The concentration of 125I-phenylphosphate (IPA), a long-lived bone-seeking radio-pharmaceutical (T1/2 biol = 962 days) that localizes in acute infarction (MI), was studied in 30 rats after ligation of the anterior descending coronary artery. At 23 h postMI, IPA was given intravenously to all animals, and five of this group received 99Tcm-pyrophosphate (99Tcm-pyro) intravenously. These five rats were sacrificed 2 h later and the content of IPA and 99Tcm-pyro activities was determined for normal and infarcted (INF) heart segments.
There is a zone of INF that contains residual IPA which also concentrates 99Tcm-pyro consistently after MI. This zone may represent jeopardized myocardium which has not undergone complete necrosis.
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