compared with respect to dose to the rectum and bladder. The dosimetric comparison was carried out in 15 patients considering 2 different scenarios: (1) exclusive prostate fossa irradiation, and (2) pelvic node irradiation followed by a boost on the prostate fossa. In scenario (1), a 3D-CRT plan (box technique) and an IMRT plan were calculated and compared for each patient. In scenario (2), 3 treatment plans were calculated and compared for each patient: (a) 3D-CRT box technique for both pelvic (prophylactic nodal irradiation) and prostate fossa irradiation (3D-CRT only); (b) 3D-CRT box technique for pelvic irradiation followed by an IMRT boost to the prostatic fossa (hybrid 3D-CRT and IMRT); and (c) IMRT for both pelvic and prostate fossa irradiation (IMRT only). For exclusive prostate fossa irradiation, IMRT significantly reduced the dose to the rectum (lower Dmean, V50%, V75%, V90%, V100%, EUD, and NTCP) and the bladder (lower Dmean, V50%, V90%, EUD and NTCP). When prophylactic irradiation of the pelvis was also considered, plan C (IMRT only) performed better than plan B (hybrid 3D-CRT and IMRT) as respect to both rectum and bladder irradiation (reduction of Dmean, V50%, V75%, V90%, equivalent uniform dose [EUD], and normal tissue complication probability [NTCP]). Plan (b) (hybrid 3D-CRT and IMRT) performed better than plan (a) (3D-CRT only) with respect to dose to the rectum (lower Dmean, V75%, V90%, V100%, EUD, and NTCP) and the bladder (Dmean, EUD, and NTCP). Postoperative IMRT in prostate cancer significantly reduces rectum and bladder irradiation compared with 3D-CRT.

  20. Robustness Recipes for Minimax Robust Optimization in Intensity Modulated Proton Therapy for Oropharyngeal Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Voort, Sebastian van der [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam (Netherlands); Section of Nuclear Energy and Radiation Applications, Department of Radiation, Science and Technology, Delft University of Technology, Delft (Netherlands); Water, Steven van de [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam (Netherlands); Perkó, Zoltán [Section of Nuclear Energy and Radiation Applications, Department of Radiation, Science and Technology, Delft University of Technology, Delft (Netherlands); Heijmen, Ben [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam (Netherlands); Lathouwers, Danny [Section of Nuclear Energy and Radiation Applications, Department of Radiation, Science and Technology, Delft University of Technology, Delft (Netherlands); Hoogeman, Mischa, E-mail: m.hoogeman@erasmusmc.nl [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam (Netherlands)

    2016-05-01

    Purpose: We aimed to derive a “robustness recipe” giving the range robustness (RR) and setup robustness (SR) settings (ie, the error values) that ensure adequate clinical target volume (CTV) coverage in oropharyngeal cancer patients for given gaussian distributions of systematic setup, random setup, and range errors (characterized by standard deviations of Σ, σ, and ρ, respectively) when used in minimax worst-case robust intensity modulated proton therapy (IMPT) optimization. Methods and Materials: For the analysis, contoured computed tomography (CT) scans of 9 unilateral and 9 bilateral patients were used. An IMPT plan was considered robust if, for at least 98% of the simulated fractionated treatments, 98% of the CTV received 95% or more of the prescribed dose. For fast assessment of the CTV coverage for given error distributions (ie, different values of Σ, σ, and ρ), polynomial chaos methods were used. Separate recipes were derived for the unilateral and bilateral cases using one patient from each group, and all 18 patients were included in the validation of the recipes. Results: Treatment plans for bilateral cases are intrinsically more robust than those for unilateral cases. The required RR only depends on the ρ, and SR can be fitted by second-order polynomials in Σ and σ. The formulas for the derived robustness recipes are as follows: Unilateral patients need SR = −0.15Σ{sup 2} + 0.27σ{sup 2} + 1.85Σ − 0.06σ + 1.22 and RR=3% for ρ = 1% and ρ = 2%; bilateral patients need SR = −0.07Σ{sup 2} + 0.19σ{sup 2} + 1.34Σ − 0.07σ + 1.17 and RR=3% and 4% for ρ = 1% and 2%, respectively. For the recipe validation, 2 plans were generated for each of the 18 patients corresponding to Σ = σ = 1.5 mm and ρ = 0% and 2%. Thirty-four plans had adequate CTV coverage in 98% or more of the simulated fractionated treatments; the remaining 2 had adequate coverage in 97.8% and 97.9%. Conclusions: Robustness recipes were derived that can

  1. Origin of Tumor Recurrence After Intensity Modulated Radiation Therapy for Oropharyngeal Squamous Cell Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Raktoe, Sawan A.S. [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands); Dehnad, Homan, E-mail: h.dehnad@umcutrecht.nl [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands); Raaijmakers, Cornelis P.J. [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands); Braunius, Weibel [Department of ENT Head and Neck Surgery, University Medical Center Utrecht, Utrecht (Netherlands); Terhaard, Chris H.J. [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands)

    2013-01-01

    Purpose: To model locoregional recurrences of oropharyngeal squamous cell carcinomas (OSCC) treated with primary intensity modulated radiation therapy (IMRT) in order to find the origins from which recurrences grow and relate their location to original target volume borders. Methods and Materials: This was a retrospective analysis of OSCC treated with primary IMRT between January 2002 and December 2009. Locoregional recurrence volumes were delineated on diagnostic scans and coregistered rigidly with treatment planning computed tomography scans. Each recurrence was analyzed with two methods. First, overlapping volumes of a recurrence and original target were measured ('volumetric approach') and assessed as 'in-field', 'marginal', or 'out-field'. Then, the center of mass (COM) of a recurrence volume was assumed as the origin from where a recurrence expanded, the COM location was compared with original target volume borders and assessed as 'in-field', 'marginal', or 'out-field'. Results: One hundred thirty-one OSCC were assessed. For all patients alive at the end of follow-up, the mean follow-up time was 40 months (range, 12-83 months); 2 patients were lost to follow-up. The locoregional recurrence rate was 27%. Of all recurrences, 51% were local, 23% were regional, and 26% had both local and regional recurrences. Of all recurrences, 74% had imaging available for assessment. Regarding volumetric analysis of local recurrences, 15% were in-field gross tumor volume (GTV), and 65% were in-field clinical tumor volume (CTV). Using the COM approach, we found that 70% of local recurrences were in-field GTV and 90% were in-field CTV. Of the regional recurrences, 25% were volumetrically in-field GTV, and using the COM approach, we found 54% were in-field GTV. The COM of local out-field CTV recurrences were maximally 16 mm outside CTV borders, whereas for regional recurrences, this was 17 mm. Conclusions: The

  2. A GPU-accelerated and Monte Carlo-based intensity modulated proton therapy optimization system.

    Science.gov (United States)

    Ma, Jiasen; Beltran, Chris; Seum Wan Chan Tseung, Hok; Herman, Michael G

    2014-12-01

    Conventional spot scanning intensity modulated proton therapy (IMPT) treatment planning systems (TPSs) optimize proton spot weights based on analytical dose calculations. These analytical dose calculations have been shown to have severe limitations in heterogeneous materials. Monte Carlo (MC) methods do not have these limitations; however, MC-based systems have been of limited clinical use due to the large number of beam spots in IMPT and the extremely long calculation time of traditional MC techniques. In this work, the authors present a clinically applicable IMPT TPS that utilizes a very fast MC calculation. An in-house graphics processing unit (GPU)-based MC dose calculation engine was employed to generate the dose influence map for each proton spot. With the MC generated influence map, a modified least-squares optimization method was used to achieve the desired dose volume histograms (DVHs). The intrinsic CT image resolution was adopted for voxelization in simulation and optimization to preserve spatial resolution. The optimizations were computed on a multi-GPU framework to mitigate the memory limitation issues for the large dose influence maps that resulted from maintaining the intrinsic CT resolution. The effects of tail cutoff and starting condition were studied and minimized in this work. For relatively large and complex three-field head and neck cases, i.e., >100,000 spots with a target volume of ∼ 1000 cm(3) and multiple surrounding critical structures, the optimization together with the initial MC dose influence map calculation was done in a clinically viable time frame (less than 30 min) on a GPU cluster consisting of 24 Nvidia GeForce GTX Titan cards. The in-house MC TPS plans were comparable to a commercial TPS plans based on DVH comparisons. A MC-based treatment planning system was developed. The treatment planning can be performed in a clinically viable time frame on a hardware system costing around 45,000 dollars. The fast calculation and

  3. A GPU-accelerated and Monte Carlo-based intensity modulated proton therapy optimization system

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jiasen, E-mail: ma.jiasen@mayo.edu; Beltran, Chris; Seum Wan Chan Tseung, Hok; Herman, Michael G. [Department of Radiation Oncology, Division of Medical Physics, Mayo Clinic, 200 First Street Southwest, Rochester, Minnesota 55905 (United States)

    2014-12-15

    Purpose: Conventional spot scanning intensity modulated proton therapy (IMPT) treatment planning systems (TPSs) optimize proton spot weights based on analytical dose calculations. These analytical dose calculations have been shown to have severe limitations in heterogeneous materials. Monte Carlo (MC) methods do not have these limitations; however, MC-based systems have been of limited clinical use due to the large number of beam spots in IMPT and the extremely long calculation time of traditional MC techniques. In this work, the authors present a clinically applicable IMPT TPS that utilizes a very fast MC calculation. Methods: An in-house graphics processing unit (GPU)-based MC dose calculation engine was employed to generate the dose influence map for each proton spot. With the MC generated influence map, a modified least-squares optimization method was used to achieve the desired dose volume histograms (DVHs). The intrinsic CT image resolution was adopted for voxelization in simulation and optimization to preserve spatial resolution. The optimizations were computed on a multi-GPU framework to mitigate the memory limitation issues for the large dose influence maps that resulted from maintaining the intrinsic CT resolution. The effects of tail cutoff and starting condition were studied and minimized in this work. Results: For relatively large and complex three-field head and neck cases, i.e., >100 000 spots with a target volume of ∼1000 cm{sup 3} and multiple surrounding critical structures, the optimization together with the initial MC dose influence map calculation was done in a clinically viable time frame (less than 30 min) on a GPU cluster consisting of 24 Nvidia GeForce GTX Titan cards. The in-house MC TPS plans were comparable to a commercial TPS plans based on DVH comparisons. Conclusions: A MC-based treatment planning system was developed. The treatment planning can be performed in a clinically viable time frame on a hardware system costing around 45

  4. 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

  5. Evaluation of intra- and inter-fraction movement of the cervix during intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Haripotepornkul, Nora H.; Nath, Sameer K.; Scanderbeg, Daniel; Saenz, Cheryl; Yashar, Catheryn M.

    2011-01-01

    Background and purpose: To assess the degree of intra- and inter-fraction cervical motion throughout a course of intensity modulated radiation therapy (IMRT) for cervical cancer patients. Materials and methods: A retrospective study of 10 women with stage 1B1-3B cervical cancer diagnosed from September 2007 to July 2008 was conducted. All patients were treated with chemoradiation using IMRT followed by intracavitary brachytherapy. Pretreatment, patients had 2 seeds placed at a depth of 10 mm into the cervix. On-Board Imaging (OBI) was used to obtain anterior/posterior (AP) and lateral X-rays before and after each treatment. OBI images were rigidly aligned to baseline digitally reconstructed radiographs (DRRs), and movement of cervical seeds was determined in the lateral, vertical, and AP directions. Mean differences in cervical seed position and standard error of the mean (SEM) were calculated. Results: A total of 922 images were reviewed, with approximately 90 images per patient. The mean intra-fractional movement in cervical seed position in the lateral, vertical, and AP directions were 1.6 mm (SD ± 2.0), 2.6 mm (SD ± 2.4), and 2.9 mm (SD ± 2.7), respectively, with a range from 0 to 15 mm for each direction. The mean inter-fractional movement in the lateral, vertical, and AP directions were 1.9 mm (SD ± 1.9), 4.1 mm (SD ± 3.2), and 4.2 mm (SD ± 3.5), respectively, with a range from 0 to 18 mm for each direction. Conclusions: This is the first study to assess intra- and inter-fractional movement of the cervix using daily imaging before and after each fraction. Within and between radiation treatments, cervical motion averages approximately 3 mm in any given direction. However, maximal movement of the cervix can be as far as 18 mm from baseline. This wide range of motion needs to be accounted for when generating planning treatment volumes.

  6. Bone marrow-sparing intensity-modulated radiation therapy for Stage I seminoma

    International Nuclear Information System (INIS)

    Zilli, Thomas; Boudreau, Chantal; Doucet, Robert; Alizadeh, Moein; Lambert, Carole; Van Nguyen, Thu; Taussky, Daniel

    2011-01-01

    Background. A direct association between radiotherapy dose, side-effects and secondary cancers has been described in patients with seminoma. A treatment planning study was performed in order to compare computed tomography-based traditional radiotherapy (CT-tRT) versus bone marrow-sparing intensity-modulated radiation therapy (BMS-IMRT) in patients with Stage I seminoma. Material and methods. We optimized in 10 patients a CT-tRT and a BMS-IMRT treatment plan to deliver 20 Gy to the para-aortic nodes. CT-tRT and IMRT consisted of anteroposterior-posterioranterior parallel-opposed and seven non-opposed coplanar fields using 16 and 6-MV photon energies, respectively. Dose-Volume Histograms for clinical target volume (CTV), planning target volume (PTV) and organs at risk (OARs) were compared for both techniques using Wilcoxon matched-pair signed rank-test. Results. Dmean to CTV and PTV were similar for both techniques, even if CT-tRT showed a slightly improved target coverage in terms of PTV-D95% (19.7 vs. 19.5 Gy, p 0.005) and PTV-V95% (100 vs. 99.7%, p = 0.011) compared to BMS-IMRT. BMS-IMRT resulted in a significant reduction (5.2 Gy, p = 0.005) in the Dmean to the active bone marrow (ABM). The V100% and V75% of the OARs were reduced with BMS-IMRT by: ABM-V100% = 51.7% and ABM-V75% = 42.3%; bowel-V100% = 15.7% and bowel-V75% = 16.8%; stomach-V100% = 22% and stomach-V75% = 27.7%; pancreas-V100% = 37.1% and pancreas-V75% = 35.9% (p = 0.005 for all variables). Conclusions. BMS-IMRT reduces markedly the dose to the OARs compared to CT-tRT. This should translate into a reduction in acute and long-term toxicity, as well as into the risk of secondary solid and hematological cancers

  7. Intensity-Modulated Radiation Therapy in Oropharyngeal Carcinoma: Effect of Tumor Volume on Clinical Outcomes

    International Nuclear Information System (INIS)

    Lok, Benjamin H.; Setton, Jeremy; Caria, Nicola; Romanyshyn, Jonathan; Wolden, Suzanne L.; Zelefsky, Michael J.; Park, Jeffery; Rowan, Nicholas; Sherman, Eric J.; Fury, Matthew G.; Ho, Alan; Pfister, David G.; Wong, Richard J.; Shah, Jatin P.; Kraus, Dennis H.; Zhang, Zhigang; Schupak, Karen D.; Gelblum, Daphna Y.; Rao, Shyam D.; Lee, Nancy Y.

    2012-01-01

    Purpose: To analyze the effect of primary gross tumor volume (pGTV) and nodal gross tumor volume (nGTV) on treatment outcomes in patients treated with definitive intensity-modulated radiation therapy (IMRT) for oropharyngeal cancer (OPC). Methods and Materials: Between September 1998 and April 2009, a total of 442 patients with squamous cell carcinoma of the oropharynx were treated with IMRT with curative intent at our center. Thirty patients treated postoperatively and 2 additional patients who started treatment more than 6 months after diagnosis were excluded. A total of 340 patients with restorable treatment plans were included in this present study. The majority of the patients underwent concurrent platinum-based chemotherapy. The pGTV and nGTV were calculated using the original clinical treatment plans. Cox proportional hazards models and log-rank tests were used to evaluate the correlation between tumor volumes and overall survival (OS), and competing risks analysis tools were used to evaluate the correlation between local failure (LF), regional failure (RF), distant metastatic failure (DMF) vs. tumor volumes with death as a competing risk. Results: Median follow-up among surviving patients was 34 months (range, 5-67). The 2-year cumulative incidence of LF, RF and DF in this cohort of patients was 6.1%, 5.2%, and 12.2%, respectively. The 2-year OS rate was 88.6%. Univariate analysis determined pGTV and T-stage correlated with LF (p < 0.0001 and p = 0.004, respectively), whereas nGTV was not associated with RF. On multivariate analysis, pGTV and N-stage were independent risk factors for overall survival (p = 0.0003 and p = 0.0073, respectively) and distant control (p = 0.0008 and p = 0.002, respectively). Conclusions: In this cohort of patients with OPC treated with IMRT, pGTV was found to be associated with overall survival, local failure, and distant metastatic failure.

  8. Analysis of late toxicity in nasopharyngeal carcinoma patients treated with intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Zheng, YingJie; Han, Fei; Xiao, WeiWei; Xiang, YanQun; Lu, LiXia; Deng, XiaoWu; Cui, NianJi; Zhao, Chong

    2015-01-01

    To observe the late toxicities in nasopharyngeal carcinoma (NPC) patients who achieved long-term survival after intensity modulated radiation therapy (IMRT). 208 untreated NPC patients who received IMRT and survived more than five years with locoregional disease control and no metastasis were evaluated in this study. The prescription dose to the gross target volume of nasopharynx (GTVnx), positive neck lymph nodes (GTVnd), clinical target volume 1 (CTV1) and 2 (CTV2) was 68Gy/30f, 60-66Gy/30f, 60 Gy/30f and 54Gy/30f, respectively. The nasopharynx and upper neck targets were irradiated using IMRT, and the lower neck and supraclavicular fossae targets were irradiated using the half-beam technique with conventional irradiation. The late toxicities were evaluated according to the LENT/SOMA criteria of 1995. The median follow-up time was 78 months (60–96 months). The occurrence rates of cervical subcutaneous fibrosis, hearing loss, skin dystrophy, xerostomia, trismus, temporal lobe injury, cranial nerve damage, cataract, and brain stem injury induced by radiotherapy were 89.9%, 67.8%, 47.6%, 40.9%, 7.21%, 4.33%, 2.88%, 1.44%, and 0.48%, respectively. No spinal cord injury and mandible damage were found. Grade 3–4 late injuries were observed as follows: 1 (0.48%) skin dystrophy, 4 (1.92%) cervical subcutaneous fibrosis, 2 (0.96%) hearing loss, 2 (0.96%) cranial nerve palsy, and 1 (0.48%) temporal lobe necrosis. No grade 3–4 late injuries occurred in parotid, temporomandibular joints and eyes. Xerostomia decreased gradually over time and then showed only slight changes after 4 years. The change in the incisor distance stabilised by 1 year after RT, however, the incidence of hearing loss, skin dystrophy, subcutaneous fibrosis and nervous system injuries increased over time after RT. The late injuries in most NPC patients who had long-term survivals after IMRT are alleviated. Within the 5 years of follow-up, we found xerostomia decreased gradually; The change in the

  9. Application of intensity modulated radiation therapy for the cancer patients treatment in Bach Mai Hospital

    International Nuclear Information System (INIS)

    Mai Trong Khoa; Tran Dinh Ha; Le Chinh Dai; Nguyen Quang Hung; Vu Huu Khiem

    2011-01-01

    Intensity modulated radiotherapy (IMRT) is one of the modern techniques in cancer treatment, in which dose is delivered optimally into the shape of the tumor and minimally in surround benign tissues. In developed countries, this technique has been performed routinely by Linacs with MLC for tumors at the critical areas. In Vietnam, because of the wet climate, the use of Linacs with MLC is difficult to operate and maintain. However, IMRT can be implemented by Linacs without MLC via independent jaws, Jaws-only IMRT (JO-IMRT), in which beams are separated into many segments with different weights to optimize highest dose in the tumor and lowest dose in the surrounding health organs. Methods: We describe the new treatment technic application and compare it with normal radiotherapy method (3D-CRT). Results: From 7/2008, the Dep of Nuclear Medicine and Oncology at Bach Mai Hospital has been conducting JO-IMRT to treat cancer patients. Up to now, we have 81 cases treated by IMRT including head and neck cancers (NPC, larynx cancer, maxillary sinus cancer, brain tumor), cancers in the thorax (esophagus cancer, lung cancer, breast cancer), cancers in the pelvis (prostate cancer, cervical cancer, rectal cancer). On the average, beam number is from 5 to 9 and 5-9 segments per beam. Treatment time for a fraction is from 6 to 12 minutes with 2.25 Gy for CTV1 per day. Discrepancies of doses were below 3% (0.15 to 2.84%) between planning and practice. In plan, the preeminences with IMRT are clearly superior to 3D radiation therapy. In clinical, almost patients had good respond, whereas side effects were quite less than conventional radiotherapy. Conclusions: JO-IMRT is a modern technic with more advantage than normal 3D-CRT. It help radiation dose to concentrate maximally in treatment target while influence minimally for sensitive surrounding tissues. Another, it is a high technic to appropriate with the climatic condition in Vietnam. (author)

  10. Postoperative Intensity-Modulated Arc Therapy for Cervical and Endometrial Cancer: A Prospective Report on Toxicity

    International Nuclear Information System (INIS)

    Vandecasteele, Katrien; Tummers, Philippe; Makar, Amin; Eijkeren, Marc van; Delrue, Louke; Denys, Hannelore; Lambert, Bieke; Beerens, Anne-Sophie; Van den Broecke, Rudy; Lambein, Kathleen; Fonteyne, Valérie; De Meerleer, Gert

    2012-01-01

    Purpose: To report on toxicity after postoperative intensity-modulated arc therapy (IMAT) for cervical (CC) and endometrial cancer (EC). Methods and Materials: Twenty-four CC and 41 EC patients were treated with postoperative IMAT. If indicated, para-aortic lymph node irradiation (preventive or when affected, PALN) and/or concomitant cisplatin (40 mg/m², weekly) was administered. The prescribed dose for IMAT was 45 Gy (CC, 25 fractions) and 46 Gy (EC, 23 fractions), followed by a brachytherapeutic boost if possible. Radiation-related toxicity was assessed prospectively. The effect of concomitant cisplatin and PALN irradiation was evaluated. Results: Regarding acute toxicity (n = 65), Grade 3 and 2 acute gastrointestinal toxicity was observed in zero and 63% of patients (79% CC, 54% EC), respectively. Grade 3 and 2 acute genitourinary toxicity was observed in 1% and 18% of patients, respectively. Grade 2 (21%) and 3 (12%) hematologic toxicity (n = 41) occurred only in CC patients. Seventeen percent of CC patients and 2% of EC patients experienced Grade 2 fatigue and skin toxicity, respectively. Adding cisplatin led to an increase in Grade >2 nausea (57% vs. 9%; p = 0.01), Grade 2 nocturia (24% vs. 4%; p = 0.03), Grade ≥2 hematologic toxicity (38% vs. nil, p = 0.003), Grade ≥2 leukopenia (33% vs. nil, p = 0.009), and a strong trend toward more fatigue (14% vs. 2%; p = 0.05). Para-aortic lymph node irradiation led to an increase of Grade 2 nocturia (31% vs. 4%, p = 0.008) and a strong trend toward more Grade >2 nausea (44% vs. 18%; p = 0.052). Regarding late toxicity (n = 45), no Grade 3 or 4 late toxicity occurred. Grade 2 gastrointestinal toxicity, genitourinary toxicity, and fatigue occurred in 4%, 9%, and 1% of patients. Neither concomitant cisplatin nor PALN irradiation increased late toxicity rates. Conclusions: Postoperative IMAT for EC or CC is associated with low acute and late toxicity. Concomitant chemotherapy and PALN irradiation influences acute but

  11. An FMEA evaluation of intensity modulated radiation therapy dose delivery failures at tolerance criteria levels.

    Science.gov (United States)

    Faught, Jacqueline Tonigan; Balter, Peter A; Johnson, Jennifer L; Kry, Stephen F; Court, Laurence E; Stingo, Francesco C; Followill, David S

    2017-11-01

    The objective of this work was to assess both the perception of failure modes in Intensity Modulated Radiation Therapy (IMRT) when the linac is operated at the edge of tolerances given in AAPM TG-40 (Kutcher et al.) and TG-142 (Klein et al.) as well as the application of FMEA to this specific section of the IMRT process. An online survey was distributed to approximately 2000 physicists worldwide that participate in quality services provided by the Imaging and Radiation Oncology Core - Houston (IROC-H). The survey briefly described eleven different failure modes covered by basic quality assurance in step-and-shoot IMRT at or near TG-40 (Kutcher et al.) and TG-142 (Klein et al.) tolerance criteria levels. Respondents were asked to estimate the worst case scenario percent dose error that could be caused by each of these failure modes in a head and neck patient as well as the FMEA scores: Occurrence, Detectability, and Severity. Risk probability number (RPN) scores were calculated as the product of these scores. Demographic data were also collected. A total of 181 individual and three group responses were submitted. 84% were from North America. Most (76%) individual respondents performed at least 80% clinical work and 92% were nationally certified. Respondent medical physics experience ranged from 2.5 to 45 yr (average 18 yr). A total of 52% of individual respondents were at least somewhat familiar with FMEA, while 17% were not familiar. Several IMRT techniques, treatment planning systems, and linear accelerator manufacturers were represented. All failure modes received widely varying scores ranging from 1 to 10 for occurrence, at least 1-9 for detectability, and at least 1-7 for severity. Ranking failure modes by RPN scores also resulted in large variability, with each failure mode being ranked both most risky (1st) and least risky (11th) by different respondents. On average MLC modeling had the highest RPN scores. Individual estimated percent dose errors and severity

  12. Larynx-sparing techniques using intensity-modulated radiation therapy for oropharyngeal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bar Ad, Voichita, E-mail: voichita.bar-ad@jeffersonhospital.org [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Lin, Haibo [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Hwang, Wei-Ting [Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA (United States); Deville, Curtiland [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Dutta, Pinaki R. [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States); Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA (United States); Tochner, Zelig; Both, Stefan [Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA (United States)

    2012-01-01

    The purpose of the current study was to explore whether the laryngeal dose can be reduced by using 2 intensity-modulated radiation therapy (IMRT) techniques: whole-neck field IMRT technique (WF-IMRT) vs. junctioned IMRT (J-IMRT). The effect on planning target volumes (PTVs) coverage and laryngeal sparing was evaluated. WF-IMRT technique consisted of a single IMRT plan, including the primary tumor and the superior and inferior neck to the level of the clavicular heads. The larynx was defined as an organ at risk extending superiorly to cover the arytenoid cartilages and inferiorly to include the cricoid cartilage. The J-IMRT technique consisted of an IMRT plan for the primary tumor and the superior neck, matched to conventional antero-posterior opposing lower neck fields at the level of the thyroid notch. A central block was used for the anterior lower neck field at the level of the larynx to restrict the dose to the larynx. Ten oropharyngeal cancer cases were analyzed. Both the primary site and bilateral regional lymphatics were included in the radiotherapy targets. The averaged V95 for the PTV57.6 was 99.2% for the WF-IMRT technique compared with 97.4% (p = 0.02) for J-IMRT. The averaged V95 for the PTV64 was 99.9% for the WF-IMRT technique compared with 98.9% (p = 0.02) for J-IMRT and the averaged V95 for the PT70 was 100.0% for WF-IMRT technique compared with 99.5% (p = 0.04) for J-IMRT. The averaged mean laryngeal dose was 18 Gy with both techniques. The averaged mean doses within the matchline volumes were 69.3 Gy for WF-MRT and 66.2 Gy for J-IMRT (p = 0.03). The WF-IMRT technique appears to offer an optimal coverage of the target volumes and a mean dose to the larynx similar with J-IMRT and should be further evaluated in clinical trials.

  13. Treatment of Oral Cavity Squamous Cell Carcinoma With Adjuvant or Definitive Intensity-Modulated Radiation Therapy

    International Nuclear Information System (INIS)

    Sher, David J.; Thotakura, Vijaya; Balboni, Tracy A.; Norris, Charles M.; Haddad, Robert I.; Posner, Marshall R.; Lorch, Jochen; Goguen, Laura A.; Annino, Donald J.; Tishler, Roy B.

    2011-01-01

    Purpose: The optimal management of oral cavity squamous cell carcinoma (OCSCC) typically involves surgical resection followed by adjuvant radiotherapy or chemoradiotherapy (CRT) in the setting of adverse pathologic features. Intensity-modulated radiation therapy (IMRT) is frequently used to treat oral cavity cancers, but published IMRT outcomes specific to this disease site are sparse. We report the Dana-Farber Cancer Institute experience with IMRT-based treatment for OCSCC. Methods and Materials: Retrospective study of all patients treated at Dana-Farber Cancer Institute for OCSCC with adjuvant or definitive IMRT between August 2004 and December 2009. The American Joint Committee on Cancer disease stage criteria distribution of this cohort included 5 patients (12%) with stage I; 10 patients (24%) with stage II (n = 10, 24%),; 14 patients (33%) with stage III (n = 14, 33%),; and 13 patients (31%) with stage IV. The primary endpoint was overall survival (OS); secondary endpoints were locoregional control (LRC) and acute and chronic toxicity. Results: Forty-two patients with OCSCC were included, 30 of whom were initially treated with surgical resection. Twenty-three (77%) of 30 surgical patients treated with adjuvant IMRT also received concurrent chemotherapy, and 9 of 12 (75%) patients treated definitively without surgery were treated with CRT or induction chemotherapy and CRT. With a median follow-up of 2.1 years (interquartile range, 1.1–3.1 years) for all patients, the 2-year actuarial rates of OS and LRC following adjuvant IMRT were 85% and 91%, respectively, and the comparable results for definitive IMRT were 63% and 64% for OS and LRC, respectively. Only 1 patient developed symptomatic osteoradionecrosis, and among patients without evidence of disease, 35% experienced grade 2 to 3 late dysphagia, with only 1 patient who was continuously gastrostomy-dependent. Conclusions: In this single-institution series, postoperative IMRT was associated with promising LRC

  14. Failure Patterns After Hemithoracic Pleural Intensity Modulated Radiation Therapy for Malignant Pleural Mesothelioma

    Energy Technology Data Exchange (ETDEWEB)

    Rimner, Andreas, E-mail: rimnera@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Spratt, Daniel E. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Zauderer, Marjorie G. [Department of Medicine, Thoracic Oncology Service, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medical College, New York, New York (United States); Rosenzweig, Kenneth E. [Department of Radiation Oncology, Mount Sinai Medical Center, New York, New York (United States); Wu, Abraham J.; Foster, Amanda [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Yorke, Ellen D. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Adusumilli, Prasad; Rusch, Valerie W. [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Krug, Lee M. [Department of Medicine, Thoracic Oncology Service, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medical College, New York, New York (United States)

    2014-10-01

    Purpose: We previously reported our technique for delivering intensity modulated radiation therapy (IMRT) to the entire pleura while attempting to spare the lung in patients with malignant pleural mesothelioma (MPM). Herein, we report a detailed pattern-of-failure analysis in patients with MPM who were unresectable or underwent pleurectomy/decortication (P/D), uniformly treated with hemithoracic pleural IMRT. Methods and Materials: Sixty-seven patients with MPM were treated with definitive or adjuvant hemithoracic pleural IMRT between November 2004 and May 2013. Pretreatment imaging, treatment plans, and posttreatment imaging were retrospectively reviewed to determine failure location(s). Failures were categorized as in-field (within the 90% isodose line), marginal (<90% and ≥50% isodose lines), out-of-field (outside the 50% isodose line), or distant. Results: The median follow-up was 24 months from diagnosis and the median time to in-field local failure from the end of RT was 10 months. Forty-three in-field local failures (64%) were found with a 1- and 2-year actuarial failure rate of 56% and 74%, respectively. For patients who underwent P/D versus those who received a partial pleurectomy or were deemed unresectable, the median time to in-field local failure was 14 months versus 6 months, respectively, with 1- and 2-year actuarial in-field local failure rates of 43% and 60% versus 66% and 83%, respectively (P=.03). There were 13 marginal failures (19%). Five of the marginal failures (38%) were located within the costomediastinal recess. Marginal failures decreased with increasing institutional experience (P=.04). Twenty-five patients (37%) had out-of-field failures. Distant failures occurred in 32 patients (48%). Conclusions: After hemithoracic pleural IMRT, local failure remains the dominant form of failure pattern. Patients treated with adjuvant hemithoracic pleural IMRT after P/D experience a significantly longer time to local and distant failure than

  15. Bladder radiotherapy treatment: A retrospective comparison of 3-dimensional conformal radiotherapy, intensity-modulated radiation therapy, and volumetric-modulated arc therapy plans

    Energy Technology Data Exchange (ETDEWEB)

    Pasciuti, Katia, E-mail: k.pasciuti@virgilio.it [Department of Radiotherapy Physics, Royal Free Hospital, London (United Kingdom); Kuthpady, Shrinivas [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom); Anderson, Anne; Best, Bronagh [Department of Radiotherapy Physics, Royal Free Hospital, London (United Kingdom); Waqar, Saleem; Chowdhury, Subhra [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom)

    2017-04-01

    To examine tumor's and organ's response when different radiotherapy plan techniques are used. Ten patients with confirmed bladder tumors were first treated using 3-dimensional conformal radiotherapy (3DCRT) and subsequently the original plans were re-optimized using the intensity-modulated radiation treatment (IMRT) and volumetric-modulated arc therapy (VMAT)-techniques. Targets coverage in terms of conformity and homogeneity index, TCP, and organs' dose limits, including integral dose analysis were evaluated. In addition, MUs and treatment delivery times were compared. Better minimum target coverage (1.3%) was observed in VMAT plans when compared to 3DCRT and IMRT ones confirmed by a statistically significant conformity index (CI) results. Large differences were observed among techniques in integral dose results of the femoral heads. Even if no statistically significant differences were reported in rectum and tissue, a large amount of energy deposition was observed in 3DCRT plans. In any case, VMAT plans provided better organs and tissue sparing confirmed also by the normal tissue complication probability (NTCP) analysis as well as a better tumor control probability (TCP) result. Our analysis showed better overall results in planning using VMAT techniques. Furthermore, a total time reduction in treatment observed among techniques including gantry and collimator rotation could encourage using the more recent one, reducing target movements and patient discomfort.

  16. Comparative analysis of {sup 60}Co intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Christopher [Sun Nuclear Corporation, 425-A Pineda Court, Melbourne, FL 32940 (United States); Romeijn, H Edwin; Lynch, Bart; Dempsey, James F [Department of Radiation Oncology, University of Florida, Gainesville, FL 32610-0385 (United States); Men, Chunhua [Department of Industrial and Systems Engineering, University of Florida, Gainesville, FL 32611-6595 (United States); Aleman, Dionne M [Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario (Canada)], E-mail: chrisfox@sunnuclear.com, E-mail: romeijn@ise.ufl.edu, E-mail: lynchb@ufl.edu, E-mail: chhmen@ufl.edu, E-mail: aleman@mie.utoronto.edu, E-mail: dempsey@ufl.edu

    2008-06-21

    In this study, we perform a scientific comparative analysis of using {sup 60}Co beams in intensity-modulated radiation therapy (IMRT). In particular, we evaluate the treatment plan quality obtained with (i) 6 MV, 18 MV and {sup 60}Co IMRT; (ii) different numbers of static multileaf collimator (MLC) delivered {sup 60}Co beams and (iii) a helical tomotherapy {sup 60}Co beam geometry. We employ a convex fluence map optimization (FMO) model, which allows for the comparison of plan quality between different beam energies and configurations for a given case. A total of 25 clinical patient cases that each contain volumetric CT studies, primary and secondary delineated targets, and contoured structures were studied: 5 head-and-neck (H and N), 5 prostate, 5 central nervous system (CNS), 5 breast and 5 lung cases. The DICOM plan data were anonymized and exported to the University of Florida optimized radiation therapy (UFORT) treatment planning system. The FMO problem was solved for each case for 5-71 equidistant beams as well as a helical geometry for H and N, prostate, CNS and lung cases, and for 3-7 equidistant beams in the upper hemisphere for breast cases, all with 6 MV, 18 MV and {sup 60}Co dose models. In all cases, 95% of the target volumes received at least the prescribed dose with clinical sparing criteria for critical organs being met for all structures that were not wholly or partially contained within the target volume. Improvements in critical organ sparing were found with an increasing number of equidistant {sup 60}Co beams, yet were marginal above 9 beams for H and N, prostate, CNS and lung. Breast cases produced similar plans for 3-7 beams. A helical {sup 60}Co beam geometry achieved similar plan quality as static plans with 11 equidistant {sup 60}Co beams. Furthermore, 18 MV plans were initially found not to provide the same target coverage as 6 MV and {sup 60}Co plans; however, adjusting the trade-offs in the optimization model allowed equivalent target

  17. Impact of geometric uncertainties on dose calculations for intensity modulated radiation therapy of prostate cancer

    Science.gov (United States)

    Jiang, Runqing

    Intensity-modulated radiation therapy (IMRT) uses non-uniform beam intensities within a radiation field to provide patient-specific dose shaping, resulting in a dose distribution that conforms tightly to the planning target volume (PTV). Unavoidable geometric uncertainty arising from patient repositioning and internal organ motion can lead to lower conformality index (CI) during treatment delivery, a decrease in tumor control probability (TCP) and an increase in normal tissue complication probability (NTCP). The CI of the IMRT plan depends heavily on steep dose gradients between the PTV and organ at risk (OAR). Geometric uncertainties reduce the planned dose gradients and result in a less steep or "blurred" dose gradient. The blurred dose gradients can be maximized by constraining the dose objective function in the static IMRT plan or by reducing geometric uncertainty during treatment with corrective verification imaging. Internal organ motion and setup error were evaluated simultaneously for 118 individual patients with implanted fiducials and MV electronic portal imaging (EPI). A Gaussian probability density function (PDF) is reasonable for modeling geometric uncertainties as indicated by the 118 patients group. The Gaussian PDF is patient specific and group standard deviation (SD) should not be used for accurate treatment planning for individual patients. In addition, individual SD should not be determined or predicted from small imaging samples because of random nature of the fluctuations. Frequent verification imaging should be employed in situations where geometric uncertainties are expected. Cumulative PDF data can be used for re-planning to assess accuracy of delivered dose. Group data is useful for determining worst case discrepancy between planned and delivered dose. The margins for the PTV should ideally represent true geometric uncertainties. The measured geometric uncertainties were used in this thesis to assess PTV coverage, dose to OAR, equivalent

  18. Breast-conserving radiation therapy using combined electron and intensity-modulated radiotherapy technique

    International Nuclear Information System (INIS)

    Li, J.G.; Williams, S.S.; Goffinet, D.R.; Boer, A.L.; Xing, L.

