A method to label cigarette smoke with 99mTc.

A method is described to label with 99mTc the particulate matter in the smoke from commercially obtained cigarettes. A solution of technetium heptasulfide is applied to the paper wrapper of the tobacco rod and then dried. Smoke from a cigarette treated in this way contains measurable amounts of 99mTc in the particulate phase. In contrast, no measurable radioactivity is found in the non-particulate (gaseous) phase of smoke. This method yields a gamma-emitting cigarette smoke which will permit future observation of particulate intake, deposition and clearance in experimental animals and man.