Objective To investigate the effect of field angle on the results of in vivo dose validation of electronic portal imaging device(EPID)in patients.Methods Design the mold test and analyze the influence of different mold thicknesses and different frame angles on the 2D γ pass rate.Twenty-three patients who un-derwent radiotherapy in the Department of Radiotherapy of Jinhua Municipal Central Hospital from January to June 2023 were selected as the research object.In vivo dose verification was carried out during treatment to obtain 2D γ pass rate using same-day sector beam CT(FBCT)of planned CT and executive image guided(IG-RT)as reference images,and the influence of field angle on pass rate was analyzed.Results When the frame angle was unchanged,the area of the shooting field was larger than 17 cm×17 cm,and the 2D γ passing rate decreased with the increase of the thickness.The frame angle had no effect on the 2D γ pass rate when the mold thickness was constant.In clinical treatment data,the passage rate of 2D γ near 0°/180° was higher than that near 90°/270°(P＜0.05),and the passage rate near 90°/270° in the FBCT group was higher than that in the IGRT group(P＜0.05).The median passing rate of 3 mm 2D γ was 97.97％in 3％of the 23 patients.The non-IGRT group was 96.81％,the IGRT group was 97.89％,the FBCT group was 98.94％.There was a statistically significant difference in 2D γ passing rate between the non-IGRT group and the IGRT group(Z=-5.083,P＜0.05),and there was a statistically significant difference in 2D γ passing rate between the IGRT group and the FBCT group(Z=-10.657,P＜0.05).Conclusion Clinically,the difference of pass rate in vi-vo dose verification at different rack angles is mainly due to the difference of images within and between ses-sions.Using same-day FBCT as the reference image for in-vivo dose verification can improve the accuracy of pass rate and eliminate the influence of image difference between sessions.

Objective To evaluate the clinical efficacy of a sphincter-preserving technique combining cutting seton and loose seton drainage for the treatment of ischiorectal abscess.Methods A prospective ran-domized controlled trial was conducted involving 184 patients with ischiorectal abscess,who were randomly di-vided into an experimental group(n=92)and a control group(n=92).The experimental group underwent sphincter-preserving surgery combining cutting seton and loose seton drainage,while the control group re-ceived single-stage incision and seton drainage.Clinical outcomes,anal function,operative time,postoperative pain intensity,wound healing time,and pruritus ani were compared between the two groups.Results The sur-gical time of the experimental group was longer than that of the control group[31.50(25.00,40.00)min vs.20.00(20.00,30.00)min],and the difference was statistically significant(P<0.05).On postoperative days 1,3,and 7,the NRS scores for pain were lower than those in the control group,and the wound healing time was shorter than that in the control group[24.00(20.00,25.75)days vs.29.00(26.00,32.00)days],with statistically significant differences(P<0.05).The recent cure rate of the experimental group was lower than that of the control group(88.04%vs.94.57%),and the difference was not statistically significant(P>0.05).After follow-up,the long-term cure rate of the experimental group was lower than that of the control group(84.78%vs.93.48%),and the Wexner score for anal incontinence was lower than that of the control group[1.00(0.00,1.00)vs.1.00(0.00,2.00)],with statistically significant differences(P<0.05).Conclu-sion The sphincter-preserving technique combining cutting seton and loose seton drainage for ischiorectal ab-scess reduces postoperative pain,shortens wound healing time,and effectively protects anal function with reli-able short-term efficacy.However,further improvements are needed to enhance long-term clinical outcomes.

