Table of Content

20 September 2014 Volume 34 Issue 5

  

A Trend Study on Radiodiagnosis and Radiotherapy and Radiological Protection for Medical Exposure in Shanghai

Zheng Junzheng, Gao Linfeng, Zhuo Weihai, Yao Jie, Wang Bin, Qian Aijun, Ji Guiyi, Xiao Hong

RADIATION PROTECTION. 2014, 34(5):  265-273. 

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This paper reviews the rapid development of various types of Radiodiagnosis and Radiotherapy in China and aboard, which leads to a dramatic increase of application frequency of medical exposure. Then summaries the trend found through the investigation on the medical exposure levels during the Eleventh Five-year Plan in Shanghai. According to the above analysis, suggestions to strengthen the medical exposure protection are proposed. When the X-ray diagnosis, interventional radiology, nuclear medicine and radiation oncology become indispensable means to modern medicine, the public exposure due to health examinations and disease diagnosis or treatments has been institutions undergoing X-ray diagnosis in Shanghai by the year of 2010, 2.1 more times of that in 1998. During this period, the total number of X-ray diagnosis equipment increased by 57.7%, and the number of X-CT scanners increased by 131.9%. The annual application frequency of X-ray diagnosis was 780.44 person·time for per 1 000 population in 2009. Compared with the data in 1996, the total frequency increased by 58.3%, and the frequency of X-CT scans increased 317.1%. In clinical nuclear medicine, compared with the data in 1996, the annual application frequencies increased by 139.4% and 210.6% for diagnosis and therapy in 2008, respectively. In the field of radiation oncology, the annual frequency also increased by 59.9% during the same period. Shanghai pioneered the survey on medical exposure levels during the Eleventh Five-Year Plan period in China, and has accumulated a lot of valuable new information and mastered the development trends of medical exposure. This work lays a solid foundation for effectively strengthening the radiation protection from medical exposure, provides a scientific basis for the rational planning and utilization of health care resources. Meanwhile, this work is also very useful for promoting the healthy development of radiology career while avoiding disadvantages and to the benefit of the people.

Application Frequency and Distribution of Medical Exposure from Diagnostic X-ray Procedures during 2006—2010 in Shanghai

Gao Linfeng, Zheng Junzheng, Zhuo Weihai, Yao Jie, Wang Bin, Qian Aijun, Ji Guiyi, Xiao Hong

RADIATION PROTECTION. 2014, 34(5):  274-280. 

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Through a comprehensive investigation on basic situations of diagnostic X-ray procedures in Shanghai, the types of diagnostic X-ray procedures and the gender and age of examinees were counted, and the application frequency and its distributions were calculated. At the end of 2010, there were 3 270 medical and health institutions in Shanghai, and 39.11% of them engaged in diagnostic X-ray examinations. The practicing physicians including assistants accounted 2.2 persons for per thousand population in the city. During the Eleventh Five-Year Plan period, the equipment numbers of digital radiography (DR), computed radiography (CR), mammography and digital subtraction angiography (DSA) increased by annual averages of 21.3%, 13.5%, 11.2% and 10.0% respectively. On the other hand, the equipment number of conventional X-ray machine reduced by an annual average of 8.1% during the same period. The annual application frequency of diagnostic X-ray procedures was averaged to be 763.23 person·time for per 1 000 population in 2007 and 2009. Among the procedures, the chest photography, X-CT scans, limbs and joints photography were the mostly performed. The frequencies of skull radiography, bariumenema, pelvis and hips photography reduced significantly, while the frequencies of spine photography, cholecystography, torso X-CT scans and panoramic dental radiography increased significantly. Among different groups of examinees, 56.66% of the group under 15-year old took the chest radiography,22.54% and 26.43% of the group between 16-and 40-year old took the chest radiography and chest fluoroscopy, and 32.19% and 17.09% of the group older than 40-year old took the chest radiography and X-CT scans, respectively. Obviously, the application frequency of medical diagnostic X-ray procedures in Shanghai during the Eleventh Five-Year Plan period has reached a record high, and taking effective measures to strengthen the radiation protection from medical exposureis currently a very important public health issue.

Investigation on the Application Status of Interventional Radiology in Shanghai

Yao Jie, Zheng Junzheng, Gao Linfeng, Zhuo Weihai, Wang Bin, Qian Aijun, Ji Guiyi, Xiao Hong

RADIATION PROTECTION. 2014, 34(5):  281-287. 

