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Objective:To explore whether or not radioactive wastewater leakage or overflow exists in the nuclear medicine decay pool after the 7·20 extraordinary rainstorm disaster and to analyze its causes, so as to provide scientific basis for the design, construction and maintenance of the nuclear medicine decay pool and the radiation protection management of nuclear medicine in the future.Methods:Three hospitals A, B and C where 131I therapy are being performed were selected in Zhengzhou city, Henan province. Sampling points were set based on the monitoring result of the environmental radiation level around the nuclear medical decay pool in line with the relevent standard method. Soil samples were collected at different depths. The 131I radioactivity level in the soil was measured using HPGe gamma spectrometer, with the measured result being processed and analyzed. Results:Except for Hospital B where no 131I was detected, different 131I activity concentrations were detected in the soil samples collected around the nuclear medicine decay pool at Hospitals A and C. The 131I activity concentrations ranged from 16.4 to 98 111.8 Bq/kg at Hospital A and from 10.6 to 7 176.6 Bq/kg at Hospital C. After a time period of decay, the repeated detection has shown that the 131I activity concentrations ranged from 1.3 to 17.0 Bq/kg at Hospital A and from 3.9 to 7.1 Bq/kg at Hospital C. The 131I activity concentration in the soil at the depth of 0-5 cm was higher than that at the depth of 5-10 cm soil at the same sampling point. The ratios of activity concentration of 131I between different depths ranged from 1.3 to 13.1, with the median value of 5.9. Conclusions:After the 7·20 extraordinary rainstorm disaster, the surrounding environment of nuclear medicine decay pools at a few hospitals was contamminated by 131I to some extent. To prevent the risk of leakage of radioactive wastewater, the safety evaluation and management of radiation protection should be made better with increased awareness during the design, evaluation, construction and use of nuclear medicine decay pools.
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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.
ABSTRACT
<p><b>OBJECTIVE</b>To establish a rapid determination method with gas chromatography-mass spectrometer (GC-MS) for thiodiglycolic acid (TDGA), a vinyl chloride (VCM) biomarker.</p><p><b>METHODS</b>A high- sensitivity determination method was established using a moderate methyl esterification instead of methyl esterification of highly toxic diazo reaction.</p><p><b>RESULTS</b>The standard curve regression linear equation of the method was: y=8460.5x-4758.2, the linear coefficient was 0.999 7, the minimum quantity concentration was 2.0 µg/L, the range of precision value was 0.81%-2.38%, and the average recovery of standard addition was 99.0%-102.9%.</p><p><b>CONCLUSION</b>This method reduces the risk of traditional methyl esterification, improves the determination sensitivity compared with the GC-FPD method, and meets the determination requirement of TDGA.</p>