Analysis of abnormal dose values from individual dose monitoring for radiation workers in medical institutions in China in 2020 / 中华放射医学与防护杂志

Objective:To analyze distributions of dose range, occupational category, and causes of abnormal dose values from individual dose monitoring of radiation workers and to provide recommendations for improving the quality of individual monitoring data and occupational health management in medical institutions.Methods:The data of individual dose monitoring result exceeding 1.25 mSv in a single monitoring cycle, collected by Occupational Health System for Radiology Facilities’ on National Radiological Health Information Platform, was analyzed.Results:A total of 1 113 abnormal dose values were detected in 31 provinces in 2020, with an abnormal rate of 2.48‰, of which workers of diagnostic radiology and interventional radiology accounted for 68.01% and 18.78%, respectively. The dose distribution of abnormal dose values was mainly between 1.25 and 5 mSv. The abnormal dose values were mainly caused by improperly wearing or using personal dosimeters, accounting for 63.88%. Workers for whom the dose values was abnormal due to increased workload accounted for 12.32%, with an average annual individual dose of 5.14 mSv. There was no statistically significant difference in annual individual dose among radiation workers between different occupational groups( P>0.05). Conclusions:Education and training on radiation protection for radiation workers should be strengthened, and a specific and feasible system for radiation protection management, as well as a reward and punishment system, should be established in order to reduce the occurance of the improper wearing of personal dosimeters. Great attention should be paid to occupational exposure of workers in diagnostic radiology and interventional radiology, and a work shift system should be conducted to reduce individual dose levels. It is recommended that standard verification procedures for abnormal dose values from individual dose monitoring should be developed to improve the quality of individual monitoring data.

Standard interpretation of radiological protection requirements for the production places of rare earths / 中国辐射卫生

Chinese national standard GBZ139—2019 Radiological Protection Requirements for the Production Places of Rare Earths was published to replace GBZ 139—2002 Radiological Protection standards for the production places of rare-earth elements and implemented from April 1, 2020. Herein, background on which the new standard was based, the main modifications and the foundations were explained. More specific requirements for the production places of rare earths were stipulated in the new standard, which will play an important role in occupational health protection of the workers engaged in the mining, mineral processing and smelting of rare earths.

Analysis of occupational radiation sicknesses diagnosed in China from 2013 to 2017 / 中华放射医学与防护杂志

Objective To analyze the changes in distribution of occupational radiation cases reported from 2013 to 2017 in China and learn about the occupational health risks of radiation workers.Methods Descriptive analyses were made of regional distribution,disease category distribution,occupation category distribution and exposure mode distribution of these cases,according to the reports (2013-2017) of occupational radiation sickness from " Occupational Health of Radiation Workers Management System".Results There were 54 diagnostic radiology agencies for occupational radiation sickness in China that covered all provinces,autonomous regions and municipalities except Tibet and Production and Construction Corps of Xinjiang.A total of 106 new cases were reported from 2013 to 2017.Most of the cases were radiogenic neoplasm (43.40％),and chronic radiation sickness were from external exposure (16.98％) and radiation cataract (16.04％).Most of the cases (70.75％) were engaged in medical application and a small part of the cases (13.21％) engaged in industry application.Chronic exposure (80.19％) was the most frequent form of exposure mode,but acute exposure (5.66％) was very few.A part of cases (14.15％) were reported without exposure mode.Conclusions The morbidity of occupational radiation sickness declined generally in China and occupational health management of key workers should be strengthened continuously.

Study on cardio-ankle vascular index among female residents in high radiation background area in Yangjiang City / 中国职业医学

OBJECTIVE: To explore the effect of long-term low-dose ionizing radiation exposure on arterial vascular elasticity in female residents. METHODS: A cluster random sampling method was used,95 female residents in 2 regions with high external γ radiation dose rate in the high radiation background area( HBRA) in Yangjiang City were selected as the HBRA group,and 96 female residents from the control area( CA) in Enping City were chosen as the CA group. The height,body mass,waist circumference,hip circumference and blood pressure were measured in individuals of these two groups. The fasting blood samples of elbow vein were collected to measure high-density lipoprotein cholesterol( HDL-C),low-density lipoprotein cholesterol( LDL-C),triglycerides( TG) and blood glucose. The cardio-ankle vascular index( CAVI) was measured using the blood pressure and pulse check device. RESULTS: The CAVI of the CA and HBRA groups were( 8. 09 ±1. 03) and( 8. 35 ± 1. 60) m/s,respectively. The abnormal rates of CAVI were 25. 00% and 29. 47%,respectively. The results of multiple linear regression analysis showed that after adjustment for age,HDL-C,LDL-C,TG,hypertension,abnormal glucose metabolism and abdominal obesity,the CAVI adjustment mean values of the CA and HBRA groups were8. 19 and 8. 25 m/s,respectively. The HBRA group was about 0. 73% higher than the CA group,but the difference was not statistically significant( standardized partial regression coefficient = 0. 021,P > 0. 05). After matching age of both groups,the difference of the adjusted mean of CAVI between the two groups was not statistically significant( P > 0. 05).CONCLUSION: Long-term low-dose radiation exposure is not associated with atherosclerosis in female population.

