SENSITIVITY IN ELECTRON MICROSCOPE AUTORADIOGRAPHY FOR 125I

Abstract

Sensitivity in electron microscope autoradiography was determined for 125I. Values are given using Ilford L4 and Kodak NTE emulsions combined with different developers. The extent of self-absorption as a function of section thickness and heavy metal staining and the effect of radiation dose (dose dependence) were assessed. It was found that the over-all efficiency for 125I was better than that for tritium and that, as is the case with tritium, there is a distinct "dose dependence" especially when Microdol X is the developer. Self-absorption studies indicate that self-absorption is increased by about 15% when the specimen thickness is increased from 300 to 1000 Å. An increase of under 15% is also introduced by heavy metal staining of sections in this thickness range.