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Objective To evaluate the feasibility of low-tube-voltage, low injection rate, low contrast agent dosage in combination with iterative model reconstruction ( IMR) algorithm in CT angiography ( CTA) of the head-and-neck vessels .Methods Sixty patients who underwent CT angiography of the head-and-neck vessels were randomly divided into groups A and B with 30 cases in each group .Patients in group A received a conventional scan with 120 kVp and filterback projected ( FBP) reconstruction .Patients in group B received a low-dose scan with 80 kVp, and image reconstruction with FBP ( group B1) and IMR (group B2)algorithm.The contrast agent protocol were as follows: the injection time in all patients was 10s, the injection rate was 4.5-5.5 ml/s in group A while 3.5-4.0 ml/s in group B.The CT values of artery, image noise, signal to noise ratio ( SNR) and contrast to noise ratio ( CNR) were measured and compared among three groups with One-way ANOVA analysis . Image quality was evaluated by two radiologists with five scale method , and compared with Kruskal-Wallis test .The CT dose index volume (CTDIvol) and dose length product ( DLP) were recorded and compared between groups with two independent samples t-test.Results The image quality scores of groups A , B1and B2 were 3-5, 2-4 and 3 -5, respectively .Image quality of twelve patients in group B 1 couldn′t meet the diagnostic requirements but none in group A and B 2.The objective image parameters SNR and CNR for group B 2 were equal to group A ( P >0.05), while those for group B1 were lower than group A (t=13.39, 9.45, P<0.05) and group B2 (t=-12.14, -9.96,P<0.05).CTDIvol and DLP for group B were separately 80.9%, 81.3%lower than those of group A(t=39.1, 32.2,P<0.05).The injection rate and contrast agent volume for group B were separately 22.0%, 22.1% lower than those of group A ( t=20.8, 20.8, P<0.01) .Conclusions It is feasible in CT angiography of the head-and-neck vessels with lower tube-voltage, lower injection rate, lower contrast agent dose and combining with iterative model reconstruction algorithm.This protocol can reduce the radiation dose by 81.3% while maintaining image quality .Trial registration Chinese clinical trial registry ,ChiCTR-BOC-16010060.
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Objective To investigate the feasibility of setting mAs in liver enhanced CT scan according to plain scan noise with fixed mA CT scanner,in order to reduce the radiation dose.Methods One hundred continuous patients underwent liver enhanced CT scan (group A) prospectively.Two hundred and fifty mAs was used in plain and enhanced CT scans.Noises of plain and venous phase CT images were measured,and the image quality was evaluated.The equation between mAs of enhanced scan and noise of plain scan image was derived.Another 100 continuous patients underwent liver enhanced CT scan (group B).Enhanced scan mAs was calculated from noise on plain scan by using the equation above.Noises on venous phase images were measured and the image quality was measured.Based on body mass index (BMI),patients in groups A and B were divided into three subgroups respectively:BMI ＜ 18.5 kg/m2,18.5 kg/m2 ≤ BMI ＜ 25.0 kg/m2 and BMI ≥ 25.0 kg/m2.Image quality score was compared with nonparametric rank sum test,CT dose index (CTDI) and effective dose (ED) were measured and compared between each subgroup with 2 independent samples t or t' test.Results The equation between enhanced scan mAs (mAsX) and plain scan noise (SDp) was as follows:mAsX =mAs1 × [(0.989 × SDp + 1.06) /SDx]2,mAs1 =250 mAs,SDx =13.In patients with BMI ＜ 18.5 kg/m2,ED of group A [(6.86 ±0.38) mSv,n =12] was significantly higher than group B [(2.66 ±0.46) mSv,n =10)] (t =18.52,P ＜0.01).In patients with 18.5 kg/m2 ≤ BMI ＜ 25.0 kg/m2,ED of group A [(7.08 ± 0.91) mSy,n =66] was significantly higher than group B [(4.50 ± 1.41) mSv,n =73] (t' =10.57,P ＜ 0.01).In patients with BMI ≥25.0 kg/m2,there was no significant difference between EDs of group A (7.54 ± 0.62 mSv,n =22) and group B [(8.19 ±3.16) mSv,n =17] (t' =0.89,P =0.39).Image quality of 5 patients in group A and none in group B did not meet the diagnostic requirement.Conclusion Setting mAs of enhanced scan according to plain scan noise could reduce the radiation dose with maintainence of image quality.
