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De Brabandere M, Placidi E, Siebert FA, Carlsson Tedgren Å, Slocker Escarpa A, Tagliaferri L, Andrássy M, Schulz C, Fog LS. GEC-ESTRO survey of 106Ru eye applicator practice for ocular melanoma - Physicist survey. Radiother Oncol 2024; 193:110114. [PMID: 38309583 DOI: 10.1016/j.radonc.2024.110114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/16/2024] [Accepted: 01/27/2024] [Indexed: 02/05/2024]
Abstract
AIM 106Ru eye plaque brachytherapy (BT, interventional radiotherapy) is an eye-preserving treatment for uveal melanoma performed in about 100 clinics worldwide. Despite this relatively low number, there is a considerable variation in clinical practice. In 2022, the BRAPHYQS and Head & Neck and Skin GEC-ESTRO working groups conducted a survey to map the current clinical practice. The survey consisted of a physicist and a physician part. This paper describes the physicist results. However, three physician questions with overlapping interest are included here as well. MATERIALS AND METHODS The survey questions pertained to commissioning and quality control (QC) of the plaques, treatment planning, radiobiological correction, as well as more general questions on practice improvement. The questions overlapping with the physician survey were related to dose prescription and margins. RESULTS Sixty-five physicist responses were included. A majority of the centres do not perform an independent measurement of the absorbed dose at reference depth, percentage depth dose (PDD) and off-axis data. A lack of calibration services and suitable equipment are the main reasons. About one third of the centres indicated that they do image based treatment planning. The use of margins and dose prescription showed a large variability, despite the availability of guidelines [1]. Many respondents expressed a strong wish for improvement in a wide range of aspects of clinical practice. CONCLUSION The physics survey showed a wide variability regarding quality control of the 106Ru sources and treatment planning practice.
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Affiliation(s)
| | - Elisa Placidi
- UOC Physics for Life Sciences, Diagnostic Imaging, Oncologic Radiotherapy and Hematology, Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, Rome, Italy
| | - Frank-André Siebert
- Clinic of Radiotherapy (Radiooncology), University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Åsa Carlsson Tedgren
- Radiation Physics, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden; Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden; Department of Oncology Pathology, Karolinska Institute, Stockholm, Sweden
| | | | - Luca Tagliaferri
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Gemelli ART (Advanced Radiation Therapy), Interventional Oncology Center (IOC), Rome, Italy
| | - Michael Andrássy
- Eckert & Ziegler BEBIG GmbH, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Carmen Schulz
- Eckert & Ziegler BEBIG GmbH, Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Lotte S Fog
- Ocular oncology unit, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Alfred Health Radiation Oncology, Melbourne, VIC, Australia
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Dupere JM, Munro JJ, Medich DC. Intensity modulated high dose rate ocular brachytherapy using Se-75. Brachytherapy 2021; 20:1312-1322. [PMID: 34561174 DOI: 10.1016/j.brachy.2021.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 06/16/2021] [Accepted: 08/02/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE We propose an alternative to LDR brachytherapy for the treatment of ocular melanomas by coupling intensity modulation, through the use of a gold shielded ring applicator, with a middle energy HDR brachytherapy source, Se-75. In this study, we computationally test this proposed design using MCNP6. METHODS AND MATERIALS An array of discrete Se-75 sources is formed into a ring configuration within a gold shielded applicator, which collimates the beam to a conical shape. Varying this angle of collimation allows for the prescription dose to be delivered to the apex of various sized targets. Simulations in MCNP6 were performed to calculate the dosimetric output of the Se-75 ring source for various sized applicators, collimators, and target sizes. RESULTS The prescription dose was delivered to a range of target apex depths 3.5-8 mm in the eye covering targets 10-15 mm in diameter by using various sized applicators and collimators. For a 16 mm applicator with a collimator opening that delivers the prescription dose to a depth of 5 mm in the eye, the maximum percent dose rate to critical structures was 30.5% to the cornea, 35.7% to the posterior lens, 33.3% to the iris, 20.1% to the optic nerve, 278.0% to the sclera, and 267.3% to the tumor. CONCLUSIONS When using Se-75 in combination with the proposed gold shielded ring applicator, dose distributions are appropriate for ocular brachytherapy. The use of a collimator allows for the dose to more easily conform to the tumor volume. This method also reduces treatment time and cost, and it eliminates hand dose to the surgeon through the use of a remote afterloader device.