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Absolute measurement of surface particle emission rates from α and β plane sources using a digitizer

Tianxiang LU ; Qianqian ZHOU ; Ming ZHANG ; Fei TUO ; Shuying KONG

Chinese Journal of Radiological Health.2023;32(1):1-5. doi:10.13491/j.issn.1004-714X.2023.01.001

Objective: To prove the validity and accuracy of the digitizer instead of the conventional electronics plug-in for radionuclide measurement. Methods: Based on a large-area flow-gas multi-wire proportional counter for 2πα and 2πβ surface particle emission rate measurement, the DT5730 digital waveform sampler developed by CAEN was used for waveform signal acquisition, amplitude analysis, and data processing of the α-plane source 241Am and the β-plane source nuclides 14C, 36Cl, and 90Sr-90Y of different energies. Results: The deviations between the α and β surface particle emission rate results obtained after dead time and background corrections and the measurements obtained based on the plug-in calibrator were all within 0.6%, within the uncertainty range, under consistent experimental conditions such as electronics threshold and high pressure. Conclusion The digitizer is an effective alternative to conventional electronics plug-ins for α and β signal acquisition and processing and the accurate measurement of α and β emission rates.

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Investigation of radioactivity level in an open-pit coal mine in Xinjiang, China and evaluation of personnel exposure dose

Huiping XU ; Yang ZHAO

Chinese Journal of Radiological Health.2023;32(1):6-9. doi:10.13491/j.issn.1004-714X.2023.01.002

Objective To investigate and analyze the levels of γ dose rate and radon concentration at all sites in a large open-pit coal mine with radioactivity that had been mined for many years in Xinjiang, China, and to estimate the effective dose exposed to the personnel. Methods A portable γ dose-rate instrument FH40G was used for fixed-point monitoring of the mining area, and a continuous radon detector was used for 24 h continuous monitoring of radon concentration level in the site. The personnel exposure dose was estimated according to the measured γ dose rate and radon concentration. Results In this open-pit coal mine, the range of γ dose rate was 51.4-435.8 nGy/h; the mean 24 h radon concentration was 15-25 Bq/m³; the range of annual effective dose to the personnel was 0.29-1.29 mSv/a. Conclusion According to the results of the survey, radon concentration levels at all sites are low, and no remedial action is required. The personnel exposure dose at most of the sites is far below the standard requirements, and some protective measures need to be taken in some areas of the dump.

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Analysis of quality control and protection level test results of medical electron linear accelerators in Shanghai, China

Zhou JIANG ; Jie YAO ; Linfeng GAO ; Shunqi LU ; Weiye YUAN

Chinese Journal of Radiological Health.2023;32(1):10-14. doi:10.13491/j.issn.1004-714X.2023.01.003

Objective To investigate the quality control and protection level of medical electron linear accelerators in Shanghai, China. Methods The startified random sampling method was used to cover tertiary, secondary and ungraded hospitals, and a total of 30 medical electron linear accelerators in 15 hospitals were tested for quality control and protection level according to relevant standards. Results Five medical electron linear accelerators failed the quality control test, with an overall inspection pass rate of 83.3% and a re-inspection pass rate of 100%. The pass rate of flatness of square X-ray irradiation field (5 cm × 5 cm)-(30 cm × 30 cm) was 83.3%, the pass rate of symmetry of square X-ray irradiation field was 96.7%, and other indices were qualified. All medical electron linear accelerator rooms passed the protection test. Conclusion The protection of medical electron linear accelerator rooms in Shanghai meets the requirements of national standards, and some indices do not meet the requirements of national standards in the preliminary inspection. The quality control of medical electron linear accelerators should be further strengthened to ensure the treatment effect of patients.

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Terrestrial gamma radiation level around Shidaowan nuclear power plant, China and influencing factors

Chenyang QI ; Wei ZHANG ; Xianpeng ZHANG ; Yi LIU ; Zhihui FENG

Chinese Journal of Radiological Health.2023;32(1):15-20. doi:10.13491/j.issn.1004-714X.2023.01.004

Objective To monitor the cumulative terrestrial γ radiation dose around Shidaowan nuclear power plant, Shandong, China before operation, to analyze the dose levels and influencing factors, and to estimate the annual effective dose to local residents. Methods Fifty-six monitoring sites were selected within 30 km around the nuclear power plant. The environmental γ radiation dose was measured by the thermoluminescence dosimeter monitoring method. The γ radiation dose levels were investigated for 369 days in four monitoring periods (January 16 to April 14, April 15 to July 20, July 21 to October 21, 2021, and October 22, 2021 to January 20, 2022 for periods I to IV, respectively). Relations between γ radiation and monitoring time, altitude, distance from the nuclear power plant were analyzed, and the annual effective dose of terrestrial γ radiation to residents was estimated to reflect the background terrestrial γ radiation level in the area. Results The average values of terrestrial γ radiation dose rate in the four monitoring periods in the area were (76.196 ± 3.366), (81.773 ± 6.144), (93.554 ± 7.449), and (97.604 ± 9.396) nGy/h, respectively, and the terrestrial γ radiation dose rate in the whole year was (87.282 ± 6.589) nGy/h. The effective dose to residents was 0.428 mSv. The terrestrial γ radiation level was high from July 2021 to January 2022. There was no significant difference in the γ radiation dose rate at the monitoring sites with different distance from the nuclear power plant. No impact upon the terrestrial γ radiation dose by the altitude was observed in this study. Conclusion The terrestrial γ radiation level around Shidaowan nuclear power plant in 2021 was at the background level.

