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Mishra S, Selvam TP, Sahoo S, Saxena SK, Kumar Y, Sapra BK. Monte Carlo-based dosimetry of proposed bi-radionuclide ( 125I and 106Ru/ 106Rh) eye plaque: A feasibility study. Med Phys 2024. [PMID: 38935327 DOI: 10.1002/mp.17257] [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: 11/07/2023] [Revised: 05/16/2024] [Accepted: 06/03/2024] [Indexed: 06/28/2024] Open
Abstract
BACKGROUND Combining the sharp dose fall off feature of beta-emitting 106Ru/106Rh radionuclide with larger penetration depth feature of photon-emitting125I radionuclide in a bi-radionuclide plaque, prescribed dose to the tumor apex can be delivered while maintaining the tumor dose uniformity and sparing the organs at risk. The potential advantages of bi-radionuclide plaque could be of interest in context of ocular brachytherapy. PURPOSE The aim of the study is to evaluate the dosimetric advantages of a proposed bi-radionuclide plaque for two different designs, consisting of indigenous 125I seeds and 106Ru/106Rh plaque, using Monte Carlo technique. The study also explores the influence of other commercial 125I seed models and presence or absence of silastic/acrylic seed carrier on the calculated dose distributions. The study further included the calculation of depth dose distributions for the bi-radionuclide eye plaque for which experimental data are available. METHODS The proposed bi-radionuclide plaque consists of a 1.2-mm-thick silver (Ag) spherical shell with radius of curvature of 12.5 mm, 20 µm-thick-106Ru/106Rh encapsulated between 0.2 mm Ag disk, and a 0.1-mm-thick Ag window, and water-equivalent gel containing 12 symmetrically arranged 125I seeds. Two bi-radionuclide plaque models investigated in the present study are designated as Design I and Design II. In Design I, 125I seeds are placed on the top of the plaque, while in Design II 106Ru/106Rh source is positioned on the top of the plaque. In Monte Carlo calculations, the plaque is positioned in a spherical water phantom of 30 cm diameter. RESULTS The proposed bi-radionuclide eye plaque demonstrated superior dose distributions as compared to 125I or 106Ru plaque for tumor thicknesses ranges from 5 to 10 mm. Amongst the designs, dose at a given voxel for Design I is higher as compared to the corresponding voxel dose for Design II. This difference is attributed to the higher degree of attenuation of 125I photons in Ag as compared to beta particles. Influence of different 125I seed models on the normalized lateral dose profiles of Design I (in the absence of carrier) is negligible and within 5% on the central axis depth dose distribution as compared to the corresponding values of the plaque that has indigenous 125I seeds. In the presence of a silastic/acrylic seed carrier, the normalized central axis dose distributions of Design I are smaller by 3%-12% as compared to the corresponding values in the absence of a seed carrier. For the published bi-radionuclide plaque model, good agreement is observed between the Monte Carlo-calculated and published measured depth dose distributions for clinically relevant depths. CONCLUSION Regardless of the type of 125I seed model utilized and whether silastic/acrylic seed carrier is present or not, Design I bi-radionuclide plaque offers superior dose distributions in terms of tumor dose uniformity, rapid dose fall off and lesser dose to nearby critical organs at risk over the Design II plaque. This shows that Design I bi-radionuclide plaque could be a promising alternative to 125I plaque for treatment of tumor sizes in the range 5 to 10 mm.
