ESTRO 2022 - Abstract Book

S695

Abstract book

ESTRO 2022

Geometric inaccuracy was 0.48±0.24 mm with the 99 th percentile being 1.21 mm. Results were very stable over time, with an average intra-site standard deviation of 0.03 mm. For one system, PIQT analysis found SNR decline of the transmit body coil, which was replaced after 10 months of operation. Mean values post-replacement differed significantly (p<0.0001). Conclusion The vendor-provided PIQT tests capture many parameters that can reveal performance decline of components, but measurements are limited to a small field of view. Considering the dosimetric importance of the patient outline, larger phantoms are required to characterize the geometric accuracy of the MR images. We found all QA tests highly stable over time unless hardware components were exchanged. Most tests were highly comparable between sites with the exception of B 0 homogeneity as a function of gantry angle due to site-specific shimming.

OC-0777 MR-guided lung SBRT: consultation, simulation and treatment delivery in a single day

M.A. Palacios 1 , S. Verheijen 1 , C.J. Haasbeek 1 , R. de Moes 1 , O. Bohoudi 1 , F.L. Schneiders 1 , A.M. Bruynzeel 1 , B.J. Slotman 1 , F.J. Lagerwaard 1 , S. Senan 1 1 Amsterdam UMC, VUmc location, de Boelelaan 1117, 1081 HV Amsterdam, Department of Radiation Oncology, Amsterdam, The Netherlands

Purpose or Objective