What imaging technique measures brain function by detecting radioactivity from positrons?

Positron Emission Tomography (PET) is the imaging technique that measures brain function by detecting the radioactivity emitted from positrons, which are the antiparticles of electrons. In a PET scan, a radioactive tracer is injected into the bloodstream. This tracer usually comprises a biologically active molecule, such as glucose, that emits positrons as it decays. When these positrons encounter electrons in the body, they annihilate each other, resulting in the emission of gamma rays.

The scanner then detects these gamma rays and uses them to create images that show areas of high metabolic activity in the brain. This is crucial for understanding brain function, as active areas will have higher radiotracer uptake, allowing researchers and physicians to assess how different regions of the brain are functioning during various tasks or in conditions like tumors or neurodegenerative diseases.

In contrast, Magnetic Resonance Imaging (MRI) focuses on anatomical details using magnetic fields and radio waves, Computed Tomography (CT) creates detailed cross-sectional images through X-ray technology, and Electroencephalogram (EEG) measures electrical activity in the brain but does not provide insight into metabolic function like PET does.