What is Medical Physics?

Medical physicists are professionals with expertise in the various types of radiation used to diagnose and treat disease. They work with physicians and other clinical personnel to ensure that radiation is used safely and effectively in the healthcare environment.

High-tech imaging is an integral part of modern health care. CT, PET, and MRI scanners in particular have become invaluable tools for imaging patient anatomy and identifying disease. (This field of medicine is known as “diagnostic imaging.”) Medical physicists are closely involved in the calibration and operation of these scanners to help optimize image quality and minimize safety risks.

Radiation oncology is the treatment of cancer using ionizing radiation emitted by either machines or radioactive materials. Linear accelerators (“linacs”) are widely used for on-demand generation of penetrating beams of photons or electrons, while radioactive materials or small x-ray devices are sometimes placed inside or close to patients for short-range irradiation of certain tumors. One important responsibility of medical physicists is accurately measuring the output from these radiation-emitting sources in order to ensure that correct doses are administered during treatment. Medical physicists are also often closely involved in the planning, checking, and delivery of radiation treatments.

Medical physicists help ensure accurate delivery of desirable radiation to patients while keeping unwanted radiation doses to patients, medical personnel, and the public at safely low levels. This work has many aspects, including:

• Making sure radiation-emitting devices and materials are properly measured and calibrated.
• Designing treatment approaches that optimize radiation delivery.
• Designing the shielding around radiation-emitting devices and materials to best protect occupational personnel and the public.

Modern medicine is continually improving due to advances in science and technology. Medical physicists play a vital role in research and development over a wide range of areas and at all levels, from basic science to clinical applications. Such work can take place in hospitals, universities, and industry.

Medical technologies have benefited enormously in recent years from increasingly powerful computers and sophisticated software. Many medical physicists are working in this computing space, applying cutting-edge techniques in machine learning and information theory to improve diagnostic imaging and interpret treatment outcomes. Other physicists are working to improve the accuracy and speed of dose-calculation algorithms to generate better radiation treatment plans more quickly. Yet others are working to bring new information technologies into the clinic to improve workflows and communications among healthcare teams.

Medical physicists are also involved in the development of new instruments, technologies, and techniques, most often in the fields of diagnostic radiology and radiation therapy. Examples include new imaging procedures utilizing infrared or ultrasound sources; the use of nanoparticles to enhance diagnostic imaging or even radiosensitivity during therapy; innovative radiation delivery techniques that enable more sophisticated and precise treatments; and novel devices that improve the quality of clinical treatment.

Some physicists even study the biological effects of radiation (radiobiology) or the distribution of radioactive substances in the body over time (pharmacokinetics).