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  • 28 December 2018 Volume 27 Issue 6
      
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  • The internal dose evaluation for transuranic nuclide-contaminated wounds
    WANG Wei, WU Mengmeng, WANG Chuangao, LUO Zhiping
    2018, 27(6): 523-527. https://doi.org/10.13491/j.issn.1004-714x.2018.06.001
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    Objective To compare the internal doses for transuranic nuclide-contaminated wounds by using ICRP wound biokinetic model and injection model recommended by ICRP 78 publication, and acquaint with the distribution of organ doses.Methods As an example, the effective dose and the distribution of organ equivalent doses caused by unit activity of 241Am (M class, Particle) were calculated by above two models, and the intake retention/excretion fraction curves in some organs (liver, bone, etc.) and some biological samples (urine, feces, etc.) were also studied.Results The deviation of effective doses estimated by the above two models was about 18.5%. The organ equivalent doses caused by 241Am (M class, Particle) through wound were in the order of bone surface, liver and red bone marrow. The intake retention fraction for the whole body was high, and it was hard to be excreted. The intake retention fraction in bone and liver increased significantly with time, while the excretion fraction in urine and feces were low and hardly changed.Conclusion The deviation of internal doses for transuranic nuclides-contaminated wounds estimated by using the two present models is relatively large, further studies are still needed.
  • Analysis of the individual occupational external exposure monitoring results of a tertiary hospital in Urumqi 2010-2016
    LEI Shuqin, SUN Xiaona, ZHU Dongsheng, WANG Yuwen
    2018, 27(6): 528-530. https://doi.org/10.13491/j.issn.1004-714x.2018.06.002
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    Objective This paper gives an overview of spread of occupational external exposure for monitoring individual by analyzing the exposure dosage of medical personnel within radiology department of a tertiary hospital in the city of Urumqi from 2010 to 2016.Methods Under the regulation of "Specifications of individual monitoring for occupational external exposure"(GBZ 128-2016), LiF(Mg, Cu, P) thermoluminescent dosimetry(TLD) is applied for the results and data analysis.Results From 2010 to 2016, the per capita annual effective doses of radiation workers in a top three hospital in Urumqi were:1.02 mSv 1.02 mSv 1.01 mSv 0.56 mSv 0.32 mSv 0.39 mSv 0.41 mSv and the 7-years average dose was 0.56 mSv. The number of monitoring individuals increased during the seven year period, the annual effective amount per capita, however, appears to be in a downward trend and a relatively stable level.Conclusion The medical personnel in a tertiary hospital, Urumqi have safety working environment as their annual effective dose per capita is in compliance with national standard. Nonetheless, nuclear medicine and interventional radiography should have the priority in exposure control.
  • Analysis of occupational exposure dose for some workers in PET/CT radiology departments of Fujian
    CHEN Xindi, QING Yunhua, GUO Jinrui, GUO Huozhong
    2018, 27(6): 531-532,535. https://doi.org/10.13491/j.issn.1004-714x.2018.06.003
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    Objective Analysis and evaluation of occupational exposure dose for workers in PET/CT radiology departments of Fujian.Methods According to the monitoring results of ambient dose equivalent rate and personal dose equivalent of radiation works around 5 PET/CT workplaces in Fujian from 2014 to 2016, The occupational exposure doses of PET/CT radiation workers were analyzed and compared with the national standard dose limit.Results The average annual individual effective dose of radiation workers was 0.50 mSv, and the annual effective dose of all radiation workers was less than 5 mSv. Without personal protection measures, the estimated annual maximum radiation doses for hand, head, neck and chest positions of radiation workers engaged in radiopharmaceuticals, injection and PET/CT co-room positioning were 549.0, 137.4 and 134.0 mSv, respectively.Conclusion Under the normal working conditions, the occupational exposure dose of radiation workers is at a low level, which meets the relevant requirements. Without effective personal protective measures, the occupational exposure dose of radiation workers will exceed the national standard on occupational exposure limit.
  • Analysis of the evaluation results on occupational disease hazard control effects in radio-diagnosis projects during 2014-2016 in Zhaoqing City
    LI Deyong, HUANG Boyue, LIU Fuguang, WANG Conglei, CHEN Xiao
    2018, 27(6): 533-535. https://doi.org/10.13491/j.issn.1004-714x.2018.06.004
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    Objective To analyze the evaluation results of the occupational hazard control effects in 41 radio-diagnostic projects during 2014-2016 in Zhaoqing, timely find out the existing problems and probe into the solutions and countermeasures.Methods The control effect evaluation items and construction units were classified, and the evaluation results of the control effects, the relevant data and the main evaluation contents were analyzed.Results There existed different levels of deficiencies in protection measures and management.For examples, pass rates of the room size, provision and use of personal protective equipment, file management and radiation workers training were only 75.6%, 70.7%, 68.3% and 80.5%, respectively.Conclusion It is necessary to further strengthen the legal concept and awareness of radiation protection of construction units, standardize the radiation protection management of construction units, and strengthen the publicity and law enforcement of radiological health in the administrative departments of public health.
