Establishing local diagnostic reference levels for mini C-arm use in upper limb surgery - A step towards national audit

Abstract

Aims: Under the Ionising Radiation Medical Exposure Regulations, hospitals using fluoroscopy and image intensifiers should monitor doses from exposures using ionising radiation. There is a need for national diagnostic reference levels to advise Orthopaedic and Plastic surgeons on safe screening times and radiation doses for patients having upper limb surgical procedures.

Methods: Retrospective study of all patients who underwent upper limb surgical procedures requiring intra-operative mini C-arm image intensifier use at our hospital between 2013 and 2019. This included results from three machines in different rooms. Procedures were classified as closed and open procedures.

Results: Information on a total of 2910 procedures over 6 years (June 2013 to June 2019) were obtained. 133 procedures with incomplete data and 4 cases of lower extremities were excluded. 1719 closed procedures had a median dose area product of 0.48 cGycm² and median screening time of 7 s, compared to 1054 open procedures, with a median dose area product of 1.88 cGycm² and median screening time of 28 s. National diagnostic reference levels are set at the third quartile and indicate the difference between good and poor practice. For diagnostic reference levels, we suggest a dose area product of 0.82 cGycm² and a screening time of 11 s for closed procedures and a dose area product of 3.07 cGycm² and screening time of 40 s for open procedures. Public Health England state that national diagnostic reference levels should be derived from multiple patients, radiology rooms and hospitals. Our data meets the first two criteria and is an initial step in establishing national diagnostic reference levels for upper limb mini C-arm use.

Conclusions: This large audit reports results, which, with further work across multiple hospital sites, should lead to establishing national diagnostic reference levels for mini C-arm fluoroscopy for upper limb Orthopaedic procedures.

Keywords: Diagnostic reference level; Fluoroscopy; IRMER; Mini C-arm; Upper limb.