Development of a personal dosimeter for medical staff wearing radioprotective lead garments

SCK•CEN Mentor

Saldarriaga Vargas Clarita, csvargas@sckcen.be, +32 (0)14 33 88 14

Expert group

Research in Dosimetric Applications

Introduction

Medical staff working in the interventional radiology and cardiology suites are exposed to scattered ionizing radiation coming from the patient. Protection garments like a lead (Pb) apron and thyroid collar are usually worn as personal radiation protection (RP) equipment. This poses a challenge for whole body personal dosimetry because a conventional Hp(10) dosimeter is no longer capable of providing just by itself an acceptable estimation of the effective dose when radioprotective garments (RPG) are used: an Hp(10) dosimeter worn under RPG would underestimate the effective dose, whereas a dosimeter over RPG would result in its overestimation.

Different methodologies have been proposed to estimate the effective dose when RPG are used, like applying a correction factor to the dose of a standard Hp(10) dosimeter worn above or below RPG (single dosimetry, SD), 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, DD); but even with these methodologies it remains a difficult task to provide a good estimate of the effective dose (i.e. a conservative estimate with minimum possible overestimation) under all possible exposure conditions [Jarvinen et al., Rad Prot Dosim. 2008; 129(1-3)].

Objective

The main objective of this internship is to develop a personal whole-body dosimeter suitable for estimating the effective dose while wearing radioprotective garments. A model of such dosimeter has already been designed at the SCK•CEN by means of Monte Carlo calculations, but further improvement of its performance is still possible.

The energy and angular dependence of the effective dose has already been calculated for photon exposure conditions of interest in interventional radiology and cardiology using the Reference Computational Male Phantom of ICRP 110 equipped with 0.5 mm lead garments. These results are used as a reference to evaluate the performance of the new dosimeter, which should provide a conservative estimation of the effective dose with minimum possible overestimation for all the exposure conditions considered.

The idea of this project is to improve the design of current dosimeter elements by, for instance, evaluating the effect of different filter materials, shapes and thicknesses, on the dose received by the radiation detectors of the dosimeter. This will, in turns, determine the dose response of the dosimeter. The energy and angular dependence of the dose estimated by the dosimeter will be investigated for different dosimeter geometries by means of Monte Carlo calculations using the radiation transport code MCNPX (the student will learn how to use this software during the internship). Once the design of the dosimeter has been optimized, a prototype will be built and then tested under different irradiation conditions.

The minimum diploma level of the candidate needs to be

Academic bachelor

The candidate needs to have a background in

Physics