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Affiliation(s)
- Subhalaxmi Mishra
- Radiological Physics and Advisory Division, Health, Safety & Environment Group, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - T Palani Selvam
- Radiological Physics and Advisory Division, Health, Safety & Environment Group, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, Maharashtra, India
| | - Sridhar Sahoo
- Radiological Physics and Advisory Division, Health, Safety & Environment Group, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - Sanjay Kumar Saxena
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - Yogendra Kumar
- Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - Balvinder K Sapra
- Radiological Physics and Advisory Division, Health, Safety & Environment Group, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai, Maharashtra, India
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Wang H, Zhang R, Wang Y, Chen R, Liu Y, Li Y, Wei W. Retrospective analysis of secondary enucleation for uveal melanoma after plaque radiotherapy. BMC Ophthalmol 2022; 22:163. [PMID: 35397506 PMCID: PMC8994292 DOI: 10.1186/s12886-022-02387-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 04/04/2022] [Indexed: 11/25/2022] Open
Abstract
Background Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. Plaque brachytherapy (PRT) is widely accepted as an effective globe-conserving treatment modality for UM. However, local treatment failure and complications lead to the enucleation of irradiated eyes. We conducted this study to explore the causes and long-term prognosis for UM patients who accepted secondary enucleation after plaque radiotherapy. Methods This was a retrospective cohort study. Data of patients who underwent secondary enucleation for UM after plaque radiotherapy, from July 2007 to July 2019, at Beijing Tongren Hospital were analyzed. Kaplan–Meier analysis was performed to assess the probability of indications, metastasis, and metastasis-related death. Cox regression analysis was used to analyze associations of the prognostic factors. Results Eight hundred and eighty patients were clinically diagnosed with uveal melanoma and initially treated by iodine-125 plaque radiotherapy, 132 of whom underwent secondary enucleation and pathological examination in the same hospital. Fifty-two (39.4%) eyes were enucleated simply because of uncontrollable neovascular glaucoma (NVG). Forty-four (33.3%) patients suffered from tumor recurrence. Tumor non-response occurred in 18 (13.6%) cases. Ten (7.6%) eyes received enucleation entirely due to other types of glaucoma. Failure to preserve the eyes for other reasons occurred in eight (6.1%) patients. At a median follow-up of 58.1 [IQR: 40.9–90.5] months, the systemic spread was detected in 45 (34.1%) patients, and 38 of them died. On multivariate analysis, tumor largest basal diameter (HR 1.15 [95% CI: 1.01, 1.31]), tumor non-response (HR 7.22 [95% CI: 2.63, 19.82]), and recurrence (HR 3.29 [95% CI: 1.54, 7.07]) were risk factors for metastasis. Increased age (HR 1.54 [95% CI: 1.07, 2.23]), tumor non-response (HR 7.91 [95% CI: 2.79, 22.48]), and recurrence (HR 3.08 [95% CI: 1.13, 7.23]) were risk factors for metastasis-related death. Conclusions NVG was the major reason for secondary enucleation for Chinese UM patients after PRT. Tumor non-response and recurrence were associated with a significantly higher risk of long-term metastasis and metastasis-related death.
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Berkowitz ST, Brock AL, Astrahan MA, Reichstein DA. Annulus-shaped I-125 plaque brachytherapy for conjunctival melanoma. Am J Ophthalmol Case Rep 2022; 26:101512. [PMID: 35496762 PMCID: PMC9046954 DOI: 10.1016/j.ajoc.2022.101512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 03/09/2022] [Accepted: 04/03/2022] [Indexed: 11/26/2022] Open
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Sharifzadeh M, Chiniforoush TA, Sadeghi M. Design and optimizing a novel ocular plaque brachytherapy with dual-core of 103Pd and 106Ru. Phys Med 2021; 91:99-104. [PMID: 34742099 DOI: 10.1016/j.ejmp.2021.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/24/2021] [Accepted: 10/05/2021] [Indexed: 10/19/2022] Open
Abstract
In recent decades, eye plaques of brachytherapy have been extensively used as primary treatment as well as a complementary treatment for ocular cancer. The purpose of this study is the development of the eye plaque brachytherapy throughout a new design of eye plaque by combining the COMS plaque and the CCB BEBIG plaque loaded by IRA1-103Pd and 106Ru, respectively. A new dual-core plaque with a diameter of 20 mm was designed in the way that the BEBIG plaque with a diameter of 20 mm loaded by 106Ru plate is attached to the COMS plaque with a diameter of 20 mm loaded by 24 of IRA1-103Pd seeds. Dose calculations for the new plaque were performed by using the MCNP5 code. Dose calculations of dual-core plaque including 103Pd seeds (gamma) and 106Ru plate (beta) were separately done for the sake of MCNP constraints in gamma and beta particle transfer simultaneously. The new dual-core plaque delivers a much higher dose rate to the tumor compared with every single plaque, while the dose rate reached to healthy tissues is slightly higher than each plaque separately. Of course, this is acceptable because the treatment time reduces and subsequently the error in radiation therapy reduces.
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Affiliation(s)
- Mohsen Sharifzadeh
- Radiation Application Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran
| | - Tayebeh A Chiniforoush
- Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Mahdi Sadeghi
- Medical Physics Department, School of Medicine, Iran University of Medical Sciences, P.O. Box: 14155-6183 Tehran, Iran.
