A 56-year-old man who had diffuse bone pain and weight loss for 1 year underwent FDG PET/CT and a dual-tracer, dual-phase parathyroid imaging. The FDG PET/CT scan showed foci of increased metabolism in several bones and the stomach, which were proven histologically as brown tumor and gastritis. The planar images of parathyroid imaging revealed only thyroid nodule, whereas the tomographic imaging demonstrated both the thyroid and the parathyroid adenomas, which were confirmed by surgical pathology.