Determination of 3D scattered radiation distributions from the Zubal Phantom as a function of LAO/RAO and CRA/CAU gantry angulation

摘要

The purpose of this study is to investigate how the scattered radiation distribution in the interventional procedure room varies with changes in cranial/caudal (CRA/CAU) and right anterior oblique/left anterior oblique (RAO/LAO) gantry angulation of a C-Arm fluoroscopic system to aid in staff dose management. The primary x-ray beam of a Toshiba Infinix fluoroscopy machine was modeled using EGSnrc (DOSXYZnrc) Monte Carlo code and the scattered radiation distributions were calculated using 5 × 10~9 photons incident on the Zubal computational phantom. The Zubal phantom is derived from a CT scan of an average adult male and is anthropomorphic with internal organs. The results show that substantial changes in the scatter dose are possible for the interventionalist next to the table with Cranial/Caudal and RAO/LAO angle variations. For frontal projections the largest change with CRA/CAU angle occurs below the table height, increasing by 50% at the position of the interventionalist next to the table for a 30 degree cranial angulation compared to a caudal angulation for a beam directed toward the abdomen. The scattered radiation distribution also is shown to change with different body regions such as the chest and abdomen. A library of 3D scatter dose-rate distributions is being developed to be implemented in a scatter display system for increased staff awareness of dose levels during procedures.