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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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Morrison H, Menon G, Larocque MP, van Veelen B, Niatsetski Y, Weis E, Sloboda RS. Initial evaluation of Advanced Collapsed cone Engine dose calculations in water medium for I-125 seeds and COMS eye plaques. Med Phys 2018; 45:1276-1286. [PMID: 29383721 DOI: 10.1002/mp.12776] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/15/2017] [Accepted: 01/11/2018] [Indexed: 12/31/2022] Open
Abstract
PURPOSE To investigate the dose calculation accuracy in water medium of the Advanced Collapsed cone Engine (ACE) for three sizes of COMS eye plaques loaded with low-energy I-125 seeds. METHODS A model of the Oncura 6711 I-125 seed was created for use with ACE in Oncentra® Brachy (OcB) using primary-scatter separated (PSS) point dose kernel and Task Group (TG) 43 datasets. COMS eye plaque models of diameters 12, 16, and 20 mm were introduced into the OcB applicator library based on 3D CAD drawings of the plaques and Silastic inserts. To perform TG-186 level 1 commissioning, treatment plans were created in OcB for a single source in water and for each COMS plaque in water for two scenarios: with only one centrally loaded seed, or with all seed positions loaded. ACE dose calculations were performed in high accuracy mode with a 0.5 × 0.5 × 0.5 mm3 calculation grid. The resulting dose data were evaluated against Monte Carlo (MC) calculated doses obtained with MCNP6, using both local and global percent differences. RESULTS ACE doses around the source for the single seed in water agreed with MC doses on average within < 5% inside a 6 × 6 × 6 cm3 region, and within < 1.5% inside a 2 × 2 × 2 cm3 region. The PSS data were generated at a higher resolution within 2 cm from the source, resulting in this improved agreement closer to the source due to fewer approximations in the ACE dose calculation. Average differences in both investigated plaque loading patterns in front of the plaques and on the plaque central axes were ≤ 2.5%, though larger differences (up to 12%) were found near the plaque lip. CONCLUSIONS Overall, good agreement was found between ACE and MC dose calculations for a single I-125 seed and in front of the COMS plaques in water. More complex scenarios need to be investigated to determine how well ACE handles heterogeneous patient materials.
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Affiliation(s)
- Hali Morrison
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.,Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Geetha Menon
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.,Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | - Matthew P Larocque
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.,Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
| | | | | | - Ezekiel Weis
- Department of Ophthalmology, University of Alberta, Edmonton, Alberta, Canada.,Department of Surgery, University of Calgary, Calgary, Alberta, Canada
| | - Ron S Sloboda
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada.,Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
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Lesperance M, Martinov M, Thomson RM. Monte Carlo dosimetry for 103Pd, 125I, and 131Cs ocular brachytherapy with various plaque models using an eye phantom. Med Phys 2014; 41:031706. [PMID: 24593710 DOI: 10.1118/1.4864474] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To investigate dosimetry for ocular brachytherapy for a range of eye plaque models containing(103)Pd, (125)I, or (131)Cs seeds with model-based dose calculations. METHODS Five representative plaque models are developed based on a literature review and are compared to the standardized COMS plaque, including plaques consisting of a stainless steel backing and acrylic insert, and gold alloy backings with: short collimating lips and acrylic insert, no lips and silicone polymer insert, no lips and a thin acrylic layer, and individual collimating slots for each seed within the backing and no insert. Monte Carlo simulations are performed using the EGSnrc user-code BrachyDose for single and multiple seed configurations for the plaques in water and within an eye model (including nonwater media). Simulations under TG-43 assumptions are also performed, i.e., with the same seed configurations in water, neglecting interseed and plaque effects. Maximum and average doses to ocular structures as well as isodose contours are compared for simulations of each radionuclide within the plaque models. RESULTS The presence of the plaque affects the dose distribution substantially along the plaque axis for both single seed and multiseed simulations of each plaque design in water. Of all the plaque models, the COMS plaque generally has the largest effect on the dose distribution in water along the plaque axis. Differences between doses for single and multiple seed configurations vary between plaque models and radionuclides. Collimation is most substantial for the plaque with individual collimating slots. For plaques in the full eye model, average dose in the tumor region differs from those for the TG-43 simulations by up to 10% for(125)I and (131)Cs, and up to 17% for (103)Pd, and in the lens region by up to 29% for (125)I, 34% for (103)Pd, and 28% for (131)Cs. For the same prescription dose to the tumor apex, the lowest doses to critical ocular structures are generally delivered with plaques containing (103)Pd seeds. CONCLUSIONS The combined effects of ocular and plaque media on dose are significant and vary with plaque model and radionuclide, suggesting the importance of model-based dose calculations employing accurate ocular and plaque media and geometries for eye plaque brachytherapy.
