After immigrating to the United States in 1941, she was granted a Carnegie Fellowship to continue her research and provided technical information on her polonium extraction methods to the Manhattan Project.

Her father was a prosperous Jewish physician who worked with Louis Wickham and Henri-August Dominici, founders of radium therapy, to introduce the techniques to Budapest,[3] and installed one of the first x-ray machines there.

Rona first coined the terms "isotope labels" and "tracers" during this study, noting that the velocity of diffusion depended on the mass of the nuclides.

Owing to political instability and the persecution of those with communist sympathies during the countering White Terror, an increasing amount of work at the Institute fell to Rona.

[7] Hyperinflation in the Weimar Republic forced her transfer to the Textile Fiber Institute of Kaiser Wilhelm, as practical research was the only work permitted at the time.

[11] As early as 1926, Meyer had written to Irène Joliot-Curie suggesting that Rona work with her to learn how his laboratory could make their own polonium samples.

Once Hans Pettersson was able to secure funds to pay Rona's expenses, Joliot-Curie allowed her to come and study polonium separation at the Curie Institute in Paris.

[11] Her skills were in high demand and she formed many collaborations in Vienna, working with Ewald Schmidt on the modification of Paul Bonét-Maury's method of vaporizing polonium; with Marietta Blau on photographic emulsions of hydrogen rays;[14] and with Hans Pettersson.

[7] Her analyses with Berta Karlik on the half-lives of uranium, thorium, and actinium decay identified radiometric dating[7] and elemental alpha particle ranges.

Soon after, Curie died and Rona became ill, but she was able to return to Vienna late the following year[14] to share what had been learned with a group of researchers made up of Pettersson, Elizabeth Kara-Michailova, and Ernst Føyn, who was serving as an assistant to Ellen Gleditsch at that time.

[16] In 1935 Rona consolidated some of these relationships, working on Stora Bornö, then visiting Gleditsch in Oslo, then traveling to Copenhagen to see Hevesy, and later to Kålhuvudet, Sweden to meet with Karlik and Pettersson.

[20] Faced with encroaching Russians on one side[20] and the Nazi involvement in Hungary during World War II on the other, in early 1941 Rona obtained a visitor's visa and fled to the United States.

[7] Between 1941 and 1942, she conducted work at Carnegie in conjunction with the Woods Hole Oceanographic Institution, measuring the amount of radium in seawater and river water.

[24] After returning from a summer visit to Los Altos, California, Rona received a vague telegram from the Institute of Optics at the University of Rochester referencing war work and polonium, but no details of an assignment.

[22] When Rona responded that she would be interested in helping with the war effort but had immigration issues, Brian O'Brien appeared in her office and explained the nature of the confidential work for the Manhattan Project.

[25] Plutonium plants, based on her specifications for what was needed to process element, were built in the New Mexico desert at Los Alamos National Laboratory, but Rona was given no details.

[28] Gleditsch had also warned her of the dangers the year Rona was sick and living in Paris, when Joliot-Curie died, emphasizing the risk of radium-related anemia.