TIO shows impaired bone metabolism due to excessive actions of FGF23 produced by the tumor. The causative tumors are seldom detected by physical examinations and conventional radiological modalities.In TIO cases, in which the localization of the culprit tumors is difficult, 68 Ga-DOTATOC-PET/CT should be performed as a screening of localization and thereafter SVS should be conducted to support the result of the somatostatin receptor (SSTR) imaging leading to increased diagnosability.When the culprit tumors cannot be visualized by conventional imaging studies, using high-field MRI at 3T and comparing it to the opposite side are useful after the tumor site was determined.