ESTRO 2025 - Abstract Book

S4089

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2025

2507

Poster Discussion A low-cost, flexible, and accurate technique to study new immobilisation systems for radiotherapy and their positional reproducibility and stability Chung Tin Lo 1,2 , Tracy Underwood 3,2 , Gary Royle 2 , Jamie McClelland 1,2 1 UCL Hawkes Institute, University College London, London, United Kingdom. 2 Department of Medical Physics and Bioengineering, University College London, London, United Kingdom. 3 Research Department, Leo Cancer Care Ltd, Horley, United Kingdom Purpose/Objective: Recently there has been a resurgence of interest in upright, gantry-less radiotherapy due to its potential to (i) reduce the costs associated with new treatment rooms (particularly for protons/ions) and (ii) improve comfort / clinical outcomes for certain patients groups (1). Consequently, new patient positioning and immobilisation devices are being developed for upright treatments, as well as for conventional supine radiotherapy. Before any new RT immobilisation system is implemented clinically, pre-clinical tests should be performed to verify the reproducibility/stability of that system. Surface-guided radiotherapy (SGRT) can be used, however, commercial SGRT systems are expensive and can require complex installation and calibration procedures. Therefore, there is a need for a cheap and flexible measurement system, to aid the testing and development of new immobilisation devices for RT.

Material/Methods:

The method developed in this work couples (i) paper-based ArUCo markers which can be securely taped to a person’s skin as seen in Figure 1, together with (ii) regular cameras, positioned orthogonally on tripods, to capture images in two planes. Markers fixed onto human subjects can then be used to assess the inter- and intra-fractional repeatability and stability associated with new immobilisation systems.