  • Application frequency and distribution of X-ray diagnostic in Urumqi in 2016
    LIU Feng, SUN Xiaona, ZHANG Yong, WANG Yuwen
    2018, 27(6): 536-538,542. https://doi.org/10.13491/j.issn.1004-714x.2018.06.005
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    Objective To understand the allocation of radiological diagnostic equipment and the frequency of medical radiation exposure in the medical institutions in Urumqi, in order to provide the basis for the reasonable application of medical radiation technology.Methods 174 medical X-ray diagnostic institutions in Urumqi were investigated and analyzed by means of general survey.Results The frequency of routine X-ray diagnostic examination in Urumqi was 757.7 person-times per 1 000 population. The frequency of CT examination was 349 person-times per 1 000 population. And others X-ray diagnoses were 65.6 person-times per 1 000 population. Comparing the three different age groups, the majority of breast radiographs were taken in 0~15 years old group, while the frequency of mammography was greater in the group over 40 years of age than in the other two age groups. The frequency of X-ray diagnostic examination in different age groups was significantly higher in the older group than in the younger group. The frequency of female X-ray diagnosis was slightly higher than that of male's. There were significant differences in X-ray diagnosis between the three age groupsof 0~15 year old、15~40 year old and more than 40 year old (χ2=82.6 P<0.05;χ2=134.2 P<0.05;χ2=7.15 P<0.05).Conclusion In X-ray diagnostic examination, the CT examination has become a major means second only to the X-ray photography examination. The frequency of X-ray diagnostic examination varies among different age groups, suggesting that more attention should be paid to the frequency of X-ray exposure in older age groups. Through this survey, the related regulatory authorities should strengthen the supervision and management of radiation protection in medical institutions, to ensure the justification of diagnostic radiology and radio therapy.
  • Study of the effect of water phantom setting patterns on CT
    ZHU Weijie, FENG Zechen, HAO Kun, XU Hui
    2018, 27(6): 539-542. https://doi.org/10.13491/j.issn.1004-714x.2018.06.006
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    Objective To compare the effects of two types of phantom setting methods (suspension and place-on-couch) on the CT value (water), noise and uniformity of performance test results, and to find out which mehtod is more reasonable.Methods According to the method in GB 17589-2011, two kinds of phantom place patterns were tested:suspend the CT-WV17 phantom on-the phantom box or directly place the CT-WV17 on couch. With the same scanning parameters, the phantom was scanned for 5 times at each setting patterns, and the CT value (water), noise and uniformity on the images were measured.Results For the CT value (water), the results were averaged to be (0.39±1.49) HU and (1.00±1.83) HU for different phantom setting patterns, respectively, and the difference was significant (t=-2.55, P=0.022). In noise test, the results were averaged to be (0.23±0.06) and (0.25±0.08) for the two methods, respectively, and the difference was also significant (t=-3.38,P=0.004). In the unifomity test, the averaged results were (0.47±0.66) HU and (-0.06±1.82) HU for the two setting patterns, respectively, the significant difference (t=4.25,P=0.001) was also observed.Conclusion Carbon fiber couch has a potential impact on CT value (water), noise and uniformity. When testing CT value (water), noise and uniformity, the phantom-suspension should be used.
  • Investigation and analysis of the application frequency of medical X-CT and the dose in Fujian Province in 2016
    ZHENG Senxing, ZHANG Yan, HUANG Lihua, ZHENG Qishan, LIU Pan, GUO Huozhong, ZOU Tianlu, YAN Jianming
    2018, 27(6): 543-546,561. https://doi.org/10.13491/j.issn.1004-714x.2018.06.007
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    Objective To estimate the application frequency of medical X-CT and the collective effective dose in Fujian province in 2016.Methods By randomly sampling, 30 hospitals from 9 cities in Fujian province were investigated. The application information was read out from the Medical Image Archiving and Communication System (PACS) in each hospital. For the dose survey, DICOM files for 615 examinees were read out. The provincial application frequency and collective dose were estimated using population information.Results There were 72 sets of CT in the sampled hospitals, and they performed 1 556 514 times of examinations throughout a year. The application frequency of CT examination in Fujian province was estimated to be 311.6 person·times per 1 000 population, and the collective effective dose was estimated to be 8 776 person·Sv in 2016.Conclusion The application frequency of medical X-CT in Fujianprovince in 2016 significantly increased by compared to the national level in the Ninth Five-year Plan. Adjust CT scan parameters could decrease the patient dose effectively.
