Individual dose monitoring and registry for radiation workers plays a significant role in ionizing radiation protection and occupational health management. Since the nationwide implementation of monitoring from the 1980s, individual dose monitoring for radiation workers in China has been going on nearly 30 years, which is of significance in radiation protection optimization, and occupational health and protection for radiation workers. In order to improve individual dose monitoring and registry, to prevent and control occupational radiation diseases, and to help build "Healthy China" program, this paper presents the evolution of individual dose monitoring and registry in China, discusses the key points and difficulties faced, and proposes suggestions.

The Fukushima nuclear accident happened in 2011.This article introduced the recent studies about thyroid dose estimation,incidence of thyroid nodule,thyroid cyst and thyroid cancer in the children in Fukushima prefecture after the accident.The results suggested that the incidence of thyroid nodule and thyroid cyst had no significant increase.Nevertheless,the present research noted that the incidence of thyroid cancer was obviously higher than that in other areas in Japan,but high incidence may be due to the choice of the control group or the screening effect.Meanwhile,the contribution of 132Te to the thyroid dose and the incidence of thyroid cancer might not be ignored.The continuous monitoring before and after the operation of the nuclear power plant and the health evaculation after the accident are of importance.

Objective To introduce the general international method for estimation of lifetime risk of developed cancer,and to estimate the lifetime risk baseline values of several kinds of cancers related to radiation exposures in China.Methods The risk estimation was based on the data from Chinese Cancer Registry Annual Report (2010) and China Population & Employment Statistics Yearbook (2009),and made according to the method previously published by National Cancer Institute (NCI) in USA.Results The lifetime risk of all cancer in China in 2007 was estimated to be 27.77％,that of lung cancer 5.96％,that of breast cancer for female 3.34％,that of all leukemia 0.14％,that of thyroid cancer 0.37％.The lifetime risks of all cancer were estimated to be 32.74％ for males and 24.73％ for females,and that was 36.47％ for urban residents and 26.79％ for rural people.Conclusions The lifetime risk of all cancer for males in 2007 was about 1.25 times as much as that for females.The value of all cancer for urban residents was about 1.35 times as much as that for rural residents.The lifetime risk of developed cancers in 2007 in China is lower than that in the developed countries,such as Japan.

Objective To provide the dose information from the epidemiological cohort established in 1980 in Jiangsu province using normalized workload method,and to estimate cumulative skin dose to medical diagnostic X-ray workers based on personal dosimeter were worn as members of the epidemiologicat cohort.Methods Data for fixed cohort members of X-ray exposure history from 1950 to June 2011 were collected.According to correction factors such as examination types and protection conditions,exposure doses from 1950s to June of 2011 were estimated through a Visual Basic language program.Results Average annual doses vary significantly between during different time periods:10.1 (6.1-12.3) mGy/year during 1950-1965,3.5 (2.1-5.4) mGy/year for 1966-1984 and 1.3 (0.9-1.9) mGy/year during 1985-2011,respectively.Conclusions Average annual doses received by 3 961 medical diagnostic X-ray workers during different time periods in this investigation are nearly consistent with the results reported previously and show a roughly similar trend.

Objective:To ascertain the levels of individual doses to radiation workers arising from occupationally external exposure in China in 2017, with an aim to provide basic data and scientific basis for prevention and control of occupational radiation sickness.Methods:Data on individual doses to monitored workers engaged in medical and industrial applications of radiation sources were collected through National Individual Dose Registry, with statistical analysis being carried out using Kruskal-Wallis H test, Mann-Whitney U test and Bonferroni method. Results:A total of 361 727 radiation workers were investigated in 2017, of which 81.6% was from medical application and 18.4% from industrial application, respectively. The average annual effective dose from medical and industrial applications were 0.353 and 0.270 mSv, respectively, with the former significantly higher than the latter ( Z=48.547, P<0.05). Furthermore, a statistically significant difference was seen in the average annual effective dose for each occupational category of medical application ( H=1 136.217, P<0.05), suggesting that the dose values for the monitored workers in nuclear medicine and interventional radiology were significantly higher than for other four medical categories ( Z=2.877-26.967, P<0.05). These dose values for the radiation workers was 0.361 mSv in tertiary hospitals, 0.397 mSv in secondary hospitals, and 0.308 mSv in primary and unrated hospitals, respectively. The dose values for the monitored workers in industrial radiography and well logging were significantly higher than for other five industrial categories of industrial applications ( Z=4.172-36.908, P<0.05). Conclusions:The average annual effective doses to the of monitored workers meet the relevant national standards. The exposure doses to the workers in nuclear medicine, interventional radiology, industrial radiography and well logging are relatively high. The necessary measures and devices for radiation protection should be further strengthened to reduce occupational exposure of workers.

