Application of ALARP cost-benefit analysis to hospital-based radiation protection.

The UK Ionising Radiations Regulations 2017 require employers to restrict radiation doses to their employees and the public to be as low as reasonably practicable (ALARP). This article looks at the boundary between what might be considered to be reasonable and unreasonable in protecting staff and the general public in the field of hospital-based diagnostic radiology. Guidance on cost-benefit analysis in support of ALARP has been used to formulate relationships for the estimation of the cost at which a radiation protection intervention is no longer ALARP. These relationships allow for a direct link between a reduction in radiation exposure and the maximum reasonable ALARP cost of intervention. Application of the approach to hospital-based radiation protection situations show that the ALARP cost limits for protecting radiation workers against the residual risks in the hospital environment are relatively low. Conversely, the ALARP limit to investment in public dose reduction by means of reducing patient doses can be very high.