PQ 2000螺旋CT有效层厚影响因素的实验分析

PQ 2000 Spiral CT Full Width at Half Maximum: Experimental Study on Influencing Factors

目的 介绍螺旋CT中影响有效层厚的扫描条件 ,并根据各种扫描条件下获得的有效层厚数据为临床扫描提供适当的扫描条件 ,获得比较好的CT图像。方法 用PQ 2 0 0 0CT中对有效层厚有影响的扫描条件进行组合 ,分别扫描层厚测量水模 ,利用随机提供的有效层厚测量程序计算出有效层厚。结果 影响有效层厚的扫描条件主要有层厚和螺距 ,螺旋插入算法对有效层厚几乎没有影响。在薄层扫描时 ,螺距对有效层厚的影响更大 ,2mm扫描螺距为 2时有效层厚与普通扫描相比将增宽 3 5 % ;4mm扫描螺距为 2时有效层厚与普通扫描相比将增宽 5 0 %。结论 根据诊断的需要 ,在选择不同的层厚进行螺旋扫描时应选择与之相适应的螺距和重建间隔 ,以获得比较好的图像和更好的图像后处理效果。

Purpose According to the FWHM data obtained in many scans using different parameters, to select suitable scan parameters in order to improve image quality. Methods Scanned the Picker phantom slice section with different scan parameters to obtain the images,then calculated the FWHM of each image using slice calculate program. Results The major factors influencing the FWHM were slice thickness and pitch, the spatial interpolators had little influence on FWHM when the thickness was thinner,the pitch had a great influence on FWHM.At 2mm thickness,the FWHM was boarding 35% compared with normal scan;at 4mm thickness,the FWHM was boarding 50% compared with normal scan. Conclusion To select suitable pitch according to the thickness is important to acquire better images and better image processing.