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Chen ZJ, Li XA, Brenner DJ, Hellebust TP, Hoskin P, Joiner MC, Kirisits C, Nath R, Rivard MJ, Thomadsen BR, Zaider M. AAPM Task Group Report 267: A joint AAPM GEC-ESTRO report on biophysical models and tools for the planning and evaluation of brachytherapy. Med Phys 2024; 51:3850-3923. [PMID: 38721942 DOI: 10.1002/mp.17062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/28/2024] [Accepted: 03/08/2024] [Indexed: 06/05/2024] Open
Abstract
Brachytherapy utilizes a multitude of radioactive sources and treatment techniques that often exhibit widely different spatial and temporal dose delivery patterns. Biophysical models, capable of modeling the key interacting effects of dose delivery patterns with the underlying cellular processes of the irradiated tissues, can be a potentially useful tool for elucidating the radiobiological effects of complex brachytherapy dose delivery patterns and for comparing their relative clinical effectiveness. While the biophysical models have been used largely in research settings by experts, it has also been used increasingly by clinical medical physicists over the last two decades. A good understanding of the potentials and limitations of the biophysical models and their intended use is critically important in the widespread use of these models. To facilitate meaningful and consistent use of biophysical models in brachytherapy, Task Group 267 (TG-267) was formed jointly with the American Association of Physics in Medicine (AAPM) and The Groupe Européen de Curiethérapie and the European Society for Radiotherapy & Oncology (GEC-ESTRO) to review the existing biophysical models, model parameters, and their use in selected brachytherapy modalities and to develop practice guidelines for clinical medical physicists regarding the selection, use, and interpretation of biophysical models. The report provides an overview of the clinical background and the rationale for the development of biophysical models in radiation oncology and, particularly, in brachytherapy; a summary of the results of literature review of the existing biophysical models that have been used in brachytherapy; a focused discussion of the applications of relevant biophysical models for five selected brachytherapy modalities; and the task group recommendations on the use, reporting, and implementation of biophysical models for brachytherapy treatment planning and evaluation. The report concludes with discussions on the challenges and opportunities in using biophysical models for brachytherapy and with an outlook for future developments.
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Affiliation(s)
- Zhe Jay Chen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - X Allen Li
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - David J Brenner
- Center for Radiological Research, Columbia University Medical Center, New York, New York, USA
| | - Taran P Hellebust
- Department of Oncology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Peter Hoskin
- Mount Vernon Cancer Center, Mount Vernon Hospital, Northwood, UK
- University of Manchester, Manchester, UK
| | - Michael C Joiner
- Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Christian Kirisits
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Ravinder Nath
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Mark J Rivard
- Department of Radiation Oncology, Brown University School of Medicine, Providence, Rhode Island, USA
| | - Bruce R Thomadsen
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA
| | - Marco Zaider
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
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Semeniuk O, Yu E, Rivard MJ. Current and Emerging Radiotherapy Options for Uveal Melanoma. Cancers (Basel) 2024; 16:1074. [PMID: 38473430 DOI: 10.3390/cancers16051074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/14/2024] Open
Abstract
What treatment options are there for patients having uveal melanoma? A randomized, prospective, multi-institutional clinical trial (COMS) showed no difference in survival between brachytherapy and enucleation for medium-sized lesions. With the obvious benefit of retaining the eye, brachytherapy has flourished and many different approaches have been developed such as low-dose-rate sources using alternate low-energy photon-emitting radionuclides, different plaque designs and seed-loading techniques, high-dose-rate brachytherapy sources and applicators, and low- and high-dose-rate beta-emitting sources and applicators. There also have been developments of other radiation modalities like external-beam radiotherapy using linear accelerators with high-energy photons, particle accelerators for protons, and gamma stereotactic radiosurgery. This article examines the dosimetric properties, targeting capabilities, and outcomes of these approaches. The several modalities examined herein have differing attributes and it may be that no single approach would be considered optimal for all patients and all lesion characteristics.
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Affiliation(s)
- Oleksii Semeniuk
- Department of Radiation Oncology, Warren Alpert Medical School, Brown University and Rhode Island Hospital, Providence, RI 02903, USA
| | - Esther Yu
- Department of Radiation Oncology, Warren Alpert Medical School, Brown University and Rhode Island Hospital, Providence, RI 02903, USA
| | - Mark J Rivard
- Department of Radiation Oncology, Warren Alpert Medical School, Brown University and Rhode Island Hospital, Providence, RI 02903, USA
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Bakshi AK, Shrivastava V, Chattaraj A, Samuel K, Palani Selvam T, Sapra BK, Sinharoy P, Banerjee D, Sugilala G, Manohar S, Kaushik CP. Surface dose rate variations in planar and curved geometries of 106Ru/ 106Rh plaque sources for ocular tumors. Phys Med 2021; 89:200-209. [PMID: 34399207 DOI: 10.1016/j.ejmp.2021.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 07/31/2021] [Accepted: 08/02/2021] [Indexed: 11/19/2022] Open
Abstract
PURPOSE Investigation of surface dose rate variation with respect to the source configuration of 106Ru/106Rh eye plaque. To explore an alternate way to determine activity of brachytherapy plaques. METHODS The surface dose rates of 106Ru/106Rh plaque developed indigenously were measured by extrapolation chamber. To rule out possibility of any error in the activity distribution and quantity, same source was used in two different configurations namely planar and curved. EBT3 Gafchromic film was used for determination of uniformity in activity. Monte Carlo-based Codes EGSnrc and FLUKA were used to calculate dose rate in tissue, percentage depth dose and for determination of activity. Parameters and correction factors were estimated using simulations. RESULTS The measured reference absorbed dose rates for planar and curved 106Ru/106Rh eye plaques are found to be 589 ± 29 mGy/h and 560 ± 28 mGy/h, respectively. The difference in the reference absorbed dose rate of curved eye plaque is about ~5% as compared to planar configuration. The FLUKA-calculated dose values are almost independent of cavity length of the extrapolation chamber for both eye plaques. The FLUKA-based dose rates per μCi 106Ru/106Rh are about 17.28 ± 0.08 mGy/h and 16.48 ± 0.06 mGy/h, respectively for planar and curved eye plaques which match well with the measurements. The calculated activities for planar and curved eye plaques are 34.08 μCi and 33.98 μCi, respectively. CONCLUSIONS Surface dose rates for a prototype 106Ru/106Rh eye plaque with different configurations were estimated using simulations and measured experimentally. An alternate way to determine activity of beta-gamma brachytherapy plaque has been proposed.
