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  • 28 February 2017 Volume 26 Issue 1
      
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  • Effects of Fukushima Nuclear Accident on Activity Concentration of Cesium -134 and Cesium -137 of Marine Prod-ucts in Shandong
    CHEN Ying-min, XU Jiaang, MIN Nan, WANG Lei, CHEN Rui
    2017, 26(1): 1-3,8.
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    Objective To investigate radioactivity levels in coastal seafood in Shandong after the March 2011 Fukushima nuclear accident,and to study the radioactive effects on seafood in coastal areas of Shandong.Methods Sample collection and pretreatment were carried out according to the method of "Examination of Radioactive Materials for Foods-General Principle "(GB 14883.1-94). The samples of marine products were measured according to "Gamma Spectrometry Methed of Analysing Radionuclides in Biological Samples" (GB/T 16145-1995).The committed aborbed dose are estimated for residents receiving seafood according to "Basic Standards for Protection Against Ionizing Radiation and for the Safety of Radiation Sources" (GB 18871-2002).Results We collected 3 samples for each class in Yantai, Qingdao and Weihai of shandong,such as squillid of crustaceans, wahoo of fish,cuttlefish of mollusks class,kelp of plants category and clam of shellfish.The artificial nuclide cesium-137 was detected in each sample of squillid and wahoo in Yantai, Qingdao and Weihai,and cesium-137 was not detected in the other samples. Cesium-134 was not detected in all samples.The results showed that,squillid and wahoo,the activity concentration of cesium-137 ranged from 0.016 Bq/kg to 0.026 Bq/kg and from 0.051 Bq/kg to 0.096 Bq/kg, respectively.The annual equivalent effective doses derived from squillid and wahoo ingestion are 3.9×10-6mSv and 2.7×10-5mSv, respectively.Conclusion March 2011 Fukushima nuclear acciden did not cause the marine products to be polluted by radionuclide in coastal areas of Shandong.The annual equivalent effective dose derived from the marine products ingestion was at a safe level.
  • Simulation of Radionuclide Migration in Underground Water of a Uranium Tailing Based on MODFLOW Software
    LIU Zhong-ping, SHU Hui, LIU Qian-shun, LI Ya-jun
    2017, 26(1): 4-8.
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    Objective To study the time and space distribution of radionuclide of uranium tailing by means of numerical simulation in groundwater.Methods To select a uranium tailing in China as the research object and establish the radionuclide migration equation on the basis of the underground water dynamics model. When the uranium tailing retirs to 30 a,50 a,100 a,200 a,500 a,1000 a after, simulate the concentration distribution and largest migration distance of 238U and 226Ra in groundwater by using MODFLOW software and the calculation method of finite difference mesh.Results The activity concentration of 238U and 226Ra was 6.18 Bq/L, 0.76 Bq/L in the monitoring Well, when the uranium tailing retired after 1000 a.the maximum migration distance of 238U and 226Ra was 1.7 km, 0.7 km, respectively.Conclusion As the distance increased, the activity concentration of 238U and 226Ra decreased in groundwater. As time went on the activity concentration of 238U and 226Ra decreased rapidly at first, later tended to a stable value.
  • Detection and Analysis of Protective Performance of Medical Electron Linear Accelerator Based on IEC Standard
    WANG Hong-wei, HAO Ying-nan, HE Qiang, LV Zhi-zheng, WANG Chun-yu, CHEN Chong, FENG Wei, CHEN Da-wei
    2017, 26(1): 9-13.
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    Objective According to the IEC 60601-2-1 version 3.1, the protective performance of medical electron linear accelerator is comprehensively analyzed and detected, which will provides reference for the future use of this standard to detect similar equipment.Methods We carries on the field trials and testing on a 6MV medical electron linear accelerator radiation hazard protection related test items, and carry on the comparative analysis between our result and the standard request.Results The medical electron linear accelerator equipment and the operation of the safety interlock system testing content were in line with the standard requirements. Relative surface dose was 58.7%. M area on the patient plane X-ray radiation leak maximum rate was 1.34%. The mean value of X, Y measurements at different combinations of diaphragm conditions were 0.21%, 0.26%, respectively. Multi leaf collimator leakage radiation rate maximum was 3.46%. The maximum leakage radiation combination condition of outside the area M for the gantry was 0°, the beam limiting system was 0°, the X-ray radiation leak maximum rate was 0.11%, and average was 0.08%. Outside the patient plane X-ray radiation leak maximum rate was 0.25%, and the maximum value of ambient dose equivalent rate was 0.08μSv/h.Conclusion Protection against incorrect absorbed dose in the treatment volume, stray radiation in the radiation field, radiation in the patient plane outside the radiation field and the radiation safety for patients and others of the medical electron linear accelerator can reach the IEC 60601-2-1 standard protection requirements.
