Establishing local diagnostic reference levels for common orthopaedic procedures using the mini C-arm fluoroscope

Mini C-arm fluoroscopes are widely used by orthopaedic surgeons for intraoperative image guidance without the need for radiographers. This puts the responsibility for radiation exposure firmly with the operating surgeon. In order to maintain safe and best practice under U.K. Ionising Radiation (Medical Exposure) Regulations, one must limit radiation exposure and audit performance using national diagnostic reference levels (DRLs). In the case of the mini C-arm, there are no national DRLs. IR(ME)R, therefore, require the establishment of local DRLs by each hospital to act as an alternative guideline for safe radiation use. The aim of our audit was to establish local DRLs based on our experience operating with the use of the mini C-arm over the last 7 years.

This retrospective audit evaluates the end dose-area product (DAP) recorded for common trauma and orthopaedic procedures using the mini C-arm in a busy district general hospital.We present the quartile data and have set the cut-off point as the third quartile for formulating the local DRLs, consistent with the methodology for the conventional fluoroscope.

For our data set (n = 1664), the third quartile DAP values were lowest for surgeries to the forearm (5.38 cGycm²), hand (7.62 cGycm²), and foot/ankle (8.56 cGycm²), and highest for wrist (10.64 cGycm²) and elbow (14.61 cGycm²) procedures.

To our knowledge, this is the largest data set used to establish local DRLs. Other centres may find our guidelines useful whilst they establish their own local DRLs.