Which imaging method is primarily used to measure brain metabolic activity with radioactive tracers?

Which imaging method is primarily used to measure brain metabolic activity with radioactive tracers?

• A. fMRI measures blood flow
• B. PET measures metabolic activity
• C. EEG measures electrical activity
• D. CT measures bone density

Answer: (B)

PET imaging uses radioactive tracers to map metabolic activity in the brain. A common tracer, FDG, is a glucose analog that is taken up more by metabolically active neurons. After injection, areas with higher energy use accumulate more tracer, and the emitted positrons are detected to create an image showing which regions are more metabolically active. This direct link to metabolism is what makes PET particularly suited to measuring metabolic activity with tracers. In contrast, fMRI tracks changes in blood flow and oxygenation as a proxy for neural activity, not metabolism traced by radioactivity. EEG records electrical signals from neurons, which tells you about timing of activity but not metabolic processes, and CT provides structural images such as bone density without assessing metabolic function.

PET imaging uses radioactive tracers to map metabolic activity in the brain. A common tracer, FDG, is a glucose analog that is taken up more by metabolically active neurons. After injection, areas with higher energy use accumulate more tracer, and the emitted positrons are detected to create an image showing which regions are more metabolically active. This direct link to metabolism is what makes PET particularly suited to measuring metabolic activity with tracers.

In contrast, fMRI tracks changes in blood flow and oxygenation as a proxy for neural activity, not metabolism traced by radioactivity. EEG records electrical signals from neurons, which tells you about timing of activity but not metabolic processes, and CT provides structural images such as bone density without assessing metabolic function.