Biological dose estimation for two severely exposed patients in a radiation accident in Shandong Jining, China, in 2004

To estimate the biological doses for two severely exposed subjects (A and B) in a radiation accident in Shandong Jining, China in 2004.Conventional chromosome aberration analysis and cytokinesis-block micronuclei (CBMN) assay were performed in peripheral blood and bone marrow samples on two subjects after the accident. A new dose-effect curve and the nuclear division index (NDI) obtained from in vitro irradiation experiments using high dose of (60)Co gamma-rays were used to estimate the exposed doses.No metaphases or binucleated cells were observed in the peripheral blood cultures from either of the subjects. However, metaphases and binucleated cells were obtained from both subjects after bone marrow cultures. Both dicentric/ring and micronuclei yields were very high. The dose estimated for A and B were 20.0 Gy and 8.8 Gy, respectively, by dicentric/ring scoring, similar to the data by combination of the CBMN and NDI (CBMN + NDI) assay. The estimated doses by the two methods were in accordance with the clinical symptoms.The new curve, together with the CBMN + NDI assay, are reliable for estimating higher doses of irradiation. In future radiation accidents, the accuracy and significance of these methods can be further tested.