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.

Objective We propose a low-dose CT reconstruction method using partial differential equation (PDE) denoising under high-dimensional constraints. Methods The projection data were mapped into a high-dimensional space to construct a high-dimensional representation of the data, which were updated by moving the points in the high-dimensional space. The data were denoised using partial differential equations and the CT image was reconstructed using the FBP algorithm. Results Compared with those by FBP, PWLS-QM and TGV-WLS methods, the relative root mean square error of the Shepp-Logan image reconstructed by the proposed method were reduced by 68.87％, 50.15％ and 27.36％, the structural similarity values were increased by 23.50％, 8.83％ and 1.62％, and the feature similarity values were increased by 17.30％, 2.71％ and 2.82％, respectively. For clinical image reconstruction, the proposed method, as compared with FBP, PWLS-QM and TGV-WLS methods, resulted in reduction of the relative root mean square error by 42.09％, 31.04％and 21.93％, increased the structural similarity values by 18.33％, 13.45％ and 4.63％, and increased the feature similarity values by 3.13％, 1.46％ and 1.10％, respectively. Conclusion The new method can effectively reduce the streak artifacts and noises while maintaining the spatial resolution in reconstructed low-dose CT images.

Objective We propose a low-dose CT reconstruction method using partial differential equation (PDE) denoising under high-dimensional constraints. Methods The projection data were mapped into a high-dimensional space to construct a high-dimensional representation of the data, which were updated by moving the points in the high-dimensional space. The data were denoised using partial differential equations and the CT image was reconstructed using the FBP algorithm. Results Compared with those by FBP, PWLS-QM and TGV-WLS methods, the relative root mean square error of the Shepp-Logan image reconstructed by the proposed method were reduced by 68.87％, 50.15％ and 27.36％, the structural similarity values were increased by 23.50％, 8.83％ and 1.62％, and the feature similarity values were increased by 17.30％, 2.71％ and 2.82％, respectively. For clinical image reconstruction, the proposed method, as compared with FBP, PWLS-QM and TGV-WLS methods, resulted in reduction of the relative root mean square error by 42.09％, 31.04％and 21.93％, increased the structural similarity values by 18.33％, 13.45％ and 4.63％, and increased the feature similarity values by 3.13％, 1.46％ and 1.10％, respectively. Conclusion The new method can effectively reduce the streak artifacts and noises while maintaining the spatial resolution in reconstructed low-dose CT images.

Cryoablation therapy with explicit anti-tumor mechanisms and histopathological manifestations has a long history.A large number of clinical practice has shown that cryoablation therapy is safe and effective,making it an ideal tumor treatment method in theory.Previously,its efficacy and clinical application were constrained by the limitations of refrigerants and refrigeration equipment.With the development of the new generation of cryoablation equipment represented by argon helium knives,significant progress has been made in refrigeration efficien-cy,ablation range,and precise temperature measurement,greatly promoting the progression of tumor cryoablation technology.This consensus systematically summarizes the mechanism of cryoablation technology,indications for oral mucosal melanoma(OMM)cryotherapy,clinical treatment process,adverse reactions and management,cryotherapy combination therapy,etc.,aiming to provide reference for carrying out the standardized cryoablation therapy of OMM.

Due to the complex anatomical structure of ankle and the various mechanisms of ankle injury, manyeponyms and systematic classifications of ankle fracture have been developed in the past centuries. Before the emergence and constant improvement of classifications of ankle fracture, ankle fractures were most commonly named afterthe physicians who first described them. Now,these ankle fracture eponyms are still found in medical literature, textbooks and even mass media. Many special named ankle fractures can be explained by the Lauge-Hansen classification now, and they may have little practical use. However, it is still necessary to summarize and review these ankle fracture eponyms, in order to correct the wrong usage of these and to remember the sages in this field.We reviewed both common and less frequently used ankle fracture eponyms, focusing on imaging features to identify and differentiate these injuries. We also briefly reviewed the mechanism of each injury, associated complications, its diagnosis and treatment.