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Background The thyroid gland is one of the organs sensitive to ionizing radiation, and there are few studies on the effects of long-term exposure to low doses of ionizing radiation on the thyroid gland of radiation workers. Objective To investigate thyroid abnormalities in workers in medical radiology departments in Guangdong Province and to identify potential influencing factors of thyroid abnormalities. Methods A total of 1657 radiation workers from 48 hospitals in Guangdong Province were selected as survey subjects using convenience sampling, and their personal dose monitoring results and health examination information were retrospectively analyzed to determine the factors affecting thyroid abnormalities. Results The M (P25, P75) of thyroid absorbed dose (DT) was 1.55 (0.65, 3.96) mGy in the 1657 investigated workers. The attribute-specific medians of DT were 1.29, 1.38, 1.99, and 3.51 mGy for departments of diagnostic radiology, interventional radiology, radiotherapy, and nuclear medicine, respectively; and 1.10, 1.55, and 1.80 mGy for job titles of nurse, technician, and physician, respectively. Differences in DT by gender, age, years of radiological work, age of radiation exposure onset, occupational category, and job title were statistically significant (Z=−6.35, H=708.52, 918.20, 31.19, 95.64, 39.28, P<0.05). The positive rate of thyroid abnormalities in investigated workers was 46.53% (771/1657). Among them, the positive rate of abnormal thyroid function was 22.87% (379/1657), that of abnormal thyroid morphology was 33.98% (563/1657), and that of thyroid nodule was 26.55% (440/1657). The differences in thyroid abnormality rates by gender, age, years of radiation work, age of radiation exposure onset, DT, and job title of radiation workers were statistically significant (χ2=51.89, 49.64, 20.54, 18.29, 12.07, 16.16, P<0.05). The differences in abnormal thyroid function positive rate by gender, age of radiation exposure onset, and job title were statistically significant (χ2=26.21, 6.21, 8.32, P<0.05). The differences in the positive rates of abnormal thyroid morphology and nodules were statistically significant by gender, age, years of radiological work, age of radiation exposure onset, DT, and job title (abnormal thyroid morphology, χ2=40.24, 64.17, 37.63, 15.17, 19.28, 15.05; nodules, χ2=31.41, 77.98, 42.11, 19.16, 21.70, 13.52, P<0.05). The positive rates of thyroid abnormality, thyroid morphology abnormality, and nodules all showed a linear increasing trend with increasing age, years of radiation work, and age of radiation exposure onset (P<0.05). The results of logistic regression analysis indicated that the factors influencing thyroid abnormalities were female (OR=2.17, 95%CI: 1.72-2.74), increased years of radiological work (OR=1.04, 95%CI: 1.03-1.06), onset of radiation exposure in age groups of 30-34 and ≥35 years (OR=1.63, 95%CI: 1.12-2.37; OR=2.58, 95%CI: 1.74-3.29), and working in department of diagnostic radiology (OR=1.40, 95%CI: 1.07-1.84). Conclusion Long-term exposure to low doses of ionizing radiation has an effect on thyroid abnormalities in medical radiation workers. Among them, being female, physicians, and working in department of diagnostic radiology are at a higher risk of abnormal thyroid function; being female, increased years of radiation work, and radiation exposure onset at age ≥30 years are associated with a higher risk of reporting abnormal thyroid morphology.
