Clinical Research Of Low X-ray Dosage Scanning Of Orbita By MDCT

ObjectiveTo evaluate the clinical value of low x-ray dosage scanning of orbita by MDCT and research feasibility and practicability of low x-ray dosage scanning technology for ophthalmic diseases.Material and method1,Study object98 patients joined in this study during july 2008 and december 2008,among which 58 were male,40 patients were femal.the average age was 34.8.all patiens were grouped into A,B,C groups randomly,33cases inA group,31 cases in B group and 34 cases in C group.2,Equipment for studyAquilion 64 CT of tosiba,diagnosis center of medical imaging department3,Examination methodPatients in exposure suit were scanned routinely first(120kv,60mAs).and then added a low dosage scanning of same the range as just now(2cm),which was admited by patients himself.4,Evaluated imageImages of ABC groups were transmitted to PACS center.Two experts evaluated images and scored for image quality for 2,1,0.nosie evaluation:compared standerd deviation of ROI(region of interest) CT values.We took routine scanning procedure as gold standerd to evaluate diagnosis value of low x-ray dosage scanning technology, sensitivity and specificity were calculated as index.Radialization dosage were evaluated by CTDI.5,Statistic analysisSPSS13.0 was used to analysize data of each group.Kruskal-Wallis H test were done.When p＜0.05,It makes sense. Experiment findings1,Image quality scores of low x-ray scanning groups and statistical resultsThere were no statistical differences between orbital bones,muscles and optical nerve in low x-ray scanning groups.There were statistical differences between lacrimal glands,fat in orbital cavity,lens,vitreous body,ring of eyeball.2,Image quality scores of routine scanning groups and low x-ray scanning groups and statistical resultsNosies between groups were proved to have statistical differences,low x-ray scanning groups had higher nosies.what is more,the lower the x-ray dosage was,the higher the nosies were.3,Authenticity evaluation of low x-ray scanning technology routine scanning groups were set to be gold standerd.Both sensitivity and specificity were 100%in low x-ray scanning groups,and the diagnosis value did not declined when compared with routine scanning groups.4,Comparsion of radialization dosage between groupsCTDI of D group(routine scanning group) was 19.2mGy.low x-ray scanning groups included ABC groups.CTDI of A group was 3.2mGy,16.7%of routine scanning group.CTDI of B group was 4.8mGy,25%of routine scanning group.CTDI of C group(120kv,40ma) was 6.4mGy,33.3%of routine scanning group.Compared with routine scanning group,radialization dosage declined obviously in low x-ray scanning groups.ConclusionWhen scanned with Protocol A(20mA),images were qualified for orbit bones diagnosis.When scanned with Protocol B(30mA),images were qualified to diagnose orbit bones and soft tissues ouside the eyeball.When scanned with Protocol C(40mA), images were qualified for orbita diseases.