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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] [What about the content of this article? (0)] [Affiliation(s)] [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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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: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Studenski MT, Patel NV, Markoe A, Harbour JW, Samuels SE. Influence of tumor shape and location in eye plaque brachytherapy dosimetry. Brachytherapy 2020; 19:249-254. [PMID: 32061535 DOI: 10.1016/j.brachy.2020.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 12/16/2019] [Accepted: 01/02/2020] [Indexed: 10/25/2022]
Abstract
PURPOSE A common treatment planning technique for eye plaque brachytherapy is to model the tumor as an ellipse. For posterior tumors near the optic disc and fovea, this approach may lead to overlap between tumor and the organ at risk (OAR). We hypothesized that a superior plan can be generated by modeling the actual tumor shape. MATERIALS AND METHODS Forty eye plaque patients with tumors <1 cm from the optic disc and fovea were selected. Two treatment plans were generated for each patient: an elliptical tumor model plan and a true tumor model plan. Dosimetric data were collected for each plan, and Wilcoxon signed-rank tests were used to asses any statistically significant differences. RESULTS Equivalent tumor coverage was confirmed between the elliptical and true tumor plans for all patients. Qualitative analysis showed greater dosimetric differences between plans as the distance from the OARs increased from 0 to 2 mm but the largest differences were observed between 2 and 4 mm. Minimal differences between models were seen beyond 4 mm. Statistically significant dosimetric improvements were found for tumors <4 mm from the fovea and <2 mm from the optic disc. CONCLUSIONS Intuitively, accurate modeling of the tumor accounting for irregularities in the shape should result in a more conformal plan and an overall reduction in OAR dose. However, this technique is only beneficial for tumors that are within 4 mm of the fovea or optic disc. An elliptical tumor model allows for an acceptable plan unless the tumor is located posteriorly and has an irregular shape.
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Affiliation(s)
- Matthew T Studenski
- Department of Radiation Oncology, University of Miami Sylvester Comprehensive Cancer Center, Miami, FL.
| | - Nirav V Patel
- Department of Radiation Oncology, University of Miami Sylvester Comprehensive Cancer Center, Miami, FL
| | - Arnold Markoe
- Department of Radiation Oncology, University of Miami Sylvester Comprehensive Cancer Center, Miami, FL
| | - J William Harbour
- Department of Ophthalmology, University of Miami Bascom Palmer Eye Institute, Miami, FL
| | - Stuart E Samuels
- Department of Radiation Oncology, University of Miami Sylvester Comprehensive Cancer Center, Miami, FL
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Liu W, Kim JM, Young BK, Nath R, Chen Z, Decker RH, Astrahan MA, Pointdujour-Lim R. Novel Eye Plaque Designs for Brachytherapy of Iris and Ciliary Body Melanoma and the First Clinical Application. Ocul Oncol Pathol 2018; 5:220-227. [PMID: 31049331 DOI: 10.1159/000493269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 08/17/2018] [Indexed: 12/20/2022] Open
Abstract
Background While traditional eye plaque brachytherapy can be used for the treatment of iris melanoma, it faces challenges of poor patient tolerability due to cornea-plaque touch caused by radius of curvature mismatch and potential dosimetric inaccuracy from incomplete coverage. We present novel plaque designs and the first clinical application of the plaques for iris melanoma. Methods Two dome-shaped plaques (EP2132 and EP1930) were designed to vault above the cornea to treat tumors of the iris and ciliary body. Image-based treatment planning of the first 2 clinical cases using the EP2132 plaque covered the tumor base plus a 2 mm margin and the involved ciliary body with at least 75 Gy to the tumor apex. Results The tumors decreased in size following treatment. The patients tolerated the treatment well. There was no adverse event associated with the traditional iris plaques, such as decreased vision, pain, corneal edema, glaucoma, or cataract. Conclusion The novel dome-shaped plaques for the treatment of iris melanoma provide effective dose distribution, improved surgical maneuverability, and increased tolerability for the patient. This plaque model can be used to treat iris melanoma of various sizes, configurations, and locations, including the ciliary body. The need for a customized plaque platform for each patient is minimized.
