Evaluating the Effectiveness of Extremity Dose Monitoring Mechanisms within UK Radiopharmacy Units

Introduction

All UK individuals are exposed to a degree of ionising radiation however, for those working within a Radiopharmacy this risk is increased and particularly apparent to the extremities of the hand. Extremity dose monitoring is outlined by the HSE, although no standardised mechanism of monitoring is defined. Current literature displays that a large dose gradient is achieved across an operator’s hand, making measured dose dependent on the monitoring position employed. If inadequately controlled, this has the potential to result in the systemic underestimation of operators true maximal IR exposure.

Objective

It is the aim of this study to investigate the effectiveness of extremity dose monitoring mechanisms utilised within UK Radiopharmacy units.

Methods

Internal study centre evaluations quantifying this dose gradient are to be employed. An extremity monitoring survey is to be distributed via the UKRG network with measured doses compared dependent on monitoring position. Internally derived correction factors are to be applied to reported doses to estimate the true maximal exposure within UK Radiopharmacy units.

Results

A significant difference (P>0.05) in measured dose was observed for monitoring provisions employed on the dominant and non-dominant hand. For two out of three operators the index fingertip displayed the highest measured dose. However inter-operator variability impaired statistical significance for dispensing operators. Overall, a large degree of variance was observed in UK monitoring techniques however, all reported doses (n=109) were within HSE limits. Upon application of internally derived scaling factors, two operator doses exceeded classification limit. When employing literature derived worst-case factors, it was estimated that 5.5% of individuals may unknowingly exceed the 500mSv limit as a result of inadequate monitoring technique.

Conclusion

A significant dose gradient is achieved across the hand of Radiopharmacy operators however, there are several contributory factors which result in variability across operators making defining a standardised factor challenging. Departments are recommended to take a risk-based approach to extremity monitoring provisions in order to best determine the true level of operator ionising radiation exposure.