Abstract: There are described heat-developable photosensitive image-recording elements which have an alkali-generating system incorporated therein. In the alkali-generating system, a slightly water-soluble metal compound is reacted with a salt of 2-hydroxy-pyridine-N-oxide, or its derivatives, in the presence of a fluid such as water, to form an insoluble precipitate and the alkali required for silver image development during processing. The image-recording materials are useful as image-forming materials in thermographic and photothermographic processes.

Abstract: Disclosed are cationic complexes of Tc-99m and ligands having the structure: ##STR1## wherein: R.sup.1 is hydrogen or is selected from the group consisting of C.sub.1 to C.sub.20 alkyl; C.sub.3 to C.sub.12 cycloalkyl; C.sub.7 to C.sub.24 aralkyl; C.sub.2 to C.sub.16 alkyl ethers, thioethers, ketones or esters; C.sub.7 to C.sub.27 aralkyl ethers;R.sup.2 is hydrogen or is a C.sub.1 to C.sub.4 lower alkyl radical selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl and tert-butyl.