重建参数对于基于CZT半导体探测器SPECT/CT系统锝绝对定量准确性的影响  

Impacts of Reconstruction Parameters on the Accuracy of Absolute Technetium Quantification of the Cadmium-Zinc-Telluride-Based SPECT/CT System

作　　者：王深[1] 张如意 王澎[1] 谭建[1] 李宁[1] 林晓云[1] 孟召伟[1] 贾强[1] WANG Shen;ZHANG Ruyi;WANG Peng;TAN Jian;LI Ning;LIN Xiaoyun;MENG Zhaowei;JIA Qiang(Department of Nuclear Medicine,Tianjin Medical University General Hospital,Tianjin 300052,China)

机构地区：[1]天津医科大学总医院核医学科,天津300052

出　　处：《中国医疗设备》2022年第10期51-55,64,共6页China Medical Devices

摘　　要：目的基于数字化碲-锌-镉(Cadmium-Zinc-Telluride,CZT)半导体探测器的单光子发射计算机断层扫描(Single Photon Emission Computed Tomography,SPECT)/CT系统具有良好的空间分辨率和能量分辨率等优点,但不同的重建参数对CZT SPECT/CT定量的影响还需要进一步验证,本研究旨在评估重建参数(迭代次数、迭代子集、后滤波和图像校正方法)对CZT SPECT/CT锝定量准确性的影响。方法采用锝液将体模填充为32∶1靶本(Target to Background,T/B)比。测量平均摄取值,以评估不同采集和重建参数下的恢复系数(Recovery Coefficients,RCs)的变化。图像质量采用美国电气制造商协会NU 2-2012标准进行评估。结果迭代次数与RCs之间存在显著的相关性(1~35次,r=0.58~0.92;35~90次,r=0.97~0.99),高斯滤波器的半高宽值与RCs之间也存在显著相关性(r=-0.87~-1.00,P<0.05)。回归分析中,1~35次迭代的β值高于35~90次迭代的β值(0.63~1.60 vs.0.02~0.15)。在所有T/B比值中,衰减校正(Attenuation Correction,AC)+散射校正(Scatter Correction,SC)+分辨率恢复校正(Resolution Recovery Correction,RR)组合计算的RCs精度更高(67.80%~106.70%)(P<0.001)。同时,AC+SC+RR组合的图像视觉质量和对比度最好(AC+SC+RR vs.AC+RR;AC+SC+RR vs.AC+SC,P<0.0.001)。结论迭代次数对于绝对定量有很大的影响,较小的病灶需要更大的迭代次数来提高定量准确性,其影响主要集中在35次迭代范围内;子集数对于绝对定量的影响较小,RCs在20个子集后已无明显变化;高斯滤波器的FWHM值对于绝对定量的影响最大,RCs随着FWHM值的增加而显著降低且无平台期可供选择。图像校正方法对于绝对定量也有较大的影响。其中,AC+SC+RR组合下的绝对定量更接近于真实值且图像质量相对较好。CZTSPECT/CT显示了良好的定量准确度,且35次迭代、20个子集、AC+SC+RR校正组合和不进行滤波是较好的重建参数。Objective The digital cadmium-zinc-telluride(CZT)-based single photon emission CT/CT system has advantages such as good spatial and energy resolution.However,the impacts of different reconstruction parameters on CZT SPECT/CT quantification need to be further verified.This study aimed to evaluate the impacts of reconstruction parameters(iterations,subsets in iterative reconstruction,post-filter,and image correction methods)on the accuracy of technetium quantification of CZT SPECT/CT.Methods A phantom(PET NEMA/IEC image quality)was filled with 32∶1 target-to-background(T/B)ratio of technetium.The mean uptake values(the calculated mean concentrations for spheres)were measured to evaluate the changes of recovery coefficient(RCs)under different reconstruction parameters.The image quality was evaluated using the National Electrical Manufacturers Association(NEMA)NU 2-2012 standard.Results Significant correlations were found between iterations and RCs(r=0.58~0.92 for 1~35 iterations,r=0.97~0.99 for 35~90 iterations),as well as between the full width at half maximum(FWHM)of the Gaussian filter and RCs(r=-0.87 to-1.00,P<0.05).In regression analysis,the regression coefficients of 1~35 iterations were higher than those of 35~90 iterations(0.63~1.60 vs.0.02~0.15).For all T/B ratios,the RCs calculated with attenuation correction(AC)and scatter correction(SC)and resolution recovery correction(RR)combinations were more accurate than those calculated with other combinations(67.80%~106.70%,P<0.05).Meanwhile,the combination of AC+SC+RR had the best visual image quality and percent contrast(AC+SC+RR vs.AC+RR;AC+SC+RR vs.AC+SC,P<0.05).Conclusion The number of iterations has a great impact on the absolute quantification,and smaller lesions need a larger number of iterations to improve the quantification accuracy.Its influence is mainly within the first 35 iterations;the number of subsets has little influence on the absolute quantification and RCs is not change significantly after 20 subsets;the FWHM value of the Gaussian filter has

关 键 词：重建参数 碲-锌-镉 单光子发射计算机断层扫描仪 锝绝对定量 

分 类 号：R817.4[医药卫生—影像医学与核医学]