Determination of dose-response relationship in cultured human lymphocytes for biological dosimetry

A pplication of the lymphocyte-dicentric assay for biological dosimetry has made significant contributions in both accidental and occupational overexposures and this method plays an important role in diagnosis and prognosis of overexposed individuals (Voisin et al. 2001). By this assay, the frequency of unstable chromosomal aberrations (dicentric and centric ring) in lymphocyte is used to estimate radiation doses received by individuals (IAEA 1986, 2001). The advantages of dicentric assay have made this biological dosimeter the most generally accepted method for dose estimation. This biological dosimeter is the most comprehensively investigated system (Muller and Streffer 1991). Dicentrics are considered relatively radiation specific; only a few chemicals are known to interfere with this assay. Low background levels (about 1 dicentric in 2000 cells), high sensitivity (a threshold dose of 0.05 Gy), and known dose dependency up to 4Gy (for low-LET radiation) make this assay quite robust (Greenstock and Trivedi 1994). Effects of radiation quality and dose rate are also well characterised (Edwards 1997). The influence of the interval between radiation exposure and analysis for a broad dose range is not critical for, at least, the first 2 weeks after exposure (IAEA 2001). Published reports show that differences exist in the measured yield of dicentrics per Gy among several laboratories (Lloyd 1987), and evaluation of dose using a calibration curve, produced by another laboratory may introduce ABSTRACT