    2000-01-01

    An electron beam with appropriate energy was combined with four intensity modulated photon beams. The direction of the electron beam was chosen to be tilted 10-20 laterally from the anteroposterior direction. Two of the intensity-modulated photon beams had the same gantry angles as the conventional tangential fields, whereas the other two beams were rotated 15-25' toward the anteroposterior directions from the first two photon beams. An iterative algorithm was developed which optimizes the weight of the electron beam as well as the fluence profiles of the photon beams for a given patient. Two breast cancer patients with early-stage breast tumors were planned with the new technique and the results were compared with those from 3D planning using tangential fields as well as 9-field intensity-modulated radiotherapy (IMRT) techniques. The combined electron and IMRT plans showed better dose conformity to the target with significantly reduced dose to the ipsilateral lung and, in the case of the left-breast patient, reduced dose to the heart, than the tangential field plans. In both the right-sided and left-sided breast plans, the dose to other normal structures was similar to that from conventional plans and was much smaller than that from the 9-field IMRT plans. The optimized electron beam provided between 70 to 80% of the prescribed dose at the depth of maximum dose of the electron beam. The combined electron and IMRT technique showed improvement over the conventional treatment technique using tangential fields with reduced dose to the ipsilateral lung and the heart. The customized beam directions of the four IMRT fields also kept the dose to other critical structures to a minimum. (author)

  19. A Prospective Comparison of the Effects of Interfractional Variations on Proton Therapy and Intensity Modulated Radiation Therapy for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Moteabbed, Maryam, E-mail: mmoteabbed@partners.org; Trofimov, Alexei; Sharp, Gregory C.; Wang, Yi; Zietman, Anthony L.; Efstathiou, Jason A.; Lu, Hsiao-Ming

    2016-05-01

    Purpose: To quantify and compare the impact of interfractional setup and anatomic variations on proton therapy (PT) and intensity modulated radiation therapy (IMRT) for prostate cancer. Methods and Materials: Twenty patients with low-risk or intermediate-risk prostate cancer randomized to receive passive-scattering PT (n=10) and IMRT (n=10) were selected. For both modalities, clinical treatment plans included 50.4 Gy(RBE) to prostate and proximal seminal vesicles, and prostate-only boost to 79.2 Gy(RBE) in 1.8 Gy(RBE) per fraction. Implanted fiducials were used for prostate localization and endorectal balloons were used for immobilization. Patients in PT and IMRT arms received weekly computed tomography (CT) and cone beam CT (CBCT) scans, respectively. The planned dose was recalculated on each weekly image, scaled, and mapped onto the planning CT using deformable registration. The resulting accumulated dose distribution over the entire treatment course was compared with the planned dose using dose-volume histogram (DVH) and γ analysis. Results: The target conformity index remained acceptable after accumulation. The largest decrease in the average prostate D{sub 98} was 2.2 and 0.7 Gy for PT and IMRT, respectively. On average, the mean dose to bladder increased by 3.26 ± 7.51 Gy and 1.97 ± 6.84 Gy for PT and IMRT, respectively. These values were 0.74 ± 2.37 and 0.56 ± 1.90 for rectum. Differences between changes in DVH indices were not statistically significant between modalities. All volume indices remained within the protocol tolerances after accumulation. The average pass rate for the γ analysis, assuming tolerances of 3 mm and 3%, for clinical target volume, bladder, rectum, and whole patient for PT/IMRT were 100/100, 92.6/99, 99.2/100, and 97.2/99.4, respectively. Conclusion: The differences in target coverage and organs at risk dose deviations for PT and IMRT were not statistically significant under the guidelines of this protocol.

  20. Verification of dosimetric commissioning accuracy of intensity modulated radiation therapy and volumetric modulated arc therapy delivery using task Group-119 guidelines

    Directory of Open Access Journals (Sweden)

    Karunakaran Kaviarasu

    2017-01-01

    Full Text Available Aim: The purpose of this study is to verify the accuracy of the commissioning of intensity-modulated radiation therapy (IMRT and volumetric-modulated arc therapy (VMAT based on the recommendation of the American Association of Physicists in Medicine Task Group 119 (TG-119. Materials and Methods: TG-119 proposes a set of clinical test cases to verify the accuracy of IMRT planning and delivery system. For these test cases, we generated two sets of treatment plans, the first plan using 7–9 IMRT fields and a second plan utilizing two-arc VMAT technique for both 6 MV and 15 MV photon beams. The template plans of TG-119 were optimized and calculated by Varian Eclipse Treatment Planning System (version 13.5. Dose prescription and planning objectives were set according to the TG-119 goals. The point dose (mean dose to the contoured chamber volume at the specified positions/locations was measured using compact (CC-13 ion chamber. The composite planar dose was measured with IMatriXX Evaluation 2D array with OmniPro IMRT Software (version 1.7b. The per-field relative gamma was measured using electronic portal imaging device in a way similar to the routine pretreatment patient-specific quality assurance. Results: Our planning results are compared with the TG-119 data. Point dose and fluence comparison data where within the acceptable confident limit. Conclusion: From the obtained data in this study, we conclude that the commissioning of IMRT and VMAT delivery were found within the limits of TG-119.

  1. Verification of Dosimetric Commissioning Accuracy of Intensity Modulated Radiation Therapy and Volumetric Modulated Arc Therapy Delivery using Task Group-119 Guidelines.

    Science.gov (United States)

    Kaviarasu, Karunakaran; Nambi Raj, N Arunai; Hamid, Misba; Giri Babu, A Ananda; Sreenivas, Lingampally; Murthy, Kammari Krishna

    2017-01-01

    The purpose of this study is to verify the accuracy of the commissioning of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) based on the recommendation of the American Association of Physicists in Medicine Task Group 119 (TG-119). TG-119 proposes a set of clinical test cases to verify the accuracy of IMRT planning and delivery system. For these test cases, we generated two sets of treatment plans, the first plan using 7-9 IMRT fields and a second plan utilizing two-arc VMAT technique for both 6 MV and 15 MV photon beams. The template plans of TG-119 were optimized and calculated by Varian Eclipse Treatment Planning System (version 13.5). Dose prescription and planning objectives were set according to the TG-119 goals. The point dose (mean dose to the contoured chamber volume) at the specified positions/locations was measured using compact (CC-13) ion chamber. The composite planar dose was measured with IMatriXX Evaluation 2D array with OmniPro IMRT Software (version 1.7b). The per-field relative gamma was measured using electronic portal imaging device in a way similar to the routine pretreatment patient-specific quality assurance. Our planning results are compared with the TG-119 data. Point dose and fluence comparison data where within the acceptable confident limit. From the obtained data in this study, we conclude that the commissioning of IMRT and VMAT delivery were found within the limits of TG-119.

  2. Light intensity modulation in phototherapy

    Science.gov (United States)

    Lukyanovich, P. A.; Zon, B. A.; Kunin, A. A.; Pankova, S. N.

    2015-04-01

    A hypothesis that blocking ATP synthesis is one of the main causes of the stimulating effect is considered based on analysis of the primary photostimulation mechanisms. The light radiation intensity modulation is substantiated and the estimates of such modulation parameters are made. An explanation is offered to the stimulation efficiency decrease phenomenon at the increase of the radiation dose during the therapy. The results of clinical research of the medical treatment in preventive dentistry are presented depending on the spectrum and parameters of the light flux modulation.

  3. Intensity modulated conformal radiotherapy

    International Nuclear Information System (INIS)

    Noel, Georges; Moty-Monnereau, Celine; Meyer, Aurelia; David, Pauline; Pages, Frederique; Muller, Felix; Lee-Robin, Sun Hae; David, Denis Jean

    2006-12-01

    This publication reports the assessment of intensity-modulated conformal radiotherapy (IMCR). This assessment is based on a literature survey which focussed on indications, efficiency and safety on the short term, on the risk of radio-induced cancer on the long term, on the role in the therapeutic strategy, on the conditions of execution, on the impact on morbidity-mortality and life quality, on the impact on the health system and on public health policies and program. This assessment is also based on the opinion of a group of experts regarding the technical benefit of IMCR, its indications depending on the cancer type, safety in terms of radio-induced cancers, and conditions of execution. Before this assessment, the report thus indicates indications for which the use of IMCR can be considered as sufficient or not determined. It also proposes a technical description of IMCR and helical tomo-therapy, discusses the use of this technique for various pathologies or tumours, analyses the present situation of care in France, and comments the identification of this technique in foreign classifications

  4. Comparison of a new noncoplanar intensity-modulated radiation therapy technique for craniospinal irradiation with 3 coplanar techniques

    DEFF Research Database (Denmark)

    Hansen, Anders T; Lukacova, Slavka; Lassen-Ramshad, Yasmin A.

    2015-01-01

    When standard conformal x-ray technique for craniospinal irradiation is used, it is a challenge to achieve satisfactory dose coverage of the target including the area of the cribriform plate, while sparing organs at risk. We present a new intensity-modulated radiation therapy (IMRT), noncoplanar...... patient using the noncoplanar IMRT-based technique, a coplanar IMRT-based technique, and a coplanar volumetric-modulated arch therapy (VMAT) technique. Dosimetry data for all patients were compared with the corresponding data from the conventional treatment plans. The new noncoplanar IMRT technique...... substantially reduced the mean dose to organs at risk compared with the standard radiation technique. The 2 other coplanar techniques also reduced the mean dose to some of the critical organs. However, this reduction was not as substantial as the reduction obtained by the noncoplanar technique. Furthermore...

  5. Dosimetric analysis of testicular doses in prostate intensity-modulated and volumetric-modulated arc radiation therapy at different energy levels

    Energy Technology Data Exchange (ETDEWEB)

    Onal, Cem, E-mail: hcemonal@hotmail.com; Arslan, Gungor; Dolek, Yemliha; Efe, Esma

    2016-01-01

    The aim of this study is to evaluate the incidental testicular doses during prostate radiation therapy with intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc radiotherapy (VMAT) at different energies. Dosimetric data of 15 patients with intermediate-risk prostate cancer who were treated with radiotherapy were analyzed. The prescribed dose was 78 Gy in 39 fractions. Dosimetric analysis compared testicular doses generated by 7-field intensity-modulated radiotherapy and volumetric-modulated arc radiotherapy with a single arc at 6, 10, and 15 MV energy levels. Testicular doses calculated from the treatment planning system and doses measured from the detectors were analyzed. Mean testicular doses from the intensity-modulated radiotherapy and volumetric-modulated arc radiotherapy per fraction calculated in the treatment planning system were 16.3 ± 10.3 cGy vs 21.5 ± 11.2 cGy (p = 0.03) at 6 MV, 13.4 ± 10.4 cGy vs 17.8 ± 10.7 cGy (p = 0.04) at 10 MV, and 10.6 ± 8.5 cGy vs 14.5 ± 8.6 cGy (p = 0.03) at 15 MV, respectively. Mean scattered testicular doses in the phantom measurements were 99.5 ± 17.2 cGy, 118.7 ± 16.4 cGy, and 193.9 ± 14.5 cGy at 6, 10, and 15 MV, respectively, in the intensity-modulated radiotherapy plans. In the volumetric-modulated arc radiotherapy plans, corresponding testicular doses per course were 90.4 ± 16.3 cGy, 103.6 ± 16.4 cGy, and 139.3 ± 14.6 cGy at 6, 10, and 15 MV, respectively. In conclusions, this study was the first to measure the incidental testicular doses by intensity-modulated radiotherapy and volumetric-modulated arc radiotherapy plans at different energy levels during prostate-only irradiation. Higher photon energy and volumetric-modulated arc radiotherapy plans resulted in higher incidental testicular doses compared with lower photon energy and intensity-modulated radiotherapy plans.

  6. Multimodal hypoxia imaging and intensity modulated radiation therapy for unresectable non-small-cell lung cancer: the HIL trial

    Directory of Open Access Journals (Sweden)

    Askoxylakis Vasileios

    2012-09-01

    Full Text Available Abstract Background Radiotherapy, preferably combined with chemotherapy, is the treatment standard for locally advanced, unresectable non-small cell lung cancer (NSCLC. The tumor response to different therapy protocols is variable, with hypoxia known to be a major factor that negatively influences treatment effectiveness. Visualisation of tumor hypoxia prior to the use of modern radiation therapy strategies, such as intensity modulated radiation therapy (IMRT, might allow optimized dose applications to the target volume, leading to improvement of therapy outcome. 18 F-fluoromisonidazole dynamic positron emission tomography and computed tomography (18 F-FMISO dPET-CT and functional magnetic resonance imaging (functional MRI are attractive options for imaging tumor hypoxia. Methods/design The HIL trial is a single centre study combining multimodal hypoxia imaging with 18 F-FMISO dPET-CT and functional MRI, with intensity modulated radiation therapy (IMRT in patients with inoperable stage III NSCLC. 15 patients will be recruited in the study. All patients undergo initial FDG PET-CT and serial 18 F-FMISO dPET-CT and functional MRI before treatment, at week 5 of radiotherapy and 6 weeks post treatment. Radiation therapy is performed as inversely planned IMRT based on 4D-CT. Discussion Primary objectives of the trial are to characterize the correlation of 18 F-FMISO dPET-CT and functional MRI for tumor hypoxia imaging in NSCLC and evaluate possible effects of radiation therapy on tumor re-oxygenation. Further objectives include the generation of data regarding the prognostic value of 18 F-FMISO dPET-CT and functional MRI for locoregional control, progression free survival and overall survival of NSCLC treated with IMRT, which will form the basis for larger clinical trials focusing on possible interactions between tumor oxygenation and radiotherapy outcome. Trial registration The ClinicalTrials.gov protocol ID is NCT01617980

  7. Design, simulation and manufacture of a multi leaf collimator to confirm the target volumes in intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Kamali-Asl, A.; Batooli, A. H.; Harriri, S.; Salman-Rezaee, F.; Shahmardan, F.; Yavari, L.

    2010-01-01

    Intensity modulated radiation therapy is one of the cancer treatment methods. It is important to selectively aim at the target in this way, which can be performed using a multi leaf collimator. Materials and Methods: In order to specifically irradiate the target volume in radiotherapy to reduce the patient absorbed dose, the use of multi leaf collimator has been investigated in this work. Design and simulation of an multi leaf collimator was performed by a Monte Carlo method and the optimum material for manufacturing the leaves was determined using MCNP4C. After image processing (CT or MRI) in this system, the tumor configuration is determined. Then the linear accelerator is switched on and the beam irradiates the cancerous cells. When the multi leaf collimator leaves receive a command from the micro controller, they start to move and absorb the radiation and modulate its intensity. Consequently, the tumor receives maximum intensity of radiation but minimum intensity is delivered to healthy tissues. Results: According to the simulations and calculations, the best material to manufacture the leaves from is tungsten alloy containing copper and nickel which absorbs a large amount of the radiation; by using a 8.65 cm thickness of alloy, 10.55% of radiation will transmit through the leaves. Discussion and Conclusion: Lead blocks are conventionally used in radiotherapy. However, they have some problems like cost, storage and manufacture for every patient. Certainly, the multi leaf collimator is the most efficient device to specifically irradiate the tumor in Intensity modulated radiation therapy. Furthermore, it facilitates treating the target in different views by rotation around the patient. Thus the patient's absorbed dose will decrease and the tumor will receive maximum dose.

  8. Simultaneous integrated boost-intensity modulated radiation therapy for inoperable hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Hyun; Park, Joong-Won; Kim, Yeon-Joo; Kim, Bo Hyun; Woo, Sang Myung; Moon, Sung Ho; Kim, Sang Soo; Lee, Woo Jin; Kim, Dae Yong; Kim, Chang-Min [National Cancer Center, Center for Liver Cancer, Research Institute and Hospital, Goyang-si, Gyeonggi-do (Korea, Republic of)

    2014-10-15

    The aim of this work was to evaluate the clinical efficacy and safety of simultaneous integrated boost-intensity modulated radiation therapy (SIB-IMRT) in patients with inoperable hepatocellular carcinoma (HCC). A total of 53 patients with inoperable HCC underwent SIB-IMRT using two dose-fractionation schemes, depending on the proximity of gastrointestinal structures. The 41 patients in the low dose-fractionation (LD) group, with internal target volume (ITV) < 1 cm from gastrointestinal structures, received total doses of 55 and 44 Gy in 22 fractions to planning target volume 1 (PTV1) and 2 (PTV2), respectively. The 12 patients in the high dose-fractionation (HD) group, with ITV ≥ 1 cm from gastrointestinal structures, received total doses of 66 and 55 Gy in 22 fractions to the PTV1 and PTV2, respectively. Overall, treatment was well tolerated, with no grade > 3 toxicity. The LD group had larger sized tumors (median: 6 vs. 3.4 cm) and greater frequencies of vascular invasion (80.6 vs. 16.7 %) than patients in the HD group (p < 0.05 each). The median overall survival (OS) was 25.1 months and the actuarial 2-year local progression-free survival (LPFS), relapse-free survival (RFS), and OS rates were 67.3, 14.7, and 54.7 %, respectively. The HD group tended to show better tumor response (100 vs. 62.2 %, p = 0.039) and 2-year LPFS (85.7 vs. 59 %, p = 0.119), RFS (38.1 vs. 7.3 %, p = 0.063), and OS (83.3 vs. 44.3 %, p = 0.037) rates than the LD group. Multivariate analysis showed that tumor response was significantly associated with OS. SIB-IMRT is feasible and safe for patients with inoperable HCC. (orig.) [German] Ziel der Arbeit war es, die klinische Wirksamkeit und die Sicherheit der intensitaetsmodulierten Radiotherapie mit simultanem integriertem Boost (SIB-IMRT) fuer Patienten mit einem inoperablen hepatozellulaeren Karzinom (HCC) zu evaluieren. Bei 53 Patienten mit inoperablem HCC wurden zwei unterschiedliche Dosierungskonzepte je nach Lagebeziehung des

  9. A novel conformity index for intensity modulated radiation therapy plan evaluation

    International Nuclear Information System (INIS)

    Cheung, Fion W. K.; Law, Maria Y. Y.

    2012-01-01

    Purpose: Intensity modulated radiation therapy (IMRT) has gained popularity in the treatment of cancers. Manual evaluation of IMRT plans for head-and-neck cancers has been especially challenging necessitating efficient and objective assessment tools. In this work, the authors address this issue by developing a personalized conformity index (CI) for comparison of IMRT plans for head-and-neck cancers and evaluating its plan quality discerning power in comparison with other widely used CIs. Methods: A two-dimensional CI with dose and distance incorporated (CI DD ) was developed using the MATLAB program language, to quantify the planning target volume (PTV) coverage. Valuable information contained in the digital imaging and communication in medicine (DICOM) RT objects were harvested for computation of each of the CI DD components. Apart from the dose penalty factor, a distance-based exponential function was employed by varying the penalty weight associated with the location of cold spots within the PTV. With the goal of deriving a customized penalty factor, the distances between individual pixel and its nearest PTV boundary was found. Using the exponential function, the impact of distance penalty was substantially larger for cold spots closer to the PTV centroid but petered out quickly wherever they were situated in the vicinity of PTV border. In order to evaluate the CI DD scoring system, three CT image data sets of nasopharyngeal carcinoma (NPC) patients were collected. Ten IMRT plans with degrading qualities were generated from each dataset and were ranked based on CI DD and other existing indices. The coefficient of variance was calculated for each dataset to compare the degree of variation. Results: The CI DD scoring system that considered spatial importance of each voxel within the PTV was successfully developed. The results demonstrated that the CI DD including four discrete factors could provide accurate rankings of plan quality by examining the relative

  10. Penalized likelihood fluence optimization with evolutionary components for intensity modulated radiation therapy treatment planning

    International Nuclear Information System (INIS)

    Baydush, Alan H.; Marks, Lawrence B.; Das, Shiva K.

    2004-01-01

    A novel iterative penalized likelihood algorithm with evolutionary components for the optimization of beamlet fluences for intensity modulated radiation therapy (IMRT) is presented. This algorithm is designed to be flexible in terms of the objective function and automatically escalates dose, as long as the objective function increases and all constraints are met. For this study, the objective function employed was the product of target equivalent uniform dose (EUD) and fraction of target tissue within set homogeneity constraints. The likelihood component of the algorithm iteratively attempts to minimize the mean squared error between a homogeneous dose prescription and the actual target dose distribution. The updated beamlet fluences are then adjusted via a quadratic penalty function that is based on the dose-volume histogram (DVH) constraints of the organs at risk. The evolutionary components were included to prevent the algorithm from converging to a local maximum. The algorithm was applied to a prostate cancer dataset, with especially difficult DVH constraints on bladder, rectum, and femoral heads. Dose distributions were generated for manually selected sets of three-, four-, five-, and seven-field treatment plans. Additionally, a global search was performed to find the optimal orientations for an axial three-beam plan. The results from this optimal orientation set were compared to results for manually selected orientation (gantry angle) sets of 3- (0 deg., 90 deg., 270 deg. ), 4- (0 deg., 90 deg., 180 deg., 270 deg. ), 5- (0 deg., 50 deg., 130 deg., 230 deg., 310 deg.), and 7- (0 deg., 40 deg., 90 deg., 140 deg., 230 deg., 270 deg., 320 deg. ) field axial treatment plans. For all the plans generated, all DVH constraints were met and average optimization computation time was approximately 30 seconds. For the manually selected orientations, the algorithm was successful in providing a relatively homogeneous target dose distribution, while simultaneously satisfying

  11. Optimal sensitometric curves of Kodak EDR2 film for dynamic intensity modulated radiation therapy verification.

    Science.gov (United States)

    Suriyapee, S; Pitaxtarnin, N; Oonsiri, S; Jumpangern, C; Israngkul Na Ayuthaya, I

    2008-01-01

    To investigate the optimal sensitometric curves of extended dose range (EDR2) radiographic film in terms of depth, field size, dose range and processing conditions for dynamic intensity modulated radiation therapy (IMRT) dosimetry verification with 6 MV X-ray beams. A Varian Clinac 23 EX linear accelerator with 6 MV X-ray beam was used to study the response of Kodak EDR2 film. Measurements were performed at depths of 5, 10 and 15 cm in MedTec virtual water phantom and with field sizes of 2x2, 3x3, 10x10 and 15x15 cm(2). Doses ranging from 20 to 450 cGy were used. The film was developed with the Kodak RP X-OMAT Model M6B automatic film processor. Film response was measured with the Vidar model VXR-16 scanner. Sensitometric curves were applied to the dose profiles measured with film at 5 cm in the virtual water phantom with field sizes of 2x2 and 10x10 cm(2) and compared with ion chamber data. Scanditronix/Wellhofer OmniPro(TM) IMRT software was used for the evaluation of the IMRT plan calculated by Eclipse treatment planning. Investigation of the reproducibility and accuracy of the film responses, which depend mainly on the film processor, was carried out by irradiating one film nine times with doses of 20 to 450 cGy. A maximum standard deviation of 4.9% was found which decreased to 1.9% for doses between 20 and 200 cGy. The sensitometric curves for various field sizes at fixed depth showed a maximum difference of 4.2% between 2x2 and 15x15 cm(2) at 5 cm depth with a dose of 450 cGy. The shallow depth tended to show a greater effect of field size responses than the deeper depths. The sensitometric curves for various depths at fixed field size showed slightly different film responses; the difference due to depth was within 1.8% for all field sizes studied. Both field size and depth effect were reduced when the doses were lower than 450 cGy. The difference was within 2.5% in the dose range from 20 to 300 cGy for all field sizes and depths studied. Dose profiles

  12. A novel conformity index for intensity modulated radiation therapy plan evaluation.

    Science.gov (United States)

    Cheung, Fion W K; Law, Maria Y Y

    2012-09-01

    Intensity modulated radiation therapy (IMRT) has gained popularity in the treatment of cancers. Manual evaluation of IMRT plans for head-and-neck cancers has been especially challenging necessitating efficient and objective assessment tools. In this work, the authors address this issue by developing a personalized conformity index (CI) for comparison of IMRT plans for head-and-neck cancers and evaluating its plan quality discerning power in comparison with other widely used CIs. A two-dimensional CI with dose and distance incorporated (CI(DD)) was developed using the MATLAB program language, to quantify the planning target volume (PTV) coverage. Valuable information contained in the digital imaging and communication in medicine (DICOM) RT objects were harvested for computation of each of the CI(DD) components. Apart from the dose penalty factor, a distance-based exponential function was employed by varying the penalty weight associated with the location of cold spots within the PTV. With the goal of deriving a customized penalty factor, the distances between individual pixel and its nearest PTV boundary was found. Using the exponential function, the impact of distance penalty was substantially larger for cold spots closer to the PTV centroid but petered out quickly wherever they were situated in the vicinity of PTV border. In order to evaluate the CI(DD) scoring system, three CT image data sets of nasopharyngeal carcinoma (NPC) patients were collected. Ten IMRT plans with degrading qualities were generated from each dataset and were ranked based on CI(DD) and other existing indices. The coefficient of variance was calculated for each dataset to compare the degree of variation. The CI(DD) scoring system that considered spatial importance of each voxel within the PTV was successfully developed. The results demonstrated that the CI(DD) including four discrete factors could provide accurate rankings of plan quality by examining the relative importance of each cold spot

  13. Potential Benefits of Scanned Intensity-Modulated Proton Therapy Versus Advanced Photon Therapy With Regard to Sparing of the Salivary Glands in Oropharyngeal Cancer

    International Nuclear Information System (INIS)

    Water, Tara A. van de; Lomax, Antony J.; Bijl, Hendrik P.; Jong, Marije E. de; Schilstra, Cornelis; Hug, Eugen B.; Langendijk, Johannes A.

    2011-01-01

    Purpose: To test the hypothesis that scanned intensity-modulated proton therapy (IMPT) results in a significant dose reduction to the parotid and submandibular glands as compared with intensity-modulated radiotherapy with photons (IMRT) and three-dimensional conformal radiotherapy (3D-CRT) for oropharyngeal cancer. In addition, we investigated whether the achieved dose reductions would theoretically translate into a reduction of salivary dysfunction and xerostomia. Methods and Materials: Ten patients with N0 oropharyngeal carcinoma were used. The intensity-modulated plans delivered simultaneously 70 Gy to the boost planning target volume (PTV2) and 54 Gy to the elective nodal areas (PTV1). The 3D-CRT technique delivered sequentially 70 Gy and 46 Gy to PTV2 and PTV1, respectively. Normal tissue complication probabilities were calculated for salivary dysfunction and xerostomia. Results: Planning target volume coverage results were similar for IMPT and IMRT. Intensity-modulated proton therapy clearly improved the conformity. The 3D-CRT results were inferior to these results. The mean dose to the parotid glands by 3D-CRT (50.8 Gy), IMRT (25.5 Gy), and IMPT (16.8 Gy) differed significantly. For the submandibular glands no significant differences between IMRT and IMPT were found. The dose reductions obtained with IMPT theoretically translated into a significant reduction in normal tissue complication probability. Conclusion: Compared with IMRT and 3D-CRT, IMPT improved sparing of the organs at risk, while keeping similar target coverage results. The dose reductions obtained with IMPT vs. IMRT and 3D-CRT varied widely per individual patient. Intensity-modulated proton therapy theoretically translated into a clinical benefit for most cases, but this requires clinical validation.

  14. Minimizing the number of segments in a delivery sequence for intensity-modulated radiation therapy with a multileaf collimator

    International Nuclear Information System (INIS)

    Dai Jianrong; Zhu Yunping

    2001-01-01

    This paper proposes a sequencing algorithm for intensity-modulated radiation therapy with a multileaf collimator in the static mode. The algorithm aims to minimize the number of segments in a delivery sequence. For a machine with a long verification and recording overhead time (e.g., 15 s per segment), minimizing the number of segments is equivalent to minimizing the delivery time. The proposed new algorithm is based on checking numerous candidates for a segment and selecting the candidate that results in a residual intensity matrix with the least complexity. When there is more than one candidate resulting in the same complexity, the candidate with the largest size is selected. The complexity of an intensity matrix is measured in the new algorithm in terms of the number of segments in the delivery sequence obtained by using a published algorithm. The beam delivery efficiency of the proposed algorithm and the influence of different published algorithms used to calculate the complexity of an intensity matrix were tested with clinical intensity-modulated beams. The results show that no matter which published algorithm is used to calculate the complexity of an intensity matrix, the sequence generated by the algorithm proposed here is always more efficient than that generated by the published algorithm itself. The results also show that the algorithm used to calculate the complexity of an intensity matrix affects the efficiency of beam delivery. The delivery sequences are frequently most efficient when the algorithm of Bortfeld et al. is used to calculate the complexity of an intensity matrix. Because no single variation is most efficient for all beams tested, we suggest implementing multiple variations of our algorithm

  15. Comparison of acute and subacute genitourinary and gastrointestinal adverse events of radiotherapy for prostate cancer using intensity-modulated radiation therapy, three-dimensional conformal radiation therapy, permanent implant brachytherapy and high-dose-rate brachytherapy

    NARCIS (Netherlands)

    Morimoto, Masahiro; Yoshioka, Yasuo; Konishi, Koji; Isohashi, Fumiaki; Takahashi, Yutaka; Ogata, Toshiyuki; Koizumi, Masahiko; Teshima, Teruki; Bijl, Henk P; van der Schaaf, Arjen; Langendijk, Johannes A; Ogawa, Kazuhiko

    2014-01-01

    AIMS AND BACKGROUND: To examine acute and subacute urinary and rectal toxicity in patients with localized prostate cancer monotherapeutically treated with the following four radiotherapeutic techniques: intensity-modulated radiation therapy, three-dimensional conformal radiation therapy,

  16. Automated Volumetric Modulated Arc Therapy Treatment Planning for Stage III Lung Cancer: How Does It Compare With Intensity-Modulated Radio Therapy?

    Energy Technology Data Exchange (ETDEWEB)

    Quan, Enzhuo M. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chang, Joe Y.; Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Xia Tingyi [Department of Radiation Oncology, Beijing 301 Hospital, Beijing (China); Yuan Zhiyong [Department of Radiation Oncology, Tianjin Medical University Cancer Hospital and Institute, Tianjin (China); Liu Hui [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, Zhongshan University Hospital, Guangzhou (China); Li, Xiaoqiang; Wages, Cody A.; Mohan, Radhe [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Zhang Xiaodong, E-mail: xizhang@mdanderson.org [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2012-09-01

    Purpose: To compare the quality of volumetric modulated arc therapy (VMAT) or intensity-modulated radiation therapy (IMRT) plans generated by an automated inverse planning system with that of dosimetrist-generated IMRT treatment plans for patients with stage III lung cancer. Methods and Materials: Two groups of 8 patients with stage III lung cancer were randomly selected. For group 1, the dosimetrists spent their best effort in designing IMRT plans to compete with the automated inverse planning system (mdaccAutoPlan); for group 2, the dosimetrists were not in competition and spent their regular effort. Five experienced radiation oncologists independently blind-reviewed and ranked the three plans for each patient: a rank of 1 was the best and 3 was the worst. Dosimetric measures were also performed to quantitatively evaluate the three types of plans. Results: Blind rankings from different oncologists were generally consistent. For group 1, the auto-VMAT, auto-IMRT, and manual IMRT plans received average ranks of 1.6, 2.13, and 2.18, respectively. The auto-VMAT plans in group 1 had 10% higher planning tumor volume (PTV) conformality and 24% lower esophagus V70 (the volume receiving 70 Gy or more) than the manual IMRT plans; they also resulted in more than 20% higher complication-free tumor control probability (P+) than either type of IMRT plans. The auto- and manual IMRT plans in this group yielded generally comparable dosimetric measures. For group 2, the auto-VMAT, auto-IMRT, and manual IMRT plans received average ranks of 1.55, 1.75, and 2.75, respectively. Compared to the manual IMRT plans in this group, the auto-VMAT plans and auto-IMRT plans showed, respectively, 17% and 14% higher PTV dose conformality, 8% and 17% lower mean lung dose, 17% and 26% lower mean heart dose, and 36% and 23% higher P+. Conclusions: mdaccAutoPlan is capable of generating high-quality VMAT and IMRT treatment plans for stage III lung cancer. Manual IMRT plans could achieve quality

  17. Automated Volumetric Modulated Arc Therapy Treatment Planning for Stage III Lung Cancer: How Does It Compare With Intensity-Modulated Radio Therapy?

    International Nuclear Information System (INIS)

    Quan, Enzhuo M.; Chang, Joe Y.; Liao Zhongxing; Xia Tingyi; Yuan Zhiyong; Liu Hui; Li, Xiaoqiang; Wages, Cody A.; Mohan, Radhe; Zhang Xiaodong

    2012-01-01

    Purpose: To compare the quality of volumetric modulated arc therapy (VMAT) or intensity-modulated radiation therapy (IMRT) plans generated by an automated inverse planning system with that of dosimetrist-generated IMRT treatment plans for patients with stage III lung cancer. Methods and Materials: Two groups of 8 patients with stage III lung cancer were randomly selected. For group 1, the dosimetrists spent their best effort in designing IMRT plans to compete with the automated inverse planning system (mdaccAutoPlan); for group 2, the dosimetrists were not in competition and spent their regular effort. Five experienced radiation oncologists independently blind-reviewed and ranked the three plans for each patient: a rank of 1 was the best and 3 was the worst. Dosimetric measures were also performed to quantitatively evaluate the three types of plans. Results: Blind rankings from different oncologists were generally consistent. For group 1, the auto-VMAT, auto-IMRT, and manual IMRT plans received average ranks of 1.6, 2.13, and 2.18, respectively. The auto-VMAT plans in group 1 had 10% higher planning tumor volume (PTV) conformality and 24% lower esophagus V70 (the volume receiving 70 Gy or more) than the manual IMRT plans; they also resulted in more than 20% higher complication-free tumor control probability (P+) than either type of IMRT plans. The auto- and manual IMRT plans in this group yielded generally comparable dosimetric measures. For group 2, the auto-VMAT, auto-IMRT, and manual IMRT plans received average ranks of 1.55, 1.75, and 2.75, respectively. Compared to the manual IMRT plans in this group, the auto-VMAT plans and auto-IMRT plans showed, respectively, 17% and 14% higher PTV dose conformality, 8% and 17% lower mean lung dose, 17% and 26% lower mean heart dose, and 36% and 23% higher P+. Conclusions: mdaccAutoPlan is capable of generating high-quality VMAT and IMRT treatment plans for stage III lung cancer. Manual IMRT plans could achieve quality

  18. Intensity-modulated proton therapy, volumetric-modulated arc therapy, and 3D conformal radiotherapy in anaplastic astrocytoma and glioblastoma. A dosimetric comparison

    Energy Technology Data Exchange (ETDEWEB)

    Adeberg, S.; Debus, J. [Heidelberg Institute of Radiation Oncology (HIRO), Heidelberg (Germany); Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg (Germany); University Hospital Heidelberg, Department of Radiation Oncology, Heidelberg (Germany); German Cancer Research Center (DKFZ), Clinical Cooperation Unit Radiation Oncology, Heidelberg (Germany); Harrabi, S.B.; Bougatf, N.; Rieber, J.; Koerber, S.A.; Herfarth, K.; Rieken, S. [Heidelberg Institute of Radiation Oncology (HIRO), Heidelberg (Germany); Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg (Germany); University Hospital Heidelberg, Department of Radiation Oncology, Heidelberg (Germany); Bernhardt, D.; Syed, M.; Sprave, T.; Mohr, A. [Heidelberg Institute of Radiation Oncology (HIRO), Heidelberg (Germany); University Hospital Heidelberg, Department of Radiation Oncology, Heidelberg (Germany); Abdollahi, A. [University Hospital Heidelberg, Department of Radiation Oncology, Heidelberg (Germany); Haberer, T. [Heidelberg Institute of Radiation Oncology (HIRO), Heidelberg (Germany); Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg (Germany); Combs, S.E. [Technische Universitaet Muenchen, Department of Radiation Oncology, Muenchen (Germany); Helmholtz Zentrum Muenchen, Institut fuer Innovative Radiotherapie (iRT), Department of Radiation Sciences (DRS), Neuherberg (Germany)

    2016-11-15

    The prognosis for high-grade glioma (HGG) patients is poor; thus, treatment-related side effects need to be minimized to conserve quality of life and functionality. Advanced techniques such as proton radiation therapy (PRT) and volumetric-modulated arc therapy (VMAT) may potentially further reduce the frequency and severity of radiogenic impairment. We retrospectively assessed 12 HGG patients who had undergone postoperative intensity-modulated proton therapy (IMPT). VMAT and 3D conformal radiotherapy (3D-CRT) plans were generated and optimized for comparison after contouring crucial neuronal structures important for neurogenesis and neurocognitive function. Integral dose (ID), homogeneity index (HI), and inhomogeneity coefficient (IC) were calculated from dose statistics. Toxicity data were evaluated. Target volume coverage was comparable for all three modalities. Compared to 3D-CRT and VMAT, PRT showed statistically significant reductions (p < 0.05) in mean dose to whole brain (-20.2 %, -22.7 %); supratentorial (-14.2 %, -20,8 %) and infratentorial (-91.0 %, -77.0 %) regions; brainstem (-67.6 %, -28.1 %); pituitary gland (-52.9 %, -52.5 %); contralateral hippocampus (-98.9 %, -98.7 %); and contralateral subventricular zone (-62.7 %, -66.7 %, respectively). Fatigue (91.7 %), radiation dermatitis (75.0 %), focal alopecia (100.0 %), nausea (41.7 %), cephalgia (58.3 %), and transient cerebral edema (16.7 %) were the most common acute toxicities. Essential dose reduction while maintaining equal target volume coverage was observed using PRT, particularly in contralaterally located critical neuronal structures, areas of neurogenesis, and structures of neurocognitive functions. These findings were supported by preliminary clinical results confirming the safety and feasibility of PRT in HGG. (orig.) [German] Die Prognose bei ''High-grade''-Gliomen (HGG) ist infaust. Gerade bei diesen Patienten sollten therapieassoziierte Nebenwirkungen minimiert werden

  19. Bone marrow sparing in intensity modulated proton therapy for cervical cancer: Efficacy and robustness under range and setup uncertainties

    International Nuclear Information System (INIS)

    Dinges, Eric; Felderman, Nicole; McGuire, Sarah; Gross, Brandie; Bhatia, Sudershan; Mott, Sarah; Buatti, John; Wang, Dongxu

    2015-01-01

    Background and purpose: This study evaluates the potential efficacy and robustness of functional bone marrow sparing (BMS) using intensity-modulated proton therapy (IMPT) for cervical cancer, with the goal of reducing hematologic toxicity. Material and methods: IMPT plans with prescription dose of 45 Gy were generated for ten patients who have received BMS intensity-modulated X-ray therapy (IMRT). Functional bone marrow was identified by 18 F-flourothymidine positron emission tomography. IMPT plans were designed to minimize the volume of functional bone marrow receiving 5–40 Gy while maintaining similar target coverage and healthy organ sparing as IMRT. IMPT robustness was analyzed with ±3% range uncertainty errors and/or ±3 mm translational setup errors in all three principal dimensions. Results: In the static scenario, the median dose volume reductions for functional bone marrow by IMPT were: 32% for V 5Gy , 47% for V 10Gy , 54% for V 20Gy , and 57% for V 40Gy , all with p < 0.01 compared to IMRT. With assumed errors, even the worst-case reductions by IMPT were: 23% for V 5Gy , 37% for V 10Gy , 41% for V 20Gy , and 39% for V 40Gy , all with p < 0.01. Conclusions: The potential sparing of functional bone marrow by IMPT for cervical cancer is significant and robust under realistic systematic range uncertainties and clinically relevant setup errors

  20. Bone Marrow Sparing in Intensity Modulated Proton Therapy for Cervical Cancer: Efficacy and Robustness under Range and Setup Uncertainties

    Science.gov (United States)

    Dinges, Eric; Felderman, Nicole; McGuire, Sarah; Gross, Brandie; Bhatia, Sudershan; Mott, Sarah; Buatti, John; Wang, Dongxu

    2015-01-01

    Background and Purpose This study evaluates the potential efficacy and robustness of functional bone marrow sparing (BMS) using intensity-modulated proton therapy (IMPT) for cervical cancer, with the goal of reducing hematologic toxicity. Material and Methods IMPT plans with prescription dose of 45 Gy were generated for ten patients who have received BMS intensity-modulated x-ray therapy (IMRT). Functional bone marrow was identified by 18F-flourothymidine positron emission tomography. IMPT plans were designed to minimize the volume of functional bone marrow receiving 5–40 Gy while maintaining similar target coverage and healthy organ sparing as IMRT. IMPT robustness was analyzed with ±3% range uncertainty errors and/or ±3mm translational setup errors in all three principal dimensions. Results In the static scenario, the median dose volume reductions for functional bone marrow by IMPT were: 32% for V5GY, 47% for V10Gy, 54% for V20Gy, and 57% for V40Gy, all with p<0.01 compared to IMRT. With assumed errors, even the worst-case reductions by IMPT were: 23% for V5Gy, 37% for V10Gy, 41% for V20Gy, and 39% for V40Gy, all with p<0.01. Conclusions The potential sparing of functional bone marrow by IMPT for cervical cancer is significant and robust under realistic systematic range uncertainties and clinically relevant setup errors. PMID:25981130

  1. Target volume delineation and field setup. A practical guide for conformal and intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Nancy Y. [Memorial Sloan-Kettering Cancer Center, New York, NY (United States). Radiation Oncology; Lu, Jiade J. (eds.) [National Univ. Health System, Singapore (Singapore). Dept. of Radiation Oncology; National Univ. of Singapore (Singapore). Dept. of Medicine

    2013-03-01

    Practical handbook on selection and delineation of tumor volumes and fields for conformal radiation therapy, including IMRT. Helpful format facilitating use on a step-by-step basis in daily practice. Designed to ensure accurate coverage of commonly encountered tumors along their routes of spread. This handbook is designed to enable radiation oncologists to appropriately and confidently delineate tumor volumes/fields for conformal radiation therapy, including intensity-modulated radiation therapy (IMRT), in patients with commonly encountered cancers. The orientation of this handbook is entirely practical, in that the focus is on the illustration of clinical target volume (CTV) delineation for each major malignancy. Each chapter provides guidelines and concise knowledge on CTV selection for a particular disease, explains how the anatomy of lymphatic drainage shapes the selection of the target volume, and presents detailed illustrations of volumes, slice by slice, on planning CT images. While the emphasis is on target volume delineation for three-dimensional conformal therapy and IMRT, information is also provided on conventional radiation therapy field setup and planning for certain malignancies for which IMRT is not currently suitable.

