Renowned medical physicist Rosalyn Sussman Yalow, a co-recipient of the 1977 Nobel Prize in Physiology or Medicine, died on 30 May 2011 in New York City.

Rosalyn was born on 19 July 1921 in New York City. Although her parents were not able to attend high school, they passed down to Rosalyn their lifetime love of learning. Her fondness for chemistry was influenced by her high school chemistry teacher. In 1941 she became the first physics graduate of Hunter College, part of the City University of New York system and at that time a women’s college. Her love of physics was inspired by two of her professors there.

In pursuing a graduate education, Rosalyn faced several obstacles: She was a woman in a man’s field, she was Jewish, and she spoke with the broad accents of New York City. With her usual determination, however, she was able to attend graduate school at the University of Illinois at Urbana-Champaign, where she started in 1941. Of the 400 people in the College of Engineering, she was the only woman. Maurice Goldhaber, who would later direct Brookhaven National Laboratory, served as her adviser. In 1943 she married physics graduate student Aaron Yalow, also a New Yorker and the son of a rabbi. Two years later Rosalyn received her PhD in nuclear physics—much of her research involved radioactivity. She received encouragement from Gertrude Goldhaber, a practicing physicist married to Maurice.

After graduate school, Rosalyn took a job in New York at an ITT laboratory until it left the area a year later. She then returned to Hunter, this time to teach. Aaron, who by that time had joined Montefiore Hospital in the Bronx, introduced her to Edith Quimby, a trailblazer in medical physics. Quimby brought together Rosalyn and Gioacchino Failla, a pioneering biophysicist at Columbia University, who was very impressed with Rosalyn. Failla then convinced Bernard Roswit, chief of radiation therapy at the Bronx Veterans Administration Hospital, to hire her. She would spend her entire career in the VA hospital system.

In 1950, while at the Bronx VA Hospital, she began her 22-year collaboration with internist Solomon Berson. Together they developed radioimmunoassay, a revolutionary technique that uses radiolabeled antibodies to measure antigens. They focused their research on the clinical diagnosis of thyroid diseases and the kinetics of iodine metabolism. The team developed an interest in serum proteins. At a time when highly purified insulin was readily available, Rosalyn and Berson soon determined that patients treated with animal insulins built up antibodies to them. They recognized that they had in their hands a means to measure circulating insulin. By 1959 they were able to put to practical use the measurement of plasma insulin in humans. Radioimmunoassay testing has now been largely replaced with fluorescent techniques; however, immunoassay is still used in routine blood tests.

Berson died in 1972 and never saw the full recognition of his and Rosalyn’s work. In 1976 Rosalyn was presented with the Albert Lasker Basic Medical Research Award, considered by many to be a precursor to the Nobel Prize. The following year she was a co-recipient of the Nobel Prize in Physiology or Medicine. She was again recognized in 1988, this time with the National Medal of Science, for her groundbreaking work.

Rosalyn and Aaron were deeply involved in the establishment of organizations dedicated to medical physics. In 1948 they helped found the Radiological and Medical Physics Society of New York, and in 1958 they became charter members of the American Association of Physicists in Medicine.

Rosalyn took great pride in the many physicians and scientists that she and Berson mentored. Later in life, to ease the public’s fears about radiation exposure, she spoke in numerous US venues on the topic.

Some 70 years after Rosalyn was the only woman in her graduate program, it is tantalizing to ask how things have changed. She would be the first person to start that discussion. She had made it her mission to inspire talented women in their pursuit of science and mathematics careers. Although Rosalyn would never classify herself as a feminist, many women scientists saw her as a role model, just as she viewed Marie Curie. Those of us to whom she has passed the torch have lost a champion and mentor. We will try to live up to her challenge.

Rosalyn Sussman Yalow