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Objective:To investigate the exposure level of ionizing radiation in medical radiation workers in Guangdong province, as well as their abnormality in the lens of the eye, and to analyze associated influence factors.Methods:In this study, 1 501 radiation workers from 60 hospitals were selected by using convenient sampling method for retrospecotive analysis of absorbed doses ( DL) to the lens of the eye, health examination information and the relevant influence factors. Results:The median value M and the 25 th and 75 th percentile values ( P25, P75)of the distribution of absorbed doses were 4.86, 2.99 and 7.90 mGy, respectively. The median values for male and female were 5.14 and 3.94 mGy, respectively. The median values for the Levels I, Ⅱ and Ⅲ medical institutions were 2.95, 3.51 and 5.06 mGy, respectively. The median values were radiotherapy 4.05 mGy, radiodiagnosis 4.84 mGy, interventional radiology 5.39 mGy and nuclear medicine 6.71 mGy, as well as nurses 3.48 mGy, physicians 5.03 mGy and technologists 5.03 mGy, respectively. There were statistically significant differences in dose distribution for different gender, age, length of radiation service, age at the beginning of radiation exposure, level of medical institution, occupational category and post ( Z=-6.72, H=389.64, 511.17, 70.29, 53.29, 49.06, 39.89, P<0.05). The detectable rate for increased cortical density of lens was 22.45% (337/1 501) and for lens turbidity was 8.19% (123/1 501). The detectable rate of increased cortical density showed a linear increasing trend with the increase in age, age of radiation service, age at the beginning of exposure to radiation, level of medical institution and dose ( χ2=366.36, 313.77, 15.18, 21.61, 92.13, P<0.05). The detectable rate of lens opacity increased linearly with the increase in age, length of radiation service, level of medical institution and dose( χ2=69.64, 67.65, 67.65, 37.37, P<0.05), and decreased linearly with the increase in age at the beginning of radiation exposure ( χ2=4.25, P<0.05). Logistic regression analysis showed that age was the influencing factor of increased cortical density ( χ2=165.98, P<0.05), and the risk of cortical densification increased with age ( OR=1.33, 95% CI: 1.27-1.39). Age, length of radiation service and occupation were the influencing factors of lens opacity ( χ2=25.78, 4.99, 6.88, P<0.05). The risk of lens opacity increased with age ( OR=1.17, 95% CI: 1.10-1.24). The risk of lens opacity increased with age of radiation service ( OR=1.06, 95% CI: 1.01-1.12). The risk of ocular opacity was higher in interventional radiology than that in diagnostic radiology, radiotherapy and nuclear medicine ( OR=2.59, 95% CI: 1.27-5.25). Conclusions:Long-term exposure to low dose ionizing radiation has a certain correlation with the abnormal lens detectable rate of medical radiation workers. Age, length of radiation service and occupation are the influencing factors of lens opacity.
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Objective:To explore the investigation level of individual monitoring for medical radiation workers.Methods:Monitoring and analysis of individual doses to the medical radiation workers in Guangdong province were performed, from 2016 to 2019, by the Individual Dose Monitoring Department of Guangdong Provincial Hospital for Occupational Disease Prevention and Control.Results:The numbers of monitored workers were diagnostic radiology 53 674, dental radiology 2 563, nuclear medicine 5 001, radiotherapy 16 687, interventional radiology 22 272 and others 2 087 from 2016 to 2019, of which the number of individuals with doses in excess of investigation level 1.25 mSv, were 76, 6, 18, 28, 133 and 2 respectively. The non-real doses made up 67.1 %, 100 %, 55.6 %, 82.1 %, 76.7 % and 100 % of their respective totals. Their 99th percentile doses P99 were 0.37, 0.39, 0.67, 0.35, 0.54 and 0.30 mSv, and the average periodic dose equivalent were 0.07, 0.06, 0.11, 0.06, 0.07 and 0.05 mSv respectively, indicating a statistically significant difference existing in the average annual effective dose between groups ( Z=-26.139--2.681, P<0.001). Conclusions:Due to non-reality of doses in excess of investigation levels and high labor cost, it is suggested to currently use 0.40 mSv per 3 months as investigation level for diagnostic radiology, dental radiology, radiotherapy and others, and 0.70 mSv per 3 months as for nuclear medicine and interventional radiology.
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OBJECTIVE: To analyze the growth arrest and DNA damage gene 45( GADD45) mRNA expression in peripheral blood of radiation workers,and its relationship with exposure dose. METHODS: Using a typical sampling method,97 radiation workers from a hospital of Guangdong were selected as radiation group,48 hospital administrative staff without exposure to radiation and other occupational hazard factors were selected as control group. The real-time quantitative polymerase chain reaction was used to detect GADD45 mRNA expression of two groups. With the use of thermoluminescence dosimetry,we detected and collected personal dose data of radiation group over the past year. RESULTS: The GADD45 mRNA relative expression of the radiation group was higher than that of the control group( P < 0. 01).There was no correlation between GADD45 mRNA relative expression and factors such as personal dose,sex,age,length of service,smoking,and alcohol drinking( P > 0. 05). CONCLUSION: The ionizing radiation can lead to up-regulation of GADD45 mRNA expression in peripheral blood of radiation workers,but there was no linear relationship between GADD45 mRNA expression and its personal dose.