ESTRO 2022 - Abstract Book

S251

Abstract book

ESTRO 2022

Conclusion We presented a detailed analysis of uncertainties of pCT concepts for pelvic MRgRT. The current workflow depicts dose uncertainties based on bulk density approaches. Both a PBCT and AICT approaches, which bypass the need for a planning CT, might be considered clinically acceptable whilst reducing imaging dose and registration issues. Especially for air influenced OARs the AI-based pseudo-CT generation approach shows a better performance by more accurately predicting the different density gradients.

OC-0290 Sources of errors in radiotherapy as assessed with the IROC lung, H&N and Spine phantoms

S. Edward 1 , C. Peterson 2 , R. Howell 3 , P. Balter 3 , J. Pollard-Larkin 3 , S. Kry 3

1 MD Anderson Cancer Center, Radiation Physics, Houston, USA; 2 MD Anderson Cancer Center, Biostatistics, Houston, TX, USA; 3 MD Anderson Cancer Center, Radiation Physics, Houston, TX, USA Purpose or Objective Phantoms from the Imaging and Radiation Oncology Core (IROC) show 8-17% of institutions fail to deliver the intended dose within established criteria. This work sought to quantify the source and magnitude of various sources of error in treatment delivery. Materials and Methods IROC lung (n = 41), head and neck (H&N) (n = 36) and spine (n = 63) phantoms irradiated by various institutions, as an end- to-end radiotherapy test, were evaluated for quantifiable errors that may occur in the planning and delivery phases of