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prithvi Mruthyunjaya, Christina Binder, Amy C Schefler, Michael Seider, Alison Skalet; Real-world plaque brachytherapy clinical practices among Ocular Oncology Study Consortium treatment centers. Invest. Ophthalmol. Vis. Sci. 2018;59(9):3624. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Planning for I-125 plaque brachytherapy (PBT) for uveal melanoma has advanced in recent years, allowing for image-guided planning and improved dosimetry. In order to compare real-world treatment practices, this study reports PBT practice patterns at institutions from the Ocular Oncology Study Consortium (OOSC).
Information regarding brachytherapy clinical practices was obtained from the OOSC database and a treatment practice survey. The OOSC database contains information from 9 U.S. referral centers regarding tumor characteristics and treatment parameters for 428 subjects treated between 2010 and 2014. The survey queried treatment planning methods and prescriptions and was completed by 7 of the OOSC institutions
The majority of institutions follow American Brachytherapy Society (ABS) and American Association of Physicists in Medicine guidelines with regard to dose and prescription point (Table 1). Actual dosimetry methodology varied between institutions with median apical dose of 85Gy and dose rate of 78cGy/hr. Safety margins generally adhered to the 2-3mm guideline but were larger in some cases, particularly for notched plaques or anterior tumors. 85% of institutions used pre-loaded plaques while all institutions now usePlaque Simulator (Eye Physics LLC, Los Angles, CA). Normal tissue constraints are not used at most institutions.
While there were differences in dosimetric practices, there was overall good agreement among PBT practices at the participating institutions including prescription dose, safety margins, and planning methodology. Although it is not FDA-approved, all institutions responding to the survey are now using the Plaque Simulator for treatment planning. However, dose-rates varied between institutions and in some cases fell outside of ABS guidelines. Improved planning technology may allow for more uniform dose calculations to normal structures and improved tumor dosimetry for entry into treatment trials to minimizing radiation toxicity. Further studies are required to refine uncertainties in planning and determine a minimally effective dose.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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