Objective To evaluate the current status in the implementation of GBZ/T 201.5-2015 Radiation shielding requirements for radiotherapy rooms-Part 5: Radiotherapy room of proton accelerators, identify issues in the application of its technical indicators, and provide a basis for the in-depth implementation and further revision of the standard. Methods In accordance with the Standardization Law of the People’s Republic of China and the Guidelines for Health Standards Tracking Evaluation (WS/T 536-2017), a combination of cluster sampling and stratified sampling methods was employed to select professionals involved in proton accelerator radiotherapy devices and facilities in three provinces (or municipalities directly under the central government) as the subjects of the survey. A questionnaire was developed to collect basic information about the subjects and their understanding and application of the technical indicators in the standard. A standard evaluation indicator system with a total score of 100 points was established to score the implementation of the standard (40 points), the technical content (30 points), and the effectiveness of the implementation (30 points). Results A total of 169 professionals from 107 institutions participated in the survey, with 79.88% of the respondents having at least 5 years of experience in radiation therapy and 74.56% holding intermediate or higher professional titles. The score of standard implementation was 18.3 points. The awareness rate exceeded 80%, indicating a high level of awareness about the standard. However, the scores for the dissemination and application of the standard were relatively low, accounting for 28% and 32% of their respective full marks. The technical content of the standard and the effectiveness of its implementation scored 27.0 and 26.6 points, respectively. The overall score in the evaluation of standard implementation was 72 points, with scores of 68.6, 72.3, and 75.0 for Beijing City, Shanghai City, and Jiangsu Province, respectively. Conclusion GBZ/T 201.5-2015 Radiation shielding requirements for radiotherapy rooms-Part 5: Radiotherapy room of proton accelerators is scientific and operable, and it is well-coordinated with relevant laws and standards. However, considering the development in FLASH technology and multi-chamber radiotherapy room, it is necessary to revise and improve the standard.

Objective To track and evaluate the implementation and application of the occupational health standard Radiation shielding requirements for radiotherapy room—Part 4: Radiotherapy room of ²⁵²Cf neutron afterloading (GBZ/T 201.4-2015) by radiation health technical service agencies, medical institutions, health supervision agencies, and radiotherapy facility design units, and to provide a scientific basis for the further revision and implementation of this standard. Methods Following the Guideline for health standards tracking evaluation (WS/T 536-2017) and the project implementation plan, relevant practitioners were randomly selected for a questionnaire survey. The survey primarily focused on their awareness, standard training, application, and revision suggestions of GBZ/T 201.4-2015. The results were summarized and analyzed. Results A total of 168 evaluation questionnaires were collected from relevant practitioners in 28 provinces. Only 31.6% of the respondents reported being “well familiar” or “ familiar” with the standard, 27.4% of the respondents believed that the standard was widely used, and 45.2% of the respondents believed that the standard could meet the needs of their work. Only 14.9% of the respondents had received relevant training on the standard, more than half of the respondents had not applied the standard within the past 10 years, and 45.2% of the respondents believed that the standard "needs to be revised". Conclusion Due to the small number of californium-252 neutron afterloading radiotherapy devices in operation on the market, the overall awareness of the standard is low, suggesting that relevant authorities need to strengthen training and publicity of the standard, and that certain sections of the standard need to be revised or merged.

Objective To investigate the levels of radionuclides in food in Beijing, China, and assess the committed effective dose to local residents from food intake. Methods From 2021 to 2022, a total of 65 food samples across 7 categories were collected in Beijing. The activity concentrations of radionuclides, including ¹³⁷Cs, ²¹⁰Pb, ²³⁸U, ²²⁸Ra, ²²⁶Ra, ⁴⁰K, ⁹⁰Sr, ²¹⁰Po, ³H and ¹⁴C, were measured using gamma spectrometry and radiochemical methods. By combining the monitoring results with dietary consumption data of Beijing residents and the internal dose coefficients for Chinese reference adult phantom, the committed effective dose was estimated. Results The levels of radionuclides in food in Beijing were within the normal background range, consistent with related surveys in China and abroad, with activity concentrations below national standard limits. No significant differences were found in the activity concentrations of ¹³⁷Cs, ²³⁸U, ²²⁸Ra, ²²⁶Ra and ⁴⁰K between food samples collected from key areas and those from control areas (P > 0.05). The committed effective doses calculated according to internal dose coefficients for Chinese reference adult male phantom and GB 18871-2002 were 0.26 mSv and 0.19 mSv, respectively. Based on the Chinese reference adult male phantom, the majority of the committed effective dose was attributed to ²¹⁰Pb (45.1%), ²²⁸Ra (37.1%), ²¹⁰Po (12.3%), and ²²⁶Ra (4.7%). Conclusion The levels of radionuclides in food in Beijing fluctuated within the background range, resulting in a low radiation dose burden to the population.

