定位像参数对智能管电压辅助技术联合自动管电流调制技术性能的影响

Influence of Scanning Parameters of the Scout View on the Performance of kV Assist Technology Combined with Automatic Tube Current Modulation Technology

目的探讨定位像的扫描参数对智能管电压辅助(Scout on Tube Voltage Assist,kV assist)技术联合自动管电流调制技术的影响。方法利用GE Revolution CT机和CT剂量体模,改变定位像的管电压、管电流、球管的投射角度以及床相对于机架等中心点的距离,研究使用kV assist技术联合自动管电流调制技术时的断层图像管电流曲线和图像质量。利用ImageJ软件获取断层图像的管电流、容积CT剂量指数和剂量长度乘积,分别计算定位像和断层的信噪比并进行比较。结果当定位像的管电压发生变化时,定位像管电压为120 kV,图像质量较好,且辐射剂量较低。当定位像的管电流发生变化时,但曝光量无明显变化,定位像的管电流对图像质量和辐射剂量基本没有影响。当定位像的投射角度发生变化时,90°和180°结合时图像质量较好,且辐射剂量较低。当CT床相对于机架等中心点的距离发生变化时,扫描部位的中心置于机架机架等中心点时,图像质量较好,且辐射剂量较低。结论通过研究定位像的参数对断层的管电流曲线的影响,发现在使用kV assist技术联合自动管电流调制技术时,选择合适参数可以在获得较好的图像质量,同时能降低CT检查的辐射剂量。

Objective To discuss the influence of scanning parameters of scout on tube voltage assist(kV assist)technology combined with automatic tube current modulation technology.Methods GE Revolution CT and CT dose phantom were used to change the tube voltage,tube current,tube of the scout view,as well as the distance of the bed to the center point of the frame of the scout view.The current curve and image quality of the axial image tube using kV assist technology combined with automatic tube current modulation were studied.The tube current,CTDI_(vol) and DLP of the axial image were obtained by ImageJ software,and the SNR of the scout view and the axial image was calculated respectively for comparison.Results When the tube voltage in scout view was changed,the voltage of scout view tube was 120 kV,the image quality was good,and the radiation dose was low.When the tube current of the scout changed,the exposure did not change significantly,the change of the tube current of the scout view had no effect on the image quality and radiation dose.When the projection angle of the scout changed,the image quality was better when combining 90°and 180°,and the radiation dose was lower.When the distance between the bed and the center point of the frame changed,the image quality was better and the radiation dose was lower when the center of the scanning part was placed at the center point of the frame.Conclusion By studying the influence of scout parameters on tube current curve,the result suggests that when kV assist technology is combined with automatic tube current modulation technology,selecting appropriate parameters can obtain better image quality and effectively reduce exposure.