Radioactive Tracers

Tomography uses computer technology to convert numerous planar images into a three-dimensional slice through the object. This data processing is also used with CT and MRI. With radioactive tracers, it is called emission computed tomography, which includes single photon emission computed tomography (SPECT) and positron emission tomography (PET). Positrons result from a different type of radioactive decay which we will not discuss here.

SPECT images are usually obtained with Anger cameras which rotate around the patient. Numerous images are obtained at different angles. Faster and bigger computers give better image quality, while improved graphics capabilities allow three-dimensional imaging. These are helpful in precisely locating areas of concern within an organ, but are more expensive and take longer to obtain. Hence, both planar and SPECT images will continue to be obtained.