ESTRO 2024 - Abstract Book

S3225

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

consecutive days was better than 1.6% and the energy indicator was stable within 2.7%. The energy indicator did not show any dependence with PRF but decreased at lower PW (-5.0% between 2 µs and 0.5 µs). Based on the percent depth dose curves, R90 and R50 were shown to be equal to 2.7 cm and 3.8 cm respectively for the 10 cm applicator. Cross profiles measured at 1.5 cm in depth demonstrated a symmetry of the dose distribution of 3.3% and 3.1% and a flatness of 4.2% and 2.9% with the 10 cm and the 5 cm applicators respectively. The dose measured at the depth of maximum dose on beam axis for the 10 cm and 5 cm applicators were respectively equal to 1.28 Gy per pulse and 1,90 Gy per pulse (PW = 2 µs). These results indicated an average dose rate superior to 120 Gy/s up to 3 cm in depth at a PRF of 100 Hz.

Conclusion:

This study summarizes the performances of the 10 MeV UHDR beam of the new FLASHKNiFE system. These characterization tests are the first preparatory step before clinical commissioning. The device will then be used in a clinical trial with the aim of obtaining CE marking.

Keywords: FLASH radiotherapy, beam commissioning

References:

[1] IEC international standard 60976. Medical electrical equipment – Medical electron accelerators – Functional performance characteristics. Edition 2.0 - 2007-10. 2007.

[2] Technical report IEC 60977: Medical electrical equipment – Medical electron accelerators – Guidelines for functional performance characteristics. 2008.

[3] Jaccard et al. High dose-per-pulse electron beam dosimetry: Usability and dose-rate independence of EBT3 Gafchromic films. Med. Phys. 2016.

[4] Marinelli et al. A diamond detector based dosimetric system for instantaneous dose rate measurements in FLASH electron beams. Phys. Med. Biol. 2023.

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Digital Poster

Neutron doses to staff and comforters from clinical treatments in proton therapy centres

Marijke De Saint-Hubert 1 , Maite Romero-Expósito 2,3 , Malgorzata Liszka 2 , Van Hoey Olivier 1 , Sita Pinasti 1 , Lara Struelens 1 , Linda Eliasson 4 , Jan Lillhok 4 , Carles Domingo 5 , Alexandru Dasu 2,6 1 SCK CEN, Research in Dosimetric Applications (RDA), Mol, Belgium. 2 Skandion, Clinic, Uppsala, Sweden. 3 Karolinska Institutet, Oncology Pathology Department, Stockholm, Sweden. 4 SSM, Swedish Radiation Safety Authority, Stockhold,