ESTRO 2021 Abstract Book

S780

ESTRO 2021

Conclusion A 2-beams approach could lower ocular radiation-induced toxicities, especially for critical posteriorly-located uveal melanomas. The two beams could be applied on the same day or alternative days.

PD-0937 Reference dosimetry in image guided preclinical irradiators with a small volume ionization chamber I. Silvestre Patallo 1,2 , D. Maughan 3 , R. Carter 4 , A. Nisbet 5 , G. Schettino 3 , G. Schettino 6 , A. Subiel 3 1 National Phyical Laboratory, Medical Radiation Physics, Teddington, United Kingdom; 2 University College London , Medical Physics and Biomedical Engineering, London, United Kingdom; 3 National Physical Laboratory, Medical Radiation Science, Teddington, United Kingdom; 4 University College London (UCL), Cancer Institute, London, United Kingdom; 5 University College London (UCL), Medical Physics and Biomedical Engineering, London, United Kingdom; 6 University of Surrey, Physics, Guildford, United Kingdom Purpose or Objective A number of translational radiation studies have been difficult to replicate [1]. Lack of harmonization in dosimetric methods and challenges implementing dosimetric protocols designed for clinical orthovoltage radiotherapy devices, undermines reproducibility of the results [2]. Image guided preclinical irradiation platforms (IGPIP) deliver small fields in the medium energy x-ray range. Commissioning of devices, followed by dosimetry verification of treatment planning system (TPS), is performed with gafchromic films, involving separate calibration and post-processing. This study characterized a small volume ionization chamber (IC), traceable to a primary standard, in medium energy x-rays for its use for reference dosimetry in small fields delivered by IGPIPs Materials and Methods