Curie, now known as the Mother of Modern Physics, was the first woman to win a Nobel Prize, the only woman to win in two fields, and the only person to win in multiple sciences. She completed her Ph.D. thesis "Recherches sur les substances radioactives" in 1903, the same year that she shared the Nobel Prize in physics with her husband, Pierre and physicist Henri Becquerel. Her achievements included a theory of radioactivity (a term that she coined), techniques for isolating radioactive isotopes, and the discovery of two elements, polonium and radium. Under her direction, the world's first studies were conducted into the treatment of neoplasms, using radioactive isotopes. She founded the Curie Institutes in Paris and in Warsaw, which remain major centres of medical research today.