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Objective: To investigate the implementation of GBZ/T 201.3-2014 Radiation Shielding Specification for Radiotherapy Room--Part 3: Radiotherapy Room of γ-ray Sources (hereinafter referred to GBZ/T 201.3-2014). Methods: A total of 129 personnels, who were involved in the approval and supervision of radiation diagnosis and treatment construction projects in 19 provincial administrative agencies, engaged in radiation protection testing and evaluation of γ-ray radiotherapy rooms in radiation health technology service institutions, and used GBZ/T 201.3-2014 in other institutions (environmental impact assessment, education and scientific research), were selected as the participants using a stratified random sampling method. A questionnaire survey was conducted to assess their awareness and application of the standard. Results: The participants' awareness of GBZ/T 201.3-2014 was ≥63.6%, but the training rate was only 9.1% to 50.0%. The familiarity with the various chapters of the standard was over 86.4%. And 42.6% of the participants reported using the standard at least once a year. Regarding the applicability of the standard, all of the participants believed that the standard meets the needs of approval, supervision, testing, or evaluation, and adapts to the updated development of radiotherapy equipment and technology. And 94.6% of the participants believed that the use of the standard could improve the level of protection design and management, and 92.2% believed that the standard was widely applied. Regarding the adequacy of the standard, 97.7% of the participants believed that the standard's reference for ambient dose equivalent rate was reasonable, while 34.1% believed that the standard needs revision. Conclusion: The participants are satisfied with the standard and believe its applicability. They have a good level of awareness of the standard, but there is a room for improvement in their familiarity with the shielding calculation related content of the standard. The promotion, training, and practicality of the standard need to be strengthened.
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Objective To ensure the accuracy of gamma spectrometer in our laboratory for the analysis of radionuclides in samples and to improve the laboratory personnel’s ability to perform analyses of radionuclides. Methods Our laboratory had continuously participated in the national assessments of gamma spectrometry of radionuclides organized by the Chinese Center for Disease Control and Prevention. The samples were measured by a high-purity germanium gamma spectrometer (GEM-MX7080P4). An analysis was performed on the results of the gamma spectrometry assessments from 2014 to 2021. Results Our laboratory had an overall qualified rate of 100% (8/8) and an overall excellent rate of 39% (3/8) in the gamma spectrometry assessments from 2014 to 2021. The distribution ranges of RD, Z, U, and Urel for 28 measurements involving radionuclides 208Tl, 228Ac, 232Th, 40K, 238U, and 137Cs were −11.82% to 5.97%, −0.59 to 0.30, 0.02 to 0.92, and 4.33% to 10.49%, respectively. Conclusion The methods used in our laboratory for gamma spectrometry of radionuclides are accurate and the testing reports issued by our laboratory are reliable.
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Objective To investigate the awareness, implementation, and application of the Radiation Shielding Specification for Radiotherapy Room, Part 3: Radiotherapy Room of γ-Ray Sources (GBZ/T201.3—2014) by medical institution personnel, to collect problems and recommendations, and to provide a scientific basis for further amendments and implementation of the standard. Methods A questionnaire survey about the awareness, training and application situation and the modification advices of the standard was conducted among practitioners engaged in the production, use, and machine room design related to γ-ray source radiotherapy equipment (collectively referred to as medical institution personnel) in 12 provinces and direct-administered municipalities in China. The questionnaires were collected and a special Excel database was set up for statistical analysis using SPSS 22.0. Results A total of 126 practitioners responded and completed the questionnaire. Approximately 75.4% of respondents indicated that they either “understood” or “understood well” the standard; 42.86% received relevant training; 45.24% and 54.76% indicated that the standard “met” or “basically met” the requirements of detection of γ-ray radiotherapy equipment shielding or design of shielding room. The standard was highly evaluated for suitability. However, the awareness of the standard was inadequate, the rate of training participation was low, and its practical application was limited. Conclusion The standard generally aligns with the requirements for shielding room design in γ-ray radiotherapy. Some revisions should be done according to the current situation of γ-ray radiotherapy.