  2. A new Monte Carlo-based treatment plan optimization approach for intensity modulated radiation therapy.

    Science.gov (United States)

    Li, Yongbao; Tian, Zhen; Shi, Feng; Song, Ting; Wu, Zhaoxia; Liu, Yaqiang; Jiang, Steve; Jia, Xun

    2015-04-07

    Intensity-modulated radiation treatment (IMRT) plan optimization needs beamlet dose distributions. Pencil-beam or superposition/convolution type algorithms are typically used because of their high computational speed. However, inaccurate beamlet dose distributions may mislead the optimization process and hinder the resulting plan quality. To solve this problem, the Monte Carlo (MC) simulation method has been used to compute all beamlet doses prior to the optimization step. The conventional approach samples the same number of particles from each beamlet. Yet this is not the optimal use of MC in this problem. In fact, there are beamlets that have very small intensities after solving the plan optimization problem. For those beamlets, it may be possible to use fewer particles in dose calculations to increase efficiency. Based on this idea, we have developed a new MC-based IMRT plan optimization framework that iteratively performs MC dose calculation and plan optimization. At each dose calculation step, the particle numbers for beamlets were adjusted based on the beamlet intensities obtained through solving the plan optimization problem in the last iteration step. We modified a GPU-based MC dose engine to allow simultaneous computations of a large number of beamlet doses. To test the accuracy of our modified dose engine, we compared the dose from a broad beam and the summed beamlet doses in this beam in an inhomogeneous phantom. Agreement within 1% for the maximum difference and 0.55% for the average difference was observed. We then validated the proposed MC-based optimization schemes in one lung IMRT case. It was found that the conventional scheme required 10(6) particles from each beamlet to achieve an optimization result that was 3% difference in fluence map and 1% difference in dose from the ground truth. In contrast, the proposed scheme achieved the same level of accuracy with on average 1.2 × 10(5) particles per beamlet. Correspondingly, the computation

  3. Inverse treatment planning for intensity modulated radiation therapy: CDVH treatment prescription with integral cost function

    International Nuclear Information System (INIS)

    Carol, M.P.; Nash, R.; Campbell, R.C.; Huber, R.

    1997-01-01

    Purpose/Objective: Inverse planning is a required approach when dealing with the complexity of variables present in an intensity modulated plan. However, an inverse planning system is only as useful as it is 1) easy to use and 2) predictable in its result. This is especially the case when the target goals and structure limits specified by the user all cannot be achieved. We have previously developed two interfaces for specifying how such conflicts should be resolved when they occur, that, although allowing a range of results to be obtained, still require 'trial and error' on the part of the user and are case dependent. A new method is explored with goals of allowing the desired results to be specified in an intuitive manner and producing predictable results that are case independent. Materials and Methods: Target goals and structure limits are specified by entering partial volume data: goal/limit, % under/over goal/limit, minimum, maximum. This data is converted to a CDVH curve for each target/structure. During the simulated annealing process used to produce an optimized solution, the actual CDVHs are compared to the desired CDVHs after each iteration and a cost is computed for the difference between the curves. For each curve, the cost is proportional to the difference in area between the desired and actual curves. This cost is controlled by three variables: offset (amount of difference before there is any cost), scale (the range the cost can take) and shape (the shape of the curve for difference versus cost). A range of values were explored for these variables in order to determine if predictable trade-offs would be made automatically by the system. The cost function was tested against a range of cases: a highly irregularly shaped intracranial lesion, a head and neck case with three target volumes with different prescriptions, and a prostate cancer. Results: By varying the values assigned to the control variables, a variety of predictable results could be

  4. Immobilization and positioning systems for treatment of patients with image-guided radiation therapy and intensity modulated radiation therapy)

    International Nuclear Information System (INIS)

    Hueso Bernad, M. Nuria; Suarez Dieguez, Raquel; Roures Ramos, M. Teresa; Broseta Tormos, M.Mercedes; Tirado Porcar, Miriam M; Del Castillo Arres, Jose; Franch Martinez, Silvia

    2009-01-01

    For adequate reproduction of daily patient positioning during treatment we use a 3-coordinate system alignment. The first set of axes would be the system of light (laser). - The second coordinate system is recognized by marks on the skin patient and / or immobilization systems. The third set of alignment refers to alignment of coordinates volume to try to locate the isocenter use Guided Radiotherapy Imaging when applied technologies with Intensity Modulated Radiotherapy treatment fields tend to be very small so it made individual protection and immobilization systems such as thermoplastic masks, vacuum sealed bags exterotaxicos conjugated systems and immobilization systems carbon fiber results by combining these immobilization and positioning systems can ensure effective treatment volume to be treated. There is no perfect immobilization system. However the choice of pool of qualified stun makes treatment more precise. (author)

  5. Radiation efficacy and biological risk from whole-breast irradiation via intensity modulated radiation therapy (IMRT)

    Science.gov (United States)

    Desantis, David M.

    Radiotherapy is an established modality for women with breast cancer. During the delivery of external beam radiation to the breast, leakage, scattered x-rays from the patient and the linear accelerator also expose healthy tissues and organs outside of the breast, thereby increasing the patient's whole-body dose, which then increases the chance of developing a secondary, radiation-induced cancer. Generally, there are three IntensityModulated Radiotherapy (IMRT) delivery techniques from a conventional linear accelerator; forward planned (FMLC), inverse planned 'sliding window' (DMLC), and inverse planned 'step-and-shoot' (SMLC). The goal of this study was to determine which of these three techniques delivers an optimal dose to the breast with the least chance of causing a fatal, secondary, radiation-induced cancer. A conventional, non-IMRT, 'Wedge' plan also was compared. Computerized Tomography (CT) data sets for both a large and small sized patient were used in this study. With Varian's Eclipse AAA algorithm, the organ doses specified in the revised ICRP 60 publication were used to calculate the whole-body dose. Also, an anthropomorphic phantom was irradiated with thermoluminescent dosimeters (TLD) at each organ site for measured doses. The risk coefficient from the Biological Effects of Ionizing Radiation (BEIR) VII report of 4.69 x 10-2 deaths per Gy was used to convert whole-body dose to risk of a fatal, secondary, radiation-induced cancer. The FMLC IMRT delivered superior tumor coverage over the 3D conventional plan and the inverse DMLC or SMLC treatment plans delivered clinically equivalent tumor coverage. However, the FMLC plan had the least likelihood of inadvertently causing a fatal, secondary, radiation-induced cancer compared to the inverse DMLC, SMLC, and Wedge plans.

  6. CT image-guided intensity-modulated therapy for paraspinal tumors using stereotactic immobilization

    International Nuclear Information System (INIS)

    Yenice, Kamil M.; Lovelock, D. Michael; Hunt, Margie A.; Lutz, Wendell R.; Fournier-Bidoz, Nathalie; Hua, C.-H.; Yamada, Josh; Bilsky, Mark; Lee, Henry; Pfaff, Karl; Spirou, Spiridon V.; Amols, Howard I.

    2003-01-01

    Purpose: To design and implement a noninvasive stereotactic immobilization technique with daily CT image-guided positioning to treat patients with paraspinal lesions accurately and to quantify the systematic and random patient setup errors occurring with this method. Methods and Materials: A stereotactic body frame (SBF) was developed for 'rigid' immobilization of paraspinal patients. The inherent accuracy of this system for stereotactic CT-guided treatment was evaluated with phantom studies. Seven patients with thoracic and lumbar spine lesions were immobilized with the SBF and positioned for 33 treatment fractions using daily CT scans. For all 7 patients, the daily setup errors, as assessed from the daily CT scans, were corrected at each treatment fraction. A retrospective analysis was also performed to assess what the impact on patient treatment would have been without the CT-based corrections (i.e., if patient setup had been performed only with the SBF). Results: The average magnitude of systematic and random errors from uncorrected patient setups using the SBF was approximately 2 mm and 1.5 mm (1 SD), respectively. For fixed phantom targets, the system accuracy for the SBF localization and treatment was shown to be within 1 mm (1 SD) in any direction. Dose-volume histograms incorporating these uncertainties for an intensity-modulated radiotherapy plan for lumbar spine lesions were generated, and the effects on the dose-volume histograms were studied. Conclusion: We demonstrated a very accurate and precise method of patient immobilization and treatment delivery based on a noninvasive SBF and daily image guidance for paraspinal lesions. The SBF provides excellent immobilization for paraspinal targets, with setup accuracy better than 2 mm (1 SD). However, for highly conformal paraspinal treatments, uncorrected systematic and random errors of 2 mm in magnitude can result in a significantly greater (>100%) dose to the spinal cord than planned, even though the

  7. A fast algorithm for solving a linear feasibility problem with application to Intensity-Modulated Radiation Therapy.

    Science.gov (United States)

    Herman, Gabor T; Chen, Wei

    2008-03-01

    The goal of Intensity-Modulated Radiation Therapy (IMRT) is to deliver sufficient doses to tumors to kill them, but without causing irreparable damage to critical organs. This requirement can be formulated as a linear feasibility problem. The sequential (i.e., iteratively treating the constraints one after another in a cyclic fashion) algorithm ART3 is known to find a solution to such problems in a finite number of steps, provided that the feasible region is full dimensional. We present a faster algorithm called ART3+. The idea of ART3+ is to avoid unnecessary checks on constraints that are likely to be satisfied. The superior performance of the new algorithm is demonstrated by mathematical experiments inspired by the IMRT application.

  8. The integration of DVH-based planning aspects into a convex intensity modulated radiation therapy optimization framework

    Energy Technology Data Exchange (ETDEWEB)

    Kratt, Karin [Faculty of Mathematics, Technical University of Kaiserslautern, Kaiserslautern (Germany); Scherrer, Alexander [Department of Optimization, Fraunhofer Institute for Industrial Mathematics (ITWM), Kaiserslautern (Germany)], E-mail: alexander.scherrer@itwm.fraunhofer.de

    2009-06-21

    The formulation of intensity modulated radiation therapy (IMRT) planning aspects frequently uses the dose-volume histogram (DVH), whereas plan computations often happen in the more desirable convex IMRT optimization framework. Inspired by a recent publication of Zinchenko et al (2008 Phys. Med. Biol. 53 3231-50), this work addresses the integration of DVH-based planning aspects into this framework from a general point of view. It first provides the basic mathematical requirements on the evaluation functions in order to support such an incorporation. Then it introduces the condition number as a description for how precisely DVH-based planning aspects can be reformulated in terms of evaluation functions. Exemplary numerical studies for the generalized equivalent uniform dose and a physical constraint function show the influence of function parameter values and DVH approximation on the condition number. The work concludes by formulating the aspects that should be taken into account for an appropriate integration of DVH-based planning aspects. (note)

  9. The impact of leaf width and plan complexity on DMLC tracking of prostate intensity modulated arc therapy

    DEFF Research Database (Denmark)

    Pommer, Tobias; Falk, Marianne; Poulsen, Per Rugaard

    2013-01-01

    Purpose: Intensity modulated arc therapy (IMAT) is commonly used to treat prostate cancer. The purpose of this study was to evaluate the impact of leaf width and plan complexity on dynamic multileaf collimator (DMLC) tracking for prostate motion management during IMAT treatments.Methods: Prostate...... IMAT plans were delivered with either a high-definition MLC (HDMLC) or a Millennium MLC (M-MLC) (0.25 and 0.50 cm central leaf width, respectively), with and without DMLC tracking, to a dosimetric phantom that reproduced four prostate motion traces. The plan complexity was varied by applying leaf....... The corresponding pass rates without tracking were 87.6% (range 76.2%-94.7%) and 91.1% (range 81.4%-97.6%), respectively. Decreased plan complexity improved the pass rate when static target measurements were used as reference, but not with the planned dose as reference. The main cause of tracking errors was leaf...

  10. Discussion of feasibility to carry out intensity modulated radiation therapy in conventional medical electron linear accelerator treatment rooms

    International Nuclear Information System (INIS)

    Yang Haiyou; Liu Liping; Liang Yueqin; Zhang Liang; Yu Shui

    2010-01-01

    Objective: To investigate the feasibility about the shielding effect of conventional medical electron linear accelerator treatment in the existing rooms to carry out intensity modulated radiation therapy (IMRT). Methods: The estimation model given in NCRP REPORT No. 151- S tructural Shielding Design and Evaluation for Megavoltage X-and Gamma-Ray Radiotherapy Facilities i s adopted by linking instances, which presents the calculation methods on radiation level at the ambience of megavoltage medical electron linear accelerator treatment room. Results: The radiation level, as well as the additional annual effect dose of occupational and public at the ambience of accelerator treatment room, in crease to a certain extent, when conventional medical electron linear accelerator treatment room; are used to carry out IMRT. Conclusion: It is necessary to make environmental impact assessment for conventional medical electron linear accelerator treatment rooms, which will be used to execute IMRT. (authors)

  11. The integration of DVH-based planning aspects into a convex intensity modulated radiation therapy optimization framework

    International Nuclear Information System (INIS)

    Kratt, Karin; Scherrer, Alexander

    2009-01-01

    The formulation of intensity modulated radiation therapy (IMRT) planning aspects frequently uses the dose-volume histogram (DVH), whereas plan computations often happen in the more desirable convex IMRT optimization framework. Inspired by a recent publication of Zinchenko et al (2008 Phys. Med. Biol. 53 3231-50), this work addresses the integration of DVH-based planning aspects into this framework from a general point of view. It first provides the basic mathematical requirements on the evaluation functions in order to support such an incorporation. Then it introduces the condition number as a description for how precisely DVH-based planning aspects can be reformulated in terms of evaluation functions. Exemplary numerical studies for the generalized equivalent uniform dose and a physical constraint function show the influence of function parameter values and DVH approximation on the condition number. The work concludes by formulating the aspects that should be taken into account for an appropriate integration of DVH-based planning aspects. (note)

  12. A Phase 1 Study of Everolimus + Weekly Cisplatin + Intensity Modulated Radiation Therapy in Head-and-Neck Cancer

    International Nuclear Information System (INIS)

    Fury, Matthew G.; Lee, Nancy Y.; Sherman, Eric; Ho, Alan L.; Rao, Shyam; Heguy, Adriana; Shen, Ronglai; Korte, Susan; Lisa, Donna; Ganly, Ian; Patel, Snehal; Wong, Richard J.; Shaha, Ashok; Shah, Jatin; Haque, Sofia; Katabi, Nora; Pfister, David G.

    2013-01-01

    Purpose: Elevated expression of eukaryotic protein synthesis initiation factor 4E (eIF4E) in histologically cancer-free margins of resected head and neck squamous cell carcinomas (HNSCCs) is mediated by mammalian target of rapamycin complex 1 (mTORC1) and has been associated with increased risk of disease recurrence. Preclinically, inhibition of mTORC1 with everolimus sensitizes cancer cells to cisplatin and radiation. Methods and Materials: This was single-institution phase 1 study to establish the maximum tolerated dose of daily everolimus given with fixed dose cisplatin (30 mg/m 2 weekly × 6) and concurrent intensity modulated radiation therapy for patients with locally and/or regionally advanced head-and-neck cancer. The study had a standard 3 + 3 dose-escalation design. Results: Tumor primary sites were oral cavity (4), salivary gland (4), oropharynx (2), nasopharynx (1), scalp (1), and neck node with occult primary (1). In 4 of 4 cases in which resected HNSCC surgical pathology specimens were available for immunohistochemistry, elevated expression of eIF4E was observed in the cancer-free margins. The most common grade ≥3 treatment-related adverse event was lymphopenia (92%), and dose-limiting toxicities (DLTs) were mucositis (n=2) and failure to thrive (n=1). With a median follow up of 19.4 months, 2 patients have experienced recurrent disease. The maximum tolerated dose was everolimus 5 mg/day. Conclusions: Head-and-neck cancer patients tolerated everolimus at therapeutic doses (5 mg/day) given with weekly cisplatin and intensity modulated radiation therapy. The regimen merits further evaluation, especially among patients who are status post resection of HNSCCs that harbor mTORC1-mediated activation of eIF4E in histologically negative surgical margins

  13. A Phase 1 Study of Everolimus + Weekly Cisplatin + Intensity Modulated Radiation Therapy in Head-and-Neck Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Fury, Matthew G. [Department of Medicine, Head and Neck Oncology Service, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Medicine, Weill Cornell Medical College, New York, New York (United States); Lee, Nancy Y. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Sherman, Eric; Ho, Alan L. [Department of Medicine, Head and Neck Oncology Service, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Medicine, Weill Cornell Medical College, New York, New York (United States); Rao, Shyam [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Heguy, Adriana [Department of Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Shen, Ronglai [Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Korte, Susan; Lisa, Donna [Department of Medicine, Head and Neck Oncology Service, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Ganly, Ian; Patel, Snehal; Wong, Richard J.; Shaha, Ashok; Shah, Jatin [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Haque, Sofia [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Katabi, Nora [Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Pfister, David G. [Department of Medicine, Head and Neck Oncology Service, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Medicine, Weill Cornell Medical College, New York, New York (United States)

    2013-11-01

    Purpose: Elevated expression of eukaryotic protein synthesis initiation factor 4E (eIF4E) in histologically cancer-free margins of resected head and neck squamous cell carcinomas (HNSCCs) is mediated by mammalian target of rapamycin complex 1 (mTORC1) and has been associated with increased risk of disease recurrence. Preclinically, inhibition of mTORC1 with everolimus sensitizes cancer cells to cisplatin and radiation. Methods and Materials: This was single-institution phase 1 study to establish the maximum tolerated dose of daily everolimus given with fixed dose cisplatin (30 mg/m{sup 2} weekly × 6) and concurrent intensity modulated radiation therapy for patients with locally and/or regionally advanced head-and-neck cancer. The study had a standard 3 + 3 dose-escalation design. Results: Tumor primary sites were oral cavity (4), salivary gland (4), oropharynx (2), nasopharynx (1), scalp (1), and neck node with occult primary (1). In 4 of 4 cases in which resected HNSCC surgical pathology specimens were available for immunohistochemistry, elevated expression of eIF4E was observed in the cancer-free margins. The most common grade ≥3 treatment-related adverse event was lymphopenia (92%), and dose-limiting toxicities (DLTs) were mucositis (n=2) and failure to thrive (n=1). With a median follow up of 19.4 months, 2 patients have experienced recurrent disease. The maximum tolerated dose was everolimus 5 mg/day. Conclusions: Head-and-neck cancer patients tolerated everolimus at therapeutic doses (5 mg/day) given with weekly cisplatin and intensity modulated radiation therapy. The regimen merits further evaluation, especially among patients who are status post resection of HNSCCs that harbor mTORC1-mediated activation of eIF4E in histologically negative surgical margins.

  14. Dosimetric comparison of different schemes for arrange beams in intensity modulated radiation therapy for mid- and distal-esophageal carcinoma

    International Nuclear Information System (INIS)

    Zhang Min; Zhou Li; Zhang Kaixian; Li Ling; Shi Cun

    2012-01-01

    Objective: To analyze the difference between five-field plan and seven-field plan in intensity modulated radiation therapy for patients with mid- and distal-esophageal carcinoma,and to find out the optimal beam arrangement. Methods: Five-field plan and seven-field plan were designed for each of 12 patients with mid- and distal-esophageal carcinoma. 95% of planning target volume was required to achieve prescription dose. Dose-volume histograms statistics, dose uniformity, and dose conformity in every patient were compared respectively.Results: Superior dose conformity for planning target volume was shown in seven-field plan (t=2.681, P<0.05). Difference was not significant between uniformity in seven-field plan and that in five-field plan. Difference was not significant between doses received by organs at risk,such as spinal cord and heart,in seven-field plan and those in five-field plan. V 5 , V 10 , V 15 of lungs in five-field plan were lower significantly than those in seven-field plan (t=-7.938, -12.055 and -4.859, all P<0.05). Conclusions: For patients with thoracic esophageal carcinoma treated by intensity modulate radiation therapy, compared with 7-fielded plan,the volume of lungs with lower dose could be reduced on the premise of acceptable planning target volume coverage by the application of five-plan. Therefore, radiation-induced lung injury occurrence probability would be reduced, and the patient's quality of life would be improved. Five-field plan would be worth applying in the clinical work. (authors)

  15. A novel software and conceptual design of the hardware platform for intensity modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Dan; Ruan, Dan; O’Connor, Daniel; Woods, Kaley; Low, Daniel A.; Sheng, Ke, E-mail: ksheng@mednet.ucla.edu [Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, California 90024 (United States); Boucher, Salime [RadiaBeam Technologies, Santa Monica, California 90404 (United States)

    2016-02-15

    Purpose: To deliver high quality intensity modulated radiotherapy (IMRT) using a novel generalized sparse orthogonal collimators (SOCs), the authors introduce a novel direct aperture optimization (DAO) approach based on discrete rectangular representation. Methods: A total of seven patients—two glioblastoma multiforme, three head & neck (including one with three prescription doses), and two lung—were included. 20 noncoplanar beams were selected using a column generation and pricing optimization method. The SOC is a generalized conventional orthogonal collimators with N leaves in each collimator bank, where N = 1, 2, or 4. SOC degenerates to conventional jaws when N = 1. For SOC-based IMRT, rectangular aperture optimization (RAO) was performed to optimize the fluence maps using rectangular representation, producing fluence maps that can be directly converted into a set of deliverable rectangular apertures. In order to optimize the dose distribution and minimize the number of apertures used, the overall objective was formulated to incorporate an L2 penalty reflecting the difference between the prescription and the projected doses, and an L1 sparsity regularization term to encourage a low number of nonzero rectangular basis coefficients. The optimization problem was solved using the Chambolle–Pock algorithm, a first-order primal–dual algorithm. Performance of RAO was compared to conventional two-step IMRT optimization including fluence map optimization and direct stratification for multileaf collimator (MLC) segmentation (DMS) using the same number of segments. For the RAO plans, segment travel time for SOC delivery was evaluated for the N = 1, N = 2, and N = 4 SOC designs to characterize the improvement in delivery efficiency as a function of N. Results: Comparable PTV dose homogeneity and coverage were observed between the RAO and the DMS plans. The RAO plans were slightly superior to the DMS plans in sparing critical structures. On average, the maximum and

  16. A novel software and conceptual design of the hardware platform for intensity modulated radiation therapy.

    Science.gov (United States)

    Nguyen, Dan; Ruan, Dan; O'Connor, Daniel; Woods, Kaley; Low, Daniel A; Boucher, Salime; Sheng, Ke

    2016-02-01

    To deliver high quality intensity modulated radiotherapy (IMRT) using a novel generalized sparse orthogonal collimators (SOCs), the authors introduce a novel direct aperture optimization (DAO) approach based on discrete rectangular representation. A total of seven patients-two glioblastoma multiforme, three head & neck (including one with three prescription doses), and two lung-were included. 20 noncoplanar beams were selected using a column generation and pricing optimization method. The SOC is a generalized conventional orthogonal collimators with N leaves in each collimator bank, where N = 1, 2, or 4. SOC degenerates to conventional jaws when N = 1. For SOC-based IMRT, rectangular aperture optimization (RAO) was performed to optimize the fluence maps using rectangular representation, producing fluence maps that can be directly converted into a set of deliverable rectangular apertures. In order to optimize the dose distribution and minimize the number of apertures used, the overall objective was formulated to incorporate an L2 penalty reflecting the difference between the prescription and the projected doses, and an L1 sparsity regularization term to encourage a low number of nonzero rectangular basis coefficients. The optimization problem was solved using the Chambolle-Pock algorithm, a first-order primal-dual algorithm. Performance of RAO was compared to conventional two-step IMRT optimization including fluence map optimization and direct stratification for multileaf collimator (MLC) segmentation (DMS) using the same number of segments. For the RAO plans, segment travel time for SOC delivery was evaluated for the N = 1, N = 2, and N = 4 SOC designs to characterize the improvement in delivery efficiency as a function of N. Comparable PTV dose homogeneity and coverage were observed between the RAO and the DMS plans. The RAO plans were slightly superior to the DMS plans in sparing critical structures. On average, the maximum and mean critical organ doses were

  17. Full Monte Carlo-Based Biologic Treatment Plan Optimization System for Intensity Modulated Carbon Ion Therapy on Graphics Processing Unit.

    Science.gov (United States)

    Qin, Nan; Shen, Chenyang; Tsai, Min-Yu; Pinto, Marco; Tian, Zhen; Dedes, Georgios; Pompos, Arnold; Jiang, Steve B; Parodi, Katia; Jia, Xun

    2018-01-01

    One of the major benefits of carbon ion therapy is enhanced biological effectiveness at the Bragg peak region. For intensity modulated carbon ion therapy (IMCT), it is desirable to use Monte Carlo (MC) methods to compute the properties of each pencil beam spot for treatment planning, because of their accuracy in modeling physics processes and estimating biological effects. We previously developed goCMC, a graphics processing unit (GPU)-oriented MC engine for carbon ion therapy. The purpose of the present study was to build a biological treatment plan optimization system using goCMC. The repair-misrepair-fixation model was implemented to compute the spatial distribution of linear-quadratic model parameters for each spot. A treatment plan optimization module was developed to minimize the difference between the prescribed and actual biological effect. We used a gradient-based algorithm to solve the optimization problem. The system was embedded in the Varian Eclipse treatment planning system under a client-server architecture to achieve a user-friendly planning environment. We tested the system with a 1-dimensional homogeneous water case and 3 3-dimensional patient cases. Our system generated treatment plans with biological spread-out Bragg peaks covering the targeted regions and sparing critical structures. Using 4 NVidia GTX 1080 GPUs, the total computation time, including spot simulation, optimization, and final dose calculation, was 0.6 hour for the prostate case (8282 spots), 0.2 hour for the pancreas case (3795 spots), and 0.3 hour for the brain case (6724 spots). The computation time was dominated by MC spot simulation. We built a biological treatment plan optimization system for IMCT that performs simulations using a fast MC engine, goCMC. To the best of our knowledge, this is the first time that full MC-based IMCT inverse planning has been achieved in a clinically viable time frame. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Limited Advantages of Intensity-Modulated Radiotherapy Over 3D Conformal Radiation Therapy in the Adjuvant Management of Gastric Cancer

    International Nuclear Information System (INIS)

    Alani, Shlomo; Soyfer, Viacheslav; Strauss, Natan; Schifter, Dan; Corn, Benjamin W.

    2009-01-01

    Purpose: Although chemoradiotherapy was considered the standard adjuvant treatment for gastric cancer, a recent Phase III trial (Medical Research Council Adjuvant Gastric Infusional Chemotherapy [MAGIC]) did not include radiotherapy in the randomization scheme because it was considered expendable. Given radiotherapy's potential, efforts needed to be made to optimize its use for treating gastric cancer. We assessed whether intensity-modulated radiotherapy (IMRT) could improve upon our published results in patients treated with three-dimensional (3D) conformal therapy. Methods and Materials: Fourteen patients with adenocarcinoma of the stomach were treated with adjuvant chemoradiotherapy using a noncoplanar four-field arrangement. Subsequently, a nine-field IMRT plan was designed using a CMS Xio IMRT version 4.3.3 module. Two IMRT beam arrangements were evaluated: beam arrangement 1 consisted of gantry angles of 0 deg., 53 deg., 107 deg., 158 deg., 204 deg., 255 deg., and 306 deg.. Beam arrangement 2 consisted of gantry angles of 30 deg., 90 deg., 315 deg., and 345 deg.; a gantry angle of 320 deg./couch, 30 deg.; and a gantry angle of 35 o /couch, 312 o . Both the target volume coverage and the dose deposition in adjacent critical organs were assessed in the plans. Dose-volume histograms were generated for the clinical target volume, kidneys, spine, and liver. Results: Comparison of the clinical target volumes revealed satisfactory coverage by the 95% isodose envelope using either IMRT or 3D conformal therapy. However, IMRT was only marginally better than 3D conformal therapy at protecting the spine and kidneys from radiation. Conclusions: IMRT confers only a marginal benefit in the adjuvant treatment of gastric cancer and should be used only in the small subset of patients with risk factors for kidney disease or those with a preexisting nephropathy.

  19. Limited advantages of intensity-modulated radiotherapy over 3D conformal radiation therapy in the adjuvant management of gastric cancer.

    Science.gov (United States)

    Alani, Shlomo; Soyfer, Viacheslav; Strauss, Natan; Schifter, Dan; Corn, Benjamin W

    2009-06-01

    Although chemoradiotherapy was considered the standard adjuvant treatment for gastric cancer, a recent Phase III trial (Medical Research Council Adjuvant Gastric Infusional Chemotherapy [MAGIC]) did not include radiotherapy in the randomization scheme because it was considered expendable. Given radiotherapy's potential, efforts needed to be made to optimize its use for treating gastric cancer. We assessed whether intensity-modulated radiotherapy (IMRT) could improve upon our published results in patients treated with three-dimensional (3D) conformal therapy. Fourteen patients with adenocarcinoma of the stomach were treated with adjuvant chemoradiotherapy using a noncoplanar four-field arrangement. Subsequently, a nine-field IMRT plan was designed using a CMS Xio IMRT version 4.3.3 module. Two IMRT beam arrangements were evaluated: beam arrangement 1 consisted of gantry angles of 0 degrees , 53 degrees , 107 degrees , 158 degrees , 204 degrees , 255 degrees , and 306 degrees . Beam arrangement 2 consisted of gantry angles of 30 degrees , 90 degrees , 315 degrees , and 345 degrees ; a gantry angle of 320 degrees /couch, 30 degrees ; and a gantry angle of 35 degrees /couch, 312 degrees . Both the target volume coverage and the dose deposition in adjacent critical organs were assessed in the plans. Dose-volume histograms were generated for the clinical target volume, kidneys, spine, and liver. Comparison of the clinical target volumes revealed satisfactory coverage by the 95% isodose envelope using either IMRT or 3D conformal therapy. However, IMRT was only marginally better than 3D conformal therapy at protecting the spine and kidneys from radiation. IMRT confers only a marginal benefit in the adjuvant treatment of gastric cancer and should be used only in the small subset of patients with risk factors for kidney disease or those with a preexisting nephropathy.

  20. SU-E-J-274: Responses of Medulloblastoma Cells to Radiation Dosimetric Parameters in Intensity-Modulated Radiation Therapy

    International Nuclear Information System (INIS)

    Park, J; Park, J; Rogalla, S; Contag, C; Woo, D; Lee, D; Park, H; Suh, T

    2015-01-01

    Purpose: To evaluate radiation responses of the medulloblastoma cell line Daoy in intensity-modulated radiation therapy (IMRT), quantitative variations to variable radiation dosimetic parameters were tracked by bioluminescent images (BLIs). Methods: The luciferase and green fluorescent protein positive Daoy cells were cultured on dishes. The medulloblastoma cells irradiated to different dose rate, interval of fractionated doses, field margin and misalignment, and dose uniformity in IMRT were monitored using bioluminescent images. The cultured cells were placed into a dedicated acrylic phantom to deliver intensity-modulated fluences and calculate accurate predicted dose distribution. The radiation with dose rate from 0.5 Gy/min to 15 Gy/min was irradiated by adjusting monitor unit per minute and source-to-surface distances. The intervals of fractionated dose delivery were changed considering the repair time of double strand breaks (DSB) revealed by straining of gamma-H2AX.The effect of non-uniform doses on the cells were visualized by registering dose distributions and BLIs. The viability according to dosimetric parameters was correlated with bioluminescent intensities for cross-check of radiation responses. Results: The DSB and cell responses due to the first fractionated dose delivery significantly affected final tumor control rather than other parameters. The missing tumor volumes due to the smaller field margin than the tumor periphery or field misalignment caused relapse of cell responses on BLIs. The dose rate and gradient had effect on initial responses but could not bring out the distinguishable killing effect on cancer cells. Conclusion: Visualized and quantified bioluminescent images were useful to correlate the dose distributions with spatial radiation effects on cells. This would derive the effective combination of dose delivery parameters and fractionation. Radiation responses in particular IMRT configuration could be reflected to image based-dose re-optimization

  1. Can We Advance Proton Therapy for Prostate? Considering Alternative Beam Angles and Relative Biological Effectiveness Variations When Comparing Against Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, Tracy, E-mail: tunderwood@mgh.harvard.edu [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (United States); Department of Medical Physics and Bioengineering, University College London, London (United Kingdom); Giantsoudi, Drosoula; Moteabbed, Maryam; Zietman, Anthony; Efstathiou, Jason; Paganetti, Harald; Lu, Hsiao-Ming [Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (United States)

    2016-05-01

    Purpose: For prostate treatments, robust evidence regarding the superiority of either intensity modulated radiation therapy (IMRT) or proton therapy is currently lacking. In this study we investigated the circumstances under which proton therapy should be expected to outperform IMRT, particularly the proton beam orientations and relative biological effectiveness (RBE) assumptions. Methods and Materials: For 8 patients, 4 treatment planning strategies were considered: (A) IMRT; (B) passively scattered standard bilateral (SB) proton beams; (C) passively scattered anterior oblique (AO) proton beams, and (D) AO intensity modulated proton therapy (IMPT). For modalities (B)-(D) the dose and linear energy transfer (LET) distributions were simulated using the TOPAS Monte Carlo platform and RBE was calculated according to 3 different models. Results: Assuming a fixed RBE of 1.1, our implementation of IMRT outperformed SB proton therapy across most normal tissue metrics. For the scattered AO proton plans, application of the variable RBE models resulted in substantial hotspots in rectal RBE weighted dose. For AO IMPT, it was typically not possible to find a plan that simultaneously met the tumor and rectal constraints for both fixed and variable RBE models. Conclusion: If either a fixed RBE of 1.1 or a variable RBE model could be validated in vivo, then it would always be possible to use AO IMPT to dose-boost the prostate and improve normal tissue sparing relative to IMRT. For a cohort without rectum spacer gels, this study (1) underlines the importance of resolving the question of proton RBE within the framework of an IMRT versus proton debate for the prostate and (2) highlights that without further LET/RBE model validation, great care must be taken if AO proton fields are to be considered for prostate treatments.

  2. SU-E-T-353: Decoding the Beam Complexity in Intensity-Modulated Radiation Therapy Plans

    International Nuclear Information System (INIS)

    Du, W; Cho, S; Zhang, X; Hoffman, K; Kudchadker, R

    2014-01-01

    Purpose: Modern IMRT relies on computers to generate treatment plans of varied complexity. A highly complex treatment plan may use a large number of small and irregular beam apertures in order to achieve high dose conformity. However, excessive beam complexity can increase dosimetric uncertainty, prolong treatment time, and increase susceptibility to target or organ motion. In this study we sought to develop metrics to assess the complexity of IMRT beams and plans. Methods: Based the information of leaf positions and MU for each beam segment, we calculated the following beam complexity metrics: aperture area, shape irregularity, and beam modulation. Then these beam complexity metrics were averaged to obtain the corresponding plan complexity metrics, using the beam MUs as weighting factors. We evaluated and compared the beam and plan complexity scores for 65 IMRT plans from 3 sites (prostate, head and neck, and spine). We also studied how the plan complexity scores were affected by adjusting inverse planning parameters. Results: For prostate IMRT, the lateral beams had large MUs and smaller shape irregularity, while the anterior or posterior beams had larger modulation values. On average, the prostate IMRT plans had the smallest shape irregularity and beam modulation; the HN IMRT plans had the largest aperture area, shape irregularity, and beam modulation; and the spine stereotactic IMRT plans often had small aperture area, which may be associated with relatively large discrepancies between calculated and measures doses. The plan complexity increased as the number of optimization iterations and the number of beam segments increased and as the minimum segment area decreased. Conclusion: Complexity of IMRT beams and plans were quantified in terms of aperture area, shape irregularity and beam modulation. The complexity metrics varied among IMRT plans for different disease sites and were affected when the planning parameters were adjusted

  3. Risk Factors for Pelvic Insufficiency Fractures in Locally Advanced Cervical Cancer Following Intensity Modulated Radiation Therapy

    DEFF Research Database (Denmark)

    Ramlov, Anne; Pedersen, Erik Morre; Røhl, Lisbeth

    2017-01-01

    and underwent external beam radiation therapy with 45 Gy in 25 fractions (node-negative patients) or 50 Gy in 25 fractions with a simultaneous integrated boost of 60 Gy in 30 fractions (node-positive patients). Pulsed dose rate magnetic resonance imaging guided adaptive brachytherapy was given in addition......PURPOSE: To investigate the incidence of and risk factors for pelvic insufficiency fracture (PIF) after definitive chemoradiation therapy for locally advanced cervical cancer (LACC). METHODS AND MATERIALS: We analyzed 101 patients with LACC treated from 2008-2014. Patients received weekly cisplatin...

  4. Acute toxicity in comprehensive head and neck radiation for nasopharynx and paranasal sinus cancers: cohort comparison of 3D conformal proton therapy and intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    McDonald, Mark W.; Liu, Yuan; Moore, Michael G.; Johnstone, Peter A. S.

    2016-01-01

    To evaluate acute toxicity endpoints in a cohort of patients receiving head and neck radiation with proton therapy or intensity modulated radiation therapy (IMRT). Forty patients received comprehensive head and neck radiation including bilateral cervical nodal radiation, given with or without chemotherapy, for tumors of the nasopharynx, nasal cavity or paranasal sinuses, any T stage, N0-2. Fourteen received comprehensive treatment with proton therapy, and 26 were treated with IMRT, either comprehensively or matched to proton therapy delivered to the primary tumor site. Toxicity endpoints assessed included g-tube dependence at the completion of radiation and at 3 months after radiation, opioid pain medication requirement compared to pretreatment normalized as equivalent morphine dose (EMD) at completion of treatment, and at 1 and 3 months after radiation. In a multivariable model including confounding variables of concurrent chemotherapy and involved nodal disease, comprehensive head and neck radiation therapy using proton therapy was associated with a lower opioid pain requirement at the completion of radiation and a lower rate of gastrostomy tube dependence by the completion of radiation therapy and at 3 months after radiation compared to IMRT. Proton therapy was associated with statistically significant lower mean doses to the oral cavity, esophagus, larynx, and parotid glands. In subgroup analysis of 32 patients receiving concurrent chemotherapy, there was a statistically significant correlation with a greater opioid pain medication requirement at the completion of radiation and both increasing mean dose to the oral cavity and to the esophagus. Proton therapy was associated with significantly reduced radiation dose to assessed non-target normal tissues and a reduced rate of gastrostomy tube dependence and opioid pain medication requirements. This warrants further evaluation in larger studies, ideally with patient-reported toxicity outcomes and quality of life

  5. Evaluation of a mixed beam therapy for post-mastectomy breast cancer patients: bolus electron conformal therapy combined with intensity modulated photon radiotherapy and volumetric modulated photon arc therapy.

