The protection effect of flash-radiotherapy(Flash-RT)with super-high dose on normal tissue has obtained wide attention in therapeutic radiology since it was found in 2014 year.The increasing research demand of Flash-RT with super-high dose-rate proposed new challenge for the existing radiotherapy equipment.Based on the demands of FLASH-RT research and clinical application,this review analyzed the proposed new requirement of Flash-RT for equipment,and introduce current scientific facilities with the experimental ability of X-ray FLASH-RT,as well as the situation of the specialized FLASH-RT equipment which were developing.The research of Flash-RT mechanism need the existing equipment with high-energy X-ray source develop toward high power,while the clinical application of Flash-RT demand these transient high-power devices should possess a series of radiotherapy techniques such as multi angle irradiation,conformal radiotherapy and others.Currently,China's X-ray FLASH-RT research is at the forefront of the world,which is expected to achieve the first breakthrough of high-end medical equipment in the X-ray Flash RT field.

OBJECTIVE To study the cost-utility threshold （WTP/Q） based on the preference of the population in Liaoning province with willingness-to-pay（WTP） survey method， and to provide reference for decision-making. METHODS Using the method of questionnaire survey， quota sampling combined with snowball sampling were used to conduct telephone interviews with the general population in Liaoning province， collect data and analyze it. Probit regression combined with generalized linear model was used to analyze the relevant factors affecting WTP/Q. RESULTS A total of 755 general people were recruited. The WTP/Q of Liaoning population was 119 175 yuan，the average WTP/Q for improving the quality of life was 84 902 yuan， and the average WTP/Q for extending the survival period was 188 005 yuan. The analysis of influential factors showed that the older the age， the lower the probability of people purchasing medical interventions； the higher the education level and income， the greater the WTP/ Q； at the same time， the physical feelings of the interviewee， such as pain and depression， could also affect the WTP/Q results； compared with the scenario of improving quality of life， the WTP/Q for the extended survival period was higher. CONCLUSIONS The WTP/Q of Liaoning province based on the WTP survey method is about 2.07 times of the per capita gross domestic product of Liaoning province in the same period. The WTP/Q for extending survival period is about 2.21 times that of improving the quality of life. Therefore， interventions to improve quality of life and to extend the survival period need to be treated differently， in measurement or decision-making.

Objective:To investigate the relationship between triglyceride glucose index (TyG) and body inflammation.Methods:The data were obtained from a baseline survey in population in Xi'an in natural population cohort study in northwest China established in 2018-2019. Based on TG and FPG, TyG/TyG-BMI was constructed to reflect insulin resistance (IR) in the body, and systemic immune-inflammation index (SII) reflecting inflammation in the body was constructed using neutrophil, lymphocyte, and platelet counts. A logistic regression model was used to explore the relationship between the TyG and the SII.Results:A total of 11 491 subjects were included in the analysis. After adjusting for covariates, each unit increase in the TyG increased the risk of high SII by 21% ( OR=1.21, 95% CI:1.12-1.30). The risk of high SII in the group with the TyG in Q4 was 1.34 times higher than that in the group Q1 ( OR=1.34, 95% CI:1.18-1.52). Both sensitivity analysis and subgroup analysis further confirmed the stability of the association between the TyG and the SII. In the population with a BMI ranging from 18.5 to 23.9 kg/m 2, for every unit increase in the TyG as a continuous variable, the risk for high SII increased by 31% ( OR=1.31, 95% CI:1.18-1.45). As a categorical variable, the risk for high SII in the Q4 group was 1.52 times higher than that in the Q1 group ( OR=1.52, 95% CI:1.27-1.83). In a population with BMIs ranging from 24.0 to 27.9 kg/m 2, for every unit increase in the TyG as a continuous variable, the risk for high SII increased by 20% ( OR=1.20, 95% CI:1.07-1.35), and there was no significant difference when it was a categorical variable. Conclusions:The increase in IR is closely related to the development of inflammation in the body, and BMI may regulate their relationship. Early prevention of elevated IR levels before overweight or obesity may have a positive effect on the control of inflammation in the body.

