ObjectiveThis paper aims to explore the risk factors for chronic atrophic gastritis （CAG） with turbidity toxin accumulation syndrome and establish a prediction model. MethodsClinical data of 180 patients with CAG who participated in the "clinical study of Xianglian Huazhuo Particles blocking CAG cancer transformation" of Hebei Sheng Zhong Yi Yuan from July 2021 to March 2022 were collected. After confounding factors were controlled by propensity score matching， patients were divided into a training set （namely dev） and a validation set （namely vad） in a seven to three ratio. The risk factors for CAG with turbidity toxin accumulation syndrome in the training set were investigated by using univariate Logistic regression analysis and least absolute shrinkage and selection operator （namely Lasso） regression algorithms. Subsequently， a model， named model 1se， was developed by using the training set data to predict the risk factors for CAG with turbidity toxin accumulation syndrome. The accuracy of the prediction model was assessed by using various methods， including the receiver operating characteristic （ROC） curve， Hosmer-Lemeshow test （H-L）， calibration plot， and decision curve analysis （DCA）. ResultsAge， body mass index （BMI）， family history of cancer， job and life satisfaction， yellow and greasy fur with slippery pulse， and heavy body sensation were independent risk factors of the model. The prediction model showed excellent predictive value for both the training and validation sets. ConclusionThe established prediction model for CAG with turbidity toxin accumulation syndrome has high discrimination and excellent calibration， which could provide an excellent clinical basis for disease diagnosis and individualized treatment of patients.

ObjectiveThis paper aims to explore the risk factors for chronic atrophic gastritis （CAG） with turbidity toxin accumulation syndrome and establish a prediction model. MethodsClinical data of 180 patients with CAG who participated in the "clinical study of Xianglian Huazhuo Particles blocking CAG cancer transformation" of Hebei Sheng Zhong Yi Yuan from July 2021 to March 2022 were collected. After confounding factors were controlled by propensity score matching， patients were divided into a training set （namely dev） and a validation set （namely vad） in a seven to three ratio. The risk factors for CAG with turbidity toxin accumulation syndrome in the training set were investigated by using univariate Logistic regression analysis and least absolute shrinkage and selection operator （namely Lasso） regression algorithms. Subsequently， a model， named model 1se， was developed by using the training set data to predict the risk factors for CAG with turbidity toxin accumulation syndrome. The accuracy of the prediction model was assessed by using various methods， including the receiver operating characteristic （ROC） curve， Hosmer-Lemeshow test （H-L）， calibration plot， and decision curve analysis （DCA）. ResultsAge， body mass index （BMI）， family history of cancer， job and life satisfaction， yellow and greasy fur with slippery pulse， and heavy body sensation were independent risk factors of the model. The prediction model showed excellent predictive value for both the training and validation sets. ConclusionThe established prediction model for CAG with turbidity toxin accumulation syndrome has high discrimination and excellent calibration， which could provide an excellent clinical basis for disease diagnosis and individualized treatment of patients.

Objective To construct programmed cell death protein-ligand 1(PD-LI)^hi tolerogenic dendritic cell (tol-DC) derived from bone marrow of DA rats and identify its immunological function. Methods DA rat bone marrow cells were extracted, combined with recombinant mouse granulocyte macrophage colony-stimulating factor and recombinant mouse interleukin (IL)-4, and cultured for 6 days in vitro to induce the differentiation of bone marrow cells into immature dendritic cells (imDC). Lipopolysaccharide was used to stimulate cell maturation and cultured for 2 days to collect mature dendritic cells (mDC). PD-L1 lentiviral vector virus stock solution or equivalent dose lentiviral stock solution was added, and PD-L1^hitol-DC and Lv-imDC were collected after culture for 2 days. The morphology of PD-L1^hitol-DC was observed by inverted phase contrast microscope and transmission electron microscope. Real-time fluorescence quantitative reverse transcription polymerase chain reaction, Western blotting and flow cytometry were used to detect the expression level of specific markers on cell surface. CD8⁺T cells derived from Lewis rat spleen were co-cultured with imDC, mDC, Lv-imDC and PD-L1^hitol-DC, respectively. The levels of inflammatory factors in the supernatant of each group were detected by enzyme-linked immunosorbent assay. The apoptosis of T cells and the differentiation of regulatory T cells (Treg) in each group were analyzed by flow cytometry. Results The morphology of PD-L1^hitol-DC modified by PD-L1 gene was consistent with tol-DC characteristics, and the expression levels of CD80, CD86 and major histocompatibility complex (MHC) on the surface were low. After mixed culture with CD8⁺ T cells, the levels of IL-10 and transforming growth factor (TGF) -β1 in the supernatant of PD-L1^hitol-DC group were higher, the levels of tumor necrosis factor (TNF) -α and IL-17A were lower, and the apoptosis of T cells and Treg differentiation were increased. Conclusions Overexpression of PD-L1 through lentiviral vectors may successfully induce the construction of bone-marrow derived PD-L1^hitol-DC in DA rats, promote the secretion of anti-inflammatory factors and T cell apoptosis, induce the differentiation of Treg, and inhibit the immune response of allogeneic CD8⁺T cells, which provides experimental basis for the next organ transplantation immune tolerance study.

