Threshold limits for biological indication of prolonged radiation exposure using mFISH.

Chromosome aberration (translocation) yield was investigated by mFISH in peripheral blood lymphocytes of Mayak Production Association (PA) workers with prolonged occupational exposure to ionizing radiation (IR). A dose threshold for cytogenetic indication of a prolonged occupational radiation exposure was estimated for Mayak PA workers using functions of dose distributions. Two limits were estimated for the indication of IR exposure to workers with a prolonged external gamma-ray exposure: These are a background translocation yield of N₀ = 0.812 ± 0.149% and a dose threshold of indication D₀ estimated to be approximately 1 Gy.