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Affiliation(s)
- Wu Liu
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA.,Yale Smilow Cancer Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jenna May Kim
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Benjamin K Young
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Ravinder Nath
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA.,Yale Smilow Cancer Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Zhe Chen
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA.,Yale Smilow Cancer Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Roy H Decker
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA.,Yale Smilow Cancer Center, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | - Renelle Pointdujour-Lim
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut, USA.,Yale Smilow Cancer Center, Yale University School of Medicine, New Haven, Connecticut, USA
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Stöckel E, Eichmann M, Flühs D, Sommer H, Biewald E, Bornfeld N, Spaan B, Sauerwein W. Dose Distributions and Treatment Margins in Ocular Brachytherapy with 106Ru Eye Plaques. Ocul Oncol Pathol 2017; 4:122-128. [PMID: 30320093 DOI: 10.1159/000479558] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 07/14/2017] [Indexed: 11/19/2022] Open
Abstract
Brachytherapy with 106Ru eye plaques is the most common treatment modality for small to medium-sized uveal melanomas in Europe. So far, no standardized or widely accepted dose prescription protocol for the irradiation of intraocular tumors with 106Ru eye plaques has been defined. For 125I plaques, the minimum dose required for tumor control should be at least 85 Gy. Concerning 106Ru plaques, the dose prescriptions at the University Hospital of Essen foresees minimum doses of 700 Gy to the tumor base and 130 Gy to the tumor apex. These dose prescriptions are expected to ensure sufficient treatment margins. We apply these dose prescriptions to different eye plaque types and tumor sizes and discuss the resulting treatment margins. These investigations are based on Monte Carlo simulations of dose distributions of 3 different eye plaque types. The treatment margin in apical direction has an expansion of at least 0.8 mm for all investigated eye plaques. For symmetrically formed eye plaques, the treatment margin at the base of the tumor goes beyond the visible edge of the plaque. This study focuses on the shape of 85-Gy isodose lines and on treatment margins for different eye plaque types and tumor sizes and shall help exchange knowledge for ocular brachytherapy.
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Affiliation(s)
- Erik Stöckel
- Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany
| | - Marion Eichmann
- Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany
| | - Dirk Flühs
- Strahlenklinik, Universitätsklinikum Essen, Essen, Germany
| | - Holger Sommer
- Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany
| | - Eva Biewald
- Zentrum für Augenheilkunde, Universitätsklinikum Essen, Essen, Germany
| | - Norbert Bornfeld
- Zentrum für Augenheilkunde, Universitätsklinikum Essen, Essen, Germany
| | - Bernhard Spaan
- Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Johnson JE, Deufel CL, Furutani KM. Investigating the dosimetric impact of seed location uncertainties in Collaborative Ocular Melanoma Study-based eye plaques. Brachytherapy 2016; 15:661-8. [PMID: 27475484 DOI: 10.1016/j.brachy.2016.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 06/01/2016] [Accepted: 06/05/2016] [Indexed: 02/08/2023]
Abstract
PURPOSE To quantify the dosimetric effects of random and systematic seed position uncertainties in Collaborative Ocular Melanoma Study-based eye plaques. METHODS AND MATERIALS An eye plaque dose calculation routine was created using Task Group 43 formalism. A variety of clinical configurations were simulated, including two seed models: (125)I and (103)Pd, three eye plaque sizes, and eight plaque/eye orientations. Dose was calculated at four ocular anatomic sites and three central axis plaque depths. Random seed positional uncertainty was modeled by adding Gaussian random displacements, in one of three seed-motion degrees of freedom, to each seed's nominal coordinate. Distributions of dosimetric outcomes were obtained and fitted after 10(6) randomizations. Similar analysis was performed for deterministic, systematic shifts of the plaque along the eye surface and radially from the globe center. RESULTS Random seed placement uncertainties of 0.2-mm root mean square (RMS) (amplitude) produce dose changes that are typically <4% for each degree of freedom (95% confidence interval). Systematic seed placement uncertainties are generally greater than random uncertainty 95% confidence intervals (factor of 0.72-2.15), with the relative magnitudes depending on plaque size and location of interest. Eye plaque dosimetry is most sensitive to seed movement toward the center of the eye. Dosimetric uncertainty also increases with increasing dose gradients, which are typically greatest near the inner sclera, with smaller plaques, and with lower energy radionuclides (e.g., (103)Pd). CONCLUSIONS Dosimetric uncertainties due to the random seed positional displacements anticipated in the clinic are expected to be <4% for each degree of freedom in most circumstances.
