Design of a personal dosimeter for medical staff wearing radioprotective garments

For the medical staff working in interventional radiology and cardiology personal dosimetry it is fundamental to assess the effective dose received and to respect the dose limits defined by the ICRP. During the procedures the medical staff have to wear radiation protection garments like lead aprons and thyroid collars to shield the radiation scattered from the patient thus reducing the effective dose received. Both the dose received by the physician and the dose absorbed by whole-body dosimeters worn are affected by the presence of the radioprotective lead garments. This study focuses on the development of the design of a new whole-body personal dosimeter for the estimation of the effective dose when wearing lead garments. Starting from a former design, optimized only for transversal irradiation, the dosimeter filters have been added and modified in order to improve the performance also for sagittal irradiation. In the first part of this work the optimization of the design has been carried out through simulations, performed with the Monte Carlo radiation transport code MCNP6.2, with simplified geometries considering parallel photon beams of different energies and angles of incidence. The results of these simulations have been compared to reference values of effective dose with radioprotective garments previously calculated and several changes in the design has been made to improve the overall performance. In the second and final part has been performed more lifelike simulations, considering all the element of the operating room relevant to the analysis, in order to test the performance of the new dosimeter design, obtained with the optimization process. The most common scenarios occurring during the procedures has been simulated to analyze the effects on the estimation of the effective dose to the physicians. This work has been developed in collaboration with the SCK-CEN (Belgian Nuclear Research Center), during a 6 months internship.