5. Dose Recording (DRLs)
A key part of optimization is the use of diagnostic reference levels (DRLs), first proposed by the ICRP in 1996 and most recently updated in ICRP 135 (2018). DRLs are the Commission’s term for a form of investigation level, a dose value above which routine imaging should not exceed for standard-sized patients. Importantly, DRLs do not apply to individual patients. A DRL is a supplement to professional judgement and does not provide a dividing line between good and bad medical practice, however all radiographers / radiologic technologists should be familiar with DRLs as they can assist in identifying exposures that are unusually high or unusually low.
DRLs may exist at both a local and national level so it is important that radiographers are aware of DRL values for common examinations for their region. To best use DRLs, radiographers / radiologic technologists need to be familiar with typical doses, which are often displayed via Dose Area Product (DAP) meters attached to x-ray units or via digital exposure indices/deviation indexes. Knowing the standard dose for an exam and body type in a local setting coupled with the associated DRL value can promote improvement in radiation protection for patients.
Fig. 1 Radiographers with mobile digital x-ray unit and image receptor.