Assessment of the impact of an introduction of the ICRU95 dosimetric quantities on radiological protection in Germany

Radiological protection distinguishes between protection quantities and operational quantities:

• Protection quantities serve to assess health risks from ionising radiation to humans.
• Operational quantities are physical quantities that can be directly determined by measurement devices and provide estimates for the protection quantities.

In 2020, the International Commission on Radiation Units and Measurements (ICRU) proposed a new system of operational quantities in order to map the protection quantities more accurately by definition. Since implementation would have far-reaching consequences, in April 2025 the German Commission on Radiological Protection (SSK) was requested to scientifically evaluate the consequences of such an introduction, considering scientific, practical, technical, and economic aspects.

• How should the scientific benefit of the new operational quantities be evaluated?
• What are the consequences for practical radiological protection, and what additional value do the new quantities provide compared to those currently defined by law?
• What is the impact on dosimetry and the production of radiation protection dosemeters?
• What long-term effects are to be expected if the new quantities are not introduced, and how should these be assessed?

• The Commission on Radiological Protection (SSK) recommends not to introduce the new operational quantities as defined in ICRU Report 95 in Germany at this time. If these quantities are not introduced at present, no significant disadvantages are to be expected.
• No practical added value: For practical radiological protection, there are currently hardly any relevant advantages. The existing system is considered well-functioning, intentionally conservative, and provides an adequate level of protection. Typical uncertainties in dose assessment, e.g. due to anatomical variations, mispositioning, or inhomogeneous fields, would persist in the new system as well. The potential reduction in dose values according to the new quantities carries a risk of uncertainty and mistrust, and thus at least require enhanced communication.
• Significant effort required: A transition would require considerable resources. Existing measurement devices, calibration procedures, and data evaluation algorithms would have to be adapted or partially redeveloped. This involves clear technical and economic implications, which would mean significant cost and time expenditure for manufacturers and users. 
• International harmonisation: International coordination is essential. Under the current framework, the SSK recommends maintaining the current system and working towards a harmonised approach with regard to a final decision.