A dose limit for the eye of 20 mSv, as proposed by the ICRP, could be exceeded by interventional clinicians. Data on eye dose levels for interventional radiologists and cardiologists provided by medical physicists from hospitals around the UK have been collated. The results indicate that most hospitals would require one or more interventional clinicians to be classified and several would have exceeded a 20 mSv limit. Dose data in the literature have been reviewed to derive factors that might be used to predict eye dose levels based on dose per procedure or kerma-area product workload. These could be used in prior risk assessments to establish monitoring practice. An alternative approach to personnel dose monitoring in radiology applications using a collar dosimeter worn outside the lead apron as the first dosimeter is proposed. The collar dosimeter would provide an assessment of eye dose in terms of Hp(3) and body dose in terms of Hp(10), which could be divided by ten to provide an assessment of effective dose. If Hp(3) exceeded 1 mSv per month, regular monitoring with a head dosimeter would be recommended, and if Hp(10) exceeded 2 mSv per month, then an under-apron dosimeter should also be worn.

Doses to the eyes of interventional radiologists and cardiologists could exceed the annual limit of 20 mSv proposed by the International Commission on Radiological Protection. Lead glasses of various designs are available to provide protection, but standard eye dosemeters will not take account of the protection they provide. The aim of this study has been to derive dose reduction factors (DRFs) equal to the ratio of the dose with no eyewear, divided by that when lead glasses are worn. Thirty sets of protective eyewear have been tested in x-ray fields using anthropomorphic phantoms to simulate the patient and clinician in two centres. The experiments performed have determined DRFs from simulations of interventional procedures by measuring doses to the eyes of the phantom representing the clinician, using TLDs in Glasgow, Scotland and with an electronic dosemeter in Gothenburg, Sweden. During interventional procedures scattered x-rays arising from the patient will be incident on the head of the clinician from below and to the side. DRFs for x-rays incident on the front of lead glasses vary from 5.2 to 7.6, while values for orientations similar to those used in the majority of clinical practice are between 1.4 and 5.2. Specialised designs with lead glass side shields or of a wraparound style with angled lenses performed better than lead glasses based on the design of standard spectacles. Results suggest that application of a DRF of 2 would provide a conservative factor that could be applied to personal dosemeter measurements to account for the dose reduction provided by any type of lead glasses provided certain criteria relating to design and consistency of use are applied.

Doses to the eyes of interventional clinicians can exceed 20 mSv. Various protective devices can afford protection to the eyes with the final barrier being protective eyewear. The protection provided by lead glasses is difficult to quantify, and the majority of dosimeters are not designed to be worn under lead glasses. This study has measured dose reduction factors (DRFs) equal to the ratio of the dose with no protection, divided by that when lead glasses are worn. Glasses have been tested in X-ray fields using anthropomorphic phantoms to simulate the patient and clinician. DRFs for X-rays incident from the front vary from 5.2 to 7.6, while values for orientations reminiscent of clinical practice are between 1.4 and 5.2. Results suggest that a DRF of two is a conservative factor that could be applied to personal dosimeter measurements to account for the dose reduction provided by most types of lead glasses.