Radioactive Tracers

The process of obtaining an image from a radioactive tracer is called scintigraphy. Other imaging techniques (computerized tomography, CT; magnetic resonance imaging, MRI) give anatomical information. Scintigraphy gives information on the movement of compounds through tissues and vessels, and on metabolism. Earlier diagnosis is possible with scintigraphy because chemical changes often occur before structural ones. For example, a CT brain scan can be normal 48 hours after a stroke, but shows immediate changes.