Abstract: | 51Cr sodium-chromate, though having been widely used in the last two decades for labeling platelets, suffers from several serious drawbacks, ie, low labeling efficiency, long physical half-life, and low gamma photon yields. 111In-oxine and 111In-tropolone overcome these shortcomings and have the potential of precise determination of platelet kinetics as well as visualization and in vivo quantification of the temporal and spatial distribution of platelets in man. Computer analysis of platelet kinetics reveals that the multiple-hit model fits the survival curve better than the linear or the exponential model. The multiple-hit model provides not only the mean platelet survival time but also information on the initial recovery and the shape of the survival curve. The application of these techniques in normal and disease states should greatly enhance our understanding of the physiology and pathophysiology of platelets. |