  • Measurement and Analysis of Radiation field in the Surgical Standing Areas during ERCP
    NIU Fei, YANG Shuhui, MIN Nan, ZHANG Lin, SONG Gang, ZHU Jianguo
    2018, 27(6): 547-551. https://doi.org/10.13491/j.issn.1004-714x.2018.06.008
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    Objective To measure and evaluate the radiation dose distribution characteristics in the standing areas of the operator during endoscopic retrograde cholangiopancreatography (ERCP), and to provide radiation dose data for the protection of ERCP endoscopist.Methods The areas that ERCP operators often stay in during exposure were divided into 40 test points. Five data were measured at each test point according to different altitudes. The ambient dose equivalent rate was measured by X and gamma radiation dose rate meter.Results The ambient dose equivalent rate of the operator's standing area was 2.3~386.0 μSv/h. Generally, the closer to the center of the irradiation field, the higher the ambient dose equivalent rate around it. For the same position, the dose equivalent rate around the head, chest, abdomen and lower limb height is close, while the dose equivalent rate around the foot is slightly lower, but there were some exceptions.Conclusion The higher ambient dose rates in the standing area of ERCP surgeons are mainly obtained in the areas where the operators often stand. Therefore, effective protective measures must be taken to ensure the health and safety of the ERCP surgeons.
  • Analysis of X-ray CT quality control testing and radiation protection monitoring in Zigong City
    LIU Ke, HU Han, HOU Zhanxian
    2018, 27(6): 552-554. https://doi.org/10.13491/j.issn.1004-714x.2018.06.009
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    Objective To understand the performance of the X-ray CT scanners and the protection effect of the CT rooms in Zigong City, quality control testing of all 26 X-ray CT scanners and radiation protection detection of all 26 CT rooms were conducted, so as to study the measures to improve the performance of CT equipment and the protection effect of the CT room.Methods According to the methods and requirements proposed by the quality assurance test specification of X-ray computed tomography equipment (GB 17589-2011), the requirements of radiological protection for medical X-ray diagnosis (GBZ 130-2013), and the standards of radiological health protection for X-ray computed tomography (GBZ 165-2012), quality control testing and evaluation was conducted.Results The qualified rates of weighted CT dose index, high-contrast resolution, low contrast detectability, CT value (water), noise, accuracy of locating light, deviation of reconstructed slice thickness and positional accuracy of diagnostic couch were all reached to 100%. The qualified rate of uniformity of CT number was 96.2%, and the qualified rate of linearity of CT number was 92.3%. The quality control test indicators of 23 CT machines are all qualified, with a total pass rate of 88.5%. The peripheral dose equivalent rate of only 1 CT room in the 26 CT rooms exceeds 2.5 μSv/h, and the pass rate was 96.2%.Conclusion The qualified rates of weighted CT dose index, high-contrast resolution, low contrast detectability, CT number of water, noise, accuracy of locating light, deviation of reconstructed slice thickness and positional accuracy of diagnostic couch were high, but the qualified rate of uniformity and linearity of CT number were relatively low. There were still unqualified monitoring points in radiological protection monitoring for CT rooms. Therefore, quality control and radiological protection should be further strengthened.
  • Investigation and analysis of medical radiation protection in medical institutions in Lhasa, Tibet, 2016-2017
    XIE Borong, ZHANG Qiang, WU Fang, YAN Xianmeng, DAWA Zhaxi
    2018, 27(6): 555-557. https://doi.org/10.13491/j.issn.1004-714x.2018.06.010
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    Objective To understand the current status of medical radiation protection in Lhasa, Tibet.Methods According to the requirements of the "Working Programme for Medical Radiation Protection Monitoring in Medical and Health Institutions", some medical institutions in Lhasa were selected to test the radiation protection and equipment performance of the radiation workplace, and the results were statistically analyzed.Results A total of 24 medical institutions, 68 equipment and 64 workplaces were monitored in two years, with a pass rate of 75.00% and 92.19% respectively. In 2016, 5 medical institutions were monitored, contained 22 radiotherapy equipment and 20 radiation workplaces, with a pass rate of 59.09% and 75.0% respectively. In 2017, 19 medical institutions were monitored, contained 46 radiotherapy equipment and 44 radiation workplaces, with a pass rate of 82.61% and 100.0% respectively.Conclusion The performance of radiology diagnosis and radiotherapy equipment and the monitoring rate of workplace in Tibet medical institutions are relatively low, and the monitoring pass rate is not high. Relevant parties should pay attention to and strengthen related work.
  • Effect of different water phantom diameters and reconstruction slice thicknesses on CT image noise
    ZHAO Xipeng, XU Hui, HUANG Zhuo, YUE Baorong, NIU Yantao
    2018, 27(6): 558-561. https://doi.org/10.13491/j.issn.1004-714x.2018.06.011
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    Objective To study the influence of different water phantom diameters, reconstruction slice thicknesses and doses on CT image noise, discuss the reasonable diameter range of the water phantom in the CT quality control testing, and provide data to improve the standard of CT quality control testing in China.Methods The axial scanning mode of the CT of Revolution type produced by GE company was used. Under the conditions of different doses of CTDIW 30.20 mGy (120 kV, 200 mAs) and 49.82 mGy (120 kV, 330 mAs), and different reconstruction slice thicknesses of 5 mm and 10 mm, the water phantom with the diameters of 16, 18, 20, 22 and 24 cm was scanned and its CT values and image noises were measured. The differences of the image noises were compared under different water phantom diameters, thicknesses and doses.Results The value of image noise amplified with the increase of the diameter of the water phantom, and decreased with the increase of the dose. The noise values with the water phantom diameters of 24 cm and 22 cm exceeded the existing testing standard. The noise decreased with the increase of the thickness of the slice thickness.Conclusion The measurement results of image noise are related to factors such as the dose, the diameter of the water phantom, the reconstruction thickness, etc. In the noise measurement of CT quality control testing, the dose, slice thickness, and the size of the water phantom are required to be selected. The results show that the range between 18 cm and 22 cm may be a reasonable value for the diameter of water phantom on a dose of close to 50 mGy.
