ESTRO 2022

Session Item

Sunday

May 08

14:15 - 15:30

Auditorium 11

Ocular plaque brachytherapy

Chair: Frank-André Siebert, Germany;

Co-Chair: Michele Keane, Ireland

Overview: In three separate presentations, this symposium will address aspects of Ocular Plaque Brachytherapy in current clinical practice. The speakers will discuss a range of topics in relation to I-125 and Ru-106 radioisotopes, from their clinical application in the treatment of ocular carcinomas, to their relative Clinical Quality Assurance and treatment planning requirements. Radiobiological relevance with regard to clinical management and resultant treatment outcomes will also be considered. The recent GEC-ESTRO Survey on Ocular Plaque Brachytherapy, which serves to evaluate clinical practice using Ru-106 plaques, will also be presented and analysed in this symposium.

Session Type: Symposium

Track: Brachytherapy

Journey:

14:15 - 14:40

Ocular plaque brachytherapy with I-125 and Ru-106: Treatment planning and QA aspects

Speaker: Marisol De Brabandere, Belgium

Presentation Number: SP-0525

Abstract

Abstract Title:

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.