For several days after thyroid cancer patients receive treatment with radioactive iodine—the goal is to kill any thyroid tissue that remains after surgery—"their body fluids are radioactive, and they pose a risk to other people," says Jessica Clements, medical physics manager and radiation safety officer at Texas Health Presbyterian Hospital, Dallas (a part of the Texas Health Resources hospital system). The patients generally live at home during this phase of their treatment, and getting them through it without endangering family members and associates requires working with them to develop plans that take into account specific living arrangements, medical needs, and potential dangers to vulnerable people in the patient’s life, such as children.

Guiding patients through an intimidating procedure is just one of many patient-focused tasks that Clements regularly performs, but she doesn't hold a degree in medicine, nursing, or any traditional clinical field. Instead, with a master's degree in physics and certification from the American Board of Radiology, Clements is a medical physicist, a member of a small profession that plays an important role in health care, though not a very visible one. 

"If you're going to use an MRI scan or a CT scan or … do something like radiosurgery, you need a team of people, because nobody has the expertise to span neurosurgery, the medical portion of radiation oncology, and medical physics," says Frank Bova, professor of neurosurgery at the University of Florida medical school in Gainesville. Bova's Ph.D. is in nuclear engineering, with a specialization in medical physics. "Hospitals that have radiation oncology, diagnostic radiology, and nuclear medicine all have medical physicists."

Varied roles

Working at the intersection of physics and physic—of the physical and medical sciences—medical physicists fulfill a variety of roles. Medical physicists who hold Ph.D.s, like Bova, often focus on research in either academe or industry. Bova's research is highly practical: Members of his research group assist "the surgeons in the operating room in real time" with their expert knowledge of advanced imaging and radiation equipment, some of it developed in Bova’s lab.


Courtesy of the University of Florida
Frank Bova

The great majority of practicing medical physicists, however, closely resemble Clements: They hold professional certification based on a master's degree, have done a residency, and have passed written and oral certification exams. Most—the great majority, in fact—work in hospitals and other health care facilities where they contribute to diagnosis and treatment, Bova says.

About 85% of medical physicists are involved with "some form of therapy," according to Physics Today, a publication of the American Institute of Physics. That's an important aspect of the job for many who have chosen this career. "There is an absolutely rewarding feeling of being responsible for the treatment of cancer," says Tyler Fisher, a master's-level medical physicist in Gardena, California, who has experience working with hospital patients undergoing cancer treatment. "It is a noble calling." People doing this work—therapeutic medical physicists—"work behind the scenes making sure that the equipment is operating properly and that the treatment that the doctor wants can actually be delivered."

These days, Fisher prefers the challenge and variety of working as a consultant in the area of the profession known as diagnostic medical physics, evaluating and certifying the safety and accuracy of devices including MRI, CAT, and bone density scanners; mammography machines; and more. About 10% of medical physicists specialize in this branch, according to Physics Today, many of them working for hospitals or healthcare systems. Fisher also advises architects on designing proper shielding for imaging equipment in new health care facilities.

The remaining 5% of medical physicists work with nuclear materials that are frequently used in medicine, Physics Today states. Many peoples' responsibilities encompass more than one specialty, Clements adds.


Courtesy of Tyler Fisher
Tyler Fisher

Promising prospects

Certification as a medical physicist requires at least a master's degree from a specialized 2-year graduate program covering physics, biology, and medicine; several dozen such programs have been accredited by the Commission on Accreditation of Medical Physics Education Programs (CAMPEP). "To participate fruitfully in this interdisciplinary profession," states the website of the University of Chicago's medical physics program, a medical physicist "must be thoroughly competent in physical and mathematical science, must understand biological and physiological systems, and must be able to understand and speak the language of physicians."

Admission to a medical physics graduate program requires an undergraduate major in physics or a closely related field. In choosing a graduate school, Fisher advises, prospective students should consider the varying emphases of particular programs—but "the most important aspect" is CAMPEP accreditation, which is required to gain admission to the 2-year residency that medical physicists must complete to take the certification exams.

Competition for residencies has increased in recent years, inspiring, some universities to develop what Clements calls a "new pathway" into the profession: a 4-year professional doctorate in medical physics (DMP) that includes 2 years of academic study and 2 years of residency. Placement in a residency is guaranteed.

A DPM degree does not "provide the research credentials necessary for a research Ph.D. degree," notes the website of Vanderbilt University's DMP program. Conversely, a research Ph.D. does not provide access to the medical physics profession. People with Ph.D.s in physics, engineering, or computer science can, however, make that switch and become medical physics practitioners via 1-year programs that prepare doctorate holders to enter residencies. As of January 2014, 11 such programs had attained CAMPEP accreditation. At least one additional institution offers a 3-year program that includes a residency. Admission to degree and certificate programs is quite competitive. Some financial assistance is available in the form of assistantships and research stipends. 

Once medical physicists gain certification, "career prospects are very bright. ...There is enormous demand right now for qualified people," Fisher says. Salaries are "great" and have been "rising routinely for years." According to information supplied by the American Association of Physicists in Medicine, in 2012 certified medical physicists with master's degrees earned a median salary of $178,000, about a 3% increase over the previous year. Ph.D.s with certification earned a median salary of $185,000, also with about a 3% raise over the previous year.

The excellent pay was "a really good bonus, [but] not why I got into" the field, says Clements, who entered college expecting to take a premedical curriculum. That was before one of her physics professors got treatment at the University of Texas MD Anderson Cancer Center in Houston, and returned to campus telling students about the 100 medical physicists who worked there. Intrigued, Clements arranged to shadow a medical physicist to learn about the profession. The profession's combination of "the scientific element [with] the human element of health care" won her over. Today, she and the three medical physicists she supervises do therapeutic and diagnostic medical physics at 14 of the hospitals in a 25-hospital system.

An additional plus for Clements is that, in contrast to some physical science fields, medical physics is "very welcoming" to women. "Historically, it was about 20 percent female. Anecdotally I hear that graduate programs are about 50-50 men and women. … A lot more women [are] coming into the field in the last 20 or so years."

Top Image: Jessica Clements. Courtesy of Jessica Clements

Beryl Lieff Benderly writes from Washington, D.C.

10.1126/science.caredit.a1400105