A case of 18F-FDG PET in pulmonary alveolar microlithiasis with bilateral reticulonodular opacities in the middle and lower zones on routine chest roentgenogram and calcification in the peribronchovascular interstitium,peribronchovascular and subpleural intralobular septal regions, and visceral pleura on high-resolution chest CT is presented. 18F-fluoride PET demonstrated intense tracer uptake in the lower zone of both lungs corresponding to CT findings. Minimal FDG activity in areas of dense calcification suggests minimal or no inflammation. This could account for the absence of symptoms in most cases despite remarkable imaging findings.