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Affiliation(s)
- A K Bakshi
- Radiological Physics & Advisory Division, India; Homi Bhabha National Institute, Mumbai 400 094, India.
| | | | | | | | - T Palani Selvam
- Radiological Physics & Advisory Division, India; Homi Bhabha National Institute, Mumbai 400 094, India
| | - B K Sapra
- Radiological Physics & Advisory Division, India; Homi Bhabha National Institute, Mumbai 400 094, India
| | - Prithwish Sinharoy
- Nuclear Recycle Group, Bhabha Atomic Research Centre, Mumbai 400 085, India; Homi Bhabha National Institute, Mumbai 400 094, India
| | - Dayamoy Banerjee
- Nuclear Recycle Group, Bhabha Atomic Research Centre, Mumbai 400 085, India; Homi Bhabha National Institute, Mumbai 400 094, India
| | - G Sugilala
- Nuclear Recycle Group, Bhabha Atomic Research Centre, Mumbai 400 085, India; Homi Bhabha National Institute, Mumbai 400 094, India
| | - Smitha Manohar
- Radiological Physics & Advisory Division, India; Nuclear Recycle Group, Bhabha Atomic Research Centre, Mumbai 400 085, India; Homi Bhabha National Institute, Mumbai 400 094, India
| | - C P Kaushik
- Nuclear Recycle Group, Bhabha Atomic Research Centre, Mumbai 400 085, India; Homi Bhabha National Institute, Mumbai 400 094, India
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Deufel CL, Dalvin LA, Qian J, Vaishnav B, Cutsinger JM, Wittich MN, Petersen IA. How to design, fabricate, and validate a customized COMS-style eye plaque: Illustrated with a narrow-slotted plaque example. Brachytherapy 2021; 20:1235-1244. [PMID: 34217602 DOI: 10.1016/j.brachy.2021.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/09/2021] [Accepted: 04/08/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE A customized Collaborative Ocular Melanoma Study (COMS)-style eye plaque may provide superior dosimetric coverage compared with standard models for certain intraocular tumor locations and shapes. This work provides a recipe for developing and validating such customized plaques. METHODS AND MATERIALS The concept-into-clinical treatment process for a customized COMS-style eye plaque begins with a CAD model design that meets the specifications of the radiation oncologist and surgeon based on magnetic resonance, ultrasound, and clinical measurements, as well as a TG-43 hybrid heterogeneity-corrected dose prediction to model the dose distribution. Next, a 3D printed plastic prototype is created and reviewed. After design approval, a Modulay plaque is commercially fabricated. Quality assurance (QA) is subsequently performed to verify the physical measurements of the Modulay and Silastic and also includes dosimetric measurement of the calibration, depth dose, and dose profiles. Sterilization instructions are provided by the commercial fabricator. This customization procedure and QA methodology is demonstrated with a narrow-slotted plaque that was recently constructed for the treatment of a circumpapillary (e.g., surrounding the optic disk) ocular tumor. RESULTS The production of a customized COMS-style eye plaque is a multistep process. Dosimetric modeling is recommended to ensure that the design will meet the patient's needs, and QA is essential to confirm that the plaque has the proper dimensions and dose distribution. The customized narrow-slotted plaque presented herein was successfully implemented in the clinic, and provided superior dose coverage of juxtapapillary and circumpapillary tumors compared with standard or notched COMS-style plaques. Plaque development required approximately 30 h of physicist time and a fabrication cost of $1500. CONCLUSION Customized eye plaques may be used to treat intraocular tumors that cannot be adequately managed with standard models. The procedure by which a customized COMS-style plaque may be designed, fabricated, and validated was presented along with a clinical example.
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Affiliation(s)
| | | | - Jing Qian
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN
| | - Birjoo Vaishnav
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN
| | | | | | - Ivy A Petersen
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN
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Studenski MT, Markoe A, Samuels SE, Correa ZM, Bossart E, Harbour JW. Comprehensive assessment of the effect of eye plaque tilt on tumor dosimetry. Brachytherapy 2021; 20:1289-1295. [PMID: 34193361 DOI: 10.1016/j.brachy.2021.05.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/28/2021] [Accepted: 05/23/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE Tilting of the posterior plaque margin during eye plaque brachytherapy can lead to tumor underdosing and increased risk of local recurrence. We performed a quantitative analysis of the dosimetric effects of plaque tilt as a function of tumor position, basal dimension, height and plaque type using 3D treatment planning software. MATERIALS AND METHODS Posterior and anterior tumors with largest basal dimensions of 6, 12 and 18 mm and heights of 4, 7 and 10 mm were modeled. Both Eye Physics and COMS plaques were simulated and uniformly loaded. Plans were normalized to 85 Gy at the tumor apex. Posterior plaque tilts of 1, 2, 3 and 4 mm were simulated. RESULTS Volumetric coverage is more sensitive to tilt than the area coverage. Wide, flat tumors are more susceptible to tilt. Apical dose changed significantly as a function of tumor height and diameter. No other parameter exhibited significant differences. Posterior tumors are slightly more susceptible to tilt due to the use of notched plaques. Plaque type does not significantly alter the effect of plaque tilt. CONCLUSIONS Wide, flat tumors are the most susceptible to plaque tilt. Tumor location or plaque type does not have a significant effect on dosimetry changes from plaque tilt. Robust clinical procedures such as the use of mattress sutures, pre- and post-implant ultrasound and post-implant dosimetry can all mitigate the risk associated with plaque tilt.