Objective:To investigate the factors affecting the accuracy of electronic portal imaging device (EPID)-based in vivo dose verification in radiotherapy for patients with lung and esophageal cancers, and to recommend the workflow and specifications for the application of the in vivo dose verification. Methods:This study randomly selected 32 patients who received radiotherapy for esophageal and lung cancers at the Department of Radiation Oncology, Jinhua Municipal Central Hospital from May to August 2022, including 14 lung cancer cases and 18 esophageal cancer cases. Using a uRT-linac 506c linear accelerator, these patients were treated according to the dynamic intensity-modulated radiotherapy (dIMRT) and EPID-based In vivo dose verification ( In vivo EPID) plans developed with the uRT-TPOIS planning system. The In vivo dose verification performed during the treatment included 238 fractions of In vivo EPID and 80 fractions of image-guided radiotherapy (IGRT) for the lung cancer cases, as well as 414 fractions of In vivo EPID and 105 fractions of IGRT for the esophageal cancer cases. The 2D γ passing rate for each irradiation field was obtained according to the set threshold value. Furthermore, fractioned irradiation fields with γ-passing rates below the threshold value were analyzed, and primary factors decreasing the γ-passing rate were further analyzed by combining the online CT images and 3D reconstruction-derived dose. Results:For lung and esophageal cancers, the mean γ-passing rates were 95.1% ± 5.7% and 96.5% ± 4.5%, respectively at 3 mm/5%; 91.5% ± 8.4% and 92.2% ± 4.9%, respectively at 3 mm/3%, and 79.1% ± 14.7% and 83.7% ± 8.2%, respectively at 2 mm/2%, indicating no statistically significant differences between two cancers ( P > 0.05). The average γ passing rate for beam orientations near 0°/180° (Group A) was higher than those near 90°/270° (Group B) 3 mm/5%: Z = -25.4, P < 0.05; 3 mm/3%: Z = -26.8, P < 0.05). The IGRT correction of setup errors significantly improved the γ passing rates (96.3% ± 5.1% and 96.4% ± 4.9%, respectively at 3 mm/5%, Z = -5.50, P < 0.05; 92.3% ± 8.0% and 91.3% ± 7.7%, respectively at 3 mm/3%, Z = -9.54, P < 0.05). The results of In vivo dose verification were affected by changes in the volumes and motion of tumors and normal tissues, radiotherapy positioning, and adequacy of pre-treatment preparation. Conclusions:EPID-based In vivo dose verification during radiotherapy can avoid incorrect irradiation. However, it is necessary to standardize the workflow of the EPID-based In vivo dose verification to avoid the decrease in the γ passing rate caused by artificial factors.

Objective:To investigate the adhesion of polydopamine-modified collagen membrane composites to cartilage tissues and the effect on chondrocyte proliferation, and further explore the possibility of their application in autologous chondrocyte transplantation.Methods:Porous collagen membranes were prepared, and the polydopamine-modified collagen membrane composites were constructed by the adsorption method. The physical and chemical properties and structural characteristics of the membranes, such as thermal stability, thermal properties, porous structure, and surface element composition, were characterized by infrared spectroscopy, thermogravimetric analysis, differential thermal analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy, respectively. The adhesion between the polydopamine-modified collagen membrane and fresh cartilage tissue was tested by a mechanical testing machine. The effects of the membranes on the adhesion and proliferation of rabbit chondrocytes were investigated by in vitro cell culture.Results:The structure and surface element composition of the membranes altered with the increase in the adsorption time of polydopamine, and the capacity of polydopamine increased with the increase in the adsorption time. The thermal stability and thermal properties of collagen membrane materials were not significantly affected by the adsorption of polydopamine. The adhesion of the membrane to cartilage tissue increased with the increase in the amount of absorbed polydopamine. The membranes showed a time-dependent promoting effect on the proliferation of the chondrocytes.Conclusions:The polydopamine-modified collagen membrane has potential application in articular cartilage repair, but more research is required to optimize the membrane before it is used in articular cartilage repair.

