Which of the following is NOT a noninvasive method for imaging the brain?

Positron Emission Tomography (PET) involves the injection of a radioactive tracer into the bloodstream, which makes it an invasive procedure. While it is a powerful imaging technique that allows researchers to observe metabolic processes in the brain, the use of radioactive substances requires careful handling and poses potential risks, distinguishing it from truly noninvasive imaging methods.

On the other hand, methods like Magnetic Resonance Imaging (MRI), Computed Tomography (CT), and Electroencephalography (EEG) do not involve such invasive steps. MRI uses strong magnetic fields and radio waves to generate detailed images of the brain, CT provides images through a series of X-ray measurements, and EEG records electrical activity along the scalp without any insertion or injections. Understanding the invasiveness associated with each technique is crucial for making informed choices in cognitive psychology research and clinical applications.