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Objective To analyze the results of acceptance testing of 60 extraoral dental X-ray equipment in Beijing, China from 2021 to 2022, and understand the main types and performance parameters of newly installed extraoral dental X-ray machines in the clinical market of Beijing, as well as the level of installation and trial run of the whole machine by various manufacturers, and to summarize the problems found in acceptance testing for improving equipment testing. Methods Field acceptance testing and evaluation were carried out according to the Specification for Testing of Quality Control in Medical X-Ray Diagnostic Equipment (WS 76—2020). Results The overall qualified rate of 60 extraoral dental X-ray equipment was 98.33%. Under the same condition of the same tube voltage for one dental equipment, the maximum deviation of the tube voltage indicated by the two modes (panorama and skull) is 5.5%, and the maximum difference of the half-value layer of the useful beam is 1.22 mm Al. There is also a certain difference between the exposure time indicating deviation from the panorama and the skull, with a maximum difference of 75.51%. Conclusion Strengthening ex-factory quality control, installing, and debugging of equipment can basically guarantee the performance of newly installed equipment. In the testing process, it is critical to ensure the effective point of measurement of the dose detector located on the central axis of the primary beam.
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Objective To evaluate the radiation protection of “four-in-one” dental X-ray equipment and to investigate the safety interlock of the equipment by measuring the scattered radiation at the position of the patient during operation. Methods A cone-beam CT dental phantom was used to simulate the patient’s head. The intra-oral and extra-oral components of the “four-in-one” X-ray equipment were installed in a 5 m2 room. The scattered radiation at patient position was measured using a γ/X-ray survey meter, and the effects of intra-oral and extra-oral components were compared. Results For a 5 m2 room, when CBCT was exposed under typical conditions, the dose at the patient's position was 10.70 uSv/h when there was an intra-oral component and 10.60 uSv/h when there was no intraoral component. The intra-oral part did not affect the radiation dose at the patient's position. When the intra-oral component was exposed, the dose rate at the patient's position was 4.05-6.85 uSv/h, and the extra-oral part did not affect the scattered dose of the patient examined with intra-oral components. Conclusion The evaluation of radiation protection of new equipment must comprehensively consider radiation safety and equipment operation safety. The results of this study provide suggestions for clinical radiation protection supervision and evaluation of “four-in-one” dental X-ray equipment.
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Objective To investigate the status of quality control of dental X-ray equipment in Beijing Dongcheng District, to explore the problems involved in radiation protection. Methods 41 medical dental X-ray machines were detected in Beijing Dongcheng District in accordance with Specification for testing of quality control in dental X-ray equipment (WS 581—2017). Results The qualified rate was higher in imported machines (100%) than that in domestic machines (76.92%), the overall qualified rate was 92.68%. In performance detection, the qualified rates were 100% except for the deviation of loading time (92.68%) and tube voltage (95.12%). No leakage was detected in 41 dental institutes. Conclusion The overall status of dental X-ray machines was good in Beijing Dongcheng District. More attention was paid to shield protection than to quality control of dental X-ray machines. Therefore, health administration should take measures to strengthen advocation of WS 581—2017, and improve radiation protection through routine equipment performance test, supervision of X-ray protection and radiation health education.
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Abstract Introduction To analyze edge detection and optical contrast calculation of light field-indicators used in X-ray via automated- and observer-based methods, and comparison with current standard approaches, which do not give exact definition for light field edge determination. Methods Automated light sensor array was used to measure the penumbra zone of the edge in the standard X-ray equipment, while trained and naïve human observers were asked to mark the light field edge according to their own determination. Different interpretations of the contrast were then calculated and compared. Results In contrast to automated measurements of edge definition and detection, measurements by human observers showed large inter-observer variation independent of their training with X-ray equipment. Different contrast calculations considering the different edge definitions gave very different contrast values. Conclusion As the main conclusion, we propose a more exact edge definition of the X-ray light field, corresponding well to the average human observer's edge determination. The new edge definition method with automated systems would reduce human variability in edge determination. Such errors could potentially affect the approval of X-ray equipment, and also increase the radiation dose. The automated measurement based on human observers' edge definition and the corresponding contrast calculation may lead to a more precise light field calibration, which enables reduced irradiation doses on radiology patients.
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Objective By the modern manufacture regulation of original equipment manufacture(OEM),the quality of large scale X-ray equipment is ensured by means of assembling the purchased key components,such as high frequency and high voltage generators and X-TV systems,etc.Methods The technology of Programmable Logic Controller(PLC)was utilized to improve the reliability of X-ray examination table.Results The design of PLC-controlled X-ray examination table was used in the digital X-ray equipment yeas ago.The malfunction probability of mechanic parts was very low,whereas the electric circuit part was almost zero.Conclusion The practice of PLC improves the reliability and control level for X-ray equipment.
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Objective To improve X-ray equipment for better medical treatment by digitally transform normal X-ray equipment.Methods Digital image workstation was equipped for digital photography so that ordinary X-ray equipment has the function of a digital X-ray equipment.Results The digital transformation enhance the clinical performance of X-ray equipment.Conclusion It has been proved that some ordinary X-ray equipment can be equipped with digital workstation.
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PURPOSE: This study was to evaluate the beam quality of intraoral X-ray equipments used at Yonsei University Dental Hospital(YUDH) using the half value layer(HVL) and the characteristic curve of intraoral standard X-ray film. MATERIALS AND METHODS: The study was done using the intraoral X-ray equipments used at each clinical department at YUDH. Aluminum filter was used to determine the HVL. Intraoral standard film was used to get the characteristic curve of each intraoral X-ray equipment. RESULTS: Most of the HVLs of intraoral X-ray equipments were higher than the least recommended thickness, but the REX 601 model used at the operative dentistry department and the X-707 model used at the pediatric dentistry department had HVLs lower than the recommended thickness. The slopes of the characteristic curves of films taken using the PANPAS 601 model and REX 601 model at operative dentistry department, the X-70S model of prosthodontic dentistry department, and the REX 601 model at the student clinic were relatively low. CONCLUSION: HVL and the characteristic curve of X-ray film can be used to evaluate the beam quality of intraoral X-ray equipment. In order to get the best X-ray films with the least radiation exposure to patients and best diagnostic information in clinical dentistry, X-ray equipment should be managed in the planned and organized fashion.