Commissioning an ultra-high-dose-rate electron linac with end-to-end tests

Area of Science:

• Medical Physics
• Radiotherapy Research
• Preclinical Research

Background:

• The FLASH effect offers potential to improve radiotherapy's therapeutic ratio using ultra-high-dose-rate (UHDR) irradiation.
• Translational research in UHDR-RT is ongoing, with the Mobetron device supporting both UHDR and conventional dose rates for FLASH studies.

Purpose of the Study:

• To present the commissioning of an UHDR Mobetron system.
• To develop and validate end-to-end tests for preclinical UHDR-RT research.

Main Methods:

• Commissioning of UHDR electron beams using a 3D-printed water tank and radiochromic films to characterize beam properties.
• Development of a GAMOS Monte Carlo toolkit beam model using commissioning data.
• Validation of the preclinical FLASH irradiation workflow through end-to-end tests on a 3D-printed mouse phantom.

Main Results:

• Precise measurements of depth dose distributions (PDDs), profiles, and output factors were achieved.
• Increasing pulse width (PW) affected Dmax and R50, while pulse repetition frequency (PRF) had minimal impact on beam characteristics.
• End-to-end tests demonstrated good agreement between Monte Carlo calculations and phantom measurements (Gamma index >93% for 2mm/2% criteria).

Conclusions:

• The commissioned UHDR Mobetron is a suitable tool for preclinical FLASH research.
• The validated beam model and workflow meet the requirements for translational FLASH research.