Radiation-induced cognitive impairment is hypothesized to occur because of dynamic interactions be -tween multiple cell types, including astrocytes, endothelial cells, microglia, neurons, and oligodendrocytes.Cur-rent researche indicates that radiation-induced changes include the decrease in hippocampus neurogenesis , altera-tions of neuronal functions , particularly synaptic plasticity , as well as the elevation of neuroinflammatory cytokines .

Objective To investigate the protective effects of ulinastatin(UTI)on ischemia-reperfusion(I/R)injury(SMIRI)of skeletal muscle in rats.Method Twenty-four male SD rats randomly were divided into three groups in equal number:control group(Group C)rats underwent anesthetization without ischemia;the ischemia-reperfusion injury group(Group I/R)rats underwent ischemia and reperfusion,0.5 ml normal saline (N.S)was infused upon extermal jngular vein prior to reperfusion;ulinstatin group(Group U)underwent ischemia and reperfusion,and 0.5 ml UTI(5×104 U/kg)Was infused at the same time.The skeletal muscle injury model was induced by a rubber band tourniquet applied to the left root of the hind limb for 4 hours and reperfusion for 4 hours.At the end of study,the expression of TNF-α mRNA of skeletal muscle was determined by reverse transcription-polymerase chain reaction(RT-PCR);enzyme-linked immun-osorbent assay(ELISA)were performed for plasma level of TNF-α;the plasma concentrations of lactate dehydrogenase(LDH),creatine kinase (CK),malondialdehyde(MDA),myeloperoxidase(MPO)activity and MDA in skeletal muscle were measured by colorimetry respectively.The oedema degree was quantified by calculating the wet/dry weight ratio of skeletal muscle.Structural changes of skeletal muscle were also observed histologically and ultrastructurally.The statistical difference was analyzed with One-way ANOVA by SPSS version 10.0 Software for windows.Results The level of plasma TNF-α,TNF-α mRNA expression in skeletal muscle in group I/R were significantly higher than those in Group C(P＜0.01),while those in Group U were significantly lower than those in Group I/R(P＜O.01).The plasma concentrations of LDH,CK,MDA and the MPO activity,W/D of skeletal muscle varied in those groups were likewise in comparinson between groups(P＜0.05).The histologic changes of skeletal muscle tissue under light and electronic microscopy were slingter in Group U than in group I/R.Conclusions UTI can inhibit the production of inflammatory factors and MDA,and suppress the MPO activity,showing protective effects against ischemia-reperfusion injury of skeletal muscle of rats.

Objective To realize independent 3D dose calculation for intensity-modulated radiotherapy (IMRT) by building a two-source beam model of medical linear accelerator combined with a collapsed-cone convolution/superposition (CCCS) algorithm.Methods Two-source beam models of medical linear accelerators (Varian and Elekta) were built to calculate the 3D dose distributions using the CCCS algorithm.Scp,percent depth dose,and off-axis dose distribution were compared with the scanning data of ion chamber to confirm the calculation model.Twelve intensity-modulated treatment plans from each accelerator (a total of 24 plans) were selected for comparison.The calculation results of treatment planning system (TPS) were independently validated,and further compared with the measurement results of detector matrix.Results The dose deviations at the center of rectangle fields were lower than 1%,the deviation between doses at the same position in the field was not higher than 1%,and the positional deviation in the penumbra region was not higher than 1 mm.Gamma analysis based on 3%/3 mm standard was used to compare the results calculated by detectors and TPS.The pass rates were higher than 90%.Conclusions The independent 3D dose calculation for IMRT based on two-source beam model combined with CCCS algorithm has been successfully set up.The comparison between regular field and IMRT plan indicates that this method and calculation model can be used for independent 3D dose calculation of clinical plan.

Objective The antioxidative activities of extracts from Undaria pinnatifida in vitrowere tested. Methods Using the assay system of peroxide value (POV), diphenyl picryl-hydrazyl (DPPH), the antioxidative activities of various extracts were studied and comparedwith VE and VC. Results Different extracts from Undaria pinnatifida showed antioxidativeactivities, and petroleum ether extract showed the highest free radical scavenging efficiency.Conclusion petroleum ether extract has stronger antioxidative effect than others.

