A regulatory perspective on whether the system of radiation protection is fit for purpose.

The system of radiation protection has its origins in the early efforts to protect people from x rays and radium. It was at the Second International Congress of Radiology in Stockholm in 1928 where the first radiation protection recommendations were adopted. The system of protection steadily evolved as new sources of exposure arose and understanding of radiation-related health risks improved. Safeguarding against these risks has required regulators to set enforceable (i.e. measurable) standards. From erythema dose to tolerance dose, critical organ dose to effective dose equivalent, and now effective dose, the units used to set these limits have evolved along with the science underpinning them. Similarly, the definition of the person or group being protected has changed - from Standard Man to Reference Man to Reference Person, with age and gender differences now considered explicitly. As regulators look towards implementing the changes in the 2007 Recommendations of the International Commission on Radiological Protection (ICRP), there remain questions about how to translate an optimisation-based system of constraints and reference levels into the more familiar regime of enforceable limits. Nevertheless, as the new ICRP Recommendations are refinements of a system that did the job it was designed to do more than adequately, so too will the new system of radiation protection be fit for purpose.