Objective:To investigate the levels of dose to eye lens of interventional radiology workers in China from 2017 to 2019.Methods:The monitoring data on eye lens doses to the interventional radiology workers in 28 provinces across the country were collected from National Individual Dose Registry. Monitoring was carried out using TLDs on their left eyes and evaluated in terms of the personal dose equivalent Hp(3). By using Mann-Whitney U test and Kruskal-Wallis H test, statistical analyses were made of the average annual lens doses to interventional radiology workers in the hospitals of different types at different levels for different years. Results:From 2017 to 2019, the data on eye lens doses to 2 981 interventional radiology workers were collected, with doses ranging from below the minimum detectable level (MDL) to 64.48 mSv, the average annual eye dose of 1.38 mSv, and the annual doses incurred by 0.97% monitored workers exceeding the recently recommended dose limits, 20 mSv per year. The average annual lens dose monitored in general hospitals and in cancer hospitals were 1.33 and 1.77 mSv, respectively, without statistically significant difference ( P>0.05). The average annual lens dose in tertiary hospitals was 1.39 mSv, significantly higher than that in secondary hospitals where the value was 1.16 mSv ( Z=2.894, P<0.05). Conclusions:The estimated annual eye lens doses to the interventional radiology workers during 2017-2019 were in accordance with the current national standard GB 18871-2002, but with a few exceptions exceeding the current international standards. This means that there exists, to a certain degree, a potential risk for the eye lens in this work category to exceed the international limits. It is suggested to continue in effort to enhance the monitoring of eye lens dose for these workers and to increase risk awareness, and take effective protective measures so as to lower the level of eye lens doses.

Objective:To analyze the dose range distribution of abnormal result, the distribution of occupational categories, the incidence of abnormal result of different occupational categories, the causes of abnormal result and the factors influencing abnormal values, on the basis of investigated abnormal result of individual monitoring for occupationally external exposure, in order to provide the scientific basis for the formulation of the relevant regulations and standards and the hospital radiation protection management.Methods:The abnormal result of 389 radiation workers in medical institutions receiving annual individual doses each exceeding 1.25 mSv, reported in 2017 in 19 provinces, were collected and analyzed.Results:Dose distribution range of abnormal result were mainly between 1.25 and 5 mSv; diagnostic radiology workers accounted for the highest fraction, 59.64% of the totals; and interventional radiology workers had the highest incidence, 4.17‰ of abnormal result. The abnormal result was mainly caused by improper wearing or operating personal dosimeters; the abnormal values in the eastern regions were higher than those in other regions, with a median of 6.41 mSv; the abnormal values in the cause-unknown group was higher than those in other groups, with a median of 10.32 mSv.Conclusions:The publicity and training of radiation protection knowledge should be further strengthened to improve the protection awareness of radiation workers. The occupational exposure of interventional radiology workers should receive special attention.

Objective To increase externally-assigned response, improve energy response of CR39 and develop positive fast/thermal neutron personal dosimeter applicable for occupational exposure in oil and gas field logging by using pre-recoil layer.Methods The externally-assigned response of CR39 detector was improved through increasing the track density by using the α particle induced by the reaction of 10B(n,α) 7Li with the BN as pre-recoil layer, and the increase was vilified by using both Monte-Carlo simulation and experiment exposed by standard neutron source.Results Fast/thermal neutron personal dosimeter's neutron flux sensitivity and neutron dose equivalent sensitivity were 3.46 × 10-4 track per 0.013 and 52.8 mSv.According to theoretical derivation and experiment of standard 241 Am-Be neutron source, detecting efficiency and energy response of CR39 were effectively improved, and quantitative measurement of dose contributed by thermal neutron was realized.Conclusions CR39 fast/thermal neutron personal dosimeter of high sensitivity is applicable to oil and gas field logging environment and of potential development.

Objective To explore whether low-dose occupational ionizing radiation exposure can affect the prevalence of lens opacity.Methods Annual occupational health checkup data of 1 007 radiation workers was taken from a provincial medical institution for the purpose of statistical analysis.Logistic regression analysis was used to estimate occupational exposure odds ratios (OR) of lens opacity,adjusted for age,gender and length of service.Eye lens opacity was grouped into cortical,nuclear and posterior subcapsular opacity according to the position of the opacity occurrence site.Opacity occurred in any one of the both eye lens was recorded as turbidity.Results Only 730 cases coupled with complete information could be used in the statistical analysis.The rate of lens opacity for all the radiation workers was 10.27％.The rates of lens opacity by exposure group were estimated to be 9.07％ for radiation diagnosis and therapy group,11.11％ for intervention group,18.18％ for nuclear medicine group,and 9.33％ for industrial application group,respectively.Compared with those in the radiation diagnosis and therapy group,the workers engaged in intervention medicine,or nuclear medicine,were more likely to suffer from the lens opacity in posterior subcapsular position.The OR and its 95％ confidence intervals were 3.00 (1.23-7.33),4.12 (1.68-10.11) for the workers in intervention medicine or nuclear medicine group.Conclusions Medical radiation workers,who were exposed to long-term low-dose of ionizing radiation,especially those who engaged in intervention or nuclear medicine,were at significantly higher risk to develop lens opacity.

Purpose To develop a national registry and reporting system of individual monitoring for workers occupationally exposed to ionizing radiation.Methods In accordance with the relevant law,regulations,standards and the current health supervision practice for radiation workers in China,to ensure more effective collection of information on individual monitoring from all levels of service providers across the country and an easy query and analysis of the collected information for both service providers and administrative institutions,the register consisted of an offline-system and a web-based information system.The off-line system consisted of 8 tables,which could easily make annual and period monitoring reports,and upload individual monitoring data in compressed and encrypted format.Web-based system consisted of 6 modules,could easily make S customized tabulations of monitoring data and show 2 trend figures.SSLVPN secure remote access was used in the system.Arranged by the Ministry of Health,training courses provided to all individual monitoring service providers and provincial administrative institutions.Results A new and individual-based national register and reporting system of individual monitoring for workers occupationally exposed to ionizing radiation was successfully developed,and would be officially run soon.Conclusions The establishment and running of the register would be great improvement on the national radiological health reports and produce a far-reaching impact on the individual monitoring in China.