Abstract ID: 73 Design of a personal dosimeter for estimating the effective dose of medical staff when wearing radioprotective garments using Monte Carlo simulations

Abstract

Medical staff performing X-ray-guided interventional procedures is exposed to scattered ionizing radiation. Radioprotective garments (RPG) are usually worn as personal radiation protection equipment. Different methodologies have been proposed to estimate the effective dose when RPG are used ( E RPG ) , like applying a correction factor to the dose of a standard H p (10) dosimeter worn above or below RPG (single dosimetry), or the use of an algorithm combining the dose from two of them: one worn above RPG and the other one worn below (double dosimetry). But even with these methodologies it remains difficult to provide a good estimate of the effective dose ( i . e . a conservative estimate with minimized overestimation) under all possible exposure conditions [1] . This study aimed at designing a personal whole body dosimeter capable of estimating E RPG directly (without the intermediate step of H p (10)) by means of Monte Carlo calculations using MCNPX2.7.0. The ICRP110 reference male phantom was equipped with a mathematically-defined 0.5 mm-thick lead apron and collar and its effective dose ( E RPG ) was calculated for photon beams with energies in the range of interest in interventional procedures (20–120 keV) and angles of incidence (−60° to +60°) parallel to the transverse plane of the body. The design of the new dosimeter should be such that its energy and angular response is as similar as possible to that of the calculated E RPG . The following design parameters have been considered in the simulations: material composition, thickness and geometry of elements around the detector and type of dosimetric detectors. Current status of the design process and some of the steps needed to reach this status are presented. The photon energy and angular dependences are shown for two dosimeter models consisting of two radiosensitive detectors with different filtration: a simplified model based on thermoluminescent detectors and a more realistic model based on glass radiophotoluminescent detectors. For both dosimeters the energy and angular dependence of the combined dose from the two detectors is usually within ± 20% of the calculated effective dose E RPG .