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Objective To examine supine fulcrum pressurized radiograph to predict spinal flexibility in adolescent idiopathic scoliosis (AIS). Methods 1. Empirical study: put two points (A and B) on one side of the plastic stick and one point on the other side ( C), pressurize on the plastic stick when point C is in the middle of A and B, and then measure the projection shifting of point A. Repeat the pressure test when the distance between A and C doubled. Analyze the effect of increasing distance on diminishing pressure. 2.Clinical study :45 patients ( 16 males and 29 females) underwent standing anteroposterior radiograph ,fulcrum lateral flexion radiograph, supine lateral flexion radiograph. The Cobb's angles were measured and the flexibility ratio was determined on preoperative fulcrum radiograph. Results (1) If the length of A and C was 25 cm, pressurize on point C, when pressure quantitative scale number located 1 scale and 2 scale of the rule, projection shifting of point A were 5 cm and 10 cm. If the length of A and C was 50 cm, pressurize on point C, when pressure quantitative scale number located 1 scale and 2 scale of the rule, projection shifting of point A were 8 cm and 15 cm. The longer the distance, the lesser the pressure force of plastics stick. (2)The Cobb angles and curve flexibility provided by fulcrum lateral flexion radiograph had significant difference from that provided by supine lateral flexion radiograph in male group and female group. Cobb angles of male group was 28. 6°± 4. 1 °, 16. 7°± 4. 6° respectively (t= 7. 438, P ＜ 0. 01 )and curve flexibility was 47. 6% ±8. 1% ,69. 4% ± 8. 5% respectively( t = 7. 438, P ＜ 0. 01 ). Cobb angles of female group was 24.5°± 2. 7°,12. 6°±2. 4° respectively(t = 17. 540,P ＜0. 01 )and curve flexibility was 53.4% ±5.2% ,76. 0% ±4. 7% respectively(t = 17. 54, P ＜ 0. 01 ). The flexibility of spinal main curve of female patients was obviously higher than male patients. Conclusions Supine fulcrum pressurized technique can make up for the insufficiency of supine lateral flexion technique, and provide a convenient, safe, precise and useful method for evaluation of spinal flexibility in AIS.
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Objective To search a kind ofphotograph system which can be confirmed immediately to photograph a picture after expose and never needed to carry on a dark box again to replace or the IP plank read. Methods Pass to usher in a DaoJin company numeral to turn to move the type X line to photograph system to carry out. Results The DR bedside photographs to photograph with CR bedside to compare, saved time, raised picture resolution and quality, lowered a sufferer to hurt and saved a luck camp cost. Conclusion Carried out to photograph a picture after expose can immediately get confirmation, have never need is carry on a dark box to replace or the IP plank read.
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Objective To evaluate the clinical value of the application of MUSICA in the post processing on the full spine radiography.Methods The film were exposed one time of total spine of patients by using the special cassette(2～3 IP plates).The information of IP plates were gathered to the image post processing workstation one by one separately.The selected images were pieced together to form a complete total spine photography by using the special software in the computer.Results The quality of 2500 images were obviously improved.Conclusion The application of MUSICA not only improves the precision of measuring COBB angle,but also supplies more information for making operation plan and evaluating curative effect after operation.
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Objective To investigate the application of slide pat and the prevention of secondary lesion when carrying injured patients.Methods 1 050 surgical cases were summarized retrospectively who undergoing X-ray examination with skull/vertebral/ lower limbs injured.The patient was moved on a special slide pat between bed and examining table with no change in body-position and the nursing staffs can keep the fracture stable with delicate and coordinated technique.Results No abnormal signs occurred when patients were carried on the special slide pat.Conclusion It is time-saving and labor-saving to move patients using slide pat.Because the changing times of body position are greatly reduced,so the patients are relieved and severe complication was prevented.[Chinese Medical Equipment Journal,2008,29(2):86-87]
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This paper analyzes the routine failures and operating flow of full-functional DR-EIDOS3000 and points out the design deficiencies of the detector stand,the elevating table and the console.At last,some countermeasures are suggested for the hidden trouble.