Alpert N M, Barker W C, Gelman A, Weise S, Senda M, Correia J A
Department of Radiology, Massachusetts General Hospital, Boston 02114.
J Cereb Blood Flow Metab. 1991 Mar;11(2):A26-30. doi: 10.1038/jcbfm.1991.33.
The limits of quantitation with positron emission tomography (PET) are examined with respect to the noise propagation resulting from radioactive decay and other sources of random error. Theoretical methods for evaluating the statistical error have been devised but seldom applied to experimental data obtained on human subjects. This paper extends the analysis in several ways: (1) A Monte Carlo method is described for tracking the propagation of statistical error through the analysis of in vivo measurements; (2) Experimental data, obtained in phantoms, validating the Monte Carlo method and other methods are presented; (3) A difference in activation paradigm, performed on regional CBF (rCBF) data from five human subjects, was analyzed on 1.6-cm diameter regions of interest to determine the mean fractional statistical error in PET tissue concentration and in rCBF before and after stereotactic transformation; and (4) A linear statistical model and calculations of the various statistical errors were used to estimate the magnitude of the subject-specific fluctuations under various conditions. In this specific example, the root mean squared (RMS) noise in flow measurements was about three times higher than the RMS noise in the concentration measurements. In addition, the total random error was almost equally partitioned between statistical error and random fluctuations due to all other sources.
结合正电子发射断层扫描（PET）放射性衰变及其他随机误差源产生的噪声传播情况，对PET的定量限进行了研究。已设计出评估统计误差的理论方法，但很少应用于在人体受试者上获得的实验数据。本文从几个方面扩展了分析：（1）描述了一种蒙特卡罗方法，用于通过体内测量分析追踪统计误差的传播；（2）给出了在体模中获得的验证蒙特卡罗方法及其他方法的实验数据；（3）对来自五名人类受试者的局部脑血流量（rCBF）数据采用不同的激活范式，在直径1.6厘米的感兴趣区域进行分析，以确定立体定向变换前后PET组织浓度和rCBF中的平均分数统计误差；（4）使用线性统计模型和各种统计误差的计算来估计不同条件下受试者特异性波动的大小。在这个具体例子中，血流测量中的均方根（RMS）噪声比浓度测量中的RMS噪声高约三倍。此外，总随机误差几乎平均分配在统计误差和所有其他来源引起的随机波动之间。
