Objective To develop measurement of reference air kerma for192Ir sources with NE 2570 electrometer,2571 ion-chamber and machining measured holder.Methods The measuring holder was placed at the distance of 1 m from the walls,the floor and ceiling,the ion-chambet was insert into the oolymethyl methacrylate(PMMA)jig of the measuring holder,lhe optimum distance is 16 cm from the source centre to ionchamber centre.The source was transmitted by the afterloding system to the plastic pipe to measure reference air kerma of the source.According to calibration factors from60Coγrays and 250 kV X rays with air exposure to calculated the air kerma calibration factor,the air kerma calibration factor of 192Ir soHree was calculated bv60Co γ rays and the effective energy of the 250 kV X ray beam.The scatter correction factor was giverl by the shadow shield experiment for the wails,the floor,the air and the measuring holder,the correction factors were given for the attenuation of primary photons in air and the electrons entering the air cavity are mainly generated in the innerwall of the chamber by 1079 report in IAEA.Results Two measuring methods were used for192Ir source undersame environment condition,the ion-chatuber and well-type chamber values are 1.584×1011Bq and 1.561×1011Bq respectively,and the relative deviation from them is within 1.4%,Conclusions The air kerma measurement of 192Ir source the ion-chamber with is not depended on the source geometry(point seurce,line source etc),the size.and the material of shell,the shape,the quality of materials and the size of the chamber.The uncertainty error of the air kerma is lessin comparison to the air exposure.

Objective To facilitate activity measurement by using the thimble ionization chamber in hospitals,to obtain air kerma scatter correction factor of medical afterloading of 192Ir source by developing an available and convenient calculation method.Methods According to International Atomic Energy Agency (IAEA) 1079 Report to calculate the scatter correction factor of 192 Ir source,to measure air kenna of 192Ir source with and without lead shield using thimble ionization chamber.Simulation measurement conditions were used to calculate scatter correction factor of 192Ir source and comparison was made between experimental results and literature records.At the same time,the different ionization chamber models were simulated at different room sizes to obtain scattering correction factor of 192 Ir source.ResultsComparison was made between the simulation scatter correction factors of 192Ir source and experiment by the shadow shield,and the relative deviation was 0.8%.The deviation of the 192 Ir activity calculated according to the simulated scatter correction factor and measured by well type ionization chamber was 2.4%.By comparison between the calculated results by using two kinds of spherical ionization chamber and those ones deduced by IAEA 1079 Report,the relative deviations ranged within 0.3%-0.4%.Five different types of thimble ionization chamber and different room sizes were simulated and calculated by MC simulation,with the relative deviation within 3%.Conclusions Monte Carlo simulation method for calculating afterloading 192 Ir source's scatter correction factor is feasible,and this method is convenient for use in the thimble chamber for brachytherapy QA work in the hospital.

Objective To study the method of measuring air kerma strength of afterloading units with 192Ir source by using well type ionization chamber.MethodsThe air kerma strength of 30 afterloading units with 192Ir source was measured using 2000A electrometer and 1000 plus well type ionization chamber,and apparent activity of the source was calculated with the air kerma strength and apparent activity conversion factor.The measured activity of the source was compared with the original value of the source provided by the manufacturer,and the relevant deviation should be within ± 5%.Results Theair kerma strength of afterloding units with 192Ir sources was tested.The relevant deviation of the measured activity and the original value was within -0.1%-4.4%.Conclusions The measurement method with a well type ionization chamber is convenient and highly accurate which can be used for the test of quality control in hospitals.

Objective To explore the measurement method of the treatment dose of the patient with Diode for photon beam in radiotherapy,and to validate the treatment dose by comparing with the treatment planning system (TPS).Methods Experiments of the reproducibility,dose rate dependence,non-linearity dose response,and calibration factor in 60Co γ and 6 MV X beams were carried out with Diode on the surface of solid phantom and in water phantom.According to the needs of clinic treatment,different conditions were chosen to observe the dose changes with the angle of incidence,energy response,distance of source to skin,field size,wedge angle,block and tray using ionization chamber and water phantom.The Diode was placed on the surface of the solid phantom to obtain the correction factors.The doses of the chest,abdomen,and head and neek were verified with the Alderson phantom and Diode.Diode doses of the pelvis,head and neck at 14 points on the patient were measured.Results The Diode was irradiated at the points of the Alderson phantom,such as AP,RL and LL of the pelvis,with and without wedges,RL and LL junction of the neck and chin,with and without mask,the maximum relative deviation of doses was within ± 3% between Diode and TPS.The Diode was placed in different locations on the patient,including chest,abdomen and head and neck.The relative maximum deviation of doses was within ±5% between Diode and TPS.Conclusions The Diode method is reliable for measuring the exposure doses of the patient in radiotherapy.

To investigate the effects of Xinji' erkang (XJEK), a compound Chinese herbal medicine, on isoproterenol-induced ventricular remodeling in mice.

