Matrix metalloproteinases (MMPs) are the main proteolytic enzymes involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). A radiolabeled MMP inhibitor, [F-18]FB-ML5, was prepared, and its in vivo kinetics were tested in a mouse model of pulmonary inflammation. BALB/c mice were exposed for 4 days to cigarette smoke (CS) or air. On the fifth day, a dynamic microPET scan was made with [F-18]FB-ML5. Standardized uptake values (PET-SUVmean) were 0.19 +/- 0.06 in the lungs of CS-exposed mice (n = 6) compared to 0.11 +/- 0.03 (n = 5) in air-exposed controls (p <0.05), 90 min post-injection MMP-9 levels in bronchoalveolar lavage fluid (BALF) were increased from undetectable level to 4615 +/- 1963 pg/ml by CS exposure. Increased MMP expression in a COPD mouse model was shown to lead to increased retention of [F-18]FB-ML5.