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Affiliation(s)
- Marielle Lesperance
- Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | - M Martinov
- Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | - R M Thomson
- Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6, Canada
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Finger PT, Zhou D, Kalach N, Semenova E, Choi W. 103Pd versus 125I ophthalmic plaque brachytherapy: preoperative comparative radiation dosimetry for 319 uveal melanomas. ACTA ACUST UNITED AC 2014; 3:409-416. [PMID: 25431638 PMCID: PMC4241234 DOI: 10.1007/s13566-014-0149-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 03/24/2014] [Indexed: 11/27/2022]
Abstract
Objective This study was conducted to compare the relative, clinical intraocular dose distribution for palladium-103 (103Pd) versus iodine-125 (125I) ophthalmic plaque radiation therapy. Methods Preoperative comparative radiation dosimetry was performed to evaluate 319 consecutive uveal melanomas treated between 2006 and 2012. Results There were 68 (21.3 %) anterior (iris and/or ciliary body) and 251 (78.7 %) choroidal melanomas examined in this study. According to AJCC staging, 7th edition, 146 (45.8 %) were T1, 126 (39.5 %) T2, 40 (12.5 %) T3, and 7 (2.2 %) T4. All were prescribed an equivalent tumor-apex dose. When compared to 125I, 103Pd was associated with a mean 41.9 % lower radiation dose to the opposite eye wall (p < 0.001), 12.7 % to the lens center (p < 0.001), 7.5 % to the optic disc (p = 0.008), and a 3.8 % decrease to the fovea (p = 0.034). However, subgroup analysis of smaller (T1-staged) tumors showed greater dose reductions to normal ocular structures compared to larger (T4-staged) tumors. Tumor and therefore plaque location also affected intraocular dose distribution. For example, palladium-103-related dose reductions to the fovea, optic nerve, and opposite eye wall were significantly greater for iris and ciliary body tumors compared to posterior choroidal melanomas (p < 0.001). After comparative dosimetry, 98.7 % (n = 315/319) were treated with 103Pd. Conclusion Preoperative comparative radiation dosimetry was performed for a large cohort of patients with uveal melanoma. It influenced radionuclide selection, offered an opportunity for radiation sparing of critical vision-related intraocular structures, and typically increased radiation within the tumors.
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Affiliation(s)
- Paul T. Finger
- The New York Eye Cancer Center, 115 East 61st Street, New York City, NY 10065 USA
- Mt. Sinai Beth Israel Cancer Center, New York City, NY USA
- The New York Eye and Ear Infirmary of Mt. Sinai, New York City, NY USA
- New York University School of Medicine, New York City, NY USA
| | - Di Zhou
- The New York Eye Cancer Center, 115 East 61st Street, New York City, NY 10065 USA
- New York University School of Medicine, New York City, NY USA
| | - Nina Kalach
- Mt. Sinai Beth Israel Cancer Center, New York City, NY USA
| | - Ekaterina Semenova
- The New York Eye Cancer Center, 115 East 61st Street, New York City, NY 10065 USA
- The New York Eye and Ear Infirmary of Mt. Sinai, New York City, NY USA
| | - Walter Choi
- Mt. Sinai Beth Israel Cancer Center, New York City, NY USA
- The New York Eye and Ear Infirmary of Mt. Sinai, New York City, NY USA
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The retina dose-area histogram: a metric for quantitatively comparing rival eye plaque treatment options. J Contemp Brachytherapy 2013; 5:23-32. [PMID: 23634152 PMCID: PMC3635050 DOI: 10.5114/jcb.2013.34450] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 03/11/2013] [Accepted: 03/20/2013] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Episcleral plaques have a history of over a half century in the delivery of radiation therapy to intraocular tumors such as choroidal melanoma. Although the tumor control rate is high, vision-impairing complications subsequent to treatment remain an issue. Notable, late complications are radiation retinopathy and maculopathy. The obvious way to reduce the risk of radiation damage to the retina is to conform the prescribed isodose surface to the tumor base and to reduce the dose delivered to the surrounding healthy retina, especially the macula. Using a fusion of fundus photography, ultrasound and CT images, tumor size, shape and location within the eye can be accurately simulated as part of the radiation planning process. In this work an adaptation of the dose-volume histogram (DVH), the retina dose-area histogram (RDAH) is introduced as a metric to help compare rival plaque designs and conformal treatment planning options with the goal of reducing radiation retinopathy. MATERIAL AND METHODS The RDAH is calculated by transforming a digitized fundus-photo collage of the tumor into a rasterized polar map of the retinal surface known as a retinal diagram (RD). The perimeter of the tumor base is digitized on the RD and its area computed. Area and radiation dose are calculated for every pixel in the RD. RESULTS The areal resolution of the RDAH is a function of the pixel resolution of the raster image used to display the RD and the number of polygon edges used to digitize the perimeter of the tumor base. A practical demonstration is presented. CONCLUSIONS The RDAH provides a quantitative metric by which episcleral plaque treatment plan options may be evaluated and compared in order to confirm adequate dosimetric coverage of the tumor and margin, and to help minimize dose to the macula and retina.
