Salpeter M M, McHenry F A, Salpeter E E
J Cell Biol. 1978 Jan;76(1):127-45. doi: 10.1083/jcb.76.1.127.
The previous publications of this series described the expected grain distributions around model radioactive structures in EM autoradiographs as a function of the specimen resolution. This family of expected distributions was called the "universal curves". In the present study, experiments on 14C-sources were compared, significant differences were found depending on the energy of the isotope. These differences were primarily in the tails of the distributions, and are therefore important in correcting for cross-scatter when analyzing electron microscope autoradiographs. Using the universal curves unique for 125I, 3H, and 14C, we designed three sets of transparent overlays, or "masks", one set for each of these isotopes. The masks can be used by an investigator in a manner similar to that suggested by Blackett and Parry to generate grain distributions in autoradiographs on the basis of any desired hypothesis regarding the levels of radioactivity in different structures. A subsequent comparison between these generated distributions and those obtained from the observed grains in these autoradiographs leads to a determination of the most likely levels of radioactivity in the tissue. A computer (described in an Appendix by Land and Salpeter) can be used to find the "best fit" levels of radioactivity in complex cases. The accuracy of the masks was checked on generated line sources for each of the three isotopes.
本系列之前的出版物描述了在电子显微镜放射自显影片中，围绕模型放射性结构的预期颗粒分布与标本分辨率的函数关系。这一系列预期分布被称为“通用曲线”。在本研究中，对¹⁴C源的实验进行了比较，发现根据同位素的能量存在显著差异。这些差异主要在分布的尾部，因此在分析电子显微镜放射自显影片时对交叉散射进行校正时很重要。利用针对¹²⁵I、³H和¹⁴C的独特通用曲线，我们设计了三组透明覆盖物，即“掩膜”，每种同位素一组。研究人员可以按照布莱克特和帕里建议的方式使用这些掩膜，根据关于不同结构中放射性水平的任何所需假设，在放射自显影片中生成颗粒分布。将这些生成的分布与从这些放射自显影片中观察到的颗粒所获得的分布进行后续比较，从而确定组织中最可能的放射性水平。在复杂情况下，可以使用计算机（兰德和萨尔彼得在附录中进行了描述）来找到放射性的“最佳拟合”水平。针对三种同位素中的每一种，在生成的线源上检查了掩膜的准确性。
