The effect of the beta-emitting yttrium-90 citrate on the dose-response of dicentric chromosomes in human lymphocytes:a basis for biological dosimetry after radiosynoviorthesis

摘要

The production of dicentric chromosomes in human lymphocytes by beta-particles of yttrium-90 (Y-90) was studied in vitro to provide a basis of biological dosimetry after radiosynoviorthesis (RSO) of persistent synovitis by intra-articular administration of yttrium-90 citrate colloid.Since the injected colloid may leak into the lymphatic drainage exposing other parts of the body to radiation,the measurement of biological damage induced by beta-particles of Y-90 is important for the assessment of radiation risk to the patients.A linear dose-response relationship (alpha=0.0229+-0.0028 dicentric chromosomes per cell per gray) was found over the dose range of 0.2176-2.176 Gy.The absorbed doses were calculated for exposure of blood samples to Y-90 activities from 40 to 400 kBq using both Monte Carlo simulation and an analytical model.The maximum low-dose RBE,the RBE_M which is equivalent to the ratio of the alpha coefficients of the dose-response curves,is well in line with published results obtained earlier for irradiation of blood of the same donor with heavily filtered 220 kV X-rays (3.35 mm copper),but half of the RBE_M relative to weakly filtered 220 kV X-rays.Therefore,it can be concluded that for estimating an absorbed dose during RSO by the technique of biological dosimetry,in vitro and in vivo data for the same radiation quality are necessary.