  • Study on the design of shielding of low-background anti-compton measurement system
    ZHOU Shuli, LUO Zhiping, PANG Hongchao, LIU Yang, WU Jianhua, WANG Jianchao
    2018, 27(6): 562-566. https://doi.org/10.13491/j.issn.1004-714x.2018.06.012
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    Objective According to the natural radiation sources, a set of shielding for the low-background anti-compton measurement system is designed.Methods The model of detector and shield is established by Geant 4 Monte Carlo program. The main natural background radiation is input into the program as the source term. The structure and size of shield for the low-background anti-compton measurement system were simulated and optimized. The simulation results were verified by experimental measurements.Results The shielding structures of 10 cm lead, 8 cm boron-containing polyethylene, 2 cm lead, and 1mm oxygen-free copper lining from outside to inside were determed. The experimental results are in good agreement with the simulation results, and the laws reflect consistency.The integrated background counting rates in the measured energy range of 50~2000 keV was 1.72 cps.Conclusion The structure and size of shielding layer of the low background anti-compton measurement system are optimized, and by adding boron-containing polyethylene interlayer to reduce the background count rates caused by thermal neutrons and fast neutrons. The experimental results verified the rationality and feasibility of the design scheme.
  • A study for measuring radionuclides in whole diet by gamma spectrometry
    PANG Chaoya, TUO Fei, YANG Baolu
    2018, 27(6): 567-569,588. https://doi.org/10.13491/j.issn.1004-714x.2018.06.013
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    Objective Establishing a method for measuring the activity concentration of radionuclides in whole diet based on a broad-energy HPGe detector BE5030 model.Methods Whole diet samples were collected by "Dupllicate Portion Technique" and were measured by a broad-energy HPGe gamma spectrometer BE5030 model. The reliability of source-less efficiency calibration was verified by measuring a rice powder standard source with two different calibration methods. The efficiency calibration was carried out with LabSOCS software, and the activity concentration and daily intake of radionuclides in the samples were calculated.Results The results of source-less efficiency calibration were acceptable. Natural radionuclides 226Ra and 40K were detected in all the samples, the average activity concentration were 0.31 and 141 Bq/kg (dry weight), and the average daily intake was 0.21 and 95 Bq/d, respectively. 238U and artificial radionuclide 137Cs were not detected. 210Pb and 228Ra were detected in some samples.Conclusion The source-less calibration technique based on LabSOCS software could better simulated the detection efficiency and could be used to calibrate the efficiency for whole diet samples. The activity concentration of all radionuclides detected were within the national standard limits. Further research remain to be done in order to homogenize whole diet samples better and establish a "whole diet element library".
  • Effect of atmospheric pressure on the radon exhalation from the medium surface
    LIU Yan, ZHANG Jimian, YUAN Jiulin, SHAN Jian, YU Jinwei
    2018, 27(6): 570-572. https://doi.org/10.13491/j.issn.1004-714x.2018.06.014
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    Objective To acquaint the effect of atmospheric pressure changes on radon exhalation from the medium surface throughout a day.Methods Based on the double-room and open-loop balance method, radon exhalation rates in every 30 minutes were measured on a radon exhalation rate reference standard device throughout a day. The effect of atmospheric pressure on radon exhalation rate was analyzed based on the timely values of radon exhalation rate and atmospheric pressure. The change rate of the radon exhalation rate in one day was plotted and compared with the change rule of the in one day.Results Radon exhalation rate from the surface of the measured sample varied from 1.5912 Bq·m-2·s-1 to 1.9509 Bq·m-2·s-1 throughout a day. The high radon exhalation rate appeared in the low pressure range.Conclusion The radon exhalation from the surface of medium increases with the decrease of atmospheric pressure, but the decrease of radon exhalation was not obvious when the pressure increases.
  • Investigation on the levels of total alpha and total beta radioactivity in source water in the areas with three nuclear facilities in Sichuan Province
    ZHANG Yang, LI Linyu, HE Liangguo, WEN Xiangmin
    2018, 27(6): 573-575. https://doi.org/10.13491/j.issn.1004-714x.2018.06.015
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    Objective To investigate the total alpha and total beta radioactivity levels in source water in the areas with three nuclear facilities in Sichuan Province, and provide baseline database for radioactivity level in source water in the areas with nuclear facilities.Methods According to the national standard "Standard examination methods for drinking water-Radiological parameters"(GB/T 5750.13-2006),the total alpha and total beta radioactivity in source water in the areas with three nuclear facilities in Sichuan province were investigated.Results The total alpha activity in source water in the areas ranged from 0.016 Bq/L to 0.188 Bq/L, andthe total beta activity was in a range of 0.028~0.229 Bq/L. Both the levels of total alpha and total beta activity were at the national average middle and lower levels. They still belong to the normal background levels.Conclusion The levels of total alpha and total beta radioactivity in source water in the areas with three nuclear facilities are lower than the national standard set for drinking water quality (GB 5749-2006).