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Analysis of results of national personal dose monitoring ability assessment in China, 2018—2020

Qianqian DONG ; Hongmei JIANG ; Xinghui ZHANG ; Qianou YE ; Ying ZHANG

Chinese Journal of Radiological Health.2023;32(1):21-25. doi:10.13491/j.issn.1004-714X.2023.01.005

Objective To determine the effectiveness of quality control measures in the laboratory by participating in the national personal dose monitoring ability assessment, and to improve personal dose monitoring ability and quality. Methods According to the requirements of the National Personal Dose Monitoring Ability Assessment Program and standards, seven groups of personal dosimeter were prepared and irradiated by accurate radiation source as requested, and the dose was measured by the laboratory participating in the assessment. The data were processed, and the uncertainty of the measurement results was evaluated. Results In 2018, the assessment results H_p (10) dose range was 0.68-4.27 mSv, the single group performance deviation was −0.01 to −0.06, and the comprehensive performance deviation was 0.04, and the result was qualified. In 2019, the assessment results H_p (10) dose range was 0.74-8.06 mSv, the single group performance deviation was 0.00 to −0.08, and the comprehensive performance deviation was 0.04, and the result was qualified. In 2020, the assessment results H_p(10) dose range was 0.83-3.93 mSv, the single group performance deviation was −0.01 to −0.10, and the comprehensive performance deviation was 0.06, and the result was excellent. Conclusion The personal dose monitoring system in our laboratory runs smoothly, and the monitoring results are accurate and reliable. The laboratory can issue test reports that meet the requirements of national standards.

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Investigation and analysis of indoor radon concentration of urban residents in Shiyan, China

Pei LI ; Wenshan ZHOU ; Fang WANG ; Liangliang GUO ; Shaohua YANG ; Tongqiang ZHAO ; Jiabing WU ; Rongbin SUN

Chinese Journal of Radiological Health.2023;32(1):26-29. doi:10.13491/j.issn.1004-714X.2023.01.006

Objective To monitor the indoor radon concentration of urban residents in Shiyan, China, and to analyze the related influencing factors. Methods From April to July, 2019, RSKS standard detectors were used to measure the indoor radon concentration of 125 households in Shiyan, and the results were analyzed. Results The indoor radon concentration of residents in Shiyan showed a skewed distribution, ranging from 13.8 to 145 Bq/m³, and M (P₂₅,P₇₅) was 38.3 (29.0,62.0) Bq/m³. The estimated annual effective dose of radon and radon daughters from inhalation was 0.52-5.50 mSv, and M (P₂₅,P₇₅) was 1.45 (1.10, 2.36) mSv, which was consistent with literature. Building structure (H = 14.10, P < 0.001), floor (H = 24.41, P < 0.001), and geographical region (H = 8.963, P < 0.05) were influencing factors of indoor radon concentration, and the differences were significant. Conclusion The indoor radon concentration of urban residents in Shiyan is lower than the national standard limit. However, in daily life, it is still necessary to take appropriate measures to reduce the concentration of indoor radon as much as possible.

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An analysis of occupational health examination results of 450 radiation workers in a steel mill

Jianwu HOU ; Youzhong ZHANG ; Xuesong MAO ; Dianjun HOU ; Ya MA

Chinese Journal of Radiological Health.2023;32(1):30-34. doi:10.13491/j.issn.1004-714X.2023.01.007

Objective To investigate the occupational health status of 450 radiation workers in a steel mill when they resigned, and to provide references and suggestions for the occupational health monitoring of the enterprise employees and for the workers’ proper arrangement after their resignations. Methods Occupational health examinations were performedon 450 steel workers who were about to resign in accordance with the applicable laws and regulations. And the examination results were statistically analyzed. Results Among the 450 radiation workers, 82% had abnormal examination results which included chromosome aberration in peripheral blood lymphocytes (4.89%), lens opacity (44.44%), pinguecula (25.33%), hypertension (28.22%), thyroid dysfunction (9.59%), and abnormal liver ultrasound findings (30.89%). Compared with the normal population, these steel workers had a significantly higher chromosome aberration rate in peripheral blood lymphocytes and a significantly higher incidence rate of ocular disorders. Conclusion It is important to effectively manage the occupational health of radiation employees in steel mills, and to regularly provide training on occupational health protection. To avoid radiation damage, workers should pay close attention to radiation protection at work, especially eye protection, to avoid eye disorders.

