[Effect of cigarette smoking on diffuse pulmonary uptake of 99mTc-HM PAO]

To investigate the clinical significance of pulmonary uptake of 99mTc-HM PAO, we studied the effect of cigarette smoking on pulmonary uptake of 99mTc-HM PAO. This study included 14 volunteers: 4 nonsmokers and 10 smokers (Brinkmann indexes 544 +/- 270.8). Following injection of 99mTc-HM PAO into the antecubital vein, time-activity curve was obtained with the regional activity of one frame/min. for 30 minutes and 64 x 64 matrices. Characteristics of pulmonary clearance curve, described as C(t) = A exp-kt, and lung/liver uptake ratio (Lu/Li index) at 30 min. after injection were determined, and groups of non-smokers and smokers were compared. In smokers, 99mTc-HM PAO clearance was delayed and k was smaller significantly. Lu/Li index was also higher in smokers. Brinkmann index correlated both with k (r = -0.815, p < 0.01) and Lu/Li index (r = 0.911, p < 0.01). In conclusion, the delayed clearance and retention of 99mTc-HM PAO in the lung may indicate metabolic disorders of the lung due to cigarette smoking.