A PET Scan measures brain activity by tracking what?

A PET Scan measures brain activity by tracking what?

• A. Radioactive glucose
• B. Magnetic fields
• C. Electrical waves
• D. Ultrasound

Answer: (A)

PET scans visualize brain activity by using a radioactive glucose tracer. Active brain regions burn more energy and take up more glucose, so after injecting the tracer those areas accumulate more of it. As the tracer decays, it emits positrons that the scanner detects, allowing a map of metabolic activity to be built. That’s why brighter (higher uptake) areas indicate greater activity. Other imaging methods rely on different signals: magnetic fields are used in MRI to image structure (and functional MRI looks at blood flow, not a radioactive tracer), electrical waves are measured by EEG/MEG, and ultrasound uses sound waves.

PET scans visualize brain activity by using a radioactive glucose tracer. Active brain regions burn more energy and take up more glucose, so after injecting the tracer those areas accumulate more of it. As the tracer decays, it emits positrons that the scanner detects, allowing a map of metabolic activity to be built. That’s why brighter (higher uptake) areas indicate greater activity.

Other imaging methods rely on different signals: magnetic fields are used in MRI to image structure (and functional MRI looks at blood flow, not a radioactive tracer), electrical waves are measured by EEG/MEG, and ultrasound uses sound waves.