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Chiu-Tsao ST, Astrahan MA, Finger PT, Followill DS, Meigooni AS, Melhus CS, Mourtada F, Napolitano ME, Nath R, Rivard MJ, Rogers DWO, Thomson RM. Dosimetry of (125)I and (103)Pd COMS eye plaques for intraocular tumors: report of Task Group 129 by the AAPM and ABS. Med Phys 2012; 39:6161-84. [PMID: 23039655 DOI: 10.1118/1.4749933] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Dosimetry of eye plaques for ocular tumors presents unique challenges in brachytherapy. The challenges in accurate dosimetry are in part related to the steep dose gradient in the tumor and critical structures that are within millimeters of radioactive sources. In most clinical applications, calculations of dose distributions around eye plaques assume a homogenous water medium and full scatter conditions. Recent Monte Carlo (MC)-based eye-plaque dosimetry simulations have demonstrated that the perturbation effects of heterogeneous materials in eye plaques, including the gold-alloy backing and Silastic insert, can be calculated with reasonable accuracy. Even additional levels of complexity introduced through the use of gold foil "seed-guides" and custom-designed plaques can be calculated accurately using modern MC techniques. Simulations accounting for the aforementioned complexities indicate dose discrepancies exceeding a factor of ten to selected critical structures compared to conventional dose calculations. Task Group 129 was formed to review the literature; re-examine the current dosimetry calculation formalism; and make recommendations for eye-plaque dosimetry, including evaluation of brachytherapy source dosimetry parameters and heterogeneity correction factors. A literature review identified modern assessments of dose calculations for Collaborative Ocular Melanoma Study (COMS) design plaques, including MC analyses and an intercomparison of treatment planning systems (TPS) detailing differences between homogeneous and heterogeneous plaque calculations using the American Association of Physicists in Medicine (AAPM) TG-43U1 brachytherapy dosimetry formalism and MC techniques. This review identified that a commonly used prescription dose of 85 Gy at 5 mm depth in homogeneous medium delivers about 75 Gy and 69 Gy at the same 5 mm depth for specific (125)I and (103)Pd sources, respectively, when accounting for COMS plaque heterogeneities. Thus, the adoption of heterogeneous dose calculation methods in clinical practice would result in dose differences >10% and warrant a careful evaluation of the corresponding changes in prescription doses. Doses to normal ocular structures vary with choice of radionuclide, plaque location, and prescription depth, such that further dosimetric evaluations of the adoption of MC-based dosimetry methods are needed. The AAPM and American Brachytherapy Society (ABS) recommend that clinical medical physicists should make concurrent estimates of heterogeneity-corrected delivered dose using the information in this report's tables to prepare for brachytherapy TPS that can account for material heterogeneities and for a transition to heterogeneity-corrected prescriptive goals. It is recommended that brachytherapy TPS vendors include material heterogeneity corrections in their systems and take steps to integrate planned plaque localization and image guidance. In the interim, before the availability of commercial MC-based brachytherapy TPS, it is recommended that clinical medical physicists use the line-source approximation in homogeneous water medium and the 2D AAPM TG-43U1 dosimetry formalism and brachytherapy source dosimetry parameter datasets for treatment planning calculations. Furthermore, this report includes quality management program recommendations for eye-plaque brachytherapy.
