Measurement of the whole body, eye lens and extremity occupational exposures in nuclear medicine staff at King Chulalongkorn Memorial Hospital

Abstract

Due to the epidemiology evidence of cataract and eye lens opacity, ICRP Publication 118 in 2012, recommended the new eye lens dose limit of occupational exposure at 20 mSv/year, averaged over 5-year periods, no single year exceeding 50 mSv. For the public eye lens dose limit is 15 mSv/year. After ICRP changed the eye lens dose limit, many reports on eye lens dose measurement using thermoluminescent dosimeter (TLD) from interventional radiologists and interventional cardiologists were published. Few reports on eye lens dose measurement in nuclear medicine (NM) personnel were found.

The primary objective of this study is to measure whole body; Hp(10), eye lens; Hp(3), and finger; Hp(0.07) using Optically Stimulated Luminescent Dosimeter (OSLD) in ten NM staff which consists of one radiopharmacist, two radiochemists, five technologists, and two nurses who prepare, dispense, and inject radiopharmaceuticals, and scan patients at King Chulalongkorn Memorial Hospital (KCMH) for six months (March-August 2019). The second objective is to analyze the correlations between the Hp(10), Hp(3), and Hp(0.07).

Three sets of OSLDs were attached at whole body, eye lens (left and right), and finger of 10 nuclear medicine staff. The average and range of Hp(10), Hp(3)Lt, Hp(3)Rt, and Hp(0.07) were 1.73 (0.84-3.44), 1.19 (0.20-4.66), 1.24 (0.25-4.62), and 29.22 (1.13-261.83) mSv/year respectively. The correlations between the Hp(3)Lt VS Hp(10), Hp(3)Rt VS Hp(10), Hp(0.07) VS Hp(10), Hp(3)Lt VS Hp(0.07), and Hp(3)Rt VS Hp(0.07), excluding radiopharmacist were 0.54 (p-value = 0.14), 0.58 (p-value = 0.11), 0.46 (p-value = 0.21), 0.03 (p-value = 0.93), and 0.12 (p-value = 0.76) respectively. There was no correlation among five pairs because of all p-values were higher than 0.05.

The measurements of occupational exposures were less than the new ICRP dose limit and the study on the relation between the Hp(10), Hp(3), and Hp(0.07) can be concluded that the eye lens dosimeters are not required for NM staff at KCMH as they felt inconvenient wearing eye lens dosimeters. Whole body and finger dosimeters must be routinely used to monitor personnel dose, especially for radiopharmacist due to his high finger dose at 261.83 mSv/year. Eye lens dose could be estimated from the whole body or finger dose of the same person.