Nuclear Medicine can attach its tracer to red blood cells.  Several of our studies utilize this kind of "tagged RBC" method.  Among them are:  Gastrointestinal Bleeding scans, Liver Hemangioma Scans, Red Blood Cell Volume studies and MUGA scans.  Although they all use tagged red blood cells, they are performed very differently and are not interchangeable.   
Also, we can image several organs - such as the liver - using multiple techniques.  For example, we can look for liver hemangiomas with tagged RBCs, or look for liver and splenic function using Technetium labeled sulfur colloid.  Although the names of these scans are similar, they look at very different processes and/or organs in the body.