What is Medical Physics?

Medical physics is the application of physics to medicine. It generally concerns physics as applied to medical imaging and radiotherapy, although a medical physicist may also work in many other areas of healthcare. A medical physics department may be based in either a hospital or a university and its work is likely to include research, technical development and clinical healthcare.

Of the large body of medical physicists in academia and clinics, roughly 85% practice or specialize in various forms of therapy, 10% in Diagnostic imaging, and 5% in nuclear medicine. Areas of specialty in medical physics however are widely varied in scope and breadth.

Clinical medical physicists are a very important part of the radiation oncology team. Their primary role is to assure that the highest level of quality care is maintained. The medical physics group design and implement the quality assurance program in radiation oncology. They are responsible for selecting and specifying the types of equipment that are used in radiation therapy. After new equipment is installed, the medical physicist assures that the equipment meets or exceeds specifications.


Once the equipment is accepted, the physicist is responsible for commissioning the equipment, which involves taking enough measurements so that the equipment can be used clinically. Measurement data must also be transferred to other computer systems so that patient treatments can be planned. The medical physicist is frequently consulted by the radiation oncologist to help design a treatment that is difficult or unusual. A physicist is responsible for doing the quality assurance of every treatment plan before it starts. He or she checks that the planned information has been correctly transferred to the machine, that the plan agrees with the physicians prescription, that beam-on times are correct for each treatment field, and that all information is consistent, understandable, and well-documented.