Medical physics (also called biomedical physics, medical biophysics, applied physics in medicine, physics applications in medical science, radiological physics or hospital radio-physics) is, in general, the application of physics concepts, theories, and methods to medicine or healthcare. Medical physics departments may be found in hospitals or universities.
In the case of hospital work, the term medical physicist is the title of a specific healthcare profession, usually working within a hospital. Medical physicists are often found in the following healthcare specialties: diagnostic and interventional radiology (also known as medical imaging), nuclear medicine, radiation protection and radiation oncology.

University departments are of two types. The first type are mainly concerned with preparing students for a career as a hospital medical physicist and research focuses on improving the practice of the profession. A second type (increasingly called 'biomedical physics') has a much wider scope and may include research in any applications of physics to medicine from the study of biomolecular structure to microscopy and nanomedicine. For example, physicist Richard Feynman theorized about the future of nanomedicine. He wrote about the idea of a medical use for biological machines (see nanobiotechnology). Feynman and Albert Hibbs suggested that certain repair machines might one day be reduced in size to the point that it would be possible to (as Feynman put it) "swallow the doctor". The idea was discussed in Feynman's 1959 essay There's Plenty of Room at the Bottom.