低剂量胸部CT自动管电流调节技术在超重体型患者检查中的可行性研究

目的：探讨16层螺旋CT自动管电流调节技术（CAREDose4D）在超重体型患者检查中的可行性。方法：收集行胸部CT检查的超重体型患者（BMI值于24-27．9之间）100例，扫描分低剂量组（A组）和常规剂量组（B组），其中A组扫描运用CAREDose4D技术自动调节管电流；B组扫描运用常规剂量管电流为70mAs扫描。扫描完成后记录加权CT剂量指数（CTDlvol）、有效mAs值、剂量长度乘积（DLP），计算出有效剂量（ED）及剂量减低比值（DR），并比较两组的剂量及图像质量。结果：与B组相比，A组常规扫描辐射剂量显著降低，差异有显著统计学意义（P〈0．01），A组剂量减低比值（DR）降低约20．84％，而图像质量无明显下降，不影响诊断，在主动脉弓上4cm（肺尖）层面A组图像质量优于B组，差异有统计学意义（x^2=8．442，P=0．015）。结论：自动管电流调节技术既可以减少患者的辐射剂量，对待超重体型患者个体化、人性化，又不影响影像诊断，是一项有价值的检查方法。

Feasibility Study on the Low-dose Chest CT Use of Automatic Tube Current Modulation in Overweight Patients

Objeotive： To study the feasibility of 16 slice spiral CT use automatic tube current modulation （CARE Dose 4D） in overweight patients. Methods： 100 overweight patients （The value of body mass index in the 24 - 27.9）. were collected and randomly divided into low-dose group （group A） and routine group （group B）, group A was treated by CARE Dose 4D to scan. Group B was scanned with tube current of 70 mAs. After scanning, the volume CT dose index （CTDIvol）, effective mAs, dose length product（DLP） were recorded. The effective dose （ED） and the dose reduction （DR） were calculated. Furthermore, the radiation dose and image quality were compared between two groups. Results： Compared with group B, the effective dose significantly reduced in group A （P〈0.01）, the dose reduction （DR） reduced about 20.48%, while obvious difference could not be found in the quality of images obtained from group A and group B. At the apex of the lung level, the image quality of group A was superior to group B （X2 =8.442,P=0.015）. Conclusion： Automatic tube current modulation may not only reduce the radiation dose and make overweight patients＇ examination more individualized and humanity, but also not affect the diagnosis results. It was a valuable diagnostic method.