Ocular plaque brachytherapy with I-125 and Ru-106: Treatment planning and QA aspects
Marisol De Brabandere,
Belgium
SP-0525
Abstract
Ocular plaque brachytherapy with I-125 and Ru-106: Treatment planning and QA aspects
Authors: Marisol De Brabandere1
1University Hospital Leuven, Dept. of Radiation Oncology, Leuven, Belgium
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Abstract Text
Ocular plaque brachytherapy is a treatment technique for uveal melanoma, offering equivalent tumor control to enucleation while preserving the eye. The most widely used ophthalmic applicators are the COMS type plaques with low energy photon I-125 sources and the beta-emitting Ru-106 plaques, the latter mainly in Europe. For COMS type plaques using I-125 seeds there are well established guidelines ensuring a level of uniformity in the treatment planning and quality management process. For Ru-106 plaque brachytherapy there are no standardized methods for source calibration, applicator commissioning and treatment planning.
In this presentation we focus on Ru-106 plaques. Acceptance and quality control aspects are discussed in more detail: measurements of dose rate, dose uniformity and relative depth dose profiles are challenging due to the limited availability of commercial equipment and calibration services. Also treatment planning strategies for Ru-106 are limited as there is no certified TPS available on the market. Most centers perform a 1D calculation to obtain the treatment time for a given prescribed dose. Dose prescription, treatment time calculation, and dose rate aspects are discussed.