  • Monitoring results of individual dose of nuclear workers in Ningxia during 2013-2016
    KONG Qingyu, LIU Jing, LU Guicai, JI Xuli, LI Hongcheng
    2018, 27(6): 576-578. https://doi.org/10.13491/j.issn.1004-714x.2018.06.016
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    Objective To learn and master the radiation dose of nuclear workers in Ningxia region, protect the health of radiation workers, discover the weak links in radiation protection, and prevent occupational radiation diseases.Methods Thermoluminescence personal dose measurement method was applied to monitor the nuclear medicine radiation workers from 2013 to 2016 and analyzed the results.Results In 2013-2016, a total of 364 person-times were monitored for nuclear medicine radiation workers. The per capita annual effective doses were 0.99 mSv/a, 1.76 mSv/a, 1.19mSv/a, and 1.06 mSv/a respectively; The top three nuclear workers weretechnician (1.6 mSv/a) physician (1.32 mSv/a) and physicist (1.24 mSv/a).Conclusion The per capita annual effectivedose of nuclear workers in Ningxia second to the interventional radiological radiologists, it ranks second in the occupational category of all radiological workers. We should strength the radiation protection and monitoring and it is necessary to rationally arrange work according to personnel in different works so as to protect radiation workers and avoid excessive dose exposure.
  • Study on detection limit of direct measurement system for internal exposure using anticoincidence method
    PANG Hongchao, WANG Ying, YUAN Guojun, WU Mengmeng, GUO Luzhen, LUO Zhiping
    2018, 27(6): 579-581. https://doi.org/10.13491/j.issn.1004-714x.2018.06.017
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    Objective At present, there is a problem that the lower detection limit of lung counter is higher in the direct measurement of internal exposure of transuranic nuclides. In this paper, the anti-coincidence method is used to reduce the system's background and further reduce the detection limit of the system.Methods A new cosmic ray detector based on anti-coincidence method were established in the lung counter system to study the influence of hard components such as muon in cosmic rays on the background of the lung counter system. The cosmic ray detecting system was organized by a large area of plastic scintillator (140 cm (length)×110 cm(width)×5 cm(height)) and anti-coincidence circuit.Results For the energy between 6 keV and 2 MeV, the background count rate of this system decrease from 2.5 cps to 2.2 cps by using the anti-coincidence technique. And the detection limits of 241Am (59.5 keV) and 239Pu (13.6 keV) after 1 800 seconds counting could reach 1.4 Bq and 1700 Bq, respectively.Conclusion In the process of direct measurement of transuranium nuclides with lung counter, the use of anti-coincidence method to reduce the hard component of cosmic rays can better reduce the background of some systems and play a role in reducing the lower limit of radionuclide detection.
  • Preliminary study on air ionization chamber for monitoring the dose of proton cyclotron at middle and low energy
    HOU Shigang, WANG Feng, SONG Guofang, XIE Huaidong
    2018, 27(6): 582-585. https://doi.org/10.13491/j.issn.1004-714x.2018.06.018
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    Objective To develop an air ionization chamber for measuring gamma fields generated by a middle and low energy proton cyclotrons.Methods The electric field distribution of the air ionization chamber and the energy deposition of gamma rays in the ionization chamber were simulated by finite element method and Monte Carlo method respectively. The simulation results determine the mechanical size and structure of each part of the ionization chamber. A low current amplifier was designed and preliminary calibration test was carried out according to the actual dose rate when the low and medium energy cyclotron was running.Results The simulation results show that the sensitivity of the air ionization chamber is within ±30% in range of 1 MeV~8 MeV photons, and the signal output noise is less than 2 mV. The operation of the chamber is stable.Conclusion The preliminary test results show that the ionization chamber works stably in operation and has a wide energy response range, which meets the requirements of the design specifications.
  • Analysis of the levels of gross α and gross β radioactivity in atmospheric fallout during 2013-2014 in Shenzhen City
    LIU Yan, FENG Jiangping, PENG lijun, GUO Jianfeng, SHI Jinsong
    2018, 27(6): 586-589. https://doi.org/10.13491/j.issn.1004-714x.2018.06.019
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    Objective To acquaint the levels of grossαand gross β radioactivity in the fallouts in Shenzhen City, and to compare with their previous values.Methods Fallouts samples were collected according to the "Environmental air quality monitoring specifications", and the radioactivity of gross αand gross β in the fallouts was analyzed by taking "Standard test method for drinking water-Radioactivity index" as reference.Results The averaged gross α ranged from 0.078 Bq/(m2·month) to 7.02 Bq/(m2·month), and the value of gross βwas in a rage of 2.67-10.69 Bq/(m2·month).Conclusion The results were in the same levels as those reported by the CDC of Shenzhen (1993-2005) and the Guangdong Environmental Radiation Monitoring Center (2007-2010).
