A comparison of patient skin doses before and after replacement of a neurointerventional fluoroscopy unit

After several embolization patients presented with radiation-induced skin injury in our neuroradiology centre, replacement of the centre's interventional fluoroscopy unit was prioritized. The aims of the present study were to compare the maximum skin dose delivered to each patient by the old and new units, to devise a method of estimating skin dose from the displayed dose-area product and to set local reference doses.

On the old unit, skin dose was measured using thermoluminescent dosimeters on 12 patients undergoing Gugliemi detachable coil embolization. Similar skin dose measurements were undertaken and the dose-area product was recorded for a further 12 patients on the new unit.

The maximum skin dose measured on each patient on the old and new units had a mean of 2.2 Gy and 0.47 Gy, respectively, and a maximum of 4.1 Gy and 1.0 Gy, respectively. Maximum dose delivered to patients' skin by the new equipment was less than a quarter of the dose from the old equipment (p < 0.0001).

The large reductions in skin dose reduced the risk of patients suffering radiation injury and confirmed the validity of replacing ageing interventional fluoroscopy equipment with modern equipment that incorporates dose management systems. As patient skin dose was correlated with dose-area product, local reference dose levels were set in terms of dose-area product; this enabled the operator to monitor the likely maximum patient skin dose during embolization procedures. Other centres could use a similar method to set their own reference doses.