Instrumentation factors affecting variance and bias of quantifying tracer uptake with PET/CT
Instrumentation factors affecting variance and bias of quantifying tracer uptake with PET/CT
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DOI：
10.1118/1.3499298
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发表时间：
2010-11-01
期刊：
影响因子：
3.8
通讯作者：
Kinahan, P. E.
中科院分区：
文献类型：
--
作者：
Doot, R. K.;Scheuermann, J. S.;Kinahan, P. E.
目的：需要从仪器因素中量化PET示踪剂摄取的固有方差和偏倚，以确定任何测量差异的显著性，例如量化对治疗的反应。作者在一台扫描仪和三个PET中心使用长半衰期体模的单一协议研究了作为对象大小、采集、重建和分析方法的函数的系列PET活性测量的可重复性和再现性。方法：作者评估了在均匀体模和NEMA NU-2图像质量（IQ）体模，在环氧树脂基质中填充9个月半衰期Ge-68。通过除以共同衰变校正的真值将活性测量值归一化，并报告为回收系数（RC）。每个实验集由20次连续PET扫描组成，扫描对象为固定体模以评估可重复性，扫描对象为重新定位的体模以评估可重复性。一个研究中心进行了一系列全面的重复性和再现性实验，而另外两个研究中心使用相同的IQ体模重复了再现性实验。一个方程推导出一个新的PET测量从一个已知的SD的基础上的两个PET measures.Results之间的可用的重合计数的比率估计SD：对于固定的均匀体模扫描，SD的最大RC的三至五倍小于预测的不相关的像素内的圆形区域的兴趣（ROI），直径范围从1到15厘米。对于1 cm直径ROI的固定IQ体模扫描，平均和最大RC的平均SD范围为1.4%至8.0%，取决于采集和重建方法（变异系数范围为2.5%至9.8%）。对于分析和迭代重建方法，观察到相似的SD（p >= 0.08）。2D采集的RC SD显著高于3D采集（p
Purpose: The variances and biases inherent in quantifying PET tracer uptake from instrumentation factors are needed to ascertain the significance of any measured differences such as in quantifying response to therapy. The authors studied the repeatability and reproducibility of serial PET measures of activity as a function of object size, acquisition, reconstruction, and analysis method on one scanner and at three PET centers using a single protocol with long half-life phantoms.Methods: The authors assessed standard deviations (SDs) and mean biases of consecutive measures of PET activity concentrations in a uniform phantom and a NEMA NU-2 image quality (IQ) phantom filled with 9 months half-life Ge-68 in an epoxy matrix. Activity measurements were normalized by dividing by a common decay corrected true value and reported as recovery coefficients (RCs). Each experimental set consisted of 20 consecutive PET scans of either a stationary phantom to evaluate repeatability or a repositioned phantom to assess reproducibility. One site conducted a comprehensive series of repeatability and reproducibility experiments, while two other sites repeated the reproducibility experiments using the same IQ phantom. An equation was derived to estimate the SD of a new PET measure from a known SD based on the ratios of available coincident counts between the two PET measures.Results: For stationary uniform phantom scans, the SDs of maximum RCs were three to five times less than predicted for uncorrelated pixels within circular regions of interest (ROIs) with diameters ranging from 1 to 15 cm. For stationary IQ phantom scans from 1 cm diameter ROIs, the average SDs of mean and maximum RCs ranged from 1.4% to 8.0%, depending on the methods of acquisition and reconstruction (coefficients of variation range 2.5% to 9.8%). Similar SDs were observed for both analytic and iterative reconstruction methods (p >= 0.08). SDs of RCs for 2D acquisitions were significantly higher than for 3D acquisitions (p