【摘要】 目的 評價64層螺旋CT低劑量冠狀動脈血管成像的價值。 方法 2009年1-6月157例患者隨機分為3組，常規劑量組（A組）管電流量采用1 000 mAs，兩個低劑量組（B、C組）分別采用800、600 mAs。對3組的圖像質量、噪聲、CT劑量指數（CTDI）、劑量長度乘積（DLP）和有效劑量（ED）進行評估。 結果 A、B、C組圖像噪聲分別為20.50±3.23、23.02±3.05和26.28±2.58，組間差異均無統計學意義（Pgt;0.05）；A、B、C組的CTDI分別為（58.7±0.23）、（46.98±2.27）、（35.28±3.56） mGy，DLP分別為（1 050.88±89.63）、（846.21±57.86）、（641.13±32.15） mGy?cm，ED分別為（14.78±2.56）、（11.85±1.87）、（8.98±1.15） mSv，B、C組的CTDI、DLP、ED均明顯低于常規劑量A組（Plt;0.05），C組的CTDI、DLP、ED均為3組中最低值。 結論 64層螺旋CT冠狀動脈血管檢查，采用600 mAs管電流量獲得的冠脈圖像既可滿足診斷需要，又可使患者接受的輻射劑量降低。【Abstract】 Objective To evaluate the best tube current for low-dose radiation CT in coronary artery imaging by 64-slices multi-detector CT. Methods From January to June 2009, a total of 157 consecutive patients were randomly divided into 3 groups: group A (conventional group): 1 000 mAs; group B: 800 mAs; group C: 600 mAs. The image quality, noise, CT dose index (CTDI), dose length product (DLP) and effective dose (ED) in each group were measured and compared respectively. Results The image noise scores in group A, B, and C were (20.50±3.23), (23.02±3.05) and (26.28±2.58), respectively. There was no statistically significant difference among the three groups in the two indexes (Pgt;0.05). The CTDI in group A, B and C were (58.7±0.23), (46.98±2.27), and (35.28±3.56) mGy, respectively; the DLP in each were (1 050.88±89.63), (846.21±57.86), and (641.13±32.15) mGy?cm, respectively; the Ed were (14.78±2.56), (11.85±1.87), and (8.98±1.15) mSv, respectively. All of the differences among the three groups in CTDI, DLP and ED were statistically significant (Plt;0.05). Conclusion The image with 600 mAs as tube current in the coronary artery imaging of 64-slices multi-detector CT could fulfill the need of the diagnosis, and the radiation dose is apparently lower than the conventional scan.
【摘要】 目的 探討多層螺旋CT低劑量掃描在小兒上尿路梗阻性疾病中的應用價值。 方法 2008年1月-2009年6月經臨床手術證實尿路梗阻的患兒52例，按梗阻的原因分為結石組13例與非結石組39例。將非結石組患兒，按照年齡分為0~1歲（8例）、1~5歲（16例）和5~10歲（15例）3個組，均采用個性化的低劑量掃描方式。 結果 結石組與非結石組陽性診斷率均為100%。低劑量掃描患兒所接受的輻射劑量明顯降低，CT掃描管電流不變，管電壓降低1/3，CT檢查的輻射劑量可降低約70%，且均可達到臨床診斷要求。 結論 多層螺旋CT低劑量個性化掃描在小兒上尿路梗阻性疾病中診斷中具有明顯優勢。【Abstract】 Objective To evaluate low-dose multislice spiral CT for upper urinary tract obstruction in children. Methods From January 2008 to June 2009, 52 children with upper urinary tract obstruction were diagnosed via clinical surgeries. The patients were divided into two groups according to whether having renal calculus (13 patients) or not (39 patients). The patients in non-calculus group were divided into three sub-groups: aged 0-1 (eight patients), 1-5 (16 patients), and 5-10 (15 patients). Low dose multislice spiral CT with different doses was performed. Results The rate of positive predictive diagnosis was 100% in both calculus and non-calculus group. Low dose scan reduced the radiation dose of children. The fixed tube current and the decreased tube voltage (decreased 1/3) led to the decrease of the radiation dose (decreased 70%), which were feasible for diagnosis. Conclusion Low-dose multislice spiral CT was available for upper urinary tract obstruction in children.
