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Objective To measure the body surface dose under different confinations of additional filters,tube voltage and tube current and discuss the lowest amount of different additional filters,tube voltage and tube current combination for crib side X-ray radiation dose while the quality of the image is guaranteed.Methods Japan Shimadzu wireless tablet mobile DR machine and Dutch Artinis CDRAD 2.0 phantom were used.The tube voltage and tube current for children's crib side X-ray normal work were 50 kV and 1.40 mAs to get the image quality figure inverse (IQFInv),respectively.Totally four filter combinations of 1 mm A1,2 mm A1,1+2 mm A1 and 0.3 mm Cu were added to the opening of collimator system by mobile DR machine.Phantom was shot by respectively combination of 50,66,83 and 100 kV tube voltages and different tube currents.All images to get the IQFInv value,Pearson correlation and regression analysis of the influence of tube voltage and current on IQFInv value were analyzed.The IQFInv value of the additional filter corresponds to the image quality of normal work.The combination of the additional filter with the tube voltage and the tube current was also found.Swedish RTI Barracuda diagnostic level dosimeter was used to measure the entrance surface dose of these combinations after filtration,20 times for each group.Results Comparisons among different filters,tube voltage and tube current combination with quality of daily work images:the tube voltage was positively correlated with IQFInv value in the test range(r=0.49,P＜0.05),and tube current was positively correlated with IQFInv value (r=0.36,P＜0.05).As the additional filters increase,it required greater tube current to acquire the desired value of images.Meanwhile,greater additional filters would increase the difference of IQFInv of tube voltage at each level.Comparisons among different filters,tube voltage and tube current combination with daily shooting dose,and after using additional filters,entrance surface dose changed from (30.58±0.21)to (10.49±0.09) μGy.There is a significant difference between each group (t=-15.306-514.585,P＜0.05).All additional filters effectively reduced entrance surface dose.Meanwhile,as the filter and tube voltage increased,entrance surface dose showed a more significant reduction.However,when the tube voltage exceeded 83 kV,all entrance surface dose of additional filters showed an increasing trend.Conclusions Additional filter is an effective method to reduce the crib side X-ray entrance surface dose.Under the premise of ensuring image quality,additional filter with high atomic number and second high kilovolt tube voltage with paired tube current is the best condition for crib side X-ray.
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Objective To observe characteristics of the activity in resting brain of asymptomatic reflux esophagitis (RE) patients,and explore the role of default network in the pathogenesis of asymptomatic RE.Methods Functional magnetic resonance imaging (fMRI) was performed to scan the brains of 15 asymptomatic RE patients,15 symptomatic RE patients and 15 healthy volunteers under no-mission-stimulation state.With fractional amplitude of low frequency fluctuation (fALFF),characteristics of the strengthened and weakened regions of asymptomatic RE patients,symptomatic RE patients and healthy individuals were compared and analyzed.SPM 5 was applied for data preprocessing.Single-sample t test was performed to observe the noticeable active regions of each group under resting state,and then double-sample t test was used to compare the characteristics of active regions of the entire brain between asymptomatic RE patients and symptomatic RE patients or healthy individuals.Results Under resting state,the active brain regions of asymptomatic RE patients,symptomatic RE patients and healthy individuals were similar.The activity of only small part of brain regions in visceral sensory processing relevant networks changed.There was no significant difference in the active regions of default network under resting state between asymptomatic RE patients and healthy individuals.Compared with symptomatic RE patients,fALEF decreased at right central sulcus cover,right superior temporal gyrus,right insula,right transverse temporal gyrus,right postcentral gyrus,superior temporal gyrus and temporal pole (X=50,Y=-6,Z=12,t=2.7874,P＜0.01).Conclusion The difference in characteristics of activity in default network under resting state may play an important role in the pathogenesis of asymptomatic RE.
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Objective To label rat bone marrow mesenchymal stem cells with superparamagnetic iron oxide (SPIO) and to explore the tropism of BMSCs for hepatocellular carcinoma cells after transplantation in vivo. Methods BMSCs from bone marrow of Sprague-Dawly (SD) rats were cultured isolated and purified, Labeled BMSCs was achieved using Feridex. Twenty-four hepatocellular carcinoma models of SD rats were induced two weeks before tmnsplantation. The models were divided into three groups in random: the labeled BMSCs and unlabeled BMSCs were transplanted respectively into the rat's livers of experimental group (n = 12) and control group A(n =6) via spleens, and no transplant was done for control group B (n =6). MR imaging was performed to monitor the transplanted cells after 1,3,7,14 d using 1.5 T MR system. Signal intensity ratio (SI/SI*) between tumor and hepatic tissue on T_2 * WI were measured and compared by one-factor analysis of variance. After MR imaging, Prussian blue staining was performed. MR imaging findings were compared with histological sections. Results Prussian blue staining confirmed the labeling efficiency of BMSCs was above 90%. SI/SI* of experimental group before and 1, 3, 7, 14 d after transplantation were 3.18±0.21,1.98±0.20,2.38±0.28,2.70±0.25 and 3.16±0.24 respectively. Following transplantation of BMSCs, signal intensity decrease was found in hepatocellular carcinoma of experimental group(F =56.65,P <0.05) and low signal change decreased gradually and disappeared at two weeks after transplantation, while no remarkable low signal change was seen in the control group by T_2 * WI (P > 0.05). A large number of Prussian blue staining positive cells were found in hepatocellular carcinoma in experimental group. Histological section with Prussian blue staining had a good correlation with the signal intensity changes on MR images at different time. Conclusion BMSCs display significant tropism to hepatocellular carcinoma and may be an ideal gene therapy vehicle against hepatocellular carcinoma.
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Objective To establish a stable and feasible animal model of acute cerebral infarction,and to evaluate it with functional magnetic resonance imaging and pathology.Methods Twenty-five S-D rats were randomly divided into five groups,and there were 5 rats in each group.Rats in group A were sham-operated for control study.Unilateral middle cerebral artery occlusion(MCAO) was performed with improved thread in group B,C,D,E and were enrolled for MRI and MRS study at 3,6,12,24 hours after MCAO.All rats were examined by 1-hydrogen magnetic resonance spectroscopy(~1H MRS).Two or three rats in each group were sacrificed for 2,3,5-triphenyltetrazolium chloride(TTC) staining of the brain and two rats for pathological examination after MRS.Results Rats in group A showed no change in brain on ~1 H MRS or pathological study.~1H MRS of the rat brains after right MCAO showed a decrease of N-acetyl-aspartate(NAA),an increase of Lactate(Lac) in all groups.There was no significant change of Choline(Cho) and Creatine(Cr) peaks onrats in group B,C,D.The peaks of Cho and Cr were slightly dropped in group E.Conclusion The acute regional cerebral ischemic model in rats made by our approach is stable and reproducible,and it is suitable for evaluation and study with functional magnetic resonancespectroscopy accurately and sensitively.
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Objective To preliminary investigate the brain areas associated with Chinese when they speak Chinese . Methods In order to determine the neural anatomic substrates employed in repeatedly speaking Chinese , 22 Chinese health volunteers were performed using blood oxygenation level dependent (BOLD) contrast functional magnetic resonance imaging (fMRI) on a 1.5T system .Results Our block-design fMRI studies have found many cortical areas that are associated with Chinese-English bilinguals. The cortical areas were shown as bilateral motor cortex , left anterior inferior frontal Gyrus , left anterior insula , bilateral superior temporal gyrus and bilateral cerebellum. Conclusion BOLD fMRI can reveal cortical areas that are associated with Chinese when they speak Chinese ,and it is a powerful utility to investigate language.