利用点源体模测量螺旋CT层厚灵敏度分布曲线的方法

Determination of spiral CT slice sensitivity profile using a point response phantom

螺旋CT是新近推出的一种新型医用诊断设备 ,它比传统的轴向CT的功能更强 ,速度更快 ,对临床诊断具有独特的重要作用。螺旋CT的基本性能参数与轴向CT的性能参数基本相同 ,如高对比分辨率、低对比分辨率、断层厚度、CT值线性等 ,有些参数 (如高低对比分辨率、CT值线性 )可以采用与普通CT相同的方法进行测试。对于螺旋CT层厚的测量 ,普遍采用断层灵敏度分布曲线 (SliceSensitivityProfileSSP)来反映其层厚的大小 ,而不能使用与轴向CT层厚测量相同的方法 ,因为其CT图像受到与其相邻的层面的影响。这种影响依赖于螺距的大小以及螺旋插补算法的选择。因此 。

Spiral CT is a new type of medical equipments that has more powerful functions and faster speed than that of conventional CT. The basic performance parameters of spiral CT are almost the same as that of axial CT and can be measured by using the same methods. But the slice thickness measurement and the slice sensitivity profile (SSP) are taken the methods rather than that of in axial CT. Therefore it is necessary to find out a special test phantom and methods for adapting the characteristics of spiral CT. In this paper, a point response phantom is used to evaluate the spiral CT SSP and a method is presented to measure its parameters.