<qa>  How many hours post-infusion will blood samples for radioactivity measurements be drawn?Blood samples for radioactivity measurements will be drawn immediately before infusion and at approximately 0, 0.5, 1, and 2 hours post-infusion, and then 6 more samples will be drawn at 1, 2, 3, 4 or 6, 7, and 111 days post-infusion, at approximately the same time of day as the radiolabeled platelet infusion was administered 4 hours. 