Setting up an in-house TL based environmental dose monitoring system for the NM department at a major public hospital

Abstract

Background: Environmental dose monitoring in healthcare institutions is crucial to radiation safety and regulatory compliance. This process falls under the auspices of the radiation protection expert as per Article 82 of the European Directive 2013/59/Euratom. Radiation monitoring often uses third-party dosimeters with limited control over the calibration process. Additionally, further dosimeter irradiation may occur during transportation to the readout entity, leading to possible discrepancies between the measured reading and the real dose. Objectives: The project sought to establish an in-house thermoluminescence-based system for environmental dose monitoring and to perform and analyse an environmental dose monitoring survey of the nuclear medicine department at a major national hospital. Research Methodology: The methodology involved calibrating and validating lithiumfluoride crystals through different radiation sources, theoretical values and realtime dosimeters. After two months of monitoring, the crystals registered the environmental doses present in each area. Doses measured were classified into lowoccupancy, patient, general public, and staff areas. Results: Low-occupancy area doses varied from 1.45 ± 0.34 mSv/yr (cold store) to 20.11 ± 5.03 mSv/yr (hot store). Patient area doses varied from 0.71 ± 0.18 mSv/yr (cadmium zinc telluride scanner room) to 19.86 ± 4.97 mSv/yr (positron emission tomography room). General public area (stress room) doses varied from 0.89 ± 0.22 mSv/yr to 0.91 ± 0.23 mSv/yr. Finally, radiation staff area doses varied from 0.47 ± 0.12 mSv/yr (positron emission tomography control room) to 10.06 ± 2.52 mSv/yr (hot lab). Almost all areas monitored were under dose constraints; the exceptional areas will now have to apply remedial actions to decrease the dose. Conclusions and Recommendations: Setting up an in-house thermoluminescence based environmental dose monitoring system is possible with the right human resources and advantageous for gaining immediate results. The study recommended ongoing calibration, optimisation strategies and research involving machine learning models, environmental dose monitoring standardisation, and cost-benefit analysis for system accreditation.