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11
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Karlsson M, Nilsson J, Lundell M, Carlsson Tedgren A. Monte Carlo dosimetry of the eye plaque design used at the St. Erik Eye Hospital for (125)I brachytherapy. Brachytherapy 2014; 13:651-6. [PMID: 24950821 DOI: 10.1016/j.brachy.2014.05.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 05/16/2014] [Accepted: 05/16/2014] [Indexed: 11/25/2022]
Abstract
PURPOSE At St. Erik Eye Hospital in Stockholm, Sweden, ocular tumors of apical height above 6 mm are treated with brachytherapy, using iodine-125 seeds attached to a gold alloy plaque while the treatment planning is performed assuming homogeneous water surroundings. The aim of this work was to investigate the dose-modifying effects of the plaque and the seed fixating silicone rubber glue. METHODS AND MATERIALS The impact of the gold plaque and silicone rubber glue was studied with the Monte Carlo N-particle transport code, version 5. RESULTS For the 2 cm most proximal to the plaque surface along the plaque's central axis, the eyeball received 104.6-93.0% of the dose in all-water conditions. CONCLUSIONS The 0.3 mm thick layer of silicone rubber glue, used for seed fixation, attenuates photons little enough to allow characteristic X-rays from the gold alloy plaque to reach the eyeball. Close to the plaque, the dose rates were higher with the plaque and glue present, than in homogeneous water conditions. This is in contrast to what has been reported for more commonly used eye plaques, demonstrating the importance of investigating the dosimetry of individual treatment systems.
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Affiliation(s)
- Mattias Karlsson
- Division of Radiological Sciences, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden; Department of Medical Physics, Karolinska University Hospital, Stockholm, Sweden.
| | - Josef Nilsson
- Department of Medical Physics, Karolinska University Hospital, Stockholm, Sweden
| | - Marie Lundell
- Department of Medical Physics, Karolinska University Hospital, Stockholm, Sweden; Department of Oncology, Karolinska Institutet, Stockholm, Sweden
| | - Asa Carlsson Tedgren
- Swedish Radiation Safety Authority, Stockholm, Sweden; Department of Medical and Health Sciences and Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
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12
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Barker CA, Francis JH, Cohen GN, Marr BP, Wolden SL, McCormick B, Abramson DH. (106)Ru plaque brachytherapy for uveal melanoma: factors associated with local tumor recurrence. Brachytherapy 2014; 13:584-90. [PMID: 24880583 DOI: 10.1016/j.brachy.2014.04.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 03/27/2014] [Accepted: 04/10/2014] [Indexed: 11/17/2022]
Abstract
PURPOSE Plaque brachytherapy is a common form of treatment for uveal melanoma, and the Collaborative Ocular Melanoma Study (COMS) used (125)I. Recently, (106)Ru has been reintroduced for plaque brachytherapy in the United States. We reviewed our experience treating uveal melanoma with (106)Ru plaque brachytherapy using COMS planning techniques, hypothesizing that we would observe similar outcomes to those in the COMS. METHODS AND MATERIALS Medical records of patients undergoing (106)Ru plaque brachytherapy were reviewed retrospectively. Patient, tumor, and treatment characteristics were recorded. Outcomes including visual acuity, local tumor recurrence, salvage treatment, metastasis, and survival were recorded. Cox regression analyses were used to determine factors associated with local tumor recurrence and enucleation. RESULTS Twenty-eight patients were studied. Median age was 60 years, and 50% were men. Median tumor base diameter and height were 9.4 and 2.6 mm, respectively. Ophthalmic complications were rare. Local tumor recurrence and enucleation occurred in 13 and 4 patients, respectively. Local tumor recurrence was associated with low visual acuity in the tumor-bearing eye, posterior tumors, small plaque size, and difference in plaque-tumor diameter of <6 mm. Enucleation was associated with low visual acuity and posteriorly located tumor. Estimated 5-year rate of death and metastasis was 18.5% and 11.4%, respectively. CONCLUSIONS Among patients treated with (106)Ru plaque brachytherapy using COMS planning techniques, we found a greater than expected rate of local tumor recurrence. Planning (106)Ru plaque brachytherapy should be done carefully at centers that have previously used COMS protocols and (125)I.
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Affiliation(s)
- Christopher A Barker
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY.
| | - Jasmine H Francis
- Ophthalmic Oncology Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Gil'ad N Cohen
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Brian P Marr
- Ophthalmic Oncology Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Suzanne L Wolden
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Beryl McCormick
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY
| | - David H Abramson
- Ophthalmic Oncology Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY
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