To provide: a radionuclide-labeled compound having both tau protein affinity and amyloid protein affinity； an imaging agent that contains the radionuclide-labeled compound and that is used for imaging tau proteins and/or amyloid proteins； and a radioactive medicine that contains the radionuclide-labeled compound and that is used for diagnostic imaging of diseases caused by the aggregation of tau proteins and/or amyloid proteins.SOLUTION: The present invention provides radionuclide-labeled compounds represented by general formula (1) or salts thereof. (In the formula, X represents a radioactive iodine atom,F orCH； pyridine and oxazole are bound by a carbon atom； and pyridine is bound to imidazopyridine by a carbon atom.)SELECTED DRAWING: None【課題】タウ親和性とアミロイド親和性を併せ持つ、放射性核種標識化合物；放射性核種標識化合物を含む、タウ及び／又はアミロイドの画像化に用いられる、イメージング剤；放射性核種標識化合物を含む、タウ及び／又はアミロイドの凝集に起因する疾患の画像診断に用いられる、放射性医薬の提供。【解決手段】下記一般式（１）で表される放射性核種標識化合物又はその塩。（式中、Ｘは放射性ヨウ素原子、18Ｆ又は11ＣＨ3を示し、Ｐｙｒｉｄｉｎｅとｏｘａｚｏｌｅは炭素原子で結合しており、Ｐｙｒｉｄｉｎｅは炭素原子でイミダゾピリジンと結合している）【選択図】なし