Objective To explore the uranium concentration in surface water and drinking water in Beijing, China and the relationship between uranium concentration and gross α activity concentration. Methods Water samples were collected from 16 districts in Beijing. Uranium concentration and gross α activity concentration were measured with WGJ-III trace uranium analyzer and LB6008 six-channel α/β counter using the ultraviolet fluorescence and thick source methods. Results The uranium concentrations in surface water and drinking water were 1.131 and 1.572 μg/L, respectively. The gross α activity concentrations in surface water and drinking water were 0.059 and 0.074 Bq/L, respectively. There were no significant differences in uranium concentration and gross α activity concentration between surface water and drinking water (P > 0.05). The uranium concentration was positively correlated with the gross α activity concentration, with a correlation coefficient of 0.700 (P < 0.05). The gross α activity concentration was determined by the uranium concentration with a determination coefficient of 48%. The committed effective dose of ²³⁸U in drinking water was between 3.284 × 10⁻⁵ and 1.640 × 10⁻³ mSv, with an average value of 5.400 × 10⁻⁴ mSv. Conclusion The uranium concentration and gross α activity in the surface water and drinking water in Beijing fluctuate and remain in the background range. These values are much lower than the recommended limits of 0.03 mg/L and 0.5 Bq/L stipulated in the GB 5749-2021 Standard for Drinking Water Quality. The annual committed effective dose of ²³⁸U through drinking water ingestion is very small.

Objective To understand the effects of ²⁴¹Am standard material powder with different matrices on the determination of gross alpha activity in water, and to provide a reference for the selection and use of alpha standard sources. Methods The alpha counting efficiency of ²⁴¹Am standard material powder with different matrices was measured by low-background alpha and beta measuring instrument. The radiochemical recovery rate and whole process efficiency of gross alpha activity in water were determined by spike experiments. Results The alpha counting efficiency of the ²⁴¹Am standard material powder with four matrices was in the descending order of calcium carbonate, calcium carbonate and silica mixed matrix, calcium sulfate, and silica. The default chemical recovery rate is 1 when gross alpha activity in water is measured by thick source method. The use of ²⁴¹Am standard material with calcium carbonate as a matrix resulted in about 35% decrease in gross alpha activity, and about 10% deviation was observed using ²⁴¹Am standard material with silica or calcium carbonate and silica mixed matrices. The whole process efficiency of alpha activity in four spiked water samples with ²⁴¹Am standard solution and ²⁴¹Am standard material powder with calcium carbonate, silica, or mixed matrix was 6.34%-7.30%. Conclusion Standard materials with different matrices demonstrate different self-absorption of alpha particles and various influence on the chemical recovery. When purchasing and using standard material powders for alpha activity measurement in laboratories, the composition of the matrix should be clarified as much as possible, and the gross alpha activity in water should be determined by measuring the whole process efficiency if necessary.

Objective To investigate the method of tube furnace oxidation combustion and liquid scintillation counting for the determination of carbon-14 in seafood, and to provide technical support for the monitoring of carbon-14 in seafood. Methods By studying the pyrolysis characteristics of five types of dried seafood samples, including yellow croaker, white shrimp, swimming crab, clam, and seaweed, a temperature control program suitable for the oxidation combustion of seafood was established. The combustion efficiency, carbon element recovery rate, and the accuracy and precision of the method were determined. Results The combustion efficiency was more than 98% for most seafood using the recommended combustion program. The recovery rate of carbon was similar to that calculated by glucose combustion; both were more than 95%. Four laboratories validated the accuracy of the method by measuring the carbon-14 activity concentration in the Chinese sugar carbon standard material. The relative errors ranged from 1.03% to 3.41% and the average relative error was 2.36%. The precision of this method was verified by measuring the carbon-14 activity concentration in yellow croaker samples. The within-laboratory relative standard deviation ranged from 5.11% to 9.35% and the between-laboratories relative standard deviation was 4.04%. Conclusion The tube furnace oxidation combustion and liquid scintillation counting method was used to determine the activity concentration of carbon-14 in seafood. The recommended oxidation combustion program is more targeted and less time-consuming. The accuracy and precision of this method meet the requirements. This method is suitable for the determination of carbon-14 in seafood.

