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Improving Health Through Medical Physics

AAPM Statement on Quality Radiation Therapy

January 27, 2010

The American Association of Physicists in Medicine (AAPM) is a scientific and professional organization composed of scientists (medical physicists) whose clinical practice is dedicated to accuracy, safety and quality in radiation oncology, medical imaging, image-guided medical procedures and medical radiation safety. Articles published recently in the New York Times have focused on rare events in radiation therapy that have resulted in tragic consequences for patients. The AAPM and its members deeply regret that these events have occurred, and we continue to work hard to reduce the likelihood of similar events in the future.

Radiation Therapy

Each year in the United States, hundreds of thousands of people with cancer receive radiation therapy, amounting to tens of millions of radiation therapy treatments. Clinical trials have conclusively demonstrated the benefits of radiation therapy for curing cancer and for alleviating pain and suffering.

The medical team in radiation therapy includes radiation oncologists, medical physicists, dosimetrists, radiation therapists and nurses, all dedicated to working cooperatively to provide optimum care of the patient. These individuals work within a system where quality measures are designed to prevent errors and failures from affecting patients. Even with this system in place, errors occasionally occur.  As suggested in recent reports, radiation treatment errors that could have adverse effects on patients occur in a very small number of radiation treatments (1, 2). In most cases, these effects do not lead to permanent injury.  Consequences like those reported recently in the press occur exceptionally rarely – although the AAPM and its members agree that they should never occur.

Medical Physicists

Medical physicists are responsible for quality assurance and the technical aspects of the complex technology used to treat patients with radiation. The medical physicist’s primary professional responsibility is to the patient’s safety and welfare. Qualified Medical Physicists have a unique combination of education and training in physics principles, radiation physics applications, the technologies of treatment delivery, dose planning and measurement, radiobiological principles, human anatomy and oncology principles, as well as safety analysis and quality control methods.

In the United States, medical physicists demonstrate competence in their discipline by obtaining board certification. Certification is a rigorous, multi-year process that requires considerable clinical experience under supervision and passage of written and oral examinations.  Medical physicists follow detailed quality assurance and safety protocols established to insure that cancer treatments with radiation are conducted according to the prescription prepared by the physician for every treatment of every patient. Medical physicists follow guidance from national standards documents developed by the AAPM and in cooperation with other professional societies. The AAPM has numerous committees dedicated to quality assurance and safety in radiation therapy.

Education on Quality and Safety

The AAPM provides educational symposia and courses on the reduction and prevention of errors in radiation therapy. The AAPM works with several other professional societies, equipment manufacturers and regulatory agencies to develop national guidance for quality assurance and safety (3). A national summit is being organized by the AAPM to identify ways to enhance the safety and effectiveness of using complex technologies to administer radiation to humans for the treatment of cancer.  Medical physicists, radiation oncologists, dosimetrists, radiation therapists, manufacturer and vendor representatives, and members of public interest groups will be invited to the summit.


Radiation therapy provides safe and effective treatment of cancer and other diseases for hundreds of thousands of people each year. Very rare events with tragic consequences serve as a poignant reminder that treatment is not without risk. We remain committed to identifying and implementing improvements in patient safety in order to enable us to continue to offer high quality, safe and effective radiation treatments for every patient in the fight against cancer.

AAPM Executive Committee

(1) The American Society for Radiation Oncology Letter to the New York Times, 1/25/2010. 

(2) Towards Safer Radiotherapy, British Institute of Radiology, 2008.

(3) AAPM has published a number of quality specific documents for the technical aspects of radiation therapy at In addition AAPM has sponsored national quality assurance conferences, most recently in 2007 ; Int. J. Radiation Oncology Biol. Phys., Vol. 71, No. 1, Supplement, p. S1, 2008.