DR摄片管电压与影像质量和辐射剂量的相关性研究

Effects of kV on Image Quality and Radiation Dose for Digital Radiography

目的:研究数字X线摄影设备管电压与影像质量和辐射剂量的相关性。方法:确认数字X线摄影设备处于良好状态,用CDRAD2.0体模,测试管电压对影像质量及剂量学参数的影响。结果:影像质量存在随管电压的增加而降低的趋势,在70 kV和90 kV时影像质量最好,IQFinv分别为6.27和6.10,而在110 kV时影像质量最差,IQFinv为4.27。从60 kV到80 kV,图像的像素值下降13%;而80 kV到130 kV,图像的像素值在很小范围内波动,变化率仅在2%左右。随着管电压值的增加,图像噪声呈逐渐增高趋势,与60 kV相比,90、120 kV的噪声值分别上升了9.6%和16.9%。IQFinv与剂量和面积之积之间呈正相关(P<0.05)。结论:对于数字化X线摄影设备,以合适的管电压和曝光量为曝光参数可以获得较好的图像质量,并有效控制受检者剂量。

Objective To study the correlation of kV with image quality and radiation dose for digital radiology（DR）. Methods Quality assurance（QA） was performed with BARRACUDA system to make sure DR x-ray machine was in good condition. On condition that CDRAD 2.0 phantom was used, radiation dose and image quality parameters were recorded while changing kV.Results Image quality （IQ） was decreased with increasing tube voltage. IQ reached best at tube voltage of 70 kV and 90 kV with IQFinv 6.27 and 6.10, while least at 110 kV with IQFinv 4.27. Value of pixels were decreased by 13% when tube voltage was increased from 60 kV to 80 kV, but only changed by 2% when tube voltage was increased from 80 kV to 130 kV. Pattern noise was increased with tube voltage. Compared with that of 60 kV, pattern noise was respectively increased by 9.6% and 16.9% at 90 kV and 120 kV. Significant positive correlation was observed between IQFinv and DAP（P〈0.05）. Conclusion High image quality and effective control of radiation dose in examinees can obtain proper tube voltage and mAs in DR.