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 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 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 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.

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.

Objective To ascertain the frequency distribution of CT examinations in children.Method A wide range of information was collected through the radiology information system (RIS),including ID,sex,birth date,examination time,the examined part of body and other relevant ones related to children who underwent CT examinations between Jan 1,2012 and Dec 31,2012.The SAS software was used for data processing and statistical analysis.Results A total of 1 542 children underwent 1 670 examinations,of which 67％ were male.Head CT examination was the most frequent,accounting for 71.9％ of all CT examinations,and followed by the abdomen/pelvis examinations.The number of examinations of children undergoing the repetitive examination accounted for 6.4％; 51.7％ of the examinations was for trauma.The positive rate of CT examination was 51％,dependent upon the age and examined body parts to some extent.The younger patients had lower positive rate,and the positive rate of head CT examination was lower than those in other parts.Conclusions To reduce the possible cancer risk to be induced by the ionizing radiation from CT,justification of CT examination should be considered for children.

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.

Objective To investigate the public's perception and attitudes on the development of nuclear power, assess their knowledge about nuclear power and radiation, and to build a database on the public's perception for the purpose of providing better public health service, associate technical support and give suggestions for decision-makers.Methods In total of 1 440 local residents who live within 30 kilometers of a proposed nuclear power were chosen for in-person interviews.Questionnaires comprised of 49 questions designed to assess the public's knowledge of radiation and nuclear power, their attitudes to the development of nuclear power, their evaluation of local government and their informational environment.ANOVA was used to compare the influence of different factors on cognitive level.Multivariate linear regression was used to analyze the main factors affecting the level of public awareness.Comparison among groups (respondents in this survey vs.other comparable surveys) was conducted using x2 test.Results Of the respondents, 29.7％ and 39.5％ of respondents knew about nuclear power and radiation, respectively, 24.2％ supported the construction of a nuclear power plant in their own area, which was lower than the average national support for construction of nuclear power plants (29.0％) (x2 =8.71 ,P ＜ 0.05).When queried about safety cncerns 36.8％ of respondents worried about the safety of nuclear power plant and 78.5％ of respondents were afraid of the damage to their health, while 34.1％ of respondents held the belief that the nuclear power plant could bring harmful effect even under normal operation.Regarding the informational environment, 90.0％ of the respondents could not or barely got access to knowledge on nuclear power plants, 71.1％ hoped to acquire the knowledge on nuclear power plants, 48.4％ hoped to acquire this knowledge by television programs, and 62.4％ mostly trusted information given by experts from universities or institutes.In comparison to other findings acquired in similar surveys on the Tianwan and Qinshan nuclear power plants before the Fukushima accident, the findings indicated that safety assessment of nuclear power plant were lower (x2 =20.49,56.96, P ＜ 0.05).Conclusions The public's knowledge level on nuclear power and radiation directly influenced their attitude on nuclear power.The related agencies should strengthen publicity and education in order to increase the public's knowledge on nuclear power and radiation.The communication platform between the related agencies and the public should be established.Active and continued risk communication should be carried out to increase public acceptance of nuclear power.

Objective To estimate the radiation dose and cancer risk of thyroid for children who underwent head CT or chest CT scans.Methods The parameters used in the CT scans were accessed from the DICOM files through PACS used DCMTK software, then the thyroid radiation dose was estimated with the CT-Expo(C) software and the cancer risk induced by CT scan was projected based on BEIR Ⅱ model combined with the Chinese cancer incidence and lifetime table in 2008.Results CT parameters used for different ages were roughly the same, the thyroid equivalent dose for head CT ranged from 1.2-2.0 mGy, the highest thyroid cancer risk occurs for newborn girls, about 9.6/100 thousand population;while for chest CT the thyroid equivalent dose ranged from 8.1 to 38.0 mGy, the highest thyroid cancer risk was also for newborn girls, about 244.7/100 thousand population.The radiation dose and cancer risk for thyroid decreased with the increased age.Conclusions The radiation dose for thyroid from chest CT was relatively higher than head CT, especially for newborn babies;therefore more protection should be given to the thyroid and other radio-sensitive organs during CT scanning.