In the field of healthcare service,it is crucial to optimize medical innovation services by combining the preferences of health service providers and demanders(i.e.,stakeholders).The best-worst scaling(BWS)method is a recently developed stated preference method for assessing preferences with distinctive advantages.Nevertheless,there is a lack of a comprehensive introduction to stakeholder preference assessment using BWS,thus constraining its applications and promotion.This paper introduces the process of using BWS to assess service providers'preferences for the Shared Medical Appointment for diabetes(SMART),an integrated healthcare service of medicine and health management,in the hope of providing reference for researchers for promoting the use of BWS in implementation research.

Objective:Based on HyperArc stereotactic radiotherapy(SRT)technique,six-dimensional free bed combined with double mask fixation was used to treat intracranial tumors,and the positioning errors of within batch and between batches were analyzed,so as to provide basis for the accuracy of clinical treatment of this technique.Methods:A total of 13 patients with intracranial tumors who admitted to Peking Union Medical College Hospital from March to July 2023 were retrospectively selected,and they were treated by using HyperArc SRT technique.The validation images of cone-beam computed tomography(CBCT)of within batch and between batches during treatment were analyzed.The positioning errors of three translational direction[left and right(x),head and foot(y)and abdominal and dorsal(z)]and rotational direction were analyzed.The each positioning error was set as group A,and the remaining error after the positioning error was corrected through six-dimensional free bed was set as group B,and the error post treatment was set as group C.The difference between group B and group C was defined as the change of within batch.According to the margin formula,the positioning error of within batch was used to calculate the required range of margin.Results:Under the mode of six-dimensional free bed correction combined with double mask fixation,a total of 59 times of HyperArc SRT on head were performed.In the comparison of the average errors on the six-dimensional direction among groups A,B and C,the errors of group A on x direction and y direction were respectively(0.119±0.039)and(-0.133±0.047)cm,and the differences of them between group A and group B[(0.004±0.002)and(0.018±0.005)cm]were significant(t=2.890,-3.224,P<0.05).There were no significant differences on other directions between the two groups(P>0.05).The error of RX direction of group B was(0.033±0.021)°,and the difference of that between group B and group C[(0.122±0.045)°]was significant(t=-2.306,P<0.05),while there were no significant differences on other directions(P>0.05).In the margin of the design of the plan of intracranial tumors,the x,y and z directions were respectively 0.6,0.9 and 0.4 mm.Conclusion:In the radiotherapy of using HyperArc SRT technique for intracranial tumors,the use of six-dimensional free bed combined with double mask treatment can significantly shorten the margin,and ensure accurate irradiation for gross tumor volume(GTV)and simultaneously reduce the irradiation volume and dose of surrounding normal tissue.