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Affiliation(s)
- Matthew T Studenski
- Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL.
| | - Arnold Markoe
- Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL
| | - Stuart E Samuels
- Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL
| | - Zelia M Correa
- Bascom Palmer Eye Institute, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL
| | - Elizabeth Bossart
- Department of Radiation Oncology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL
| | - J William Harbour
- Bascom Palmer Eye Institute, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL
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Miguel D, Saornil MA, de Frutos JM, García-Álvarez C, Alonso P, Diezhandino P. Regression of posterior uveal melanoma following iodine-125 plaque radiotherapy based on pre-treatment tumor apical height. J Contemp Brachytherapy 2021; 13:117-125. [PMID: 33897784 PMCID: PMC8060957 DOI: 10.5114/jcb.2021.105278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 01/18/2021] [Indexed: 11/18/2022] Open
Abstract
PURPOSE The aim of this study was to analyze regression rates and local control of uveal melanoma patients treated with iodine-125 ( 125I) brachytherapy based on initial tumor apical height. MATERIAL AND METHODS Patients treated in a single institution from January 1st, 1996 to 2019 with 125I plaques (ROPES and COMS) for uveal melanoma were included in this study. Patients treated with brachytherapy for iris and those treated with transpupillary thermotherapy prior to brachytherapy were excluded. The sample was classified into 4 categories depending on initial apical tumor height (h0), i.e., h0 ≤ 2.5 (small), 2.5 < h0 ≤ 6.25 (small-medium), 6.25 < h0 ≤ 10 (medium-large), and h0 > 10 mm (large). Percentage of original tumor apical height (Δh) was collected during follow-ups. Patterns of regression were evaluated using linear least squares adjustments. Multivariable Cox regression were performed. RESULTS In total, 305 patients met the inclusion criteria, and 27, 166, 100, and 13 were considered for small, small-medium, medium-large, and large categories, respectively. Median follow-up was 82.4, 56.8, 76.1, 89.1, and 100.1 months for the entire cohort and each sub-group, respectively. Pattern of decrease when h0 ≤ 2.5 mm was not detectable. For the rest sub-groups, changes in height could be fitted using functional form: Δh (T) = ae-bT + c, R 2 ≥ 0.97. Multivariate Cox analysis factors predictive of local control failure revealed a hazard ratio (HR) of 6.1 (95% CI: 0.7-58.2%, p = 0.05) for patients who remained similar sized after treatment for small-medium tumors. For the rest sub-groups, Cox analysis did not indicate statistical significance in any single variable. CONCLUSIONS Height changes can be modeled by a negative exponential function for the first 7 years after treatment depending on the initial height, except for those less than 2.5 mm. Non-responding small-medium tumors multiply by 6 the probability of failure in local control.
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Affiliation(s)
- David Miguel
- Intraocular Tumors Unit, Valladolid University Hospital, Valladolid, Spain
| | | | | | | | - Pilar Alonso
- Intraocular Tumors Unit, Valladolid University Hospital, Valladolid, Spain
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Deufel CL, McCauley Cutsinger S, Corbin KS, Dalvin LA, Petersen IA. EyeDose: An open-source tool for using published Monte Carlo results to estimate the radiation dose delivered to the tumor and critical ocular structures for 125I Collaborative Ocular Melanoma Study eye plaques. Brachytherapy 2020; 20:189-199. [PMID: 33187821 DOI: 10.1016/j.brachy.2020.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/07/2020] [Accepted: 09/11/2020] [Indexed: 11/24/2022]
Abstract
PURPOSE Radiation side effects and visual outcome for uveal melanoma patients managed with plaque radiotherapy are dependent on the radiation dose administered to the tumor and nearby healthy tissues. We have developed an open-source software tool, EyeDose, to simplify and standardize tumor and critical structure dose reporting for Collaborative Ocular Melanoma Study eye plaques. METHODS AND MATERIALS EyeDose is a MATLAB-based program that calculates point dose and volume dose metrics for standard models of the tumor and critical ocular structures. It uses published three-dimensional dose distributions for eye plaques, calculated with Monte Carlo methods, which are oriented with respect to the eye using the tumor's position on a fundus diagram. A standard model for the ocular structures was created using published measurements and patient CT scans. EyeDose reports radiation statistics for the fovea, optic disc, lens, lacrimal gland, retina, and tumor. The dosimetric margin for implant placement uncertainty is also calculated. RESULTS EyeDose calculations were validated against previously published Monte Carlo results for eight different tumor positions, including the dose to the fovea, optic disc, lacrimal gland, lens, and along the central axis. EyeDose accepts a spreadsheet input for rapidly processing large retrospective patient data sets, with an average run time of <40 s per patient. EyeDose is published as an open-source tool for easy adaptation at different institutions. CONCLUSIONS EyeDose calculates radiation statistics for Collaborative Ocular Melanoma Study eye plaque patients with Monte Carlo accuracy and without a treatment planning system. EyeDose streamlines data collection for large retrospective studies and can also be used prospectively to assess plaque applicability.
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Affiliation(s)
| | | | | | | | - Ivy A Petersen
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN
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Abstract
The purpose of this study was to review the limitations of dose calculation formalisms for photon-emitting brachytherapy sources based on the American Association of Physicists in Medicine (AAPM) Task Group No. 43 (TG-43) report and to provide recommendations to transition to model-based dose calculation algorithms. Additionally, an overview of these algorithms and approaches is presented. The influence of tissue and seed/applicator heterogeneities on brachytherapy dose distributions for breast, gynecologic, head and neck, rectum, and prostate cancers as well as eye plaques and electronic brachytherapy treatments were investigated by comparing dose calculations based on the TG-43 formalism and model-based dose calculation algorithms.
