EPR Dosimetry of Chernobyl Liquidators

The paper is devoted to review of development and application of EPR dosimetry with teeth in Ukraine. It deals with specific features of the EPR dosimetry protocol, which was developed and is practically used in SCRM for retrospective dosimetry of clean-up workers (liquidators). Extensive methodological research was conducted in SCRM in order to develop an original version of EPR dosimetric protocol as well as to investigate the effects caused by confounding factors and develop approaches to their account and mitigation. The proposed EPR dosimetric protocol addresses the demand for high accuracy and reproducibility, low sensitivity threshold as well as high throughput of the technique. High qualities of SCRM version of EPR protocol were proven in the course of elaborate quality assurance program, which included a series of international intercomparisons. Creation and continuous operation of the nationwide tooth acquisition network is another key to the success of EPR dosimetry in Ukraine. Particular attention in the paper is paid to definition of the most optimal way of application of EPR dosimetry for dosimetric support of the post-Chernobyl medical follow-up. The main applications of EPR dosimetry in Ukraine are both routine high precision reconstruction of doses to Chernobyl clean-up workers and the use of EPR dose estimates as a reference dose for validation of other retrospective dosimetry techniques. The latter proved to be the most efficient application of EPR dosimetry in the post-Chernobyl situation. EPR dosimetry was used for testing such methods of retrospective dosimetry as FISH, ADR, SEAD and RADRUE. Nowadays EPR dosimetry plays inevitable role in dosimetric support of the post-Chernobyl medical follow-up studies. Introduction The Chernobyl accident and obvious failure of routine dosimetric monitoring of clean-up workers (liquidators) had stimulated significant development of various methods of retrospective dosimetry. Among those methods one of the most adequate proved to be an EPR dosimetry with teeth. Over last decade EPR dosimetry made all way from unique experimental technique to the tool of routine dose reconstruction. Many different applications are known for EPR dosimetry with teeth. It was used for determination of doses received in course of radiotherapy [1], dose reconstruction for atomic workers [2] as well as in several cases of accidental exposure [3-7]. In recent years, several review papers [8-11] and one book [12] were published dealing with various aspects of EPR dosimetry. Notable role in the process of development and implementation of this method belongs to the research performed in Scientific Center for Radiation Medicine (SCRM) AMS Ukraine, in particular to the work performed in collaboration with leading laboratories worldwide [8, 13-21]. This paper is dealing with some specific features of the EPR dosimetry protocol which was developed and is practically used in SCRM, briefly touches results of investigations performed in this institute, and concentrates to a larger extent on practical applications, which EPR dosimetry had found in Ukraine. Particular attention in the paper is paid to definition of the most optimal way of application of EPR dosimetry for dosimetric support of the post-Chernobyl medical follow-up.