PET Imaging CCR2 in Lung Inflammation

This study is using a new type of PET scan to measure a specific type of immune cell (called CCR2-positive monocytes) in the lungs of both healthy people and smokers, to better understand inflammation in the lungs before it causes visible disease — potentially leading to earlier detection of lung damage. **You may be eligible if...** - You are 21 or older - You are either a never-smoker in good health, OR a current smoker who smokes at least half a pack per day and has smoked at least 5 packs over the past month - Your lung function test (spirometry) is normal (FEV1 and FVC above 80% of expected) - You have no known heart, lung, liver, kidney, or metabolic diseases - You can lie still in a scanner for about 1 hour - Your BMI is 35 or lower - You do not take any prescription medications **You may NOT be eligible if...** - You are pregnant - You are enrolled in another study using an investigational drug - You have any active heart, lung, liver, or kidney condition or diabetes - You have used illicit drugs or other inhaled substances in the past year - You have a pacemaker or other implants that are incompatible with CT or MRI - Your kidney or liver blood tests are outside acceptable ranges Talk to your doctor to see if this trial is right for you.