Final answer:
A PET scan is a technique that tracks a radioactive tracer in the brain to visualize areas of activity during tasks, useful for diagnosing various conditions. The PET scan is different from an fMRI, which also maps brain activity but provides more detail and precision over time without radiation exposure.
Step-by-step explanation:
The visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task is best achieved through a PET scan (Positron Emission Tomography). A PET scan involves the injection of a mildly radioactive tracer, such as fluorodeoxyglucose (FDG), which the body uses similarly to glucose. As areas of the brain become more active, they require more blood and the tracer accumulates in those areas. A scanner detects the gamma radiation emitted after the tracer's radioactive atoms interact with electrons in the brain, which a computer then translates into a detailed, three-dimensional color image that highlights active and inactive regions of the brain during specific behaviors. While PET scans offer the advantage of visualizing brain functionality, which is useful in diagnosing conditions like Alzheimer's disease or epilepsy, they are less precise in time and offer less detail compared to techniques such as fMRI (functional Magnetic Resonance Imaging), which can also map brain activity over time by tracking blood flow and oxygen levels without exposure to radiation.