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Thomson RM, Furutani KM, Kaulich TW, Mourtada F, Rivard MJ, Soares CG, Vanneste FM, Melhus CS. AAPM recommendations on medical physics practices for ocular plaque brachytherapy: Report of task group 221. Med Phys 2020; 47:e92-e124. [PMID: 31883269 DOI: 10.1002/mp.13996] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/12/2019] [Accepted: 12/23/2019] [Indexed: 12/14/2022] Open
Abstract
The American Association of Physicists in Medicine (AAPM) formed Task Group 221 (TG-221) to discuss a generalized commissioning process, quality management considerations, and clinical physics practice standards for ocular plaque brachytherapy. The purpose of this report is also, in part, to aid the clinician to implement recommendations of the AAPM TG-129 report, which placed emphasis on dosimetric considerations for ocular brachytherapy applicators used in the Collaborative Ocular Melanoma Study (COMS). This report is intended to assist medical physicists in establishing a new ocular brachytherapy program and, for existing programs, in reviewing and updating clinical practices. The report scope includes photon- and beta-emitting sources and source:applicator combinations. Dosimetric studies for photon and beta sources are reviewed to summarize the salient issues and provide references for additional study. The components of an ocular plaque brachytherapy quality management program are discussed, including radiation safety considerations, source calibration methodology, applicator commissioning, imaging quality assurance tests for treatment planning, treatment planning strategies, and treatment planning system commissioning. Finally, specific guidelines for commissioning an ocular plaque brachytherapy program, clinical physics practice standards in ocular plaque brachytherapy, and other areas reflecting the need for specialized treatment planning systems, measurement phantoms, and detectors (among other topics) to support the clinical practice of ocular brachytherapy are presented. Expected future advances and developments for ocular brachytherapy are discussed.
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Affiliation(s)
- Rowan M Thomson
- Carleton Laboratory for Radiotherapy Physics, Physics Department, Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - Keith M Furutani
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Theodor W Kaulich
- Department of Medical Physics, University of Tübingen, 72074, Tübingen, Germany
| | - Firas Mourtada
- Department of Radiation Oncology, Christiana Care Hospital, Newark, DE, 19713, USA
| | - Mark J Rivard
- Department of Radiation Oncology, Warren Alpert Medical School of Brown University, Providence, RI, 02903, USA
| | | | | | - Christopher S Melhus
- Department of Radiation Oncology, Tufts University School of Medicine, Boston, MA, 02111, USA
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Binder C, Mruthyunjaya P, Schefler AC, Seider MI, Crilly R, Hung A, Meltsner S, Mowery Y, Kirsch DG, Teh BS, Jennelle RLS, Studenski MT, Liu W, Lee C, Hayman JA, Kastner B, Hadsell M, Skalet AH. Practice Patterns for the Treatment of Uveal Melanoma with Iodine-125 Plaque Brachytherapy: Ocular Oncology Study Consortium Report 5. Ocul Oncol Pathol 2019; 6:210-218. [PMID: 32509767 DOI: 10.1159/000504312] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/06/2019] [Indexed: 11/19/2022] Open
Abstract
Background Treatment planning for I-125 plaque therapy for uveal melanoma has advanced significantly since the Collaborative Ocular Melanoma Study trial, with more widely available image-guided planning and improved dosimetry. Objective We evaluated real-world practice patterns for I-125 plaque brachytherapy in the United States by studying practice patterns at centers that comprise the Ocular Oncology Study Consortium (OOSC). Methods The OOSC database and responses to a treatment practice survey were evaluated. The database contains treatment information from 9 institutions. Patients included in the database were treated between 2010 and 2014. The survey was conducted in 2018 and current treatment planning methods and prescriptions were queried. Results Examination of the OOSC database revealed that average doses to critical structures were highly consistent, with the exception of one institution. Survey responses indicated that most centers followed published guidelines regarding dose and prescription point. Dose rate ranged from 51 to 118 cGy/h. As of 2018, most institutions use pre-loaded plaques and fundus photographs and/or computed tomography or magnetic resonance imaging in planning. Conclusions While there were differences in dosimetric practices, overall agreement in plaque brachytherapy practices was high among OOSC institutions. Clinical margins and planning systems were similar among institutions, while prescription dose, dose rates, and dosimetry varied.