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As the interventional radiology (IVR) operations usually require the aid of X-ray fluoroscopy guidance, the radiation exposures to patients and medical staffs are significantly higher than those in other X-ray diagnostic procedures. Therefore, the current application status on IVR was emphasized in the survey on medical exposure in Shanghai during the Eleventh Five-year Plan period. The basic information surveyed on the IVR includes the levels of hospitals, numbers of medical staff and equipment, and the number of procedures, etc. Based on the opinions collected from a large number of clinicians, the IVR procedures in this study were divided into 7 categories with 25 items for statistifying its application frequency and distribution, and the radiation doses were also monitored. In 2009, a total of 61 hospitals in Shanghai carried out the IVR, and there were 89 sets of X-ray machines for performing the IVR. The total procedure of IVR in Shanghai in 2009 was 163 308. Among them, the cardiovascular interventions accounted for 56.96%, and followed by the neural, tumor, peripheral and non-vascular interventions, accounting for 26.64%, 10.70%, 2.57% and 2.51%, respectively. While the diagnostic interventions only accounted for 0.76 %. The annual application frequency of IVR had reached 8.50 person·time for per 1 000 population in Shanghai. It indicates that the IVR has been widely performed in clinical, and the protection for patients and medical staffs is becoming one of prominent focus of the current medical exposure. This survey accumulates a valuable basis for further strengthening the effective protection of IVR.

Wind Tunnel and Numerical Simulation of the Effects of Cooling Tower Plume on Pollutants Flow and Dispersion

Fan Dan, Yao Rentai, Guo Dongpeng, Guo Zhanjie

RADIATION PROTECTION. 2014, 34(5):  288-296. 

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Wind tunnel experiment and numerical simulation method was used to study the effects on regional flow field and plume diffusion in the case of a NPP cooling tower with or without thermal plume emission. The mean flow field and turbulent structure around the site area influenced by a cooling tower was introduced. Effects of thermal plume on plume concentration distribution, ground axis concentration and diffusion parameters were also investigated. Results show, by the impact of the cooling tower and thermal plume, wind speed on wind direction axis decreases significantly with double-speed loss area appears; the thermal plume is found enhancing pollutants dispersion, increasing spreading range, decreasing the maximum concentration and significantly enlarging the vertical diffusion; and the influence of the surrounding air flow and pollutant dispersion from a cooling tower closely relates to the relative position of the chimney and cooling tower. When the line connecting cooling tower and chimney parallels the wind direction, the influence is significant. Meanwhile, the impact of the thermal plume on pollutant dispersion is also related to the relative position of the releasing source and cooling tower.

Study on the Accurate Measurement Method of Radon Progeny Concentration

Abdumomin Kadir, Zhang Lei, Guo Qiuju

RADIATION PROTECTION. 2014, 34(5):  297-303. 

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Study on the accurate measurement method of radon progeny is essential for establishing measurement standards of radon progeny concentration and for verification of commercial radon progeny measuring devices and it is important for studying radon progeny behavior and environmental radon exposure assessments. In this paper, based on radon progeny measuring principles, a study was conducted about the development rules and trends of radon progeny measurement methods by reviewing the development history of radon progeny measurement and comparing some commonly used measuring methods. The comparison results indicate that for the accurate measurement, α spectroscopic method is better than gross α method; Multi-period counting and Least-square calculating method is better than traditional three-count of five count method. Multi-period and simultaneous counting of α plus β spectra and weighted least-square calculation might be the future of the accurate measurement of radon progeny.

Research on Ion Exchange Technology Used in Primary Loop of Nuclear Power Plant

Liu Dan, Liu Jie′an, Wang Xin, Lou Hui, Chen Bin, Weng Minghui

RADIATION PROTECTION. 2014, 34(5):  304-309. 

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Two of the most important performance indicators of ion exchange resin in NPP (operating exchange capacity and decontamination factor) were experimentally studied. Firstly, simulant samples were prepared using typical ions presented in primary coolant in NPP, including Cs⁺, Co²⁺, Sr²⁺, Ca²⁺, Li⁺, and etc., and then, experiments were performed with different resins and concentrations. Results indicate that: (1) the usable operating exchange capacity could reach 80% of total exchange capacity when the mass concentration of sample was at 10^-6 level, and the operating exchange capacity was increased along with the higher concentration of sample. (2) The cross-linkage had appreciable effect on operating exchange capacity. (3) Comparing with a single processing bed, multi-beds in series demonstrates an obvious increase indecontamination factor (DF) .