Objective:To develop a mesenteric creeping fat index (MCFI) based on CT enterography (CTE) to characterize the degree of creeping fat wrapping around the inflamed gut in Crohn disease (CD), and to assess the relationship between MCFI and the inflammatory intestinal stricture.Methods:From December 2018 to July 2019, the patients with CD who underwent surgery in the First Affiliated Hospital of Sun Yat-Sen University were prospectively collected. The extent of perienteric mesenteric vessels wrapping around the gut was reconstructed to develop MCFI based on CTE images. The intestinal stricture index was obtained by calculating the ratio of the maximal upstream luminal diameter divided by the minimum luminal diameter apparent within the stricturing region. Using region-by-region correlation between CTE and surgical specimen, creeping fat score in intestinal specimen was obtained by assessing the extent of creeping fat wrapping around the resected bowel segment, and HE staining was performed on the bowel specimen corresponding to creeping fat to obtain the pathological inflammatory score. The Spearman correlation analysis was used to evaluate the correlation between MCFI, creeping fat score in intestinal specimen, and inflammatory score, intestinal stricture index. The ROC curve analysis was used to assess the accuracy of MCFI in distinguishing moderate-severe and mild inflammatory bowel walls.Results:Totally 30 CD patients were enrolled. The creeping fat score in intestinal specimen positively correlated with pathological inflammatory score ( r s=0.403, P=0.027) and with intestinal stricture index ( r s=0.642, P<0.001). MCFI positively correlated with creeping fat score in intestinal specimen ( r s=0.840, P<0.001), with pathological inflammatory score ( r s=0.497, P=0.005), and with intestinal stricture index ( r s=0.599, P<0.001). ROC analysis showed that the area under the curve of MCFI for differentiating moderate-severely from mildly inflammatory bowel walls was 0.718 (95%CI 0.522-0.913). Using MCFI≥4 as a cutoff value, the sensitivity and specificity were 81.8% and 47.4%, respectively. Conclusions:There was a correlation between creeping fat and inflammatory intestinal strictures in CD. MCFI can non-invasively depict the degree of creeping fat wrapping around the gut and assess the inflammatory intestinal stricture.

Objective To determine the correlation between intravoxel incoherent motion (IVIM) parameters and both histologic inflammatory and fibrotic grades of Crohn disease (CD) in adults. Methods Prospectively, 17 patients (77 lesions) with a clinical and pathological diagnosis of CD in the first affiliated hospital of sun yat-sen university from July 2015 to June 2016 underwent MRE 15 days before surgery. All patients underwent T2WI, IVIM and enhanced MRI and calculated IVIM parameters include diffusion-related coefficient (D), perfusion-related coefficient (D*) and perfusion-related fraction (f). Histological intestinal inflammation and fibrosis was scored using the surgical histopathology as reference standard and further divided into mild-moderate (score 1 to 2) and severe (score 3 to 4) groups. Intestinal microvessel density (MVD) were also analyzed. Differences in IVIM parameters among different histological inflammation and fibrosis grades were assessed with the Kruskal-Wallis test. The Wilcoxon test was used for assessing differences in f between mild-moderate and severe fibrosis. The bivariate correlations between IVIM parameters and histological inflammation and fibrosis grades were analyzed using partial correlation . The bivariate correlations between IVIM parameters and MVD were analyzed using Spearman rank correlation. The areas under the receiver operating characteristics curves (AUROC) were analyzed to evaluate the efficacy for distinguishing severe from mild-moderate fibrosis. Results Of 77 surgical specimens, there were 41 mild-moderate and 36 severe inflammatory bowel segments, along with 22 mild-moderate and 55 severe fibrotic bowel segments. Positive correlation was shown between histologic inflammatory and fibrotic scores (r=0.592, P<0.01). MVD (42.7 ± 39.9)/HP presented weak positive correlation with histologic inflammatory scores (r=0.332, P=0.003) while no correlation with histologic fibrotic scores (r=0.129, P=0.262) was presented. Neither the D nor the D* values significantly correlated with histologic inflammation or fibrosis (P>0.05) while the f value significantly correlated with both histologic inflammation and fibrosis (P<0.05). Significant correlation was present between the f value and histologic inflammatory and fibrotic scores, respectively (r=-0.280, -0.520;P<0.05). There was significant difference in the f value between mild-moderate and severe fibrosis(Z=-5.255,P<0.01). The AUROC for the f value to distinguish between patients with mild-moderate fibrosis and severe fibrosis were 0.885. Using a threshold fractional perfusion of 0.33, the sensitivity and specificity values were 95.5％ and 81.8％, respectively. No correlation between f, D and D*value with histologic fibrotic scores (r=0.129, P=0.262) was presented. Conclusion The f value derived from IVIM could help to evaluate the severity of intestinal inflammation and fibrosis CD in adults.