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Affiliation(s)
- Christina Binder
- Department of Radiation Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Prithvi Mruthyunjaya
- Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, California, USA.,Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, USA
| | | | - Michael I Seider
- The Permanente Medical Group, San Francisco, California, USA.,Department of Ophthalmology, University of California, San Francisco, California, USA
| | - Richard Crilly
- Department of Radiation Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Arthur Hung
- Department of Radiation Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Sheridan Meltsner
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, USA
| | - Yvonne Mowery
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, USA
| | - David G Kirsch
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, USA
| | - Bin S Teh
- Department of Radiation Oncology, Houston Methodist Cancer Center, Houston, Texas, USA
| | - Richard L S Jennelle
- Department of Radiation Oncology, University of Southern California Medical Center, Los Angeles, California, USA
| | - Matthew T Studenski
- Department of Radiation Oncology/Sylvester Comprehensive Cancer Center, University of Miami, Miami, Florida, USA
| | - Wu Liu
- Department of Radiation Oncology, Stanford University, Palo Alto, California, USA.,Department of Therapeutic Radiology, Yale University and Yale-New haven Hospital, New Haven, Connecticut, USA
| | - Choonik Lee
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA
| | - James A Hayman
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, USA
| | - Brian Kastner
- Radiation Oncology Centers, PC, Spectrum Health, Grand Rapids, Michigan, USA
| | - Michael Hadsell
- Department of Radiation Oncology, Porter Adventist, Centura Health, Denver, Colorado, USA
| | - Alison H Skalet
- Department of Radiation Medicine, Oregon Health and Science University, Portland, Oregon, USA.,Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, USA
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Experimental validation of a new COMS-like 24 mm eye plaque for the treatment of large ocular melanoma tumors. Brachytherapy 2019; 18:890-897. [DOI: 10.1016/j.brachy.2019.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/19/2019] [Accepted: 07/24/2019] [Indexed: 11/19/2022]
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12
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Delivered dose changes in COMS plaque-based ocular brachytherapy arising from vitrectomy with silicone oil replacement. Brachytherapy 2019; 18:668-674. [PMID: 31272841 DOI: 10.1016/j.brachy.2019.05.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/24/2019] [Accepted: 05/31/2019] [Indexed: 12/30/2022]
Abstract
PURPOSE The purpose of the study was to determine dosimetric effects of performing concurrent I-125 Collaborative Ocular Melanoma Study plaque brachytherapy and vitrectomy with replacement using silicone oil, previously shown to be a means of shielding uninvolved parts of the eye. METHODS AND MATERIALS Monte Carlo simulations using MCNP6 were performed to compare the dosimetry with all eye materials assigned as water, and for the vitreous (excluding the tumor), composed of polydimethylsiloxane oil for three generic, one large tumor, and two patient geometry scenarios. Dose was scored at the tumor apex, along the sclera, and within a 3D grid encompassing the eye. The assessed patient cases included vitrectomies to treat intraocular pathologies; not to enhance attenuation/shielding. RESULTS The doses along the sclera and for the entire eye were decreased when the silicone oil replaced the vitreal fluid, with a maximum decrease at the opposite sclera of 63%. Yet, absolute changes in dose to critical structures were often small and likely not clinically significant. The dose at the tumor apex was decreased by 3.1-9.4%. Dose was also decreased at the edges of the tumor because of decreased backscatter at the tumor-oil interface. CONCLUSIONS Concurrent silicone vitrectomy was found to reduce total radiation dose to the eye. Based on current radiation retinopathy predictive models, the evaluation of the absolute doses revealed only a subset of patients in which a clinically significant difference in outcomes is expected. Furthermore, the presence of the silicone oil decreased dose to the tumor edges, indicating that the tumor could be underdosed if the oil is unaccounted for.
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13
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Treatment planning considerations for 125I eye plaque brachytherapy. J Contemp Brachytherapy 2019; 11:280-284. [PMID: 31435435 PMCID: PMC6701382 DOI: 10.5114/jcb.2019.86370] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 04/10/2019] [Indexed: 12/21/2022] Open
Abstract
Effective cancer brachytherapy requires a treatment plan that delivers high-dose to tumor, while minimizing the dose to critical normal tissues. Therefore, an accurate knowledge of the sources and magnitude of the techniques is essential for producing robust and well optimized-plans. The purpose of this technical note is to establish general procedures and strategies for optimization and customization of the plaques loaded with radioactive seeds, particularly focusing on the definition of useful tactics to limit high doses to organs at risk and adapt the treatment time to the necessity of institution.
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Yan H, Ma X, Sun W, Mendez S, Stryker S, Starr-Baier S, Delliturri G, Zhu D, Nath R, Chen Z, Roberts K, MacDonald CA, Liu W. Monte Carlo dosimetry modeling of focused kV x-ray radiotherapy of eye diseases with potential nanoparticle dose enhancement. Med Phys 2018; 45:4720-4733. [PMID: 30133705 DOI: 10.1002/mp.13144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 08/14/2018] [Accepted: 08/14/2018] [Indexed: 12/18/2022] Open
Abstract
PURPOSE Eye plaque brachytherapy is the most common approach for intraocular cancer treatment. It is, however, invasive and subject to large setup uncertainty due to the surgical operation. We propose a novel-focused kV x-ray technique with potential nanoparticle (NP) enhancement and evaluate its application in treating choroidal melanoma and iris melanoma by Monte Carlo (MC) dosimetry modeling. METHODS A polycapillary x-ray lens was used to focus 45 kVp x rays to achieve pinpoint accuracy of dose delivery to small tumors near critical structures. In addition to allowing for beam focusing, the use of kV x rays takes advantage of the strong photoelectric absorption of metallic NPs in that energy regime and hence strong radiosensitization. We constructed an MC simulation program that takes into account the x-ray optic modeling and used GEANT4 for dosimetric calculation. Extensive phantom measurements using a prototype-focused x-ray system were carried out. The MC simulation of simple geometry phantom irradiation was first compared to measurements to verify the x-ray optic lens modeling in conjunction with the Geant4 dosimetric calculation. To simulate tumor treatment, a geometric eye model and two tumor models were constructed. Dose distributions of the simulated treatments were then calculated. NP radiosensitization was also simulated for two concentrations of 2 nm gold NP (AuNP) uniformly distributed in the tumor. RESULTS The MC-simulated full width at half maximum (FWHM) and central-axis depth dose of the focused kV x-ray beam match those measured on EBT3 films within ~10% around the depth of focus of the beam. Dose distributions of the simulated ocular tumor treatments show that focused x-ray beams can concentrate the high-dose region in or close to the tumor plus margin. For the simulated posterior choroidal tumor treatment, with sufficient tumor coverage, the doses to the optic disc and fovea are substantially reduced with focused x-ray therapy compared to eye plaque treatment (3.8 vs 39.8 Gy and 11.1 vs 53.8 Gy, respectively). The eye plaque treatment was calculated using an Eye Physics plaque with I-125 seeds under TG43 assumption. For the energy spectrum used in this study, the average simulated dose enhancement ratios (DERs) are roughly 2.1 and 1.1 for 1.0% and 0.1% AuNP mass concentration in the tumor, respectively. CONCLUSION Compared to eye plaque brachytherapy, the proposed focused kV x-ray technique is noninvasive and shows great advantage in sparing healthy critical organs without sacrificing the tumor control. The NP radiation dose enhancement is considerable at our proposed kV range even with a low NP concentration in the tumor, providing better critical structure protection and more flexibility for treatment planning.