    Science.gov (United States)

    Zhang, Rui; Heins, David; Sanders, Mary; Guo, Beibei; Hogstrom, Kenneth

    2018-05-10

    The purpose of this study was to assess the potential benefits and limitations of a mixed beam therapy, which combined bolus electron conformal therapy (BECT) with intensity modulated photon radiotherapy (IMRT) and volumetric modulated photon arc therapy (VMAT), for left-sided post-mastectomy breast cancer patients. Mixed beam treatment plans were produced for nine post-mastectomy radiotherapy (PMRT) patients previously treated at our clinic with VMAT alone. The mixed beam plans consisted of 40 Gy to the chest wall area using BECT, 40 Gy to the supraclavicular area using parallel opposed IMRT, and 10 Gy to the total planning target volume (PTV) by optimizing VMAT on top of the BECT+IMRT dose distribution. The treatment plans were created in a commercial treatment planning system (TPS), and all plans were evaluated based on PTV coverage, dose homogeneity index (DHI), conformity index (CI), dose to organs at risk (OARs), normal tissue complication probability (NTCP), and secondary cancer complication probability (SCCP). The standard VMAT alone planning technique was used as the reference for comparison. Both techniques produced clinically acceptable PMRT plans but with a few significant differences: VMAT showed significantly better CI (0.70 vs. 0.53, p 0.5 cm and volume of tissue between the distal PTV surface and heart or lung approximately > 250 cm 3 ) between distal PTV surface and lung may benefit the most from mixed beam therapy. This work has demonstrated that mixed beam therapy (BECT+IMRT : VMAT = 4 : 1) produces clinically acceptable plans having reduced OAR doses and risks of side effects compared with VMAT. Even though VMAT alone produces more homogenous and conformal dose distributions, mixed beam therapy remains as a viable option for treating post-mastectomy patients, possibly leading to reduced normal tissue complications. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  6. Four-Week Course of Radiation for Breast Cancer Using Hypofractionated Intensity Modulated Radiation Therapy With an Incorporated Boost

    International Nuclear Information System (INIS)

    Freedman, Gary M.; Anderson, Penny R.; Goldstein, Lori J.; Ma Changming; Li Jinsheng; Swaby, Ramona F.; Litwin, Samuel; Watkins-Bruner, Deborah; Sigurdson, Elin R.; Morrow, Monica

    2007-01-01

    Purpose: Standard radiation for early breast cancer requires daily treatment for 6 to 7 weeks. This is an inconvenience to many women, and for some a barrier for breast conservation. We present the acute toxicity of a 4-week course of hypofractionated radiation. Methods and Materials: A total of 75 patients completed radiation on a Phase II trial approved by the hospital institutional review board. Eligibility criteria were broad to include any patient normally eligible for standard radiation: age ≥18 years, invasive or in situ cancer, American Joint Committee on Cancer Stage 0 to II, breast-conserving surgery, and any systemic therapy not given concurrently. The median age was 52 years (range, 31-81 years). Of the patients, 15% had ductal carcinoma in situ, 67% T1, and 19% T2; 71% were N0, 17% N1, and 12% NX. Chemotherapy was given before radiation in 44%. Using photon intensity-modulated radiation therapy and incorporated electron beam boost, the whole breast received 45 Gy and the lumpectomy bed 56 Gy in 20 treatments over 4 weeks. Results: The maximum acute skin toxicity by the end of treatment was Grade 0 in 9 patients (12%), Grade 1 in 49 (65%) and Grade 2 in 17 (23%). There was no Grade 3 or higher skin toxicity. After radiation, all Grade 2 toxicity had resolved by 6 weeks. Hematologic toxicity was Grade 0 in most patients except for Grade 1 neutropenia in 2 patients, and Grade 1 anemia in 11 patients. There were no significant differences in baseline vs. 6-week posttreatment patient-reported or physician-reported cosmetic scores. Conclusions: This 4-week course of postoperative radiation using intensity-modulated radiation therapy is feasible and is associated with acceptable acute skin toxicity and quality of life. Long-term follow-up data are needed. This radiation schedule may represent an alternative both to longer 6-week to 7-week standard whole-breast radiation and more radically shortened 1-week, partial-breast treatment schedules

  7. The Quality Control of Intensity Modulated Radiation Therapy (IMRT for ONCOR Siemens Linear Accelerators Using Film Dosimetry

    Directory of Open Access Journals (Sweden)

    Keyvan Jabbari

    2012-03-01

    Full Text Available Introduction Intensity Modulated Radiation Therapy (IMRT has made a significant progress in radiation therapy centers in recent years. In this method, each radiation beam is divided into many subfields that create a field with a modulated intensity. Considering the complexity of this method, the quality control for IMRT is a topic of interest for researchers. This article is about the various steps of planning and quality control of Siemens linear accelerators for IMRT, using film dosimetry. This article in addition to review of the techniques, discusses the details of experiments and possible sources of errors which are not mentioned in the protocols and other references. Materials and Methods This project was carried out in Isfahan Milad hospital which has two Siemens ONCOR linear accelerators. Both accelerators are equipped with Multi-Leaf Collimators (MLC which enables us to perform IMRT delivery in the step-and-shoot method. The quality control consists of various experiments related to the sections of radiation therapy. In these experiments, the accuracy of some components such as treatment planning system, imaging device (CT, MLC, control system of accelerator, and stability of the output are evaluated. The dose verification is performed using film dosimetry method. The films were KODAK-EDR2, which were calibrated before the experiments. One of the important steps is the comparison of the calculated dose with planning system and the measured dose in experiments. Results The results of the experiments in various steps have been acceptable according to the standard protocols. The calibration of MLC and evaluation of the leakage through the leaves of MLC was performed by using the film dosimetry and visual check. In comparison with calculated and measured dose, more that 80% of the points have to be in agreement within 3% of the value. In our experiments, between 85 and 90% of the points had such an agreement with IMRT delivery. Conclusion

  8. Lithium formate EPR dosimetry for verifications of planned dose distributions prior to intensity-modulated radiation therapy

    Science.gov (United States)

    Gustafsson, H.; Lund, E.; Olsson, S.

    2008-09-01

    The objective of the present investigation was to evaluate lithium formate electron paramagnetic resonance (EPR) dosimetry for measurement of dose distributions in phantoms prior to intensity-modulated radiation therapy (IMRT). Lithium formate monohydrate tablets were carefully prepared, and blind tests were performed in clinically relevant situations in order to determine the precision and accuracy of the method. Further experiments confirmed that within the accuracy of the current method, the dosimeter response was independent of beam energies and dose rates used for IMRT treatments. The method was applied to IMRT treatment plans, and the dose determinations were compared to ionization chamber measurements. The experiments showed that absorbed doses above 3 Gy could be measured with an uncertainty of less than 2.5% of the dose (coverage factor k = 1.96). Measurement time was about 15 min using a well-calibrated dosimeter batch. The conclusion drawn from the investigation was that lithium formate EPR dosimetry is a promising new tool for absorbed dose measurements in external beam radiation therapy, especially for doses above 3 Gy.

  9. Lithium formate EPR dosimetry for verifications of planned dose distributions prior to intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, H; Lund, E [Department of Medical and Health Sciences, Radiation Physics, Faculty of Health Sciences, Linkoeping University, S-581 85 Linkoeping (Sweden); Olsson, S [Division of Radiation Physics, Linkoeping University Hospital, S-581 85 Linkoeping (Sweden)], E-mail: hakgu@imv.liu.se

    2008-09-07

    The objective of the present investigation was to evaluate lithium formate electron paramagnetic resonance (EPR) dosimetry for measurement of dose distributions in phantoms prior to intensity-modulated radiation therapy (IMRT). Lithium formate monohydrate tablets were carefully prepared, and blind tests were performed in clinically relevant situations in order to determine the precision and accuracy of the method. Further experiments confirmed that within the accuracy of the current method, the dosimeter response was independent of beam energies and dose rates used for IMRT treatments. The method was applied to IMRT treatment plans, and the dose determinations were compared to ionization chamber measurements. The experiments showed that absorbed doses above 3 Gy could be measured with an uncertainty of less than 2.5% of the dose (coverage factor k = 1.96). Measurement time was about 15 min using a well-calibrated dosimeter batch. The conclusion drawn from the investigation was that lithium formate EPR dosimetry is a promising new tool for absorbed dose measurements in external beam radiation therapy, especially for doses above 3 Gy.

  10. Skin dose for head and neck cancer patients treated with intensity-modulated radiation therapy(IMRT)

    Science.gov (United States)

    Fu, Hsiao-Ju; Li, Chi-Wei; Tsai, Wei-Ta; Chang, Chih-Chia; Tsang, Yuk-Wah

    2017-11-01

    The reliability of thermoluminescent dosimeters (ultrathin TLD) and ISP Gafchromic EBT2 film to measure the surface dose in phantom and the skin dose in head-and-neck patients treated with intensity-modulated radiation therapy technique(IMRT) is the research focus. Seven-field treatment plans with prescribed dose of 180 cGy were performed on Eclipse treatment planning system which utilized pencil beam calculation algorithm(PBC). In calibration tests, the variance coefficient of the ultrathin TLDs were within 3%. The points on the calibration curve of the Gafchromic film was within 1% variation. Five measurements were taken on phantom using ultrathin TLD and EBT2 film respectively. The measured mean surface doses between ultrathin TLD or EBT2 film were within 5% deviation. Skin doses of 6 patients were measured for initial 5 fractions and the mean dose per-fraction was calculated. If the extrapolated doses for 30 fractions were below 4000 cGy, the skin reaction grading observed according to Radiation Therapy Oncology Group (RTOG) was either grade 1 or grade 2. If surface dose exceeded 5000 cGy in 32 fractions, then grade 3 skin reactions were observed.

  11. Simultaneous minimizing monitor units and number of segments without leaf end abutment for segmental intensity modulated radiation therapy delivery

    International Nuclear Information System (INIS)

    Li Kaile; Dai Jianrong; Ma Lijun

    2004-01-01

    Leaf end abutment is seldom studied when delivering segmental intensity modulated radiation therapy (IMRT) fields. We developed an efficient leaf sequencing method to eliminate leaf end abutment for segmental IMRT delivery. Our method uses simple matrix and sorting operations to obtain a solution that simultaneously minimizes total monitor units and number of segments without leaf end abutment between segments. We implemented and demonstrated our method for multiple clinical cases. We compared the results of our method with the results from exhaustive search method. We found that our solution without leaf end abutment produced equivalent results to the unconstrained solutions in terms of minimum total monitor units and minimum number of leaf segments. We conclude that the leaf end abutment fields can be avoided without affecting the efficiency of segmental IMRT delivery. The major strength of our method is its simplicity and high computing speed. This potentially provides a useful means for generating segmental IMRT fields that require high spatial resolution or complex intensity distributions

  12. Dosimetric comparison to the heart and cardiac substructure in a large cohort of esophageal cancer patients treated with proton beam therapy or Intensity-modulated radiation therapy.

    Science.gov (United States)

    Shiraishi, Yutaka; Xu, Cai; Yang, Jinzhong; Komaki, Ritsuko; Lin, Steven H

    2017-10-01

    To compare heart and cardiac substructure radiation exposure using intensity-modulated radiotherapy (IMRT) vs. proton beam therapy (PBT) for patients with mid- to distal esophageal cancer who received chemoradiation therapy. We identified 727 esophageal cancer patients who received IMRT (n=477) or PBT (n=250) from March 2004 to December 2015. All patients were treated to 50.4Gy with IMRT or to 50.4 cobalt Gray equivalents with PBT. IMRT and PBT dose-volume histograms (DVHs) of the whole heart, atria, ventricles, and four coronary arteries were compared. For PBT patients, passive scattering proton therapy (PSPT; n=237) and intensity-modulated proton therapy (IMPT; n=13) DVHs were compared. Compared with IMRT, PBT resulted in significantly lower mean heart dose (MHD) and heart V5, V10, V20, V30, and V40as well as lower radiation exposure to the four chambers and four coronary arteries. Compared with PSPT, IMPT resulted in significantly lower heart V20, V30, and V40 but not MHD or heart V5 or V10. IMPT also resulted in significantly lower radiation doses to the left atrium, right atrium, left main coronary artery, and left circumflex artery, but not the left ventricle, right ventricle, left anterior descending artery, or right coronary artery. Factors associated with lower MHD included PBT (Pheart and cardiac substructures than IMRT. Long-term studies are necessary to determine how this cardiac sparing effect impacts the development of coronary artery disease and other cardiac complications. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. TU-EF-304-07: Monte Carlo-Based Inverse Treatment Plan Optimization for Intensity Modulated Proton Therapy

    International Nuclear Information System (INIS)

    Li, Y; Tian, Z; Jiang, S; Jia, X; Song, T; Wu, Z; Liu, Y

    2015-01-01

    Purpose: Intensity-modulated proton therapy (IMPT) is increasingly used in proton therapy. For IMPT optimization, Monte Carlo (MC) is desired for spots dose calculations because of its high accuracy, especially in cases with a high level of heterogeneity. It is also preferred in biological optimization problems due to the capability of computing quantities related to biological effects. However, MC simulation is typically too slow to be used for this purpose. Although GPU-based MC engines have become available, the achieved efficiency is still not ideal. The purpose of this work is to develop a new optimization scheme to include GPU-based MC into IMPT. Methods: A conventional approach using MC in IMPT simply calls the MC dose engine repeatedly for each spot dose calculations. However, this is not the optimal approach, because of the unnecessary computations on some spots that turned out to have very small weights after solving the optimization problem. GPU-memory writing conflict occurring at a small beam size also reduces computational efficiency. To solve these problems, we developed a new framework that iteratively performs MC dose calculations and plan optimizations. At each dose calculation step, the particles were sampled from different spots altogether with Metropolis algorithm, such that the particle number is proportional to the latest optimized spot intensity. Simultaneously transporting particles from multiple spots also mitigated the memory writing conflict problem. Results: We have validated the proposed MC-based optimization schemes in one prostate case. The total computation time of our method was ∼5–6 min on one NVIDIA GPU card, including both spot dose calculation and plan optimization, whereas a conventional method naively using the same GPU-based MC engine were ∼3 times slower. Conclusion: A fast GPU-based MC dose calculation method along with a novel optimization workflow is developed. The high efficiency makes it attractive for clinical

  14. TU-EF-304-07: Monte Carlo-Based Inverse Treatment Plan Optimization for Intensity Modulated Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y [Tsinghua University, Beijing, Beijing (China); UT Southwestern Medical Center, Dallas, TX (United States); Tian, Z; Jiang, S; Jia, X [UT Southwestern Medical Center, Dallas, TX (United States); Song, T [Southern Medical University, Guangzhou, Guangdong (China); UT Southwestern Medical Center, Dallas, TX (United States); Wu, Z; Liu, Y [Tsinghua University, Beijing, Beijing (China)

    2015-06-15

    Purpose: Intensity-modulated proton therapy (IMPT) is increasingly used in proton therapy. For IMPT optimization, Monte Carlo (MC) is desired for spots dose calculations because of its high accuracy, especially in cases with a high level of heterogeneity. It is also preferred in biological optimization problems due to the capability of computing quantities related to biological effects. However, MC simulation is typically too slow to be used for this purpose. Although GPU-based MC engines have become available, the achieved efficiency is still not ideal. The purpose of this work is to develop a new optimization scheme to include GPU-based MC into IMPT. Methods: A conventional approach using MC in IMPT simply calls the MC dose engine repeatedly for each spot dose calculations. However, this is not the optimal approach, because of the unnecessary computations on some spots that turned out to have very small weights after solving the optimization problem. GPU-memory writing conflict occurring at a small beam size also reduces computational efficiency. To solve these problems, we developed a new framework that iteratively performs MC dose calculations and plan optimizations. At each dose calculation step, the particles were sampled from different spots altogether with Metropolis algorithm, such that the particle number is proportional to the latest optimized spot intensity. Simultaneously transporting particles from multiple spots also mitigated the memory writing conflict problem. Results: We have validated the proposed MC-based optimization schemes in one prostate case. The total computation time of our method was ∼5–6 min on one NVIDIA GPU card, including both spot dose calculation and plan optimization, whereas a conventional method naively using the same GPU-based MC engine were ∼3 times slower. Conclusion: A fast GPU-based MC dose calculation method along with a novel optimization workflow is developed. The high efficiency makes it attractive for clinical

  15. Treatment with intensity-modulated radiation therapy (IMRT) for breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Marta, G.N.; Hanna, S.A.; Gadia, R.

    2014-11-15

    Through the development of four relevant clinical questions related with the proposed subject, we tried to present the main evidence for safety, toxicity and effectiveness using different radiotherapy techniques. The study population consisted of female patients of all ages with primary breast cancer treated with radiation therapy to the whole breast, regardless of histological type, staging, context of treatment (radical, adjuvant or palliative) and whether comorbidities were present or not. For this, a systematic review of the literature was performed in primary scientific research databases (Medline - Pubmed; Embase - Elsevier; Lilacs - Bireme; Cochrane Library - Central Register of Controlled Trials). All articles available until July 22, 2013, were included. The search strategy used for Medline research is described in Appendix. Articles were selected based on critical evaluation in search of the best available evidence. Recommendations were prepared based on discussion with the writing group, composed of three members of the Brazilian Society of Radiotherapy. The guideline was reviewed by an independent group specializing in evidence-based clinical guidelines. After completion, the guideline was made available for public consultation for 15 days and the suggestions forwarded to the writers for evaluation and consideration into the final text. Objective: to assess the most appropriate method of radiation therapy for treating patients with primary breast tumors. (author)

  16. SU-F-T-539: Dosimetric Comparison of Volumetric Modulated Arc Therapy and Intensity Modulated Radiation Therapy for Whole Brain Hippocampal Sparing Radiation Therapy Treatments

    Energy Technology Data Exchange (ETDEWEB)

    Kendall, E; Higby, C; Algan, O; Ahmad, S; Hossain, S [University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States)

    2016-06-15

    Purpose: To compare the treatment plan quality and dose gradient near the hippocampus between VMAT (RapidArc) and IMRT delivery techniques for whole brain radiation therapy. Methods: Fifteen patients were evaluated in this retrospective study. All treatments were planned on Varian Eclipse TPS, using 3-Arc VMAT and 9-Field IMRT, following NRG Oncology protocol NRG-CC001 guidelines evaluated by a single radiation oncologist. Prescribed doses in all plans were 30 Gy delivered over 10 fractions normalized to a minimum of 100% of the dose covering 95% of the target volume. Identical contour sets and dose-volume constraints following protocol guidelines were also applied in all plans. A paired t-test analysis was used to compare VMAT and IMRT plans. Results: NRG-CC001 protocol dose-volume constraints were met for all VMAT and IMRT plans. For the planning target volume (PTV), the average values for D2% and D98% were 6% lower and 4% higher in VMAT than in IMRT, respectively. The average mean and maximum hippocampus doses in Gy for VMAT vs IMRT plans were (11.85±0.81 vs. 12.24±0.56, p=0.10) and (16.27±0.78 vs. 16.59±0.71, p=0.24), respectively. In VMAT, the average mean and maximum chiasm doses were 3% and 1% higher than in IMRT plans, respectively. For the left optic nerve, the average mean and maximum doses were 10% and 5% higher in VMAT than in IMRT plans, respectively. These values were 12% and 3% for the right optic nerve. The average percentage of dose gradient around the hippocampus in the 0–5mm and 5–10mm abutted regions for VMAT vs. IMRT were (4.42%±2.22% /mm vs. 3.95%±2.61% /mm, p=0.43) and (4.54%±1.50% /mm vs. 4.39%±1.28% /mm, p=0.73), respectively. Conclusion: VMAT plans can achieve higher hippocampus sparing with a faster dose fall-off than IMRT plans. Though statistically insignificant, VMAT offers better PTV coverage with slightly higher doses to OARs.

  17. SU-F-T-539: Dosimetric Comparison of Volumetric Modulated Arc Therapy and Intensity Modulated Radiation Therapy for Whole Brain Hippocampal Sparing Radiation Therapy Treatments

    International Nuclear Information System (INIS)

    Kendall, E; Higby, C; Algan, O; Ahmad, S; Hossain, S

    2016-01-01

    Purpose: To compare the treatment plan quality and dose gradient near the hippocampus between VMAT (RapidArc) and IMRT delivery techniques for whole brain radiation therapy. Methods: Fifteen patients were evaluated in this retrospective study. All treatments were planned on Varian Eclipse TPS, using 3-Arc VMAT and 9-Field IMRT, following NRG Oncology protocol NRG-CC001 guidelines evaluated by a single radiation oncologist. Prescribed doses in all plans were 30 Gy delivered over 10 fractions normalized to a minimum of 100% of the dose covering 95% of the target volume. Identical contour sets and dose-volume constraints following protocol guidelines were also applied in all plans. A paired t-test analysis was used to compare VMAT and IMRT plans. Results: NRG-CC001 protocol dose-volume constraints were met for all VMAT and IMRT plans. For the planning target volume (PTV), the average values for D2% and D98% were 6% lower and 4% higher in VMAT than in IMRT, respectively. The average mean and maximum hippocampus doses in Gy for VMAT vs IMRT plans were (11.85±0.81 vs. 12.24±0.56, p=0.10) and (16.27±0.78 vs. 16.59±0.71, p=0.24), respectively. In VMAT, the average mean and maximum chiasm doses were 3% and 1% higher than in IMRT plans, respectively. For the left optic nerve, the average mean and maximum doses were 10% and 5% higher in VMAT than in IMRT plans, respectively. These values were 12% and 3% for the right optic nerve. The average percentage of dose gradient around the hippocampus in the 0–5mm and 5–10mm abutted regions for VMAT vs. IMRT were (4.42%±2.22% /mm vs. 3.95%±2.61% /mm, p=0.43) and (4.54%±1.50% /mm vs. 4.39%±1.28% /mm, p=0.73), respectively. Conclusion: VMAT plans can achieve higher hippocampus sparing with a faster dose fall-off than IMRT plans. Though statistically insignificant, VMAT offers better PTV coverage with slightly higher doses to OARs.

  18. Breast Intensity-Modulated Radiation Therapy Reduces Time Spent With Acute Dermatitis for Women of All Breast Sizes During Radiation

    International Nuclear Information System (INIS)

    Freedman, Gary M.; Li Tianyu; Nicolaou, Nicos; Chen Yan; Ma, Charlie C.-M.; Anderson, Penny R.

    2009-01-01

    Purpose: To study the time spent with radiation-induced dermatitis during a course of radiation therapy for breast cancer in women treated with conventional or intensity-modulated radiation therapy (IMRT). Methods and Materials: The study population consisted of 804 consecutive women with early-stage breast cancer treated with breast-conserving surgery and radiation from 2001 to 2006. All patients were treated with whole-breast radiation followed by a boost to the tumor bed. Whole-breast radiation consisted of conventional wedged photon tangents (n = 405) earlier in the study period and mostly of photon IMRT (n = 399) in later years. All patients had acute dermatitis graded each week of treatment. Results: The breakdown of the cases of maximum acute dermatitis by grade was as follows: 3%, Grade 0; 34%, Grade 1; 61%, Grade 2; and 2%, Grade 3. The breakdown of cases of maximum toxicity by technique was as follows: 48%, Grade 0/1, and 52%, Grade 2/3, for IMRT; and 25%, Grade 0/1, and 75%, Grade 2/3, for conventional radiation therapy (p < 0.0001). The IMRT patients spent 82% of weeks during treatment with Grade 0/1 dermatitis and 18% with Grade 2/3 dermatitis, compared with 29% and 71% of patients, respectively, treated with conventional radiation (p < 0.0001). Furthermore, the time spent with Grade 2/3 toxicity was decreased in IMRT patients with small (p = 0.0015), medium (p < 0.0001), and large (p < 0.0001) breasts. Conclusions: Breast IMRT is associated with a significant decrease both in the time spent during treatment with Grade 2/3 dermatitis and in the maximum severity of dermatitis compared with that associated with conventional radiation, regardless of breast size.

  19. SU-F-J-196: A Prototype System for Portal Imaging for Intensity Modulated Neutron Therapy

    Energy Technology Data Exchange (ETDEWEB)

    St James, S; Argento, D; DeWitt, D; Miyaoka, R; Stewart, R [University of Washington, Seattle, WA (United States); Moffitt, G [University of Utah, Salt Lake City, UT (United States)

    2016-06-15

    Purpose: Fast neutron therapy is offered at the University of Washington Medical Center for treatment of selected cancers. The hardware and control systems of the UW Clinical Neutron Therapy System are undergoing upgrades to enable delivery of IMNT. To clinically implement IMNT, dose verification tools need to be developed. We propose a portal imaging system that relies on the creation of positron emitting isotopes ({sup 11}C and {sup 15}O) through (n, 2n) reactions with a PMMA plate placed below the patient. After field delivery, the plate is retrieved from the vault and imaged using a reader that detects the annihilation photons. The pattern of activity produced in the plate provides information to reconstruct the neutron fluence map that can be compared to fluence maps from Monte Carlo (MCNP) simulations to verify treatment delivery. We have previously performed Monte Carlo simulations of the portal imaging system (GATE simulations) and the beam line (MCNP simulations). In this work, initial measurements using a prototype system are presented. Methods: Custom electronics were developed for BGO detectors read out with photomultiplier tubes (previous generation PET detectors from a CTI ECAT 953 scanner). Two detectors were placed in coincidence, with a detector separation of 2 cm. Custom software was developed to create the crystal look up tables and perform a limited angle planar reconstruction with a stochastic normalization. To test the initial capabilities of the system, PMMA squares were irradiated with neutrons at a depth of 1.5 cm and read out using the prototype system. Doses ranging from 10–200 cGy were delivered. Results: Using the prototype system, dose differences in the therapeutic range could be determined. Conclusion: The prototype portal imaging system is capable of detecting neutron doses as low as 10–50 cGy and shows great promise as a patient QA tool for IMNT.

  20. 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.

  1. Patients with advanced periodontal disease before intensity-modulated radiation therapy are prone to develop bone healing problems : a 2-year prospective follow-up study

    NARCIS (Netherlands)

    Schuurhuis, Jennifer M; Stokman, Monique A; Witjes, Max J H; Reintsema, Harry; Langendijk, Johannes A; Vissink, Arjan; Spijkervet, Frederik K L

    PURPOSE: Intensity-modulated radiation therapy (IMRT) has changed radiation treatment of head and neck cancer (HNC). However, it is still unclear if and how IMRT changes oral morbidity outcomes. In this prospective study, we assessed the outcome of reducing post-IMRT sequelae by means of

  2. Limited Impact of Setup and Range Uncertainties, Breathing Motion, and Interplay Effects in Robustly Optimized Intensity Modulated Proton Therapy for Stage III Non-small Cell Lung Cancer

    NARCIS (Netherlands)

    Inoue, Tatsuya; Widder, Joachim; van Dijk, Lisanne V; Takegawa, Hideki; Koizumi, Masahiko; Takashina, Masaaki; Usui, Keisuke; Kurokawa, Chie; Sugimoto, Satoru; Saito, Anneyuko I; Sasai, Keisuke; Van't Veld, Aart A; Langendijk, Johannes A; Korevaar, Erik W

    2016-01-01

    Purpose: To investigate the impact of setup and range uncertainties, breathing motion, and interplay effects using scanning pencil beams in robustly optimized intensity modulated proton therapy (IMPT) for stage III non-small cell lung cancer (NSCLC). Methods and Materials: Three-field IMPT plans

  3. Feasibility of Pencil Beam Scanned Intensity Modulated Proton Therapy in Breath-hold for Locally Advanced Non-Small Cell Lung Cancer

    DEFF Research Database (Denmark)

    Gorgisyan, Jenny; Munck Af Rosenschold, Per; Perrin, Rosalind

    2017-01-01

    PURPOSE: We evaluated the feasibility of treating patients with locally advanced non-small cell lung cancer (NSCLC) with pencil beam scanned intensity modulated proton therapy (IMPT) in breath-hold. METHODS AND MATERIALS: Fifteen NSCLC patients who had previously received 66 Gy in 33 fractions wi...

  4. Concurrent chemotherapy with intensity-modulated radiation therapy for locally advanced squamous cell carcinoma of the larynx and oropharynx: A retrospective single-institution analysis

    NARCIS (Netherlands)

    N.F. Saba (Nabil); D.J. Edelman (David); M. Tighiouart (Mourad); J.G. Gaultney (Jennifer G.); L.W. Davis (Lawrence); F.R. Khuri (Fadlo); A. Chen (Amy); S. Grist (Scott); D.M. Shin (Dong)

    2009-01-01

    textabstractBackground. We present outcome data from concurrent chemotherapy and intensity-modulated radiation therapy (IMRT) for squamous cell carcinoma (SCC) of the larynx and oropharyx. Methods. Eighty patients with laryngeal (n = 15) or oropharyngeal (n = 65) SCC underwent concurrent IMRT and

  5. An algorithm for real-time dosimetry in intensity-modulated radiation therapy using the radioluminescence signal from Al2O3:C

    DEFF Research Database (Denmark)

    Andersen, C.E.; Marckmann, C.J.; Aznar, Marianne

    2006-01-01

    radiation beams. The dosimetry system has been used for dose measurements in a phantom during an intensity-modulated radiation therapy (IMRT) treatment with 6 MV photons. The RL measurement results are in excellent agreement (i.e. within 1%) with both the OSL results and the dose delivered according...

  6. Risk Factors for Pelvic Insufficiency Fractures in Locally Advanced Cervical Cancer Following Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ramlov, Anne, E-mail: anraml@rm.dk [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Pedersen, Erik Morre; Røhl, Lisbeth [Department of Radiotherapy, Aarhus University Hospital, Aarhus (Denmark); Worm, Esben [Department of Medical Physics, Aarhus University Hospital, Aarhus (Denmark); Fokdal, Lars; Lindegaard, Jacob Chr. [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Tanderup, Kari [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Department of Medical Physics, Aarhus University Hospital, Aarhus (Denmark)

    2017-04-01

    Purpose: To investigate the incidence of and risk factors for pelvic insufficiency fracture (PIF) after definitive chemoradiation therapy for locally advanced cervical cancer (LACC). Methods and Materials: We analyzed 101 patients with LACC treated from 2008-2014. Patients received weekly cisplatin and underwent external beam radiation therapy with 45 Gy in 25 fractions (node-negative patients) or 50 Gy in 25 fractions with a simultaneous integrated boost of 60 Gy in 30 fractions (node-positive patients). Pulsed dose rate magnetic resonance imaging guided adaptive brachytherapy was given in addition. Follow-up magnetic resonance imaging was performed routinely at 3 and 12 months after the end of treatment or based on clinical indication. PIF was defined as a fracture line with or without sclerotic changes in the pelvic bones. D{sub 50%} and V{sub 55Gy} were calculated for the os sacrum and jointly for the os ileum and pubis. Patient- and treatment-related factors including dose were analyzed for correlation with PIF. Results: The median follow-up period was 25 months. The median age was 50 years. In 20 patients (20%), a median of 2 PIFs (range, 1-3 PIFs) were diagnosed; half were asymptomatic. The majority of the fractures were located in the sacrum (77%). Age was a significant risk factor (P<.001), and the incidence of PIF was 4% and 37% in patients aged ≤50 years and patients aged >50 years, respectively. Sacrum D{sub 50%} was a significant risk factor in patients aged >50 years (P=.04), whereas V{sub 55Gy} of the sacrum and V{sub 55Gy} of the pelvic bones were insignificant (P=.33 and P=.18, respectively). A dose-effect curve for sacrum D{sub 50%} in patients aged >50 years showed that reduction of sacrum D{sub 50%} from 40 Gy{sub EQD2} to 35 Gy{sub EQD2} reduces PIF risk from 45% to 22%. Conclusions: PIF is common after treatment of LACC and is mainly seen in patients aged >50 years. Our data indicate that PIFs are not related to lymph node

  7. Dosimetric comparison of helical tomotherapy, intensity-modulated radiation therapy, volumetric-modulated arc therapy, and 3-dimensional conformal therapy for the treatment of T1N0 glottic cancer

    International Nuclear Information System (INIS)

    Ekici, Kemal; Pepele, Eda K.; Yaprak, Bahaddin; Temelli, Oztun; Eraslan, Aysun F.; Kucuk, Nadir; Altınok, Ayse Y.; Sut, Pelin A.; Alpak, Ozlem D.; Colak, Cemil; Mayadagli, Alpaslan

    2016-01-01

    Various radiotherapy planning methods for T1N0 laryngeal cancer have been proposed to decrease normal tissue toxicity. We compare helical tomotherapy (HT), linac-based intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT), and 3-D conformal radiotherapy (3D-CRT) techniques for T1N0 laryngeal cancer. Overall, 10 patients with T1N0 laryngeal cancer were selected and evaluated. Furthermore, 10 radiotherapy treatment plans have been created for all 10 patients, including HT, IMRT, VMAT, and 3D-CRT. IMRT, VMAT, and HT plans vs 3D-CRT plans consistently provided superior planning target volume (PTV) coverage. Similar target coverage was observed between the 3 IMRT modalities. Compared with 3D-CRT, IMRT, HT, and VMAT significantly reduced the mean dose to the carotid arteries. VMAT resulted in the lowest mean dose to the submandibular and thyroid glands. Compared with 3D-CRT, IMRT, HT, and VMAT significantly increased the maximum dose to the spinal cord It was observed that the 3 IMRT modalities studied showed superior target coverage with less variation between each plan in comparison with 3D-CRT. The 3D-CRT plans performed better at the D max of the spinal cord. Clinical investigation is warranted to determine if these treatment approaches would translate into a reduction in radiation therapy–induced toxicities.

  8. Treatment planning study comparing proton therapy, RapidArc and intensity modulated radiation therapy for a synchronous bilateral lung cancer case

    Directory of Open Access Journals (Sweden)

    Suresh Rana

    2014-03-01

    Full Text Available Purpose: The main purpose of this study is to perform a treatment planning study on a synchronous bilateral non-small cell lung cancer case using three treatment modalities: uniform scanning proton therapy, RapidArc, and intensity modulated radiation therapy (IMRT. Methods: The maximum intensity projection (MIP images obtained from the 4 dimensional-computed tomography (4DCT scans were used for delineation of tumor volumes in the left and right lungs. The average 4D-CT was used for the treatment planning among all three modalities with identical patient contouring and treatment planning goal. A proton therapy plan was generated in XiO treatment planning system (TPS using 2 fields for each target. For a comparative purpose, IMRT and RapidArc plans were generated in Eclipse TPS. Treatment plans were generated for a total dose of 74 CGE or Gy prescribed to each planning target volume (PTV (left and right with 2 CGE or Gy per fraction. In IMRT and RapidArc plans, normalization was done based on PTV coverage values in proton plans. Results: The mean PTV dose deviation from the prescription dose was lower in proton plan (within 3.4%, but higher in IMRT (6.5% to 11.3% and RapidArc (3.8% to 11.5% plans. Proton therapy produced lower mean dose to the total lung, heart, and esophagus when compared to IMRT and RapidArc. The relative volume of the total lung receiving 20, 10, and 5 CGE or Gy (V20, V10, and V5, respectively were lower using proton therapy than using IMRT, with absolute differences of 9.71%, 22.88%, and 39.04%, respectively. The absolute differences in the V20, V10, and V5 between proton and RapidArc plans were 4.84%, 19.16%, and 36.8%, respectively, with proton therapy producing lower dosimetric values. Conclusion: Based on the results presented in this case study, uniform scanning proton therapy has a dosimetric advantage over both IMRT and RapidArc for a synchronous bi-lateral NSCLC, especially for the normal lung tissue, heart, and

  9. Acute toxicity profile of craniospinal irradiation with intensity-modulated radiation therapy in children with medulloblastoma: A prospective analysis

    International Nuclear Information System (INIS)

    Cox, Maurice C.; Kusters, Johannes M.; Gidding, Corrie E.; Schieving, Jolanda H.; Lindert, Erik J. van; Kaanders, Johannes H.; Janssens, Geert O.

    2015-01-01

    To report on the acute toxicity in children with medulloblastoma undergoing intensity-modulated radiation therapy (IMRT) with daily intrafractionally modulated junctions. Newly diagnosed patients, aged 3–21, with standard-risk (SR) or high-risk (HR) medulloblastoma were eligible. A dose of 23.4 or 36.0Gy in daily fractions of 1.8Gy was prescribed to the craniospinal axis, followed by a boost to the primary tumor bed (54 or 55.8Gy) and metastases (39.6–55.8Gy), when indicated. Weekly, an intravenous bolus of vincristine was combined for patients with SR medulloblastoma and patients participating in the COG-ACNS-0332 study. Common toxicity criteria (CTC, version 2.0) focusing on skin, alopecia, voice changes, conjunctivitis, anorexia, dysphagia, gastro-intestinal symptoms, headache, fatigue and hematological changes were scored weekly during radiotherapy. From 2010 to 2014, data from 15 consecutive patients (SR, n = 7; HR, n = 8) were collected. Within 72 h from onset of treatment, vomiting (66 %) and headache (46 %) occurred. During week 3 of treatment, a peak incidence in constipation (33 %) and abdominal pain/cramping (40 %) was observed, but only in the subgroup of patients (n = 9) receiving vincristine (constipation: 56 vs 0 %, P = .04; pain/cramping: 67 vs 0 %, P = .03). At week 6, 73 % of the patients developed faint erythema of the cranial skin with dry desquamation (40 %) or moist desquamation confined to the skin folds of the auricle (33 %). No reaction of the skin overlying the spinal target volume was observed. Headache at onset and gastro-intestinal toxicity, especially in patients receiving weekly vincristine, were the major complaints of patients with medulloblastoma undergoing craniospinal irradiation with IMRT

  10. A dosimetric comparison of 3D conformal vs intensity modulated vs volumetric arc radiation therapy for muscle invasive bladder cancer

    Directory of Open Access Journals (Sweden)

    Foroudi Farshad

    2012-07-01

    Full Text Available Abstract Background To compare 3 Dimensional Conformal radiotherapy (3D-CRT with Intensity Modulated Radiotherapy (IMRT with Volumetric-Modulated Arc Therapy (VMAT for bladder cancer. Methods Radiotherapy plans for 15 patients with T2-T4N0M0 bladder cancer were prospectively developed for 3-DCRT, IMRT and VMAT using Varian Eclipse planning system. The same radiation therapist carried out all planning and the same clinical dosimetric constraints were used. 10 of the patients with well localised tumours had a simultaneous infield boost (SIB of the primary tumour planned for both IMRT and VMAT. Tumour control probabilities and normal tissue complication probabilities were calculated. Results Mean planning time for 3D-CRT, IMRT and VMAT was 30.0, 49.3, and 141.0 minutes respectively. The mean PTV conformity (CI index for 3D-CRT was 1.32, for IMRT 1.05, and for VMAT 1.05. The PTV Homogeneity (HI index was 0.080 for 3D-CRT, 0.073 for IMRT and 0.086 for VMAT. Tumour control and normal tissue complication probabilities were similar for 3D-CRT, IMRT and VMAT. The mean monitor units were 267 (range 250–293 for 3D-CRT; 824 (range 641–1083 for IMRT; and 403 (range 333–489 for VMAT (P  Conclusions VMAT is associated with similar dosimetric advantages as IMRT over 3D-CRT for muscle invasive bladder cancer. VMAT is associated with faster delivery times and less number of mean monitor units than IMRT. SIB is feasible in selected patients with localized tumours.

  11. Xerostomia in patients treated for oropharyngeal carcinoma: comparing linear accelerator-based intensity-modulated radiation therapy with helical tomotherapy.

    Science.gov (United States)

    Fortin, Israël; Fortin, Bernard; Lambert, Louise; Clavel, Sébastien; Alizadeh, Moein; Filion, Edith J; Soulières, Denis; Bélair, Manon; Guertin, Louis; Nguyen-Tan, Phuc Felix

    2014-09-01

    In comparison to sliding-window intensity-modulated radiation therapy (sw-IMRT), we hypothesized that helical tomotherapy (HT) would achieve similar locoregional control and, at the same time, decrease the parotid gland dose, thus leading to a xerostomia reduction. The association between radiation techniques, mean parotid dose, and xerostomia incidence, was reviewed in 119 patients with advanced oropharyngeal carcinoma treated with concurrent chemoradiation using sw-IMRT (n = 59) or HT (n = 60). Ipsilateral and contralateral parotid mean doses were significantly lower for patients treated with HT versus sw-IMRT: 24 Gy versus 32 Gy ipsilaterally and 20 Gy versus 25 Gy contralaterally. The incidence of grade ≥2 xerostomia was significantly lower in the HT group than in the sw-IMRT group: 12% versus 78% at 6 months, 3% versus 51% at 12 months, and 0% versus 25% at 24 months. Total parotid mean dose xerostomia at 6, 12, and 24 months. This retrospective series suggests that using HT can better spare the parotid glands while respecting quantitative analysis of normal tissue effects in the clinic (QUANTEC)'s criteria. Copyright © 2013 Wiley Periodicals, Inc.

  12. Forward-planned intensity modulated radiation therapy using a cobalt source: A dosimetric study in breast cancer

    Directory of Open Access Journals (Sweden)

    Savino Cilla

    2013-01-01

    Full Text Available This analysis evaluates the feasibility and dosimetric results of a simplified intensity-modulated radiotherapy (IMRT treatment using a cobalt-therapy unit for post-operative breast cancer. Fourteen patients were included. Three plans per patient were produced by a cobalt-60 source: A standard plan with two wedged tangential beams, a standard tangential plan optimized without the use of wedges and a plan based on the forward-planned "field-in-field" IMRT technique (Co-FinF where the dose on each of the two tangential beams was split into two different segments and the two segments weight was determined with an iterative process. For comparison purposes, a 6-MV photon standard wedged tangential treatment plan was generated. D mean , D 98% , D 2% , V 95% , V 107%, homogeneity, and conformity indices were chosen as parameters for comparison. Co-FinF technique improved the planning target volume dose homogeneity compared to other cobalt-based techniques and reduced maximum doses (D 2% and high-dose volume (V 110% . Moreover, it showed a better lung and heart dose sparing with respect to the standard approach. The higher dose homogeneity may encourage the adoption of accelerated-hypofractionated treatments also with the cobalt sources. This approach can promote the spread of breast conservative treatment in developing countries.

