Implications of the ICRU 95 quantities for various personal dosimetry techniques

Abstract

The objective of this work is to assess the photon energy and angular response of various dosimetry systems in terms of the operational quantities for external radiation exposure personal dose, $H_{\text{p}}$, and personal absorbed dose in local skin, $D_{\text{local skin}}$, defined in Report 95 of the International Commission on Radiation Units and Measurements (ICRU). The dosimetry systems in Switzerland offer an opportunity to evaluate the status quo in personal dosimetry, due to variety of techniques employed and the possibility of accessing commissioning data from the various services.

The photon energy and angular responses in terms of the ICRU Report 51 personal dose equivalents $H_{\text{p}}\left(10\right)$ and $H_{\text{p}}(0.07)$ were compiled for the dosimetry systems used by the Paul Scherrer Institute (radiophotoluminescence and direct ion storage), the Lausanne University Hospital (optically stimulated luminescence), the CERN (direct ion storage), Dosilab (thermoluminescence), and the SUVA (thermoluminescence). From this data, the response of the systems to the ICRU Report 95 quantities for whole body dosimetry ($H_p$) and skin dosimetry ($D_{\text{local skin}}$) was calculated using conversion coefficients from air kerma to the respective operational quantities. Regardless of the detector material, whole-body dosimeter design, or technique, each system over-estimated the personal dose, $H_{\text{p}}$, in the low-energy range ($<70$  keV) up to a factor of 3 or 4. The indicated values for the personal absorbed dose in local skin, $D_{\text{local skin}}$, remains within the limits $(0.71-1.67)$. These estimates highlight the impact of the ICRU 95 Report at a country’s scale and prompts discussion regarding potential solutions and challenges.