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Objective The purpose of this study is to grasp the current situation of radiation protection in some non-medical institutions in Hangzhou, and to provide basis and reference for the relevant authorities departments to make the radioactive hazard factors monitoring plan for non-medical institutions. Methods The configuration of the personnel protective equipment and radiation level of radiation sources and radiation devices in 5 non-medical monitoring institutions in Hangzhou were investigated and analyzed by means of questionnaire survey and on-site detection. Results The radiation workers of 5 monitoring institutions have carried out personal dose monitoring, and their annual individual dose equivalent meets the requirements of relevant national standards. The ambient dose equivalent rates around the radiation source and radiation device room are lower than the minimum detection limit of the instrument. When the source is stored, the maximum ambient dose equivalent rates at 5 cm and 100 cm away from the external surface of the source container were 22.2 μSv/h and 2.0 μSv/h, respectively. When the source is in use, the maximum ambient dose equivalent rates at 5 cm and 100 cm away from the external surface of the source container were 44.3 μSv/h and 5.0 μSv/h, respectively. Conclusion Under normal operation, the radiation dose level of some non-medical monitoring institutions in Hangzhou is at a low level, while the ambient dose equivalent rates around the external surface of the source container is at a high level. Therefore, non-medical institutions should improve their awareness of radiation protection and strengthen radiation management.
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Objective To study the radiation level in the surrounding of patients undergoing 99Tcm-MDP SPECT bone imaging and associated influencing factors and provide experimental data for the radiation safety of personnel around the patients.Methods A total of 367 patients undergoing whole-body bone imaging in Cancer Hospital,Chinese Academy of Medical Sciences were investigated to measure the ambient dose equivalent rate around the patients at different time and different distances from the patients,analyze the variations of ambient dose equivalent rate with time and distances,estimate the dose level at different distances around the patients,and evaluate the radiation dose to personnel around the patients.Results The ambient dose equivalent rate around the patient decreased exponentially with time;the effective half-life of 99Tcm in patients' body increased with time.The ambient dose equivalent rate varied by power function with increasing distance within 4 meters from the patient with the mean power value of -1.45.The radiation levels were 238.3 μSv at 0.5 m,99.7 μSv at 1 m,and 61.8 μSv at 1.5 m from the patient undergoing 99Tcm injection to its vanishing in patients' body.At different time points,the radiation doses at 0.5 m off the patient for 10 min were:9.9,3.0,1.9 μSv at 0,3 and 6 h,respectively.Conclusions The ambient dose equivalent rate around the patients undergoing 99Tcm-MDP SPECT bone imaging decrease rapidly with increasing time and distance.The patients can cause a certain degree of exposures to the surrounding personnel,but the exposure level is far lower than the relevant national standards.It is suggested that the patients should not receive other types of diagnosis and treatments spending lot of time and in close contact with medical staff while bone imaging being conducted on the same day.
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Objective To develop the radiation shielding device for an environmental radiation survey meter with an aim to precisely measure local radiation levels and evaluate decontamination effectiveness in Fukushima.Methods A kind of lead alloy was selected as the main material for the shielding device.Attenuation effects of different lead plates and lead cylinders were measured at the radiation regulatory laboratory and in a polluted area of Fukushima,respectively.The whole shielding device was designed on the basis of measurement results,attenuation effects,cost of production and practicability.Results The whole device was composed of main shielding,probe shielding and a bracket with lid.The main shielding was a lead cylinder with 10 cm in height and 3 cm in thickness.The probe shielding was a lead cylinder with 8 cm in height and 2 cm in thickness.The thickness of lid was 1 cm.Conclusions The device can be available to effectively shield the influence of ambient radiation and accurately measure local radiation levels and evaluate decontamination effectiveness.It can play a valuable part in post-disaster reconstruction of contaminated areas in Fukushima.
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Objective The rapid development of radiation equipment has put forward higher requirements for protective facil -ities.The aim of this study was to research the radiation protection status of treatment equipment room in thirty -three medical units from East China area , and to put forward corresponding countermeasures to improve the level of radiation protection . Methods The li-cense and archival of X-ray machine, CT, gamma knife, accelerator, after loading therapy machine were surveyed in the thirty-three medical units .The engine room size , wall thickness , lead equivalent of protection doors , and leakage level of equipment were detec-ted.All the data were evaluated and analyzed on the basis of the corresponding national standards . Results ①The inspection pass rates of radiation treatment equipments in the first class hospitals were afterloader (100%), X-ray apparatus(99%), gastrointestinal machine(98%), CT(98%), medical processing accelerator (98%), gamma knife(97%), DSA(94%), PET-CT(94%), ECT (90%), dental engine(84%)and molybdenum target drone (84%).The inspection pass rates of radiation treatment equipments in other class hospitals were medical processing accelerator (100%), X-ray apparatus(91%), CT(89%), gastrointestinal machine (80%), DSA(80%) and (80%) gamma knife.②The qualified rates of the leakage radiation levels of radiation therapy , diagnostic radiology and nuclear medicine were 100%, 99% and 97%. Conclusion The radiation protection of treatment equipments and facilities in thirty-three medical units from East China area needs to be strengthened . We should strengthen supervision , implement the rules and regulations , strictly perform the regulation of radiation protection evalua-tion, and strengthen the training of radiation protection regulations and skills .
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Objective To study the effect on the environmental radioactivity level and the health of the residents in Shanghai when Qinshan Nuclear Power Station(QNPS) has been in normal operational condition for 17 years. Methods The field monitoring and the sampling analytical method were used for monitoring the radioactivity level in outdoor environment, drinking water, food and soil. Results The outdoor natural radiation level and the radioactivity level in the sample of the environmental media were on the normal background level. There was no distinct change in the environmental radiation level of Jinshan Area when QNPS was in normal operational condition. The radioactivity level in the environmental media was far lower than the limit values specified by the national standard GB. The effective dose of the outdoor natural external exposure for the residents is about 0.102 mSv/a and the effective dose of the internal exposure from the artificial radionuclides 90Sr and 137Cs in food for the residents is about 0.488 μSv/a. Conclusions There is no effect of the radioactive contamination on the environmental radioactivity level and the health of the residents in Shanghai when QNPS has been in normal operational condition for 17 years.