  13. Treatment planning with intensity modulated particle therapy for multiple targets in stage IV non-small cell lung cancer

    Science.gov (United States)

    Anderle, Kristjan; Stroom, Joep; Vieira, Sandra; Pimentel, Nuno; Greco, Carlo; Durante, Marco; Graeff, Christian

    2018-01-01

    Intensity modulated particle therapy (IMPT) can produce highly conformal plans, but is limited in advanced lung cancer patients with multiple lesions due to motion and planning complexity. A 4D IMPT optimization including all motion states was expanded to include multiple targets, where each target (isocenter) is designated to specific field(s). Furthermore, to achieve stereotactic treatment planning objectives, target and OAR weights plus objective doses were automatically iteratively adapted. Finally, 4D doses were calculated for different motion scenarios. The results from our algorithm were compared to clinical stereotactic body radiation treatment (SBRT) plans. The study included eight patients with 24 lesions in total. Intended dose regimen for SBRT was 24 Gy in one fraction, but lower fractionated doses had to be delivered in three cases due to OAR constraints or failed plan quality assurance. The resulting IMPT treatment plans had no significant difference in target coverage compared to SBRT treatment plans. Average maximum point dose and dose to specific volume in OARs were on average 65% and 22% smaller with IMPT. IMPT could also deliver 24 Gy in one fraction in a patient where SBRT was limited due to the OAR vicinity. The developed algorithm shows the potential of IMPT in treatment of multiple moving targets in a complex geometry.

  14. A set cover approach to fast beam orientation optimization in intensity modulated radiation therapy for total marrow irradiation

    International Nuclear Information System (INIS)

    Lee, Chieh-Hsiu Jason; Aleman, Dionne M; Sharpe, Michael B

    2011-01-01

    The beam orientation optimization (BOO) problem in intensity modulated radiation therapy (IMRT) treatment planning is a nonlinear problem, and existing methods to obtain solutions to the BOO problem are time consuming due to the complex nature of the objective function and size of the solution space. These issues become even more difficult in total marrow irradiation (TMI), where many more beams must be used to cover a vastly larger treatment area than typical site-specific treatments (e.g., head-and-neck, prostate, etc). These complications result in excessively long computation times to develop IMRT treatment plans for TMI, so we attempt to develop methods that drastically reduce treatment planning time. We transform the BOO problem into the classical set cover problem (SCP) and use existing methods to solve SCP to obtain beam solutions. Although SCP is NP-Hard, our methods obtain beam solutions that result in quality treatments in minutes. We compare our approach to an integer programming solver for the SCP to illustrate the speed advantage of our approach.

  15. A set cover approach to fast beam orientation optimization in intensity modulated radiation therapy for total marrow irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chieh-Hsiu Jason; Aleman, Dionne M [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, ON M5S 3G8 (Canada); Sharpe, Michael B, E-mail: chjlee@mie.utoronto.ca, E-mail: aleman@mie.utoronto.ca, E-mail: michael.sharpe@rmp.uhn.on.ca [Princess Margaret Hospital, Department of Radiation Oncology, University of Toronto, 610 University Avenue, Toronto, ON M5G 2M9 (Canada)

    2011-09-07

    The beam orientation optimization (BOO) problem in intensity modulated radiation therapy (IMRT) treatment planning is a nonlinear problem, and existing methods to obtain solutions to the BOO problem are time consuming due to the complex nature of the objective function and size of the solution space. These issues become even more difficult in total marrow irradiation (TMI), where many more beams must be used to cover a vastly larger treatment area than typical site-specific treatments (e.g., head-and-neck, prostate, etc). These complications result in excessively long computation times to develop IMRT treatment plans for TMI, so we attempt to develop methods that drastically reduce treatment planning time. We transform the BOO problem into the classical set cover problem (SCP) and use existing methods to solve SCP to obtain beam solutions. Although SCP is NP-Hard, our methods obtain beam solutions that result in quality treatments in minutes. We compare our approach to an integer programming solver for the SCP to illustrate the speed advantage of our approach.

  16. Dosimetric comparison between helical tomotherapy and intensity-modulated radiation therapy plans for non-small cell lung cancer.

    Science.gov (United States)

    Meng, Ling-Ling; Feng, Lin-Chun; Wang, Yun-Lai; Dai, Xiang-Kun; Xie, Chuan-Bin

    2011-06-01

    Helical tomotherapy (HT) is a new image-guided intensity-modulated radiation therapy (IMRT) technique. It is reported that HT plan for non-small-cell lung cancer (NSCLC) can give better dose uniformity, dose gradients, and protection for the lung than IMRT plan. We compared the dosimetric characteristics of HT for NSCLC with those of conventional IMRT to observe the superiority of HT. There was a comparative case series comprising 10 patients with NSCLC. Computed tomographic (CT) images of delineated targets were transferred to the PrecisePlan planning system (IMRT) and Tomo planning system (HT). The prescription doses were 70 Gy/33F for the gross tumor volume (GTV) and the visible lymph nodes (GTVnd), and 60 Gy/33F for the clinical target volume (CTV) and the clinical target volume of the visible lymph nodes (CTVnd). The dose restrictions for organs at risk were as follows: the maximum dose to spinal cord ≤ 45 Gy, V20 to the total lungs 0.05). The maximum doses to the spinal cord, heart, esophagus and trachea in the HT plan were lower than those in the IMRT plan, but the differences were not statistically significant. The HT plan provids better dose uniformity, dose gradients, and protection for the organs at risk. It can reduce the high-dose radiation volume for lung and the MLD, but may deliver a larger lung volume of low-dose radiation.

  17. SU-E-T-07: 4DCT Robust Optimization for Esophageal Cancer Using Intensity Modulated Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Liao, L [Proton Therapy Center, UT MD Anderson Cancer Center, Houston, TX (United States); Department of Industrial Engineering, University of Houston, Houston, TX (United States); Yu, J; Zhu, X; Li, H; Zhang, X [Proton Therapy Center, UT MD Anderson Cancer Center, Houston, TX (United States); Li, Y [Proton Therapy Center, UT MD Anderson Cancer Center, Houston, TX (United States); Varian Medical Systems, Houston, TX (United States); Lim, G [Department of Industrial Engineering, University of Houston, Houston, TX (United States)

    2015-06-15

    Purpose: To develop a 4DCT robust optimization method to reduce the dosimetric impact from respiratory motion in intensity modulated proton therapy (IMPT) for esophageal cancer. Methods: Four esophageal cancer patients were selected for this study. The different phases of CT from a set of 4DCT were incorporated into the worst-case dose distribution robust optimization algorithm. 4DCT robust treatment plans were designed and compared with the conventional non-robust plans. Result doses were calculated on the average and maximum inhale/exhale phases of 4DCT. Dose volume histogram (DVH) band graphic and ΔD95%, ΔD98%, ΔD5%, ΔD2% of CTV between different phases were used to evaluate the robustness of the plans. Results: Compare to the IMPT plans optimized using conventional methods, the 4DCT robust IMPT plans can achieve the same quality in nominal cases, while yield a better robustness to breathing motion. The mean ΔD95%, ΔD98%, ΔD5% and ΔD2% of CTV are 6%, 3.2%, 0.9% and 1% for the robustly optimized plans vs. 16.2%, 11.8%, 1.6% and 3.3% from the conventional non-robust plans. Conclusion: A 4DCT robust optimization method was proposed for esophageal cancer using IMPT. We demonstrate that the 4DCT robust optimization can mitigate the dose deviation caused by the diaphragm motion.

  18. 3D radiation therapy or intensity-modulated radiotherapy for recurrent and metastatic cervical cancer: the Shanghai Cancer Hospital experience.

    Directory of Open Access Journals (Sweden)

    Su-Ping Liu

    Full Text Available We evaluate the outcomes of irradiation by using three-dimensional radiation therapy (3D-RT or intensity-modulated radiotherapy (IMRT for recurrent and metastatic cervical cancer. Between 2007 and 2010, 50 patients with recurrent and metastatic cervical cancer were treated using 3D-RT or IMRT. The median time interval between the initial treatment and the start of irradiation was 12 (6-51 months. Salvage surgery was performed before irradiation in 5 patients, and 38 patients received concurrent chemotherapy. Sixteen patients underwent 3D-RT, and 34 patients received IMRT. Median follow-up for all the patients was 18.3 months. Three-year overall survival and locoregional control were 56.1% and 59.7%, respectively. Three-year progression-free survival and disease-free survival were 65.3% and 64.3%, respectively. Nine patients developed grade 3 leukopenia. Grade 5 acute toxicity was not observed in any of the patients; however, 2 patients developed Grade 3 late toxicity. 3D-RT or IMRT is effective for the treatment of recurrent and metastatic cervical cancer, with the 3-year overall survival of 56.1%, and its complications are acceptable. Long-term follow-up and further studies are needed to confirm the role of 3D-RT or IMRT in the multimodality management of the disease.

  19. Prospective Study of Functional Bone Marrow-Sparing Intensity Modulated Radiation Therapy With Concurrent Chemotherapy for Pelvic Malignancies

    International Nuclear Information System (INIS)

    Liang Yun; Bydder, Mark; Yashar, Catheryn M.; Rose, Brent S.; Cornell, Mariel; Hoh, Carl K.; Lawson, Joshua D.; Einck, John; Saenz, Cheryl; Fanta, Paul; Mundt, Arno J.; Bydder, Graeme M.

    2013-01-01

    Purpose: To test the hypothesis that intensity modulated radiation therapy (IMRT) can reduce radiation dose to functional bone marrow (BM) in patients with pelvic malignancies (phase IA) and estimate the clinical feasibility and acute toxicity associated with this technique (phase IB). Methods and Materials: We enrolled 31 subjects (19 with gynecologic cancer and 12 with anal cancer) in an institutional review board-approved prospective trial (6 in the pilot study, 10 in phase IA, and 15 in phase IB). The mean age was 52 years; 8 of 31 patients (26%) were men. Twenty-one subjects completed 18 F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) simulation and magnetic resonance imaging by use of quantitative IDEAL (IDEAL IQ; GE Healthcare, Waukesha, WI). The PET/CT and IDEAL IQ were registered, and BM subvolumes were segmented above the mean standardized uptake value and below the mean fat fraction within the pelvis and lumbar spine; their intersection was designated as functional BM for IMRT planning. Functional BM-sparing vs total BM-sparing IMRT plans were compared in 12 subjects; 10 were treated with functional BM-sparing pelvic IMRT per protocol. Results: In gynecologic cancer patients, the mean functional BM V 10 (volume receiving ≥10 Gy) and V 20 (volume receiving ≥20 Gy) were 85% vs 94% (P 18 F-fluorodeoxyglucose-PET/CT and IDEAL IQ. The efficacy of BM-sparing IMRT is being tested in a phase II trial.

  20. Multi-institutional Comparison of Intensity Modulated Radiation Therapy (IMRT) Planning Strategies and Planning Results for Nasopharyngeal Cancer

    Science.gov (United States)

    Park, Sung Ho; Park, Suk Won; Oh, Do Hoon; Choi, Youngmin; Kim, Jeung Kee; Ahn, Yong Chan; Park, Won; Suh, Hyun Sook; Lee, Rena; Bae, Hoonsik

    2009-01-01

    The intensity-modulated radiation therapy (IMRT) planning strategies for nasopharyngeal cancer among Korean radiation oncology facilities were investigated. Five institutions with IMRT planning capacity using the same planning system were invited to participate in this study. The institutions were requested to produce the best plan possible for 2 cases that would deliver 70 Gy to the planning target volume of gross tumor (PTV1), 59.4 Gy to the PTV2, and 51.5 Gy to the PTV3 in which elective irradiation was required. The advised fractionation number was 33. The planning parameters, resultant dose distributions, and biological indices were compared. We found 2-3-fold variations in the volume of treatment targets. Similar degree of variation was found in the delineation of normal tissue. The physician-related factors in IMRT planning had more influence on the plan quality. The inhomogeneity index of PTV dose ranged from 4 to 49% in Case 1, and from 5 to 46% in Case 2. Variation in tumor control probabilities for the primary lesion and involved LNs was less marked. Normal tissue complication probabilities for parotid glands and skin showed marked variation. Results from this study suggest that greater efforts in providing training and continuing education in terms of IMRT planning parameters usually set by physician are necessary for the successful implementation of IMRT. PMID:19399266

  1. Intensity Modulated Radiation Therapy in Head and Neck Squamous Cell Carcinoma: state of the art and future challenges

    International Nuclear Information System (INIS)

    Gregoire, V.; Maingon, P.

    2005-01-01

    Intensity-modulated radiation therapy (IMRT) for head and neck (HN) tumors refers to a new approach to the whole treatment procedure from patient immobilization to beam delivery. Implementation of IMRT thus requires knowledge of setup uncertainties, adequate selection and delineation of target volumes based on clinical examination and optimal imaging modalities, appropriate specification and dose prescription regarding dose-volume constraints, and ad hoc quality control of both the clinical and physical aspects of the whole procedure. A large number of issues still need to be resolved and/or further refined, such as the optimal selection and delineation of the target volume in particular, with the introduction of functional imaging, and a better integration of improved dose distribution into the fractionation strategy. IMRT is associated with a potentially increased incidence of carcinogenesis, although in the HN area this risk is relative to the intrinsic risk of co-morbidity and secondary cancer associated with the patient's lifestyle. Currently, the implementation of IMRT into routine clinical practice for HN cancers may not be a straightforward matter, and should probably be restricted to selected patients and selected institutions with adequate resources and experience. This review emphasizes the above aspects and provides some recommendations for the future use of IMRT in patients with HN tumors. (author)

  2. Development and evaluation of a phantom for multi-purpose dosimetry in intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Jeong, Hae Sun; Kim, Chan Hyeong; Park, Joo Hwan; Han, Young Yih; Kum, O Yeon

    2011-01-01

    A LEGO-type multi-purpose dosimetry phantom was developed for intensity-modulated radiation therapy (IMRT), which requires various types of challenging dosimetry. Polystyrene, polyethylene, polytetrafluoroethylene (PTFE), and polyurethane foam (PU-F) were selected to represent muscle, fat, bone, and lung tissue, respectively, after considering the relevant mass densities, elemental compositions, effective atomic numbers, and photon interaction coefficients. The phantom, which is composed of numerous small pieces that are similar to LEGO blocks, provides dose and dose distribution measurements in homogeneous and heterogeneous media. The phantom includes dosimeter holders for several types of dosimeters that are frequently used in IMRT dosimetry. An ion chamber and a diode detector were used to test dosimetry in heterogeneous media under radiation fields of various sizes. The data that were measured using these dosimeters were in disagreement when the field sizes were smaller than 1.5 x 1.5 cm 2 for polystyrene and PTFE, or smaller than 3 x 3 cm 2 for an air cavity. The discrepancy was as large as 41% for the air cavity when the field size was 0.7 x 0.7 cm 2 , highlighting one of the challenges of IMRT small field dosimetry. The LEGO-type phantom is also very useful for two-dimensional dosimetry analysis, which elucidates the electronic dis-equilibrium phenomena on or near the heterogeneity boundaries

  3. Development and evaluation of a phantom for multi-purpose dosimetry in intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hae Sun; Kim, Chan Hyeong [Hanyang University, Seoul (Korea, Republic of); Park, Joo Hwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Han, Young Yih [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kum, O Yeon [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2011-08-15

    A LEGO-type multi-purpose dosimetry phantom was developed for intensity-modulated radiation therapy (IMRT), which requires various types of challenging dosimetry. Polystyrene, polyethylene, polytetrafluoroethylene (PTFE), and polyurethane foam (PU-F) were selected to represent muscle, fat, bone, and lung tissue, respectively, after considering the relevant mass densities, elemental compositions, effective atomic numbers, and photon interaction coefficients. The phantom, which is composed of numerous small pieces that are similar to LEGO blocks, provides dose and dose distribution measurements in homogeneous and heterogeneous media. The phantom includes dosimeter holders for several types of dosimeters that are frequently used in IMRT dosimetry. An ion chamber and a diode detector were used to test dosimetry in heterogeneous media under radiation fields of various sizes. The data that were measured using these dosimeters were in disagreement when the field sizes were smaller than 1.5 x 1.5 cm{sup 2} for polystyrene and PTFE, or smaller than 3 x 3 cm{sup 2} for an air cavity. The discrepancy was as large as 41% for the air cavity when the field size was 0.7 x 0.7 cm{sup 2}, highlighting one of the challenges of IMRT small field dosimetry. The LEGO-type phantom is also very useful for two-dimensional dosimetry analysis, which elucidates the electronic dis-equilibrium phenomena on or near the heterogeneity boundaries

  4. Dosimetric study of optimal beam number and arrangement for treatment of nasopharyngeal carcinoma with intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Budrukkar, Ashwini; Corry, June; Peters, Lester J.; Hope, Geoff; Cramb, Jim

    2004-01-01

    The purpose of this dosimetric study was to evaluate the effect of beam number and arrangement on the dose distribution with intensity-modulated radiation therapy in patients with nasopharyngeal cancer. Computed tomography data sets of seven patients who were treated for nasopharyngeal carcinoma at the Peter MacCallum Cancer Centre were used for the present dosimetric study. The dose planned was 70 Gy in 7 weeks for the gross nasopharyngeal and nodal disease and the biological equivalents of 60 Gy in 6 weeks for the high-risk and 50 Gy in 5 weeks for the low-risk nodal disease. A plan using seven fields was compared to that using nine fields in all patients. Plans were assessed on the dose to the planning target volume (PTV) and the degree of parotid sparing achieved by evaluating both dose-volume histograms (DVH) and axial slices. Seven fields (three anterior and four posterior) provide good PTV coverage and satisfactory parotid sparing in patients with localized nasopharyngeal lesions. Nine fields appear to be better for tumours with significant posterolateral parapharyngeal extension. Parotid sparing is consistently better with nine fields. Both DVH and axial slices need to be evaluated before accepting any plan Copyright (2004) Blackwell Publishing Asia Pty Ltd

  5. Dosimetric comparison of three intensity-modulated radiation therapies for left breast cancer after breast-conserving surgery.

    Science.gov (United States)

    Zhang, Huai-Wen; Hu, Bo; Xie, Chen; Wang, Yun-Lai

    2018-05-01

    This study aimed to evaluate dosimetric differences of intensity-modulated radiation therapy (IMRT) in target and normal tissues after breast-conserving surgery. IMRT five-field plan I, IMRT six-field plan II, and field-in-field-direct machine parameter optimization-IMRT plan III were designed for each of the 50 patients. One-way analysis of variance was performed to compare differences, and P mean dose (D mean ) for the heart (P optimization-IMRT plans III can reduce doses and volumes to the lungs and heart better while maintaining satisfying conformity index and homogeneity index of target. Nevertheless, plan II neglects target movements caused by respiration. In the same manner, plan III can substantially reduce MU and shorten patient treatment time. Therefore, plan III, which considers target movement caused by respiration, is a more practical radiation mode. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  6. Validation and application of polymer gel dosimetry for the dose verification of an intensity-modulated arc therapy (IMAT) treatment

    International Nuclear Information System (INIS)

    Vergote, K; Deene, Y de; Duthoy, W; Gersem, W de; Neve, W de; Achten, E; Wagter, C de

    2004-01-01

    Polymer gel dosimetry was used to assess an intensity-modulated arc therapy (IMAT) treatment for whole abdominopelvic radiotherapy. Prior to the actual dosimetry experiment, a uniformity study on an unirradiated anthropomorphic phantom was carried out. A correction was performed to minimize deviations in the R2 maps due to radiofrequency non-uniformities. In addition, compensation strategies were implemented to limit R2 deviations caused by temperature drift during scanning. Inter- and intra-slice R2 deviations in the phantom were thereby significantly reduced. This was verified in an investigative study where the same phantom was irradiated with two rectangular superimposed beams: structural deviations between gel measurements and computational results remained below 3% outside high dose gradient regions; the spatial shift in those regions was within 2.5 mm. When comparing gel measurements with computational results for the IMAT treatment, dose deviations were noted in the liver and right kidney, but the dose-volume constraints were met. Root-mean-square differences between both dose distributions were within 5% with spatial deviations not more than 2.5 mm. Dose fluctuations due to gantry angle discretization in the dose computation algorithm were particularly noticeable in the low-dose region

  7. Dosimetric verification for primary focal hypermetabolism of nasopharyngeal carcinoma patients treated with dynamic intensity-modulated radiation therapy.

    Science.gov (United States)

    Xin, Yong; Wang, Jia-Yang; Li, Liang; Tang, Tian-You; Liu, Gui-Hong; Wang, Jian-She; Xu, Yu-Mei; Chen, Yong; Zhang, Long-Zhen

    2012-01-01

    To make sure the feasibility with (18F)FDG PET/CT to guided dynamic intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma patients, by dosimetric verification before treatment. Chose 11 patients in III~IVA nasopharyngeal carcinoma treated with functional image-guided IMRT and absolute and relative dosimetric verification by Varian 23EX LA, ionization chamber, 2DICA of I'mRT Matrixx and IBA detachable phantom. Drawing outline and making treatment plan were by different imaging techniques (CT and (18F)FDG PET/CT). The dose distributions of the various regional were realized by SMART. The absolute mean errors of interest area were 2.39%±0.66 using 0.6 cc ice chamber. Results using DTA method, the average relative dose measurements within our protocol (3%, 3 mm) were 87.64% at 300 MU/min in all filed. Dosimetric verification before IMRT is obligatory and necessary. Ionization chamber and 2DICA of I'mRT Matrixx was the effective dosimetric verification tool for primary focal hyper metabolism in functional image-guided dynamic IMRT for nasopharyngeal carcinoma. Our preliminary evidence indicates that functional image-guided dynamic IMRT is feasible.

  8. Dosimetric properties of an amorphous silicon electronic portal imaging device for verification of dynamic intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Greer, Peter B.; Popescu, Carmen C.

    2003-01-01

    Dosimetric properties of an amorphous silicon electronic portal imaging device (EPID) for verification of dynamic intensity modulated radiation therapy (IMRT) delivery were investigated. The EPID was utilized with continuous frame-averaging during the beam delivery. Properties studied included effect of buildup, dose linearity, field size response, sampling of rapid multileaf collimator (MLC) leaf speeds, response to dose-rate fluctuations, memory effect, and reproducibility. The dependence of response on EPID calibration and a dead time in image frame acquisition occurring every 64 frames were measured. EPID measurements were also compared to ion chamber and film for open and wedged static fields and IMRT fields. The EPID was linear with dose and dose rate, and response to MLC leaf speeds up to 2.5 cm s-1 was found to be linear. A field size dependent response of up to 5% relative to d max ion-chamber measurement was found. Reproducibility was within 0.8% (1 standard deviation) for an IMRT delivery recorded at intervals over a period of one month. The dead time in frame acquisition resulted in errors in the EPID that increased with leaf speed and were over 20% for a 1 cm leaf gap moving at 1.0 cm s-1. The EPID measurements were also found to depend on the input beam profile utilized for EPID flood-field calibration. The EPID shows promise as a device for verification of IMRT, the major limitation currently being due to dead-time in frame acquisition

  9. TH-C-BRD-12: Robust Intensity Modulated Proton Therapy Plan Can Eliminate Junction Shifts for Craniospinal Irradiation

    International Nuclear Information System (INIS)

    Liao, L; Jiang, S; Li, Y; Wang, X; Li, H; Zhu, X; Sahoo, N; Gillin, M; Mahajan, A; Grosshans, D; Zhang, X; Lim, G

    2014-01-01

    Purpose: The passive scattering proton therapy (PSPT) technique is the commonly used radiotherapy technique for craniospinal irradiation (CSI). However, PSPT involves many numbers of junction shifts applied over the course of treatment to reduce the cold and hot regions caused by field mismatching. In this work, we introduced a robust planning approach to develop an optimal and clinical efficient techniques for CSI using intensity modulated proton therapy (IMPT) so that junction shifts can essentially be eliminated. Methods: The intra-fractional uncertainty, in which two overlapping fields shift in the opposite directions along the craniospinal axis, are incorporated into the robust optimization algorithm. Treatment plans with junction sizes 3,5,10,15,20,25 cm were designed and compared with the plan designed using the non-robust optimization. Robustness of the plans were evaluated based on dose profiles along the craniospinal axis for the plans applying 3 mm intra-fractional shift. The dose intra-fraction variations (DIV) at the junction are used to evaluate the robustness of the plans. Results: The DIVs are 7.9%, 6.3%, 5.0%, 3.8%, 2.8% and 2.2%, for the robustly optimized plans with junction sizes 3,5,10,15,20,25 cm. The DIV are 10% for the non-robustly optimized plans with junction size 25 cm. The dose profiles along the craniospinal axis exhibit gradual and tapered dose distribution. Using DIVs less than 5% as maximum acceptable intrafractional variation, the overlapping region can be reduced to 10 cm, leading to potential reduced number of the fields. The DIVs are less than 5% for 5 mm intra-fractional shifts with junction size 25 cm, leading to potential no-junction-shift for CSI using IMPT. Conclusion: This work is the first report of the robust optimization on CSI based on IMPT. We demonstrate that robust optimization can lead to much efficient carniospinal irradiation by eliminating the junction shifts

  10. Multi-centre experience of implementing image-guided intensity-modulated radiotherapy using the TomoTherapy platform

    International Nuclear Information System (INIS)

    Dean, J.C.; Tudor, G.S.J.; Mott, J.H.; Dunlop, P.R.; Morris, S.L.; Harron, E.C.; Christian, J.A.; Sanghera, P.; Elsworthy, M.; Burnet, N.G.

    2013-01-01

    Use of image guided (IG) intensity modulated radiotherapy (IMRT) is increasing, and helical tomotherapy provides an effective, integrated solution. Practical experience of implementation, shared at a recent UK TomoTherapy Users' meeting, may help centres introducing these techniques using TomoTherapy or other platforms. Seven centres participated, with data shared from 6, varying from 2500 - 4800 new patients per year. Case selection of patients “most likely” to benefit from IG-IMRT was managed in all centres by multi-professional groups comprising clinical oncologists, physicists, treatment planners and radiographers. Radical treatments ranged from 94% to 100%. The proportions of tumour types varied substantially: head and neck: range 0%–100% (mean of centres 50%), prostate: 3%–96% (mean of centres 28%). Head and neck cases were considered most likely to benefit from IMRT, prostate cases from IGRT, or IG-IMRT if pelvic nodes were being treated. IMRT was also selected for complex target volumes, to avoid field junctions, for technical treatment difficulties, and retreatments. Across the centres, every patient was imaged every day, with positional correction before treatment. In one centre, for prostate patients including pelvic treatment, the pelvis was also imaged weekly. All centres had designed a ‘ramp up’ of patient numbers, which was similar in 5. One centre, treating 96% prostate patients, started with 3 and increased to 36 patients per day within 3 months. The variation in case mix implies wide applicability of IG-IMRT. Daily on-line IGRT with IMRT can be routinely implemented into busy departments

  11. Evaluation of Kodak EDR2 film for dose verification of intensity modulated radiation therapy delivered by a static multileaf collimator.

    Science.gov (United States)

    Zhu, X R; Jursinic, P A; Grimm, D F; Lopez, F; Rownd, J J; Gillin, M T

    2002-08-01

    A new type of radiographic film, Kodak EDR2 film, was evaluated for dose verification of intensity modulated radiation therapy (IMRT) delivered by a static multileaf collimator (SMLC). A sensitometric curve of EDR2 film irradiated by a 6 MV x-ray beam was compared with that of Kodak X-OMAT V (XV) film. The effects of field size, depth and dose rate on the sensitometric curve were also studied. It is found that EDR2 film is much less sensitive than XV film. In high-energy x-ray beams, the double hit process is the dominant mechanism that renders the grains on EDR2 films developable. As a result, in the dose range that is commonly used for film dosimetry for IMRT and conventional external beam therapy, the sensitometric curves of EDR2 films cannot be approximated as a linear function, OD = c * D. Within experimental uncertainty, the film sensitivity does not depend on the dose rate (50 vs 300 MU/min) or dose per pulse (from 1.0 x 10(-4) to 4.21 x 10(-4) Gy/pulse). Field sizes and depths (up to field size of 10 x 10 cm2 and depth = 10 cm) have little effect on the sensitometric curves. Percent depth doses (PDDs) for both 6 and 23 MV x rays were measured with both EDR2 and XV films and compared with ion chamber data. Film data are within 2.5% of the ion chamber results. Dose profiles measured with EDR2 film are consistent with those measured with an ion chamber. Examples of measured IMRT isodose distributions versus calculated isodoses are presented. We have used EDR2 films for verification of all IMRT patients treated by SMLC in our clinic. In most cases, with EDR2 film, actual clinical daily fraction doses can be used for verification of composite isodose distributions of SMLC-based IMRT.

  12. A national survey of the availability of intensity-modulated radiation therapy and stereotactic radiosurgery in Canada

    International Nuclear Information System (INIS)

    AlDuhaiby, Eman Z; Breen, Stephen; Bissonnette, Jean-Pierre; Sharpe, Michael; Mayhew, Linda; Tyldesley, Scott; Wilke, Derek R; Hodgson, David C

    2012-01-01

    The timely and appropriate adoption of new radiation therapy (RT) technologies is a challenge both in terms of providing of optimal patient care and managing health care resources. Relatively little is known regarding the rate at which new RT technologies are adopted in different jurisdictions, and the barriers to implementation of these technologies. Surveys were sent to all radiation oncology department heads in Canada regarding the availability of RT equipment from 2006 to 2010. Data were collected concerning the availability and use of Intensity Modulated Radiation Therapy (IMRT) and stereotactic radiosurgery (SRS), and the obstacles to implementation of these technologies. IMRT was available in 37% of responding centers in 2006, increasing to 87% in 2010. In 2010, 72% of centers reported that IMRT was available for all patients who might benefit, and 37% indicated that they used IMRT for 'virtually all' head and neck patients. SRS availability increased from 26% in 2006 to 42.5% in 2010. Eighty-two percent of centers reported that patients had access to SRS either directly or by referral. The main barriers for IMRT implementation included the need to train or hire treatment planning staff, whereas barriers to SRS implementation mostly included the need to purchase and/or upgrade existing planning software and equipment. The survey showed a growing adoption of IMRT and SRS in Canada, although the latter was available in less than half of responding centers. Barriers to implementation differed for IMRT compared to SRS. Enhancing human resources is an important consideration in the implementation of new RT technologies, due to the multidisciplinary nature of the planning and treatment process

  13. Multicriteria Optimization in Intensity-Modulated Radiation Therapy Treatment Planning for Locally Advanced Cancer of the Pancreatic Head

    International Nuclear Information System (INIS)

    Hong, Theodore S.; Craft, David L.; Carlsson, Fredrik; Bortfeld, Thomas R.

    2008-01-01

    Purpose: Intensity-modulated radiation therapy (IMRT) affords the potential to decrease radiation therapy-associated toxicity by creating highly conformal dose distributions. However, the inverse planning process can create a suboptimal plan despite meeting all constraints. Multicriteria optimization (MCO) may reduce the time-consuming iteration loop necessary to develop a satisfactory plan while providing information regarding trade-offs between different treatment planning goals. In this exploratory study, we examine the feasibility and utility of MCO in physician plan selection in patients with locally advanced pancreatic cancer (LAPC). Methods and Materials: The first 10 consecutive patients with LAPC treated with IMRT were evaluated. A database of plans (Pareto surface) was created that met the inverse planning goals. The physician then navigated to an 'optimal' plan from the point on the Pareto surface at which kidney dose was minimized. Results: Pareto surfaces were created for all 10 patients. A physician was able to select a plan from the Pareto surface within 10 minutes for all cases. Compared with the original (treated) IMRT plans, the plan selected from the Pareto surface had a lower stomach mean dose in 9 of 10 patients, although often at the expense of higher kidney dose than with the treated plan. Conclusion: The MCO is feasible in patients with LAPC and allows the physician to choose a satisfactory plan quickly. Generally, when given the opportunity, the physician will choose a plan with a lower stomach dose. The MCO enables a physician to provide greater active clinical input into the IMRT planning process

  14. Influence of Parotid from Various Dose Rate in Intensity Modulated Radiation Therapy Planning for Head and Neck Cancer

    International Nuclear Information System (INIS)

    Hong, Joo Wan; Jeong, Yun Ju; Won, Hui Su; Chang, Nam Jun; Choi, Ji Hun; Seok, Jin Yong

    2010-01-01

    There are various beam parameter in intensity modulated radiation therapy (IMRT). The aim of this study is to investigate how various dose rate affect the parotid in treatment plan of IMRT. Materials and Methods: The study was performed on 10 nasopharyngeal carcinoma patients who have undergone IMRT. CT images were scanned 3 mm of thickness in the same condition and the treatment plan was performed by Eclipse (Ver.7.1, Varian, Palo Alto, USA). The parameters for planning used 6 MV energy and 8 beams under the same dose volume constraint. The variation of dose rates were used 300, 400, 500 MU/min. The mean dose of both parotid was accessed from the calculated planning among the 10 patients. The mean dose of parotid was verificated by 2D diode array (Mapcheck from Sun Nuclear Corporation, Melbourne, Florida). Also, Total monitor unit (MU) and beam-on time was analysed. Results: According to the dose rate, the mean dose of parotid was increased by 0.8%, 2.0% each, when dose rate was changed from 300 MU/min to 400, 500 MU/min, moreover Total MU was increased by 5.4% and 10.6% each. There was also a dose upward trend in the dose measurement of parotid by 2D diode array. However, beam - on time difference of 1-2 minutes was no significant in the dose rate increases. From this study, when the dose rates increase, there was a significant increase of Total MU and the parotid dose accordingly, however the shortened treatment time was not significant. Hence, it is considered that there is a significant decrease of late side effect in parotid radiation therapy, if the precise dose rate in IMRT is used.

  15. Helical Tomotherapy Versus Single-Arc Intensity-Modulated Arc Therapy: A Collaborative Dosimetric Comparison Between Two Institutions

    International Nuclear Information System (INIS)

    Rong Yi; Tang, Grace; Welsh, James S.; Mohiuddin, Majid M.; Paliwal, Bhudatt; Yu, Cedric X.

    2011-01-01

    Purpose: Both helical tomotherapy (HT) and single-arc intensity-modulated arc therapy (IMAT) deliver radiation using rotational beams with multileaf collimators. We report a dual-institution study comparing dosimetric aspects of these two modalities. Methods and Materials: Eight patients each were selected from the University of Maryland (UMM) and the University of Wisconsin Cancer Center Riverview (UWR), for a total of 16 cases. Four cancer sites including brain, head and neck (HN), lung, and prostate were selected. Single-arc IMAT plans were generated at UMM using Varian RapidArc (RA), and HT plans were generated at UWR using Hi-Art II TomoTherapy. All 16 cases were planned based on the identical anatomic contours, prescriptions, and planning objectives. All plans were swapped for analysis at the same time after final approval. Dose indices for targets and critical organs were compared based on dose-volume histograms, the beam-on time, monitor units, and estimated leakage dose. After the disclosure of comparison results, replanning was done for both techniques to minimize diversity in optimization focus from different operators. Results: For the 16 cases compared, the average beam-on time was 1.4 minutes for RA and 4.8 minutes for HT plans. HT provided better target dose homogeneity (7.6% for RA and 4.2% for HT) with a lower maximum dose (110% for RA and 105% for HT). Dose conformation numbers were comparable, with RA being superior to HT (0.67 vs. 0.60). The doses to normal tissues using these two techniques were comparable, with HT showing lower doses for more critical structures. After planning comparison results were exchanged, both techniques demonstrated improvements in dose distributions or treatment delivery times. Conclusions: Both techniques created highly conformal plans that met or exceeded the planning goals. The delivery time and total monitor units were lower in RA than in HT plans, whereas HT provided higher target dose uniformity.

  16. Ototoxicity evaluation in medulloblastoma patients treated with involved field boost using intensity-modulated radiation therapy (IMRT): a retrospective review

    International Nuclear Information System (INIS)

    Vieira, Wilson Albieri; Nadalin, Wladimir; Odone Filho, Vicente; Petrilli, Antonio Sergio; Weltman, Eduardo; Chen, Michael Jenwei; Silva, Nasjla Saba da; Cappellano, Andrea Maria; Pereira, Liliane Desgualdo; Gonçalves, Maria Ines Rabelo; Ferrigno, Robson; Hanriot, Rodrigo Morais

    2014-01-01

    Ototoxicity is a known side effect of combined radiation therapy and cisplatin chemotherapy for the treatment of medulloblastoma. The delivery of an involved field boost by intensity modulated radiation therapy (IMRT) may reduce the dose to the inner ear when compared with conventional radiotherapy. The dose of cisplatin may also affect the risk of ototoxicity. A retrospective study was performed to evaluate the impact of involved field boost using IMRT and cisplatin dose on the rate of ototoxicity. Data from 41 medulloblastoma patients treated with IMRT were collected. Overall and disease-free survival rates were calculated by Kaplan-Meier method Hearing function was graded according to toxicity criteria of Pediatric Oncology Group (POG). Doses to inner ear and total cisplatin dose were correlated with hearing function by univariate and multivariate data analysis. After a mean follow-up of 44 months (range: 14 to 72 months), 37 patients remained alive, with two recurrences, both in spine with CSF involvement, resulting in a disease free-survival and overall survival of 85.2% and 90.2%, respectively. Seven patients (17%) experienced POG Grade 3 or 4 toxicity. Cisplatin dose was a significant factor for hearing loss in univariate analysis (p < 0.03). In multivariate analysis, median dose to inner ear was significantly associated with hearing loss (p < 0.01). POG grade 3 and 4 toxicity were uncommon with median doses to the inner ear bellow 42 Gy (p < 0.05) and total cisplatin dose of less than 375 mg/m 2 (p < 0.01). IMRT leads to a low rate of severe ototoxicity. Median radiation dose to auditory apparatus should be kept below 42 Gy. Cisplatin doses should not exceed 375 mg/m 2

  17. Comparison of conformal and intensity modulated radiation therapy techniques for treatment of pelvic tumors. Analysis of acute toxicity

    International Nuclear Information System (INIS)

    Ferrigno, Robson; Santos, Adriana; Martins, Lidiane C; Weltman, Eduardo; Chen, Michael J; Sakuraba, Roberto; Lopes, Cleverson P; Cruz, José C

    2010-01-01

    This retrospective analysis reports on the comparative outcome of acute gastrointestinal (GI) and genitourinary (GU) toxicities between conformal radiation therapy (CRT) and intensity modulated radiation therapy (IMRT) techniques in the treatment of patients with pelvic tumors. From January 2002 to December 2008, 69 patients with pelvic tumors underwent whole pelvic CRT and 65 underwent whole pelvic IMRT to treat pelvic lymph nodes and primary tumor regions. Total dose to the whole pelvis ranged from 50 to 50.4 Gy in 25 to 28 daily fractions. Chemotherapy (CT) regimen, when employed, was based upon primary tumor. Acute GI and GU toxicities were graded by RTOG/EORTC acute radiation morbidity criteria. Absence of GI symptoms during radiotherapy (grade 0) was more frequently observed in the IMRT group (43.1% versus 8.7; p < 0.001) and medication for diarrhea (Grade 2) was more frequently used in the CRT group (65.2% versus 38.5%; p = 0.002). Acute GI grade 1 and 3 side effects incidence was similar in both groups (18.5% versus 18.8%; p = 0.95 and 0% versus 7.2%; p = 0.058, respectively). Incidence of GU toxicity was similar in both groups (grade 0: 61.5% versus 66.6%, p = 0.54; grade 1: 20% versus 8.7%, p = 0.06; grade 2: 18.5% versus 23.5%, p = 0.50 and grade 3: 0% versus 1.5%, p > 0.99). This comparative case series shows less grade 2 acute GI toxicity in patients treated with whole pelvic IMRT in comparison with those treated with CRT. Incidence of acute GU toxicity was similar in both groups

  18. Predictors of Radiation Pneumonitis in Patients Receiving Intensity Modulated Radiation Therapy for Hodgkin and Non-Hodgkin Lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Pinnix, Chelsea C., E-mail: ccpinnix@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Smith, Grace L.; Milgrom, Sarah; Osborne, Eleanor M.; Reddy, Jay P.; Akhtari, Mani; Reed, Valerie; Arzu, Isidora; Allen, Pamela K.; Wogan, Christine F. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Fanale, Michele A.; Oki, Yasuhiro; Turturro, Francesco; Romaguera, Jorge; Fayad, Luis; Fowler, Nathan; Westin, Jason; Nastoupil, Loretta; Hagemeister, Fredrick B.; Rodriguez, M. Alma [Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); and others

    2015-05-01

    Purpose: Few studies to date have evaluated factors associated with the development of radiation pneumonitis (RP) in patients with Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL), especially in patients treated with contemporary radiation techniques. These patients represent a unique group owing to the often large radiation target volumes within the mediastinum and to the potential to receive several lines of chemotherapy that add to pulmonary toxicity for relapsed or refractory disease. Our objective was to determine the incidence and clinical and dosimetric risk factors associated with RP in lymphoma patients treated with intensity modulated radiation therapy (IMRT) at a single institution. Methods and Materials: We retrospectively reviewed clinical charts and radiation records of 150 consecutive patients who received mediastinal IMRT for HL and NHL from 2009 through 2013. Clinical and dosimetric predictors associated with RP according to Radiation Therapy Oncology Group (RTOG) acute toxicity criteria were identified in univariate analysis using the Pearson χ{sup 2} test and logistic multivariate regression. Results: Mediastinal radiation was administered as consolidation therapy in 110 patients with newly diagnosed HL or NHL and in 40 patients with relapsed or refractory disease. The overall incidence of RP (RTOG grades 1-3) was 14% in the entire cohort. Risk of RP was increased for patients who received radiation for relapsed or refractory disease (25%) versus those who received consolidation therapy (10%, P=.019). Several dosimetric parameters predicted RP, including mean lung dose of >13.5 Gy, V{sub 20} of >30%, V{sub 15} of >35%, V{sub 10} of >40%, and V{sub 5} of >55%. The likelihood ratio χ{sup 2} value was highest for V{sub 5} >55% (χ{sup 2} = 19.37). Conclusions: In using IMRT to treat mediastinal lymphoma, all dosimetric parameters predicted RP, although small doses to large volumes of lung had the greatest influence. Patients with relapsed

  19. Dosimetric performance of an enhanced dose range radiographic film for intensity-modulated radiation therapy quality assurance

    International Nuclear Information System (INIS)

    Olch, Arthur J.

