N,N,N'-Trimethyl-N'-(2-Hydroxyl-3-Methyl-5-123I Iodobenzyl)-1,3-Propanediamine.Hcl (123I-HIPDM) has been used for diagnosis of patients with strokes and dementias. Since this radiopharmaceutical is also accumulated in the lung, we routinely performed a lung image or images immediately prior to cerebral planar and SPECT images after a 3-5 mCi 123I-HIPDM injection. During the past 14 months, we obtained 78 (age from 41 to 92 years, average 66.7 +/- 8.9 years; 64 males, 14 females) suspected stroke or dementia patients' lung images. All lung images were correlated to chest X-ray (CXR) or CT and other clinical data. Sixty five of 78 patients had normal lungs showing homogeneous distribution of activity throughout the lungs which correlated well to normal CXR and/or CT studies. Abnormal scintigraphic patterns of the 13 patients included lung defect (5 bronchogenic carcinoma with or without atelectasis) and decreased uptake in apices (8 chronic obstructive pulmonary disease). The findings of pulmonary intrathoracic pathologies on lung images with 123I-HIPDM suggests further evaluation of the agent for detection of localized pulmonary diseases and pulmonary physiological studies relating to amine metabolism.