Objective To explore the diagnostic values of combined detection of serum procalcitonin (PCT) and β2 microglobulin (β2MG) in tsutsugamushi disease.Methods Serum PCT and β2MG were compared in cases of tsutsugamushi disease and fever patients at the same time,who were hospitalized at Fourth Affiliated Hospital of Guangxi Medical University from June 2014 to May 2017.The best diagnosis cut-off value of tsutsugamushi disease was calculated by receiver operating characteristic (ROC) curve.Results A total of 57 cases of tsutsugamushi disease,40 cases of sepsis,17 cases of acquired immunodeficiency syndrome (AIDS),17 cases of severe community-acquired pneumonia (SCAP),63 cases of common community-acquired pneumonia (CCAP),14 cases of pulmonary tuberculosis (PTB),20 cases of upper respiratory tract infection,13 cases of other infectious fever and 28 cases of non-infectious fever patients were selected.The level of serum PCT in tsutsugamushi disease [0.87 (0.68-1.34) μg/L] was higher than those in AIDS [0.47 (0.20-1.12) μg/L],CCAP [0.17 (0.09-0.51) μg/L],PTB [0.13 (0.05-0.18) μg/L],upper respiratory tract infection [0.23 (0.05-0.48) μg/L] and non-infectious fever [0.09 (0.06-0.13) μg/L],but was lower than those in sepsis [5.00 (1.04-18.78) μg/L] and SCAP [3.35 (0.76-14.41) p,g/L,P ＜ 0.05],while the difference was not significant compared with other infectious fever [0.76 (0.13-1.99) μg/L,P ＞ 0.05].The level of serum β2MG in tsutsugamushi disease [(5.67 (4.47-7.90) mg/L] was higher than those in sepsis [2.83 (2.10-4.54) mg/L],AIDS [3.85 (3.19-5.22) mg/L],SCAP [3.83 (2.98-5.58) mg/L],CCAP [1.99 (1.51-2.75) mg/L],PTB [1.92 (1.37-3.00) mg/L],upper respiratory tract infection [2.02 (1.25-2.74) mg/L],other infectious fever [2.45 (1.51-4.12) mg/L] and non-infectious fever [2.99 (2.06-4.30) mg/L,P ＜ 0.05].ROC curve showed that the most suitable diagnosis cut-off value of serum PCT in tsutsugamushi disease was 0.53 μg/L,the sensitivity was 94.7％,and the specificity was 60.4％.The critical value of serum β2MG was 3.74 mg/L in diagnosis of tsutsugamushi disease,its corresponding sensitivity and specificity were 91.2％ and 75.9％,respectively.The sensitivity and specificity of combined serum PCT and β2MG in diagnosis of tsutsugamushi disease was 87.7％ and 86.3％,respectively.Conclusion Combined detection with serum PCT and β2MG can improve early diagnosis of tsutsugamushi disease.

Objective To assess the diagnostic value of magnetization transfer MRI (MTI) for bowel inflammation and fibrosis in humans with Crohn disease (CD). Methods From July 2014 through April 2017, 31 patients with a confirmed diagnosis of CD were prospectively recruited from the First Affiliated Hospital of Sun Yat Sen University. They were scheduled for elective surgery due to bowel obstruction and other complications, and underwent preoperative MR enterography (MRE) and MTI within 15 days of surgery. All cases had available intestinal specimens identified on MRE and resected bowel segments for region by region matching. All patients underwent breath hold conventional MRE and MTI examinations, and then the magnetization transfer ratios (MTRs) of pathological bowel segments were measured. Using region by region correlation between MTI and surgical specimen, the bowel segments were resected to stain with HE for evaluating bowel inflammation, Masson for bowel fibrosis, and typeⅠcollagen staining for the deposition of typeⅠcollagen within the bowel walls. The histologic sections from the most severe areas were scored as 0 (normal), 1 (mild), 2 (moderate) and 3 (severe). The correlations between MTR and histologic scores were analyzed by using Spearman rank correlation or partial correlation. The differences in MTR among different grades of bowel fibrosis were analyzed by one way ANOVA. The efficacy of MTR for predicting bowel fibrosis was evaluated by receiver operating characteristic curves analysis. The difference in MTRs between purely inflammatory bowel walls and mixed fibrotic and inflammatory bowel walls was analyzed by Student s t test. Results Sixty two resected bowel specimens from 31 patients including 9 purely inflammatory bowel walls and 53 mixed fibrotic and inflammatory bowel walls were obtained in this study. There were significant differences in MTR among non fibrotic [(21.45 ± 2.65)%], mildly [(30.88 ± 6.14)%], moderately [(35.14 ± 4.31)%] and severely [(35.14 ± 4.31)%] fibrotic walls (F=38.397,P<0.01). MTRs strongly correlated with fibrosis scores (r=0.681, P<0.01). High accuracy of MTRs was shown (curve under area=0.905, P<0.01) for differentiating moderately severely fibrotic from non fibrotic and mildly fibrotic bowel walls. Using MTR of 31.50% as a cutoff value, the sensitivity and specificity were 93.6% and 80.0%, respectively. The MTRs of purely inflammatory bowel walls [(21.45 ± 2.65)%] were significantly higher than that of mixed fibrotic and inflammatory [(36.28±5.21)%] bowel walls (t=-13.052,P<0.01). MTRs correlated with the scores of type Ⅰ collagen (r=0.325, P=0.044) but did not correlate with inflammation scores (r=-0.024, P=0.857). Conclusions MTI enables quantitative evaluation of bowel fibrosis in patients with CD and can be used to differentiate purely inflammatory CD from mixed fibrotic and inflammatory CD.

