| Part one Analysis on the results of Personal Dose Monitoring of RadiationWorkers in Guangdong Medical unitsObject Along with the more and more widely application of ionizing radiation in the medical industry,especially the rapid development of radiation therapy and nuclear medicine technology in recent years,while bringing benefits to the public,but also leading to the inevitable result of additional doses burden to radiation workers.The article based on the research and analysis on personal dose monitoring data of radiotherapy and nuclear medicine staffs in Guangdong medical units in 2003-2012,to learn the personal dose level of that two types of radiation workers in the province,and to analyze the trends of personal dose level over the years,to conduct researches on the causes of over investigation level,to understand their personal protection status,to find out the problems or negative factors of workplace or personal protection that may exist,then to provide data and theoretical support for further strengthening protection to radiation staff of the province.Method Using thermoluminescent dosimeters(TLD)method to detect personal dose of radiotherapy department and nuclear medicine department staff in Guangdong medical units,and collecting personal dose monitoring data for statistical analysis in ten consecutive years of 2003-2012.TO analyze the total collective effective dose and per capita annual effective dose,collective effective dose and annual effective dose per capita of each year or each departments,the number distribution ratio and the effective dose distribution ratio of people that was over investigations level;analysis to variance was used to compare the annual effective dose of multiple samples in each year,to predict the trends of per capita annual effective dose of each year by linear regression equation,and to compare if the difference of the per capita annual effective dose between radiotherapy and nuclear medicine departments was significant by t test.Results 5420staffs were monitored in radiotherapy and nuclear medicine departments in 2003-2012,in which there was 4498 staffs in radiotherapy departments and 922 staffs in nuclear medicine departments;collective effective dose that actually measured is a total of 2.80 person· Sv in the ten years;of which radiotherapy department was 2.00 person · Sv and nuclear medicine departments was 0.80 person · Sv;the average annual per capita effective dose of ten-year was(0.52 ±0.11)mSv/year,fluctuations of annual per capita effective dose for each year was between(0.32?1.24)mSv/year,difference of the means was significant(F= 136.11,P<0.05),to conduct a linear regression trend forecast of per capita annual effective dose in the ten years,and the regression equation was significant(F=10.03,P<0.05),the equation regression coefficient was-0.083,and there was statistically significant(t=-3.167,P=0.01)?then we can consider an overall linear decline was showing of per capita annual effective dose in the ten years;the annual per capita effective dose of radiotherapy department staffs was(0.44 ± 0.09)mSv/year,fluctuations in each year was between(0.26?1.13)mSv/year,the annual per capita effective dose of nuclear medicine departments was(0.86±0.17)mSv/year,fluctuations in each year was between(0.59-2.50)mSv/year;in the ten years,there were three staffs exceeded the investigation level in radiotherapy department,the excessive rate was 0.07%,and four staffs in nuclear medicine departments,excessive rate was 0.43%,in which one of them exceeded radiation workers occupational exposure five-year averaged effective dose limit prescribed in GBZ128-2002;the collective effective dose distribution ratio of staff(SN5)is 0.028(0.08/2.80),there were more staff exceeded the investigation level in 2010,so the SR5 value is higher at the number of 0.113;distribution ratio of the number that exceeded the investigation level(NR5)was 0.001(7/5420).Conclusions The annual per capita effective dose of staff in radiation therapy and nuclear medicine departments in Guangdong medical units was at a lower level of personal dose monitoring data in an overall decade in 2003-2012,and showing the overall downward trend as the years went on,although there were still fluctuations occasionally,but the downward trend was significant.Its per capita annual effective dose was far less than the annual dose limit,the number of staff that exceeded investigation level was only one-thousandth,and was also at lower level in comparison with domestic counterparts.This shows that every Guangdong medical units are giving a high degree of attention to radiation workers personal dose monitoring work,the effect of the implementation of radiological protection work is good,and is also at a high level of protection to radiation workers,and then reduce the effects of radiation on the health of the staff down to the lower level.But if compared to the case of radiotherapy department,the situation of nuclear medicine department is still not optimistic,and the per capita annual effective dose of staff in that departments was significantly higher than radiation therapy department,cases of the exceeded investigate level are six times the level of radiotherapy departments,and even showing a situation that there was staff that exceeded the annual dose limit.This shows that protection of nuclear medicine staff is not only an emphasis,but also a difficulty,increasing training to this staff,enhancing their self-protection awareness is imperative;given the characteristics that an open radiology workplace of nuclear medicine department,so that a further strict design to the grading and zoning of workplace,formulating the requirements for storage and handling of radiopharmaceuticals,regularly removing the radioactive contamination,and the specification for radioactive waste disposal system is of very necessary.Part two Surveys and protection research on the ESD dose of patients using X-ray photography in Guangdong ProvinceObject Along with the rapid development of medical irradiation technology,the use of irradiation methods for diagnosing or treating disease's is growing more and more popular,particularly the use of X-rays for diagnosing disease,resulted in that diagnostic X-ray irradiation-induced medical exposure becoming the largest source of artificial ionizing radiation,and medical exposure has also become the increasing concerned problem of all sectors of society.The article was based on the scene investigation and analysis on the entrance surface dose(ESD)of patients using X-ray photography in Guangdong province,to understand the radiation dose level of commonly radiographic position of patients used X-ray photography for diagnosing in the province,to provide data support for radiation protection department of our country to develop a new diagnostic X-ray photography guidance level that adapts to medical radiation level in nowadays,and to provide a reliable scientific basis for the rational allocation and the use of medical resources for government departments;Particularly conducive to guide the correct and reasonable application of medical radiation,to make a