CT值线性的检测与分析

Measurement and Analysis of CT Number Linearity

目的通过测量CT值,探讨CT设备CT值线性的评价方法。方法用Catphan500体模的CTP401模块,测量四种目标物质的CT值,计算CT值线性、对比度标度和不确定度。结果不同重建算法CT值的差异有统计学意义(P<0.001),sharp和smooth重建算法的对比度标度分别为1.90×10-4cm-1.Hu-1和1.79×10-4cm-1.Hu-1。结论CT值线性良好是CT设备影像质量控制重要的一环,在CT值线性测试报告中应载明使用的重建算法和不确定度。

Objective To explore the evaluation method for CT number linearity by measuring CT numbers. Methods The model CTP401 of Catphan500 phanton was adopted to measure CT numbers of four objective substances,then CT number Linearity,eontrast scales, and uncertainties were calculated. Results Statistically significant differences in CT numbers were found between the two reeonstruetion algorithms（P〈0.001） , The contrast scale of sharp reconstruction algorithm was 1.90×10^-4cm^-1·Hu^-1 and smooth reconstruction algorithm was 1.79×10^-4cm^-1·Hu^-1. Conclusions Qualified CT number linearity is important to image quality control in CT scanners, Reconstruction algorithms and uncertainties must be marked in test reports of CT number linearity.