数字乳腺X线摄影系统成像参数优化研究

摘要

目的：本文对数字乳腺X线摄影系统中成像参数的最优化进行初步研究。方法采用4 cm厚的PMMA乳腺模体，选择不同的靶/滤过组合、管电压和管电流时间乘积，进行手动成像。利用ImageJ软件中的qa-distri插件得到图像信号区域和背景区域的像素均值和标准差，以此计算图像的对比度噪声比。然后根据对比度噪声比和平均腺体剂量两个参数，评估靶/滤过组合、管电压和管电流时间乘积对成像的影响。结果对于厚度为4 cm的乳房，使用钼/铑组合，在得到同等质量图像的情况下，受检者吸收的平均腺体剂量比使用钼/钼组合低。结论，在数字乳腺X线摄影系统临床使用过程中，要选择适宜的曝光参数，既能保证图像质量，又能降低受检者的辐射风险。%Objective Optimizing imaging parameters in digital mammography system was preliminarily investigated in this paper.Methods The 4-cm-thick PMMA (Poly-Methyl-Meth-Acrylate) breast simulating phantom was used, and two different combinations of anode/iflter material and a wide range of peak tube voltage and tube current-time product were employed for manually imaging. The images were analyzed by using a set of plug-in applications in the ImageJ software for acquisition of the pixel mean value and standard deviation measurements so as to calculate contrast noise ratio. Then, the impact of combination of anode/iflter material, peak tube voltage and tube current-time product on images was assessed by using contrast noise ration and mean glandular dose.Results For the 4-cm-thick breast, the same image quality could be achieved with a lower dose by using the combination of Mo/Rh anode/ifler than the combination of Mo/Mo.Conclusion Therefore, imaging parameters should be optimized in using of the digital mammography system to assure image quality and keep glandular dose lower.