A diagnosis of RAI‐R thyroid cancer was based on the presence of multiple metastatic sites revealed with 18F‐FDG uptake in the first PET/CT scan conducted in April 2018. Diffuse lesions in soft and muscular tissues, multiple 18F‐FDG uptake in bones, and a large target lesion in the left lung were observed (arrow) (transverse view). 18 F‐FDG, 2‐deoxy‐2‐[fluorine‐18] fluoro‐D‐glucose; PET/CT, positron emission tomography/computed tomography; RAI‐R, radioiodine refractory 