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Objective To investigate the awareness of the Radiation Shielding Requirements for Radiotherapy Room–Part 2: Radiotherapy Room of Electron Linear Accelerators (GBZ/T 201.2—2011) among relevant practitioners in medical institutions as well as its implementation and application situation and collect relevant problems and suggestions for an evaluation of the scientificalness, standardization, and timeliness of the standard, and to provide a scientific basis for the further revision and implementation of the standard. Methods An online questionnaire survey was conducted among relevant employees in medical institutions providing medical linear accelerator radiotherapy across 22 provinces of China, which investigated the awareness, training, application, and revision suggestions related to GBZ/T 201.2—2011. The questionnaires were collected and analyzed. Results A total of 340 relevant practitioners filled out the questionnaire. Of the participants, 66.80% were physicists; 79.11% had an awareness of the standard; 56.18% ever participated in the standard-related training; but the survey results showed that the practitioners did not have a good knowledge of the standard’s content, and the training and promotion were not enough; 83.24% thought that the standard had been widely used; 17.60% thought that the standard needed to be revised; 76.76% thought that there was a need to add calculation examples; 88.82% thought that neutron shielding needed to be considered for the 10 MV X-ray accelerator room. Conclusion The standard has been widely known in the field of radiotherapy protection. With the development of radiotherapy technology, the standard should be revised to add calculation examples and consider neutron shielding in the 10 MV X-ray accelerator room. The standard is highly technical and difficult to grasp, so the promotion and implementation goals should be appropriate for different personnel groups, the training for employees at key posts should be strengthened, and the methods recommended in the standard should be uniformly used throughout the country.
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Objective:To explore the present state of radiation protection in an operational large-sized irradiation facility and the distribution of incurred radiation doses in the controlled area under abnormal conditions, and to analyze the acompanied radiation risk.Methods:With an irradiation facility in operation as the research object, the radiation doses were measured using AT1121 X and gamma dose rate meters for the soruce both in working and storage. Thermoluminescent dosimeters (TLDs) were used to measure the dose distribution in an irradiation field under abnormal conditions. The radiation safety features were checked against the several relevant national standards, with the radiation risks evaluated.Results:The radiation dose rates were in the range of 0.09-0.11 μSv/h, lower than the environmental background level whether in storage or working. Under abnormal working conditions, the radiation dose values from high to low were 1.0-101.3 Sv, 32.7-514.0 mSv and 8.7-183.2 μSv in the irradiation field, respectively. At the outside maze, the doses were close to the background level.Conclusions:The protection features of the irradiation facility meet the requirements of the relevant national standards. Under abnormal conditions, radiation could cause serious damages to the persons staying in the irradiation field. These persons were suggested to access to maze as soon as possible to reduce the exposure time, and activate the emergency protection equipments to deescalate the 60Co source onto the well.
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Objective:To ascertain the distribution of interventional radiodiagnosis and treatment resources and the current situation of radiological protection in Beijing, standardize the interventional radiodiagnosis and treatment, and promote the implementation of radiation protection regulatory measures.Methods:Various medical institutions at differetn levels that perform interventional radiodiagnosis and treatment in Beijing were identified as the survey objects. With special questionnaires designed, the investigation groups at two levels of municipality and district was established to investigate the basic situation of interventional radiology and occupational health monitoring by the end of 2020. The indexes and parameters were analyzed and evaluated under the relevant national regulations and standards.Results:By the end of 2020, there were 93 medical institutions performing interventional radiology in Beijing, together with 236 digital subtraction angiography machines (DSA) with higher than 800 mA. A total of 135 593 cases of interventional radiological surgical operation were performed. There were 40 hospitals annually performing more than 1 000 cases and 41 hospitals perfoming 10-1 000 cases. There were 3 539 interventional radiological workers, with 99.0% holding radiological worker certificates. The passing rates of occupational health examination, personal dose monitoring and radiation protection training were 96.9%, 99.5% and 95.8%, respectively. A total of 3 532 sets of protective articles were provided for the workers, of which 98.9% were equipped with split or integrated lead clothing, but 6.5% were not equipped with lead protective glasses and 54.9% were not equipped with lead protective gloves.Conclusions:The radiation protection management for the interventional radiodiagnosis and treatment is generally good. However, the regulatory mechanism should be further improved based on the current distribution of interventional radiodiagnosis and treatment resources, with focus on strengthening the occupational health examination, the radiation protection training, and the configuration and use of protective equipment.