  • Decision threshold and detection limit in low-levels of radioactivity measurements
    WANG Chuangao, LUO Zhiping, PANG Hongchao, YIN Yunyun, ZHENG Guowen, XU Yongjun, LOU Hailin, WANG Zhongwen, LI Ruirui
    2018, 27(6): 590-594. https://doi.org/10.13491/j.issn.1004-714x.2018.06.020
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    Objective The calculation methods for decision threshold and detection limit of radioactivity measurement for low background were discussed.Methods Based on the data from 18 biological samples measured by Alpha spectrometer, formulas of decision threshold and detection limit given in RSG1.2(IAEA), NUREG 1576(USA)and AQ48(IAEA) were used and discussed.Results Parts of the results decided by these three kinds of formulas would be entirely different,which indicated that formulas of NUREG 1576 and AQ48 were much more conservative than the formulas of RSG1.2 for low background counts(as<100).Conclusion To ensure the reliability when judging the measured data, formulas of decision threshold and detection limit must be chosen according to the actual condition (such as background counts, background count time and gross count time, etc.), especially in low-level radioactivity measurements.
  • Study on response time performance of RJ32-2106P and AT1123 X-γ ray dose rate meters
    XU Hui, ZHAO Xipeng, YUE Baorong, FENG Zechen, HUANG Zhuo
    2018, 27(6): 595-598. https://doi.org/10.13491/j.issn.1004-714x.2018.06.021
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    Objective To investigate the problems existing in radiological protection monitoring of medical X-ray diagnostic workplaces in China, compare the response time performance of domestic and imported X-γ ray dose rate meters, and evaluate their applicability in radiation protection detection of medical X-ray diagnostic workplaces.Methods On a medical X-ray radiography device, the voltage(70 kV) was fixed. High middle and low doses were obtained by setting different tube currents and the exposure time was increased from 10 ms to 1 000 ms. The equivalent dose rate readings of the two kinds of X-γ ray dose rate meters under different exposure time were recorded.Results The response time of domestic RJ32-2106P X-γ ray dose rate meters was 160 ms for the low dose range, and 50~64 ms for both middle and high dose range. The response time of AT1123 was about 80~100 ms for all three dosage ranges.Conclusion The equipment that can measure the short time beam and the pulse radiation field should be selected in the radiological protection monitoring of medical X-ray diagnostic room. RJ32-2106P and AT1123X-γ ray dose rate meters both have a time response of less than 200 ms at different dose levels. They are suitable for radiological protection detection of medical X-ray diagnostic rooms.
  • Comparison and analysis of intercomparison results of external irradiation individual dose monitoring in Jiangsu Province
    YANG Xiaoyong, CHEN Wei, QIN Yongchun, WANG Furu, CHEN Qun
    2018, 27(6): 599-601. https://doi.org/10.13491/j.issn.1004-714x.2018.06.022
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    Objective To test the personal dosimetry performance of personal dose monitoring service agencies in Jiangsu.Methods Thirty-three agencies were involved in the intercomparison. Personal dosimeters were irradiated in Jiangsu institute of metrology. The measure reports were submitted by each of the institutions. Single group performance(Pi), deviation value(B), deviation standard deviation(S) and comprehensive performance(√B2+S2) were calculated according to the standard GBZ 207-2016《Testing criteria of personnel dosimetry performace for external exposure》. Then the institutions were categorized by the judgments of their single group and comprehensive performance.Results In 2018, the pass rate of personal dosimetry performance in Jiangsu was 84.4%, and the outstanding rate was 18.8%.Conclusion It is very necessary to perform such intercomparison periodically for quality control in individual monitoring of external exposure.
  • Monitoring and evaluation of radiation environmental impact of sinking X-ray inspection room
    XIANG Huiyun, BI Xinlin, ZHENG Huangting, YUAN Jilong, XU Mingfa
    2018, 27(6): 602-604. https://doi.org/10.13491/j.issn.1004-714x.2018.06.023
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    Objective Using a sinking X-ray inspection room as a research object, monitoring the radiation dose rate level around the inspection room,the results were analyzed and evaluated in conjunction with relevant standards. To evaluate the advantages and disadvantages of the design of this type of inspection room, and to provide a scientific basis for strengthening the radiation safety supervision of this type of X-ray inspection room.Methods Using appropriate instruments to monitor the ambient dose equivalent rate of the environment around the inspection room, and to carry out theoretical estimation according to the shielding specifications, and to carry out evaluation based on actual measurement results and estimation results.Result The radiation dose rate around the interest points of the sinking type flaw detection room meets the requirements of relevant standards.Conclusion The environmental management of atypical X-ray inspection rooms should be strengthened to prevent the hidden radiation safety hazards.