Objective:To establish daily quality assurance workflow based on self-developed phantom to ensure MR-linac performance such as beam accuracy, MR image guidance accuracy, and the clinical treatment workflow to enhance the efficiency of daily quality assurance (QA).Methods:The self-developed phantom was made by 3D printer and used in conjunction with Daily QA-MR detector array. After CT-sim scanning, a treatment plan was designed and transmitted to the accelerator, tests were performed such as image guidance accuracy, beam output and beam quality, the differences in daily QA results between the self-developed phantom and standard phantom recommended by the manufacturer were analyzed by using paired t-test. Results:A total of 24 sets results were collected, the image guide accuracy in the X, Y and Z directions between standard and self-made phantom were (0.1±0.4), (-0.14±0.16), (0.07±0.05) mm and (0±0.02), (-0.02±0.02), (0.02±0.01) mm, respectively, and the differences were statistically significant ( P<0.001, =0.001 and <0.001). Daily QA-MR detector array beam measurement results including output, symmetry, beam quality and field size were -0.11%±0.20%, -0.10%±0.19%, -0.01%±0.08%, (0.4±0.1) mm and (0.2±0.1) mm, respectively. The new process saved 25% (approximately 9 min) of the time compared to the standard process. Conclusions:The new daily QA process for MR-linac is performed based on self-developed phantom and Daily QA-MR detector array. The accuracy and sensitivity meet the requirements and can improve the QA efficiency.

The presence of magnetic fields in a magnetic resonance accelerator (MR-linac) can affect the reference dosimetry, and thus the existing Code of Practices (CoPs) are inadequate for MR-linac. In this article, the characteristics of adsorbed dose to water and ionization chamber response in the presence of magnetic fields were introduced and a formalism for reference dosimetry in MR-linac was developed based on the existing CoPs, aiming to provide reference for dosimetric quality control and research work of MR-linac in China.

Objective:To compare the effects of different appointment regimens on the daily waiting time, fixedness of treatment time and lateness rate of radiotherapy patients.Methods:Medical records of 5488 radiotherapy from 332 patients on the same linear accelerator in West China Hospital of Sichuan University from March to June 2022 were selected. Based on the radiotherapy information integration platform of MOSAIQ, all patients were randomly assigned to the morning class, afternoon class and evening class. Traditional manual appointment regimen was adopted for the morning class, 30 min appointment regimen for the afternoon class, and 15 min appointment regimen for the evening class, respectively. The differences in patient waiting time for treatment, fixedness of treatment time, and lateness rate under different appointment regimens were compared. The fixedness of treatment time and waiting time was determined by one-way ANOVA, and the 2×3 Chi-square test was adopted for the lateness rate. Results:The waiting time in the 15 min appointment, the 30 min appointment and manual appointment groups were (27.08 ± 17.21), (34.57± 19.12) and (41.50 ±20.94) min, respectively. There was statistical significance among three appointment regimens ( F=254.97, P<0.001). The waiting time was the shortest in the 15 min appointment group, followed by the 30 min appointment group, and the manual appointment group (all P<0.001 for two-group comparison). The fixedness of treatment time in the 15 min appointment, the 30 min appointment and the manual appointment groups were (15.60±7.87), (18.69±8.94) and (24.30±15.10) min, respectively. There was statistical significance among three groups ( F=25.23, P<0.001). Among them, the fixedness of treatment time in the 15 min appointment group was the highest, followed by the 30 min appointment group, and the manual appointment group (all P<0.001). The lateness rates in the 15 min appointment, the 30 min appointment and the manual appointment groups were 5.7%, 6.2% and 9.6%, respectively. The lateness rate in the manual appointment group was higher than those in the 15 min appointment and the 30 min appointment groups ( χ2=19.24、14.90, both P<0.001), but there was no statistical significance in the lateness rate between the 15 min appointment and 30min appointment groups ( χ2=0.39, P=0.535). Conclusion:In the clinical practice of conventional intensity-modulated radiotherapy technology carried out by conventional linear accelerator, the 15 min appointment regimen can shorten the waiting time for radiotherapy and improve the fixedness of daily radiotherapy time, which is worthy of clinical promotion.

