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George, Jyothis

University of British Columbia

FLASH radiotherapy (FLASH-RT) is a promising new approach in the field of radiotherapy that has the potential to transform treatment by delivering radiation at ultra-high dose rates (UHDR) exceeding 40 Gy/s. This technique aims to increase normal tissue tolerance while maintaining the anti-tumoral effects of conventional radiotherapy, potentially reducing side effects without compromising treatment efficacy. The unique benefits of FLASH-RT, such as reduced normal tissue toxicity, have created a need for dosimetry tools that can accurately quantify doses delivered at these extreme rates. However, dosimetry in UHDR environments presents specific challenges, as the rapid delivery can influence detector response, leading to significant errors in dose measurement if not properly managed. A range of passive and active dosimeters have been used to assess UHDR dosimetry, including ion chambers. Ion chambers offer consistent and reliable real-time monitoring, making them the preferred choice in dosimetry of standard dose rate beams, but their response can decrease at ultra-high dose rates, necessitating further characterization for use in UHDR contexts. This study assesses the potential of the IBA Dosimetry CC01 micro-ionization chamber for use in FLASH dosimetry, specifically with electron FLASH beams. A CC01 chamber, paired with a Victoreen Model 530 electrometer, was tested with electron FLASH beams generated by a modified Varian TrueBeam medical linear accelerator. To establish a benchmark, the performance of the CC01 chamber was compared against dose-rate independent alanine dosimeters, which are known for their stable response across various radiation dose rates. The results from the study indicate that the CC01 chamber is reliable for relative dosimetry in electron FLASH beams.

Text

2024-10-24

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/89488

Medical Physics

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/