  • Analysis and suggestions on the case of radioactive protector were not used for the patient in a hospital
    SONG Jiaojian, CHEN Qingmei, CHEN Rui, ZHENG Chenglong
    2018, 27(6): 605-607. https://doi.org/10.13491/j.issn.1004-714x.2018.06.024
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    Objective To exchange experiences in radioactive supervision and emphasize the importance of reasonable protection for the patients in radioactive examinations and protect the public health effectively.Methods Analyze a administrative case in which radioactive protector were not accurately used for the patient in a hospital.Results The case was concluded, but there are some irregularities in the equipment,renewal and store of the radioactive protector. radioactive protection consciousness are also need to be improved.Conclusion Opinions and suggestions from the aspects about hospital managemen,radioactive health supervision,publicity and training should be put forward on how to improve radioactive protection awareness effectively.
  • Problems and suggestions on the construction of professional norms for employees of third-party testing organization in radiation diagnosis and treatment industry
    WANG Guiqing, ZHANG Zhucun, CHEN Xiaojie, SHAO Yanjie, XU Rong, JIANG Fajing, HAN Zhengwei, LIU Xuefeng, KONG Lingyan
    2018, 27(6): 608-610. https://doi.org/10.13491/j.issn.1004-714x.2018.06.025
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    Objective To strengthen the construction of professional norms for employees of third-party testing organization in radiation diagnosis and treatment industry, and to improve the occupation moral quality of employees.Methods Consulting literature and collecting data.Results The behavioral requirements and the existing problems of the construction of professional norms of employees of third-party testing organization was discussed in this paper.Conclusion Some suggestions were put forward to solve these problems.
  • The hope of medical radiation protection and monitoring in Tibet can be seen from group assistance
    ZHANG Qiang, XIE Rongbo, DAWA Zhaxi, YAN Xianmeng, LI Bin
    2018, 27(6): 611-613,620. https://doi.org/10.13491/j.issn.1004-714x.2018.06.026
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    Objective To understand the current situation of medical radiation protection in Tibet. To ensure the health and safety of medical radiation workers, patients and the public in medical and health institutions in Tibet.Methods Based on the data accumulated in many years of medical radiation protection monitoring work, this paper analyzed the development process with Tibetan characteristics by taking some cities as examples. Based on the characteristics of medical radiation monitoring in Tibet, combined with the practical experience of group assistance and assistance for medical radiation monitoring in Tibet, this paper analyzed the factors affecting the health and safety of Tibetan radiation workers and provided corresponding countermeasures.Results The foundation of medical radiation monitoring in Tibet was weak, and the routine monitoring, supervision and management were not available in actual medical and health institutions in the course of radiological diagnosis and treatment.Conclusion It is necessary to strengthen supervision and management in the construction, acceptance inspection and operation of medical and health institutions, and establish a local medical radiation monitoring team in Tibet under the working mode of group assistance, so as to improve the level of medical radiation monitoring in Tibet, effectively eliminate hidden dangers and ensure the long-term safe and stable operation of medical and health institutions.
  • Five core issues in radiation protection management of nuclear power plant
    WANG Chuan, ZHANG Qiang, ZENG Jinzhong, HE Junnan, NI Wei, WANG Ruijun, LI Houwen
    2018, 27(6): 614-617. https://doi.org/10.13491/j.issn.1004-714x.2018.06.027
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    In terms of radiation protection management of nuclear power plant, both management and technology are important. Combining the author's many years of experience, this paper introduces five core issues in radiation protection management of nuclear power plant from five aspects:radiation protection technology team, management program system, standardized technical file system, informatization management and experience feedback.
  • Application of PDCA cycle in occupational disease diagnosis file management
    QIN Zhanxia, ZHAO Yan, RONG Zhen, WU Jing, CHEN Shukun
    2018, 27(6): 618-620. https://doi.org/10.13491/j.issn.1004-714x.2018.06.028
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    Objective To improve the management level of occupational disease diagnosis files.Methods Through PDCA cycle theory, we find out the current problems in the management of occupational disease diagnosis files, analyze the reasons, formulate plans, and supervise and evaluate the results.Results The application of PDCA cycle in occupational disease diagnosis files can help us find problems in file management and fix them effectively. In the continuous PDCA cycles, the quality management level of occupational disease diagnosis files can be risen in a spiral.Conclusion The specific application of PDCA cycle theory in the management of occupational disease diagnosis files can improve the management level of occupational disease diagnosis files.
  • The depth dose characters of different tissue substitutes based on Eclipse
    MIAO Li, QIU Zhengshuai, CHENG Xiaoguo
    2018, 27(6): 621-623. https://doi.org/10.13491/j.issn.1004-714x.2018.06.029
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    Objective Researching the characters of depth dose deposition of different tissue substitutes.Methods The water phantom(20 cm×20 cm×20 cm)is built in Eclipse TPS, then different tissue substitutes models which assigned density and CT values are set up 3 cm under the water phantom surface at the center axis. A radiation field, 6 MV X-ray, 10 cm×10 cm, SSD=100 cm,is given to different models, then we extract the center axis depth dose which are used to compared with the one in pure water phantom.Results The dose curves in water phantom with air and lung appear second dose built-up effect below the inferior interface, and the rate of descend of the dose value is significantly slower then the one in pure water phantom. The depth dose values in the phantom included Muscle-Skeletal and Adipose-Tissue are mainly as same as the ones in pure water phantom, but the dose curve in Adipose-Tissue is slightly on top of the curve in pure water phantom; The depth of dose curves in Bone and AL model below the superior interface appear the second dose built-up effect, but the rate of descend of the dose value in them decreases rapidly below the inferior interface. All the curves tend to be parallel to the one in pure water phantom after a certain depth.Conclusion The second dose built-up effect will appear when X-ray passes through from low density substance to high density substance, and the greater of the density difference, the more obvious of the effect. The depth dose decreases rapidly when the X-ray passes through from high density substance to low density substance, and the greater density difference will lead to more obvious phenomenon. The depth dose characters can be useful in TPS planning design.