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Zhang H, Davidorf F, Qi Y. Comparison of 16 mm OSU-Nag and COMS eye plaques. J Appl Clin Med Phys 2012; 13:3632. [PMID: 22584165 PMCID: PMC5716566 DOI: 10.1120/jacmp.v13i3.3632] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 01/05/2012] [Accepted: 01/06/2012] [Indexed: 11/23/2022] Open
Abstract
OSU-NAG eye plaques use fewer sources than COMS-plaques of comparable size, and do not employ a Silastic seed carrier insert. Monte Carlo modeling was used to calculate 3D dose distributions for a 16 mm OSU-NAG eye plaque and a 16 mm COMS eye plaque loaded with either Iodine-125 or Cesium-131 brachytherapy sources. The OSU-NAG eye plaque was loaded with eight sources forming two squares, whereas the COMS eye plaque was loaded with thirteen sources approximating three isocentric circles. A spherical eyeball 24.6 mm in diameter and an ellipsoid-like tumor 6 mm in height and 12 mm in the major and minor axes were used to evaluate the doses delivered. To establish a fair comparison, a water seed carrier was used instead of the Silastic seed carrier designed for the traditional COMS eye plaque. Calculations were performed on the dose distributions along the eye plaque axis and the DVHs of the tumor, as well as the 3D distribution. Our results indicated that, to achieve a prescription dose of 85 Gy at 6 mm from the inner sclera edge for a six-day treatment, the OSU-NAG eye plaque will need 6.16 U/source and 6.82U/source for 125I and 131Cs, respectively. The COMS eye plaque will require 4.02 U/source and 4.43 U/source for the same source types. The dose profiles of the two types of eye plaques on their central axes are within 9% difference for all applicable distances. The OSU-NAG plaque delivers about 10% and 12% more dose than the COMS for 125I and 131Cs sources, respectively, at the inner sclera edge, but 6% and 3% less dose at the opposite retina. The DVHs of the tumor for two types of plaques were within 6% difference. In conclusion, the dosimetric quality of the OSU-NAG eye plaque used in eye plaque brachytherapy is comparable to the COMS eye plaque.
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Affiliation(s)
- Hualin Zhang
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Gagne NL, Leonard KL, Huber KE, Mignano JE, Duker JS, Laver NV, Rivard MJ. BEDVH-A method for evaluating biologically effective dose volume histograms: Application to eye plaque brachytherapy implants. Med Phys 2012; 39:976-83. [DOI: 10.1118/1.3679010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Melhus CS. Improved Eye Plaque Brachytherapy Dosimetry Using Monte Carlo Methods. NUCL TECHNOL 2011. [DOI: 10.13182/nt11-a12266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Christopher S. Melhus
- Tufts Medical Center, Tufts Medical Center, Box 246 800 Washington Street, Boston, Massachusetts 02111
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Finger PT, Chin KJ, Yu GP, Patel NS. Risk Factors for Cataract After Palladium-103 Ophthalmic Plaque Radiation Therapy. Int J Radiat Oncol Biol Phys 2011; 80:800-6. [DOI: 10.1016/j.ijrobp.2010.02.051] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 02/18/2010] [Indexed: 11/17/2022]
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Finger PT, Chin KJ, Yu GP. Risk factors for radiation maculopathy after ophthalmic plaque radiation for choroidal melanoma. Am J Ophthalmol 2010; 149:608-15. [PMID: 20138602 DOI: 10.1016/j.ajo.2009.11.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 10/26/2009] [Accepted: 11/01/2009] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine how tumor characteristics and radiation dose affect the incidence of radiation maculopathy (RM). DESIGN Retrospective, consecutive case series. METHODS A consecutive case series of 384 uveal melanomas irradiated (mean apical dose, 71.2 Gy) were followed up for a mean 47.2 months. Tumor locations included: 122 (32%) centered anterior to the equator, 27 (7%) equatorial, and 235 (61%) posterior. Tumor sizes were American Joint Committee on Cancer class T1 (n = 180), T2 (n = 150), T3 (n = 47), and T4 (n = 7). RESULTS RM occurred in 8 (7%) eyes with anterior uveal melanomas. In contrast, it was found in 82 (41%) eyes with posterior tumors. Multivariate analysis revealed the risk related to posterior location was greater compared with anterior location with a hazard ratio of 6.66 (95% confidence interval [CI], 4.94 to 22.50; P = .0001). Tumor height (> 6.0 mm) also demonstrated a high risk for RM (hazard ratio, 4.5; 95% CI, 2.68 to 10.17; P = .0001). A significant dose-response relationship was found between dose to fovea and RM (P = .0005, for trend). As compared with a dose of < 35 Gy, the risk of RM was 1.74 (95% CI, 0.98 to 3.1) for doses from 35 to 70 Gy, and the risk of RM was 2.43 (95% CI, 1.48 to 4.0) for doses of 70 Gy or more. Of interest, those anterior melanomas with RM had a mean apical height of 9.4 mm, as compared with a mean height of 3.3 mm for anterior tumors not associated with RM. Visual acuity was preserved if the fovea dose was less than 35 Gy. CONCLUSIONS This study suggests that tumor location, tumor thickness, and radiation dose to the fovea are risk factors for the development of RM.
