Tc-99m Erythromycin lactobionate inhalation scintigraphy in parenchymal lung diseases

We have investigated Technetium 99m erythromycin lactobionate (Tc 99m EL) c learance from the lungs after inhalation, in the presence of an alveolitis. Eighteen patients (6 sarcoidosis, 7 idiopathic fibrosis, and 5 miliary tub erculosis) were imaged after the patients inhaled 1,110 MBq of Tc 99m EL. C learance half time for the first 45 min, for 24 h, and retention at 24 h co rrelated with percentage of lymphocytes in bronchoalveolar lavage fluid (BA L) (r =.729, r =.883, and r =.826, respectively). There was a positive corr elation between peripheral penetration (PP) and forced expiratory volume in 1 s (FEV1) (r =.806) and forced vital capacity (FVC) (r =.781). Retention was more marked in sarcoidosis compared with tuberculosis (0.025 < p less t han or equal to 0.05). Radioaerosol lung imaging may reflect the pulmonary function impairment in parenchymal lung diseases. Retention of Tc 99m EL ma y be related to number of BAL cells or presence of a lymphocytic alveolitis . Long residency time of Tc 99m EL in the lungs implies that erythromycin c an also be administered by inhalation for therapeutic purposes. NUCL MED BI OL 26;6:695-698, 1999. (C) 1999 Elsevier Science Inc. All rights reserved.