Preliminary research on telomere length of residents in high level natural background radiation area Yangjiang of China / 中华放射医学与防护杂志

Objective To explore the effect of long-term low dose ionizing radiation on telomere length in adults. Methods Forty female residents aged more than 55 years old from high level natural background radiation area in Yangjiang city and forty age-matched female residents from control area in Enping city were selected by quota sampling as high background group and control group, respectively. Genomic DNA was isolated from their peripheral blood. Telomere length was determined using real time q-PCR. The t-test was used to compare the square roots of the means of two groups. The individuals were divided into four groups based on ages ( 55 -, 60 -, 65 - and ≥70 ) and four groups based on BMI ( <18. 5, 18. 5-23. 99, 24. 0 -27. 99 and ≥28. 0). After adjusting age and BMI, multivariate linear regression analysis was performed to study the relationship between telomere length and cumulative exposure dose. The individuals were divided into longer telomere length group (≥2 ) and shorter telomere length group ( <2). Logistic regression analysis was performed to study the relationship between telomere length and cumulative exposure dose. Results The average cumulative dose was(169. 52 ± 27. 43)mSv for high background group and(47. 52 ± 6. 50)mSv for control group. The telomere length of high background group was( 1. 98 ± 1. 25 ) , shorter than that of control group ( 2. 69 ± 1. 44 ) with statis-tically significant difference(t=2. 24, P <0. 05). The multivariate linear regression analysis revealed that the effect of cumulative dose on telomere length was not significant ( P>0. 05 ) . Association between telomere length and cumulative dose was explored through Logistic regression, and odds ratio was taken as 0. 992(95% CI, 0. 985-0. 999 ) . There was a weak inverse association between telomere length and cumulative dose, because the odds ratio ( OR) was very close to 1. Conclusions No obvious dose-effect relationship between telomere length of residents and cumulative radiation doses was found. But the long-term low dose ionizing radiation may lead to the shortening of the telomere length in adults.

A study on cancer mortality of the residents in the high background radiation area in Yangjiang,China (1979-2002) / 中华放射医学与防护杂志

Objective To increase the statistic power to estimate radiation-induced cancer risk on the basis of analysis of the 1999-2002 follow-up data from high background radiation areas (HBRA), in combination with those in the period 1979-1998, and further to estimate radiation-induced cancer risk at low dose after adjustment of individual smoking factor.Methods Cohort studies were conducted of cancer mortality for the residents in both HBRA and control area (CA), with follow-up made in phases.The present study was first focused on the collection of cancer mortality data during 1999-2002, with preliminary analysis of the risks of cancer mortality.And then, the effort was dedicated to analysis of both the risks of cancer mortality and the smoker-adjusted risks of radiation-induced cancer mortality from for the residents in HBRA in period 1999-2002 based on the pooled data during 1999-2002 and 1979-1998 through ID record linkage.Person-years were estimated using Epicure/DATAB model.The relative risk (RR), the excess relative risk coefficient (ERR/Sv) and confidence interval (CI) of cancer mortality from 1979 to 2002 were estimated using Poisson regress model in AMFIT mode.Results A total of 76 264 persons in HBRA and CA was followed up during 1999-2002, covering 300 523 person-years and 2 267 deaths identified, including 239 cancer deaths.Based on pooled data, 125 079 persons were followed up during 1979-2002, which covered 2 293 463 person-years and 14 711 deaths identified, including 1 441 died of cancer.The sex-and age-adjusted RR of all cancers in the HBRA during 1979-2002 was 0.99 (95％ CI: 0.89 to 1.11), showing no statistically significant differences between HBRA and CA (P ＞ 0.05).The value of ERR/Sv of all cancer mortality during 1979-2002 was-0.01 (95％ CI:-0.50 to 0.64).Smoker-adjusted RR of all cancer mortality in HBRA during 1987-2002 was 1.00 (95％ CI:0.87 to 1.15), with no statistically significant difference (P ＞ 0.05).The value of ERR/Sv for all cancers during 1987-2002 was 0.01 (95％ CI:-0.56 to 0.81) after adjustment of smoking.Conclusions Increased risk was not found in relation to radiation exposure at low dose in HBRA.After adjustment of smoking, the statistical difference has not been shown in all cancer mortality between HBRA and CA, but excess relative risk increased slightly.

Survey on basic data of risk estimation of lung cancer among non-uranium miners in China / 中华放射医学与防护杂志

Objective To investigate the basic data of risk estimation of lung cancer among non-uranium miners in China.Methods 2836 workers from 24 mines in 9 provinces/regions were face-to-face interviewed to collect information including age at exposure,exposure duration,cigarette smoking among others.Results Age of the investigated non-uranium miners ranged from 17 to 72(36.9±8.0)years.The miners received low and poor education,3% of them were illiterate,58% with primary and middle school education,only 7% with junior college and higher education.Seventy-five percent of the uranium miners are migrant rural workers.Ethnic minority miners accoungted for 16% of all the investigated miners.Among the migrant rural workers age at initial exposure was estimated to be 29.6±8.0 years.By the time of the investigation,46.7% of the miners had worked in the mine for five years and longer,working years in the mine was 6.7±6.8 years with a median of 4.1years.3.4% of the non-uranium miners began the initial radon exposure in mines before their 18 years of old.17.5% of the investigated miners reported working more than 8 h every working day.Among the males,58.0% were current smokers with a median of 16 cigarettes per day.Age to begin the cigarette smoking was 20 years on average.Current smoking rate was age-dependent,the rate as high as 69.2% for the males aged 15-19 years.Current smoking rate was significantly statistically lower in coal mines than that in other mines,49.0% vs 62.5%.Compared with other miners,more frequent mechanical ventilations were reported by coal miners,Conclusions In China non-uranium mines,75% were migrant rural workers,by the time of the investigation about half of them had worked in the mines for at least five years.Non-uranium miners began their mining at 30 years on average,with a very small percentage of 3%,exposed to the mining radon before their 18 years.Current cigarette smoking rate in non-uranium male miners was the same as the general male population in China.