A Quasi-monodisperse Aerosol Generator Used in Radioactive Nanoparticle Simulation

Su Yongyang, Zhu Fengrong, Liu Longbo, Wei Guanyi, Li Zhiming, Zhou Guoqing, Zhang Zhihong, Yi Xiaowei

RADIATION PROTECTION. 2014, 34(5):  310-314. 

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An evaporation-condensation-type aerosol generator capable of producing quasi-monodisperse and high number concentration nanoparticles was developed. Using a calibrated Scanning Mobility Particle Sizer (SMPS), the generator performance under different operation conditions was evaluated by means of on-line monitoring of the size distributions of the generated nanoparticle. Results show that the size distributions of the generated nanoparticles agree well with lognormal distribution. The mode diameter is about 30 nm under proposed conditions. The geometric standard deviation is about 1.3, which means that the particles are quasi-monodisperse. The number concentration could achieve 10⁶ cm^-3 and the variation is less than 10%. The generator has advantages of low cost, reliable performance, and easy-to-use. It could fulfill the requirements for the simulation study on radioactive aerosol and filtration techniques development of nanoparticles.

Research and Development of a Self-checking Radon Box

Wang Pan, Yang Mingli, Zhang Wei, Huang Yinping

RADIATION PROTECTION. 2014, 34(5):  315-318. 

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To facilitate the self-correction to some radon meters, a small, low-cost radon box was developed. The volume of radon box with uranium as radon source is 20 L with an saturated concentration of radon up to 20.6 kBq/m³. Theoretical calculations and performance testing results show that the radon check box is feasible and cost efficient, with which radon concentration and radon exposure can be obtained simply through theoretical calculation. It is very suitable for self-correction of some radon measuring instruments.

Measurement of Natural Neutron Ambient Dose Equivalent Rate in Tibet Autonomous Region

Xu Yongjun, Liu Senlin, Wu Jianhua, Pang Hongchao, Wang Chuangao

RADIATION PROTECTION. 2014, 34(5):  319-323. 

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The natural neutron ambient dose equivalent rate was surveyed by using neutron ambient dose equivalent rate meter. According to the analyzing results, at the location with altitude range 2 000—5 000 m in Tibet autonomous region, the measured value of natural neutron ambient dose equivalent rate was higher than that at sea-level point and it would be 2 times larger when the altitude value increases 1 280 m, and the buildings could result in obvious shielding effect.

Analysis of Occupational Exposure Control in Overhauling of Low Concentration Boric Acid Solution Tank

Wang Zhibing, Zhou Xun, Li Zhonghua, Chen Hao, Xie Jiangshan, Gao Yunfei

RADIATION PROTECTION. 2014, 34(5):  324-329. 

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The low concentrated boric acid storage tank (LC-BAST) is a major equipment of boric solution storage system for WWER1000 PWR. It is used for the storage of the primary-loop boric solution. The maintenance of the tank causes many issues of radiation protection. In this paper, the practice and methods of occupational exposure control in the maintenance of the tank are introduced, mainly including the radiation risk analysis and the practice of radiation protection,and evaluating the protective effect during the maintenance .

Intercomparison of External Dose Measurements by Eight Entities of Jiangsu Province

Wang Wanping, Zhang Ruixue, Shen Leyuan, Gao Xiaofeng, Zhang Haiqian

RADIATION PROTECTION. 2014, 34(5):  330-332. 

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In Jiangsu province, eight agencies participated in the intercomparison of external dose measurement. In comparison of 160 thermoluminescent dosimeter, the results showed that only one group of blind sample 1 was abnormal. The relative deviation of other 7 groups compared to the standard dose of 1 mSv was -16%—1%. The relative deviation of blind sample 2 compared to the standard dose of 4 mSv was -18.5% to 3.25%.The results showed that the measurement of seven laboratories were satisfactory.

An Overview of High Level Liquid Waste Vitrification in the United States

Song Yuqian, Gao Zhen, Ji Toujie, Liu Weiping

RADIATION PROTECTION. 2014, 34(5):  333-336. 

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The inventory and characteristics of high level liquid waste, facility operation experiences and lessons of high level liquid waste vitrificaton learned in the United States are described in this paper. Enlightments are obtained through summary and are expected to provide references for the high level liquid waste vitrificaton in our country.