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 reduce the radiation dose to children from CT scanning through proper adjustment to milliamps (mAs) and scan lengths with a view to learning the relationship between scanning condition and radiation dose.Methods To compare the differences in main scanning parameters used for head,chest and abdomen at multi-detector CT examination of paediatric patients (＜ 1 year old,1-5 years old,6-10 years old,11-15 years old) at seven hospitals in Jiangsu province.CT dose index (CTDI) and dose-length-product (DLP) were gained by using standard children dose model (diameter 16 cm) under the same scanning conditions.Effective doses (E) at different parts of the body from children CT scanning were estimated after modification by empirical weighting factor.Statistical analyses of mAs,scan lengths and DLP were performed with SPSS 16.0 software.The differences in radiation dose due to the choice of condition of scanning were compared between two typical hospitals.Results The mean values of effective doses to paediatric patients during head,chest and abdomen CT scanning were 2.46,5.69,11.86 mSv,respectively.DLP was correlated positively with mAs and scan length (head,chest and abdomen examination,r =0.81,0.81,0.92,P ＜0.05).Due to higher mAs used,the effective dose from chest and abdomen CT examination among all age groups was higher than that in Germany Galanski research.Due to larger scanning length in abdominal examination among all age groups,effective doses in hospital were the highest.Conclusions Reasonablely reducing the scan length and mAs during CT scanning could lower children's CT radiation risk,while clinical diagnosis is not affected.

Objective To study the relationship between the risk of malignant tumor and occupational radiation factor among medical diagnostic X-ray workers in Jiangsu province.Methods The retrospective and prospective cohort studies were adopted to investigate the incidence of cancer.Eligible medical diagnostic X-ray workers from the department of radiology in hospitals were selected and assigned into exposure group,while other medical workers from the departments of Internal Medicine,Ear-NoseThroat (ENT) or Pediatrics who attended work at the same period in the same hospital but not engaged in radiation work were regarded as control group during 1950-2011 in Jiangsu province.We calculated the total person-year and analyzed the relative risk (RR) of malignant tumor using Poisson regression model.Results 7 703 participants (3 961 in exposed group and 3 742 in unexposed group) were recruited and followed up,with a total of 315 309 person years and the lost follow-up rate was 6.92％ (533/7 703).During the follow up period,a total of 819 tumor cases were identified (771 were malignant tumors).We found the significant relationship between the risk of malignant tumor and occupational radiation factor,and the RR of solid cancer and total malignant tumor were 1.31 (95％ CI:1.11-1.55) and 1.33 (95％ CI:1.13-1.57),respectively.In addition,the risk of lung cancer in medical diagnostic X-ray workers was significantly higher than that in control group (RR =1.45,95％ CI:1.00-2.09).Conclusions The incidence risk of lung cancer,solid caner and total malignant tumors in medical diagnostic X-ray workers was significantly higher than that in the control group,which might be associated with occupational exposure to ionizing radiation.

Objective To continue following up the cohort members in Jiangsu province who were the largest subgroup in Chinese medical X-ray workers cohort subgroups on radiation carcinogenesis and analysis the cancer risk of medical X-ray workers which might be induced by chronic low-dose ionizing radiation between 1997 and 2011.Methods A retrospective cohort study was utilized to accumulate data.Epicure was applied to compute cumulative person years (with module of Datab) and relative risk (including 95％ CI) of malignant tumor on exposed group(with module of AMFIT) while the factors such as sex and attained-age were adjusted in the cohort members.Results The 7 708 follow-up members included 3 668 medical X-ray workers.The cumulative person-year in the cohort members was 94 651.2 (1997-2011) and its lost rate was 5.79％.During the follow-up period,441 cases had became cancer patients.The relative risk of all cancers was 1.44 (95％ CI:1.18-1.75),so was the solid cancers.Significant elevated risks of cancer were found on lung (RR =1.95,95％ CI:1.30-2.92),esophagus (RR =3.04,95％ CI:1.20-7.70),lymphoma(RR =2.24,95％ CI:0.67-7.48),leukemia(RR =1.57,95 ％ CI:0.33-7.39),throat (RR =2.47) and thyroid (RR =2.80,95 ％ CI:0.24-32.26) among medical X-ray workers.However,The RR of malignant tumors might not be associated with occupational exposure to ionizing radiation if we considered the lost factors (RR =1.2,95％ CI:0.94-1.46)Conclusions The RR of malignant tumors such as the cancer on lung,esophagus,thyroid among the medical X-ray workers in Jiangsu province were enhanced which might be associated with occupational exposure to ionizing radiation.

