Medical physicists play an essential role in enabling many different types of radiation to be used for the diagnostic and therapeutic benefit of the patient without danger to the staff or to members of the public. This includes the use of diagnostic X-ray, radiotherapy, radioisotopes, lasers and ultraviolet radiation.

Measurements and calculations of doses received by patients and staff, surveys of the working environment, and monitoring of equipment involving radiation are all used to provide evidence of good working practice and compliance with the regulatory requirements governing the uses of radiation.   Such types of dosimetry present special problems because of the low levels of radiation that can be encountered.  In most medical physics departments, the radiation protection work is carried out by staff with prior or concurrent experience of the diagnostic and therapeutic applications of radiation.

Certain senior medical physicists are designated as Radiation Protection Advisers to advise employing authorities on all matters concerning radiation protection. 
When new equipment, buildings or updated techniques are introduced, whether in diagnosis or treatment, the Radiation Protection Adviser gives expert advice aimed at achieving an optimal exploitation of advances in radiation science and technology, taking into account not only the possible hazards but also the potential benefits to the patient.

Advice is also given on the most safe and optimum way of disposing used radioactive materials and waste products resulting from the administration of radioactive materials to patients for diagnostic or therapeutic purposes.

The tragic episode at Chernobyl demonstrated the value of a radiation protection organisation working with the hospital service and able to make measurement and give informed advice including, where appropriate, reassurance to patients and members of the public following any accidental release of radioactivity.

link to IAEA Radiological Protection of Patients