The present invention provides a compound that has high accumulation in a heart disease site and is suitable as a tracer for nuclear medical examination of positive electron computed tomography. By using the compound, it can detect heart disease in the body and provide the following chemical formula ( 1) A non-invasive imaging diagnostic agent for heart disease with the indicated compound or its salt as an active ingredient. In the chemical formula, X 1 represents a hydrogen atom or a halogen atom, X 2 represents a fluorine atom or a nitrile group, and X 3 represents a radioactive fluorine atom. 》本發明，提供在心臟病變部位有高的蓄積性、適合作為正子電腦斷層攝影的核子醫學檢查的追蹤劑（tracer）的化合物，藉由使用該化合物，可以檢測體內心臟病變，提供含有下列化學式(1)所表示之化合物或其鹽類作為有效成分的心臟病的非侵入性影像診斷劑。《化學式中，X1係表示氫原子或鹵素原子，X2係表示氟原子或腈基（nitrile group），X3係表示放射性氟原子。》
