Friday, July 11, 2008

Georg Charles von Hevesy

Recently I finished reading the biography Niels Bohr's Times,: In Physics, Philosophy, and Polity, by Abraham Pais. It is an excellent book, but not quite as good as Pais's masterpiece, Subtle Is the Lord: The Science and the Life of Albert Einstein. Although I was familiar with Bohr's research in atomic and nuclear physics, I was surprised to discover his pioneering role (perhaps more as a fund raiser, administrator, and mentor than researcher) in medical and biological physics.

Much of this research was in collaboration with Georg Charles von Hevesy (1885-1966). Pais writes "The work of Hevesy in the 1930s at Bohr's institute made isotope tracers methods flourish. And so Bohr became the godfather, and Hevesy the father, of nuclear medicine." Hevesy was a Hungarian of Jewish descent who was a professor in Germany in the 1930's until "he left Freiburg because of his disgust with the Nazi regime." In 1934 he joined Bohr in Copenhagen. Hevesy began using heavy radioactive isotopes to study the uptake and loss of elements. In Pais's words, Hevesy made

"the first application anywhere of tracers in the life sciences....This led Hevesy to tracer research...on the resorption, distribution, and excretion of labeled bismuth compounds administered to rats, the first use of tracers in the study of animal metabolism...

In 1948 Hevesy wrote: 'During our early work with natural radioisotopes as indicators, we often mentioned what an attractive place that Fairyland must be where radioactive isotopes of all elements are available. This utopia became reality almost in a single stroke, when the Joliot-Curies made their most important discovery of artificial radioactivity [man-made radioactive isotopes]. The path was thus paved for investigation of the fate of the atoms of the common constituents of the animal and plant organisms.'...

Hevesy was 50 years old in 1935 when he turned his attention to applications of induced radioactivity. That year marks the beginning of the most important phase in his scientific career. [An inspiring thought to this 47-year-old writer.] From then on he very rarely published anything in physics; nearly all his further oeuvre, over 200 papers, deal with tracers in biology. That work was more influential than anything he had done before...

Hevesy certainly added to the life in Copenhagen. There is the story of the radioactive cat that had jumped out of a window of the institute for theoretical physics and was retrieved only after hours of hunting for it in the nearby park, when saliva tests on about a dozen captured cats showed one of them to be radioactive...

In 1944 Hevesy was awarded the 1943 Nobel Prize in chemistry 'for his work on the use of isotopes as tracers in the study of chemical processes'...

In the post-war period the development of nuclear reactors provided for vastly enlarged production of radioisotopes. This in turn made possible much wider application of the tracer method in medicine. In hospitals all over the world one now finds special departments for nuclear medicine, a discipline which unquestionably was founded by Hevesy. Also from that period dates the use of numerous biological tracers with half-lives much longer that that of the popular P-32, notably the carbon isotope C-14 discovered in 1940."

Chapter 17 of the 4th Edition of Intermediate Physics for Medicine and Biology discusses nuclear medicine, and the work of those "special departments for nuclear medicine." Pais's excellent biography makes clear that these important medical applications arose from the pioneering work of Neils Bohr and Georg Charles von Hevesy. Next week: the story continues, with more on Neils Bohr's impact on biological physics.

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