According to the American Association of Physicists in Medicine (AAPM), "Medical Health physics pertains to:

• the safe use of x-rays, gamma rays, electron and other charged particle beams of neutrons or radionuclides and of radiation from sealed radionuclide sources for both diagnostic and therapeutic purposes, except with regard to the application of radiation to patients for diagnostic or therapeutic purposes
• the instrumentation required to perform appropriate radiation surveys”

A medical physicist in this field ensures that the application of radiation and radioactivity by others is being used safely. He/she evaluates the equipment and its surrounding environment.

A certified medical physicist can specialize in one or more subfields of medical physics.