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Influence of 4D CT-based respiratory signal acquisition methods on delineation of moving tumor targets

Qianqian LIU ; Shengyu YAO ; Xuming CHEN ; Lingtong HOU ; Zhekai HU

Chinese Journal of Radiological Health.2023;32(1):35-39. doi:10.13491/j.issn.1004-714X.2023.01.008

Objective To compare the effects of different respiratory signal acquisition methods on the delineation of moving tumor targets. Methods A cube phantom containing a sphere was placed on a motion platform to simulate respiratory movement by setting motion period, frequency, and direction. Respiratory signal was acquired by real-time position management (RPM) method and GE method independently. Target delineation was conducted using the maximum intensity projection (MIP) sequence. The difference between the reconstructed volume and the theoretical moving volume was compared under the two respiratory signal acquisition methods for cube and sphere targets. Results Under the same respiratory signal acquisition method, the same respiratory amplitude, and different respiratory frequencies, reconstructed volume changes were relatively small. For the sphere target, the deviation between the reconstructed volume and the theoretical moving volume was −1.5% to 5.7% with the RPM method and −1.3% to −13.8% with the GE method (both P < 0.05). For the cube target, the deviation between the reconstructed volume and the theoretical moving volume was 0.2% to 0.9% with the RPM method and −2.6% to 0.9% with the GE method, with no statistical significance. Conclusion For small-volume sphere targets, the target volumes obtained from MIP images by the two respiratory signal acquisition methods are both smaller than the actual moving volume. For large-volume cube targets, there is no significant difference between the reconstructed and theoretical results with any respiratory signal acquisition method. The RPM method produces smaller deviation and better image quality when reconstructing small-volume targets.

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Clinical application of optical surface monitoring system in radiotherapy after radical mastectomy for left breast cancer

Bei KUANG ; Zhongqiang LIU ; Hui WANG ; Zhenming WU ; Xiqu YE ; Gengxian LIN

Chinese Journal of Radiological Health.2023;32(1):40-45. doi:10.13491/j.issn.1004-714X.2023.01.009

Objective To study the setup error under deep inspiration breath hold (DIBH) guided by optical surface monitoring system (OSMS) and free breathing (FB) FB1 and FB2 (without OSMS guidance, directly set up the body marker line by laser lamp) in radiotherapy after radical mastectomy for left breast cancer, and to provide a basis for individualized clinical target volume-planning target volume (CTV-PTV) expansion for the doctor in charge to delineate the target volume. Methods A total of 36 patients with left breast cancer after radical mastectomy were selected and divided into three groups, in which cone beam computed tomography (CBCT) images were taken in three states: DIBH, FB1, and FB2, respectively. CBCT and CT images were analyzed for registration; the absolute error data of linear displacement in the ventro-dorsal, cranio-caudal, and left-right directions were recorded, and the expanding margin was calculated. Results The translation errors in the ventro-dorsal, cranio-caudal, and left-right directions were (0.06 ± 0.22) cm, (0.05 ± 0.23) cm, and (0.01 ± 0.24) cm in the DIBH group, (0.07 ± 0.21) cm, (0.02 ± 0.23) cm, and (0.02 ± 0.21) cm in the FB1 group, and (0.07 ± 0.24) cm, (0.07 ± 0.34) cm, and (0.25 ± 0.09) cm in the FB2 group. The statistical results of the DIBH group and FB1 group in the ventro-dorsal, RTN, and ROLL directions were significantly different (P < 0.05). The statistical results of the FB1 group and FB2 group in the ventro-dorsal direction were significantly different. The relation of three groups in the value of margin of planning target volume was DIBH < FB1 < FB2 in the ventro-dorsal and cranio-caudal directions and FB1 < DIBH < FB2 in the left-right direction. Conclusion OSMS-guided DIBH radiotherapy in patients with left breast cancer after radical mastectomy can reduce the setup error and provide an important basis for individualized CTV-PTV expansion for the doctor in charge to delineate the target volume.

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Outcomes and prognostic factors of differentiated thyroid cancer with bone metastasis

Yan WANG ; Rong ZHENG ; Rong FAN ; Lin LIN ; Jianhua GENG

Chinese Journal of Radiological Health.2023;32(1):46-51. doi:10.13491/j.issn.1004-714X.2023.01.010

Objective To investigate the outcomes and prognostic factors of differentiated thyroid cancer (DTC) with bone metastasis. Methods A retrospective study was conducted on 108 DTC patients with bone metastasis who were treated in the Cancer Hospital of Chinese Academy of Medical Sciences. Kaplan-Meier survival curves were generated. Log-rank test and Cox proportional hazards model were used to screen the prognostic factors. The correlation between treatment and prognosis was analyzed. Results The median overall survival was 70 months. The 5-, 10-, 15-, and 20-year overall survival rates were 54.4%, 24.3%, 9.8%, and 4.3%, respectively. Univariate analysis showed improved prognosis in patients with single bone metastasis, without skeletal-relatedevents (SREs), and without cervical lymph node metastasis (P = 0.003-0.019). Patients who received combined treatments (P < 0.001) or ¹³¹I treatment alone (P = 0.109) showed better prognosis than those without ¹³¹I treatment. Multivariate analysis identified single bone metastases, SREs, and treatmentas independent prognostic factors. Conclusion In DTC patients with bone metastasis, good prognosis is significantly associated with single bone metastases, absence of SREs, and ¹³¹I therapy in combination with other therapeutic approaches.

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