Objective To establish a fast and accurate method for measurement of leaf position accuracy of dynamic multi-leaf collimator (MLC) using electronic portal imaging device (EPID) and EBT3 film dosimeter.Methods A Varian 6 MV accelerator was used with the gantry angle and the collimator angle fixed at zero degree.A total of 11 sliding window MLC fields were designed.Each field contained a group of strip fields with the same width.The width of a strip field ranged from 1 mm to 10 mm and the distance between two adjacent strip fields was 20 mm.The relationship between the width of the strip field (band width) and the full width at half maximum (FWHM) was calibrated using EPID and EBT3 as measurement tools.A field with a band width of 5 mm was designed in the same way and several MLC leaf deviations were made in different positions.EPID and EBT3 film dosimeter were used to analyze the leaf position accuracy.Results A good linear relationship between band width and FWHM was achieved when the band width was larger than 4 mm.The accuracy of band width,distance between peaks,and MLC leaf position were determined as ±0.2 mm,±0.1 mm,and ±0.1 mm by EPID and ±0.3 mm,±0.2 mm,and ± 0.2 mm by EBT3 film dosimeter,respectively.Conclusions This study provides a fast and accurate method for the measurement of MLC leaf position accuracy using EPID or EBT3 film dosimeter,which is helpful for quality assurance of MLC.

Objective To establish a quantitative evaluation of quality control image for the onboard imaging system of medical linear accelerator.Methods An MV planar image of electronic portal imaging device (EPID) is acquired by both Elekta iViewGT and Varian aS1000,and a kV planar image and cone-beam computed tomography (CBCT) images of CBCT are acquired by both Elekta X-ray volume imaging (XVI) and Varian On-board Imager (OBI).Phantoms used here included Las Vegas,TOR18FG,and Catphan504.A series of image quality indicators were evaluated by analyzing the images mentioned above using a quantitative method.Results A quantitative value was calculated to represent the contrast resolution of EPID.A modulation transfer function (MTF) to describe spatial resolution and a quantitative value representing contrast resolution were calculated for the kV planar image.As for the CBCT system,a series of quantitative results of noise,uniformity,CT value accuracy,and contrast resolution and a MTF were calculated to represent the performance of CBCT system.Conclusions Based on common phantoms,a complete set of quantitative methods to evaluate the image quality of EPID and CBCT has been developed,which could provide a very good reference for the establishment of quality control system for image-guided radiotherapy.

Objective To evaluate the Imaging diagnosis of SARS in death case.Methods 11 death patients of SARS in keeping with criteria from April to May 2003 were enrolled into the study. Imaging characteristics of chest x-ray film and CT in these patients were analysed.Results All cases were positive on chest X-ray film and CT,the lung shadows were marked.The extent of the pathological changes in lungs was 80%～90% in 6 cases and 90% above in 5 cases,multilobcs of bilateral lungs were involved in all cases.The lesions were diffuse spotty shadow or shaggy cloudy shadow in 8 cases,ground-glass opacification in one case and bronchogram structures could be seen.Conclusion Imaging findings in the cases with severe SARS mostly manifest as effusion,consolidation and interstitial inflammation in multilobes of bilateral lungs.

Objective: To study on the genomic stability of male workers engaged in e-waste dismantling area in Tianjin. Methods: In 2016, an e-waste dismantling area in Tianjin and an area 50 km away from the e-waste dismantling area (no e-waste or other chemical, industrial and agricultural pollution nearby) were selected as the study area and the reference area. Male residents of the study area and male farmers who planted vegetables, fruits, and crops in the reference area were selected as the exposed and reference group by using the convenient sampling method. The exposed group included 146 workers who engaged in e-waste recycling work more than 1 year. The reference group included 121 farmers who never engaged in e-waste recycling work. Questionnaires were used to collect information of all subjects. The semen and peripheral blood were also collected. Trace elements and polychlorinated biphenyl concentration in blood were detected. DNA damage in peripheral blood and sperm was detected, and gene expression was analyzed. DNA damage was assessed using tail DNA% (TDNA%), tail moment (TM) and olive tail moment (OTM) of comet assay. Results: The ages of the exposed group and the reference group were (33.6±12.1) and (33.9±11.9) years old, respectively. The proportions of subjects with exposure time of ≤3, 4-6, ≥7 years were 43% (63 cases), 26% (53 cases) and 21% (30 cases), respectively. The Pb and polychlorinated biphenyl(PCB) concentrations in the exposed group [(90.4±15.3) μg/ml and (101±30) ng/ml, respectively] were higher than those in the reference group [Pb and PCB concentrations were (60.2±8.9) μg/ml, and (2.5±1.4) ng/ml, respectively (both P values <0.05)]. The TDNA%, TM and OTM of peripheral blood and sperm in the exposed group were 5.9%±0.3% and 2.6%±0.90%, 0.93±0.16 and 0.51±0.20, 0.82±0.09 and 0.56±0.07, respectively, which were all higher than those in the reference group [TDNA%, TM and OTM of peripheral blood and sperm were 1.8%±0.2% and 1.9%±0.2%, 0.21±0.04 and 0.32±0.10, 0.19±0.03 and 0.20±0.08, respectively (all P values <0.001)]. The results of gene expression showed that 20 differentially expressed genes, including 13 up-regulated genes and 7 down-regulated genes, were detected in the exposed group compared with the reference group. Conclusion There are obvious DNA damage and DNA repair gene disorder in male workers of an e-waste dismantling area in Tianjin. The current operation mode brings potential health risks to workers.

