This is a proposal to evaluate the utility and accuracy of emission tomographic techniques using single photon emitting radionuclides (not positron emitters) for the quantification of myocardial infarct size using the two techniques of: (1) coded aperture imaging and (2) emission computed tomography. These techniques will be used to image and quantify the uptake of infarct avid radiopharmaceuticals such as technetium pyrophosphate and radiopharmaceuticals which localize in the myocardium in proportion to blood flow such as thallium-201. These techniques will be developed further and their spatial and quantitative accuracy assessed in a quantifiable dog model for myocardial infarction and then extended to human studies where their accuracy will be compared to conventional methods for infarct sizing and when possible correlated with post-mortem measurements of infarct size and location.