One of the main technical challenges when integrating magnetic resonance imaging (MRI) systems with medical linear accelerator is the strong interference of fringe magnetic fields from the MRI system with the electron beams of linear accelerator, making the linear accelerator not to work properly. In order to minimize the interference of magnetic fields, a magnetic shielding cylinder with an open structure made of high permeability materials is designed. ANSYS Maxwell was used to simulate Helmholtz coil which generate uniform magnetic field instead of the fringe magnetic fields which affect accelerator gun. The parameters of shielding tube, such as permeability, radius, length, side thickness, bottom thickness and fringe magnetic fields strength are simulated, and the data is processed by MATLAB to compare the shielding performance. This article gives out a list of magnetic shielding effectiveness with different side thickness and bottom thickness under the optimal radius and length, which showes that this design can meet the shielding requirement for the MRI-linear accelerator system.
ObjectiveTo explore the effect of donation after citizen death (DCD) kidney transplantations performed in Sichuan.MethodsThe data of 97 cases of DCD kidney transplantations performed in West China Hospital of Sichuan University between January 2012 and March 2016 was retrospectively reviewed. The 53 donors were aged from 7 months to 54 years (with a median of 28 years, and lower quartile of 15 years and upper quartile of 45 years), including 40 males and 13 females; the causes of death included craniocerebral trauma in 21 cases, craniocerebral tumor in 12 cases, cerebrovascular accident in 15 cases, hypoxic-ischemic encephalopathy in 4 cases, and hydrocephalus in 1 case. The 97 recipients were aged from 18 to 66 years (with a median of 39 years, and lower quartile of 30 years and upper quartile of 44 years), including 71 males and 26 females. The recipients were classified into C-Ⅰ (n=36) and C-Ⅲ (n=61) according to type of donation. The baseline and perioperative situation of the donors and recipients, and the postoperative kidney function, infection, recipient survival and kidney survival of the recipients were analyzed.ResultsAfter transplantation, none of primary graft nonfunction occurred but delayed graft function (DGF) occurred in 26 cases. There were no significant differences in creatinine level between C-Ⅰ and C-Ⅲ recipients at 1 week [(226.71±187.46) vs. (249.94±249.84) μmol/L, P=0.636], 1 month [(136.32±63.34) vs. (157.37±147.83) μmol/L, P=0.428], 3 months [(110.51±25.26) vs. (115.02±36.60) μmol/L, P=0.527] and 12 months [(103.42±21.57) vs. (104.18±39.36) μmol/L, P=0.911] after transplantation, as well as acute rejection [13.9% vs. 19.7%, P=0.469] and complications at early time after transplantation. There were no significant differences in 1-year recipient survival rate (91.7% vs. 93.4%) and 1-year kidney survival rate (100.0% vs. 91.8%) between C-Ⅰ and C-Ⅲ recipients.ConclusionDCD kidney transplantation has excellent short-term outcomes despite a high incidence of early DGF, and may represent another potential method to safely expand the donor pool.
Objective To explore the effect of kidney transplantation on chronic prostatitis-like symptoms. Methods A total of 300 male renal transplant recipients between January 2015 and January 2017 were collected in the study. All recipients received the questionnaire survey of the National Institute of Health-Chronic Prostatitis Symptom Index (NIH-CPSI) preoperatively and at 3 months after transplantation. The score and relevant risk factors were statistically analyzed. Results A total of 210 recipients (70.0%) completed questionnaire effectively, in whom 150 (71.4%) had preoperative and 90 (42.9%) had postoperative chronic prostatitis-like symptoms, respectively. In the 210 patients, the preoperative and postoperative pain score was 6.57±3.12 vs. 3.57±3.16 (P<0.001), voiding score was 3.71±2.38vs. 3.29±2.66 (P=0.116), quality of life score was 7.57±1.60 vs. 5.14±2.75 (P<0.001), and the total NIH-CPSI score was 17.86±3.81vs. 12.00±6.65 (P<0.001), respectively. The severity of chronic prostatitis-like symptoms was alleviated significantly after kidney transplantation. Conclusion Kidney transplantation can alleviate the chronic prostatitis-like symptoms significantly, and improve the quality of life in uremia patients.
ObjectiveTo explore the reliability and safety of continuous monitoring of vital signs in patients using wireless wearable monitoring devices after video-assisted thoracoscopic surgery (VATS) for lung cancer. MethodsThe patients undergoing VATS for lung cancer in West China Hospital, Sichuan University from May to August 2023 were prospectively enrolled. Both wireless wearable and traditional wired devices were used to monitor the vital signs of patients after surgery. Spearman correlation analysis, paired sample t test and ratio Bland-Altman method were used to test the correlation, difference and consistency of monitoring data measured by the two devices. The effective monitoring rate of the wireless wearable device within 12 hours was calculated to test the reliability of its continuous monitoring. ResultsA total of 20 patients were enrolled, including 15 females and 5 males with an average age of 46.20±11.52 years. Data collected by the two monitoring devices were significantly correlated (P<0.001). Respiratory rate and blood oxygen saturation data collected by the two devices showed no statistical difference (P>0.05), while heart rate measured by wireless wearable device was slightly lower (\begin{document}$ \bar{d} $\end{document}=−0.307±1.073, P<0.001), and the blood pressure (\begin{document}$ \bar{d} $\end{document}=1.259±5.354, P<0.001) and body temperature(\begin{document}$ \bar{d} $\end{document}=0.115±0.231, P<0.001) were slightly higher. The mean ratios of heart rate, respiratory rate, blood oxygen saturation, blood pressure and body temperature collected by the two devices were 0.996, 1.004, 1.000, 1.014, and 1.003, respectively. The 95% limits of agreement (LoA) and 95% confidence interval of 95%LoA of each indicator were within the clinically acceptable limit. The effective monitoring rate of each vital signs within 12 hours was above 98%. ConclusionThe wireless wearable device has a high accuracy and reliability for continuous monitoring vital signs of patients after VATS for lung cancer, which provides a security guarantee for subsequent large-scale clinical application and further research.