Objective: To study on the exposure of polychlorinated biphenyl (PCB) contamination and DNA methylation in male employees in an e-waste dismantling area in Tianjin. Methods: In 2016, an e-waste dismantling area in Tianjin and an area 50 km away from the e-waste dismantling area (no e-waste or other chemical, industrial and agricultural pollution nearby) were selected as the study area and the reference area. Male residents of the study area and male farmers who planted vegetables, fruits, and crops in the reference area were selected as the exposed and reference group by using the convenient sampling method. A total of 60 subjects (30 in each of the exposed group and the reference group) were included. The peripheral blood (5 ml) of the study subject was collected, and the PCB concentration was detected. Eight independent subjects in the exposed group and the reference group were randomly selected by random number table method to detect the methylation level of the promoter region of all gene loci, and the mRNA transcript levels. Results: The PCB concentration in peripheral blood of the exposed group was higher than that of the reference group, and the difference was statistically significant (allP values <0.001). The methylation levels of the promoter region of the exposed group and the reference group showed obvious clustering, and 994 gene loci had different degrees of methylation. Compared with the reference group, there were 391 hypomethylation sites and 553 hypermethylation sites in the exposed group. The proportion of methylation sites in the high CpG-rich region was 59.2% and 48.1%, respectively. The mRNA level of the hypomethylated gene in the exposed group was higher (FAM131A, HBM), and the transcription level of the hypermethylated gene was lower (CAPN15, NFIC, SHISA5, FGF13, GRAMD1A, CLEC3B, LILRB2, DCAF7). The mRNA transcription levels of 10 genes above in the exposed group and the reference group were statistically significant (all P values <0.001). Conclusion The PCB concentration of peripheral blood in the exposed population of e-waste is high. PCB exposure changes the methylation level of specific genes and affects the mRNA transcription level of some genes.

Objective:To study the effect of occupational X-ray exposure on non-cancer diseases of radiation workers.Methods:The medical X-ray workers in Chongqing mumicipality were surved in 1980. In 2020, the previous 91 medical institutions distributed across 41 districts and counties of Chongqing continued to be selected as the survyed units, including 53 grade-A top-class hospitals. Using the method of prospective cohort study, the fifth follow-up survey was conducted for Chongqing′s medical X-ray workers and the control groups in 1980 with respect to their personal information, occupational radiation exposure, disease history and others. The incidence rate, relative risk ( RR) and 95% confidence interval of diseases in each system were analyzed. Results:There were 937 individuals in this cohort. So far, 359 cases of non-cancer diseases had been counted. Compared with the control group, the relative risk RR of cardiovascular system, ophthalmology and other unclassified diseases in the exposure group were 1.50, 2.03 and 2.64 ( χ2=5.97, 3.97, 4.25, P <0.05) , respectively. The adjusted confounding factors showed that the RR of the incidence rate of cardiovascular, ophthalmic and digestive diseases in the female exposure group was generally higher than that in the control group ( RR=2.33, 2.59, 7.55; χ2= 7.28, 4.17, 8.64, P < 0.05) , respectively. The RR of the incidence rate of cardiovascular and ophthalmic diseases in exposure group was generally higher than that in the control group among 25-29 year-old workers ( RR=2.26, 5.07; χ2 =8.22, 4.91, P < 0.05) , respectively. For compasion between the the accumulated dose groups, the incidence rate of cardiovascular system, ophthalmology and digestive system diseases in the exposure group was generally higher than that in the control group ( RR=1.86, 2.91, 3.59; χ2= 9.83, 8.21, 5.58, P < 0.05) , respectively. Conclusions:The non-cancer risk of X-ray workers exposed to long-term occupational exposure was increased, among which the risk of cardiovascular system, digestive system, ophthalmic diseases and others might be related to the occupational exposure.