Nuclear weapon tests and nuclear leakage accidents have resulted in worldwide contamination by radionuclides, and ¹³⁷Cs persists in the environment because of its long half-life. Due to their radionuclide-enrichment properties, wild edible mushrooms take up ¹³⁷Cs from the surrounding matrix and store it in their fruiting bodies, thus becoming an indicator medium for radionuclide contamination and can be used to evaluate soil contamination with radionuclides. However, there are large variations in ¹³⁷Cs activity concentrations in different wild edible mushrooms depending on regions, species, and lifestyles. Therefore, it is important to carry out the detection of ¹³⁷Cs in wild edible mushrooms to understand the mechanisms of ¹³⁷Cs transfer distribution and enrichment and to monitor the environment. This paper reviews the studies on ¹³⁷Cs in wild edible mushrooms in recent years both in China and other countries. This article analyses the content of ¹³⁷Cs in wild edible mushrooms in different regions, the transfer process from soil to wild edible mushroom fruiting bodies, and the distribution of ¹³⁷Cs in wild edible mushrooms. These results provide theoretical support for the future monitoring of radionuclides in wild edible mushrooms on a nationwide scale, the establishment of relevant databases, and in-depth research on the mechanism of radionuclide transfer.

Objective To determine the content and distribution characteristics of the artificial radionuclide ¹³⁷Cs and the natural radionuclides ²¹⁰Pb, ²²⁶Ra, ²²⁸Ra, and ⁴⁰K in wild edible fungi, and calculate the committed effective dose due to ¹³⁷Cs and ²¹⁰Pb in wild edible fungi. Methods Thirty samples of wild edible fungi were collected and their caps and stems were separated. A total of 60 samples were measured for ¹³⁷Cs, ²¹⁰Pb, ²²⁶Ra, ²²⁸Ra, and ⁴⁰K using a BE5030 wide-energy, low-background, high-purity germanium γ spectrometer. The paired analysis of the four radionuclides ²²⁶Ra, ²¹⁰Pb, ¹³⁷Cs, and ⁴⁰K was performed using SPSS 11.5. Results Among the 60 samples, the detection rates and dry weight specific activity ranges of ¹³⁷Cs, ²¹⁰Pb, ²²⁶Ra, ²²⁸Ra, and ⁴⁰K were 97% and 0.62-384 Bq/kg, 73% and 6.4-159 Bq/kg, 52% and 0.7-28.8 Bq/kg, 5% and 0.43-2.18 Bq/kg and 100% and （77.4-264) × 10 Bq/kg, respectively. Conclusion Based on the analysis of the 60 samples, the detection rate of radionuclides is in the order of ⁴⁰K, ¹³⁷Cs, ²¹⁰Pb, ²²⁶Ra, and ²²⁸Ra. In terms of the specific activity, the distribution of ⁴⁰K and ²²⁶Ra in wild edible fungi in the same region is basically uniform, while the content of ²¹⁰Pb and ¹³⁷Cs fluctuates in different samples. Although ¹³⁷Cs and ²¹⁰Pb can be detected in most of the wild edible fungi, the annual committed effective dose due to ingestion of wild edible fungi is negligible.

Objective:To investigate the relationship between artificial radionuclide 137Cs and stable cesium (Cs) in wild edible fungi and seek potential correlations. Methods:A total of 30 samples, including the caps (with gills) and stipes of wild edible fungi, were collected from the northeastern region of China. The measurement and analysis of 137Cs were conducted following recommended procedures in GB/T 16145-2022, and stable Cs was determined using inductively coupled plasma mass spectrometry (ICP-MS). Then, the correlation analysis of data on 137Cs and stable Cs was performed using SPSS 11.5 software, and scatter plots were prepared using the Origin 21.0 software. Results:The fungi caps exhibited a specific activity of 137Cs ranging from 0.52 to 55.9 Bq/kg (dry weight) and a stable Cs content from 0.069 mg/kg to 16.2 mg/kg (dry weight). The stipes showed a specific activity of 137Cs ranging from 0.53 Bq/kg to 101 Bq/kg (dry weight) and a stable Cs content from 0.075 to 11.5 mg/kg (dry weight). These data revealed a significant correlation between the specific activity of 137Cs and the stable cesium content in all samples including caps and stipes, with correlation coefficients r of 0.956, 0.912, and 0.931, respectively, and all significant levels P < 0.01. The ratios of the specific activity of 137Cs to stable Cs content varied from 2.09 Bq/kg to 20.1 Bq/kg (dry weight), with an average of 10.7 Bq/kg (dry weight). Conclusions:Wild edible fungi fail to distinguish between 137Cs and stable cesium when absorbing Cs elements from their growing substrates. Furthermore, there is a strong correlation between the specific activity of 137Cs and stable Cs content. In the case of exogenous 137Cs contamination, the ratio of the specific activity of 137Cs and stable Cs content will significantly change. Therefore, an increase in the ratio can be used as a reference for identifying 137Cs contamination events.