  • The Feasibility Study on Measurement of Natural Nuclides in Copper Concentrates by ICP-MS Technique
    Yan Wen-xun, Feng Ya-hui, Zhang Xiu, Zheng Jian-ming, Xu Song, Xu Xin-chun
    2017, 26(1): 14-15,18.
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    Objective To study the feasibility of measurement of 238U,232Th,226Ra and 40K in copper concentrates by ICP-MS technique.Methods ICP-MS was applied to characterize the concentration of 238U, 232Th, 226Ra and 40K in copper concentrates; the specific activity of natural nuclides were obtained by theoretical calculation using the concentration data, then HPGe γ spectrometer was employed to characterize the specific activity of natural nuclides in the copper concentrates compared with the data of specific activity obtained by ICP-MS and HPGe γ spectrometer respectively, and the feasibility of measurement of 238U,232Th,226Ra and 40K in copper concentrates by ICP-MS technique was judged.Results The relative error of specific activity by ICP-MS compared with HPGe γ spectrometer technique was less than 10%.Conclusion Specific activity of natural nuclides in copper concentrates can be characterized by ICP-MS technique, and ICP-MS technique can be applied to decide the value of the reference sample.
  • The Validation for Medical Accelerator and Radiotherapy Quality Assurance System
    MA Qiao, LIU Ming-zhe, LIU De-ming, LIU Ran
    2017, 26(1): 16-18.
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    Objective To evaluate the performance of medical accelerator and radiotherapy quality assurance system and discusse the influence factors and solutions.Methods According to some standards, to test the accelerator (LINAC), image guidance system (IGRT), radiation treatment planning system (TPS) and multi leaves collimator (MLC), and then evaluate the results according to the standards.Results The testing results show that the most of performance status of the medical linear accelerator is good, and the qualified rate is 92.3%. Radiotherapy quality assurance system is not perfect.Conclusion The use of 2D flat chamber has some limitations for the radiation dose verification and wild detection. The accuracy of finger chamber and 3D water tank is higher. IGRT, TPS and MLC are very important for the validation of radiotherapy quality assurance system.
  • Investigation and Analysis on the Abnormal Increase of Dose Equivalent Rate around a Medical X-ray Diagnostic Room
    LI Jin-rong, Mo Su-fang, ZHANG Jing-bo, WANG Chang
    2017, 26(1): 31-33.
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    Objective To investigate the reason of abnormal increase of dose equivalent rate in one institution's medical X-ray diagnosis machine room in Guangzhou.Methods To collect the information of the X-ray diagnosis machine room, including radiological protection design、construction plan and drawings, etc and analyze by using occupational health survey method, combining with monitoring results of radiation around the room.Results The results of the occupational health survey showed that all shields surrounding machine room were in confomity with the requirements of the national standard. The reason of abnormal increase of the dose equivalent rate around the medical X-ray diagnosis machine room was the unreasonable setting of the machine room. The direction of X-ray directly leading to the location of room door.Conclusion It shoulal stengthen the implementation medical X-ray diagnosis of occupational hazard in the room radiation protection pre-assessment system, standardize the layout of machine room, set the installation of medical X-ray machine reasonably.
  • Analysis of Total α、β Radioactivity in Drinking Water of Guangxi Province
    HUANG lu-lu, MO Dasong, PAN Yang-chang, XIE An-jie, LIANG Yong, SU Yun-peng
    2017, 26(1): 36-38.