    2002-01-01

    Film-based quality assurance (QA) is an important element of any intensity modulated radiation therapy (IMRT) program. XV2 film is often used for IMRT QA, however, it has saturation and energy response limitations which hinder accurate film dosimetry. A new commercially released ready-pack film has been introduced that has an extended dose range (EDR2), reportedly allowing measured doses above 600 cGy without saturation. Also, this film may have less energy dependence due to its composition. The purpose of this paper is to study and compare the two types of film with respect to absolute dose accuracy for IMRT plans, percent depth dose accuracy for square fields between 2 and 20 cm, ability to measure composite plan isodoses and single beam fluence maps for IMRT cases, and sensitivity to processor variations over time. In 19 IMRT patient QA tests, the EDR2 film was able to achieve an absolute dose accuracy of better than 2% vs over 4% for XV2 film. The EDR2 film was able to reproduce ionization chamber and diode-measured percent depth doses to 20 cm depth generally to within 1% over the range of field sizes tested compared to about 10% for the XV2 film. When compared to calculations, EDR2 film agreed better than XV2 film for both composite plan isodoses and single beam fluence intensity maps. The EDR2 film was somewhat more resistant to processor changes over time than the XV2 film, with a standard deviation of dose reproducibility of less than 2% compared to 6%, respectively

  20. Intensity modulated radiation therapy for oropharyngeal cancer: the sensitivity of plan objectives and constraints to set-up uncertainty

    International Nuclear Information System (INIS)

    Ploquin, Nicolas; Song, William; Lau, Harold; Dunscombe, Peter

    2005-01-01

    The goal of this study was to assess the impact of set-up uncertainty on compliance with the objectives and constraints of an intensity modulated radiation therapy protocol for early stage cancer of the oropharynx. As the convolution approach to the quantitative study of set-up uncertainties cannot accommodate either surface contours or internal inhomogeneities, both of which are highly relevant to sites in the head and neck, we have employed the more resource intensive direct simulation method. The impact of both systematic (variable from 0 to 6 mm) and random (fixed at 2 mm) set-up uncertainties on compliance with the criteria of the RTOG H-0022 protocol has been examined for eight geometrically complex structures: CTV66 (gross tumour volume and palpable lymph nodes suspicious for metastases), CTV54 (lymph node groups or surgical neck levels at risk of subclinical metastases), glottic larynx, spinal cord, brainstem, mandible and left and right parotids. In a probability-based approach, both dose-volume histograms and equivalent uniform doses were used to describe the dose distributions achieved by plans for two patients, in the presence of set-up uncertainty. The equivalent uniform dose is defined to be that dose which, when delivered uniformly to the organ of interest, will lead to the same response as the non-uniform dose under consideration. For systematic set-up uncertainties greater than 2 mm and 5 mm respectively, coverage of the CTV66 and CTV54 could be significantly compromised. Directional sensitivity was observed in both cases. Most organs at risk (except the glottic larynx which did not comply under static conditions) continued to meet the dose constraints up to 4 mm systematic uncertainty for both plans. The exception was the contra lateral parotid gland, which this protocol is specifically designed to protect. Sensitivity to systematic set-up uncertainty of 2 mm was observed for this organ at risk in both clinical plans

  1. The GLAaS algorithm for portal dosimetry and quality assurance of RapidArc, an intensity modulated rotational therapy

    International Nuclear Information System (INIS)

    Nicolini, Giorgia; Vanetti, Eugenio; Clivio, Alessandro; Fogliata, Antonella; Korreman, Stine; Bocanek, Jiri; Cozzi, Luca

    2008-01-01

    To expand and test the dosimetric procedure, known as GLAaS, for amorphous silicon detectors to the RapidArc intensity modulated arc delivery with Varian infrastructures and to test the RapidArc dosimetric reliability between calculation and delivery. The GLAaS algorithm was applied and tested on a set of RapidArc fields at both low (6 MV) and high (18 MV) beam energies with a PV-aS1000 detector. Pilot tests for short arcs were performed on a 6 MV beam associated to a PV-aS500. RapidArc is a novel planning and delivery method in the category of intensity modulated arc therapies aiming to deliver highly modulated plans with variable MLC shapes, dose rate and gantry speed during rotation. Tests were repeated for entire (360 degrees) gantry rotations on composite dose plans and for short partial arcs (of ~6 or 12 degrees) to assess GLAaS and RapidArc mutual relationships on global and fine delivery scales. The gamma index concept of Low and the Modulation Index concept of Webb were applied to compare quantitatively TPS dose matrices and dose converted PV images. The Gamma Agreement Index computed for a Distance to Agreement of 3 mm and a Dose Difference (ΔD) of 3% was, as mean ± 1 SD, 96.7 ± 1.2% at 6 MV and 94.9 ± 1.3% at 18 MV, over the field area. These findings deteriorated slightly is ΔD was reduced to 2% (93.4 ± 3.2% and 90.1 ± 3.1%, respectively) and improved with ΔD = 4% (98.3 ± 0.8% and 97.3 ± 0.9%, respectively). For all tests a grid of 1 mm and the AAA photon dose calculation algorithm were applied. The spatial resolution of the PV-aS1000 is 0.392 mm/pxl. The Modulation Index for calculations resulted 17.0 ± 3.2 at 6 MV and 15.3 ± 2.7 at 18 MV while the corresponding data for measurements were: 18.5 ± 3.7 and 17.5 ± 3.7. Partial arcs findings were (for ΔD = 3%): GAI = 96.7 ± 0.9% for 6° rotations and 98.0 ± 1.1% for 12° rotations. The GLAaS method can be considered as a valid Quality Assurance tool for the verification of RapidArc fields

  2. Intensity modulated radiation therapy: Analysis of patient specific quality control results, experience of Rene-Gauducheau Centre

    International Nuclear Information System (INIS)

    Chiavassa, S.; Brunet, G.; Gaudaire, S.; Munos-Llagostera, C.; Delpon, G.; Lisbona, A.

    2011-01-01

    Purpose. - Systematic verifications of patient's specific intensity-modulated radiation treatments are usually performed with absolute and relative measurements. The results constitute a database which allows the identification of potential systematic errors. Material and methods. - We analyzed 1270 beams distributed in 232 treatment plans. Step-and-shoot intensity-modulated radiation treatments were performed with a Clinac (6 and 23 MV) and sliding window intensity-modulated radiation treatments with a Novalis (6 MV). Results. - The distributions obtained do not show systematic error and all the control meet specified tolerances. Conclusion. - These results allow us to reduce controls specific patients for treatments performed under identical conditions (location, optimization and segmentation parameters of treatment planning system, etc.). (authors)

  3. Dosimetric comparison between step-shoot intensity-modulated radiotherapy and volumetric-modulated arc therapy for upper thoracic and cervical esophageal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Min; Li, Qilin; Ning, Zhonghua; Gu, Wendong; Huang, Jin; Mu, Jinming; Pei, Honglei, E-mail: hongleipei@126.com

    2016-07-01

    To compare and analyze the dosimetric characteristics of volumetric modulated arc therapy (VMAT) vs step-shoot intensity-modulated radiation therapy (sIMRT) for upper thoracic and cervical esophageal carcinoma. Single-arc VMAT (VMAT1), dual-arc VMAT (VMAT2), and 7-field sIMRT plans were designed for 30 patients with upper thoracic or cervical esophageal carcinoma. Planning target volume (PTV) was prescribed to 50.4 Gy in 28 fractions, and PTV1 was prescribed to 60 Gy in 28 fractions. The parameters evaluated included dose homogeneity and conformality, dose to organs at risk (OARs), and delivery efficiency. (1) In comparison to sIMRT, VMAT provided a systematic improvement in PTV1 coverage. The homogeneity index of VMAT1 was better than that of VMAT2. There were no significant differences among sIMRT, VMAT1, and VMAT2 in PTV coverage. (2) VMAT1 and VMAT2 reduced the maximum dose of spinal cord as compared with sIMRT (p < 0.05). The rest dose-volume characteristics of OARs were similar. (3) Monitor units of VMAT2 and VMAT1 were more than sIMRT. However, the treatment time of VMAT1, VMAT2, and sIMRT was (2.0 ± 0.2), (2.8 ± 0.3), and (9.8 ± 0.8) minutes, respectively. VMAT1 was the fastest, and the difference was statistically significant. In the treatment of upper thoracic and cervical esophageal carcinoma by the AXESSE linac, compared with 7-field sIMRT, VMAT showed better PTV1 coverage and superior spinal cord sparing. Single-arc VMAT had similar target volume coverage and the sparing of OAR to dual-arc VMAT, with shortest treatment time and highest treatment efficiency in the 3 kinds of plans.

  4. SU-E-T-166: Evaluation of Integral Dose in Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy for Head and Neck Cancer Patient

    Energy Technology Data Exchange (ETDEWEB)

    Al-Basheer, A; Hunag, J; Kaminski, J; Dasher, B; Howington, J; Stewart, J; Martin, D; Kong, F; Jin, J [Georgia Regents University, Augusta, GA (Georgia)

    2014-06-01

    Purpose: Volumetric Modulated Arc Therapy (VMAT) usually achieves higher conformity of radiation doses to targets and less delivery time than Intensity Modulated Radiation Therapy (IMRT). We hypothesized that VMAT will increase integral dose (ID) to patients which will decrease the count of white blood count (WBC) lymphocytes, and consequently has a subsequent impact on the immune system. The purpose of this study is to evaluate the ID to patients undergoing IMRT and VMAT for Head and Neck cancers and its impact on the immune system. Methods: As a pilot study, 30 head and neck patients who received 9-fields IMRT or 3-arcs Radip-Arcbased VMAT were included in this study. Ten of these patients who received the VMAT plans were re-planned using IMRT with the same objectives. ID was calculated for all cases. All patients also had a baseline WBC obtained prior to treatment, and 3 sets of labs drawn during the course of radiation treatment. Results: For the 10 re-planned patients, the mean ID was 13.3 Gy/voxel (range 10.2–17.5 Gy/voxel) for the 9-fields IMRT plans, and was 15.9 Gy/voxel (range 12.4-20.9 Gy/voxel) for the 3-Arc VMAT plan (p=0.01). The integral dose was significant correlated with reducing WBC count during RT even when controlling for concurrent chemotherapy (R square =0.56, p=0.008). Conclusion: Although VMAT can deliver higher radiation dose conformality to targets, this benefit is achieved generally at the cost of greater integral doses to normal tissue outside the planning target volume (PTV). Lower WBC counts during RT were associated with higher Integral doses even when controlling for concurrent chemotherapy. This study is ongoing in our Institution to exam the impact of integral doses and WBC on overall survival.

  5. A Phase II Study of Intensity Modulated Radiation Therapy to the Pelvis for Postoperative Patients With Endometrial Carcinoma: Radiation Therapy Oncology Group Trial 0418

    Energy Technology Data Exchange (ETDEWEB)

    Jhingran, Anuja, E-mail: ajhingra@mdanderson.org [University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Winter, Kathryn [RTOG Statistical Center, Philadelphia, Pennsylvania (United States); Portelance, Lorraine [University of Miami, Miami, Florida (United States); Miller, Brigitte [Carolinas Medical Center North East, Concord, North Carolina (United States); Salehpour, Mohammad [University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gaur, Rakesh [St. Luke' s Hospital, Kansas City, Missouri (United States); Souhami, Luis [McGill University Health Centre, Montreal, Quebec (Canada); Small, William [Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, Illionis (United States); Berk, Lawrence [H. Lee Moffitt Cancer Center, Tampa, Florida (United States); Gaffney, David [Huntsman Cancer Hospital, Salt Lake City, Utah (United States)

    2012-09-01

    Purpose: To determine the feasibility of pelvic intensity modulated radiation therapy (IMRT) for patients with endometrial cancer in a multi-institutional setting and to determine whether this treatment is associated with fewer short-term bowel adverse events than standard radiation therapy. Methods: Patients with adenocarcinoma of the endometrium treated with pelvic radiation therapy alone were eligible. Guidelines for target definition and delineation, dose prescription, and dose-volume constraints for the targets and critical normal structures were detailed in the study protocol and a web-based atlas. Results: Fifty-eight patients were accrued by 25 institutions; 43 were eligible for analysis. Forty-two patients (98%) had an acceptable IMRT plan; 1 had an unacceptable variation from the prescribed dose to the nodal planning target volume. The proportions of cases in which doses to critical normal structures exceeded protocol criteria were as follows: bladder, 67%; rectum, 76%; bowel, 17%; and femoral heads, 33%. Twelve patients (28%) developed grade {>=}2 short-term bowel adverse events. Conclusions: Pelvic IMRT for endometrial cancer is feasible across multiple institutions with use of a detailed protocol and centralized quality assurance (QA). For future trials, contouring of vaginal and nodal tissue will need continued monitoring with good QA and better definitions will be needed for organs at risk.

  6. Dose to radiation therapists from activation at high-energy accelerators used for conventional and intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Rawlinson, J. Alan; Islam, Mohammad K.; Galbraith, Duncan M.

    2002-01-01

    The increased beam-on times which characterize intensity-modulated radiation therapy (IMRT) could lead to an increase in the dose received by radiation therapists due to induced activity. To examine this, gamma ray spectrometry was used to identify the major isotopes responsible for activation at a representative location in the treatment room of an 18 MV accelerator (Varian Clinac 21EX). These were found to be 28 Al, 56 Mn, and 24 Na. The decay of the dose rate measured at this location following irradiation was analyzed in terms of the known half-lives to yield saturation dose rates of 9.6, 12.4, and 6.2 μSv/h, respectively. A formalism was developed to estimate activation dose (μSv/week) due to successive patient irradiation cycles, characterized by the number of 18 MV fractions per week, F, the number of MU per fraction, M, the in-room time between fractions, t d (min), and the treatment delivery time t r ' (min). The results are represented by the sum of two formulas, one for the dose from 28 Al≅1.8x10 -3 F M (1-e -0.3t r ' )/t r ' and one for the dose from the other isotopes ≅1.1x10 -6 F 1.7 Mt d . For conventional therapy doses are about 60 μ Sv/week for an 18 MV workload of 60 000 MU/week. Irradiation for QA purposes can significantly increase the dose. For IMRT as currently practiced, lengthy treatment delivery times limit the number of fractions that can be delivered per week and hence limit the dose to values similar to those in conventional therapy. However for an IMRT regime designed to maximize patient throughput, doses up to 330 μSv/week could be expected. To reduce dose it is recommended that IMRT treatments should be delivered at energies lower than 18 MV, that in multienergy IMRT, high-energy treatments should be scheduled in the latter part of the day, and that equipment manufacturers should strive to minimize activation in the design of high-energy accelerators

  7. Aperture modulated arc therapy

    International Nuclear Information System (INIS)

    Crooks, S M; Wu, Xiaodong; Takita, C; Watzich, M; Xing Lei

    2003-01-01

    We show that it is possible to translate an intensity modulated radiation therapy (IMRT) treatment plan and deliver it as a single arc. This technique is referred to in this paper as aperture modulation arc therapy (AMAT). During this arc, the MLC leaves do not conform to the projection of the target PTV and the machine output of the accelerator has a constant value. Dose was calculated using the CORVUS 4.0 IMRT system, which uses a pencil beam dose algorithm, and treatments were delivered using a Varian 2100C/D Clinac. Results are presented for a head and neck and a prostate case, showing the equivalence of the IMRT and the translated AMAT delivery. For a prostate AMAT delivery, coronal plane film dose for the IMRT and AMAT deliveries agreed within 7.19 ± 6.62%. For a meningioma the coronal plane dose distributions were similar to a value of 4.6 ± 6.62%. Dose to the isocentre was measured as being within 2% of the planned value in both cases

  8. Impact of Multileaf Collimator Configuration Parameters on the Dosimetric Accuracy of 6-MV Intensity-Modulated Radiation Therapy Treatment Plans.

    Science.gov (United States)

    Petersen, Nick; Perrin, David; Newhauser, Wayne; Zhang, Rui

    2017-01-01

    The purpose of this study was to evaluate the impact of selected configuration parameters that govern multileaf collimator (MLC) transmission and rounded leaf offset in a commercial treatment planning system (TPS) (Pinnacle 3 , Philips Medical Systems, Andover, MA, USA) on the accuracy of intensity-modulated radiation therapy (IMRT) dose calculation. The MLC leaf transmission factor was modified based on measurements made with ionization chambers. The table of parameters containing rounded-leaf-end offset values was modified by measuring the radiation field edge as a function of leaf bank position with an ionization chamber in a scanning water-tank dosimetry system and comparing the locations to those predicted by the TPS. The modified parameter values were validated by performing IMRT quality assurance (QA) measurements on 19 gantry-static IMRT plans. Planar dose measurements were performed with radiographic film and a diode array (MapCHECK2) and compared to TPS calculated dose distributions using default and modified configuration parameters. Based on measurements, the leaf transmission factor was changed from a default value of 0.001 to 0.005. Surprisingly, this modification resulted in a small but statistically significant worsening of IMRT QA gamma-index passing rate, which revealed that the overall dosimetric accuracy of the TPS depends on multiple configuration parameters in a manner that is coupled and not intuitive because of the commissioning protocol used in our clinic. The rounded leaf offset table had little room for improvement, with the average difference between the default and modified offset values being -0.2 ± 0.7 mm. While our results depend on the current clinical protocols, treatment unit and TPS used, the methodology used in this study is generally applicable. Different clinics could potentially obtain different results and improve their dosimetric accuracy using our approach.

  9. Impact of multileaf collimator configuration parameters on the dosimetric accuracy of 6-MV Intensity-Modulated radiation therapy treatment plans

    Directory of Open Access Journals (Sweden)

    Nick Petersen

    2017-01-01

    Full Text Available The purpose of this study was to evaluate the impact of selected configuration parameters that govern multileaf collimator (MLC transmission and rounded leaf offset in a commercial treatment planning system (TPS (Pinnacle3, Philips Medical Systems, Andover, MA, USA on the accuracy of intensity-modulated radiation therapy (IMRT dose calculation. The MLC leaf transmission factor was modified based on measurements made with ionization chambers. The table of parameters containing rounded-leaf-end offset values was modified by measuring the radiation field edge as a function of leaf bank position with an ionization chamber in a scanning water-tank dosimetry system and comparing the locations to those predicted by the TPS. The modified parameter values were validated by performing IMRT quality assurance (QA measurements on 19 gantry-static IMRT plans. Planar dose measurements were performed with radiographic film and a diode array (MapCHECK2 and compared to TPS calculated dose distributions using default and modified configuration parameters. Based on measurements, the leaf transmission factor was changed from a default value of 0.001 to 0.005. Surprisingly, this modification resulted in a small but statistically significant worsening of IMRT QA gamma-index passing rate, which revealed that the overall dosimetric accuracy of the TPS depends on multiple configuration parameters in a manner that is coupled and not intuitive because of the commissioning protocol used in our clinic. The rounded leaf offset table had little room for improvement, with the average difference between the default and modified offset values being −0.2 ± 0.7 mm. While our results depend on the current clinical protocols, treatment unit and TPS used, the methodology used in this study is generally applicable. Different clinics could potentially obtain different results and improve their dosimetric accuracy using our approach.

  10. Using a Reduced Spot Size for Intensity-Modulated Proton Therapy Potentially Improves Salivary Gland-Sparing in Oropharyngeal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Water, Tara A. van de, E-mail: t.a.van.de.water@rt.umcg.nl [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Lomax, Antony J. [Centre for Proton Therapy, Paul Scherrer Institute, Villigen-PSI (Switzerland); Bijl, Hendrik P.; Schilstra, Cornelis [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Hug, Eugen B. [Centre for Proton Therapy, Paul Scherrer Institute, Villigen-PSI (Switzerland); Langendijk, Johannes A. [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)

    2012-02-01

    Purpose: To investigate whether intensity-modulated proton therapy with a reduced spot size (rsIMPT) could further reduce the parotid and submandibular gland dose compared with previously calculated IMPT plans with a larger spot size. In addition, it was investigated whether the obtained dose reductions would theoretically translate into a reduction of normal tissue complication probabilities (NTCPs). Methods: Ten patients with N0 oropharyngeal cancer were included in a comparative treatment planning study. Both IMPT plans delivered simultaneously 70 Gy to the boost planning target volume (PTV) and 54 Gy to the elective nodal PTV. IMPT and rsIMPT used identical three-field beam arrangements. In the IMPT plans, the parotid and submandibular salivary glands were spared as much as possible. rsIMPT plans used identical dose-volume objectives for the parotid glands as those used by the IMPT plans, whereas the objectives for the submandibular glands were tightened further. NTCPs were calculated for salivary dysfunction and xerostomia. Results: Target coverage was similar for both IMPT techniques, whereas rsIMPT clearly improved target conformity. The mean doses in the parotid glands and submandibular glands were significantly lower for three-field rsIMPT (14.7 Gy and 46.9 Gy, respectively) than for three-field IMPT (16.8 Gy and 54.6 Gy, respectively). Hence, rsIMPT significantly reduced the NTCP of patient-rated xerostomia and parotid and contralateral submandibular salivary flow dysfunction (27%, 17%, and 43% respectively) compared with IMPT (39%, 20%, and 79%, respectively). In addition, mean dose values in the sublingual glands, the soft palate and oral cavity were also decreased. Obtained dose and NTCP reductions varied per patient. Conclusions: rsIMPT improved sparing of the salivary glands and reduced NTCP for xerostomia and parotid and submandibular salivary dysfunction, while maintaining similar target coverage results. It is expected that rsIMPT improves quality

  11. Evaluation of surface and build-up region dose for intensity-modulated radiation therapy in head and neck cancer

    International Nuclear Information System (INIS)

    Chung, Heeteak; Jin, Hosang; Dempsey, James F.; Liu, Chihray; Palta, Jatinder; Suh, Tae-Suk; Kim, Siyong

    2005-01-01

    Despite much development, there remains dosimetric uncertainty in the surface and build-up regions in intensity-modulated radiation therapy treatment plans for head and neck cancers. Experiments were performed to determine the dosimetric discrepancies in the surface and build-up region between the treatment planning system (TPS) prediction and experimental measurement using radiochromic film. A head and neck compression film phantom was constructed from two semicylindrical solid water slabs. Treatment plans were generated using two commercial TPSs (PINNACLE3 and CORVUS) for two cases, one with a shallow (∼0.5 cm depth) target and another with a deep (∼6 cm depth) target. The plans were evaluated for a 54 Gy prescribed dose. For each case, two pieces of radiochromic film were used for dose measurement. A small piece of film strip was placed on the surface and another was inserted within the phantom. Overall, both TPSs showed good agreement with the measurement. For the shallow target case, the dose differences were within ±300 cGy (5.6% with respect to the prescribed dose) for PINNACLE3 and ±240 cGy (4.4%) for CORVUS in 90% of the region of interest. For the deep target case, the dose differences were ±350 (6.5%) for PINNACLE3 and ±260 cGy (4.8%) for CORVUS in 90% of the region of interest. However, it was found that there were significant discrepancies from the surface to about 0.2 cm in depth for both the shallow and deep target cases. It was concluded that both TPSs overestimated the surface dose for both shallow and deep target cases. The amount of overestimation ranges from 400 to 1000 cGy (∼7.4% to 18.5% with respect to the prescribed dose, 5400 cGy)

  12. Comparison of Kodak EDR2 and Gafchromic EBT film for intensity-modulated radiation therapy dose distribution verification.

    Science.gov (United States)

    Sankar, A; Ayyangar, Komanduri M; Nehru, R Mothilal; Kurup, P G Gopalakrishna; Murali, V; Enke, Charles A; Velmurugan, J

    2006-01-01

    The quantitative dose validation of intensity-modulated radiation therapy (IMRT) plans require 2-dimensional (2D) high-resolution dosimetry systems with uniform response over its sensitive region. The present work deals with clinical use of commercially available self-developing Radio Chromic Film, Gafchromic EBT film, for IMRT dose verification. Dose response curves were generated for the films using a VXR-16 film scanner. The results obtained with EBT films were compared with the results of Kodak extended dose range 2 (EDR2) films. The EBT film had a linear response between the dose range of 0 to 600 cGy. The dose-related characteristics of the EBT film, such as post irradiation color growth with time, film uniformity, and effect of scanning orientation, were studied. There was up to 8.6% increase in the color density between 2 to 40 hours after irradiation. There was a considerable variation, up to 8.5%, in the film uniformity over its sensitive region. The quantitative differences between calculated and measured dose distributions were analyzed using DTA and Gamma index with the tolerance of 3% dose difference and 3-mm distance agreement. The EDR2 films showed consistent results with the calculated dose distributions, whereas the results obtained using EBT were inconsistent. The variation in the film uniformity limits the use of EBT film for conventional large-field IMRT verification. For IMRT of smaller field sizes (4.5 x 4.5 cm), the results obtained with EBT were comparable with results of EDR2 films.

  13. Health-related quality of life using intensity-modulated radiation therapy for post-prostatectomy radiotherapy

    International Nuclear Information System (INIS)

    Van Gysen, Kirsten L.; Guo, Linxin; Kneebone, Andrew B.; Eade, Thomas N.; Vaux, Kenneth J.; Lazzaro, Enzo M.

    2013-01-01

    Post-prostatectomy radiotherapy (PPRT) with intensity-modulated radiation therapy (IMRT) has the potential to decrease toxicity by reducing dose to surrounding structures. We assessed its impact on health-related quality of life (HRQoL). PPRT patients were enrolled in a prospective HRQoL database. To be eligible, patients were required to be treated with IMRT and have a minimum of 15-month follow up. HRQoL was assessed at baseline, 3, 9 and 15–24 months using the Expanded Prostate Cancer Index Composite questionnaire. Higher scores reflected better HRQoL. Results were analysed as both population means and as individual scores where a moderate change was 10–20 points and a substantial change was >20 points. There were 64 patients eligible and 83% of the cohort received salvage radiotherapy. Prescribed dose was 64Gy in 32 fractions for adjuvant and 66Gy in 33 fractions for salvage IMRT. Mean function scores for urinary, bowel and sexual domains were similar at baseline and 15 months (83.5, 94.2 and 16.9 vs. 82.2, 93.1 and 14.3, respectively). Mean global physical functioning (51.0 vs. 48.1) and mental functioning (51.6 vs. 54.2) showed no difference over time. Individual patient scores by 2 years showed a >20-point deterioration in urinary (12.5%), bowel (1.6%), sexual function (9.4%), physical functioning (3.1%) and mental functioning (1.6%). This report on HRQoL following post-prostatectomy IMRT demonstrates no variation in mean scores in any domain and only 1.6% of patients reporting a greater than 20-point deterioration between baseline and 15–24 months in bowel function.

  14. Hypofractionated intensity-modulated arc therapy for lymph node metastasized prostate cancer: Early late toxicity and 3-year clinical outcome

    International Nuclear Information System (INIS)

    Fonteyne, Valérie; Lumen, Nicolaas; Ost, Piet; Van Praet, Charles; Vandecasteele, Katrien; De Gersem Ir, Werner; Villeirs, Geert; De Neve, Wilfried; Decaestecker, Karel; De Meerleer, Gert

    2013-01-01

    Background and purpose: For patients with N1 prostate cancer (PCa) aggressive local therapies can be advocated. We evaluated clinical outcome, gastro-intestinal (GI) and genito-urinary (GU) toxicity after intensity modulated arc radiotherapy (IMAT) + androgen deprivation (AD) for N1 PCa. Material and methods: Eighty patients with T1-4N1M0 PCa were treated with IMAT and 2–3 years of AD. A median dose of 69.3 Gy (normalized isoeffective dose at 2 Gy per fraction: 80 Gy [α/β = 3]) was prescribed in 25 fractions to the prostate. The pelvic lymph nodes received a minimal dose of 45 Gy. A simultaneous integrated boost to 72 Gy and 65 Gy was delivered to the intraprostatic lesion and/or pathologically enlarged lymph nodes, respectively. GI and GU toxicity was scored using the RTOG/RILIT and RTOG-SOMA/LENT-CTC toxicity scoring system respectively. Three-year actuarial risk of grade 2 and 3/4 GI–GU toxicity and biochemical and clinical relapse free survival (bRFS and cRFS) were calculated with Kaplan–Meier statistics. Results: Median follow-up was 36 months. Three-year actuarial risk for late grade 3 and 2 GI toxicity is 8% and 20%, respectively. Three-year actuarial risk for late grade 3–4 and 2 GU toxicity was 6% and 34%, respectively. Actuarial 3-year bRFS and cRFS was 81% and 89%, respectively. Actuarial 3-year bRFS and cRFS was, respectively 26% and 32% lower for patients with cN1 disease when compared to patients with cN0 disease. Conclusion: IMAT for N1 PCa offers good clinical outcome with moderate toxicity. Patients with cN1 disease have poorer outcome

  15. Cognitive Function Before and After Intensity-Modulated Radiation Therapy in Patients With Nasopharyngeal Carcinoma: A Prospective Study

    International Nuclear Information System (INIS)

    Hsiao, Kuan-Yin; Yeh, Shyh-An; Chang, Chiung-Chih

    2010-01-01

    Purpose: To evaluate the effects of radiation therapy (RT) on neurocognitive function in patients with nasopharyngeal carcinoma (NPC). Methods and Materials: Thirty patients with NPC treated with intensity-modulated RT were included. Dose-volume histograms of the temporal lobes were obtained in every patient. Neurocognitive tests were administered individually to each patient 1 day before initiation of RT and at least 12 months after completion of RT. Cognitive functioning status was evaluated as change in scores over time. Results: Among the total of 30 patients, 23 patients (76.7%) had significantly lower post-RT cognitive functioning scores compared with their pre-RT scores (p = 0.033). The cognitive functioning scores had significantly declined in the domains of short-term memory, language abilities, and list-generating fluency (p = 0.020, 0.023, and 0.001, respectively). Compared with patients with a mean dose to the temporal lobes of 36 Gy or less, patients with a mean dose of greater than 36 Gy had a significantly greater reduction in cognitive functioning scores (p = 0.017). Patients in whom V60 of the temporal lobes (i.e., the percentage of the temporal lobe volume that had received >60 Gy) was greater than 10% also had a greater reduction in cognitive functioning scores than those in whom V60 was 10% or less (p = 0.039). Conclusions: The results of our study indicated that RT could have deleterious effects on cognitive function in patients with NPC. Efforts should be made to reduce the radiation dose and irradiated volume of temporal lobes without compromising the coverage of target volume.

  16. Influence of intravenous contrast agent on dose calculations of intensity modulated radiation therapy plans for head and neck cancer

    International Nuclear Information System (INIS)

    Choi, Youngmin; Kim, Jeung-Kee; Lee, Hyung-Sik; Hur, Won-Joo; Hong, Young-Seoub; Park, Sungkwang; Ahn, Kijung; Cho, Heunglae

    2006-01-01

    Background and purpose: To evaluate the effect of an intravenous contrast agent (CA) on dose calculations and its clinical significance in intensity modulated radiation therapy (IMRT) plans for head and neck cancer. Materials and methods: Fifteen patients with head and neck cancer and involved neck nodes were enrolled. Each patient took two sets of computerized tomography (CT) in the same position before and after intravenous CA injections. Target volumes and organs at risk (OAR) were contoured on the enhanced CT, and then an IMRT plan of nine equiangular beams with a 6 MV X-ray was created. After the fusion of non-enhanced and enhanced CTs, the contours and the IMRT plan created from the enhanced CT were copied and placed to the non-enhanced CT. Doses were calculated again from the non-enhanced CT by the same IMRT plan. The radiation doses calculated from the two sets of CTs were compared with regard to planning target volumes (PTV) and the three OARs, both parotid glands and the spinal cord, by Wilcoxon's signed rank test. Results: The doses (maximum, mean, and the dose of 95% of PTV received (D 95% )) of PTV70 and PTV59.4 calculated from the enhanced CTs were lower than those from the non-enhanced CTs (p < 0.05), but the dose differences were less than 1% compared to the doses calculated from the enhanced CTs. The doses of PTV50.4, parotid glands, and spinal cord were not significantly different between the non-enhanced and enhanced CTs. Conclusions: The difference between the doses calculated from the CTs with and without CA enhancement was tolerably small, therefore using intravenous CA could be recommended for the planning CT of head and neck IMRT

  17. Fatigue is associated with inflammation in patients with head and neck cancer before and after intensity-modulated radiation therapy

    Science.gov (United States)

    Beitler, Jonathan J.; Higgins, Kristin A.; Conneely, Karen; Dwivedi, Bhakti; Felger, Jennifer; Wommack, Evanthia C.; Shin, Dong M.; Saba, Nabil F.; Ong, Luke Yeeloo; Kowalski, Jeanne; Bruner, Deborah W.; Miller, Andrew H.

    2016-01-01

    Patients with head and neck cancer (HNC) receiving intensity-modulated radiation therapy (IMRT) have particularly high rates of fatigue, and pre- and post-radiotherapy fatigue are prognostic factors for pathologic tumor responses and poor survival. Although inflammation has been proposed as one of the potential mechanisms of fatigue in cancer patients, findings have not been consistent, and there is a dearth of longitudinal studies. Accordingly, we conducted a prospective study in 46 HNC patients pre- and one-month post-IMRT. Fatigue was measured by the Multidimensional Fatigue Inventory (MFI)-20 at both time points along with the assessment of peripheral blood inflammatory markers including interleukin (IL)-6, soluble tumor necrosis factor receptor 2, and C-reactive protein (CRP) and gene expression. Generalized estimating equations were used to examine the association between inflammatory markers and fatigue. Gene enrichment analysis using MetaCore software was performed using up-regulated genes that were significantly associated with IMRT and fatigue. Significant associations between fatigue and IL-6 as well as CRP, which were independent of time, were observed. In addition the change in fatigue from pre- to post-IMRT was positively associated with the change in IL-6 and CRP. Analysis of up-regulated gene transcripts as a function of IMRT and fatigue revealed overrepresentation of transcripts related to the defense response and nuclear factor kappa B. In conclusion, our findings support the hypotheses that inflammation is associated with fatigue over time in HNC patients. Future studies on how inflammation contributes to fatigue as well as strategies targeting inflammation to reduce fatigue are warranted. PMID:26515035

  18. Hypofractionated Intensity Modulated Radiation Therapy in Combined Modality Treatment for Bladder Preservation in Elderly Patients With Invasive Bladder Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Turgeon, Guy-Anne [Department of Oncology, Division of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Souhami, Luis, E-mail: luis.souhami@muhc.mcgill.ca [Department of Oncology, Division of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Cury, Fabio L.; Faria, Sergio L.; Duclos, Marie [Department of Oncology, Division of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Sturgeon, Jeremy [Department of Medical Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Kassouf, Wassim [Department of Urology, McGill University Health Centre, Montreal, Quebec (Canada)

    2014-02-01

    Purpose/Objective(s): To review our experience with bladder-preserving trimodality treatment (TMT) using hypofractionated intensity modulated radiation therapy (IMRT) for the treatment of elderly patients with muscle-invasive bladder cancer. Methods and Materials: Retrospective study of elderly patients treated with TMT using hypofractionated IMRT (50 Gy in 20 fractions) with concomitant weekly radiosensitizing chemotherapy. Eligibility criteria were as follows: age ≥70 years, a proven diagnosis of muscle-invasive transitional cell bladder carcinoma, stage T2-T3N0M0 disease, and receipt of TMT with curative intent. Response rate was assessed by cystoscopic evaluation and bladder biopsy. Results: 24 patients with a median age of 79 years were eligible. A complete response was confirmed in 83% of the patients. Of the remaining patients, 1 of them underwent salvage cystectomy, and no disease was found in the bladder on histopathologic assessment. After a median follow-up time of 28 months, of the patients with a complete response, 2 patients had muscle-invasive recurrence, 1 experienced locoregional failure, and 3 experienced distant metastasis. The overall and cancer-specific survival rates at 3 years were 61% and 71%, respectively. Of the surviving patients, 75% have a disease-free and functioning bladder. All patients completed hypofractionated IMRT, and 19 patients tolerated all 4 cycles of chemotherapy. Acute grade 3 gastrointestinal or genitourinary toxicities occurred in only 4% of the patients, and acute grade 3 or 4 hematologic toxicities, liver toxicities, or both were experienced by 17% of the cohort. No patient experienced grade 4 gastrointestinal or genitourinary toxicity. Conclusions: Hypofractionated IMRT with concurrent radiosensitizing chemotherapy appears to be an effective and well-tolerated curative treatment strategy in the elderly population and should be considered for patients who are not candidates for cystectomy or who wish to avoid

  19. Brachial plexus dose tolerance in head and neck cancer patients treated with sequential intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Thomas, Tarita O; Refaat, Tamer; Choi, Mehee; Bacchus, Ian; Sachdev, Sean; Rademaker, Alfred W; Sathiaseelan, Vythialingam; Karagianis, Achilles; Mittal, Bharat B

    2015-01-01

    We aimed to study the radiation induced brachial plexopathy in patients with head and neck squamous cell carcinoma (HNSCC) treated with Sequential Intensity Modulated Radiation Therapy (S-IMRT). This IRB approved study included 68 patients with HNSCC treated consecutively. Detailed dose volume histogram data was generated for ipsilateral and contralateral brachial plexus (BP) volumes receiving a specified dose (Vds) i.e. V50-V75 and dose in Gray covering specified percent of BP volume (Dvs) i.e. D5-D30 and maximum point doses (Dmax). To assess BP injury all patients’ charts were reviewed in detail for sign and symptoms of BP damage. Post-hoc comparisons were done using Tukey-Kramer method to account for multiple significance testing. The mean and maximum doses to BP were significantly different (p < .05) based on tumor site, nodal status and tumor stage. The mean volume to the ipsilateral BP for V50, V60, V70, and V75 were 7.01 cc, 4.37 cc, 1.47 cc and 0.24 cc, respectively. The mean dose delivered to ≤5% of ipsilateral BP was 68.70 Gy (median 69.5Gy). None of the patients had acute or late brachial plexopathy or any other significant neurological complications, with a minimum follow up of two years (mean 54 months). In this study cohort, at a minimum of two-years follow up, the mean dose of 68.7Gy, a median dose to 69.5Gy to ≤5% of ipsilateral BP, and a median Dmax of 72.96Gy did not result in BP injury when patients were treated with S-IMRT technique. However, longer follow up is needed

  20. Convex reformulation of biologically-based multi-criteria intensity-modulated radiation therapy optimization including fractionation effects.