@@

@@

Objective To verify the methodology for auditing dosimetric parameters in reference and non-reference conditions with thermoluminescent dosimeters (TLDs).Methods Under reference and non-reference conditions,the established TLD methods were used to observe the absorbed dose variations with depth,SSD,field size and 45 wedges for 10 photon beams at 5 hospitals.Dosimetric parameters,including doses at Dmax points in axis,on 5 electron beams of 9 MeV were measured.The measurement results were compared between the TLDs and plane parallel ionization chambers.Results For 6 MV photon beams,the relative deviation of between finger ionization chamber method and TLD chips was in the range of-1.7％ to 5.4％ under on-axis non-reference conditions,and-6.3％ to-0.6％ under off-axis non-reference conditions,respectively,all within the range of ≤ ± 7％ as required by the IAEA.The relative deviation between plane parallel chamber and TLD method was-2.3％ to 3.7％,within ± 5％ as required by the IAEA.Conclusions It is convenient and feasible to use TLD method for quality audits of dosimetric parameters in radiotherapy.

Objective To investigate the attitude toward and perception of the risk of nuclear power plant among the public residing in vicinity of nuclear power plant,as well as the related factors.Methods A face-to-face interview on perceived radiation risks was conducted among 1408 individuals in Liangyungang City, Jiangsu Province.where the Tianwan nuclear power plant was under construction.The four groups was defined according to the distance between the residence of the subjects and the Tianwan nuclear power plant:<4 km,4- 8 km,8-30 km and 30-50 km.A was used to collect information on education,working history,religion, perception of major industries hazards especially nuclear power plant,and major factors may influence their perceptions.Ordinal logistic regression model was used to analyze the data.Results About 91.18% of the interviewee heard about the nuclear power plant,35.36% of them had knowledge about Chernobyl nuclear power plant accident,71.05% of them believed that the nuclear power plant had no negative effects on environments, 37.03% of them believed that the nuclear energy was safe.74.27% of them believed that it was necessary for China to develop nuclear energy.63.29% of them supported the construction of the nuclear power plant in local area.Ordinal logistic regression analysis revealed that the higher education,higher family annual income,male, economic benefits from the nuclear power plant construction,and trust in local government having competency to handling emergencies were positive factors;otherwise,impression on nuclear power plant of bad influences on environment and health were negative factors.An inverted U-shaped with a right tailing relationship between negative attitudes toward nuclear power plant and distance to the plant was found.Conclusions Education, gender,family annual income and expectation of economic benefit returns were the major factors influencing the perception of and attitudes toward nuclear power plant.More works needed to be done to mitigate the negative attitude of the residents in vicinity of nuclear power plant and enhance the public acceptability .

Objective To explore the dosimetric verification method for absorbed dose and twodimensional dose distribution generated through multi-leaf collimator in radiotherapy.Methods A total of 8 medical accelerators were selected in Jiangsu province.Under 6 MV X-rays with a 5 cm × 5 cm field,the thermoluminescent dosimeter (TLD) and EBT3 radiochromic film (RCF) were used to audit the values calculated by treatment planning system (TPS).RCF was used to verify two-dimensional dose distribution under the 6 MV MLC beams for intensity modulated radiation therapy (IMRT).Results The relative dose deviation was from-1.4％ to 6.8％ for TLD and from-1.8％ to 7.8％ for RCF,with 7 accelerators meeting with the IAEA deviation requirement of ± 5％.The passing rates of two-dimensional dose distribution were between 73.7％ and 97.0％,with 7 accelerators greater than 90％.Conclusions TLD and RCF are feasible and suitable for large-scale verification of IMRT TPS absorbed dose and twodimensional dose distribution.

Objective: To explore the long-term effects of radiation injury and to provide scientific basis for the evaluation of the effects of ionizing radiation injury by carrying out medical follow-up of patients involved in the " 5.7" radiative source accident in Nanjing in 2014. Methods: Through interviewing and investigating, we inquired about the new disease history of the exposed patients from rehabilitation treatment to medical follow-up peroid. Physical and laboratory examinations were carried out. According to relevant standards, physiological and biochemical indexes such as hematopoietic system, immune system, endocrine system, ophthalmology, circulatory system, digestive system, urinary system and bone mineral density were systematically evaluated, with the long-term effects being evaluated. Results: The patient′s vital signs were good without new diseases. The indexes of hematopoietic system, immune system and endocrine system tended to be normal, the circulatory system, digestive system and urinary system showed degenerative changes, the ophthalmic examination showed visual acuity continue to decline, and bone mineral density examination indicated low bone mass. Conclusions Physiological and biochemical indicators of the patients gradually returned to normal without obvious symptoms of radiation damage. Further medical follow-up observation still needs to continue.