Room: AAPM ePoster Library
Purpose: of delivered radiation dose is critically important for preclinical radiobiology research studies. Current approach to calculate delivered dose in experiments using an x-ray irradiator is typically based on AAPM-TG61 formalism. However, studies have shown discrepancies between calculated and delivered doses due to lack of sufficient scatter in actual experiments caused by the small animal/phantom sizes. We developed a Monte Carlo (MC) based dose calculation platform to estimate delivered dose for each specific experiment in the total body irradiation (TBI) setup.
Methods: on a user defined input weight of a mouse/rat, we computed the size of the animal using a look-up table and scaled the Digimouse phantom (openly available online). A voxelized phantom of the scaled phantom was then generated. We considered the total body irradiation setup for an x-ray irradiator XRad 320 (PXI, North Branford). The phantom sit on top of a steel plate at 65cm away from the x-ray spot. We commissioned the x-ray source model to match actual photon fluence and spectrum. We computed dose to the phantom using our GPU-based ultrafast MC dose engine. We further recorded average absorbed dose for main organs, such as heart, lung, brain and kidney.
Results: a rat of 24.8 gram in weight, the average dose rate for heart, lung, brain and kidney were 1.02Gy/min, 1.02Gy/min, 1.178Gy/min, 1.267Gy/min, respectively. In a test case with a 28.4 gram rat case, the calculated dose rate to body center was 1.015 Gy/min, in agreement with the actual measured dose rate 1.070 Gy/min. The computation time to reach 1% uncertainty was 2.5 seconds using one GPU card.
Conclusion: developed a fast case-specific dose calculation platform for pre-clinical radiobiology experiments in the TBI seeting, which will facilitate accurate dosimetry of these experiments.
Not Applicable / None Entered.