Objective:To establish a radiotherapy treatment planning process of high ventilation functional lung avoided (HVFLA) for thoracic tumors based on 4D-CT lung ventilation functional images and determine the treatment planning strategy of HVFLA radiotherapy, and so as to provide support for the clinical trials of HVFLA radiotherapy in thoracic cancer patients.Methods:A deep learning-based 4D-CT lung ventilation functional imaging model was established and integrated into the radiotherapy treatment planning process. Furthermore, ten thoracic cancer patients with 4D-CT simulation positioning were retrospectively enrolled in this study. The established model was used to obtain the 4D-CT lung ventilation functional imaging for each patient. According to the relative value of lung ventilation, the lung ventilation areas are equally segmented into high, medium and low lung ventilation and then imported them into Pinnacle 3 treatment planning system. According to the prescription dose of target and dose constraints of organ at risks (OARs), the clinical and HVFLA treatment plans were designed for each patient using volumetric modulated radiotherapy technique, and each plan should meet the clinical requirements and adding dose constraints of high ventilation functional lung for HVFLA plan. The dosimetric indexes of the target, OARs (lungs, heart and cord) and high functional lung (HFL) were used to evaluated the plan quality. The dosimetric indexes included D2, D98 and mean dose of target, V5, V10, V20, V30 and mean dose of lungs and HFL, V30, V40 and mean dose of heart, and D1 cm 3 of cord. Paired samples t-test was used for statistical analysis of the two groups of plans. Results:The target and OARs of the clinical plan and HVFLA plan meet the clinical requirements. The HVFLA plan resulted in a statistically significant reduction in the mean dose, V5, V10, V20, and V30 of the high functional lung by 1.2 Gy, 5.9%, 4.2%, 2.6%, and 2.3%, respectively ( t=-8.07, 4.02, -6.02, -7.06, -6.77, P<0.05). There was no statistical difference in the dosimetric indexes of lungs, heart and cord. Conclusions:We established the treatment planning process of HVFLA radiotherapy based on 4D-CT lung ventilation functional images. The HVFLA plan can effectively reduce the dose of HFL, while the doses of lungs, heart and cord had no significant difference compared with the clinical plan. The strategy of HVFLA radiotherapy planning is feasible to provide support for the implementation of HVFLA radiotherapy in thoracic cancer patients.

Objective:To verify the feasibility of using Elekta accelerated go live (AGL) standard process for the acceptance of multiple accelerators.Methods:The beams of three accelerators were adjusted by PTW Beamscan three-dimensional water tank to reach the AGL standard. Dose verification was performed for three accelerators that met AGL standards. A simple field test example from Cancer Hospital Chinese Academy of Medical Sciences was used to compare the MapCheck 3 surface dose measurement results with the surface dose calculated by the same accelerator model. Images of 10 patients including head and neck, esophagus, breast, lung and rectum were randomly selected. volumetric-modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) treatment techniques were used for planning design, and the measured dose of ArcCheck was compared with the planned dose calculated by the same accelerator model. One-way ANOVA was used to statistically analyze the passing rates of two-dimensional and three-dimensional dose verification.Results:The 6 MV X-ray percentage depth dose at 10 cm underwater (PDD 10) of three accelerators was 67.45%, 67.36%, 67.47%, and the maximum deviation between the three accelerators was 0.11%. The 6 MV flattenting filter free (FFF) mode X-ray PDD 10 was 67.33%, 67.20%, 67.20%, and the maximum deviation between the three accelerators was 0.13%. All required discrete point doses on each energy 30 cm×30 cm Profile spindle of the three accelerator X-rays deviated less than ±1% from the standard data. Absolute γ analysis was performed on the results of MapCheck 3 two-dimensional dose matrix validation. Under the 10% threshold of 2 mm/3% standard, the average passing rate of the test cases in Cancer Hospital Chinese Academy of Medical Sciences was above 99%, and the difference was not statistically significant ( P>0.05). Absolute γ analysis was performed on the ArcCheck verification results. Under the 10% threshold, the pass rate of 2 mm/3% was all above 95%, the maximum average passing rate of the three accelerators with different energy and different treatment techniques was 0.28% (6 MV, VMAT), 0.19%(6 MV FFF, VMAT), 0.56% (6 MV, IMRT) and 0.05% (6 MV FFF, IMRT), and the difference was not statistically significant ( P>0.05). Conclusion:Compared with traditional accelerator acceptance process, the acceptance time of each accelerator is shortened by 4-6 weeks by using the AGL standard process, and the radiotherapy plan of patients can be interchangeably executed among different accelerators.

