Objective To investigate the chromosomal aberrations in seven medical staffs suspected with exposure to ionizing radiation and to speculate its possible causation.Methods The hospital staffs,including 6 females and 1 male,worked in a clinical laboratory where a CT room was located downstairs.The thickness of precast slab between these two rooms was 6 cm.Peripheral blood lymphocytes of seven staffs were examined for conventional chromosomal aberrations.Results The frequencies of dicentrics in the peripheral lymphocytes of 4 females were from 0.40％ to 1.60％ that was significantly higher than the spontaneous frequency of dicentrics (0.03％,x2 =36.79,P ＜ 0.05).The translocation was observed in the lymphocytes from all subjects with frequencies from 0.33％ to 1.20％,obviously higher than its spontaneous frequency of 0.01％ (x2 =42.90,P ＜ 0.05).Conclusion These staffs suffer from ionizing radiation.

Objective:To explore the feasibility of using a High-Throughput Chromosome Automatic Scanning System (Metafer 4) to carry out automatic micronucleus detection for radiation workers.Methods:A total of 2 005 radiation workers selected were divided into five groups in terms of diagnostic radiology, radiotherapy, nuclear medicine, interventional radiology and industrial application.The Metafer 4 was used to assay micronuclei in peripheral blood lymphocytes from the subjects, with the factors affecting micronuclei analyzed. A total of 200 micronucleus samples collected by stratified random sampling were manually assayed for comparison of micronuclei frequency and detection efficiency between automatic and manual analysis.Results:The mean micronuclei frequency in 2 005 radiation workers were measured to be (0.92±0.02) ×10 -3. There was significant difference in the frequencies of micronuclei among the five groups ( χ2=11.054, P<0.05), with higher micronuclei frequency in interventional radiology group(1.00±0.03) ×10 -3 than in other groups ( χ2=5.568, 5.334, 7.689, P<0.05). Statistically significant difference could be observed in annual effective dose, length of service and micronuclei frequency among the radiation workers in different medical applications ( F=3.026, χ2=11.582, 8.878, P<0.05). A positive correlation between annual effective dose and micronucleus frequency was shown by Pearson analysis ( r=0.106, P<0.05). Multiple linear regression analysis showed that the automatic assay-based micronuclei frequencies were associated with length of service and work categories( r=9.485×10 -6, 5.660×10 -5, P<0.05), significantly lower when compared with manual analysis ( χ2=169.259, P<0.05). There was a consistency (ICC=0.713, P<0.05) between the two assay methods, but automatic analysis can increase the assayed micronucleus frequency by about 5 folds. Conclusions:The micronucleus frequency tested by automatic detection reflects genetic damage from low-dose chronic radiation exposure, and there may be feasibility of using automatic analysis to assay micronucleus of radiation workers.

Objective:To investigate chromosomal aberrations in peripheral blood lymphocytes of underground miners, in order to explore the influencing factors involved in chromosomal aberration levels of non-uranium metal mines.Methods:Totall 135 workers were recruited from an iron mine and a gold mine located in different cities of Henan province, where 69 workers worked aboveground and 66 miners worked underground in the metal mines. The radon concentration in the mines was measured by solid-state nuclear track detectors. Chromosomal aberrations in peripheral blood lymphocytes from the subjects were detected using conventional analysis method, and the influence factors of chromosomal aberrations were analyzed.Results:Radon concentration was 30-2 943 Bq/m 3 in the aboveground workplace of the mines, and 62-28 314 Bq/m 3 in underground. The age of the underground group was obviously lower than that of the aboveground group( t=2.12, P<0.05), but the frequencies of dicentrics, translocation, acentric fragment, and total chromosome-type aberrations in the underground group were significantly higher than those in the aboveground group ( χ2=10.49, 16.74, 8.15, 29.50, P<0.01). Consistent results were obtained when only male workers were regarded as object of observation ( χ2=8.44, 11.63, 4.94, 20.81, P<0.05). The frequency of translocation ( χ2=8.44, P<0.05) was dependent on the length of service in the underground group. Poisson regression analysis indicated that the aboveground and undergroud grouping partly affected the levels of dicentrics, translocation, acentric fragment, and total chromosome-type aberrations (the underground group IRR=3.25, 2.69, 1.97, 2.18, P<0.05). Conclusions:The radon exposure in the underground workplace of the metal mines may be the main factor resulting in the increase of chromosome-type aberrations of miners. The occupational health and safety of the miners who may be exposed to high radon levels are worthy of great attention.