After reviewing this tutorial, the users should be able to describe the three methods of labeling red cells with Tc-99m, compare the advantages and disadvantages of each, and predict the labeling efficiencies obtained with each method; should be familiar with procedures suitable for preparing Cr-51 RBC's, Tc-99m WBC's. In-111 WBC's, and In-111 platelets and be able to state the most important indications for performing imaging procedures with these radiopharmaceuticals; should be able to identify the optimal labeling procedure for RBC labeling in special cases such as GI Bleeding studies or hemangioma localization; and should be familiar with special handling and anticoagulation techniques required for optimal labeling.