The construction of 64-slice-dual-source computed tomography(DSCT) is introduced.Its imaging principle and clinical application are put forward.DSCT has special advantages in diagnosing coronary stricture.The principles of DSCT and energy subtraction imaging are expatiated in detail.DSCT has great value in clinical research and application.

Objective To study the effect of image quality and radiation dose by using Z -axis automatic tube current modulation(ATCM),as well as the application of automatic tube current modulation technology.Methods A control group consisting of 25 patients underwent cervical MDCT with fixed-current technique(100-220mA).Of two study groups of 25 patients,one underwent cervical MDCT using z-axis ATCM with the noise index of NI10 and tube current intensity of 80-480 mA,and the other with the noise index of NI12.5 and tube current intensity of 80-369 mA.The noise and mean tube current-time products(mAs) were recorded.Two radiologists evaluated images for diagnostic acceptability.Results All CT examinations of study and control groups were diagnostically acceptable,though objective noise was different with z-axis ATCM than with fixed current.ATCM resulted in significant radiation dose reduction(NI10,94.8?17.9 mAs;NI12.5,74.8? 18.3 mAs),when compared with the fixed current(130.4?43.1 mAs).Conclusion Z-axis Automatic mA technique has no significant change in image quality when compared with the fixed mA technique,but the radiation dose is decreased by 27%(NI10) and 43%(NI12.5),for MDCT evaluation of neck.NI has to be selected on the basis of the tissue,lesion size and nature.

Objective To evaluate the radiation dose and image quality of MinDose techniques in dual-source CT coronary artery angiography.Methods 120 consecutive patients undergoing cardiac CT scans were randomly assigned into 2 groups: Group A1 with the tube current reduced to 20% of the normal tube current outside the pulsing window,and Group A2 with the tube current reduced to 4% of the normal tube current outside the pulsing window (MinDose).The image quality,noise,volume CT dose index (CTDIvol),and effective dose (E) of these two groups were evaluated.Results The mean score of imaging quality of Group A1 was (4.3 ± 0.3 ),not significantly different from that of Group A2 [(4.5 ±0.4),t=0.16,P＞0.05].The value of CTDIvol of Group A1 was (40.2 ±9.6) mGy,significantly higher than that of Group A2 [( 36.4 ± 9.1 ) mGy,t = 3.2,P ＜ 0.05].The E value of Group A1 was (9.1± 2.2) mSv ,significantly higher than that of A2 [( 8.1 ± 1.9) mSv,t = 2.7,P ＜ 0.05].Conclusion Application of the MinDose technique not only reduces the radiation dose to the patient,but also meets the requirement of diagnosis.

Objective To investigate the possibility to create versatile system recovery disc for PACS workstation using the software Ghost 11. Methods Firstly, PACS and Windows software was installed into a PACS workstation. Secondly, S&R&S V9.7 1112F intelligent system -packaging tool and DllCacheManager_V1.6 Dllcache backup -restore tool were used to package the system. Finally, Ghost 11 was adopted to produce mirror image of the system. Results The image could recover system easily. Conclusion The system-recovery disc created by Ghost11 can significantly minimized the workload when the PACS workstation runs into error and improves the maintenance efficiency.

Objective To study how to finish radiography work satisfactorily under emergency situations. Methods Analyses and sum-up were performed from three aspects, including X -ray diagnostic vehicle, radiography and PTSD. Results The vehicle-mounted X-ray machine was kept good state during high strength utilization. 620 cases from the disaster area were examined and the diagnosing quality was better than usual. Conclusion Such aspects are very important for emergency application of vehicle-mounted X-ray machine as the daily maintenance of the machine, high technical level and proper mental intervention.

Objective With the increasing of the CT examination, the dose of x-ray has been brought to public attention. For the sake of making the MDCT technology better applied, available optimal technology has to be used to reduce the x-ray dose to the patients. Methods Many optimal technologies were involved in, such as ECG modulation, cardiac bowtie, 3D dose modulation, compact geometry design, electron collector and speed 4D CARE dose. Results The result of the research showed that the dose of scanning x-ray of CT could be decreased sharply by using optimal technologies. The Q2 values was the standard which could well evaluate the quality of the CT′s images and the dose of x-ray. Conclusion The quality of images and the dose of x-ray can′t be separated, which must be quoted together.

Objective To introduce the techniques and clinical application of coronary arterial calcification measurements by using the multi-slice CT (MSCT). Methods The recent literature on the coronary artery calcium scoring with MSCT were reviewed. The data acquisition, image reconstruction, quantification methods in assessment of calcium and usefulness of calcium scoring in coronary artery disease were investigated. Results MSCT with nearly isotropic volumetric imaging data, subsecond rotation and retrospective electrocardiographic gating could provide better input data for quantification of coronary arterial calcium volume. Conclusion MSCT allows more precise and repeated measurement of coronary arterial calcification with low interexamination variability.

Objective To evaluate the clinical application of the auto trigger technique with dual-source CT in cerebral and cervical vessel. Methods 35 patients were randomly divided into three groups, taking triggered threshold as 20HU,50HU and 70HU respectively, CT-values in segments of left middle cerebral artery, superior sagittal sinus, left common carotid artery adjacent to the fourth cervical vertebrate and internal jugular vein by injection at antecubital vein were all measured. Results The discrepancy of peak in artery among groups was not statistically different. It was statistically different in the same segments of vein. Conclusion CTA of cerebral and carotid arteries with the dual-source CT triggered technique can be clearly showed with 20HU as triggered threshold.

Objective To study the clinical applications of SIVP detecting hepatocarcinoma in cirrhosis.Methods 40 cases of cirrhosis combined with hepatocarcinoma diagnosed by operation and pathology were collected.Control group were scaned with conventional technique,experimental group were scaned with SIVP.Results Only 5 cases catched the optimal scan timing in control group,the accuracy of diagnosis in hepatocarcinoma was 70%;All the cases found the optimal scan timing in experimental group,the detectable rate of hepatocarcinoma was 95%.Conclusion SIVP can find out the optimal timing,which greatly improved accuracy of diagnosing hepatocarcinoma in cirrhosis.

Objective To analysis the CT features and differential points of adrenal myelolipoma.Methods The CT and clinical information of 9 adrenal myelolipomas were collected.Results CT diagnosed 8 cases of adrenal myelolipoma except 1 case misdiagnosing as adenoma.All mass measuring 2.8～10.5 cm in diameter with clear edge,low attenuation value of fat and irregular linear shadow of soft tissure might be seen in mass.Conclusion CT is the best examination of diagnosing,which could show the position,component of the mass and organs around it.