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Objective:To monitor and analyze the activity concentrations of 7Be and 210Pb in atmospheric aerosol in Beijing from 2017 to 2020. Methods:Totally 1 074 atmospheric aerosol samples were collected by high flow air sampler (SnowWhite) including 275 in spring, 266 in summer, 262 in autumn and 271 in winter and subjected to analysis by low background high-purity germanium gamma-ray spectrometery (ORTEC) to determine the activity concentrations of 7Be and 210Pb. Results:The activity concentrations of 7Be in atmospheric aerosol were from 0.56 to 14.84 mBq/m 3, with an avearage of 6.84 mBq/m 3, and from 0.01 to 9.37 mBq/m 3 for 210Pb, with an avearage 3.19 mBq/m 3. The differences in activity concentrations of 7Be and 210Pb in atmospheric aerosol among differernt seasons were statistically significant ( F=32.66, 93.93, P<0.05). Activity concentration of 7Be was highest in spring, followed by autumn, and lowest in summer and winter. Activity concentration of 210Pb ranged from winter, autumn, spring to summer in descending order. Conclusions:The activity concentrations of 7Be and 210Pb in atmospheric aerosol in Beijing from 2017 to 2020 fluctated within the range of normal level.
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Objective@#To study the output dose of external beam radiotherapy in Beijing and analyze the cause of output dose deviation. Guidance is given on the selection of measurement methods, calculation formulas and parameters.@*Methods@#During 2020, the output doses of medical electron accelerators, tomotherapy, cyberknife, and γ-knife were meas- ured based on the water absorbed dose calibration factor combined with the requirements in the IAEA TRS398 and TRS483 reports, and low-energy X-rays were measured based on the air kerma calibration factor combined with the requirements in the AAPM protocal. The output dose was measured and compared with the preset irradiation value.@*Results @#A total of 59 external beam radiation therapy equipments’s output dose were investigated.2 of the 49 accelerators’s absolute value of relative deviation between the system indication value and the measurement exceeded 3%; the deviation of other external beam radiotherapy equipments was less than 3%.@*Conclusion @#A unified method and multi-party quality control can ensure the accuracy of the output dose. In the routine operation of the equipment, the hospital should strictly implement periodic inspections to ensure accurate and reliable radiotherapy.
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Objective:To investigate radionuclide content in soil at 19 spots in Beijing, in order to provide scientific basis for the accurate evaluation of the levels of radioactive contamination.Methods:GEM-MX7080P4 HPGe γ spectrometer was used to analyse the activity concentrations of radionuclide 226Ra, 232Th, 40K and 137Cs in all 38 soil samples from 16 districts of Beijing from 2017 to 2018. Results:The mean activity concentration of 226Ra, 232Th and 40K were 23.9 and 24.1 Bq/kg, 31.2 and 31.7 Bq/kg, 600 and 578 Bq/kg respectively for the two consecutive years. The mean activity concentration of 137Cs in the two years was 1.21 Bq/kg, with the highest values of 5.48 and 6.18 Bq/kg, about 4.5 times and 5.1 times the average values in those years. Conclusions:All the result are within the range of the values from previous Beijing municipal and countrywide survey of environmental background, with 137Cs in soil arising almost from the previous nuclear activities or nuclear incidents.