  • Application of VMAT-based hybrid intensity-modulated technique on tumor bed boost after Breast-conservative surgery for breast cancer
    ZHENG Yaqin, LIU Jianting, CHU Xuegang, CUI Tong, XING Yurong, XING Xiaofen
    2018, 27(6): 624-627. https://doi.org/10.13491/j.issn.1004-714x.2018.06.030
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    Objective To evaluate dosimetry advantage and clinical application of hybrid intensity-modulated radiotherapy with 3DCRT/VMAT in radiotherapy with tumor bed boost after breast-conservative surgery.Methods Ten patients with breast cancer after breast-conservative surgery were enrolled. Under the same optimization conditions, the VMAT-based hybrid planning (3DCRT+VMAT) and the IMRT-based hybrid planning (3DCRT+IMRT) are designed respectively.The conformity index (CI), homogeneity index (HI), volume of exposure dose on organs at risk in patients from two plans were compared.Results According to the hybrid plan of 3DCRT+VMAT, D95 of Planning Target Volume (PTV) is 50.29±0.25, which is superior to that from 3DCRT+IMRT, 50.69±0.20(P<0.05). There was neither statistical difference of D95 and PTV between two plans, nor difference of CI and HI of pretreatment gross tumor volume (PGTV). In the comparison with exposure dose volume delivered to the heart in two plans, the values of V30 and Dmean in the plan of 3DCRT+VMAT were lower than the ones in 3DCRT+ IMRT(P<0.05). Dmean of the contra-lateral breast in the 3DCRT+VMAT group is 1.31±0.44, that is inferior to the group of 3DCRT+IMRT, which is 1.88±0.28(P<0.05). While V5, V10, V20, Dmean of ipsilateral lung dose and Dmean of cardiac and contra-lateral lung dose had no statistical difference (P>0.05). The monitor units (MU) of 3DCRT/VMAT Plan were 31%(P<0.05) less than that of 3DCRT+IMRT Plan, while the average treatment time of the former plan was 38%(P<0.05) less than the latter.Conclusion Compared with the IMRT-based hybrid plan, the VMAT-based hybrid plan better protects the heart and the healthy breast while ensuring the conformity and uniformity of the target area, and significantly shortens the schedule execution time. Therefore, it has a high potential for clinical application.
  • Clinical study of radiation pneumonitis in patients with esophageal cancer and diabetes after intensity-modulated radiotherapy
    GUO Feng, DU Aonan, SHI Jinglei, SHEN Wenbin, LIU Yazhou, SUN Suping
    2018, 27(6): 628-630. https://doi.org/10.13491/j.issn.1004-714x.2018.06.031
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    Objective To analyze the accidence of radiation pneumonitis in patients with esophageal cancer with diabetes mellitus after intensity-modulated radiotherapy.Methods A retrospective analysis was performed in xuzhou tumor hospital from June 2015 to June 2017. 50 cases of diabetic patients with esophageal cancer as experimental group and 50 patients with non-diabetic esophageal cancer were selected as control group. The incidence of radiation pneumonia in patients with esophageal cancer was compared between the two groups.Result In the experimental group, the incidence of radiation pneumonitis was 34% in patients with esophageal cancer after IMRT. In the control group, the incidence of radiation pneumonitis was 14% after treatment. There were significant differences in incidence of radiation pneumonitis between two groups of esophageal cancer patients(P<0.05).Conclusion The incidence of radiation pneumonitis is more common in patients with esophageal cancer with diabetes after intensity modulated radiation therapy.
  • Research Progress of Ultraviolet exposure Evaluation method and Cataract Epidemiology
    LI Xin, LIU Yang
    2018, 27(6): 631-634. https://doi.org/10.13491/j.issn.1004-714x.2018.06.032
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    The phenomenon that the ozone layer cavity causes the enhancement of surface ultraviolet radiation has attracted wide attention. Cataract is one of the main diseases leading to blindness, which seriously affects people's quality of life. At present, UV exposure assessment studies include three levels:environmental radiation, individual exposure and ocular exposure. Epidemiological study focus on the relationship between the incidence of cataract and environmental ultraviolet radiation rather than ocular ultraviolet exposure. This paper will make a brief review on the UV exposure assessment methods and UV-induced cataract epidemiological investigations in these two aspects.