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Objective:To study the influence of intensive magnet fields on radiation dose measurement, and to demonstrate the feasibility of measuring magnet field correction factor by a combination of medical linac with variable magnet fields in view of needing for accurate measurement of the doses from reference beam arising in MR image-guided radiotherapy.Methods:A photon radiation field and a variable field with 6 MV nominal high voltage were produced by using conventional medical electron linear accelerator equipped with a pair of electromagnets with magnetic field strength up to 1.5 T. Both PTW30013 and PTW31010 ionization chambers were used to test the responses of ionization chambers under different magnetic field strengths at four orientations in which the angles between ionization chamber axis and magnetic field direction were 0°, 180°, 90° and 270°, respectively. The magnetic factors, kB, M was calculated and compared with the reported values in literature. Results:The response of ionization chamber was proportional to the magnetic field strength before it reached to a peak around 1 T, and then fell down as the magnetic field continued to rise. When the magnetic field was 0.35 T, the magnetic factors of PTW31010 were 0.988 2±0.000 3 and 0.997 4±0.000 4 corresponding to 90° and 0° directions, the discrepancy between 0° scenario and literature was 0.05% ± 0.04%. When the magnetic field reached 1.5 T, the magnetic factor of PTW30013 was 0.958 9±0.000 5 at the situation of 90°, which was 0.60% ± 0.05% different from the literature value.Conclusions:Conventional 6 MV medical accelerator equipped with electromagnet can be used to measure the magnetic field factor of reference dosimetry for MRIgRT.
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Objective:To study the effect of preoperative transcatheter arterial chemoembolization (TACE) on postoperative complications after hepatectomy in patients with hepatocellular carcinoma (HCC) by propensity score matching analysis.Methods:Of 1 666 patients with HCC undergoing hepatectomy in Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology and Tianyou Hospital of Wuhan University of Science and Technology from March 2015 to March 2021 were retrospectively screened. Of 262 patients were enrolled, including 236 males and 26 females, aged (50.3±11.8) years. Of 131 patients were enrolled in both the single surgery group and the combined group (preoperative TACE + surgical resection). Factors affecting the complications after hepatectomy in patients with HCC were analyzed using univariate and multivariate logistic regression method.Results:After matching the propensity score, the incidence of postoperative complications in the single surgery group was 22.1% (29/131), lower than that in the combined group [41.2% (54/131), χ 2=11.02, P<0.001]. The incidence of bile leakage in the single surgery group [2.3% (3/131)] was also lower than that in the combined group [(9.2% (12/131), χ 2=5.73, P=0.017]. Multivariate logistic regression analysis showed that the combined group ( OR=2.43, 95% CI: 1.28-4.61, P=0.007) had an increased incidence of postoperative complications, so did patients with a preoperative alpha-fetoprotein > 400 μg/L, anatomic hepatectomy, long operation time, and hilar occlusion. Conclusion:Preoperative TACE could be a risk factor for postoperative complications in patients with HCC, especially for the postoperative biliary leakage.
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Objective:To study the clinical efficacy of laparoscopic radical cholecystectomy in the treatment of stage Ⅲ gallbladder cancer.Methods:The clinical characteristics and postoperative follow-up data of 184 patients (male 66, and female 118) who underwent radical cholecystectomy for stage Ⅲ gallbladder cancer at Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, from May 2015 to May 2022, were retrospectively analyzed. The age was (67.0±8.6) years old (range 38 to 85 years old). There were 71 patients in the laparoscopic group and 113 in the open group. The general medical data, surgery-related indicators and complications were analyzed. Follow-up was completed by outpatient visits and by telephone.Results:The laparoscopic group showed better postoperative alanine aminotransferase [67.5 (40.0, 138.5) vs. 104.0 (45.0, 252.2) U/L] and aspartate aminotransferase [41.5 (26.0, 71.2) vs. 53.0 (30.2, 153.5) U/L] recovery, higher albumin levels [32.05 (30.18, 35.20) vs. 30.50 (27.70, 33.50) g/L], earlier abdominal drainage tube removal [8.00(6.00, 10.25) vs. 10.00(6.00, 13.00)d], shorter hospital stay [10.00(8.00, 15.25) vs. 14.00(9.00, 19.00) d] and lower incidences of complications [(14.1%(10/71) vs. 31.9%(36/113)] when compared with the open group (all P<0.05). The 1 year (49.1% vs 61.0%), 2 years (24.0% vs. 28.5%), 3 years (16.0% vs. 14.5%) overall survival ( P=0.640), and the 3 years progression-free survival (18.3% vs. 15.0%, P=0.463) showed no significant difference between the 2 groups. Conclusion:Laparoscopic surgery for AJCC TNM stage Ⅲ gallbladder cancer showed comparable results with open surgery. When compared with open surgery, laparoscopic radical resection of gallbladder cancer had the advantages of earlier removal of abdominal drainage tube, lower incidence of postoperative complications, and shorter hospital stay.
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Objective: Develop an assistant diagnosis system for arrhythinias which can reduce doctors' workload and improve their veracity of diagnosing ECG. Methods: Firstly, this paper achieves filter and detection of waves using wavelet transform and extracts parameters; Secondly, it reduces parameters using rough set and identifies arrhythmias according to relevant rules; At last, it gets the membership of abnormal heart beat by fuzzy neural network. Results: The main modules such as filter, detection of waves and identification of arrhythmias are achieved well, and a complete system is formed. Conclusions: This system can identify nineteen arrhythmaias and get their membership and position. It could assist doctors in making the proper diagnosis on ECG potentially.
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Objective To design LCD system based on MSP430 using LCD controller S1D13700. Methods MSP430's control bus adopted the communication mode of MSC-51 singlechips, and was connected with S1D13700 by 8-bit data bus. The address buses were linked by the modes of indirect address and direct address respectively. Results The design was used for displaying cardiac wave and its parameters in cardiac monitor successfully. Conclusion The S1D13700's driver program, accomplished with standard ANSI-C, is gifted with brilliant versatility, and thus can be used in the design of the portable device.