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Since the accident on March 11th 2011 at the Fukushima Daiichi Nuclear Power Station following the Great East Japan Earthquake,huge amount of radionuclide has been released to the surrounding environment.In this study,the environmental monitoring method,γ-ray dose rates,radioactivity in environmental samples,food,wild animals and plants,health situation of residents were summarized.Through summarizing the accident experience of Fukushima Daiichi Nuclear Power Station,this research discussed and analyzed the accident combining with the situation in China.
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Objective To analyze the performance differences of CT scanners with different detector rows between different manufacturers,and to provide the basis for the rational allocation and use of these CT scanners.Methods According to the result from the sentinel surveillance in 2014,a total of 148 medical institutions were equipped with CT scanners in 16 districts of Beijing,including general hospital(53),cancer hospital(5),TCM hospitals(25),children′s hospitals(2),community hospitals(30)and other specialized medical institutions(33).According to the principle of simple random sampling,40 medical institutions are selected,including 14 general hospitals,1 cancer hospital,7 Chinese medicine hospitals,1 children′s hospital,8 community hospitals and 9 other specialized medical institutions.A total of 141 CT scanners are selected from all CT sets of the selected medical institutions from 2012 to 2014.According to GB 17589-2011 X-ray computed tomography device quality assurance testing status test,four parameters related closely to image quality were tested,including CT value(water),noise,high contrast resolution,and low contrast detectability.Results No significant differences were found in CT value(water),noise and low contrast detectability among CT scanners produced by different manufacturers(P＞0.05),whereas high contrast resolution was found to have a remarkable difference(χ2＝34.706,P＜0.05).Significant differences were found in noise,high contrast resolution and low resolution detectability between the CT scanners with ＜64 detector rows and ≥64 detector rows(χ2＝6.978,10.040,15.973,P＜0.05).However,there is no difference in CT value(water)(P＞0.05).For less-than-64 detector row CT scanners,no significant difference was found in CT value(water),noise and low contrast detectability among different manufacturers(P＞0.05).only high contrast resolution differed remarkably(χ2＝9.941,P＜0.05).For more-than-or equal-to-64 detector row CT scanners,CT value(water)and noise have no differences among different manufacturers(P ＞0.05),whereas,there were significant difference in high contrast resolution and low contrast detectability(χ2＝31.376,32.967,P＜0.05).Conclusions There were a few differences in the performance testing of CT scanners from different manufacturers,and the less-than-64 detector row CT scanners have advantages in noise and low contrast detectability compared with the more-than-64 detector row CT scanners,whereas the latter have advantages in high contrast resolution and scanning time,allowing its wider application in medical institutions with more special diseases.
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Objective To ascertain the dose levels to personnel from the activation products in the radiotherapy place of a proton acceterator and to provide technical basis for protection design of the treatment place and the personnel's radiation protection.Methods A PROTEUS 235 proton therapy system was analyzed for the potentials to produce activated nuclides in the air during its operation.The concentrations of the main radionuclides and the resultant personnel doses were estimated.Results The activity concentrations of activated nuclides were 15O 4.1 × 10-2,13N 3.3 × 10-2,41 Ar 6.2 × 10-3 and 11 C 2.0 × 10-2 Bq · cm-3,respectively,in proton accelerator hall,whereas those in the proton beam radiotherapy room were only about 5％ of the corresponding values in the proton accelerator hall.The annual doses to the radiation workers from immersion external exposure due to air activation were less than 1 and 0.1 mSv,respectively,when entering the proton accelerator hall 5 and 30 min after beam stopping;whereas those were 1.3-2.0,0.7-1.2 and 0.3-0.6 mSv,respectively,when entering the therapy hall 0,5 and 15 min after beam stopping.Conclusions The personnel doses received from activated nuclides in the air in the radiotherapy place of a proton acceterator are unignorable.The contribution to doses from immersed external exposure of 15O,13N,41Ar and 11C should be taken into full considerations,with necessary protection measures needed.
