Images internal body structures. Operates by contrasting different atoms' behavior in strong magnetic fields. Measures brain activity to diagnose disorders. Detects decays of radioactive tracers in the bloodstream to form active images. PET is used to diagnose changes in brain activity due to mental illness, drug use, or diseases such as Alzheimer's and Parkinson's.
Mammograms use low doses of x-rays to detect breast cancer.
Several million MRI scans are performed annually. NSF and NIH are among the supporters of this work. Superconducting magnets, faster computers, and new detectors, all federally funded, are used for MRI, leading to faster, more highly resolved scans of the body. Functional MRI is developed, capable of resolving the brain in action and identifying the brain activity centers of diseases such as epilepsy.