Active dosimetry for VHEE FLASH radiotherapy using beam profile monitors and charge measurements

Journal article

The discovery of the FLASH effect has revealed a high potential for treating cancer more efficiently by sparing healthy tissue. The surge in related medical research activities over the last couple of years has triggered a demand for technology with the capability of generating and measuring ionizing radiation at ultra-high dose-rates (UHDR). A reliable dosimetry system is an integral part of a radiotherapy machine. Because existing active dosimetry methods are unable to handle the dose-rates required for FLASH, UHDR dosimetry has emerged as an important area of research. In this paper we present an active dosimetry method based on a scintillating screen and an integrating current transformer. This method provides a simultaneous measurement of the absolute dose delivery as well as the 2D dose distribution. The measurements have been correlated with corresponding readings from radiochromic films (RCFs), and a procedure for image processing has been established. Moreover, different methods of calibrating the active dosimetry system against RCFs have been introduced and evaluated. Lastly, we present results which demonstrate that an agreement with RCFs of better than 5% can be realistically expected if camera parameters are carefully optimized.

Authors: Rieker, VF; Corsini, R; Stapnes, S; Adli, E; Farabolini, W

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
• Volume: 1069
• Article number: 169845
• Publication date: 2024-09-12
• Acceptance date: 2024-09-04
• DOI: 10.1016/j.nima.2024.169845
• EISSN: 1872-9576
• ISSN: 0168-9002
• Language: English
• Keywords: dosimetry; UHDR; VHEE; radiochromic films; beam profile monitor; YAG