Roysam B, Maffitt D R, Miller M I, Saffitz J E, Thomas L J
Electrical Computer and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180.
Microsc Res Tech. 1992 Jan 1;20(1):73-86. doi: 10.1002/jemt.1070200108.
The maximum-likelihood (ML) method for the quantitative analysis of electron-microscopic autoradiographs has been shown to be substantially superior to the conventional crossfire (CF) method. It can generate reliable and accurate tracer concentration estimates with far fewer micrographs and produce valid estimates even at counts low enough to preclude the use of the crossfire method while eliminating the need for special ad hoc treatment of narrow membranous structures as well as the secondary verification of the tracer concentration estimates. Despite these significant advantages, the large computational requirements of the ML method has to date hampered its widespread use. In this paper, we present a new line-integration method that allows us to reduce the computational requirements of the ML method to a point where it becomes feasible to implement it on a small computer system of the type typically available to a laboratory user of EM autoradiography. We present the complete line-integration method for the particular case of EM autoradiography with tritium, and show how it can be adapted to other isotopes. We have constructed a software package that implements the complete maximum-likelihood method on the IBM PC class of machines using our line-integration method. Features of this software package which are of particular importance to the research community are device independence, which makes it usable with a large variety of currently available laboratory equipment, and easy portability of the software and data between different computer systems.
用于电子显微镜放射自显影片定量分析的最大似然（ML）法已被证明远优于传统的交叉火力（CF）法。它能用少得多的显微照片生成可靠且准确的示踪剂浓度估计值，即使在计数低到足以排除使用交叉火力法的情况下也能产生有效的估计值，同时无需对狭窄膜结构进行特殊的临时处理以及对示踪剂浓度估计值进行二次验证。尽管有这些显著优势，但ML法对计算能力的高要求迄今为止阻碍了它的广泛应用。在本文中，我们提出了一种新的线积分方法，该方法能将ML法的计算需求降低到在电子显微镜放射自显影实验室用户通常可用的小型计算机系统上得以实现的程度。我们针对氚标记的电子显微镜放射自显影的特定情况给出了完整的线积分方法，并展示了如何将其应用于其他同位素。我们构建了一个软件包，该软件包使用我们的线积分方法在IBM PC类机器上实现完整的最大似然法。该软件包对研究界特别重要的特性包括设备独立性，这使其能与目前各种各样可用的实验室设备兼容，以及软件和数据在不同计算机系统之间易于移植。
