A systematic approach for estimating ICRU Report 95 operational quantities for personnel monitoring using a 3-element TLD badge system

The introduction of International Commission on Radiation Units and Measurements (ICRU) Report 95 marks a revision of operational quantities (OQs) for individual monitoring due to external radiation exposures. This revision has a major impact, particularly in low photon energy range (20-100 keV), where the conversion coefficients of existing [(<i>H</i>_p(10)] and new [(<i>H</i>_p)] OQs for whole body dose differ by a factor up to 5. The shift from<i>H</i>_p(10) to<i>H</i>_pposes considerable challenges for its integration into existing personnel dosimetry systems. This is particularly relevant to the diagnostic radiology sector, where photon energies predominantly range between 20 and 100 keV and approximately 70% of monitored occupational workers are from this sector. In this context, the present study investigates the feasibility of implementing the updated OQs for multi-element passive dosimetry systems, such as CaSO₄:Dy-based thermoluminescent dosimeters and outlines a systematic approach. Three approaches were demonstrated for the implementation of<i>H</i>_p: a linear equation-based method, a non-linear equation approach, and a multi-stage machine learning model. The results indicate that all methods achieved promising accuracy in dose estimation, with the machine-learning model exhibiting a slight advantage. Notably, approximately 99% of the estimated doses fell within ±30% of the actual delivered dose, underscoring the reliability of these approaches for practical application. The present study highlights the distinct advantage of multi-element passive dosimeters, demonstrating their capability to accommodate<i>H</i>_pwithout necessitating significant design modifications. Through a systematic approach for estimating<i>H</i>_p, this study establishes the efficacy of multi-element passive dosimeters as a viable solution for the implementation of ICRU-95 OQs in personnel monitoring systems.