An autoradiographic search for radioactive particles in the lungs of cigarette smokers.

Mucosal samples from the bifuracation of a major bronchus were examined from 23 patients undergoing diagnostic bronchoscopy. Samples were autoradiographed using a technique that avoids any contact between tissue and reagents until the end of autoradiographic exposure. The autoradiographs were scanned for a-particle tracks. No significant level of alpha -activity was detected, even in samples from heavy smokers who had continued to smoke within several hours of the bronchoscopy. The lower limit of detection of a-activity in this experiment was equivalent to about 55.5 becquerrels/kg (1,500 pCi/kg) Polonium-210. These results do not support the hypothesis presented by others that a radioactivity in particulate material of cigarette smoke contributes significantly to the association between cigarette-smoking and bronchial carcinoma.