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    Objective To detect analyze the total α and total β activity of drinking water in Guangxi Zhuang Autonomous Region between 2011 and 2015 and master the radioactive level of drinking water in Guangxi.Methods The detection method of total α and total β radioactivity is in accordance with the national standard "standard test method for drinking water" (GB 5750.13-2006) method.Results The average content of total α and total β radioactivity was (26.95±56.53) mBq·L-1 and (135.33±194.88) mBq·L-1.Conclusion Guangxi region overall level of radioactivity in drinking is water is good condition and comply with national drinking water health standards.Among them, radioactivity in the south is the highest, followed by the east; northern and it is similar in the western and central regions, belonging to the normal background level. The intensity of development and utilization can be the increased.
  • Estimation of Dual-Source CT Effective Dose
    WANG Qiang, FU Qiang, LIN Lin, ZHU Jian-quan
    2017, 26(1): 41-44.
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    Objective To estimate dual-source CT effective doses under four different examination protocols.Methods After putting TLDs in the Alderson Radiation Therapy Phantom,we scanned the phantom under two different examination protocols.Then effective doses were calculated with the acquired absorbed doses of organs and tissues. Tissue weighting factors recommended by the ICRP were adopted in the calculation. Effective doses were also calculated using the AAPM recommended method by which the DLP was multiplied by the K factor.Results Effective doses under two different examination protocols were obtained.The effective doses were 3.66 and 2.98mSv respectively when phantom were used. The effective doses were 2.81 and 1.55 mSv respectively calculated using the K value recommended by AAPM and were all lower than that obtained using phantom.Conclusion Under the head scan mode,the absorbed dose of crystalline lens is high.Effective doses calculated using the method recommended by AAPM were lower than those using the Alderson Radiation Therapy Phantom.
  • Comparison and Analysis of the Dose Conversion Coefficients of External Photon Irradiation
    CHEN Chong, XIN Rui, YANG Xiang-shan, HE Qiang, FENG Wei, CHEN Da-wei
    2017, 26(1): 59-62.
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    Objective To explore and analyze the limitations of the dose conversion coefficients of the current national standard GBZ/T144-2002 external photon irradiation, in order to provide some reference for its update.Methods Compare the dose conversion coefficients of the national standard GBZ/T144-2002 with the International Commission on Radiological Protection (ICRP) 116 and analyze the differences.Results The overall change trends of the two dose conversion coefficients are consistent, however, the left lateral geometry of the liver radiation, dose conversion coefficients of the ICRP 116 for females and males are higher than GBZ/T144, when the energy is less than 150 keV, the relative changes can be more than 30%; in addition to the right lateral geometry, dose conversion coefficients of the ICRP 116 for females are higher than males; the energy from 30 keV to 200 keV, the relative changes of the left lateral geometry in radiation are more than 30%, the lower the energy, the greater the difference, the largest is more than 100%. The antero-posterior geometry radiation of the female breasts, the energy higher than 4 MeV, the relative changes are more than 50%.Conclusion Under different radiation conditions, the national standard is consistent with the results of ICRP 116, but when considering the type of reference phantom and reference persons' parameters, gender, secondary electron, incident photon energy and so on, the difference is obvious and the dose conversion coefficients of the GBZ/T144 need to make some adjustments.
  • Study on The Integrated Measurement Method of Radon Concentration in The Air of The National Control Point of The National Radiation Environment Quality
    LU Jian-feng, MA Yong-fu, ZHANG Rong-suo, XIAO De-tao, SHAN Jian, SONG Jian-feng
    2017, 26(1): 70-72.
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    Objective To monitor the long-term trend of the concentration of radon in the air of the national radiation environment quality control point. Methods Solid state nuclear track method was used in measurement, Radon concentration measurement data on different point position measurement are normalized. The influence of humidity, air pressure, high of 220Rn measurement results were analyzed. Results The measurement method was tested in standard radon laboratory, and the error of measurement results was 7.1%. Conclusion Solid state nuclear track method in the standard radon laboratory scale can be used in measurement of radon concentration in the air accumulation point.
  • The Application of Portable Electric Refrigeration HPGe Gamma Spectrometer in Radiation Monitoring
    LI Ze-shu, ZHOU Qiang, ZHANG Jing, LI Wen-hong, ZHANG Jian-feng, TUO Fei
    2017, 26(1): 82-85.
