Implementation of eye-lens dosimetry in Poland

It has been seven years from the ICRP Statement on tissue reactions containing the recommendations for an equivalent dose limit for the lens of the eye of 20 mSv per year for workers (ICRP, 2012), and has been 7 years since Laboratory of Individual and Environmental Dosimetry (LADIS) introduced in practice eye lens doses measurement. The reduction of the limit for occupational exposure for the lens of the eye needs adequate approaches for eye protection and eye dose monitoring. The most accurate method for monitoring the equivalent dose to the lens of the eye is to measure the personal dose equivalent Hp(3) with a dedicated dosimeter worn as close as practicable to the eye. To measure eye lens doses in terms of this quantity a dosemeter and an appropriate method has been introduced in the largest dosimetry service in Poland. This paper presents historically the introduction of eye lens dosimetry in routine measurements and an analysis of the exposure results of the eye lens dose sl. Results of measurements of Hp(3) from eye lens dose-meters (almost 5000 quarterly readouts), issued in the years 2012-2018 were reported. In measurements EYE-D (TM) dosemeter developed within ORAMED EU project (Vanhavere et al., 2011) and high-sensitivity MCP-N (LiF:Mg, Cu, P) thermoluminescence detectors were used. The frequency distribution of eye lens dose measurements performed using specially dedicated dosemeters, via their Hp(3) operational values, over 3-month periods, after subtraction of natural background in 74% cases are below 0.1 mSv. In the case of the new operational quantity, Hp(3) the number of workers, which exceed the new limit during 7 years monitoring period was 48 (1%). The study showed considerable uncertainties associated with the assessment of eye lens dose from the commonly used whole body dosemeters on the chest in terms of Hp(10) and ring dosemeters on the finger which measures skin doses in terms of Hp(0.07). Therefore, only monitoring of the eyes with specific dosemeters for yearly follow-up can provide accurate annual doses.