Compared with PET, which statement about fMRI is true?

Compared with PET, which statement about fMRI is true?

• A. It measures electrical activity directly
• B. It uses radioactive tracers
• C. It does not use radiotracers and has no ionizing radiation
• D. It has poorer temporal resolution than PET

Answer: (C)

The main idea being tested is how fMRI differs from PET in what it measures and how it works. fMRI detects brain activity by measuring changes in blood oxygenation and flow, using magnetic resonance imaging, and it does not involve radioactive tracers or any ionizing radiation. This non-radioactive nature is a key distinction from PET, which relies on radiolabeled tracers to image metabolic processes. Because fMRI relies on the slower vascular response rather than tracer kinetics, its temporal resolution is limited by blood flow dynamics but is still generally better than PET’s. So, the statement that fMRI does not use radiotracers and has no ionizing radiation is the accurate one.

The main idea being tested is how fMRI differs from PET in what it measures and how it works. fMRI detects brain activity by measuring changes in blood oxygenation and flow, using magnetic resonance imaging, and it does not involve radioactive tracers or any ionizing radiation. This non-radioactive nature is a key distinction from PET, which relies on radiolabeled tracers to image metabolic processes. Because fMRI relies on the slower vascular response rather than tracer kinetics, its temporal resolution is limited by blood flow dynamics but is still generally better than PET’s. So, the statement that fMRI does not use radiotracers and has no ionizing radiation is the accurate one.