Objective:To observe the effect of project-based learning (PBL) in the clinical teaching of radiation physics.Methods:Thirty-two residents specializing in radiotherapy were included in the study. In the experimental group ( n=16), PBL was adopted, while traditional clinical teaching method was employed in the control group ( n=16). After the rotation, the assessment was conducted, as well as a questionnaire survey was performed, including five aspects: overall satisfaction, understanding of radiation physics knowledge, learning motivation, learning burden, and learning efficiency. Results:The assessment score in the experimental group was 86.31±5.41, which was higher than 75.28±5.91 in the control group, and the difference was statistically significant. Residents in the experimental group were satisfied with the effect of PBL.Conclusion:Compared with the traditional teaching method, PBL can improve the learning motivation, efficiency, and performance of radiotherapy residents, which is highly recognized by the residents.

Objective:To analyze and compare the dosimetric differences based on volumetric-modulated arc therapy (VMAT), fixed field intensity-modulated radiotherapy (F_IMRT), and electron irradiation combined with VMAT (E&VMAT) in radiotherapy for breast cancer after modified mastectomy, aiming to provide reference for clinical selection of treatment plan.Methods:Ten patients with the left breast cancer who received radiotherapy after modified mastectomy were randomly selected. The target areas included chest wall and supraclavicular region, and the prescribed dose was 43.5 Gy in 15 fractions (2.9 Gy/F). Based on the Pinnacle 3 planning system, the VMAT, F_IMRT and E&VMAT plans (electron beam for chest wall, VMAT for supraclavicular area) were designed for each patient. The conformity and homogeneity of the target areas, the dose of organs at risk and treatment time were compared. Results:The VMAT plan could improve the dose distribution of the target areas. The conformity index and homogeneity index of the target dose were significantly better than those of the F_IMRT and E&VMAT plans (all P<0.05). The average dose, V 30Gy, V 20Gy, V 10Gy of the left lung in the VMAT plan were significantly better than those in the F_IMRT and E&VMAT plans (all P<0.05). The V 5Gy of the left lung in the VMAT plan was significantly better than that in the F_IMRT plan ( P<0.05). There was no statistical difference in the V 5Gy of the left lung between the VMAT and E&VMAT plans ( P>0.05). The heart, right breast and right lung of the VMAT plan could meet the clinical dose limit requirements. The treatment time of the VMAT, F_IMRT and E&VMAT plans was (326±27) s, (1 082±169) s, and (562±48) s, respectively. Conclusions:Compared with the F_IMRT and E&VMAT plans, the VMAT plan has better quality and shorter treatment time. VMAT plan has higher value in clinical application compared with the F_IMRT and E&VMAT plans.

Matching is a standard method for selecting research objects regarding the observational research, which controls confounding factors and improves statistical efficiency. However, its role in controlling confounding is not consistent in different observational studies. Matching can eliminate the confounding bias of matching variables in cohort studies, but checking on itself cannot eliminate confounding bias in case-control studies. In matched case-control studies, researchers may not accurately judge whether the variable is a confounder. Sometimes the variables that are not confounders are mistakenly matched. In that case, it will result in overmatching, which will lead to the decline of statistical efficiency or the introduction of unavoidable bias or increase of workload. If the real confounding factors are omitted, it will cause confounding bias. Therefore, researchers should consider what kind of matching variable selection criteria should be formulated. A directed acyclic graph is a visual graphic language that can show the complicated causality among different epidemiological research designs. This article analyzes the role of Matching in different observational research designs from the perspective of the directed acyclic graph, formulates the selection criteria for matching variables in matched case-control studies, and provides some reference suggestions for future epidemiological research design.

Epidemiological analysis describes and compares the characteristics of a certain number of people to make causal inferences. The formation of the study population is always the first step. In this paper, we first define the concepts of cross-sections at both individual level and population level and introduce the three assumptions needed in the measurements in observational studies, i. e. the true values of the attributes are stable with time, the attribute variables are independent and the individuals are independent during the measuring process. We also determine that the causal inference research should be unified based on the time of the occurrence or beginning of a postulated cause, or exposure, should be in. Then, based on the dual roles of the population cross-section with causal thinking, we propose that research designs can be classified into two types with different characteristics: history reconstruction research and future exploration research. Finally, we briefly analyze the research design framework and the relationship between estimated effects and different designs. The discussion of the formation of a study population from the perspective of causal thinking can make a foundation for the classification of causal inference research design with appropriate effect parameters, which needs to be further studied.