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Affiliation(s)
- Paul T Finger
- The New York Eye Cancer Center, New York, New York; The New York Eye and Ear Infirmary, New York, NY 10065, USA. pfinger@eyecancer
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Zhang H, Martin D, Chiu-Tsao ST, Meigooni A, Thomadsen BR. A comprehensive dosimetric comparison between (131)Cs and (125)I brachytherapy sources for COMS eye plaque implant. Brachytherapy 2010; 9:362-72. [PMID: 20116342 DOI: 10.1016/j.brachy.2009.07.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 06/23/2009] [Accepted: 07/28/2009] [Indexed: 10/19/2022]
Abstract
PURPOSE To verify the dosimetric characteristics of (131)Cs source in the Collaborative Ocular Melanoma Study (COMS) eye plaque brachytherapy, to compare (131)Cs with (125)I in a sample implant, and to examine the accuracy of treatment planning system in dose calculation. METHODS AND MATERIALS Monte Carlo (MC) technique was used to generate three-dimensional dose distributions of a 16-mm COMS eye plaque loaded with (131)Cs and (125)I brachytherapy sources separately. A spherical eyeball, 24.6mm in diameter, and an ellipsoidal tumor, 6mm in height and 12mm in diameter, were used to evaluate the doses delivered. The simulations were carried out both with and without the gold and gold alloy plaque. A water-equivalent seed carrier was used instead of the silastic insert designed for the traditional COMS eye plaque. The 13 sources involved were also individually simulated to evaluate the intersource effect. In addition, a treatment planning system was used to calculate the doses at the central axis for comparison with MC data. RESULTS The gold plaque had significantly reduced the dose in the tumor volume; at the prescription point of this study, that is, 6mm from the edge of inner sclera, the gold plaque reduced the dose by about 7% for both types of (131)Cs and (125)I sources, but the gold alloy plaque reduced the dose only by 4% for both types of sources. The intersource effect reduced the dose by 2% for both types of sources. At the same prescription dose, the treatment with the gold plaque applicator tended to create more hot regions for either type of sources than were seen with the homogeneous water phantom. The doses of TPS agree with the MC. CONCLUSION The (131)Cs source is comparable to the (125)I source in the eye plaque brachytherapy. The TPS can provide accurate dose calculations for eye plaque implants with either type of sources.
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Affiliation(s)
- Hualin Zhang
- Department of Radiation Oncology, The Ohio State University, Columbus, OH 43210-1228, USA.
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Finger PT, Chin KJ, Duvall G. Palladium-103 ophthalmic plaque radiation therapy for choroidal melanoma: 400 treated patients. Ophthalmology 2009; 116:790-6, 796.e1. [PMID: 19243829 DOI: 10.1016/j.ophtha.2008.12.027] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 11/21/2008] [Accepted: 12/05/2008] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To describe 18 years of experience with palladium-103 ((103)Pd) ophthalmic plaque brachytherapy. DESIGN Retrospective case series. PARTICIPANTS From 1990 to 2007, 400 patients were diagnosed with uveal melanoma, found negative for metastatic disease, and treated. Episcleral (103)Pd radiation was delivered to a mean apical radiation dose of 73.3 Gy over 5 to 7 continuous days. INTERVENTION Palladium-103 ophthalmic plaque brachytherapy. MAIN OUTCOME MEASURES Patients were evaluated for local tumor control, visual acuity, radiation damage (retinopathy, optic neuropathy, cataract), and metastatic disease. RESULTS A total of 272 tumors (68%) were located at or posterior to the equator. There were 186 (46.5%) T1 tumors, 156 (39%) T2 tumors, 50 (12.5%) T3 tumors, and 8 (2%) T4 tumors. Patients were followed for a maximum of 205 months (mean, 51.1 months). Fourteen patients required secondary enucleation (5 for tumor growth and 9 for glaucoma pain control). The local control rate was 96.7%. Life table analysis of patients with 20/200 or better before treatment (n = 357) suggests that 79% and 69% are expected to retain that acuity for 5 and 10 years, respectively. Life table analysis demonstrates a probability that 92.7% and 86.6% of patients will be free of metastatic disease at 5 and 10 years, respectively. CONCLUSIONS In a nonrandomized phase I clinical evaluation, (103)Pd ophthalmic plaque radiotherapy was used to treat 400 patients with uveal melanoma. In this series, results after (103)Pd ophthalmic plaque radiotherapy were superior to those reported for alternative forms of radiation.
