Objective To study the difference of image quality and radiation dose between different exposure modes with full-field digital mammography (FFDM).Methods The Fluke18-220mammographic phantom was exposed by FFDM system with different exposure modes at automatic exposure control ( AEC ) ,including contrast mode,standard mode and dose mode,and the exposure factors and radiation dose were recorded.The images on monitor with the best window width and window level were read by four independent radiologists.The images of specks groups,nylon fibers and masses was assessed by the four experienced readers at the criterion of American College of Radiology.Results The detection of specks groups,nylon fibers and masses were statistically different at the contrast mode and standard mode (F =41.321,P ＜ 0.05),further at the contrast mode and dose mode.The detection of specks groups、nylon fibers and masses were not statistically different( P ＞ 0.05 ) at standard mode and dose mode,but the radiation doses were different.The ESD at standard mode and dose mode was 4.5 and 3.15 mGy,respectively.The AGD of standard mode and dose mode was 1.18 mGy and 0.78 mGy,respectively.Conclusions The standard mode and dose mode of FFDM might be fit for most patients,especially at the dose mode.Contrast mode of FFDM should be strictly controled in use.

Objective To compare imaging quality and radiation dose of different anode filter combination for full-field digital mammography.MethodsThe image of FLUKE NA 18-220 phantom were taken at full-field digital mammography (FFDM),system with Mo/Mo,Mo/Rh,Rh/Rh anode/filter combination by automatic exposure control,record the exposure factors and doses.The images on monitor with the best window width and window level were read by 4 independent radiologists,the images of specks groups,nylon fibers and masses was assessed by the 4 experienced readers at the criterion of American College of Radiology 1999 mammography quality control manual.Statistical analysis was performed using analysis of variance.ResultsThe nylon fibers scores of Mo/Mo,Mo/Rh and Rh/Rh were 5.50 ± 2.12,4.50 ± 1.85 and 4.38 ± 1.38 ; the specks groups scores of Mo/Mo,Mo/Rh and Rh/Rh were 5.38 ± 1.98,4.25 ± 1.56 and 4.38 ± 1.38;the masses scores of Mo/Mo,Mo/Rh and Rh/Rh were 5.38 ± 1.98,4.38 ±1.68 and 4.25 ± 1.56,the detection of specks groups,nylon fibers was not statistically significant ( F =4.56 and 4.32,P ＞ 0.05 ),but the detection of masses was statistically significant ( F =36.65,P ＜ 0.05).The radiation doses were different,the entrance surface dose (ESD) and average glandular dose (AGD) of Rh/Rh were (5.11 ± 1.89) and ( 1.08 ± 0.13 ) mGy,the ESD and AGD of Mo/Mo were (6.66 ± 2.33 )and ( 1.29 ± 0.38 ) mGy,the ESD and AGD of Mo/Rh anode/filter combination were (5.67 ± 2.02) and ( 1.29 ± 0.38) mGy.ConclusionsThe radiation dose of Rh/Rh and Mo/Rh anode/filter combination of FFDM were lower,and the imaging was clear,so Rh/Rh and Mo/Rh anode/filter combination of FFDM prefer to mostly patients,especially when the thinkness is large,Rh/Rh anode/filter combination is preferred,because the kV values was higher,the penetration of X-ray was stronger.The Mo/Mo anode/filter combination was used when the needs of high-resolution,because the detection of masses of it was better.

OBJECTIVE： To prepare β-sitosterol （shorted fo r “Sit”） and its deri vatives from the fruit of Sorbus pohuashanensis，and to investigte their antidepressant activities. METHODS ：Using the fruit of S. pohuashanensis as raw material ， extracted with 75％ ethanol and 20％KOH solution ，Sit was obtained after extraction and crystallization. C 3 hydroxyl group of Sit was used as the structural modification site ，CH2Cl2 was used as the reaction solvent ，DMAP was used as catalyst ，EDCI was used as dehydrating agent ，4 kinds of organic acids （salicylic acid ，2-tetrahydrofuranic acid ，phenylalanine，sorbic acid ）were added to make the carboxylation reaction to produce ester derivatives Sit-S ，Sit-T，Sit-P and Sit-Sr. The chemical structure of its derivatives were elucidated by IR and NMR. The tail suspension test and the forced swimming model were used to preliminarily explore the antidepressant active components of Sit and 4 kinds of derivatives ；tail suspension test and the spontaneous exercise capacity test were used to screen effective dose of the compounds with antidepressant active. The compound was used alone or in combination with agomelatin [ 40 mg/kg，5-hydroxytryptamine（5-HT）and 5-HT 2C receptor antagonist] ，haloperidol [ 0.2 mg/kg，non-selective D2 receptor antagonist] and bicuculline [ 4 mg/kg，competitive γ-aminobutyric acid（GABA）antagonist]，respectively. Sixty minutes after intraperitoneal injection ，tail suspension test was performed. The levels of 5-HT，dopamine（DA）and GABA in brain tissues of mice were detected by ELISA. The blank control group was given intraperitoneal injection of 10％ propylene glycol solution. RESULTS：By spectrum technology ，the corresponding ester compounds were synthesized by the reaction of Sit with four kinds of organic acids. Among Sit and its four derivatives ，the immobility time of Sit-S group was the shortest in tail suspension test and forced swimming test ，which was significantly shorter than that of blank control group （P＜0.05）. Screening results of Sit-S showed that the effective antidepressant dose was 4 mg/kg， ＊ and it did not affect the spontaneous activity of mice compared with the blank control group （P＞0.05）. With this dose ，Sit-S could significantly shorten the immobility time of mice in tail hua1666@163.com suspension test （P＜0.01），and can s ignificantly increase the ·64levels of 5-HT，DA and GABA in the brain tissue of mice （P＜0.05 or P＜0.01），but its effect can be reversed by agomelatine ， haloperidol and bicuculline to different extent. CONCLUSIONS ：Sit salicylate derivatives Sit-S exhibits good antidepressant activity，and its mechanism of action may be mediated by increasing the levels of 5-HT，DA and GABA.