Libby's physician refers her to a medical center in order to have the biochemical activity in her brain analyzed. She is given an injection of a radioactive glucose-like substance and then is told to lie down with her head in a scanner

The technique being used is
A) positron emission tomography.
B) functional magnetic resonance imaging.
C) microelectrode recording.
D) an electroencephalogram.

Answer: A
Rationale: Positron Emission Tomography (PET) scans use low levels of radioactive glucose that is injected into the blood to visualize which areas of the brain are engaged by various tasks (active nerve cells use up the glucose at a faster rate than do resting cells).