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Objective To investigate radiation doses to examinees undergoing computed tomography (CT) scanning of different body parts (the head, chest, and abdomen) in medical institutions of Shijiazhuang, China, and to provide a reference for optimizing radiation protection for examinees in medical institutions. Methods March 2021 to March 2022, eleven medical institutions of radiation monitoring in Shijiazhuang were surveyed for the basic information, scanning parameters, and dosimetric data of a total of 930 adults and children who received CT examinations. The dosimetric data of the subjects were analyzed and compared with the domestic and international diagnostic reference levels and the results of other cities in China. Results In the above hospitals, the CTDIvol(P50) of CT subjects in children's group were 17.42-50.45 mGy, 2.13-14.01 mGy and 3.58-28.20 mGy, respectively. DLP(P50) ranges from 228.87 to 966.97 mGy·cm, 33.20 to 296.03 mGy·cm, and 74.90 to 926.53 mGy·cm, respectively. In the adult group, the CTDIvol(P50) in the head, chest and abdomen of CT subjects were 37.28-54.05 mGy, 6.43-14.99 mGy and 8.28-18.75 mGy, respectively. DLP(P50) ranges from 372.81 to 630.56 mGy·cm, from 219.77 to 467.93 mGy·cm, and from 313.86 to 689.87 mGy·cm, respectively. The distribution of radiation doses in different-grade hospitals varied greatly. The abdomen dose of the children's hospital was higher than other hospitals. Especially the primary hospitals were significantly higher than the recommended diagnostic reference level (DRL). Conclusion In some secondary and primary hospitals, the setting of CT scanning parameters was simplified, not specific to the subjects’ age and body types. They should strictly comply with the principal of optimizing radiation protection to strengthen radiation dose optimization and supervision, reducing the radiation dose of examinees in future examinations .
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Objective To investigate the application of radiological diagnosis and treatment equipment and distribution of medical radiation levels in medical institutions at various levels in Shijiazhuang, China in 2019, and to lay a sound foundation for further radiation protection and management. Methods A universally designed questionnaire was used to investigate and compile data on the level of the sampled hospitals, the number of radiation workers, equipment information, the number of outpatients and emergency patients, the number of inpatients, and the frequency of radiological diagnosis and treatment; the application frequency of each radiological diagnosis and treatment item was calculated based on the demographic data of Shijiazhuang. Results In Shijiazhuang, there were 390 medical institutions (excluding dental clinics) certified for radiological diagnosis and treatment, with a total of 4262 radiation workers and 1215 radiological diagnosis and treatment devices; 1.11 radiological diagnosis and treatment devices were available per 10 000 people, and 3.89 radiation workers were available per 10 000 people. The number of annual outpatients and emergency patients was 30 208 471, the number of inpatients was 1 981 295, and the total number of people or times receiving radiological diagnosis and treatment was 5 987 230. The application frequency of medical radiation was 546.70 persons/times per 1000 people, with the highest frequency for X-ray diagnosis (534.63 persons/times per 1000 people), followed by diagnosis and treatment with nuclear medicine (6.16 persons/times per 1000 people), and the lowest frequency for radiotherapy (1.17 persons/times per 1000 people). In terms of regional distribution, the highest frequency of medical radiation fell in Yuhua District (1602.97 persons/times per 1000 people), and the lowest frequency fell in Shenze County (203.21 persons/times per 1000 people). Conclusion The development of medical radiation is imbalanced in Shijiazhuang, with high-quality medical resources concentrated mainly in the main urban area, thus resulting in long-term overworking of hospital staff and equipment in some areas. The government and health administration departments should strengthen macro-control and the rational allocation of medical resources; medical institutions at various levels should rationally use radiological diagnosis and treatment equipment, strengthen judgments on the justness of radiation, and strengthen the training of radiation workers on protection knowledge and radiation protection optimization.
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@#<b>Objective</b> To investigate the current situation of quality control in medical linear accelerators in Hebei Province, China. <b>Methods</b> The main performance indices of some medical linear accelerators in Hebei Province, 2019—2021 were tested according to the current relevant effective standards GB 15213—2016 <i>Medical Electron Accelerators-Functional Performance Characteristics and Test Methods</i> and WS 674—2020 <i>Specification for Testing of Quality Control in Medical Linear Accelerator</i>. <b>Results</b> A total of 175 medical linear accelerators were tested from 2019 to 2021, and the annual pass rates were 72.4% in 2019, 75.9% in 2020, and 79.4% in 2021. The overall pass rate of initial inspection was 76.0%, and the pass rate of reinspection was 100.0%. The index with the lowest pass rate in the initial inspection was square X radiation field uniformity, followed by dose deviation and square X radiation field symmetry. <b>Conclusion</b> Medical institutions should strengthen quality control management, conduct regular testing of medical linear accelerators, and timely correct dose deviation, so as to ensure the treatment effect of patients.
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Objective To investigate the impact of metal plate on radiation dose distribution in surrounding tissues in cadaver specimens.Methods Stainless steel plate, titanium plate, and muscle strip were implanted into the left thigh of a corpse, respectively.All the specimens were irradiated with 6 MV X-ray , SSD = 100 cm.The absorbed dose of surface was measured by thermoluminiscent elements.Results Surface dose distributions differed significantly among the three different materials (F = 57.35, P < 0.01),with the amounts of 1.18 Gy ± 0.04 Gy (stainless steel plate), 1.12 Gy ± 0.04 Gy (titanium plate) and 0.97 Gy ±0.03 Gy (muscle strip), respectively.The surface absorbed doses on incident plane of stainless steel plate and titanium plate were significantly increased by 21.65% and 15.46% respectively as compared with that of muscle strip.The absorbed doses on the exit surface of stainless steel plate, titanium plate and muscle strip were 0.87 Gy ± 0.03 Gy, 0.90 Gy ± 0.02 Gy and 0.95 Gy ± 0.04 Gy, respectively (F =13.37, P <0.01).The doses on the exit surface of stainless steel plate and titanium plate were significantly lowered by 8.42% and 5.26% when compared with that of muscle strip.Using treatment planning system,the differences between dose distribution with and without metal plate were compared.Within 1 cm away from the incident plate, there was an obvious increase in the absorbed dose, while the influence was less than 5% 1cm outside the surface.The effect of dose distribution on exit surface was less than 2%.Conclusions The influence of metal plate on the radiotherapy dose distribution is significant.The deviations ranges from 5% to 29%.Under the same condition, the impact of stainless steel plate is much more than that of titanium alloy plate.