ObjectiveTo test a three-dimensional dose verification system,which reconstructing dose to anatomy based on modeling and online measurements ( RDBMOM ),and to evaluate the accuracy and feasibility of its application in clinical intensity-modulated radiotherapy (IMRT) quality assurance.Methods Phantom plans of regular and irregular fields were selected for the testing.All test plans were implemented and the dose distributions were measured using the thimble ion-chamber and two-dimensional ion-chamber array,the accuracy of RDBMOM were then evaluated by comparing the corresponding results.Two practical treated nasopharyngeal carcinoma IMRT plans were verified with RDBMOM and the clinic significancy were valued.ResultsCompared with measurements of the thimble ion-chamber,deviations of RDBMOM were within 1％ in all tested cases except small field of 3 cm ×3 cm.The largest deviation of reconstructed dose in IMRT cases was 2.12％.The dose profile reconstructed by RDBMOM coincided with the measurement using two-dimensional ion-chamber array.The γ rates (3％/3 mm) were 94.56％ - 100％.The RDBMOM verification of IMRT cases shown that the γ rate ＞ 99％ in total and ＞ 98％ in planning target volume,deviation in D95 ＜0.4％,but the largest deviations in mean dose of the parotids and lens were 2.97％ and 59.58％ respectively.ConclusionsAccuracy of the tested system satisfies the demand of IMRT dose verification.RDBMOM is able to provide information of volumetric dosimctry and anatomical location of dose error,which is benefit for evaluating the clinical value of verification results.

Objective:To examine the influencing factors of endothelial injury using the structural equation model (SEM).Methods:A total of 6 861 asymptomatic individuals free of cardiovascular disease underwent health examinations at the health management center of the third Xiangya hospital, Central South University from May 2015 to August 2020. And collected their questionnaire and checkup data. Spearman′s rank correlation coefficient was used to analyze metabolic factors and brachial artery flow-mediated dilatation (FMD). Exploratory factor analysis (3 430/6 861) and confirmatory factor analysis (3 431/6 861) were conducted on the diet items. An SEM was constructed using the diet pattern data, cardiovascular risk factors and FMD, and using multi-path regression analysis to determine the correlation between the indicators.Results:Based on the factor analysis, diet items were divided into three patterns: healthy food, meat, and supplementary food. The SEM indicated that age ( β=0.27) and blood pressure ( β=0.12) had obvious effects on low FMD. Triglyceride ( β=0.03), fasting blood glucose ( β=0.04), and body mass index ( β=0.08) were positively correlated with low FMD. On the upstream, healthy food was negatively correlated with blood pressure ( β=-0.04) and body mass index ( β=-0.04), meat was positively correlated with triglyceride ( β=0.33), blood pressure ( β=0.06), fasting blood glucose ( β=0.20), and body mass index ( β=0.16), and supplementary food was negatively correlated with fasting blood glucose ( β=-0.30). This was the only pattern that was directly correlated with FMD ( β=0.05). Conclusions:SEM is an effective method to analyze the influence of various risk factors on the population and the relationship between individual indicators. This study revealed direct and indirect correlations between age, diet pattern, cardiovascular-metabolic risk, and FMD impairment. Comprehensive control of dietary patterns and metabolic indicators could prevent and improve early cardiovascular injury.

Humans ; Cardiac Resynchronization Therapy ; Cardiac Pacing, Artificial ; Heart Ventricles ; Heart Failure/therapy* ; Treatment Outcome ; Electrocardiography ; Ventricular Function, Left

Objective: To assess the interobserver variations in delineating the planning target volume (PTV) and organs at risk (OAR) using different contouring methods during intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC), aiming to provide references for the quality control of multi-center clinical trials. Methods: The PTV and OAR of CT image of 1 NPC patient manually delineated by 10 physicians from 8 different radiation centers were defined as the " manual contour group" , and the OAR auto-contoured using the ABAS software and modified by the physicians were defined as the " auto+ manual contour group" . The maximum/minimum ratio (MMR) of the PTV and OAR volumes, and the coefficient of variation (CV) for different delineated contours were comparatively evaluated. Results: Large variation was observed in the PTV and OAR volumes in the manual contour group. The MMR and CV of the PTV were 1.72-3.41 and 0.16-0.39, with the most significant variation in the PTV_nd (MMR=3.41 and CV=0.39 for the PTV_nd-L). The MMR and CV of the manually contoured OAR were 1.30-7.89 and 0.07-0.67. The MMR of the temporal lobe, spinal cord, temporomandibular joint, optic nerve and pituitary gland exceeded 2.0. Compared with the manual contour group, the average contouring time in the auto+ manual group was shortened by 68% and the interobserver variation of the OAR volume was reduced with an MMR of 1.04-2.44 and CV of 0.01-0.37. Conclusions Large variation may occur in the PTV and OAR contours during IMRT plans for NPC delineated by different clinicians from multiple medical centers. Auto-contouring+ manually modification can reduce the interobserver variation of OAR delineation, whereas the variation in the delineation of small organs remains above 1.5 times. The consistency of the PTV and OAR delineation and the possible impact upon clinical outcomes should be reviewed and evaluated in multi-center clinical trials.