Colorectal serrated lesions are a group of polyps/adenomas with serrated architecture, including hyperplastic polyp, sessile serrated lesion and sessile serrated lesion with dysplasia, traditional serrated adenoma, and unclassified serrated adenoma. Sessile serrated lesion and traditional serrated adenoma are precursors of serrated lesions progressing to colorectal cancer. Serrated lesions are characterized by genetic (BRAF or KRAS gene mutations) and epigenetic (CpG island methylator phenotype) alterations that synergistically drive colorectal mucosa to develop polyps or adenomas, and with malignant transformation into colorectal cancer. The complexity of serrated lesion makes it difficult to diagnose, easy to miss diagnosis and has a high malignant rate. This article reviewed the advances in research on colorectal serrated lesions from the aspects of endoscopic, pathological and molecular features.

OBJECTIVE: To determine the incidence of surgical site infection (SSI) after abdominal surgery and to further evaluate the related risk factors of SSI in China. METHODS: The multicenter cross-sectional study collected clinical data of all adult patients who underwent abdominal surgery from May 1, 2018 to May 31, 2018 in 30 domestic hospitals, including basic information, perioperative parameters, and incisional microbial culture results. The primary outcome was the incidence of SSI within postoperative 30 days. SSI was classified into superficial incision infection, deep incision infection, and organ/gap infection according to the US Centers for Disease Control and Prevention (CDC) criteria. The secondary outcome variables were ICU stay, postoperative hospital stay, total hospital stay, 30-day mortality and treatment costs. Multivariate logistic regression was used to analyze the risk factors of SSI. RESULTS: A total of 1666 patients were enrolled in the study, including 263 cases of East War Zone Hospital of PLA, 140 cases of Affiliated Hospital of Qingdao University, 108 cases of The First Affiliated Hospital of Nanchang University, 87 cases of Central War Zone Hospital of PLA, 77 cases of West China Hospital, 74 cases of Guangdong General Hospital, 71 cases of Chenzhou First People's Hospital, 71 cases of Zigong First People's Hospital, 64 cases of Zhangjiagang First People's Hospital, 56 cases of Nanyang City Central Hospital, 56 cases of Lanzhou General Hospital of Lanzhou Military Command, 56 cases of Shandong Provincial Hospital, 52 cases of Shangqiu First People's Hospital, 52 cases of People's Hospital of Xinjiang Uygur Autonomous Region, 48 cases of The Second Xiangya Hospital of Central South University, 48 cases of Chinese PLA General Hospital, 44 cases of Affiliated Hospital of Xuzhou Medical University, 38 cases of Hunan Province People's Hospital, 36 cases of Dongguan Kanghua Hospital, 30 cases of Shaoxing Central Hospital, 30 cases of Northern Jiangsu People's Hospital, 29 vases of The First Affiliated Hospital of Zhengzhou University, 27 cases of General Hospital of Tianjin Medical University, 22 cases of Zigong Fourth People's Hospital, 21 cases of The Second Hospital of University of South China, 18 cases of Tongji Hospital, 15 cases of Nanchong Central Hospital, 12 cases of The 901th Hospital of PLA, 11 cases of Hunan Cancer Hospital, 10 cases of Lanzhou University Second Hospital. There were 1019 males and 647 females with mean age of (56.5±15.3) years old. SSI occurred in 80 patients (4.8%) after operation, including 39 cases of superficial incision infection, 16 cases of deep incision infection, and 25 cases of organ/interstitial infection. Escherichia coli was the main pathogen of SSI, and the positive rate was 32.5% (26/80). Compared with patients without SSI, those with SSI had significantly higher ICU occupancy rate [38.8%(31/80) vs. 13.9%(220/1586), P<0.001], postoperative hospital stay (median 17 days vs. 7 days, P<0.001) and total hospital stay (median 22 days vs. 13 days, P<0.001), and significantly higher cost of treatment (median 75 000 yuan vs. 44 000 yuan, P<0.001). Multivariate analysis showed that male rise(OR=2.110, 95%CI:1.175-3.791, P=0.012), preoperative blood glucose level rise(OR=1.100, 95%CI: 1.012-1.197, P=0.026), operative time (OR=1.006, 95%CI:1.003-1.009, P<0.001) and surgical incision grade (clean-contaminated incision:OR=10.207, 95%CI:1.369-76.120, P=0.023; contaminated incision: OR=10.617, 95%CI:1.298-86.865, P=0.028; infection incision: OR=20.173, 95%CI:1.768-230.121, P=0.016) were risk factors for SSI; and laparoscopic surgery (OR=0.348, 95%CI:0.192-0.631, P=0.001) and mechanical bowel preparation(OR=0.441,95%CI:0.221-0.879, P=0.020) were protective factors for SSI. CONCLUSIONS The incidence of postoperative SSI in patients with abdominal surgery in China is 4.8%. SSI can significantly increase the medical burden of patients. Preoperative control of blood glucose and mechanical bowel preparation are important measures to prevent SSI.
Abdomen ; surgery ; Adult ; Aged ; China ; Cross-Sectional Studies ; Female ; General Surgery ; statistics & numerical data ; Humans ; Male ; Middle Aged ; Operative Time ; Postoperative Complications ; prevention & control ; Preoperative Period ; Retrospective Studies ; Risk Factors ; Surgical Wound Infection ; prevention & control