Background ¹³⁷Cs in atmospheric aerosol is the product of past nuclear weapon tests and nuclear accidents. When ¹³⁷Cs is released into the atmosphere, it will deposit in dry land and marine environment, causing pollution of soil surface, water, agricultural products, and animal byproducts, and affecting public health. Objective To identify the variation pattern of ¹³⁷Cs activity concentration in aerosol and its correlation with dust concentration in Beijing area from 2017 to 2020. Methods A total of 958 aerosol samples were collected from November 1, 2017 to June 30, 2020 in Beijing with a high volume air sampler at a sampling flow rate about 600 m³·h⁻¹ and a collection time for each sample about 24 h. The activity concentration of ¹³⁷Cs in the aerosol samples was determined with a low-background high-purity germanium γ spectrometer. The dust concentration was calculated using the difference in the mass of the aerosol filter before and after sampling. The detection rate of ¹³⁷Cs and dust concentration in different seasons were compared. Spearman rank correlation test was used to analyze the correlation between ¹³⁷Cs activity concentration and dust concentration. Results From 2017 to 2020, the ¹³⁷Cs activity concentrations of 33 from 958 aerosol samples in Beijing were above the minimum detectable activityconcentration, the overall detection rate of ¹³⁷Cs was 3.4%, and the activity concentration ranged from 1.86 to 45.53 μBq·m⁻³, with a median value of 4.85 μBq·m⁻³. The detection rate of ¹³⁷Cs was highest in spring, followed by autumn, and lowest in winter and summer (8.4%, 3.0%, 1.1%, and 0.5%, respectively). The dust concentration ranged from 0.03 to 1.55 mg·m⁻³, with an average value of 0.18 mg·m⁻³. There was a statistically significant difference in the dust concentrations in spring, summer, autumn, and winter (F=45.51, P<0.05), and the highest value was 0.24 mg·m⁻³ in spring (P<0.05). The ¹³⁷Cs activity concentration was positively correlated with the dust concentration (P<0.05). Conclusion The ¹³⁷Cs activity concentration in aerosol in Beijing from 2017 to 2020 fluctuates within the range of background level, and its activity concentration is highest in spring, followed autumn, and lowest in summer and winter.

Objective:To investigate the risk factors of diabetes mellitus complicated by pulmonary tuberculosis.Methods:The clinical data of 83 patients with diabetes mellitus complicated by pulmonary tuberculosis who received treatment in Taiyuan Fourth People's Hospital from March 2020 to March 2022 were collected. These patients were divided into sensitive group ( n = 45) and resistant group ( n = 38 ) according to the results of drug sensitivity test. Univariate and multivariate non-conditional logistic regression was performed to analyze the influential factors of drug resistance. Results:Univariate logistic regression results revealed that there were significant differences in blood CD4 +T lymphocyte count ( χ2 = 11.73, P = 0.001) and diabetic complications ( χ2 = 4.94, P = 0.026). Multivariate non-conditional logistic regression analysis was performed taking whether blood CD4 +T lymphocyte count was lower than the average level and whether patients with diabetes mellitus had complications as independent variables, and taking whether drug resistance was a dependent variable. The results showed that the OR (95% CI) value of the decreased blood CD4 +T lymphocyte count was 4.909 (1.926-12.514). It is a risk factor for drug resistance of diabetes mellitus complicated by pulmonary tuberculosis. Conclusion:The decrease of blood CD4 +T lymphocyte count is a risk factor of drug resistance in diabetes mellitus complicated by pulmonary tuberculosis, and it should be intervened early in the clinic.

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.

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 U_rel 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.