Directional vector-based quick evaluation method for protective plate effects in X-ray fluoroscopy (DQPEX)

Hizukuri, Kyoko*; Fujibuchi, Toshio*; Han, D.*; Arakawa, Hiroyuki*; Furuta, Takuya   

One of the radiation protection measures for medical personnel engaged in X-ray fluoroscopy is the use of radiation-protective plates and a simulation tool to evaluate effect of the plates is desired. Monte Carlo simulation has an advantage of being able to accurately calculate the interaction between radiations and various objects present in the X-ray room. However, Monte Carlo simulation has a disadvantage of being computationally time-consuming. Therefore, we developed a new simplified method to calculate the dose distribution in a short time with the presence of protective plates using pre-computed directional vectors (SCV). Using the Monte Carlo code PHITS, we simulated the ambient dose equivalent distribution the X-ray fluoroscopy room without the presence of protective plates. Assuming the dose at each voxel was all contributed from radiations in the direction indicated by the directional vector, the shielding effect of the protective plates for the dose at the voxel was determined whether the line toward backtrace of the directional vector has a intersect with the protective plate or not. With SCV, the computational time for the whole dose distribution with the presence of a protective plate was reduced approximately 1/6000 of the full PHITS simulation keeping the good accuracy to evaluate the effect of the plate.