Objective:To obtain hepatitis B virus capsid-like particles (CLPs) displaying B-cell linear epitopes of SARS-CoV-2 spike protein and evaluate their immunogenicity.Methods:Four recombinant plasmids expressing fusion proteins (M1-HBc, S1-57-HBc, S14P5-HBc and S21P2-HBc) were constructed by separately replacing codon of alanine at position 80 of hepatitis B virus core protein (HBc) with four genes coding for four B-cell linear epitopes (M1, S1-57, S14P5 and S21P2). These four recombinant proteins were expressed in E. coli BL21 Star (DE3) strains. The expression products were identified using SDS-PAGE, Western blot and native agarose gel electrophoresis (NAGE). CLPs were purified by sucrose density gradient ultracentrifugation, verified for antigenicity by Western blot and used to immunize BALB/c mice. Serum antibody titers were detected by ELISA. Results:The recombinant fusion proteins M1-HBc and S1-57-HBc self-assembled into M1-CLP and S1-57-CLP. The titer of antibody against S1-57 polypeptide in S1-57-CLP-immunized mouse serum approached 1∶1 000 000.Conclusions:Hepatitis B virus CLPs displaying SARS-CoV-2 M1 or S1-57 linear epitopes are successfully expressed in a prokaryotic system and purified. S1-57-CLP has good immunogenicity. This study provides a new idea for the development of novel diagnostic reagents and vaccines for SARS-CoV-2.

Clarifying the applicability （indications or contraindications） of traditional Chinese medicine （TCM） dietary regimens to different syndromes is a guarantee for the rational application and safety of TCM dietary therapy. By considering evidence from ancient literature， modern research and experts' experience， the Grading System for Syndrome Suitability of Dietary Therapy in TCM （GRADE-SSD） has been constructed. According to the currently available highest-quality evidence， GRADE-SSD classified the applicability of TCM dietary therapy to various TCM syndromes into 2 categories and 4 grades： "definitely" applicable/contradicted （Grade A）， "very likely" applicable/contradicted （Grade B）， "possibly" applicable/contradicted （Grade C）， and insufficient evidence to determine （Grade D）. When applying， first， systematically search the currently available ancient books and clinical research evidence. For different types of evidence （ancient TCM books， randomized controlled trials， observational studies， and meta-analyses）， use the prescribed tools to evaluate the quality of the evidence， and then determine the applicability level of TCM syndromes of dietary therapy based on the principle of "taking the highest" quality. If there is a lack of direct evidence， GRADE-SSD supports a downgraded evaluation based on indirect evidence of "similar prescriptions". When there is a lack of ancient books and clinical research， the GRADE-SSD plan can evaluate the quality of evidence from peer consensus or expert opinions for the applicability level of TCM syndromes of dietary therapy. Based on the requirements for the safety of TCM dietary therapy， when there is both "applicable" and "contradicted" evidence， it should be considered as "contradicted" evidence. GRADE-SSD also provides an evidence certainty update plan based on new evidence in the future. The evaluation results of GRADE-SSD can provide a basis for setting inclusion/exclusion criteria in clinical trials of TCM dietary therapy and stating the applicability of each syndrome in the labels of dietary therapy products.

Objective:To explore the construction of a competency-oriented off-campus practice training system for master of public health (MPH).Methods:Through literature review and analysis on domestic and foreign MPH degree training models, a comprehensive and feasible MPH off-campus practice training system was designed innovatively.Results:The construction of a "4+N+Comprehensive Evaluation" practice system for MPH programs with a practice duration of more than 2 years has been explored by high-level public health talent training demonstration base of Sun Yat-sen University-Guangzhou CDC. "4" represents practice-based teaching, professional practice, participation in public health project management, and research for the training of MPH in terms of theory, practice, management and research anility of public health. "N" represents expanded practice to train MPH with comprehensive competence and professional spirit," and comprehensive evaluation is used to assess the training effect.Conclusion:A competency MPH off-campus practice system of "4+N+Comprehensive Evaluation" has been established for the training of high-level public health professionals in new era.