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    Objective To equip a new type of portable electric refrigeration HPGe gamma spectrometer system and applying it to the field of radiation monitoring. Methods Introducing the portable electric refrigeration HPGe gamma spectrometer system on the aspects of system structure and supporting, and calibrating the system in energy and efficiency. Results This system has the characteristics of portability, high intelligent, and good line energy. We obtained the accurate efficiency calibration curve, which makes radionuclide content in environmental samples analysis more quickly and accurately. Conclusion The portable HPGe gamma spectrometer system has a very good prospect for the application in radiation monitoring, and it can play an important role in the nuclear emergency monitoring.
  • Take Part in the National 2015 Personal dose Monitoring System for Radiation Workers Ability to Assess the Result Nnalysis
    CHEN Yu, XING Ya-fei, LIU Chao, ZHANG Yan-wei, DU Wen-xia, WANG Li
    2017, 26(1): 92-93.
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    Objective By participating in the 2015 annual national radiation workers personal dose detection system capability assesment, improve the lab personal dose detection technology, to ensure the accuracy and reliability of the monitoring data.Methods According to the 2015 annual radiological technology institutions detection capability assessment plan prepare 7 groups of thermoluminescence personal dosimeters, and radiated by standard source as requested. Measurement are done by the laboratory. The results are analyzed and statistics are done.Results 2015 HP(10) the average annual appraisal results dose range of 0.32 mSv~3.04 mSv, conventional true value of dose range of 0.32 mSv~2.98 mSv, |Pi| ≤ 0.1or less a single set of performance, comprehensive performance|B|+S ≤ 0.1 or less. The results are judged as excellent.Conclusion Lab personal dose monitoring equipment is stable, accurate and the measurement results are reliable.
  • The Elementary Analysis on Several Problems of Medical Accelerator Charging Auxiliary Circuit Design
    LUO Rui, DONG Fu-hua, TANG Yan-bing
    2017, 26(1): 96-99.
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    Objective To find out the principle and method of the design of charging auxiliary circuit of medical accelerators.Methods The method is mainly base on the physical principle and trying to avoid the complex mathematical formula in the analysis of waveform frequency and waveform source circuit.Results Through the use of critical damping circuit, complete the full adjustment of pulse modulator.Conclusion Through the analysis of the main factor of the circuit, the actual auxiliary circuit design and verification are consistent and obtained a good verification.
  • Clinical Observation of Oral and Retention Enema with Smecta in the Treatment of Acute Radiation Enteritis
    CHEN Feng, LI Quan-fu, JIN Gao-wa, ZHANG Hao-yang
    2017, 26(1): 105-107.
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    Objective To observe the efficacy of oral and retention enema with Smecta in the treatment of acute radiation enteritis.Methods A total of 57 patients with cervical cancer were randomized into oral group (n=30) and retention enema group with smecta (n=27).All the patients were treated with three- dimensional and intensity modulated radiotherapy in combination with cisplatin.The efficient and the mean duration of different levels of radiation enteritis treatment were compared.Results The efficiency of retention was significantly higher than that of the oral group in level 2 and above radiation enteritis (P<0.05).The treatment duration of retention group significantly was shorter than that of the oral group in all patients with radiation enteritis (P<0.05).Conclusion The treatment duration was shortened and efficiency was increased with retention enema with Smecta. Retention enema is recommended in patients with level 2 radiation enteritis and smecta oral administration may be combined.
  • Analysis of Clinical Value in the Diagnosis of Chronic Appencitis 72 h after the Barium Meal
    TAN Ping, SUN Xiao-rong
    2017, 26(1): 108-110.
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    Objective To analyze of the clinical value of barium meal 72 h examination in the diagnosis of appendicitis.Methods A retrospectince analysis was made of 28 patients with suspected chronic appendictis from July 2014 to October 2014 whom had been oprerated confirmed by surgery pathology.Results All patients underwent preoperative gastrointestinal barium meal and residual barium is visible on the appeadix area fromthe 72 h gastrointestinal film.Conclusion The gastrointestinal barium meal after 72 h review of clinical suspected diagnosis of chronic appendicitis has high clinical value.