Dosimetry

The staff participating in this study used a new dedicated direct eye lens dosimeter (eye dosimeter), the DOSIRIS^™ (IRSN, France), which specifically measures the eye lens dose [Hp(3)]¹². The eye dosimeter consists of a thermoluminescent dosimeter sensor (⁷LiF:Mg, Ti), plastic capsule, and adjustable headset. The laboratory at IRSN supplied and calibrated the eye dosimeters. Following each 1-month measurement period, the eye dosimeters were returned to IRSN in France to be read. Dose calibration was performed in IRSN by reference to the national standard.

All IC staff wore an eye dosimeter just lateral to the left eye. The nine IC physicians who used Pb glasses wore an additional eye dosimeter outside the Pb glasses close to their left eye (Fig. 1). We also estimated the eye dose in all IC staff using a neck personal dosimeter (Fig. 1). The commercial neck personal dosimeter used was a silver-activated phosphate glass dosimeter [0.07-mm dose equivalent, Hp(0.07), Glass Badge, Chiyoda-Technol, Japan), which was worn outside the personal Pb apron to the left of the neck. The glass badges were returned monthly to Chiyoda Technology for evaluation.

The positions of the dosimeters used during the procedures. The eye dosimeter (DOSIRIS) was worn just lateral to the left eye, and the personal dosimeter (badge) was worn outside the Pb apron to the left of the neck (A). In the nine physicians using Pb glasses, an additional eye dosimeter (DOSIRIS) was worn outside the Pb glasses close to the left eye (B).

We evaluated the protective effects of Pb glasses in nine physicians by placing eye dosimeters inside and outside the glasses (three physicians did not wear Pb glasses). We also measured the correlation between the eye dose [Hp(3)] and the neck dose [Hp(0.07)] to explore whether it was feasible to estimate the eye dose using a neck dosimeter.

We also determined the estimated annual eye dose (EAED) as follows: