ESTRO 2022 - Abstract Book

S1366

Abstract book

ESTRO 2022

Results Dose to film in the abdominal region of the Gray and White mice phantoms compared within 3.2%. Uncertainty based on the standard deviation of the mean (SDOM) of three independent repetitions was 2.3% Dose to alanine in the abdominal region of the Brown and White phantoms agreed within 2.1% with 0.6% uncertainty. Film and alanine dose at approximately the same position in the abdominal region of the White phantom, agreed within 2%. On average (both detectors and three phantoms), the dose rate (DR) (measured dose/irradiation time) to a point in the mid plane of the mouse in the abdominal region was 2.7 Gy/min. The DR currently used to calculate TBI irradiation times within our institute (based on 2018 measurements with an inadequate dosimetric system) was 2.37 Gy/min.

Conclusion Previous to this work, the dose delivered during TBI irradiations was 13% larger than required. The DR previously used to calculate irradiation times did not consider the differences between reference output measurement conditions and real setup of mice during TBI experiments. A standardized protocol with a detailed description of the irradiation conditions and table for time calculation is now routinely used.

PO-1585 End-to-end verification of DIBH Treatment technique using CIRS Dynamic Thorax phantom

S. Pillai 1 , N. McInally 1 , A. Lambert 2 , Z. Monteith 2 , F. Robertson 2 , D. Sutton 3 , W. Nailon 4 , Z. Huang 5

1 Ninewells Hospital & Medical School, Medical Physics, Dundee, United Kingdom; 2 Ninewells Hospital & Medical School, Radiotherapy, Dundee, United Kingdom; 3 University of Dundee, Medical Physics, Dundee, United Kingdom; 4 University of Edinburgh, Medical Physics, Dundee, United Kingdom; 5 University of Dundee, Biomedical Engineering, Dundee, United Kingdom Purpose or Objective Deep Inspiration Breath Hold (DIBH) technique is most commonly used when treating left-sided breast cancer due to the potential reduction in cardiac toxicity. Though this technique has been in clinical use since 2012, patient specific dose verification is not well established and also not widely reported in the literature. The aim of this study is to address this and to provide a method for identifying the dose delivered from DIBH technique involving gated fields using individual patients’ breathing traces.

Materials and Methods