Objective To compare the dosimetric parameters of volumetric modulated arc therapy(VMAT),fixed field intensity modulated radiation therapy(IMRT)and three-dimensional conformal radiotherapy(3D-CRT)in the radiotherapy for the patients with locally recurrent nasopharyngeal carcinoma, and to analyze their characteristics. Methods Twelve patients with locally recurrent nasopharyngeal carcinoma were treated with VMAT, IMRT and 3D-CRT plan designed by Pinnacle 9.2 and Preciseplan 2.03 treatment planning system.The dosimetric parameters of targeted volumes and organs at risk were compared between three groups. Results The conformation indexes (CI)of VMAT and IMRT plans were similar,and they were both better than 3D-CRT plan,the difference was significant(P<0.05).The homogeneity index(HI)in three groups were similar,there were no statistically significant differences between them(P>0.05).The monitor units(MU)and beam time in 3D-CRT group were better than those in other two groups,and VMRT group was better than IMRT group,the statistical differences were observed between three groups (P<0.05 ).There were no statistical differences of organs at risk such as brainstem and lens between three groups(P>0.05).The doses of the spinal cord,optic nerve,optic chiasm and temporal lobe of brain in VMAT and IMRT groups were better than those in 3D-CRT group,there were statistical differences between them(P<0.05),and the data in VMAT and IMRT groups were similar,and there were no statistical differences(P>0.05).Conclusion There are differences of the targeted dose distribution between the three kinds of radiation technology, while VMAT and IMRT plans can cover the targeted areas and reduce the received doses of organs at risk.The CI,MU and beam time of VMAT plan are better than those of IMRT plan. 3D-CRT plan only has advantage in the MU and beam time.

Objective:To evaluate the laparoscopic sleeve gastrectomy combined with hiatal hernia repair surgery for weight loss and antireflux.Methods:This study included 21 obese patients with gastroesophageal reflux who underwent laparoscopic sleeve gastrectomy at the Weight Loss Metabolism Center of the Department of Hepatobiliary and Pancreatic Surgery of Zhejiang Provincial People's Hospital from Dec 2019 to Dec 2020. Patients were divided into simple bariatric surgery group (9 cases) and simultaneous combined surgery group (12 cases).Results:In the combined surgery group, 1 case had postoperative gastric leakage. The postoperative body weight, waist circumference, and BMI indexes of the two groups showed a downward trend ( F=5.154, P=0.013; F=14.319, P<0.001; F=6.725, P=0.004). There was a statistically significant difference in the excess weight loss in both the two groups at 6 months after the operation compared to 1 month after the operation ( t=8.927, P<0.001; t=8.926, P<0.001). There was no statistically significant difference in postoperative lower esophageal sphincter resting pressure and Gerd symptom score in the bariatric surgery group compared with preoperative ( t=-0.891, P=0.507; t=0.629, P=0.298). The postoperative Gerd symptom score of the patients in the combined surgery group was significantly lower than that before the operation, and the resting pressure of the lower esophageal sphincter was significantly higher than that before the operation, ( t=-10.539, P<0.001; t=5.066, P=0.038). Conclusion:Combined surgery have the same weight loss effect as in simple bariatric surgery in obese patients with gastroesophageal reflux, in addition to stronger anti-reflux effect.

Objective:To investigate the application value of 3D printed model in hemostasis training for laparoscopic sleeve gastrectomy.Methods:The retrospective and descriptive study was conducted. Data were collected from six surgeons who participated in hemostasis training for laparoscopic sleeve gastrectomy using 3D printed model at Zhejiang Provincial People′s Hospital in July 2023. All participants were male, aged (33.5±9.9)years. A 3D printed model simulating bleeding during laparoscopic sleeve gastrectomy was created using hydrogel. Videos were recorded to document the surgeons′ hemostasis techniques and outcomes during laparoscopic sleeve gastrectomy. Two external expert reviewers blindly assessed the training videos using the objective structured assess-ment of technical skills (OSATS) scoring system to evaluate mesentery mobilization, vessel exposure, vessel clipping and bleeding after vessel clipping. Observation indicators: (1) face validity and content validity of the 3D printed model; (2) validity verification of the 3D printed model. Measurement data with normal distribution were represented as Mean± SD. Comparison between groups was conducted using the t test. Results:(1) Face validity and content validity of the 3D printed model. The surgeons′ scores for overall impression, fidelity, texture, appearance, workspace and tactile similarity of the 3D printed model were 4.5±0.6, 4.0±0.6, 3.7±0.5, 4.2±0.8, 3.8±0.8 and 4.2±0.4, respectively. The surgeons′ scores for similarity to real scenarios, operation convenience, learning curve shortening and operation skills improving, patient risk reduction, trainee′s interest enhancing, confidence increasing and recommendation for promotion were 4.0±0.6, 4.2±0.8, 4.3±0.8, 4.3±0.5, 4.3±0.5, 4.0±0.6 and 4.8±0.4, respectively. (2) Validity verification of the 3D printed model. The OSATS scores and operation time to treat bleeding during laparoscopic sleeve gastrectomy for expert surgeons were 18.7±0.6 and (125±12)seconds, respectively, versus 13.7±1.5 and (212±51)seconds for junior doctors, showing significant differences between the two groups ( t=5.30, -2.89, P<0.05). Conclusion:The 3D printed model effectively simulates bleeding scenarios during laparoscopic sleeve gastrectomy and distinguishes between different technical levels of expertise.