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Objective To explore the effect of radon released from water on the indoor radon activity concentration in groundwater supplies.Methods Two groundwater supplies in a city were chosen.Radon concentrations in three kinds of water samples were determined by using a continuous radon monitor with air-water exchanger,including source water,finished water and tap water.The solid track detector was used to analyze the indoor radon concentration in water supplies.Results The concentrations of radon in source water,finished water and tap water were (7.59 ± 1.36),(3.56 ±0.86),(3.68 ±0.81)Bq/L and (12.19 ±0.57),(7.87 ± 1.12),(9.50 t 1.12) Bq/L,respectively.The concentration of radon was the highest in source water and at less varying level in finished water and tap water.Aeration and filtration tank process significantly decreased radon activity in water.Radon concentrations in aeration and filtration rooms were 4 218 Bq/m3 and 1 937 Bq/m3,respectively,which exceeded the limit in work place (1 000 Bq/m3).Conclusions Aeration and filtration workplaces for groundwater supplies were found to contain elevated radon concentrations in air,which was released from groundwater.Radon issues in groundwater supplies in China should be paid more attention.
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Objective To understand the functional status and radiation protection requirements of helical tomotherapy (TOMO) unit when it is applied in clinic treatment so as to promote the construction of TOMO quality control system.Methods A helical tomotherapy unit with a type of tomotherapy Hi-Art was employed as the radiotherapy unit.A series of tests and analyses on dosimetric and radiation safety performance parameters of the TOMO unit were conducted with the use of a A1SL ionization chamber,a set of solid water equivalent phantoms and other test equipments.The performance parameters were compared with that of a conventional 6 MV accelerator with a type of ARTISTE.Results The deviations of static and dynamic output dose were-1.51％ and 1.18％,respectively.The values of PDD10/PDD1.5 and PDD20/PDD1.5 were 0.608 and 0.318 within the range of X-ray quality parameters calibration.Under the different field conditions of 40 cm × 5 cm,40 cm × 2.5 cm and 40 cm × 1 cm,the stability of transverse/longitudinal dose distribution curve was no more than 1.20％ and the offset distance of Jaw width was smaller than 0.5 mm.Radiation leakage ratio of the treatment rotating center from the muhileaf collimator (MLC) was 0.20％.No matter the average or the maximum value of the leakage radiation from couch plane was less than 0.02％.Conclusions The performances and testing requirements of TOMO unit are different from a conventional electron linear accelerator,the quality control index of TOMO unit should be set seperately and tested strictly in terms of the specific requirements of the unit by complying with the QC programme.The reliable quality control system should be established and effectively implemented to serve the radiotherapy quality and radiation safety effectively in the tomotherapy.
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Objective To investigate the radiation dose levels to the adults examined from diagnostic exposure in Beijing. Methods The radiation doses to the examined individuals were measured by using individual diagnostic radiology equipments in 30 random hospitals from a total of 10 districts and suburban areas, including 1 182 samples of X-ray photography,542 samples of mammography and 410 samples of CT examination. Results 2 134 samples were measured in this study. The dose ranges of X-ray photography, CR, and DR were 0?4 -24?1, 0?3 -13?9 and 0?1 -15?9 mGy, respectively. The average dose range of glandular breast was 0?3-5?4 mGy. In 410 CT samples the value of CTDIw , CTDIvol and DLP were 28?1 - 96?3 mGy, 7?0 - 23?4 mGy, and 162?2 - 898?1 mGy·cm, respectively. Conclusions Several dose levels from diagnostic examination were higher than guidance level for medical exposure in GB 18871-2002,which should be noted.