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Affiliation(s)
- Huagang Yan
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, 06510, USA.,School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China
| | - Xiangyu Ma
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China
| | - Weiyuan Sun
- Department of Physics, University at Albany, SUNY, Albany, NY, 12222, USA
| | - Stacy Mendez
- Department of Physics, Fairfield University, Fairfield, CT, 06824, USA
| | - Stefan Stryker
- Department of Physics, West Kentucky University, Bowling Green, KY, 42101, USA
| | - Sean Starr-Baier
- Department of Physics, University at Albany, SUNY, Albany, NY, 12222, USA
| | | | - Dengsong Zhu
- Department of Physics, East Carolina University, Greenville, NC, 27858, USA
| | - Ravinder Nath
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, 06510, USA
| | - Zhe Chen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, 06510, USA
| | - Kenneth Roberts
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, 06510, USA
| | | | - Wu Liu
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, 06510, USA
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Miguel D, de Frutos-Baraja JM, López-Lara F, Saornil MA, García-Álvarez C, Alonso P, Diezhandino P. Radiobiological doses, tumor, and treatment features influence on local control, enucleation rates, and survival after epiescleral brachytherapy. A 20-year retrospective analysis from a single-institution: part I. J Contemp Brachytherapy 2018; 10:337-346. [PMID: 30237817 PMCID: PMC6142652 DOI: 10.5114/jcb.2018.77849] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 07/25/2018] [Indexed: 01/12/2023] Open
Abstract
PURPOSE To assess influence of the radiobiological doses, tumor, and treatment features on local control, enucleation rates, overall and disease-specific survival rates after brachytherapy for posterior uveal melanoma. MATERIAL AND METHODS Local control, enucleation, overall and disease-specific survival rates were evaluated on the base of 243 patients from 1996 through 2016, using plaques loaded with iodine sources. Clinical and radiotherapy data were extracted from a dedicated prospective database. Biologically effective dose (BED) was included in survival analysis using Kaplan-Meier and Cox regressions. The 3-, 5-, 10-, and 15-year relative survival rates were estimated, and univariate/multivariate regression models were constructed for predictive factors of each item. Hazard ratio (HR) and confidence interval at 95% (CI) were determined. RESULTS The median follow-up was 73.9 months (range, 3-202 months). Cumulative probabilities of survival by Kaplan-Meier analysis at 3, 5, 10 and 15 years were respectively: 96%, 94%, 93%, and 87%, for local control; 93%, 88%, 81%, and 73% for globe preservation; 98%, 93%, 84%, and 73% for overall survival, and 98%, 96%, 92%, and 87% for disease-specific survival. By multivariate analysis, we concluded variables as significant: for local control failure - the longest basal diameter and the juxtapapillary location; for globe preservation failure - the longest basal dimension, the mushroom shape, the location in ciliary body, and the dose to the foveola; for disease-specific survival - the longest basal dimension. Some radiobiological doses were significant in univariate models but not in multivariate ones for the items studied. CONCLUSIONS The results show as predictive factors of local control, enucleation, and disease-specific survival rates those related with the features of the tumor, specifically the longest basal dimension. There is no clear relation between radiobiological doses or treatment parameters in patients after brachytherapy.
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Affiliation(s)
- David Miguel
- Intraocular Tumor Unit, Hospital Universitario de Valladolid, Valladolid
- University of Valladolid, Valladolid, Spain
| | - Jesús María de Frutos-Baraja
- Intraocular Tumor Unit, Hospital Universitario de Valladolid, Valladolid
- University of Valladolid, Valladolid, Spain
| | - Francisco López-Lara
- Intraocular Tumor Unit, Hospital Universitario de Valladolid, Valladolid
- University of Valladolid, Valladolid, Spain
| | - María Antonia Saornil
- Intraocular Tumor Unit, Hospital Universitario de Valladolid, Valladolid
- University of Valladolid, Valladolid, Spain
| | - Ciro García-Álvarez
- Intraocular Tumor Unit, Hospital Universitario de Valladolid, Valladolid
- University of Valladolid, Valladolid, Spain
| | - Pilar Alonso
- Intraocular Tumor Unit, Hospital Universitario de Valladolid, Valladolid
- University of Valladolid, Valladolid, Spain
| | - Patricia Diezhandino
- Intraocular Tumor Unit, Hospital Universitario de Valladolid, Valladolid
- University of Valladolid, Valladolid, Spain
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Visual outcome after posterior uveal melanoma episcleral brachytherapy including radiobiological doses. J Contemp Brachytherapy 2018; 10:123-131. [PMID: 29789761 PMCID: PMC5961527 DOI: 10.5114/jcb.2018.75597] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/10/2018] [Indexed: 12/13/2022] Open
Abstract
Purpose To assess the long-term influence of radiobiological doses in the evolution of visual acuity (VA) in patients with uveal melanoma treated by episcleral brachytherapy. Material and methods Visual acuity was evaluated prospectively from a case series of 243 patients in 2016 treated with 125I. Data analysis was applied to trend VA outcome and find the accurate best-fit line. Biologically effective dose (BED) was included in survival analysis with the use of Kaplan-Meier and Cox regressions. Hazard ratio (HR) and confidence interval at 95% (CI) were determined. Variables statistically significant were analyzed and compared by log-rank tests. Results The median follow-up was 74.2 months (range, 3-223). Exponential regression shows a 25% reduction and 50% in visual acuity score (VAS) scale for 5 and 27.8 months, respectively. Cumulative probabilities of survival analysis were 57%, 42%, 27%, and 23% at 3, 5, 10, and 15 years, respectively. Multivariable analysis found tumor height (HR = 1.18, 95% CI: 1.07-1.29), applicator size (HR = 1.22, 95% CI: 1.08-1.36), juxtapapillary localization (HR = 1.70, 95% CI: 1.01-2.84), and dose to foveola (HR = 1.01, 95% CI: 1.00-1.01) significantly associated with VA loss. Log-rank tests were significant for all those variables. BED has a strong influence in univariate model, but not statistically significant in the multivariate one. Conclusions Visual acuity changes can be modeled by an exponential function for the first 5 years after treatment. No relation between VA loss and BED has been found; nevertheless, apical height, plaque size, juxtapapillary localization, and dose to fovea were found as statistical significant variables.
