Registry for Chronic Radiation Sickness in a Cohort of Mayak PA Workers Exposed to Ionizing Radiation

Abstract

Purpose: To present descriptive characteristics, and structure of the chronic radiation sickness (CRS) registry prospects of its use. Materials and methods: A registry for CRS diagnosed in workers of the nuclear production facility Mayak Production Association (PA) throughout the follow-up period of 1948–2018 was established within a medical and dosimetry database ‘Clinic’ of the Southern Urals Biophysics Institute. Results: The CRS registry includes 2068 cases: 1517 (73.4 %) in males and 551 (26.6 %) in females. Almost all workers (97.9 %) with CRS were hired at the Mayak PA in 1948–1954 and chronically externally and/or internally exposed to ionizing radiation. At a date of CRS diagnosis the mean cumulative red bone marrow absorbed dose of external exposure to gamma rays was 1.1 ± 0.7 Gy in males and 1.0 ± 0.6 Gy in females; the mean annual dose was 0.46 ± 0.33 Gy and 0.38 ± 0.22 Gy in males and females, respectively; maximum annual dose was 0.67 ± 0.46 Gy and 0.55 ± 0.34 Gy in males and females, respectively. The CRS frequency in the Mayak PA worker cohort significantly increased with the cumulative and mean annual RBM absorbed dose of external exposure to gamma rays. In the meantime, the CRS frequency was not associated either with a dose of external neutron exposure or with a dose of internal exposure to alpha particles from incorporated plutonium.  Conclusion: The established CRS registry providing complete high quality demographical, medical and dosimetry information, together with available biological specimens, in future will allow: the updating of dose–response and dose–time–response relationships; the estimation of latent periods, risks and dose thresholds and associated uncertainties for CRS development; certain tissue reactions in lymphoid and haematopoietic tissues; and a better understanding of their development patterns and mechanisms, taking into account non-radiation factors.