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OBJECTIVE@#To investigate the expression of SOX2 in laryngeal carcinoma and analyze the relation of SOX2 and clinical factors.@*METHOD@#We measured the expression of SOX2 protein in 45 laryngeal carcinoma fresh samples and 45 paracarcinoma tissues (cutting margin > 0.5 cm) with flow cytometer (Epics-XL II), 20 normal laryngeal mucosa samples were also studied as controls.@*RESULT@#The quantitative and qualitative expression of SOX2 protein in laryngeal carcinoma tissues was obviously higher than those in paracarcinoma and in normal laryngeal mucosa tissues respectively (P < 0 05). There was no significant difference between the expression of paracarcinoma and normal laryngeal mucosa tissues. In laryngeal carcinoma, the expression of SOX2 protein wasn't significantly related to patients' clinical classification, tumor size, smoking history, patients' age and sex but related to metastasis, pathological grade and clinical stage.@*CONCLUSION@#The high expression of SOX2 may contribute to the carcinogenesis and development of laryngeal carcinoma. It is an important index of judging metastasis and staging and prognosis of laryngeal carcinoma to measure the expression of SOX2 protein.
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Adult , Aged , Female , Humans , Male , Middle Aged , Biomarkers, Tumor , Metabolism , Carcinoma , Metabolism , Pathology , Flow Cytometry , Laryngeal Neoplasms , Metabolism , Pathology , Neoplasm Staging , SOXB1 Transcription Factors , MetabolismABSTRACT
Objective To study the radiation dose level and dose distribution of leakage and scattering radiation in a helical tomotherapy (TOMO) room,and to identify the dose distribution characteristic which is different from the conventional radiotherapy so as to provide scientific data for the radiation protection of TOMO.Methods A helical tomotherapy facility typed Tomotherapy Hi-Art was employed as the radiotherapy device.The air kerma from leakage radiation and scattering radiation distributed on the couch plane and in TOMO room were detected mainly by GR-200A TLDs of LiF(Mg,Cu,P),while 100 Gy were being accumulated under the condition of simulation radiation treatment.Then,the leakage radiation ratio and scattering-leakage radiation ratio (the ratio of site radiation dose to isocenter standard output dose) were calculated.Results The radiation level and dose distribution of leakage radiation and scattering radiation in the TOMO treatment room were in bilateral symmetry to the rotation isocenter and the treatment couch longitudinal axis,and the radiation level in front of the radiotherapy device was significantly higher than that of the rear of the TOMO equipment.In the plane of treatment couch,the maximum leakage radiation ratio at the position 100 cm away from the isocenter was only 1.3 × 10-4,and the mean value of the leakage radiation ratio at the position 300 cm away from the isocenter was lower than 2.0 × 10-5.The scattering radiation at 200-300 cm away from the isocenter was accounted for 25％-30％ of the leakage radiation from the responding sites,and the indoor scattering radiation decreased faster than leakage radiation with the distance from the isocenter.Conclusions The radiation level of leakage and scattering in a TOMO room is significantly lower than that in a conventional radiotherapy room.
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Objective To monitor the levels of radioactive contamination due to the Japanese Fukushima nuclear accident in Beijing,so as to provide scientific technical information for government to draw effective controlling strategy and processing mechanism.Methods The system of nuclear emergency nmonitoring was started,then the radioactive contamination levels of atmosphere,rain water,surface water and vegetables in Beijing were detected according to the relative survey regulations and technology criterions.Results During the period from 15 to 41 d after the accident,obvious radioactive contamination was found in the atmosphere of Beijing.The maximum radioactivity concentration of 131I ( 5.89 mBq/m3 ) was detected at 22 d after the accident.The radioactivity concentrations of 137Cs and 134Cs were surveyed forming their corresponding peaks at 20 d after the accident,but they were one magnitude lower than the peak value of 131I at least.In addition,the gross β radioactivity level in the water of Chao Bai-he river was verified to be in the range of 0.314 - 0.602 Bq/L. Conclusions The radioactive contamination due to Fukushima nuclear accident has not done visible harm to the public health in Beijing,but monitoring should be continued to observe the long-term effect of the accident.