    Science.gov (United States)

    Hoffmann, Aswin L; den Hertog, Dick; Siem, Alex Y D; Kaanders, Johannes H A M; Huizenga, Henk

    2008-11-21

    Finding fluence maps for intensity-modulated radiation therapy (IMRT) can be formulated as a multi-criteria optimization problem for which Pareto optimal treatment plans exist. To account for the dose-per-fraction effect of fractionated IMRT, it is desirable to exploit radiobiological treatment plan evaluation criteria based on the linear-quadratic (LQ) cell survival model as a means to balance the radiation benefits and risks in terms of biologic response. Unfortunately, the LQ-model-based radiobiological criteria are nonconvex functions, which make the optimization problem hard to solve. We apply the framework proposed by Romeijn et al (2004 Phys. Med. Biol. 49 1991-2013) to find transformations of LQ-model-based radiobiological functions and establish conditions under which transformed functions result in equivalent convex criteria that do not change the set of Pareto optimal treatment plans. The functions analysed are: the LQ-Poisson-based model for tumour control probability (TCP) with and without inter-patient heterogeneity in radiation sensitivity, the LQ-Poisson-based relative seriality s-model for normal tissue complication probability (NTCP), the equivalent uniform dose (EUD) under the LQ-Poisson model and the fractionation-corrected Probit-based model for NTCP according to Lyman, Kutcher and Burman. These functions differ from those analysed before in that they cannot be decomposed into elementary EUD or generalized-EUD functions. In addition, we show that applying increasing and concave transformations to the convexified functions is beneficial for the piecewise approximation of the Pareto efficient frontier.

  1. Stereotactic intensity-modulated radiation therapy (IMRT) and inverse treatment planning for advanced pleural mesothelioma. Feasibility and initial results

    Energy Technology Data Exchange (ETDEWEB)

    Muenter, M.W.; Thilmann, C.; Hof, H.; Debus, J. [Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (dkfz), Heidelberg (Germany); Nill, S.; Hoess, A.; Partridge, M. [Dept. of Medical Physics, German Cancer Research Center (dkfz), Heidelberg (Germany); Haering, P. [Dept. of Central Dosimetry, German Cancer Research Center (dkfz), Heidelberg (Germany); Manegold, C. [Dept. of Medical Oncology/Internal Medicine, Thoraxklinik Heidelberg gGmbH, Heidelberg (Germany); Wannenmacher, M. [Dept. of Clinical Radiology, Univ. of Heidelberg, Heidelberg (Germany)

    2003-08-01

    Background and Purpose: Complex-shaped malignant pleural mesotheliomas (MPMs) with challenging volumes are extremely difficult to treat by conventional radiotherapy due to tolerance doses of the surrounding normal tissue. In a feasibility study, we evaluated if inversely planned stereotactic intensity-modulated radiation therapy (IMRT) could be applied in the treatment of MPM. Patients and Methods: Eight patients with unresectable lesions were treated after failure of chemotherapy. All patients were positioned using noninvasive patient fixation techniques which can be attached to the applied extracranial stereotactic system. Due to craniocaudal extension of the tumor, it was necessary to develop a special software attached to the inverse planning program KonRad, which can connect two inverse treatment plans and consider the applied dose of the first treatment plan in the area of the matchline of the second treatment plan. Results: Except for one patient, in whom radiotherapy was canceled due to abdominal metastasis, treatment could be completed in all patients and was well tolerated. Median survival after diagnosis was 20 months and after IMRT 6.5 months. Therefore, both the 1-year actuarial overall survival from the start of radiotherapy and the 2-year actuarial overall survival since diagnosis were 28%. IMRT did not result in clinically significant acute side effects. By using the described inverse planning software, over- or underdosage in the region of the field matchline could be prevented. Pure treatment time ranged between 10 and 21 min. Conclusion: This study showed that IMRT is feasible in advanced unresectable MPM. The presented possibilities of stereotactic IMRT in the treatment of MPM will justify the evaluation of IMRT in early-stage pleural mesothelioma combined with chemotherapy in a study protocol, in order to improve the outcome of these patients. Furthermore, dose escalation should be possible by using IMRT. (orig.)

  2. Surveillance on interfacility differences in dose-prescription policy of intensity-modulated radiation therapy plans for prostate cancer

    International Nuclear Information System (INIS)

    Mizowaki, Takashi; Hiraoka, Masahiro; Hatano, Kazuo

    2012-01-01

    Intensity-modulated radiation therapy (IMRT) has recently become popular in Japan. Prostate cancer is indisputably one of the main targets of IMRT. However, the current status and interfacility differences in dose-prescription policies for prostate IMRT are unknown. Therefore, a nationwide survey of 43 institutions that had implemented prostate IMRT was conducted by sending a questionnaire regarding the above-mentioned issues. Thirty-three institutions (77%) had responded to the questionnaire by the end of October 2010. A total of 5245 patients with localized prostate cancer had been treated with IMRT by the end of 2009. Regular multileaf collimator-based techniques were the most common beam delivery method. Dose-prescription policies were divided into four major categories: isocenter-based (at isocenter), dose delivered to 95% of the planning target volume (PTV) (D95)-based (D95 at PTV), mean dose to the PTV-based (Mean at PTV), and mean dose to the clinical target volume (CTV)-based (at CTV). The mean doses of the CTV and PTV, and the volume of the PTV receiving 95% of the dose (V95) were significantly higher with the D95 at PTV policy than with the other prescription policies. Low-dose areas and hot spots were observed within the PTV in plans with at isocenter and at CTV policies. In conclusion, there are currently considerable differences among institutions in Japan regarding target doses for prostate IMRT. The D95 at PTV prescription policy resulted in significant dose escalation compared with the other policies. These differences should be taken into consideration when interpreting treatment outcomes and creating multi-institutional protocols in the future. (author)

  3. Comparison of Kodak EDR2 and Gafchromic EBT film for intensity-modulated radiation therapy dose distribution verification

    International Nuclear Information System (INIS)

    Sankar, A.; Ayyangar, Komanduri M.; Nehru, R. Mothilal; Gopalakrishna Kurup, P.G.; Murali, V.; Enke, Charles A.; Velmurugan, J.

    2006-01-01

    The quantitative dose validation of intensity-modulated radiation therapy (IMRT) plans require 2-dimensional (2D) high-resolution dosimetry systems with uniform response over its sensitive region. The present work deals with clinical use of commercially available self-developing Radio Chromic Film, Gafchromic EBT film, for IMRT dose verification. Dose response curves were generated for the films using a VXR-16 film scanner. The results obtained with EBT films were compared with the results of Kodak extended dose range 2 (EDR2) films. The EBT film had a linear response between the dose range of 0 to 600 cGy. The dose-related characteristics of the EBT film, such as post irradiation color growth with time, film uniformity, and effect of scanning orientation, were studied. There was up to 8.6% increase in the color density between 2 to 40 hours after irradiation. There was a considerable variation, up to 8.5%, in the film uniformity over its sensitive region. The quantitative differences between calculated and measured dose distributions were analyzed using DTA and Gamma index with the tolerance of 3% dose difference and 3-mm distance agreement. The EDR2 films showed consistent results with the calculated dose distributions, whereas the results obtained using EBT were inconsistent. The variation in the film uniformity limits the use of EBT film for conventional large-field IMRT verification. For IMRT of smaller field sizes (4.5 x 4.5 cm), the results obtained with EBT were comparable with results of EDR2 films

  4. Whole abdomen radiation therapy in ovarian cancers: a comparison between fixed beam and volumetric arc based intensity modulation

    Directory of Open Access Journals (Sweden)

    Clivio Alessandro

    2010-11-01

    Full Text Available Abstract Purpose A study was performed to assess dosimetric characteristics of volumetric modulated arcs (RapidArc, RA and fixed field intensity modulated therapy (IMRT for Whole Abdomen Radiotherapy (WAR after ovarian cancer. Methods and Materials Plans for IMRT and RA were optimised for 5 patients prescribing 25 Gy to the whole abdomen (PTV_WAR and 45 Gy to the pelvis and pelvic nodes (PTV_Pelvis with Simultaneous Integrated Boost (SIB technique. Plans were investigated for 6 MV (RA6, IMRT6 and 15 MV (RA15, IMRT15 photons. Objectives were: for both PTVs V90% > 95%, for PTV_Pelvis: Dmax Results IMRT and RapidArc resulted comparable for target coverage. For PTV_WAR, V90% was 99.8 ± 0.2% and 93.4 ± 7.3% for IMRT6 and IMRT15, and 98.4 ± 1.7 and 98.6 ± 0.9% for RA6 and RA15. Target coverage resulted improved for PTV_Pelvis. Dose homogeneity resulted slightly improved by RA (Uniformity was defined as U5-95% = D5%-D95%/Dmean. U5-95% for PTV_WAR was 0.34 ± 0.05 and 0.32 ± 0.06 (IMRT6 and IMRT15, 0.30 ± 0.03 and 0.26 ± 0.04 (RA6 and RA15; for PTV_Pelvis, it resulted equal to 0.1 for all techniques. For organs at risk, small differences were observed between the techniques. MU resulted 3130 ± 221 (IMRT6, 2841 ± 318 (IMRT15, 538 ± 29 (RA6, 635 ± 139 (RA15; the average measured treatment time was 18.0 ± 0.8 and 17.4 ± 2.2 minutes (IMRT6 and IMRT15 and 4.8 ± 0.2 (RA6 and RA15. GAIIMRT6 = 97.3 ± 2.6%, GAIIMRT15 = 94.4 ± 2.1%, GAIRA6 = 98.7 ± 1.0% and GAIRA15 = 95.7 ± 3.7%. Conclusion RapidArc showed to be a solution to WAR treatments offering good dosimetric features with significant logistic improvements compared to IMRT.

  5. Whole abdomen radiation therapy in ovarian cancers: a comparison between fixed beam and volumetric arc based intensity modulation

    International Nuclear Information System (INIS)

    Mahantshetty, Umesh; Shrivastava, Shyamkishore; Cozzi, Luca; Jamema, Swamidas; Engineer, Reena; Deshpande, Deepak; Sarin, Rajiv; Fogliata, Antonella; Nicolini, Giorgia; Clivio, Alessandro; Vanetti, Eugenio

    2010-01-01

    A study was performed to assess dosimetric characteristics of volumetric modulated arcs (RapidArc, RA) and fixed field intensity modulated therapy (IMRT) for Whole Abdomen Radiotherapy (WAR) after ovarian cancer. Plans for IMRT and RA were optimised for 5 patients prescribing 25 Gy to the whole abdomen (PTV-WAR) and 45 Gy to the pelvis and pelvic nodes (PTV-Pelvis) with Simultaneous Integrated Boost (SIB) technique. Plans were investigated for 6 MV (RA6, IMRT6) and 15 MV (RA15, IMRT15) photons. Objectives were: for both PTVs V 90% > 95%, for PTV-Pelvis: D max < 105%; for organs at risk, maximal sparing was required. The MU and delivery time measured treatment efficiency. Pre-treatment Quality assurance was scored with Gamma Agreement Index (GAI) with 3% and 3 mm thresholds. IMRT and RapidArc resulted comparable for target coverage. For PTV-WAR, V 90% was 99.8 ± 0.2% and 93.4 ± 7.3% for IMRT6 and IMRT15, and 98.4 ± 1.7 and 98.6 ± 0.9% for RA6 and RA15. Target coverage resulted improved for PTV-Pelvis. Dose homogeneity resulted slightly improved by RA (Uniformity was defined as U 5-95% = D 5% -D 95% /D mean ). U 5 - 95% for PTV-WAR was 0.34 ± 0.05 and 0.32 ± 0.06 (IMRT6 and IMRT15), 0.30 ± 0.03 and 0.26 ± 0.04 (RA6 and RA15); for PTV-Pelvis, it resulted equal to 0.1 for all techniques. For organs at risk, small differences were observed between the techniques. MU resulted 3130 ± 221 (IMRT6), 2841 ± 318 (IMRT15), 538 ± 29 (RA6), 635 ± 139 (RA15); the average measured treatment time was 18.0 ± 0.8 and 17.4 ± 2.2 minutes (IMRT6 and IMRT15) and 4.8 ± 0.2 (RA6 and RA15). GAI IMRT6 = 97.3 ± 2.6%, GAI IMRT15 = 94.4 ± 2.1%, GAI RA6 = 98.7 ± 1.0% and GAI RA15 = 95.7 ± 3.7%. RapidArc showed to be a solution to WAR treatments offering good dosimetric features with significant logistic improvements compared to IMRT

  6. A dosimetric comparison of 3D conformal vs intensity modulated vs volumetric arc radiation therapy for muscle invasive bladder cancer

    International Nuclear Information System (INIS)

    Foroudi, Farshad; Kron, Tomas; Wilson, Lesley; Bressel, Mathias; Haworth, Annette; Hornby, Colin; Pham, Daniel; Cramb, Jim; Gill, Suki; Tai, Keen Hun

    2012-01-01

    To compare 3 Dimensional Conformal radiotherapy (3D-CRT) with Intensity Modulated Radiotherapy (IMRT) with Volumetric-Modulated Arc Therapy (VMAT) for bladder cancer. Radiotherapy plans for 15 patients with T2-T4N0M0 bladder cancer were prospectively developed for 3-DCRT, IMRT and VMAT using Varian Eclipse planning system. The same radiation therapist carried out all planning and the same clinical dosimetric constraints were used. 10 of the patients with well localised tumours had a simultaneous infield boost (SIB) of the primary tumour planned for both IMRT and VMAT. Tumour control probabilities and normal tissue complication probabilities were calculated. Mean planning time for 3D-CRT, IMRT and VMAT was 30.0, 49.3, and 141.0 minutes respectively. The mean PTV conformity (CI) index for 3D-CRT was 1.32, for IMRT 1.05, and for VMAT 1.05. The PTV Homogeneity (HI) index was 0.080 for 3D-CRT, 0.073 for IMRT and 0.086 for VMAT. Tumour control and normal tissue complication probabilities were similar for 3D-CRT, IMRT and VMAT. The mean monitor units were 267 (range 250–293) for 3D-CRT; 824 (range 641–1083) for IMRT; and 403 (range 333–489) for VMAT (P < 0.05). Average treatment delivery time were 2:25min (range 2:01–3:09) for 3D-CRT; 4:39 (range 3:41–6:40) for IMRT; and 1:14 (range 1:13–1:14) for VMAT. In selected patients, the SIB did not result in a higher dose to small bowel or rectum. VMAT is associated with similar dosimetric advantages as IMRT over 3D-CRT for muscle invasive bladder cancer. VMAT is associated with faster delivery times and less number of mean monitor units than IMRT. SIB is feasible in selected patients with localized tumours

  7. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a ⁶⁰Co Magnetic Resonance Image Guidance Radiation Therapy System.

    Science.gov (United States)

    Wooten, H Omar; Green, Olga; Yang, Min; DeWees, Todd; Kashani, Rojano; Olsen, Jeff; Michalski, Jeff; Yang, Deshan; Tanderup, Kari; Hu, Yanle; Li, H Harold; Mutic, Sasa

    2015-07-15

    This work describes a commercial treatment planning system, its technical features, and its capabilities for creating (60)Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. The ViewRay treatment planning system (Oakwood Village, OH) was used to create (60)Co IMRT treatment plans for 33 cancer patients with disease in the abdominal, pelvic, thorax, and head and neck regions using physician-specified patient-specific target coverage and organ at risk (OAR) objectives. Backup plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The (60)Co and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses and heterogeneity indices (HI) for planning target volumes (PTVs) and maximum, mean, and dose-volume histogram (DVH) values for OARs. All (60)Co IMRT plans achieved PTV coverage and OAR sparing that were similar to linac plans. PTV conformity for (60)Co was within 20 Gy. The mean doses for all (60)Co plan OARs were within clinical tolerances. A commercial (60)Co MR-IGRT device can produce highly conformal IMRT treatment plans similar in quality to linac IMRT for a variety of disease sites. Additional work is in progress to evaluate the clinical benefit of other novel features of this MR-IGRT system. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Intensity Modulated Radiation Therapy Dose Painting for Localized Prostate Cancer Using 11C-choline Positron Emission Tomography Scans

    International Nuclear Information System (INIS)

    Chang, Joe H.; Lim Joon, Daryl; Lee, Sze Ting; Gong, Sylvia J.; Anderson, Nigel J.; Scott, Andrew M.; Davis, Ian D.; Clouston, David; Bolton, Damien; Hamilton, Christopher S.; Khoo, Vincent

    2012-01-01

    Purpose: To demonstrate the technical feasibility of intensity modulated radiation therapy (IMRT) dose painting using 11 C-choline positron emission tomography PET scans in patients with localized prostate cancer. Methods and Materials: This was an RT planning study of 8 patients with prostate cancer who had 11 C-choline PET scans prior to radical prostatectomy. Two contours were semiautomatically generated on the basis of the PET scans for each patient: 60% and 70% of the maximum standardized uptake values (SUV 60% and SUV 70% ). Three IMRT plans were generated for each patient: PLAN 78 , which consisted of whole-prostate radiation therapy to 78 Gy; PLAN 78-90 , which consisted of whole-prostate RT to 78 Gy, a boost to the SUV 60% to 84 Gy, and a further boost to the SUV 70% to 90 Gy; and PLAN 72-90 , which consisted of whole-prostate RT to 72 Gy, a boost to the SUV 60% to 84 Gy, and a further boost to the SUV 70% to 90 Gy. The feasibility of these plans was judged by their ability to reach prescription doses while adhering to published dose constraints. Tumor control probabilities based on PET scan-defined volumes (TCP PET ) and on prostatectomy-defined volumes (TCP path ), and rectal normal tissue complication probabilities (NTCP) were compared between the plans. Results: All plans for all patients reached prescription doses while adhering to dose constraints. TCP PET values for PLAN 78 , PLAN 78-90 , and PLAN 72-90 were 65%, 97%, and 96%, respectively. TCP path values were 71%, 97%, and 89%, respectively. Both PLAN 78-90 and PLAN 72-90 had significantly higher TCP PET (P=.002 and .001) and TCP path (P 78 . PLAN 78-90 and PLAN 72-90 were not significantly different in terms of TCP PET or TCP path . There were no significant differences in rectal NTCPs between the 3 plans. Conclusions: IMRT dose painting for localized prostate cancer using 11 C-choline PET scans is technically feasible. Dose painting results in higher TCPs without higher NTCPs.

  9. Beam configuration selection for robust intensity-modulated proton therapy in cervical cancer using Pareto front comparison.

    Science.gov (United States)

    van de Schoot, A J A J; Visser, J; van Kesteren, Z; Janssen, T M; Rasch, C R N; Bel, A

    2016-02-21

    The Pareto front reflects the optimal trade-offs between conflicting objectives and can be used to quantify the effect of different beam configurations on plan robustness and dose-volume histogram parameters. Therefore, our aim was to develop and implement a method to automatically approach the Pareto front in robust intensity-modulated proton therapy (IMPT) planning. Additionally, clinically relevant Pareto fronts based on different beam configurations will be derived and compared to enable beam configuration selection in cervical cancer proton therapy. A method to iteratively approach the Pareto front by automatically generating robustly optimized IMPT plans was developed. To verify plan quality, IMPT plans were evaluated on robustness by simulating range and position errors and recalculating the dose. For five retrospectively selected cervical cancer patients, this method was applied for IMPT plans with three different beam configurations using two, three and four beams. 3D Pareto fronts were optimized on target coverage (CTV D(99%)) and OAR doses (rectum V30Gy; bladder V40Gy). Per patient, proportions of non-approved IMPT plans were determined and differences between patient-specific Pareto fronts were quantified in terms of CTV D(99%), rectum V(30Gy) and bladder V(40Gy) to perform beam configuration selection. Per patient and beam configuration, Pareto fronts were successfully sampled based on 200 IMPT plans of which on average 29% were non-approved plans. In all patients, IMPT plans based on the 2-beam set-up were completely dominated by plans with the 3-beam and 4-beam configuration. Compared to the 3-beam set-up, the 4-beam set-up increased the median CTV D(99%) on average by 0.2 Gy and decreased the median rectum V(30Gy) and median bladder V(40Gy) on average by 3.6% and 1.3%, respectively. This study demonstrates a method to automatically derive Pareto fronts in robust IMPT planning. For all patients, the defined four-beam configuration was found optimal

  10. Beam configuration selection for robust intensity-modulated proton therapy in cervical cancer using Pareto front comparison

    International Nuclear Information System (INIS)

    Van de Schoot, A J A J; Visser, J; Van Kesteren, Z; Rasch, C R N; Bel, A; Janssen, T M

    2016-01-01

    The Pareto front reflects the optimal trade-offs between conflicting objectives and can be used to quantify the effect of different beam configurations on plan robustness and dose-volume histogram parameters. Therefore, our aim was to develop and implement a method to automatically approach the Pareto front in robust intensity-modulated proton therapy (IMPT) planning. Additionally, clinically relevant Pareto fronts based on different beam configurations will be derived and compared to enable beam configuration selection in cervical cancer proton therapy. A method to iteratively approach the Pareto front by automatically generating robustly optimized IMPT plans was developed. To verify plan quality, IMPT plans were evaluated on robustness by simulating range and position errors and recalculating the dose. For five retrospectively selected cervical cancer patients, this method was applied for IMPT plans with three different beam configurations using two, three and four beams. 3D Pareto fronts were optimized on target coverage (CTV D 99% ) and OAR doses (rectum V 30Gy ; bladder V 40Gy ). Per patient, proportions of non-approved IMPT plans were determined and differences between patient-specific Pareto fronts were quantified in terms of CTV D 99% , rectum V 30Gy and bladder V 40Gy to perform beam configuration selection. Per patient and beam configuration, Pareto fronts were successfully sampled based on 200 IMPT plans of which on average 29% were non-approved plans. In all patients, IMPT plans based on the 2-beam set-up were completely dominated by plans with the 3-beam and 4-beam configuration. Compared to the 3-beam set-up, the 4-beam set-up increased the median CTV D 99% on average by 0.2 Gy and decreased the median rectum V 30Gy and median bladder V 40Gy on average by 3.6% and 1.3%, respectively. This study demonstrates a method to automatically derive Pareto fronts in robust IMPT planning. For all patients, the defined four-beam configuration was found optimal in

  11. Intensity Modulated Proton Therapy for Craniospinal Irradiation: Organ-at-Risk Exposure and a Low-Gradient Junctioning Technique

    International Nuclear Information System (INIS)

    Stoker, Joshua B.; Grant, Jonathan; Zhu, X. Ronald; Pidikiti, Rajesh; Mahajan, Anita; Grosshans, David R.

    2014-01-01

    Purpose: To compare field junction robustness and sparing of organs at risk (OARs) during craniospinal irradiation (CSI) using intensity modulated proton therapy (IMPT) to conventional passively scattered proton therapy (PSPT). Methods and Materials: Ten patients, 5 adult and 5 pediatric patients, previously treated with PSPT-based CSI were selected for comparison. Anterior oblique cranial fields, using a superior couch rotation, and posterior spinal fields were used for IMPT planning. To facilitate low-gradient field junctioning along the spine, the inverse-planning IMPT technique was divided into 3 stages. Dose indices describing target coverage and normal tissue dose, in silico error modeling, and film dosimetry were used to assess plan quality. Results: Field junction robustness along the spine was improved using the staged IMPT planning technique, reducing the worst case impact of a 4-mm setup error from 25% in PSPT to <5% of prescription dose. This was verified by film dosimetry for clinical delivery. Exclusive of thyroid dose in adult patients, IMPT plans demonstrated sparing of organs at risk as good or better than PSPT. Coverage of the cribriform plate for pediatric (V95% [percentage of volume of the target receiving at least 95% of the prescribed dose]; 87 ± 11 vs 92 ± 7) and adult (V95%; 94 ± 7 vs 100 ± 1) patients and the clinical target in pediatric (V95%; 98 ± 2 vs 100 ± 1) and adult (V95%; 100 ± 1 vs 100 ± 1) patients for PSPT and IMPT plans, respectively, were comparable or improved. For adult patients, IMPT target dose inhomogeneity was increased, as determined by heterogeneity index (HI) and inhomogeneity coefficient (IC). IMPT lowered maximum spinal cord dose, improved spinal dose homogeneity, and reduced exposure to other OARs. Conclusions: IMPT has the potential to improve CSI plan quality and the homogeneity of intrafractional dose at match lines. The IMPT approach developed may also simplify treatments and reduce

  12. High-dose intensity modulated radiation therapy for prostate cancer: early toxicity and biochemical outcome in 772 patients

    International Nuclear Information System (INIS)

    Zelefsky, Michael J.; Fuks, Zvi; Hunt, Margie; Yamada, Yoshiya; Marion, Christine; Ling, C. Clifton; Amols, Howard; Venkatraman, E.S.; Leibel, Steven A.

    2002-01-01

    Purpose: To report the acute and late toxicity and preliminary biochemical outcomes in 772 patients with clinically localized prostate cancer treated with high-dose intensity-modulated radiotherapy (IMRT). Methods and Materials: Between April 1996 and January 2001, 772 patients with clinically localized prostate cancer were treated with IMRT. Treatment was planned using an inverse-planning approach, and the desired beam intensity profiles were delivered by dynamic multileaf collimation. A total of 698 patients (90%) were treated to 81.0 Gy, and 74 patients (10%) were treated to 86.4 Gy. Acute and late toxicities were scored by the Radiation Therapy Oncology Group morbidity grading scales. PSA relapse was defined according to The American Society of Therapeutic Radiation Oncology Consensus Statement. The median follow-up time was 24 months (range: 6-60 months). Results: Thirty-five patients (4.5%) developed acute Grade 2 rectal toxicity, and no patient experienced acute Grade 3 or higher rectal symptoms. Two hundred seventeen patients (28%) developed acute Grade 2 urinary symptoms, and one experienced urinary retention (Grade 3). Eleven patients (1.5%) developed late Grade 2 rectal bleeding. Four patients (0.1%) experienced Grade 3 rectal toxicity requiring either one or more transfusions or a laser cauterization procedure. No Grade 4 rectal complications have been observed. The 3-year actuarial likelihood of ≥ late Grade 2 rectal toxicity was 4%. Seventy-two patients (9%) experienced late Grade 2 urinary toxicity, and five (0.5%) developed Grade 3 urinary toxicity (urethral stricture). The 3-year actuarial likelihood of ≥ late Grade 2 urinary toxicity was 15%. The 3-year actuarial PSA relapse-free survival rates for favorable, intermediate, and unfavorable risk group patients were 92%, 86%, and 81%, respectively. Conclusions: These data demonstrate the feasibility of high-dose IMRT in a large number of patients. Acute and late rectal toxicities seem to be

  13. Comparison of intensity-modulated radiotherapy and volumetric-modulated arc therapy dose measurement for head and neck cancer using optical stimulated luminescence dosimeter

    International Nuclear Information System (INIS)

    Lai, Lu-Han; Chuang, Keh-Shih; Lin, Hsin-Hon; Liu, Yi-Chi; Kuo, Chiung-Wen; Lin, Jao-Perng

    2017-01-01

    The in-vivo dose distributions of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT), a newly developed technique, for head and neck cancer have been investigated for several years. The present study used a head-and-neck RANDO phantom to simulate the clinical conditions of nasopharyngeal carcinoma and compare the radiation doses between VMAT and IMRT. Three types of planning target volume (PTV) profiles were targeted by reducing the PTV surface margin by 0, 3, and 5 mm. An optically stimulated luminescence dosimeter was used to measure the surface doses. The results revealed that VMAT provided on average 16.8–13.8% lower surface doses within the PTV target areas than IMRT. When the PTV margin was reduced by 0 mm, the surface doses for IMRT reached their maximum value, accounting for 75.1% of its prescribed dose (Dp); however, the Dp value of VMAT was only 61.1%. When the PTV margin was reduced by 3 or 5 mm, the surface doses decreased considerably. The observed surface doses were insufficient when the tumours invaded the body surface; however, VMAT exerted larger skin-sparing effects than IMRT when the tumours away from the skin. These results suggest that the skin doses for these two techniques are insufficient for surface tumours. Notably, VMAT can provide lower skin doses for deep tumours. - Highlights: • The surface doses of NPC patients are compared between VMAT and IMRT. • VMAT exerts lower skin dose than IMRT for deep tumours. • The surface tumour coverage is insufficient for VMAT and IMRT.

  14. Dosimetric comparison of intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) in total scalp irradiation: a single institutional experience

    International Nuclear Information System (INIS)

    Ostheimer, Christian; Huebsch, Patrick; Janich, Martin; Gerlach, Reinhard; Vordermark, Dirk

    2016-01-01

    Total scalp irradiation (TSI) is a rare but challenging indication. We previously reported that non-coplanar intensity-modulated radiotherapy (IMRT) was superior to coplanar IMRT in organ-at-risk (OAR) protection and target dose distribution. This consecutive treatment planning study compared IMRT with volumetric-modulated arc therapy (VMAT). A retrospective treatment plan databank search was performed and 5 patient cases were randomly selected. Cranial imaging was restored from the initial planning computed tomography (CT) and target volumes and OAR were redelineated. For each patients, three treatment plans were calculated (coplanar/non-coplanar IMRT, VMAT; prescribed dose 50 Gy, single dose 2 Gy). Conformity, homogeneity and dose volume histograms were used for plan. VMAT featured the lowest monitor units and the sharpest dose gradient (1.6 Gy/mm). Planning target volume (PTV) coverage and homogeneity was better in VMAT (coverage, 0.95; homogeneity index [HI], 0.118) compared to IMRT (coverage, 0.94; HI, 0.119) but coplanar IMRT produced the most conformal plans (conformity index [CI], 0.43). Minimum PTV dose range was 66.8% –88.4% in coplanar, 77.5%–88.2% in non-coplanar IMRT and 82.8%–90.3% in VMAT. Mean dose to the brain, brain stem, optic system (maximum dose) and lenses were 18.6, 13.2, 9.1, and 5.2 Gy for VMAT, 21.9, 13.4, 14.5, and 6.3 Gy for non-coplanar and 22.8, 16.5, 11.5, and 5.9 Gy for coplanar IMRT. Maximum optic chiasm dose was 7.7, 8.4, and 11.1 Gy (non-coplanar IMRT, VMAT, and coplanar IMRT). Target coverage, homogeneity and OAR protection, was slightly superior in VMAT plans which also produced the sharpest dose gradient towards healthy tissue

  15. Dosimetric comparison of intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) in total scalp irradiation: a single institutional experience

    Energy Technology Data Exchange (ETDEWEB)

    Ostheimer, Christian; Huebsch, Patrick; Janich, Martin; Gerlach, Reinhard; Vordermark, Dirk [Dept. of Radiation Oncology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, Halle (Germany)

    2016-12-15

    Total scalp irradiation (TSI) is a rare but challenging indication. We previously reported that non-coplanar intensity-modulated radiotherapy (IMRT) was superior to coplanar IMRT in organ-at-risk (OAR) protection and target dose distribution. This consecutive treatment planning study compared IMRT with volumetric-modulated arc therapy (VMAT). A retrospective treatment plan databank search was performed and 5 patient cases were randomly selected. Cranial imaging was restored from the initial planning computed tomography (CT) and target volumes and OAR were redelineated. For each patients, three treatment plans were calculated (coplanar/non-coplanar IMRT, VMAT; prescribed dose 50 Gy, single dose 2 Gy). Conformity, homogeneity and dose volume histograms were used for plan. VMAT featured the lowest monitor units and the sharpest dose gradient (1.6 Gy/mm). Planning target volume (PTV) coverage and homogeneity was better in VMAT (coverage, 0.95; homogeneity index [HI], 0.118) compared to IMRT (coverage, 0.94; HI, 0.119) but coplanar IMRT produced the most conformal plans (conformity index [CI], 0.43). Minimum PTV dose range was 66.8% –88.4% in coplanar, 77.5%–88.2% in non-coplanar IMRT and 82.8%–90.3% in VMAT. Mean dose to the brain, brain stem, optic system (maximum dose) and lenses were 18.6, 13.2, 9.1, and 5.2 Gy for VMAT, 21.9, 13.4, 14.5, and 6.3 Gy for non-coplanar and 22.8, 16.5, 11.5, and 5.9 Gy for coplanar IMRT. Maximum optic chiasm dose was 7.7, 8.4, and 11.1 Gy (non-coplanar IMRT, VMAT, and coplanar IMRT). Target coverage, homogeneity and OAR protection, was slightly superior in VMAT plans which also produced the sharpest dose gradient towards healthy tissue.

  16. Spot-scanning beam proton therapy vs intensity-modulated radiation therapy for ipsilateral head and neck malignancies: A treatment planning comparison

    International Nuclear Information System (INIS)

    Kandula, Shravan; Zhu, Xiaorong; Garden, Adam S.; Gillin, Michael; Rosenthal, David I.; Ang, Kie-Kian; Mohan, Radhe; Amin, Mayankkumar V.; Garcia, John A.; Wu, Richard; Sahoo, Narayan; Frank, Steven J.

    2013-01-01

    Radiation therapy for head and neck malignancies can have side effects that impede quality of life. Theoretically, proton therapy can reduce treatment-related morbidity by minimizing the dose to critical normal tissues. We evaluated the feasibility of spot-scanning proton therapy for head and neck malignancies and compared dosimetry between those plans and intensity-modulated radiation therapy (IMRT) plans. Plans from 5 patients who had undergone IMRT for primary tumors of the head and neck were used for planning proton therapy. Both sets of plans were prepared using computed tomography (CT) scans with the goals of achieving 100% of the prescribed dose to the clinical target volume (CTV) and 95% to the planning TV (PTV) while maximizing conformity to the PTV. Dose-volume histograms were generated and compared, as were conformity indexes (CIs) to the PTVs and mean doses to the organs at risk (OARs). Both modalities in all cases achieved 100% of the dose to the CTV and 95% to the PTV. Mean PTV CIs were comparable (0.371 IMRT, 0.374 protons, p = 0.953). Mean doses were significantly lower in the proton plans to the contralateral submandibular (638.7 cGy IMRT, 4.3 cGy protons, p = 0.002) and parotid (533.3 cGy IMRT, 48.5 cGy protons, p = 0.003) glands; oral cavity (1760.4 cGy IMRT, 458.9 cGy protons, p = 0.003); spinal cord (2112.4 cGy IMRT, 249.2 cGy protons, p = 0.002); and brainstem (1553.52 cGy IMRT, 166.2 cGy protons, p = 0.005). Proton plans also produced lower maximum doses to the spinal cord (3692.1 cGy IMRT, 2014.8 cGy protons, p = 0.034) and brainstem (3412.1 cGy IMRT, 1387.6 cGy protons, p = 0.005). Normal tissue V 10 , V 30 , and V 50 values were also significantly lower in the proton plans. We conclude that spot-scanning proton therapy can significantly reduce the integral dose to head and neck critical structures. Prospective studies are underway to determine if this reduced dose translates to improved quality of life

  17. Prospective Randomized Phase 2 Trial of Intensity Modulated Radiation Therapy With or Without Oncolytic Adenovirus-Mediated Cytotoxic Gene Therapy in Intermediate-Risk Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Freytag, Svend O., E-mail: sfreyta1@hfhs.org [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Stricker, Hans [Vattikuti Urology Institute, Henry Ford Health System, Detroit, Michigan (United States); Lu, Mei [Public Health Sciences, Henry Ford Health System, Detroit, Michigan (United States); Elshaikh, Mohamed; Aref, Ibrahim; Pradhan, Deepak; Levin, Kenneth; Kim, Jae Ho [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Peabody, James [Vattikuti Urology Institute, Henry Ford Health System, Detroit, Michigan (United States); Siddiqui, Farzan; Barton, Kenneth; Pegg, Jan; Zhang, Yingshu; Cheng, Jingfang [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Oja-Tebbe, Nancy; Bourgeois, Renee [Public Health Sciences, Henry Ford Health System, Detroit, Michigan (United States); Gupta, Nilesh; Lane, Zhaoli [Pathology, Henry Ford Health System, Detroit, Michigan (United States); Rodriguez, Ron [Urology, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); DeWeese, Theodore [Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); and others

    2014-06-01

    Purpose: To assess the safety and efficacy of combining oncolytic adenovirus-mediated cytotoxic gene therapy (OAMCGT) with intensity modulated radiation therapy (IMRT) in intermediate-risk prostate cancer. Methods and Materials: Forty-four men with intermediate-risk prostate cancer were randomly assigned to receive either OAMCGT plus IMRT (arm 1; n=21) or IMRT only (arm 2; n=23). The primary phase 2 endpoint was acute (≤90 days) toxicity. Secondary endpoints included quality of life (QOL), prostate biopsy (12-core) positivity at 2 years, freedom from biochemical/clinical failure (FFF), freedom from metastases, and survival. Results: Men in arm 1 exhibited a greater incidence of low-grade influenza-like symptoms, transaminitis, neutropenia, and thrombocytopenia than men in arm 2. There were no significant differences in gastrointestinal or genitourinary events or QOL between the 2 arms. Two-year prostate biopsies were obtained from 37 men (84%). Thirty-three percent of men in arm 1 were biopsy-positive versus 58% in arm 2, representing a 42% relative reduction in biopsy positivity in the investigational arm (P=.13). There was a 60% relative reduction in biopsy positivity in the investigational arm in men with <50% positive biopsy cores at baseline (P=.07). To date, 1 patient in each arm exhibited biochemical failure (arm 1, 4.8%; arm 2, 4.3%). No patient developed hormone-refractory or metastatic disease, and none has died from prostate cancer. Conclusions: Combining OAMCGT with IMRT does not exacerbate the most common side effects of prostate radiation therapy and suggests a clinically meaningful reduction in positive biopsy results at 2 years in men with intermediate-risk prostate cancer.

  18. Assessment of organ dose reduction and secondary cancer risk associated with the use of proton beam therapy and intensity modulated radiation therapy in treatment of neuroblastomas

    International Nuclear Information System (INIS)

    Fuji, Hiroshi; Harada, Hideyuki; Asakura, Hirofumi; Nishimura, Tetsuo; Schneider, Uwe; Ishida, Yuji; Konno, Masahiro; Yamashita, Haruo; Kase, Yuki; Murayama, Shigeyuki; Onoe, Tsuyoshi; Ogawa, Hirofumi

    2013-01-01

    To compare proton beam therapy (PBT) and intensity-modulated radiation therapy (IMRT) with conformal radiation therapy (CRT) in terms of their organ doses and ability to cause secondary cancer in normal organs. Five patients (median age, 4 years; range, 2–11 years) who underwent PBT for retroperitoneal neuroblastoma were selected for treatment planning simulation. Four patients had stage 4 tumors and one had stage 2A tumor, according to the International Neuroblastoma Staging System. Two patients received 36 Gy, two received 21.6 Gy, and one received 41.4 Gy of radiation. The volume structures of these patients were used for simulations of CRT and IMRT treatment. Dose–volume analyses of liver, stomach, colon, small intestine, pancreas, and bone were performed for the simulations. Secondary cancer risks in these organs were calculated using the organ equivalent dose (OED) model, which took into account the rates of cell killing, repopulation, and the neutron dose from the treatment machine. In all evaluated organs, the mean dose in PBT was 20–80% of that in CRT. IMRT also showed lower mean doses than CRT for two organs (20% and 65%), but higher mean doses for the other four organs (110–120%). The risk of secondary cancer in PBT was 24–83% of that in CRT for five organs, but 121% of that in CRT for pancreas. The risk of secondary cancer in IMRT was equal to or higher than CRT for four organs (range 100–124%). Low radiation doses in normal organs are more frequently observed in PBT than in IMRT. Assessments of secondary cancer risk showed that PBT reduces the risk of secondary cancer in most organs, whereas IMRT is associated with a higher risk than CRT

  19. Two-Year and Lifetime Cost-Effectiveness of Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy for Head-and-Neck Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, Racquel E. [Department of Health Policy and Management, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Sheets, Nathan C. [Department of Radiation Oncology, University of North Carolina Hospitals, Chapel Hill, North Carolina (United States); Wheeler, Stephanie B. [Department of Health Policy and Management, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Nutting, Chris [Royal Marsden Hospital, London, United Kindom (United Kingdom); Hall, Emma [Clinical Trials and Statistics Unit, Division of Clinical Studies, Institute of Cancer Research, London (United Kingdom); Chera, Bhishamjit S., E-mail: bchera@med.unc.edu [Department of Radiation Oncology, University of North Carolina Hospitals, Chapel Hill, North Carolina (United States)

    2013-11-15

    Purpose: To assess the cost-effectiveness of intensity modulated radiation therapy (IMRT) versus 3-dimensional conformal radiation therapy (3D-CRT) in the treatment of head-and neck-cancer (HNC). Methods and Materials: We used a Markov model to simulate radiation therapy-induced xerostomia and dysphagia in a hypothetical cohort of 65-year-old HNC patients. Model input parameters were derived from PARSPORT (CRUK/03/005) patient-level trial data and quality-of-life and Medicare cost data from published literature. We calculated average incremental cost-effectiveness ratios (ICERs) from the US health care perspective as cost per quality-adjusted life-year (QALY) gained and compared our ICERs with current cost-effectiveness standards whereby treatment comparators less than $50,000 per QALY gained are considered cost-effective. Results: In the first 2 years after initial treatment, IMRT is not cost-effective compared with 3D-CRT, given an average ICER of $101,100 per QALY gained. However, over 15 years (remaining lifetime on the basis of average life expectancy of a 65-year-old), IMRT is more cost-effective at $34,523 per QALY gained. Conclusion: Although HNC patients receiving IMRT will likely experience reduced xerostomia and dysphagia symptoms, the small quality-of-life benefit associated with IMRT is not cost-effective in the short term but may be cost-effective over a patient's lifetime, assuming benefits persist over time and patients are healthy and likely to live for a sustained period. Additional data quantifying the long-term benefits of IMRT, however, are needed.

