The Chernobyl experience in the area of retrospective dosimetry

Abstract

The Chernobyl accident, which occurred on 26 April 1986 at a nuclear power plant locatedless than 150 km north of Kiev, was the largest nuclear accident to date. Theunprecedented scale of the accident was determined not only by the amount ofreleased activity, but also by the number of workers and of the general publicinvolved, and therefore exposed to increased doses of ionising radiation. Due to theunexpected and large scale of the accident, dosimetry techniques and practices were farfrom the optimum; personal dosimetry of cleanup workers (liquidators) was notcomplete, and there were no direct measurements of the exposures of membersof the public. As a result, an acute need for retrospective dose assessment wasdictated by radiation protection and research considerations. In response, substantialefforts have been made to reconstruct doses for the main exposed cohorts, using abroad variety of newly developed methods: analytical, biological and physical(electron paramagnetic resonance spectroscopy of teeth, thermoluminescenceof quartz) and modelling. This paper reviews the extensive experience gainedby the National Research Center for Radiation Medicine, Academy of MedicalSciences, Ukraine in the field of retrospective dosimetry of large cohorts of exposedpopulation and professionals. These dose reconstruction projects were implemented, inparticular, in the framework of epidemiological studies, designed to follow-up themedical consequences of the Chernobyl accident and study health effects of ionizingradiation, particularly Ukrainian–American studies of cataracts and leukaemia amongliquidators.