Radio-Nuclide Explorations: Pyrophosphate Myocardial Imaging

A variety of radio-pharmaceuticals have been used to identify myocardial infarction. Most have been based on substances, such as fluorescein or tetracycline, that were known to concentrate in infarcted muscle and which were labelled with gamma-emitting radio-nuclides [21]. The observations of Shen and Jennings [22] indicating that calcium is deposited in crystalline or subcrystalline form in irreversibly damaged myocardial cells led Bonte and colleagues [23] to speculate that techne- tium-99m pyrophosphate (99mTc PYP) might prove suitable for infarct imaging. They reasoned that the PYP would complex with the calcium in the damaged cells. Their observations showed that the technique was a sensitive means of demonstrat­ing damaged myocardium.