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Zoberi JE, Garcia-Ramirez J, Hedrick S, Rodriguez V, Bertelsman CG, Mackey S, Hu Y, Gach HM, Rao PK, Grigsby PW. MRI-based treatment planning and dose delivery verification for intraocular melanoma brachytherapy. Brachytherapy 2017; 17:31-39. [PMID: 28818442 DOI: 10.1016/j.brachy.2017.07.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 06/30/2017] [Accepted: 07/14/2017] [Indexed: 12/18/2022]
Abstract
PURPOSE Episcleral plaque brachytherapy (EPB) planning is conventionally based on approximations of the implant geometry with no volumetric imaging following plaque implantation. We have developed an MRI-based technique for EPB treatment planning and dose delivery verification based on the actual patient-specific geometry. METHODS AND MATERIALS MR images of 6 patients, prescribed 85 Gy over 96 hours from Collaborative Ocular Melanoma Study-based EPB, were acquired before and after implantation. Preimplant and postimplant scans were used to generate "preplans" and "postplans", respectively. In the preplans, a digital plaque model was positioned relative to the tumor, sclera, and nerve. In the postplans, the same plaque model was positioned based on the imaged plaque. Plaque position, point doses, percentage of tumor volume receiving 85 Gy (V100), and dose to 100% of tumor volume (Dmin) were compared between preplans and postplans. All isodose plans were computed using TG-43 formalism with no heterogeneity corrections. RESULTS Shifts and tilts of the plaque ranged from 1.4 to 8.6 mm and 1.0 to 3.8 mm, respectively. V100 was ≥97% for 4 patients. Dmin for preplans and postplans ranged from 83 to 118 Gy and 45 to 110 Gy, respectively. Point doses for tumor apex and base were all found to decrease from the preimplant to the postimplant plan, with mean differences of 16.7 ± 8.6% and 30.5 ± 11.3%, respectively. CONCLUSIONS By implementing MRI for EPB, we eliminate reliance on approximations of the eye and tumor shape and the assumption of idealized plaque placement. With MRI, one can perform preimplant as well as postimplant imaging, facilitating EPB treatment planning based on the actual patient-specific geometry and dose-delivery verification based on the imaged plaque position.
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Affiliation(s)
| | - Jose Garcia-Ramirez
- Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, MO
| | | | - Vivian Rodriguez
- Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, MO
| | - Carol G Bertelsman
- Department of Radiation Oncology, Barnes Jewish Hospital, Saint Louis, MO
| | - Stacie Mackey
- Department of Radiation Oncology, Barnes Jewish Hospital, Saint Louis, MO
| | - Yanle Hu
- Department of Radiation Oncology, Mayo Clinic, Scottsdale, AZ
| | - H Michael Gach
- Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, MO; Department of Radiology, Washington University School of Medicine, Saint Louis, MO
| | - P Kumar Rao
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, MO
| | - Perry W Grigsby
- Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, MO
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INTERACTS (INTErventional Radiotherapy ACtive Teaching School) guidelines for quality assurance in choroidal melanoma interventional radiotherapy (brachytherapy) procedures. J Contemp Brachytherapy 2017; 9:287-295. [PMID: 28725254 PMCID: PMC5509988 DOI: 10.5114/jcb.2017.68761] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 06/23/2017] [Indexed: 12/13/2022] Open
Abstract
Eye plaque brachytherapy represents a safe and effective therapeutic approach for choroidal melanoma, combining clinical outcomes with an eye and visual preservation. As it represents a complex procedure, a specific quality assurance program is strongly suggested to improve patients and operators safety, and to reduce possible complications linked to surgical procedure and radiation exposure. The aim of this paper is to describe the INTERACTS (Interventional Radiotherapy Active Teaching School) guidelines for quality assurance in choroidal melanoma interventional radiotherapy (brachytherapy) used in our institution.
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Gorovets D, Gagne NL, Melhus CS. Dosimetric and radiobiologic comparison of 103Pd COMS plaque brachytherapy and Gamma Knife radiosurgery for choroidal melanoma. Brachytherapy 2017; 16:433-443. [PMID: 28161431 DOI: 10.1016/j.brachy.2016.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/16/2016] [Accepted: 12/17/2016] [Indexed: 12/18/2022]
Abstract
PURPOSE Plaque brachytherapy (BT) and Gamma Knife radiosurgery (GKRS) are highly conformal treatment options for choroidal melanoma. This study objectively compares physical dose and biologically effective dose (BED) distributions for these two modalities. METHODS AND MATERIALS Tumor and organ-at-risk (OAR) dose distributions from a CT-defined reference right eye were compared between 103Pd COMS (Collaborative Ocular Melanoma Study Group) plaques delivering 70 Gy (plaque heterogeneity corrected) over 120 h to the tumor apex and GKRS plans delivering 22 Gy to the 40% isodose line for a representative sample of clinically relevant choroidal melanoma locations and sizes. Tumor and OAR biologically effective dose-volume histograms were generated using consensus radiobiologic parameters and modality-specific BED equations. RESULTS Published institutional prescriptive practices generally lead to larger tumor and OAR physical doses from COMS BT vs. GKRS. Radiobiologic dose conversions, however, revealed variable BEDs. Medium and large tumors receive >1.3 times higher BEDs with COMS BT vs. GKRS. OAR BEDs have even greater dependence on tumor size, location, and treatment modality. For example, COMS BT maximum BEDs to the optic nerve are lower than from GKRS for large anterior and all posterior tumors but are higher for anterior small and medium tumors. CONCLUSIONS BT and GKRS for choroidal melanoma have different physical dose and BED distributions with potentially unique clinical consequences. Using published institutional prescriptive practices, neither modality is uniformly favored, although COMS BT delivers higher physical doses and BEDs to tumors. These results suggest that lowering the physical prescription dose for COMS BT to more closely match the BED of GKRS might maintain equivalent tumor control with less potential morbidity.