Objective On the premise of meeting the image quality requirements of simulated location for pediatric radiotherapy,the simulated localizable CT parameters are optimized through phantom scanning to reduce the radiation dose.Methods CatPhan700 phantom was used to simulate the child's body,Philip 24-row large-aperture spiral simulated localizable CT was performed,and the CT images were obtained by scanning the phantom at different mAs and tube voltages.The mAs range was set at 60-400 mAs,the scanning was performed every 20 mAs interval,and the kV was set at 80,100,and 120 kV.Image evaluation was carried out using parameters such as image noise(N10 and mean SD),uniformity,low contrast resolution,high contrast resolution,and the stabilities of HU values of Air,Acrylic,50%bone,LDPE,20%bone,Teflon,Polystyrene,DelrinTM,Lung,PMP and Water.The CTDIVol and DLP automatically calculated by the simulated localizable CT system were read to evaluate the radiation dose.Results At 100 kV,as mAs increased,both CTDI and DLP showed upward trends,and the fitting results were linear correlated,with slopes of 0.034 5 and 0.932 4.Image noise was decreased nonlinearly with the increasing mAs.When mAs increased from 60 to 140 mAs,N10 decreased from 0.25%to 0.14%,and SD reduced from 3.74 HU to 2.54 HU.When mAs reached 180 mAs or higher,N10 fluctuated between 0.1%and 0.12%,the mean SD fluctuated between 2.0 and 2.5 HU,and the downward trends obviously slowed down.When mAs increased from 60 to 200 mAs,the low contrast resolution of the image dropped from 0.53 to 0.29.The image uniformity,high contrast resolution and HU values of different substances were less affected by mAs.The image quality of 100 kV and 200 mAs scanning was close to that of 120 kV scanning,but the image quality of 80 kV scanning failed to meet the clinical requirements.Conclusion In order to reduce the radiation dose as much as possible,the mAs should be set at 200 mAs when the tube voltage is set at 100 kV for a simulated cylinder with a diameter of 20 cm.In the actual simulation scanning for pediatric radiotherapy,the scanning parameters should be fine-tuned according to the phantom results and the actual physical characteristics of children to satisfy the optimization principle for radiation protection.

Objective Magnetic resonance simulator(MR Sim)is a novel type of simulation equipment utilized in radiotherapy.Acceptance testing is an essential quality assurance procedure prior to the clinical use of the MR Sim.The report provides the detailed procedures and result analysis of acceptance testing for an MR Sim.Methods The acceptance testing scheme was developed following the recently published AAPM TG284 report and the NCC/T-RT 002-2023 guidelines.Quality control equipments such as ACR(American College of Radiology)large phantom and geometric distortion measurement phantom were used for evaluating various aspects of the MR Sim,including the effectiveness of shielding,the functionality of imaging system,the image quality,the performance of radio frequency coils,the geometric accuracy of large field imaging,the precision of external laser markings,the couch movement accuracy,and the image transmission accuracy.Results The shielding effectiveness at a frequency of 150 MHz exhibited an average value of 105 dB.All of 8 image quality indices,namely geometric accuracy,slice position accuracy,slice thickness accuracy,image uniformity,artifact ratio,signal-to-noise ratio,high-contrast spatial resolution,and low-contrast resolution,fell within recommended tolerances.The maximum geometric distortion observed across a 25 cm field of view was less than 2 mm.The errors in external laser markings and couch movement accuracy were both less than 1 mm.The couch levelness was less than 1°.Both radio frequency coils and image transmission passed the required tests.Conclusion MR Sim is high-precision and complex.To ensure its precise application in radiotherapy,the acceptance testing for an MR Sim should be meticulously designed and executed following the established guidelines and accounting for its unique performance characteristics.

Objective:To evaluate the feasibility of using MRI-only simulation images for dose calculation of both photon and proton radiotherapy for nasopharyngeal carcinoma cases.Methods:T 1-weighted MRI images and CT images of 100 patients with nasopharyngeal carcinoma treated with radiotherapy in Cancer Hospital of Chinese Academy of Medical Sciences from January 2020 to December 2021 were retrospectively analyzed. MRI images were converted to generate pseudo-CT images by using deep learning network models. The training set, validation set and test set included 70 cases, 10 cases and 20 cases, respectively. Convolutional neural network (CNN) and cycle-consistent generative adversarial neural network (CycleGAN) were exploited. Quantitative assessment of image quality was conducted by using mean absolute error (MAE) and structural similarity (SSIM), etc. Dose assessment was performed by using 3D-gamma pass rate and dose-volume histogram (DVH). The quality of pseudo-CT images generated was statistically analyzed by Wilcoxon signed-rank test. Results:The MAE of the CNN and CycleGAN was (91.99±19.98) HU and (108.30±20.54) HU, and the SSIM was 0.97±0.01 and 0.96±0.01, respectively. In terms of dosimetry, the accuracy of pseudo-CT for photon dose calculation was higher than that of the proton plan. For CNN, the gamma pass rate (3 mm/3%) of the photon radiotherapy plan was 99.90%±0.13%. For CycleGAN, the value was 99.87%±0.34%. The gamma pass rates of proton radiotherapy plans were 98.65%±0.64% (CNN, 3 mm/3%) and 97.69%±0.86% (CycleGAN, 3 mm/3%). For DVH, the dose calculation accuracy in the photon plan of pseudo-CT was better than that of the proton plan.Conclusions:The deep learning-based model generated accurate pseudo-CT images from MR images. Most dosimetric differences were within clinically acceptable criteria for photon and proton radiotherapy, demonstrating the feasibility of an MRI-only workflow for radiotherapy of nasopharyngeal cancer. However, compared with the raw CT images, the error of the CT value in the nasal cavity of the pseudo-CT images was relatively large and special attention should be paid during clinical application.

