Dosimetric Radiation Protection Quantities - Impact of the Forthcoming ICRP Recommendations

The physical quantities namely fluence, kerma and absorbed dose provide the base for the operational and the protection quantities. The absorbed dose continues to be the fundamental physical quantity for the radiological protection. The most striking feature relating the quantities in the forthcoming recommendations is the updating of the radiation and tissue weighting factors based on the latest available scientific information on radiobiology and the physics of radiation exposure. This is bound to make a significant impact in arriving at the equivalent doses and effective dose. For external exposures of neutrons, the forthcoming recommendations are going to improve the relationship between the operational and protection quantities. The changes in the tissue weighting factors of some tissues / organs, the inclusion of several new tissues / organs for the consideration of tissue weighting factors and the use of the proposed Reference Male and Reference Female voxel phantoms would require new conversion coefficients and dose coefficients for external and internal exposures. The other striking feature appears to be the details of the concepts to ensure that the protections quantities are used for the appropriate and intended purposes only and the misuse is avoided.