Objective:To explore the applicability of critical statistical measures Z, Z′, Zeta ( ζ), and En value in comparative capability assessments by analyzing the data from nationwide radiological health technology institutions from 2020 to 2023, aiming to provide a reference for further improving China′s comparative assessment method for verifying the γ-ray spectroscopy capability of radionuclides. Methods:Based on the nationwide analysis and comparison of γ-ray spectroscopy of radionuclides conducted annually by the National Institute for Radiological Protection, China CDC, the deviations between laboratory result and reference values were determined using the above-mentioned four statistical measures. Finally, the qualification rates of the γ-ray spectroscopy result from relevant institutions were assessed and analyzed.Results:The result indicate that the qualification rates of the Z value exceeded 85%, which might be inaccurate in some cases since it ignored the limitation of uncertainty. In contrast, the Z′ value yielded more scientific and representative result because it considered the uncertainty of reference values, and the inter-laboratory comparison qualification rate is above 95%. In the case of low uncertainty of the γ-ray spectroscopy result, the Zeta ( ζ) or En ratio exhibited relatively high sensitivity and, accordingly, relatively low qualification rates, indicating that this ratio may not comprehensively reflect the interlaboratory comparison result. Conclusions:The Z, Z′, Zeta ( ζ), and En values demonstrate their own advantages and limitations in assessing the capability of the γ-ray spectroscopy of radionuclides. For comparison projects involving multiple laboratories and complex measurement conditions, such as the nationwide verification of the capabilities of the γ-ray spectroscopy of radionuclides, it is feasible to combine the Z′ value with the Zeta ( ζ) or En ratio, with the former and the latter used to determine the qualified and excellent capability result, respectively. This enables the comprehensive assessment of the measurement and analysis capabilities of the γ-ray spectroscopy laboratories of radiological health technology institutions in China.

Objective:To understand the activity concentrations of varying chemical forms of 131I in nuclear medicine workplaces and assess the internal irradiation doses of 131I to workers. Methods:A high-volume air sampler was used for air sampling of 131I. Glass fiber filters, activated carbon filters, and iodine cartridges, which were connected in series, were employed to collect aerosol iodine, gaseous inorganic iodine, and gaseous organic iodine, respectively. A method for analyzing the activity of 131I unevenly distributed in the iodine cartridge was developed, and an HPGe γ spectrometer was used to determine the activity of 131I in samples collected from the nuclear medicine workplaces of 15 hospitals. Results:The concentrations of aerosol iodine, inorganic iodine, and organic iodine in 15 hospitals were determined at 0.19-206.67, 0.27-138.45, and 2.35-3 821.11 Bq/m 3, respectively, with arithmetic means of 22.04, 12.79 and 365.08 Bq/m 3, respectively. The maximum annual committed effective doses of varied forms of 131I inhaled by workers were determined at 0.19, 0.19, and 3.81 mSv, respectively, with a maximum total committed effective dose of 4.13 mSv. Conclusions:Gaseous organic iodine is identified as the primary form of 131I in the air within nuclear medicine workplaces. Therefore, it is necessary to highlight the monitoring and protection of gaseous organic iodine.

