Simulation study of a novel small animal FLASH irradiator (SAFI) with integrated inverse-geometry CT based on circularly distributed kV X-ray sources

• Published in: Scientific reports Vol. 13; no. 1; p. 20181
• Main Authors: Tan, Yuewen, Zhou, Shuang, Haefner, Jonathan, Chen, Qinghao, Mazur, Thomas R, Darafsheh, Arash, Zhang, Tiezhi
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 17.11.2023; Nature Portfolio
• Subjects: Animals; Computed tomography; Finite element method; Irradiation; Monte Carlo Method; Monte Carlo simulation; Phantoms, Imaging; Radiation Dosage; Radiation therapy; Radiometry; Radiotherapy Dosage; Target spot; Toxicity; Tungsten; X-Ray Microtomography; X-Rays
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-47421-0

Ultra-high dose rate (UHDR) radiotherapy (RT) or FLASH-RT can potentially reduce normal tissue toxicity. A small animal irradiator that can deliver FLASH-RT treatments similar to clinical RT treatments is needed for pre-clinical studies of FLASH-RT. We designed and simulated a novel small animal FLASH irradiator (SAFI) based on distributed x-ray source technology. The SAFI system comprises a distributed x-ray source with 51 focal spots equally distributed on a 20 cm diameter ring, which are used for both FLASH-RT and onboard micro-CT imaging. Monte Carlo simulation was performed to estimate the dosimetric characteristics of the SAFI treatment beams. The maximum dose rate, which is limited by the power density of the tungsten target, was estimated based on finite-element analysis (FEA). The maximum DC electron beam current density is 2.6 mA/mm , limited by the tungsten target's linear focal spot power density. At 160 kVp, 51 focal spots, each with a dimension of [Formula: see text] mm and 10° anode angle, can produce up to 120 Gy/s maximum DC irradiation at the center of a cylindrical water phantom. We further demonstrate forward and inverse FLASH-RT planning, as well as inverse-geometry micro-CT with circular source array imaging via numerical simulations.