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RISS 인기검색어
- 검색키워드
- 저자 : Tzu-Chi Chan (검색결과 2 건)
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Tzu-Chi Chan,Yu Ping Hong,Jia-Hong Yu 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.9
The coordinate measuring machine (CMM) is one of the most widely used precision measurement machines in the machinery industry. In this study, the analysis and compensation of structural deformation in spatial coordinates effectively depicts the improvement of the spatial accuracy of the motion of a three-dimensional measuring machine in a measurement area. In addition to accuracy, it is also projected that the measurement can be carried out more efficiently. Therefore, the measurement speed of the CMM and dynamic characteristics of the structure are becoming increasingly important. Consequently, the measuring machine has better dynamic characteristics and meets high precision requirements. During measurement, the geometric errors generated by the machine are mainly because of its moving structure in the spatial position. In this study, the CMM is driven by aerostatic bearings; the boundary conditions and parameter settings of each component are established to obtain analysis results that are highly consistent with the actual machine characteristics. The finite element method is used as an analysis tool, including static deformation, modal, spectrum, and transient analyses. Because of the structural deformation and spatial geometric errors caused by the moving structure of the measuring machine, the relative deformation errors can be evaluated through the analysis of the spatial position error compensation to improve the measurement accuracy of the machine.
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Evaluation of Malignancy Risk of Ampullary Tumors Detected by Endoscopy Using 2-[18F]FDG PET/CT
Chuang Pei-Ju,Wang Hsiu-Po,Tien Yu-Wen,Chin Wei-Shan,Hsieh Min-Shu,Chen Chieh-Chang,Hong Tzu-Chan,Ko Chi-Lun,Wu Yen-Wen,Cheng Mei-Fang 대한영상의학회 2024 Korean Journal of Radiology Vol.25 No.3
Objective: We aimed to investigate whether 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (2-[18F]FDG PET/CT) can aid in evaluating the risk of malignancy in ampullary tumors detected by endoscopy. Materials and Methods: This single-center retrospective cohort study analyzed 155 patients (79 male, 76 female; mean age, 65.7 ± 12.7 years) receiving 2-[18F]FDG PET/CT for endoscopy-detected ampullary tumors 5–87 days (median, 7 days) after the diagnostic endoscopy between June 2007 and December 2020. The final diagnosis was made based on histopathological findings. The PET imaging parameters were compared with clinical data and endoscopic features. A model to predict the risk of malignancy, based on PET, endoscopy, and clinical findings, was generated and validated using multivariable logistic regression analysis and an additional bootstrapping method. The final model was compared with standard endoscopy for the diagnosis of ampullary cancer using the DeLong test. Results: The mean tumor size was 17.1 ± 7.7 mm. Sixty-four (41.3%) tumors were benign, and 91 (58.7%) were malignant. Univariable analysis found that ampullary neoplasms with a blood-pool corrected peak standardized uptake value in earlyphase scan (SUVe) ≥ 1.7 were more likely to be malignant (odds ratio [OR], 16.06; 95% confidence interval [CI], 7.13–36.18; P < 0.001). Multivariable analysis identified the presence of jaundice (adjusted OR [aOR], 4.89; 95% CI, 1.80–13.33; P = 0.002), malignant traits in endoscopy (aOR, 6.80; 95% CI, 2.41–19.20; P < 0.001), SUVe ≥ 1.7 in PET (aOR, 5.43; 95% CI, 2.00–14.72; P < 0.001), and PET-detected nodal disease (aOR, 5.03; 95% CI, 1.16–21.86; P = 0.041) as independent predictors of malignancy. The model combining these four factors predicted ampullary cancers better than endoscopic diagnosis alone (area under the curve [AUC] and 95% CI: 0.925 [0.874–0.956] vs. 0.815 [0.732–0.873], P < 0.001). The model demonstrated an AUC of 0.921 (95% CI, 0.816–0.967) in candidates for endoscopic papillectomy. Conclusion: Adding 2-[18F]FDG PET/CT to endoscopy can improve the diagnosis of ampullary cancer and may help refine therapeutic decision-making, particularly when contemplating endoscopic papillectomy.
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