Multidisciplinary Nature of Medical Physics
Medical physics is one of several disciplines that have emerged from the growing interaction between physics and biology. Other such disciplines include biophysics, biomedical engineering, and health physics. Although the boundaries among these fields are by no means distinct, as a general guide, one may broadly state that biophysics concerns the use of physics in the study of basic biological mechanisms, that biomedical engineering concerns the development of new diagnostic instrumentation and prosthetic devices, and that health physics concerns the measurement of physical quantities that are related to environmental contaminants, especially ionizing radiation. The field of medical physics, on the other hand, may be defined broadly as "applied physics in medicine" and as such incorporates these other fields to the extent that they involve medical applications.
Diversity of Medical Physics
A feeling for the diversity of medical physics may be conveyed by listing some of the research and development problems with which medical physicists are concerned. These include:
- The study of basic mechanisms by which radiation transfers energy to biological materials.
- The development of new techniques for generating and detecting the various radiations used in medical science.
- The application of radioactive tracers in diagnostic medicine and in the study of metabolism.
- The optimization of physical parameters for particular tasks in diagnostic medical imaging (radiography, computed tomography, radionuclide imaging, magnetic resonance imaging, thermography, and ultrasonography).
- Dosimetry in radiation therapy.
- The measurement of pressures, flow, and oxygenation in cardiology,
- The recording and interpretation of bio-electric potentials in neurology.
- The analysis of diagnostic techniques in terms of information theory and communications theory.
- The development of computer aids in diagnostic imaging, image-guided therapy, and tumor response assessment.
Medical physicists engage in three broad areas of activity: clinical consultation, teaching, and research. Clinical activities include consultation with radiation oncologists in the planning and delivery of radiation treatments for cancer, consultation with radiologists and other physicians concerning the optimal use of medical imaging systems for the diagnosis of disease, the calibration of radiation sources, and the control of potential radiation hazards. Medical physicists participate in the teaching of resident physicians, medical students, graduate students, and technologists. Research opportunities open to medical physicists range from the development of instrumentation and quality control procedures in medical imaging and radiation therapy to the study of biomedical processes.
Most medical physicists are employed at universities and hospitals with a smaller number in research institutes, government health agencies, and industrial organizations. A few are self-employed, usually as consultants. Frequently, the hospital in which a medical physicist works is associated with a medical school, and the physicist is a member of the academic staff. A 2012 survey by the American Association of Physicists in Medicine, to which about 61% of the 5467 members who were emailed replied, showed that 1381 respondents had a Ph.D. and that 632 of the Ph.D. physicists worked in a medical school or university hospital setting; 72 percent were involved primarily in radiation therapy, with 15% in diagnostic radiology and 4% in nuclear medicine.
Demand for Medical Physicists
The demand for medical physicists has exceeded the supply for many years. Most large medical centers employ physicists, and many have vacancies on their staff. Many smaller hospitals also are seeking medical physicists. In spite of the recent downturn in the economy, the AAPM survey of 2012 reported a strong job market for medical physicists. The increasing use of physical instruments and techniques in medicine and the increasing interest in medical research serve to increase the demand for medical physicists. Thus, many factors contribute to make medical physics a creative, expanding, and rewarding profession for the young physicist about to choose a career.