[Objective]To explore the efficacy of T2* mapping for evaluating inflammatory activity in the patients with Crohn disease(CD).[Methods]A total of 98 CD patients underwent MR enterographywith T2*WI. T2* values were measured by put-ting regions of interest on the thickening bowel wall on T2*mapping. The activity of bowel segment was scored by magnetic resonance index of activity(MaRIA),to analyze the relationship between T2*values with CD activity.[Results]A total of 160 bowel segments were evaluated and includedinactive(MaRIA<7,n=26),mild(7≤MaRIA<11,n=23),and moderately-severe(MaRIA≥11, n = 111)active lesions. The differences in T2* values amongthese three groups were significant(all P < 0.05). T2* values of 160 bowel segments correlatedclosely withMaRIA(r=0.743,P<0.05). High accuracy of T2*values was shown for differentiating inac-tive from active CD(AUC=0.877)anddifferentiating inactive-mild from moderate-severe CD(AUC=0.848). The threshold T2*value of 20 ms allowed differentiation of mild from moderate-severe CD with74.5%sensitivity and 84%specificity.[Conclusions]T2*values, as thequantitative indexof T2*mapping,correlate well with CD activity and showsatisfiedefficacy for diagnosing inflammatoryactivity.

Objective To explore the diagnostic value of magnetization transfer imaging (MTI) and DWI for detecting intestinal wall property of crohn's disease (CD). Methods Forty four patients with CD were prospectively enrolled in the study, and MR enterography (MRE), MTI and DWI were performed. According to MRE findings, patients were divided into three subgroups:acute inflammatory group, chronic fibrotic group and combined inflammatory with fibrotic group. Intestinal wall T2WI signal, magnetization transmisson rate (MTR) and ADC value were measured on MRE, MRI and DWI imagings, respectively. The differences of MTR and ADC among the three groups were analyzed by one-way ANOVA;the differences of T2WI scores were analysed by Kruskal Wallis;the differences of MTR and ADC values between normal and pathological intestinal wall were analyzed by paired t test;ROC curve were used to evaluate the CD fibrosis and inflammation diagnostic efficiency of MTI ana DWI based on MRE signs. Results Among the 44 cases, 11 cases were in the acute inflammatory group, 18 cases were in the chronic fibrotic group and other 15 cases were in the combination group. The T2WI score, MTR and ADC among the three groups showed significant differences (all P<0.01).The mean MTR and ADC of pathological intestinal wall of the 44 cases were (40.77±6.05)%and (1.04±0.18)× 10-3mm2/s, and the adjacent normal bowel were (21.75±4.17)%and (1.97 ± 0.23) × 10- 3mm2/s, respectively. Moreover, the difference of the above values showed significant differences (t=19.12,-21.80 respectively, all P<0.01). There was a negative correlation between MTR and T2WI score (r=-0.71,P<0.01). While ADC value was positively correlated with T2WI score (r=0.80, P<0.01). Using ROC curve analysis to differentiate the CD fibrosis from acute inflammation, the area under the curve (AUC) of MTR and ADC were 0.97 and 0.96 ,respectively. Conclusions Both MTI and DWI can be used to assess the properties of intestinal wall, which has the same diagnostic efficacy to identify the acute inflammation and fibrosis.

[Objective] To analyze the image findings of MR enterography (MRE) and diffusion weighted imaging (DWI) in Crohn disease (CD) and to discuss the diagnostic value of MRI for evaluating the activity of CD.[Methods] 26 patients proved by clinical,imaging and pathological data were enrolled in this study.The intra-/extra-intestinal image features of CD were retrospectively analyzed,and the intestinal lesions were evaluated by MRE+DWI scoring system.The differences in image features of active and inactive CD were compared.[Results] 26 bowel segments were evaluated and included active (n =20) and inactive CD (n =6).The intestinal performance of CD included wall thickening,T2WI hyperintensity and hyperenhancement.The pathological changes of active CD were more serious when comparing with that of inactive CD.DWI showed hyperintensity in the affected bowel wall.ADC of active C D [(0.9 ± 0.2) × 10-3 mm2/s] was significantly lower than that of inactive CD [(1.5 ± 0.4)× 10-3 mm2/s] (P ＜ 0.001).Extra-enteric performance of active CD included comb sign,lymphadenectasis of mesentery,mesenteric exudation,fistula and abdominal abscess.[Conclusion] MRE combined with DWI can accurately assess CD activity and diagnose extra-enteric complications.