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Affiliation(s)
- Daniel Gorovets
- Department of Radiation Oncology, Tufts University School of Medicine, Boston, MA
| | - Nolan L Gagne
- Department of Radiation Oncology, Tufts University School of Medicine, Boston, MA
| | - Christopher S Melhus
- Department of Radiation Oncology, Tufts University School of Medicine, Boston, MA.
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Morrison H, Menon G, Larocque MP, Jans HS, Weis E, Sloboda RS. Delivered dose uncertainty analysis at the tumor apex for ocular brachytherapy. Med Phys 2016; 43:4891. [DOI: 10.1118/1.4959540] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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Ruthenium-106 brachytherapy for thick uveal melanoma: reappraisal of apex and base dose radiation and dose rate. J Contemp Brachytherapy 2016; 8:66-73. [PMID: 26985199 PMCID: PMC4793070 DOI: 10.5114/jcb.2016.57818] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/20/2016] [Indexed: 11/17/2022] Open
Abstract
Purpose To evaluate the outcomes of ruthenium-106 (106Ru) brachytherapy in terms of radiation parameters in patients with thick uveal melanomas. Material and methods Medical records of 51 patients with thick (thickness ≥ 7 mm and < 11 mm) uveal melanoma treated with 106Ru brachytherapy during a ten-year period were reviewed. Radiation parameters, tumor regression, best corrected visual acuity (BCVA), and treatment-related complications were assessed. Results Fifty one eyes of 51 consecutive patients including 25 men and 26 women with a mean age of 50.5 ± 15.2 years were enrolled. Patients were followed for 36.1 ± 26.5 months (mean ± SD). Mean radiation dose to tumor apex and to sclera were 71 (± 19.2) Gy and 1269 (± 168.2) Gy. Radiation dose rates to tumor apex and to sclera were 0.37 (± 0.14) Gy/h and 6.44 (± 1.50) Gy/h. Globe preservation was achieved in 82.4%. Preoperative mean tumor thickness of 8.1 (± 0.9) mm decreased to 4.5 (± 1.6) mm, 3.4 (± 1.4) mm, and 3.0 (± 1.46) mm at 12, 24, and 48 months after brachytherapy (p = 0.03). Four eyes that did not show regression after 6 months of brachytherapy were enucleated. Secondary enucleation was performed in 5 eyes because of tumor recurrence or neovascular glaucoma. Tumor recurrence was evident in 6 (11.8%) patients. Mean Log MAR (magnification requirement) visual acuity declined from 0.75 (± 0.63) to 0.94 (± 0.5) (p = 0.04). Best corrected visual acuity of 20/200 or worse was recorded in 37% of the patients at the time of diagnosis and 61.7% of the patients at last exam (p = 0.04). Non-proliferative and proliferative radiation-induced retinopathy was observed in 20 and 7 eyes. Conclusions Thick uveal melanomas are amenable to 106Ru brachytherapy with less than recommended apex radiation dose and dose rates.
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Gagne NL, Rivard MJ. COMS eye plaque brachytherapy dosimetric sensitivity to source photon energy and seed design. Appl Radiat Isot 2013; 79:62-6. [DOI: 10.1016/j.apradiso.2013.04.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/20/2013] [Accepted: 04/29/2013] [Indexed: 01/11/2023]
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Keeping an eye on the ring: COMS plaque loading optimization for improved dose conformity and homogeneity. J Contemp Brachytherapy 2013; 4:165-75. [PMID: 23346146 PMCID: PMC3551379 DOI: 10.5114/jcb.2012.30683] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 06/29/2012] [Accepted: 07/19/2012] [Indexed: 12/15/2022] Open
Abstract
PURPOSE To improve tumor dose conformity and homogeneity for COMS plaque brachytherapy by investigating the dosimetric effects of varying component source ring radionuclides and source strengths. MATERIAL AND METHODS The MCNP5 Monte Carlo (MC) radiation transport code was used to simulate plaque heterogeneity-corrected dose distributions for individually-activated source rings of 14, 16 and 18 mm diameter COMS plaques, populated with (103)Pd, (125)I and (131)Cs sources. Ellipsoidal tumors were contoured for each plaque size and MATLAB programming was developed to generate tumor dose distributions for all possible ring weighting and radionuclide permutations for a given plaque size and source strength resolution, assuming a 75 Gy apical prescription dose. These dose distributions were analyzed for conformity and homogeneity and compared to reference dose distributions from uniformly-loaded (125)I plaques. The most conformal and homogeneous dose distributions were reproduced within a reference eye environment to assess organ-at-risk (OAR) doses in the Pinnacle(3) treatment planning system (TPS). The gamma-index analysis method was used to quantitatively compare MC and TPS-generated dose distributions. RESULTS Concentrating > 97% of the total source strength in a single or pair of central (103)Pd seeds produced the most conformal dose distributions, with tumor basal doses a factor of 2-3 higher and OAR doses a factor of 2-3 lower than those of corresponding uniformly-loaded (125)I plaques. Concentrating 82-86% of the total source strength in peripherally-loaded (131)Cs seeds produced the most homogeneous dose distributions, with tumor basal doses 17-25% lower and OAR doses typically 20% higher than those of corresponding uniformly-loaded (125)I plaques. Gamma-index analysis found > 99% agreement between MC and TPS dose distributions. CONCLUSIONS A method was developed to select intra-plaque ring radionuclide compositions and source strengths to deliver more conformal and homogeneous tumor dose distributions than uniformly-loaded (125)I plaques. This method may support coordinated investigations of an appropriate clinical target for eye plaque brachytherapy.
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