Objective:To investigate the efficacy of tacrolimus combined with irbesartan in treating female patients with lupus nephritis and its effect on serum levels of high mobility protein B1(HMGB1) and receptor for advanced glycation products(RAGE).Methods:Sixty female patients with lupus nephritis admitted to the First People's Hospital of Wenling from January 2018 to May 2019 were included and divided into control group and observation group according to the random number table method, with 30 cases in each group.The control group received tacrolimus.The observation group was treated with irbesartan on the basis of the control group.After 6 months of continuous treatment, the renal function, scores of lupus nephritis activity index(SLE-DAI) and chronic disease index(SLE-CI), the efficacy, and serum levels of HMGB1 and RAGE were compared between the two groups.Results:Compared with the control group, the serum levels of creatinine(SCr)[(76.46±9.09)μmol/L], urea nitrogen(BUN)[(6.71±0.88)mmol/L], 24h urinary protein quantification[(1.38±0.21)g/24h], scores of SLE-DAI[(9.09±1.41)points] and SLE-CI[(1.17±0.17)points] were significantly reduced in the observation group after treatment, and the plasma albumin(Alb)[(35.08±5.11)g/L] and estimated glomerular filtration rate(eGFR)[(57.79±6.94)mL/min] were significantly increased (all P<0.01). The total effective rates of the observation group and the control group were 90.00% and 63.33%, respectively, and the difference between the two groups was statistically significant(χ 2=4.565, P<0.05). Compared with the control group, the serum levels of HMGB1[(52.31±7.13)μg/L] and RAGE[(1.11±0.18)μg/L] in the observation group were significantly reduced after treatment(all P<0.01). Conclusion:The efficacy of tacrolimus combined with irbesartan in the treatment of female patients with lupus nephritis is significant, and it can inhibit serum levels of HMGB1 and RAGE.

Objective:To explore the enhancement effect of different concentrations of contrast media on blood vessels and hollow organs in CT enterography.Methods:Sixty patients with CT enterography were enrolled from January to August 2019 at Shanghai Ninth People's Hospital, and were prospectively randomly divided into three groups (group A: 90 ml 400 mg/ml contrast media, group B: 90 ml 350 mg/ml contrast media, and group C: 79 ml 400 mg/ml contrast media). Evaluation parameters included CT value, signal noise ratio (SNR) and contrast noise ratio (CNR) of main abdominal vessels (abdominal aorta, superior and inferior mesenteric atery, jejunal artery, ileum artery, superior and inferior mesenteric vein), jejunum, ileum and inflammatory bowel disease. The overall image quality and direct jejunum ileum artery quality scores were evaluated. One-way ANOVA was used to compare the parameters among the three groups.Results:There was no statistical difference in CT value, SNR and CNR of each measurement index among the three groups in plain scan ( P>0.05). The CT value, SNR and CNR of abdominal aorta, superior mesenteric artery, inferior mesenteric artery, jejunal artery and ileal artery in group A and C were higher than those in group B in arterial phase ( P<0.05), but there was no significant difference between group A and group C ( P>0.05). The CT value, SNR and CNR of superior mesenteric vein, inferior mesenteric vein, normal jejunum, ileum and inflammatory lesions in group A were higher than those in group B and C in venous phase ( P<0.05), but there was no significant difference between group B and group C ( P>0.05). The overall image quality scores of group A, B and C were (3.8±0.7), (3.4±0.6), (3.4±0.6), respectively, with no significant difference ( F=3.075, P=0.054). The direct jejunum ileum artery scores of the three groups were (3.5±0.5), (3.1±0.5), (3.4±0.5), respectively, the difference was statistically significant ( F=3.684, P=0.031). Conclusion:At the same injection rate and scanning parameters, contrast media at 400 mg/ml can provide better vessel and hollow organ enhancement.