Deep venipuncture catheterization is a routine and basic operation in the treatment of critically ill patients, and it is the most effective way to quickly correct the shock. Clinical B-ultrasound guided deep vein catheters can improve the success rate of puncture, but in the process of operation, the short axis needs to be replaced by the long axis. In the replacement process, the stability of the novice is insufficient, the positioning is difficult, and the operation time is too long. If only short axis puncture is used, it is impossible to know whether the current position of the puncture needle, and the puncture may be too deep and stray into the artery. The accuracy of the 45 degree angle of the injection point requires a very experienced operator. In view of the above shortcomings, doctors in the department of critical care medicine of Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine designed a B-ultrasound puncture equipment, which has obtained the National Invention Patent of China (ZL 2016 1 0571557.X). The device is composed of B-ultrasound probe fixing frame, sliding scale plate, simulation slide rule, puncture needle, sliding device. By sliding device the angle of the pinhole channel, it is conducive to the accurate positioning of the puncture target, optimizing the operation procedure, improving the puncture speed and accuracy, effectively reducing the occurrence of puncture complications, ensuring patient safety, reducing unnecessary waste of human and material resources. It can reduce the workload of medical staff and is worthy of clinical practice.
Humans ; Catheterization, Central Venous/methods* ; Ultrasonography, Interventional/methods* ; Ultrasonography ; Punctures/methods* ; Needles

Objective:This work aims to investigate the virulence features, spore formation and the resistance mechanisms of major sequence types (STs) of clinical Clostridium difficile isolates from nosocomial infectious diarrhea. Methods:Clostridium difficile isolates were prospectively collected from 816 loose stool samples of in patients with antibiotic associated diarrhea at the Beijing Friendship Hospital of Capital Medical University from September 2017 to September 2019. The main ST types ST81 (26 strains), ST8 (15 strains) and ST42 (14 strains) of C. difficile were used as experimental strains. The polymerase chain reaction (PCR) and enzyme-linked immunoassay (ELISA) were performed to detect toxin genes and toxin production of different C. difficile ST types, respectively. The count of the colony forming units (CFU) of the strains as conducted by using the brain-heart infusion (BHI) agar plates. The antimicrobial resistance patterns of the strains to eleven kinds of antibiotics were determined by agar dilution method. The antimicrobial resistance genes: gyrA, gyrB and ermB were amplified and sequenced from the stains. Mutations in the resistance genes were analyzed by sequencing. Measure data was compared by Kruskal Wallis Test, differences in the resistance rates in three group were compared using Fisher exact test. Results:ST81 strains were identified as the tcdA-tcdB+/ cdtA-cdtB-toxin type, ST8 and ST42 strains belonged to tcdA+tcdB+/ cdtA-cdtB-toxin type. The toxin production of ST42 strains (41.9) were higher than ST8 (2.4) and ST81 groups (0.83) (all P<0.001). The number of spore quantities of ST81, ST8 and ST42 strains were 494×10 5CFU/ml, 160×10 5CFU/ml and 166×10 5CFU/ml, respectively. The spore quantities of ST81 strains were much higher than that of ST81 and ST42 strains (all P<0.001). From the in vitro susceptibility test, 100% (26/26) ST81 strains were featured as multi-drug resistant (MDR), and they were resistant to moxifloxacin, ceftriaxone, erythromycin and clindamycin. The resistance rates of ST8 strain to moxifloxacin, erythromycin and clindamycin were 9/15, 11/15 and 11/15, respectively. ST81 strains had higher resistance rates to moxifloxacin, clindamycin and erythromycin, compared to ST8 strains ( P=0.001, P=0.005 and P=0.005). All ST42 strains were susceptible to ceftriaxone and 3/14 ST42 strains were resistant to moxifloxacin. ST81 strains had higher resistance rates to ceftriaxone and moxifloxacin than the ST42 strains (both P<0.001). The positive rate of ermB in ST81 strains (100%, 26/26) were higher the ST8 strains (11/15) ( P<0.005). Amino acid mutation analysis showed that ST81and ST8 stains had one amino acid substitution in both GyrA and GyrB, but the amino acid substitutions were different in GyrB between two ST types. ST81 strains had two point-mutations: Thr82 replaced by Ile in GyrA, and Asp426 replaced by Val in GyrB. ST8 strains had point-mutation: Thr82 replaced by Ile in GyrA; Asp426 replaced by Asn in GyrB. For ST42 strains, Thr82 was replaced by Ile in GyrA. Conclusions:ST81 and ST42 strains were MDR. ST81 had higher spore ability, whereas ST42 strains had more virulence. ST81 strains and most of ST8 strains had high level of fluoroquinolones resistance. It is important to supervise persistently these three ST genotypes to prevent further dissemination.