SU‐C‐224‐01: 3D Dosimetry with Gels and Optical Tomography of Dynamic MLC Tracking Based on an Electromagnetic Transponder System

摘要: Purpose: Complex treatment methods such as rotational intensity modulated radiotherapy (rIMRT) offer highly conformal dose delivery but are at risk of being compromised due to target motion. Dynamic MLC tracking has been developed compensate for motion online. Due the complex 3D patterns tumourmotion, would benefit from a full dosimetric verification. In this study we have therefore investigated use dosimetry ‐ with gels and optical tomography measuring effect on distributions clinically measured prostate trajectory. Methods: Two normoxic polyacrylamide geldosimeters were irradiated same rIMRT plan, delivered without while placed stage that reproduced patient A reference geldosimeter was or tracking. performed using an electromagnetic transponder system (RayPilot, MicroPos AB, Gothenburg Sweden). After experiments in two read‐out CT scanner compared stationary dosimeter 3 %/3 mm gamma analyses. Results: 2D 3%/3mm analyses equidistant slices separated by 1 cm transverse plane coronal dosimeters. The weighted average fail‐rate improved 37% 14% (transversal plane) 30% 9% (coronal Conclusions: Optical is valuable tool quantify impact compensation distribution moving target. Improved knowledge about obtained (i) three‐dimensional nature measurements (ii) high resolution competing techniques.