Medical physicists work in cooperation with doctors. A few medical physicists devote their time to research and teaching. A few get involved with administrative duties.
Too many radiologists still believe there is a risk from a chest x-ray. Few radiologists can explain radiation to the patient in words the patient can understand.
Most medical physicists work in the physics of radiation oncology making sure that the desired dose is given to the cancer and the dose to normal tissues are minimized.