fMRI
Functional MRI (fMRI) is cheaper, simpler and more sensitive than PET scanning, and does not use radioactivity. For an fMRI scan, the person lies inside a huge magnet - as strong as the ones used to pick up scrap cars. fMRI shows up areas of the brain with an increased oxygen supply (more active brain tissue uses more oxygen). It relies on the fact that molecules in blood cells respond differently to magnets depending on how much oxygen they are carrying.
