Procedures of health protection and control for COVID-19 during X-ray imaging examinations in Jiangsu province / 中华放射医学与防护杂志

X-ray imaging is an important method for the diagnosis of corona virus disease(COVID-19), but there is a risk of nosocomial infection during X-ray imaging diagnosis. By analyzing the process of X-ray imaging diagnosis and the possible infection factors in hospital, Jiangsu province took the lead in issuing the Guideline for the nosocomial infection prevention and control of X-ray imaging diagnosis of COVID-19. This guideline clarifies the basic requirements for controlling infections during X-ray imaging diagnosis, the specific measures for staff protection, disinfection of personnel and places, and the protection and disinfection of subjects, which is instructive for field work. It is worth noting that while focusing on controlling infections, the principle of optimal protection for medical exposure cannot be ignored.

Procedures of prevention and control of COVID-19 during X-ray imaging examinations in Jiangsu province / 中华放射医学与防护杂志

X-ray imaging is an important method for the diagnosis of corona virus disease(COVID-19), but there is a risk of nosocomial infection during X-ray imaging and diagnosis. By analyzing the process of X-ray imaging & diagnosis and the possible exposure factors in hospital, Jiangsu province took the lead in issuing the guideline for the nosocomial infection prevention and control of COVID-19 during X-ray imaging and diagnosis. This guideline clarifies the basic requirements for controlling infections during X-ray imaging and diagnosis, the specific measures for staff protection, disinfection of personnel and sites, and the protection and disinfection of subjects, which is instructive for on-site work. It is worth noting that while focusing on controlling infections, the principle of optimal protection for medical exposure cannot be ignored.

Cytogenetic analysis of the victim followed-up at 4 year after 192Ir radiation accident in Nanjing / 中华放射医学与防护杂志

Objective:To screen the indicators of retrospective dose estimation, based on 5 cytogenetic methods to assess the victim followed-up at 4 year after 192Ir radiation accident in Nanjing. Methods:The chromosome aberration (dic + r) assay, cytokinesis block micronucleus (MN) and nucleoplasmic bridge (NPB) assay, fluorescence in situ hybridization (FISH)-based and G banding-based translocation analysis were used to retrospective biological dose estimation. Results:The estimated doses of FISH-based and G banding -based analysis were 1.45 and 1.21 Gy respectively, which was similar to the biological dose estimated short time after the accident. However, the estimated doses by chromosome aberration, micronucleus and nucleoplasmic bridge method were 0.56, 0.45 and 0.41 Gy respectively, which were lower than the corresponding biodose. Correction factors were used to adjust the biodose.Conclusions:In the 4th years after exposure, the estimated biological doses by FISH-based and G banding-based translocation were consistent with the biodose.Therefore, the two methods were suitable for retrospective dose estimation, while correction factors should be considered in chromosome aberration method for retrospective dose estimation.

Survey on frequency of medical X-ray diagnosis in Jiangsu province / 中华放射医学与防护杂志

Objective To survey the frequency of medical X-ray diagnosis and estimate the medical exposure levels of Jiangsu province in 2016,so as to be able to improve effectively the protection against medical radiation exposure.Methods All medical institutions in the province were covered in the survey for their basic medical information by means of census method.Frequencies of diagnostic medical X-ray examination were studied using random sampling method in 31 medical institutions.A linear model was established by number of outpatients number of inpatients,number of staff and number of radiation workers to evaluate the medical examination frequency.Results A total of 9 248 pieces of medical X-ray diagnostic equipment by the end of 2016 in Jiangsu province,including 1 110 CT scanners.The total frequencies of diagnostic medical X-ray examination were estimated to be 911.45 examinations per 1 000 population,covering 239.25 per 1 000 for CT scanning.The number of medical X-ray diagnostic equipment increased by a factor of 0.8 while CT scanners by a factor of 3.6 compared to 1999.Medical X-ray diagnostic frequency raised by a factor of 3.2 while CT frequency by a factor of 15.1 compared with previous data.Conclusions The medical X-ray diagnostic frequencies in Jiangsu province was 1.9 times the value given in the UNSCEAR 2008 Report,close to those in some developed European countries.Compared with the study in 2015,the present study has made greater improvement in sampling technique for selection of hospitals and equipment,frequency estimation method and acquisition of influence factors.Estimates of medical X-ray diagnosis frequency are closer to actual level.Further improvement will be needed for the future survey,so as to further study medical exposure levels and to provide basic information for better patient protection.

Medical follow-up of exposed victims after the " 5.7" accident of radioactive source in Nanjing / 中华放射医学与防护杂志

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.

A 3-year follow-up cytogenetic observation on victims exposed to iridium-192 in a radioactive sourcer-loss accident in Nanjing City / 中国职业医学

OBJECTIVE: To observe the decay law of chromosome aberrations after 3 years iridium-192 radiation exposure in victims of Nanjing “5.7” radiation accident. METHODS: The peripheral blood of victims was collected 3 years after iridium-192 radiation exposure. The routine chromosome aberration analysis, micronucleus analysis and G-banding karyotype analysis were used to detect the chromosomal instability rate, the binuclear micronucleus rate and the stability distortion rate. A dose reconstruction was carried out based on the distortion results. RESULTS: The aberration frequency of dicentric(dic) and centric rings(r) was 6.5% after 3 years iridium-192 radiation exposure, which decreased to 31.0% at 6 days after exposure(the aberration frequency of dic and r was 21.0%). The estimated biological dose based on the aberration frequency of dic and r was 0.75 Gy, which is about 50.0% of the initial estimated dose(1.52 Gy) at 6 days after exposure. The micronucleus rate of the binuclear lymphocytes was 63.0‰, and the estimated biological dose based on the micronucleus rate was 0.71 Gy, which was similar to the estimated dose of aberration frequency of dic and r. The total frequency of chromosome aberration observed by karyotype analysis of G-bands by trypsin using Giemsa was 41.0%, the stability aberration frequency was 30.0%, and the translocation frequency was 15.0%. The result of dose reconstruction based on the translocation frequency was 1.50-1.89 Gy, which was very close to the initial estimated dose(1.52 Gy). CONCLUSION: The decay of unstable chromosome aberration may be influenced by many factors, more detailed data need to be accumulated to study the decay law. The use of stable chromosomal aberrations, especially translocation frequencies used in dose reconstruction in earlier exposures, is an ideal method.

Dosimetric verification on intensity modulated radiotherapy in Jiangsu province / 中华放射医学与防护杂志

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.

Risk analysis of malignant tumor among medical diagnostic X-ray workers during 1997-2011 in Jiangsu province / 中华放射医学与防护杂志

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.

Incidence risks of malignant tumor among medical diagnostic X-ray workers during 1950-2011 in Jiangsu, China / 中华放射医学与防护杂志

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.

Dosimetric verification for radiotherapy quality audit under reference and non-reference conditions in Jiangsu province / 中华放射医学与防护杂志

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.

Optimization of scanning parameters in children CT examination / 中华放射医学与防护杂志

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.

Cumulative skin dose estimates for the medical diagnostic X-ray workers in Jiangsu province from 1950 to 2011 / 中华放射医学与防护杂志

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.

Risk perception of the public living in vicinity of nuclear power plant / 中华放射医学与防护杂志

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 .