ICRU Report 95: new operational quantities for external radiation exposure

Measurable operational dose quantities approximate the protection quantities for external exposure, which can generally not be measured directly. In 2020, the International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU) have jointly published ICRU Report 95 with improved definitions for operational quantities, and with conversion coefficients for a wide range of particles and energies. For whole-body exposure, personal dose H p and ambient dose H* are the new operational quantities approximating effective dose E. They are based on the same phantoms and weighting coefficients as E and provide a better approximation of the protection quantity as well as a simplification of the system of radiation protection dose quantities. The paper briefly explains the definition of the new operational quantities It then analyses which changes in practical radiation protection and dosimetry are implied by the future introduction of these quantities.