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Affiliation(s)
- Paul T Finger
- The New York Eye Cancer Center, New York, New York 10065, USA.
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Mourão AP, Campos TPRD. Considerações radiodosimétricas da braquiterapia ocular com iodo-125 e rutênio/ródio-106. Radiol Bras 2009. [DOI: 10.1590/s0100-39842009000100010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
OBJETIVO: Analisar, por meio de um modelo computacional da região ocular, as características da distribuição da dose utilizando placas contendo iodo-125 e rutênio/ródio-106. MATERIAIS E MÉTODOS: Foi utilizado um modelo computacional de voxels da região ocular incluindo os diversos tecidos, com a placa posicionada sobre a esclera. O código Monte Carlo foi utilizado para simular a irradiação. A distribuição da dose é apresentada por curvas de isodoses. RESULTADOS: As simulações computacionais apresentam a distribuição da dose no interior do bulbo e nas estruturas externas. Os resultados permitem comparar a distribuição espacial das doses geradas por partículas beta e por fótons. As simulações mostram que a aplicação de sementes de iodo-125 implica alta dose no cristalino, enquanto o rutênio/ródio-106 produz alta dose na superfície da esclera. CONCLUSÃO: A dose no cristalino depende da espessura do tumor, da posição e do diâmetro da placa, e do radionuclídeo utilizado. No presente estudo, a fonte de rutênio/ródio-106 é recomendada para tumores de dimensões reduzidas. A irradiação com iodo-125 gera doses maiores no cristalino do que a irradiação com rutênio/ródio-106. O valor máximo de dose no cristalino corresponde a 12,75% do valor máximo de dose com iodo-125 e apenas 0,005% para rutênio/ródio-106.
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Rivard MJ, Melhus CS, Sioshansi S, Morr J. The impact of prescription depth, dose rate, plaque size, and source loading on the central axis using 103Pd, 125I, and 131Cs. Brachytherapy 2008; 7:327-35. [DOI: 10.1016/j.brachy.2008.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Revised: 04/06/2008] [Accepted: 05/28/2008] [Indexed: 12/28/2022]
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Melhus CS, Rivard MJ. COMS eye plaque brachytherapy dosimetry simulations for P103d, I125, and C131s. Med Phys 2008; 35:3364-3371. [DOI: 10.1118/1.2940604] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 05/20/2008] [Accepted: 05/20/2008] [Indexed: 11/07/2022] Open
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Finger PT. Finger's "slotted" eye plaque for radiation therapy: treatment of juxtapapillary and circumpapillary intraocular tumours. Br J Ophthalmol 2007; 91:891-4. [PMID: 17327263 PMCID: PMC1955638 DOI: 10.1136/bjo.2007.114082] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To create "slotted eye plaques" for the treatment of juxtapapillary and circumpapillary intraocular tumours. METHODS Eye plaques were altered such that 8 mm-wide slots (variable length) were created to accommodate the orbital portion of the optic nerve. Thus, as the nerve entered the slot, the plaque's posterior margin extended beyond the optic disc. Radioactive seeds were affixed around the slot, surrounding the juxtapapillary and posterior tumour margins. RESULTS As proof of principle, three patients with choroidal melanomas that encircled or were in contact with the optic disc (considered untreatable with a notched eye plaque) were considered to be initial candidates for slotted-plaque radiotherapy. Preoperative three-dimensional C-scan imaging of their optic nerve sheath diameters insured that they would fit in the slotted plaque. Intraoperative ultrasound imaging was used to confirm proper plaque placement. Radiation dosimetry modelling showed that all tumour tissue received a minimum of 85 Gy (despite the gap created by the slot). With relatively short-term follow-up, there has been no evidence of ocular ischaemia, tumour growth or complications attributable to the use of slotted-plaque radiation therapy. CONCLUSION Slotted plaques accommodate the retrobulbar optic nerve into the device and thereby shift the treatment zone to improve coverage of both juxtapapillary and circumpapillary intraocular tumours.
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Affiliation(s)
- Paul T Finger
- The New York Eye Cancer Centre, 115 East 61st Street, New York City, NY 10065, USA.
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