reasonable reduction of subjects individual dose and the public groups dose caused by various radiation treatment,in order to strive to achieve avoiding disadvantages,and to achieve the purposes of improving the level of medical exposure protection and the quality of medical exposure,also to achieve a better promotion of development of radiation treatment cause.Method Using thermoluminescent dosimeters(TLD)method to investigate the ESD dose of patients.Stratified random sampled 1165 patients using X-ray diagnostic photography in 20 hospitals,including primary hospitals,secondary hospitals and tertiary hospitals,which were distributed in eight prefecture-level cities(Guangzhou,Shenzhen,Zhanjiang,Meizhou,Shantou,Zhaoqing,Yunfu,Qingyuan)of Guangdong Province to conduct on a scene investigation.To record and compare the radiation dose of 8 kinds of postures including chest anterior posterior,lateral(PA,LAT),abdominal anteroposterior(AP),pelvic anteroposterior(AP),lumbar anterior posterior,lateral(PA,LAT)and thoracic spine anterior posterior,lateral(PA,LAT)and etc.,with TLD dosimeters method,at the same time,to mark down the equipment parameters(kV,mAs,etc.)using in the survey as well as the patients' basic information(gender,age,weight,etc.)who being investigated,and then recovered TLD elements and calculated the entrance surface dose(ESD)of all radiographic position in patients.First to describe the basic situation of patients being investigated,then to analyze the mean and standard deviation,50%quantile dose,75%quantile dose of entrance surface dose of the 1165 patients,and to compare the differences of entrance surface dose in patients with multiple sample mean variance analysis among the different radiographic,different grade of hospital and different device types,finally to analyze the differences of the entrance surface dose in patients in the survey and the existing medical instruction standard recommended values of X-ray photography.Results Stratified random sample of 1165 patients using X-ray photography for disease diagnosis were investigated,the means of the entrance surface dose(ESD)of different radiographic position in patients fluctuates in(0.32?7.06)mGy/time,with a minimum of chest PA(0.32mGy/time),and a maximum of lumbar LAT(7.06mGy/time);75%quartile values of the entrance surface dose inpatients fluctuates in(0.34?12.47)mGy/time,with a minimum of chest PA(0.34mGy/time),and a maximum of thoracic LAT(12.47mGy/time);there is slightly different of the entrance surface dose in patients using different types of X-ray photography devices,the entrance surface dose in patients using the common X-ray photography fluctuates in(0.61?7.39)mGy/time,entrance surface dose in patient using digital X-ray photography fluctuates in(0.22?6.87)mGy/time;if Compare the entrance surface dose of radiographic position like chest PA,chest LAT,pelvic AP in patients using different X-ray device types,the entrance surface dose of who using common X-ray photography device is higher than who using digital X-ray photography device,and the difference is statistically significant(P<0.05).75%quantile values of entrance surface dose(ESD)in patients using different types of X-ray photography device is vary considerably,75%quantile values of entrance surface dose(ESD)levels of who using common X-ray photography device fluctuates in(0.83?22.35)mGy/time,and 75%quantile values of entrance surface dose(ESD)levels of who using digital X-ray photography device fluctuates in(0.26?9.75)mGy/time.There is different in the entrance surface dose in patients using X-ray photography from different levels of hospital,entrance surface dose in patients of different radiographic position from primary hospital fluctuates in(0.42?6.77)mGy/time,the entrance surface dose in patients of different radiographic position from secondary hospitals fluctuates in(0.39?8.32)mGy/time,the entrance surface dose in patients of different radiographic position from tertiary hospitals fluctuates in(0.10?4.85)mGy/time,the entrance surface dose in patients of chest PA,chest LAT,thoracic AP,abdomen AP,lumbar spine AP,LAT lumbar spine and etc.from different levels of the hospital is statistically significant(p<0.05),except the radiographic position of chest AP is primary hospital>secondary hospitals>tertiary hospitals,the others are secondary hospitals>primary hospital>tertiary hospitals.Conclusions From the survey results,in addition to the entrance surface dose(ESD)levels of radiographic position in thoracic AP,thoracic LAT in patients who using common X-ray photography is higher than the current standard recommended values in the survey,the entrance surface dose(ESD)levels of the remaining radiographic position in patients who using the X-ray photography is lower than the current standard recommended values,for all radiographic positions in the survey,entrance surface dose(ESD)level in patients is lower than irradiation dose investigated during the " Nine five plan".This shows that the performance of X-ray photography equipment and the protection to patients are higher than the previous in the province,that is because medical x-ray photography diagnostic equipment which is the most widely used and of the largest number,is increasingly and commonly to carry out systematically monitoring to instrument performance,so that it can achieve the purposes of both diagnostic and therapeutic by using the x-ray photography,and can simultaneously reducing radiation dose of both patients and radiation workers;for the primary hospitals which situation of equipment is poorer,should strengthen the maintenance of equipment and performance monitoring,and if the performance of the equipment is no longer applicable,then should accelerate its pace of upgrading.However,according to the survey,the entrance surface dose level in patient of all radiographic positions is still a certain gap if compared to results of research of domestic first-tier cities as well as the abroad cities,and the results of research are slightly different if compared with other provinces.The results shows that,no matter analysis on the mean or the 75%quantile values of the entrance surface dose in patients,DR is generally better than the common X-ray photography equipment in controlling dose in patients between the different types of X-ray photography equipment;this is a direct result of the tertiary hospitals that are basic equipped with DR machines is significantly better than the primary,secondary hospitals in controlling radiation dose of patients.This is,in another way,also showing that there is a certain imbalance on the distribution of health care resource in the province,more advanced,good performance equipment mostly distributes in tertiary hospitals in big cities,and for primary,secondary hospitals in the more backward rural,are generally equipped with instruments and equipment which are older and poorer performance.So to a certain extent,the survey on patients radiation dose can contribute to the configuration of national health resources,and narrow the differences between regions as much as possible. |
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