Objective:To explore the clinical efficacy of the sixth generation CyberKnife (M6) in treating patients with brain metastases, and analyze clinical characteristics and dosimetric factors.Methods:Clinical data of patients with brain metastases who received CyberKnife treatment at Sichuan Cancer Hospital from April 2023 to March 2024 were retrospectively analyzed. All patients were treated with CyberKnife with 6 MV X-ray. According to the maximum diameter of brain metastases, the radiation prescription dose of brain metastases was adjusted. The tumor remission, recurrence, 6-month and 1-year overall survival (OS), local control (LC) of intracranial target lesions, progression-free survival (PFS), distant metastasis-free survival (DMFS) of intracranial brain metastases and adverse reactions were evaluated. According to the median biological dose, the survival difference between the groups was compared. Survival analysis was conducted by Kaplan-Meier method. Survival differences among different groups were analyzed by log-rank test.Results:A total of 63 eligible patients with brain metastases were enrolled, with a median age of 59 years (rang: 36-80 years). Among them, 47 patients were diagnosed with primary tumors originating from the lungs, 16 patients with primary tumors originating from other organs; 44 patients with single brain metastases, and 19 patients with 2-3 lesions, respectively. The median biological dose was 67.2 Gy (rang: 47.4-86.4 Gy), and the median single dose was 8 Gy/F (rang: 4-24 Gy/F). The follow-up was conducted until July 15, 2024. The median follow-up time for the entire group was 9 months (rang: 2-15 months). Among the 87 target lesions treated with CyberKnife, 11 patients corresponding to 14 target lesions experienced local recurrence. And the 6-month and 1-year LC rates were 92.5% and 70.9%, respectively. Ten patients corresponding to 16 target lesions died. And the 6-month and 1-year OS rates were 92.7% and 74.8%, respectively. Thirty-five patients corresponding to 50 target lesions experienced disease progression. And the 6-month and 1-year PFS rates were 64.3% and 25.5%, respectively. Thirty-three patients corresponding to 48 target lesions showed distant metastasis outside the target lesions, with a 6-month DMFS of 67.0% and a 1-year DMFS of 33.9%. Group comparison showed that 43 target lesions in the group receiving ≤67.2 Gy irradiation and 44 in the group receiving >67.2 Gy irradiation. The 6-month LC, OS, PFS, and DMFS rates between two groups were 89.8% vs. 97.7% ( P=0.127), 89.8% vs. 95.4% ( P=0.305), 65.4% vs. 68.5% ( P=0.514), 65.4% vs. 68.5% ( P=0.516), respectively. The 1-year LC, OS, PFS, and DMFS rates between two groups were 54.1% vs. 89.5% ( P=0.003), 67.3% vs. 82.9% ( P=0.219), 19.2% vs. 32.7% ( P=0.370) and 23.3% vs. 33.0% ( P=0.533). During the follow-up, only 2 patients (3.2%) were found to have grade 1-2 radiation-induced brain injury (asymptomatic brain injury) by MRI examination, and there were no other radiotherapy related adverse reactions. Conclusions:CyberKnife therapy is clinically effective for brain metastases, with mild adverse reactions. Increasing the tumor irradiation dose can improve local tumor control and is expected to further improve the OS of patients.

Objective:To present a set of clinically representative quality assurance (QA) test cases for stereotactic radiosurgery (SRT) plans of multiple intracranial metastases, in order to assess the plan quality and machine execution capabilities.Methods:Based on the clinical characteristics of multiple brain metastases, four groups of test cases with three target volumes (TVs), six TVs, nine TVs, and TVs near organs at risk (OARs) were designed. For these cases, SRT plans were developed, and plan quality was assessed using metrics including the Radiation Therapy Oncology Group conformality index (RTOG CI), gradient index (GI), homogeneity index (HI), and the volume of normal brain tissue receiving a dose of 24 Gy ( V24 Gy), which was defined as the volume enclosed by the 24 Gy isodose line around the Brain-PTV ( V24 Gy of Brain-PTV). Verification plans were generated for each test case, including the verification of point doses, planar doses (PD), and SRS MapCHECK (SMC) semiconductor matrix planar doses. Compared with the calculated result of the treatment planning system (TPS), the criteria for the γ analysis of planar doses were set at 1 mm/2% and 2 mm/2%. Results:For the four groups of test cases, the mean CI, GI, HI, and V24 Gy of Brain-PTV were 1.04±0.03, 3.79±0.40, 0.73±0.01 and (7.46±3.80) cm 3, respectively. The mean deviations of the point doses were 0.88%±0.98%, 1.47%±0.79%, 1.52%± 0.76%, and 1.17% ± 0.38%, respectively. The mean γ passing rates of the single fields for PDs were greater than 98% at 2 mm/2% and exceeding 96% at 1 mm/2%, and the mean γ pass rates of the SMC semiconductor matrix for PDs were 97.75% ± 2.31% and 99.33% ± 0.62%, at 1 mm/2% and 2 mm/2% respectively. Conclusions:The proposed QA test cases for SRT of multiple intracranial metastases allow for the effective assessments of the plan quality and machine execution capabilities and, thus, can assist various centers in clinical applications.