  20. Comparative Cost-Effectiveness of Stereotactic Body Radiation Therapy Versus Intensity-Modulated and Proton Radiation Therapy for Localized Prostate Cancer

    International Nuclear Information System (INIS)

    Parthan, Anju; Pruttivarasin, Narin; Davies, Diane; Taylor, Douglas C. A.; Pawar, Vivek; Bijlani, Akash; Lich, Kristen Hassmiller; Chen, Ronald C.

    2012-01-01

    Objective: To determine the cost-effectiveness of several external beam radiation treatment modalities for the treatment of patients with localized prostate cancer. Methods: A lifetime Markov model incorporated the probabilities of experiencing treatment-related long-term toxicity or death. Toxicity probabilities were derived from published sources using meta-analytical techniques. Utilities and costs in the model were obtained from publicly available secondary sources. The model calculated quality-adjusted life expectancy and expected lifetime cost per patient, and derived ratios of incremental cost per quality-adjusted life year (QALY) gained between treatments. Analyses were conducted from both payer and societal perspectives. One-way and probabilistic sensitivity analyses were performed. Results: Compared to intensity-modulated radiation therapy (IMRT) and proton beam therapy (PT), stereotactic body radiation therapy (SBRT) was less costly and resulted in more QALYs. Sensitivity analyses showed that the conclusions in the base-case scenario were robust with respect to variations in toxicity and cost parameters consistent with available evidence. At a threshold of $50,000/QALY, SBRT was cost-effective in 75% and 94% of probabilistic simulations compared to IMRT and PT, respectively, from a payer perspective. From a societal perspective, SBRT was cost-effective in 75% and 96% of simulations compared to IMRT and PT, respectively, at a threshold of $50,000/QALY. In threshold analyses, SBRT was less expensive with better outcomes compared to IMRT at toxicity rates 23% greater than the SBRT base-case rates. Conclusion: Based on the assumption that each treatment modality results in equivalent long-term efficacy, SBRT is a cost-effective strategy resulting in improved quality-adjusted survival compared to IMRT and PT for the treatment of localized prostate cancer.

  1. Comparative cost-effectiveness of stereotactic body radiation therapy versus intensity-modulated and proton radiation therapy for localized prostate cancer.

    Directory of Open Access Journals (Sweden)

    Anju eParthan

    2012-08-01

    Full Text Available Objective. To determine the cost-effectiveness of several external beam radiation treatment modalities for the treatment of patients with localized prostate cancer.Methods. A lifetime Markov model incorporated the probabilities of experiencing treatment-related long-term toxicity or death. Toxicity probabilities were derived from published sources using meta-analytical techniques. Utilities and costs in the model were obtained from publically available secondary sources. The model calculated quality-adjusted life expectancy and expected lifetime cost per patient, and derived ratios of incremental cost per quality-adjusted life year (QALY gained between treatments. Analyses were conducted from both a payer and societal perspectives. One-way and probabilistic sensitivity analyses were performed.Results. Compared to intensity modulated radiation therapy (IMRT and proton beam therapy (PT, stereotactic body radiation therapy (SBRT was less costly and resulted in more QALYs. Sensitivity analyses showed that the conclusions in the base-case scenario were robust with respect to variations in toxicity and cost parameters consistent with available evidence. At a threshold of $50,000/QALY, SBRT was cost effective in 75%, and 94% of probabilistic simulations compared to IMRT and PT, respectively, from a payer perspective. From a societal perspective, SBRT was cost-effective in 75%, and 96% of simulations compared to IMRT and PT, respectively, at a threshold of $50,000/QALY. In threshold analyses, SBRT was less expensive with better outcomes compared to IMRT at toxicity rates 23% greater than the SBRT base-case rates. Conclusions. Based on the assumption that each treatment modality results in equivalent long-term efficacy, SBRT is a cost-effective strategy resulting in improved quality-adjusted survival compared to IMRT and PT for the treatment of localized prostate cancer.

  2. Prospective Randomized Phase 2 Trial of Intensity Modulated Radiation Therapy With or Without Oncolytic Adenovirus-Mediated Cytotoxic Gene Therapy in Intermediate-Risk Prostate Cancer

    International Nuclear Information System (INIS)

    Freytag, Svend O.; Stricker, Hans; Lu, Mei; Elshaikh, Mohamed; Aref, Ibrahim; Pradhan, Deepak; Levin, Kenneth; Kim, Jae Ho; Peabody, James; Siddiqui, Farzan; Barton, Kenneth; Pegg, Jan; Zhang, Yingshu; Cheng, Jingfang; Oja-Tebbe, Nancy; Bourgeois, Renee; Gupta, Nilesh; Lane, Zhaoli; Rodriguez, Ron; DeWeese, Theodore

    2014-01-01

    Purpose: To assess the safety and efficacy of combining oncolytic adenovirus-mediated cytotoxic gene therapy (OAMCGT) with intensity modulated radiation therapy (IMRT) in intermediate-risk prostate cancer. Methods and Materials: Forty-four men with intermediate-risk prostate cancer were randomly assigned to receive either OAMCGT plus IMRT (arm 1; n=21) or IMRT only (arm 2; n=23). The primary phase 2 endpoint was acute (≤90 days) toxicity. Secondary endpoints included quality of life (QOL), prostate biopsy (12-core) positivity at 2 years, freedom from biochemical/clinical failure (FFF), freedom from metastases, and survival. Results: Men in arm 1 exhibited a greater incidence of low-grade influenza-like symptoms, transaminitis, neutropenia, and thrombocytopenia than men in arm 2. There were no significant differences in gastrointestinal or genitourinary events or QOL between the 2 arms. Two-year prostate biopsies were obtained from 37 men (84%). Thirty-three percent of men in arm 1 were biopsy-positive versus 58% in arm 2, representing a 42% relative reduction in biopsy positivity in the investigational arm (P=.13). There was a 60% relative reduction in biopsy positivity in the investigational arm in men with <50% positive biopsy cores at baseline (P=.07). To date, 1 patient in each arm exhibited biochemical failure (arm 1, 4.8%; arm 2, 4.3%). No patient developed hormone-refractory or metastatic disease, and none has died from prostate cancer. Conclusions: Combining OAMCGT with IMRT does not exacerbate the most common side effects of prostate radiation therapy and suggests a clinically meaningful reduction in positive biopsy results at 2 years in men with intermediate-risk prostate cancer

  3. 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

  4. SU-E-T-338: Dosimetric Study of Volumetric Modulated Arc Therapy (VMAT) and Intensity Modulated Radiation Therapy (IMRT) for Stereotactic Body Radiation Therapy (SBRT) in Early Stage Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I; Quinn, K; Seebach, A; Wang, H [OSF Saint Anthony Medical Center, Rockford, IL (United States); Yah, R [University of Illinois College of Medicine at Rockford, Rockford, IL (United States)

    2015-06-15

    Purpose: This study evaluates the dosimetric differences using volumetric modulated arc therapy (VMAT) in patients previously treated with intensity modulated radiation therapy IMRT for stereotactic body radiotherapy (SBRT) in early stage lung cancer. Methods: We evaluated 9 consecutive medically inoperable lung cancer patients at the start of the SBRT program who were treated with IMRT from November 2010 to October 2011. These patients were treated using 6 MV energy. The 9 cases were then re-planned with VMAT performed with arc therapy using 6 MV flattening filter free (FFF) energy with the same organs at risk (OARS) constraints. Data collected for the treatment plans included target coverage, beam on time, dose to OARS and gamma pass rate. Results: Five patients were T1N0 and four patients were T2N0 with all tumors less than 5 cm. The average GTV was 13.02 cm3 (0.83–40.87) and average PTV was 44.65 cm3 (14.06–118.08). The IMRT plans had a mean of 7.2 angles (6–9) and 5.4 minutes (3.6–11.1) per plan. The VMAT plans had a mean of 2.8 arcs (2–3) and 4.0 minutes (2.2–6.0) per plan. VMAT had slightly more target coverage than IMRT with average increase in D95 of 2.68% (1.24–5.73) and D99 of 3.65% (0.88–8.77). VMAT produced lower doses to all OARs. The largest reductions were in maximum doses to the spinal cord with an average reduction of 24.1%, esophagus with an average reduction of 22.1%, and lung with an average reduction in the V20 of 16.3% The mean gamma pass rate was 99.8% (99.2–100) at 3 mm and 3% for VMAT with comparable values for IMRT. Conclusion: These findings suggest that using VMAT for SBRT in early stage lung cancer is superior to IMRT in terms of dose coverage, OAR dose and a lower treatment delivery time with a similar gamma pass rate.

  5. Impact of Spot Size and Spacing on the Quality of Robustly Optimized Intensity Modulated Proton Therapy Plans for Lung Cancer.

    Science.gov (United States)

    Liu, Chenbin; Schild, Steven E; Chang, Joe Y; Liao, Zhongxing; Korte, Shawn; Shen, Jiajian; Ding, Xiaoning; Hu, Yanle; Kang, Yixiu; Keole, Sameer R; Sio, Terence T; Wong, William W; Sahoo, Narayan; Bues, Martin; Liu, Wei

    2018-06-01

    To investigate how spot size and spacing affect plan quality, robustness, and interplay effects of robustly optimized intensity modulated proton therapy (IMPT) for lung cancer. Two robustly optimized IMPT plans were created for 10 lung cancer patients: first by a large-spot machine with in-air energy-dependent large spot size at isocenter (σ: 6-15 mm) and spacing (1.3 σ), and second by a small-spot machine with in-air energy-dependent small spot size (σ: 2-6 mm) and spacing (5 mm). Both plans were generated by optimizing radiation dose to internal target volume on averaged 4-dimensional computed tomography scans using an in-house-developed IMPT planning system. The dose-volume histograms band method was used to evaluate plan robustness. Dose evaluation software was developed to model time-dependent spot delivery to incorporate interplay effects with randomized starting phases for each field per fraction. Patient anatomy voxels were mapped phase-to-phase via deformable image registration, and doses were scored using in-house-developed software. Dose-volume histogram indices, including internal target volume dose coverage, homogeneity, and organs at risk (OARs) sparing, were compared using the Wilcoxon signed-rank test. Compared with the large-spot machine, the small-spot machine resulted in significantly lower heart and esophagus mean doses, with comparable target dose coverage, homogeneity, and protection of other OARs. Plan robustness was comparable for targets and most OARs. With interplay effects considered, significantly lower heart and esophagus mean doses with comparable target dose coverage and homogeneity were observed using smaller spots. Robust optimization with a small spot-machine significantly improves heart and esophagus sparing, with comparable plan robustness and interplay effects compared with robust optimization with a large-spot machine. A small-spot machine uses a larger number of spots to cover the same tumors compared with a large

  6. SU-C-BRD-01: A Statistical Modeling Method for Quality Control of Intensity- Modulated Radiation Therapy Planning

    International Nuclear Information System (INIS)

    Gao, S; Meyer, R; Shi, L; D'Souza, W; Zhang, H

    2014-01-01

    Purpose: To apply a statistical modeling approach, threshold modeling (TM), for quality control of intensity-modulated radiation therapy (IMRT) treatment plans. Methods: A quantitative measure, which was the weighted sum of violations of dose/dose-volume constraints, was first developed to represent the quality of each IMRT plan. Threshold modeling approach, which is is an extension of extreme value theory in statistics and is an effect way to model extreme values, was then applied to analyze the quality of the plans summarized by our quantitative measures. Our approach modeled the plans generated by planners as a series of independent and identically distributed random variables and described the behaviors of them if the plan quality was controlled below certain threshold. We tested our approach with five locally advanced head and neck cancer patients retrospectively. Two statistics were incorporated for numerical analysis: probability of quality improvement (PQI) of the plans and expected amount of improvement on the quantitative measure (EQI). Results: After clinical planners generated 15 plans for each patient, we applied our approach to obtain the PQI and EQI as if planners would generate additional 15 plans. For two of the patients, the PQI was significantly higher than the other three (0.17 and 0.18 comparing to 0.08, 0.01 and 0.01). The actual percentage of the additional 15 plans that outperformed the best of initial 15 plans was 20% and 27% comparing to 11%, 0% and 0%. EQI for the two potential patients were 34.5 and 32.9 and the rest of three patients were 9.9, 1.4 and 6.6. The actual improvements obtained were 28.3 and 20.5 comparing to 6.2, 0 and 0. Conclusion: TM is capable of reliably identifying the potential quality improvement of IMRT plans. It provides clinicians an effective tool to assess the trade-off between extra planning effort and achievable plan quality. This work was supported in part by NIH/NCI grant CA130814

  7. Involved-Site Image-Guided Intensity Modulated Versus 3D Conformal Radiation Therapy in Early Stage Supradiaphragmatic Hodgkin Lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Filippi, Andrea Riccardo, E-mail: andreariccardo.filippi@unito.it [Department of Oncology, University of Torino, Torino (Italy); Ciammella, Patrizia [Radiation Therapy Unit, Department of Oncology and Advanced Technology, ASMN Hospital IRCCS, Reggio Emilia (Italy); Piva, Cristina; Ragona, Riccardo [Department of Oncology, University of Torino, Torino (Italy); Botto, Barbara [Hematology, Città della Salute e della Scienza, Torino (Italy); Gavarotti, Paolo [Hematology, University of Torino and Città della Salute e della Scienza, Torino (Italy); Merli, Francesco [Hematology Unit, ASMN Hospital IRCCS, Reggio Emilia (Italy); Vitolo, Umberto [Hematology, Città della Salute e della Scienza, Torino (Italy); Iotti, Cinzia [Radiation Therapy Unit, Department of Oncology and Advanced Technology, ASMN Hospital IRCCS, Reggio Emilia (Italy); Ricardi, Umberto [Department of Oncology, University of Torino, Torino (Italy)

    2014-06-01

    Purpose: Image-guided intensity modulated radiation therapy (IG-IMRT) allows for margin reduction and highly conformal dose distribution, with consistent advantages in sparing of normal tissues. The purpose of this retrospective study was to compare involved-site IG-IMRT with involved-site 3D conformal RT (3D-CRT) in the treatment of early stage Hodgkin lymphoma (HL) involving the mediastinum, with efficacy and toxicity as primary clinical endpoints. Methods and Materials: We analyzed 90 stage IIA HL patients treated with either involved-site 3D-CRT or IG-IMRT between 2005 and 2012 in 2 different institutions. Inclusion criteria were favorable or unfavorable disease (according to European Organization for Research and Treatment of Cancer criteria), complete response after 3 to 4 cycles of an adriamycin- bleomycin-vinblastine-dacarbazine (ABVD) regimen plus 30 Gy as total radiation dose. Exclusion criteria were chemotherapy other than ABVD, partial response after ABVD, total radiation dose other than 30 Gy. Clinical endpoints were relapse-free survival (RFS) and acute toxicity. Results: Forty-nine patients were treated with 3D-CRT (54.4%) and 41 with IG-IMRT (45.6%). Median follow-up time was 54.2 months for 3D-CRT and 24.1 months for IG-IMRT. No differences in RFS were observed between the 2 groups, with 1 relapse each. Three-year RFS was 98.7% for 3D-CRT and 100% for IG-IMRT. Grade 2 toxicity events, mainly mucositis, were recorded in 32.7% of 3D-CRT patients (16 of 49) and in 9.8% of IG-IMRT patients (4 of 41). IG-IMRT was significantly associated with a lower incidence of grade 2 acute toxicity (P=.043). Conclusions: RFS rates at 3 years were extremely high in both groups, albeit the median follow-up time is different. Acute tolerance profiles were better for IG-IMRT than for 3D-CRT. Our preliminary results support the clinical safety and efficacy of advanced RT planning and delivery techniques in patients affected with early stage HL, achieving complete

  8. Evaluation of a leaf position optimization tool for intensity modulated radiation therapy of head and neck cancer

    International Nuclear Information System (INIS)

    Claus, Filip; Gersem, Werner de; Vanhoutte, Ilse; Duthoy, Wim; Remouchamps, Vincent; Wagter, Carlos de; Neve, Wilfried de

    2001-01-01

    Background and purpose: Since 1996, patients are treated at Ghent University Hospital with a multi-segment technique using MultiLeaf Collimators. The segments were obtained by using the Beam's eye view projections of the planning target volume (PTV) and the organs at risk (OARs), after which the segments weights were optimized. To investigate if optimization of the leaf positions would further improve the intensity modulated radiation therapy (IMRT) plans, a tool optimizing leaf positions and segment weights simultaneously, was developed. This tool is called SOWAT, which is the acronym for segment outline and weight adapting tool. Material and methods: The tool evaluates the effects of changing the position of each collimating leaf of all segments on the value of the objective function. Only changes that improve the value of the objective function are retained. Between December 1999 and January 2001, 30 head and neck patients were treated with IMRT. Two patient groups were distinguished: pharyngeal and laryngeal tumors (n=17) and sinonasal tumors (n=13). A specific set of physical endpoints was evaluated for each group. Dose statistics of the treatment plans without and with SOWAT were analyzed. Results: When using SOWAT for the pharyngeal and laryngeal cases, the PTV dose homogeneity increased with a median of 11% (range 2-27%), while the maximum dose to the spinal cord was decreased for 14 of the 17 patients. In four plans where parotid function preservation was a goal, the parotid mean dose was lower than 26 Gy in one plan without SOWAT, and in four plans with SOWAT. For the sinonasal tumors, the PTV dose homogeneity increased with a median of 7% (range 1-14%). SOWAT lowered the mean dose to 53 of the 63 optic pathway structures (retina, optic nerve and optic chiasm). SOWAT leaves the number of segments unchanged and has little or no effect on the delivery time. Conclusions: SOWAT is a powerful tool to perform the final optimization of IMRT plans, without

  9. Intensity-Modulated Radiotherapy Reduces Gastrointestinal Toxicity in Patients Treated With Androgen Deprivation Therapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Sharma, Navesh K.; Li Tianyu; Chen, David Y.; Pollack, Alan; Horwitz, Eric M.; Buyyounouski, Mark K.

    2011-01-01

    Purpose: Androgen deprivation therapy (AD) has been shown to increase late Grade 2 or greater rectal toxicity when used concurrently with three-dimensional conformal radiotherapy (3D-CRT). Intensity-modulated radiotherapy (IMRT) has the potential to reduce toxicity by limiting the radiation dose received by the bowel and bladder. The present study compared the genitourinary and gastrointestinal (GI) toxicity in men treated with 3D-CRT+AD vs. IMRT+AD. Methods and Materials: Between July 1992 and July 2004, 293 men underwent 3D-CRT (n = 170) or IMRT (n = 123) with concurrent AD (<6 months, n = 123; ≥6 months, n = 170). The median radiation dose was 76 Gy for 3D-CRT (International Commission on Radiation Units and Measurements) and 76 Gy for IMRT (95% to the planning target volume). Toxicity was assessed by a patient symptom questionnaire that was completed at each visit and recorded using a Fox Chase Modified Late Effects Normal Tissue Task radiation morbidity scale. Results: The mean follow-up was 86 months (standard deviation, 29.3) for the 3D-CRT group and 40 months (standard deviation, 9.7) for the IMRT group. Acute GI toxicity (odds ratio, 4; 95% confidence interval, 1.6-11.7; p = .005) was significantly greater with 3D-CRT than with IMRT and was independent of the AD duration (i.e., <6 vs. ≥6 months). The interval to the development of late GI toxicity was significantly longer in the IMRT group. The 5-year Kaplan-Meier estimate for Grade 2 or greater GI toxicity was 20% for 3D-CRT and 8% for IMRT (p = .01). On multivariate analysis, Grade 2 or greater late GI toxicity (hazard ratio, 2.1; 95% confidence interval, 1.1-4.3; p = .04) was more prevalent in the 3D-CRT patients. Conclusion: Compared with 3D-CRT, IMRT significantly decreased the acute and late GI toxicity in patients treated with AD.

  10. Inter fractional dose variation during intensity-modulated radiation therapy for cervical cancer assessed by weekly CT evaluation

    International Nuclear Information System (INIS)

    Han, Youngyih; Shin, Eun Hyuk; Huh, Seung Jae; Lee, Jung Eun; Park, Won

    2006-01-01

    Purpose: To investigate the inter fractional dose variation of a small-bowel displacement system (SBDS)-assisted intensity-modulated radiation therapy (IMRT) for the treatment of cervical cancer. Methods: Four computed tomography (CT) scans were carried out in 10 patients who received radiotherapy for uterine cervical cancer. The initial CT was taken by use of the SBDS, before the beginning of radiotherapy, and 3 additional CT scans with the SBDS were done in subsequent weeks. IMRT was planned by use of the initial CT, and the subsequent images were fused with the initial CT set. Dose-volume histogram (DVH) changes of the targets (planning target volume [PTV] = clinical target volume [CTV] + 1.5 cm) and of the critical organs were evaluated after obtaining the volumes of each organ on 4 CT sets. Results: No significant differences were found in PTV volumes. Changes on the DVH of the CTVs were not significant, whereas DVH changes of the PTVs at 40% to 100% of the prescription dose level were significant (V 90% ; 2nd week: p = 0.0091, 3rd week: p = 0.0029, 4th week: p = 0.0050). The changes in the small-bowel volume included in the treatment field were significant. These were 119.5 cm 3 (range, 26.9-251.0 cm 3 ), 126 cm 3 (range, 38.3-336 cm 3 ), 161.9 cm 3 (range, 37.7-294.6 cm 3 ), and 149.1 cm 3 (range, 38.6-277.8 cm 3 ) at the 1st, 2nd, 3rd, and 4th weeks, respectively, and were significantly correlated with the DVH change in the small bowel, which were significant at the 3rd (V 80% ; p = 0.0230) and 4th (V 80% ; p = 0.0263) weeks. The bladder-volume change correlated to the large volume change (>20%) of the small-bowel volume. Conclusions: Significant DVH differences for the small bowel can result because of interfractional position variations, whereas the DVH differences of the CTV were not significant. Strict bladder-filling control and an accurate margin for the PTV, as well as image-guided position verification, are important to achieve the goal of IMRT

  11. Effect of Intensity Modulated Radiation Therapy With Concurrent Chemotherapy on Survival for Patients With Cervical Esophageal Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, Lachlan J.; Huang, Shao Hui [Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada); Xu, Wei; Che, Jiahua [Department of Biostatistics, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada); Wong, Rebecca K.S.; Brierley, James; Kim, John; Cummings, Bernard; Waldron, John; Bayley, Andrew [Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada); Hansen, Aaron [Division of Medical Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada); Witterick, Ian [Department of Otolaryngology–Head and Neck Surgery, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada); Ringash, Jolie, E-mail: jolie.ringash@rmp.uhn.ca [Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada)

    2017-05-01

    Purpose: We evaluated the effect of consecutive protocols on overall survival (OS) for cervical esophageal carcinoma (CEC). Methods and Materials: All CEC cases that received definitive radiation therapy (RT) with or without chemotherapy from 1997 to 2013 in 3 consecutive protocols were reviewed. Protocol 1 (P1) consisted of 2-dimensional RT of 54 Gy in 20 fractions with 5-fluorouracil plus either mitomycin C or cisplatin. Protocol 2 (P2) consisted of 3-dimensional conformal RT (3DRT) of ≥60 Gy in 30 fractions plus elective nodal irradiation plus cisplatin. Protocol 3 (P3) consisted of intensity modulated RT (IMRT) of ≥60 Gy in 30 fractions plus elective nodal irradiation plus cisplatin. Multivariable analyses were used to assess the effect of the treatment protocol, RT technique, and RT dose on OS, separately. Results: Of 81 cases (P1, 21; P2, 23; and P3, 37), 34 local (P1, 11 [52%]; P2, 12 [52%]; and P3, 11 [30%]), 16 regional (P1, 6 [29%]); P2, 3 [13%]; and P3, 7 [19%]), and 34 distant (P1, 10 [48%]; P2, 9 [39%]; and P3, 15 [41%]) failures were identified. After adjusting for age (P=.49) and chemotherapy (any vs none; hazard ratio [HR] 0.5, 95% confidence interval [CI] 0.3-0.9; P=.023), multivariable analysis showed P3 had improved OS compared with P1 (HR 0.4, 95% CI 0.2-0.8; P=.005), with a trend shown for benefit compared with P2 (HR 0.6, 95% CI 0.3-1.0; P=.061). OS between P1 and P2 did not differ (P=.29). Analyzed as a continuous variable, higher RT doses were associated with a borderline improved OS (HR 0.97, 95% CI 0.95-1.0; P=.075). IMRT showed improved OS compared with non-IMRT (HR 0.57, 95% CI 0.3-0.8; P=.008). Conclusions: The present retrospective consecutive cohort study showed improved OS with our current protocol (P3; high-dose IMRT with concurrent high-dose cisplatin) compared with historical protocols. The outcomes for patients with CEC remain poor, and novel approaches to improve the therapeutic ratio are warranted.

  12. Evaluation and mitigation of the interplay effects for intensity modulated proton therapy for lung cancer in a clinical setting

    Science.gov (United States)

    Kardar, Laleh; Li, Yupeng; Li, Xiaoqiang; Li, Heng; Cao, Wenhua; Chang, Joe Y.; Liao, Li; Zhu, Ronald X.; Sahoo, Narayan; Gillin, Michael; Liao, Zhongxing; Komaki, Ritsuko; Cox, James D.; Lim, Gino; Zhang, Xiaodong

    2015-01-01

    Purpose The primary aim of this study was to evaluate the impact of interplay effects for intensity-modulated proton therapy (IMPT) plans for lung cancer in the clinical setting. The secondary aim was to explore the technique of iso-layered re-scanning for mitigating these interplay effects. Methods and Materials Single-fraction 4D dynamic dose without considering re-scanning (1FX dynamic dose) was used as a metric to determine the magnitude of dosimetric degradation caused by 4D interplay effects. The 1FX dynamic dose was calculated by simulating the machine delivery processes of proton spot scanning on moving patient described by 4D computed tomography (4DCT) during the IMPT delivery. The dose contributed from an individual spot was fully calculated on the respiratory phase corresponding to the life span of that spot, and the final dose was accumulated to a reference CT phase by using deformable image registration. The 1FX dynamic dose was compared with the 4D composite dose. Seven patients with various tumor volumes and motions were selected. Results The CTV prescription coverage for the 7 patients were 95.04%, 95.38%, 95.39%, 95.24%, 95.65%, 95.90%, and 95.53%, calculated with use of the 4D composite dose, and were 89.30%, 94.70%, 85.47%, 94.09%, 79.69%, 91.20%, and 94.19% with use of the 1FX dynamic dose. For the 7 patients, the CTV coverage, calculated by using single-fraction dynamic dose, were 95.52%, 95.32%, 96.36%, 95.28%, 94.32%, 95.53%, and 95.78%, using maximum MU limit value of 0.005. In other words, by increasing the number of delivered spots in each fraction, the degradation of CTV coverage improved up to 14.6%. Conclusions Single-fraction 4D dynamic dose without re-scanning was validated as a surrogate to evaluate the interplay effects for IMPT for lung cancer in the clinical setting. The interplay effects can be potentially mitigated by increasing the number of iso-layered re-scanning in each fraction delivery. PMID:25407877

  13. Evaluation and mitigation of the interplay effects of intensity modulated proton therapy for lung cancer in a clinical setting.

    Science.gov (United States)

    Kardar, Laleh; Li, Yupeng; Li, Xiaoqiang; Li, Heng; Cao, Wenhua; Chang, Joe Y; Liao, Li; Zhu, Ronald X; Sahoo, Narayan; Gillin, Michael; Liao, Zhongxing; Komaki, Ritsuko; Cox, James D; Lim, Gino; Zhang, Xiaodong

    2014-01-01

    The primary aim of this study was to evaluate the impact of the interplay effects of intensity modulated proton therapy (IMPT) plans for lung cancer in the clinical setting. The secondary aim was to explore the technique of isolayered rescanning to mitigate these interplay effects. A single-fraction 4-dimensional (4D) dynamic dose without considering rescanning (1FX dynamic dose) was used as a metric to determine the magnitude of dosimetric degradation caused by 4D interplay effects. The 1FX dynamic dose was calculated by simulating the machine delivery processes of proton spot scanning on a moving patient, described by 4D computed tomography during IMPT delivery. The dose contributed from an individual spot was fully calculated on the respiratory phase that corresponded to the life span of that spot, and the final dose was accumulated to a reference computed tomography phase by use of deformable image registration. The 1FX dynamic dose was compared with the 4D composite dose. Seven patients with various tumor volumes and motions were selected for study. The clinical target volume (CTV) prescription coverage for the 7 patients was 95.04%, 95.38%, 95.39%, 95.24%, 95.65%, 95.90%, and 95.53% when calculated with the 4D composite dose and 89.30%, 94.70%, 85.47%, 94.09%, 79.69%, 91.20%, and 94.19% when calculated with the 1FX dynamic dose. For these 7 patients, the CTV coverage calculated by use of a single-fraction dynamic dose was 95.52%, 95.32%, 96.36%, 95.28%, 94.32%, 95.53%, and 95.78%, with a maximum monitor unit limit value of 0.005. In other words, by increasing the number of delivered spots in each fraction, the degradation of CTV coverage improved up to 14.6%. A single-fraction 4D dynamic dose without rescanning was validated as a surrogate to evaluate the interplay effects of IMPT for lung cancer in the clinical setting. The interplay effects potentially can be mitigated by increasing the amount of isolayered rescanning in each fraction delivery.

  14. Outcomes and Patterns of Failure for Grade 2 Meningioma Treated With Reduced-Margin Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Press, Robert H. [Department of Radiation Oncology, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Prabhu, Roshan S., E-mail: roshansprabhu@gmail.com [Department of Radiation Oncology, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Appin, Christina L.; Brat, Daniel J. [Department of Pathology, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Shu, Hui-Kuo G. [Department of Radiation Oncology, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Hadjipanayis, Constantinos; Olson, Jeffrey J.; Oyesiku, Nelson M. [Department of Neurosurgery, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Curran, Walter J.; Crocker, Ian [Department of Radiation Oncology, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States)

    2014-04-01

    Purpose: The purpose of this study was to evaluate intracranial control and patterns of local recurrence (LR) for grade 2 meningiomas treated with intensity modulated radiation therapy (IMRT) with limited total margin expansions of ≤1 cm. Methods and Materials: We reviewed records of patients with a neuropathological diagnosis of grade 2 meningioma who underwent IMRT at our institution between 2002 and 2012. Actuarial rates were determined by the Kaplan-Meier method from the end of RT. LR was defined as in-field if ≥90% of the recurrence was within the prescription isodose, out-of-field (marginal) if ≥90% was outside of the prescription isodose, and both if neither criterion was met. Results: Between 2002 and 2012, a total of 54 consecutive patients underwent IMRT for grade 2 meningioma. Eight of these patients had total initial margins >1 cm and were excluded, leaving 46 patients for analysis. The median imaging follow-up period was 26.2 months (range, 7-107 months). The median dose for fractionated IMRT was 59.4 Gy (range, 49.2-61.2 Gy). Median clinical target volume (CTV), planning target volume (PTV), and total margin expansion were 0.5 cm, 0.3 cm, and 0.8 cm, respectively. LR occurred in 8 patients (17%), with 2-year and 3-year actuarial local control (LC) of 92% and 74%, respectively. Six of 8 patients (85%) had a known pattern of failure. Five patients (83%) had in-field LR; no patients had marginal LR; and 1 patient (17%) had both. Conclusions: The use of IMRT to treat grade 2 meningiomas with total initial margins (CTV + PTV) ≤1 cm did not appear to compromise outcomes or increase marginal failures compared with other modern retrospective series. Of the 46 patients who had margins ≤1 cm, none experienced marginal failure only. These results demonstrate efficacy and low risk of marginal failure after IMRT treatment of grade 2 meningiomas with reduced margins, warranting study within a prospective clinical trial.

  15. Treatment and prognosis of patients with late rectal bleeding after intensity-modulated radiation therapy for prostate cancer

    International Nuclear Information System (INIS)

    Takemoto, Shinya; Kataoka, Hiromi; Mimura, Mikio; Shibamoto, Yuta; Ayakawa, Shiho; Nagai, Aiko; Hayashi, Akihiro; Ogino, Hiroyuki; Baba, Fumiya; Yanagi, Takeshi; Sugie, Chikao

    2012-01-01

    Radiation proctitis after intensity-modulated radiation therapy (IMRT) differs from that seen after pelvic irradiation in that this adverse event is a result of high-dose radiation to a very small area in the rectum. We evaluated the results of treatment for hemorrhagic proctitis after IMRT for prostate cancer. Between November 2004 and February 2010, 403 patients with prostate cancer were treated with IMRT at 2 institutions. Among these patients, 64 patients who developed late rectal bleeding were evaluated. Forty patients had received IMRT using a linear accelerator and 24 by tomotherapy. Their median age was 72 years. Each patient was assessed clinically and/or endoscopically. Depending on the severity, steroid suppositories or enemas were administered up to twice daily and Argon plasma coagulation (APC) was performed up to 3 times. Response to treatment was evaluated using the Rectal Bleeding Score (RBS), which is the sum of Frequency Score (graded from 1 to 3 by frequency of bleeding) and Amount Score (graded from 1 to 3 by amount of bleeding). Stoppage of bleeding over 3 months was scored as RBS 1. The median follow-up period for treatment of rectal bleeding was 35 months (range, 12–69 months). Grade of bleeding was 1 in 31 patients, 2 in 26, and 3 in 7. Nineteen of 45 patients (42%) observed without treatment showed improvement and bleeding stopped in 17 (38%), although mean RBS did not change significantly. Eighteen of 29 patients (62%) treated with steroid suppositories or enemas showed improvement (mean RBS, from 4.1 ± 1.0 to 3.0 ± 1.8, p = 0.003) and bleeding stopped in 9 (31%). One patient treated with steroid enema 0.5-2 times a day for 12 months developed septic shock and died of multiple organ failure. All 12 patients treated with APC showed improvement (mean RBS, 4.7 ± 1.2 to 2.3 ± 1.4, p < 0.001) and bleeding stopped in 5 (42%). After adequate periods of observation, steroid suppositories/enemas are expected to be effective. However, short

  16. Treatment and prognosis of patients with late rectal bleeding after intensity-modulated radiation therapy for prostate cancer

    Directory of Open Access Journals (Sweden)

    Takemoto Shinya

    2012-06-01

    Full Text Available Abstract Background Radiation proctitis after intensity-modulated radiation therapy (IMRT differs from that seen after pelvic irradiation in that this adverse event is a result of high-dose radiation to a very small area in the rectum. We evaluated the results of treatment for hemorrhagic proctitis after IMRT for prostate cancer. Methods Between November 2004 and February 2010, 403 patients with prostate cancer were treated with IMRT at 2 institutions. Among these patients, 64 patients who developed late rectal bleeding were evaluated. Forty patients had received IMRT using a linear accelerator and 24 by tomotherapy. Their median age was 72 years. Each patient was assessed clinically and/or endoscopically. Depending on the severity, steroid suppositories or enemas were administered up to twice daily and Argon plasma coagulation (APC was performed up to 3 times. Response to treatment was evaluated using the Rectal Bleeding Score (RBS, which is the sum of Frequency Score (graded from 1 to 3 by frequency of bleeding and Amount Score (graded from 1 to 3 by amount of bleeding. Stoppage of bleeding over 3 months was scored as RBS 1. Results The median follow-up period for treatment of rectal bleeding was 35 months (range, 12–69 months. Grade of bleeding was 1 in 31 patients, 2 in 26, and 3 in 7. Nineteen of 45 patients (42% observed without treatment showed improvement and bleeding stopped in 17 (38%, although mean RBS did not change significantly. Eighteen of 29 patients (62% treated with steroid suppositories or enemas showed improvement (mean RBS, from 4.1 ± 1.0 to 3.0 ± 1.8, p = 0.003 and bleeding stopped in 9 (31%. One patient treated with steroid enema 0.5-2 times a day for 12 months developed septic shock and died of multiple organ failure. All 12 patients treated with APC showed improvement (mean RBS, 4.7 ± 1.2 to 2.3 ± 1.4, p  Conclusions After adequate periods of observation, steroid suppositories

  17. Exploratory Study of 4D versus 3D Robust Optimization in Intensity Modulated Proton Therapy for Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wei, E-mail: Liu.Wei@mayo.edu [Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, Arizona (United States); Schild, Steven E. [Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, Arizona (United States); Chang, Joe Y.; Liao, Zhongxing [Department of Radiation Oncology, the University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chang, Yu-Hui [Division of Health Sciences Research, Mayo Clinic Arizona, Phoenix, Arizona (United States); Wen, Zhifei [Department of Radiation Physics, the University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Shen, Jiajian; Stoker, Joshua B.; Ding, Xiaoning; Hu, Yanle [Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, Arizona (United States); Sahoo, Narayan [Department of Radiation Physics, the University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Herman, Michael G. [Department of Radiation Oncology, Mayo Clinic Rochester, Rochester, Minnesota (United States); Vargas, Carlos; Keole, Sameer; Wong, William; Bues, Martin [Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, Arizona (United States)

    2016-05-01

    Purpose: The purpose of this study was to compare the impact of uncertainties and interplay on 3-dimensional (3D) and 4D robustly optimized intensity modulated proton therapy (IMPT) plans for lung cancer in an exploratory methodology study. Methods and Materials: IMPT plans were created for 11 nonrandomly selected non-small cell lung cancer (NSCLC) cases: 3D robustly optimized plans on average CTs with internal gross tumor volume density overridden to irradiate internal target volume, and 4D robustly optimized plans on 4D computed tomography (CT) to irradiate clinical target volume (CTV). Regular fractionation (66 Gy [relative biological effectiveness; RBE] in 33 fractions) was considered. In 4D optimization, the CTV of individual phases received nonuniform doses to achieve a uniform cumulative dose. The root-mean-square dose-volume histograms (RVH) measured the sensitivity of the dose to uncertainties, and the areas under the RVH curve (AUCs) were used to evaluate plan robustness. Dose evaluation software modeled time-dependent spot delivery to incorporate interplay effect with randomized starting phases of each field per fraction. Dose-volume histogram (DVH) indices comparing CTV coverage, homogeneity, and normal tissue sparing were evaluated using Wilcoxon signed rank test. Results: 4D robust optimization plans led to smaller AUC for CTV (14.26 vs 18.61, respectively; P=.001), better CTV coverage (Gy [RBE]) (D{sub 95%} CTV: 60.6 vs 55.2, respectively; P=.001), and better CTV homogeneity (D{sub 5%}-D{sub 95%} CTV: 10.3 vs 17.7, resspectively; P=.002) in the face of uncertainties. Wit