n :  a medical imaging technique that is used esp. for mapping brain function and that is similar to positron-emission tomography in using the photons emitted by the agency of a radioactive tracer to create an image but that differs in being able to detect only a single photon for each nuclear disintegration and in generating a lower-quality image - abbr. SPECT .
 
 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2024.