Objective:To establish a highly-sensitive method for the rapid measurement of 137Cs in seawater with an view to its preliminary application in eight coastal provinces of China. Methods:The method employed nickel potassium polyacrylonitrile (KNiFC-PAN), an organic polymer-based ion exchanged resin material, to filter and adsorb 137Cs from seawater at a rate of 60 ml/min via a peristaltic pump. The adsorption efficiency of KNiFC-PAN was determined by measuring the cesium ion concentration before and after adsorption in seawater, with the addition of stable cesium, using inductively coupled plasma mass spectrometry (ICP-MS). Three KNiFC-PAN matrix components of 137Cs standard samples were prepared for the efficiency calibration of well type high purity germanium gamma spectrometer to obtain its detection efficiency. Results:The established measuring method can complete the filtration and adsorption of 137Cs from 20 L seawater within 6-8 h, which was twice as fast as the co-precipitation method with phosphomolybdic acid-ammonium molybdate taking more than 12 h, as stipulated in the GB/T 16145-2022 standard. The cesium recovery rate was as high as 98.02%. The relative standard deviation of the efficiency calibration result for the three prepared standard samples was 1.30%, and the detection limit for 137Cs was 0.26 Bq/m 3. The activity concentrations of 137Cs in offcoast seawater in eight coastal provinces of China were detected ranging from 0.38 to 1.24 Bq/m 3. The activity concentration of 137Cs in coastal seawater of China was at the background level, while as reported in 2019 was 0.03-1.92 Bq/m 3 in the eastern Chinese seas and 1-2 Bq/m 3 in the Pacific Ocean. Conclusions:This method has high detection sensitivity and can quickly obtain the values of activity concentration of 137Cs in seawater, thus providing a rapid and feasible method for emergency monitoring of 137Cs in China.

Individual monitoring of occupational exposure consists of individual monitoring of external exposure and individual monitoring of internal exposure. In the early years, due to limitations in objective conditions, the implementation of internal exposure monitoring for radiation workers was relatively rare. Since 2018, the "Monitoring of Occupational Radiation Diseases Project" has supported provinces in successively conducting 131I measurements for nuclear medicine workers, and remarkable progress has been made. This paper analyzed and summarized the development of internal exposure monitoring for nuclear medicine in China in recent years and puts forward recommendations for future work.

Objective:To investigate the number of medical institutions and staff involved in 131I diagnosis and therapy in China, and to ascertain the level of 131I activity incorporated in thyroid of medical staff performing the 131I treatment. Methods:Questionnaires were used to investigate the basic information on nuclear medicine practices in all the non-military hospitals in China. Portable gamma spectrometers were used to determine and analyze the 131I activity in thyroid of the medical staff in some radioiodine treatment workplaces. The result were reported through National Radiological Health Information Platform. Results:Until December 2022, there had been 959 hospitals performing clinical nuclear medicine practices in China, with a total of 10 820 medical staff. In China, there have been 623 hospitals performing 131I therapeutical procedures, accounting for 65.0% of all nuclear medicine hospitals, and 333 hospitals performing 131I treatment of thyroid cancer, accounting for 34.7%. The hospitals equipped with automated radiopharmaceutical dispenser accounted for 61.3% of the 623 hospitals. A total of 2 210 nuclear medicine staff were monitored for internal exposure in 20 provinces in 2022, with 249 (11.3%) having activities above 100 Bq and the maximum value of 2.9 × 10 4 Bq. A total of 426 nuclear medicine staff in four provinces were detected using HPGe detectors, with 101 (23.7%) detected to have 131I in their thyroid glands. A total of 1 748 in 17 provinces were detected using NaI or LaBr detectors, with 379 (21.2%) detected to have 131I in their thyroid glands. The detection rate of 131I in the staff was found to increase with the increased amount of 131I purchased by hospitals. The detection rate of 131I in the hosptitals having purchased the amount of 131I≥3.70 × 10 6 MBq in 2021 was 32.1%. This value was notably higher than in the other three groups whose purchased amount <3.70 × 10 6 MBq, with a statistically significant difference( χ2=15.46, P < 0.001). Conclusions:There were great differences in the number of both hospitals and staff performing 131I treatment between different provinces in China. About one fifth of the staff in the 131I treatment workplaces could be detected to have incorporated 131I in their thyroid glands.

Radiation health testing is one of the important basic work of radiation health. In order to strengthen the quality control of radiation health testing, various provinces have successively established radiation health quality control centers since 2009, which have played an important role in the standardization and normalization of radiation health testing. National policies and sustained incentives from various provinces will accelerate the construction of radiation health testing and quality control centers. It will improve the level of radiation health technology by competency validation for radiation health testing.