Rosalyn Yalow

Rosalyn Sussman Yalow was an American medical physicist who developed the radioimmunoassay technique, a highly sensitive method for measuring minute concentrations of hormones and other substances in the blood. In 1977 she shared the Nobel Prize in Physiology or Medicine with Roger Guillemin and Andrew Schally, becoming the second woman, after Gerty Cori, and the first American-born woman to receive the prize in that category.