- Person
- Emilio Segrè
- Lived
- 1905–1989
- Field
- Nuclear physics
- From
- Italian-American
The story
Emilio Segrè was born in 1905 into a Sephardic Jewish family in Tivoli, near Rome, and studied physics under Enrico Fermi. In 1937, as director of the physics laboratory at the University of Palermo, he received from Ernest Lawrence in Berkeley a strip of molybdenum from a cyclotron that was giving off unusual radiation. With the mineralogist Carlo Perrier he proved that some of it came from a previously unknown element, number 43. It was the first element made artificially, and in 1947 they named it technetium.
In 1938, while Segrè was visiting Berkeley, Mussolini’s government passed racial laws barring Jews from university posts, and he could not return to Italy. Working on a low salary at Lawrence’s Radiation Laboratory, he and Glenn Seaborg isolated a metastable form of the element, technetium-99m, and showed that it decays with a half-life of about six hours and is produced from a longer-lived molybdenum isotope.
Others turned the discovery into medicine. At Brookhaven National Laboratory, Walter Tucker and Margaret Greene built the first technetium generator in 1958, and in 1960 Powell Richards proposed using technetium as a medical tracer. Production and use expanded rapidly across the world in the 1960s, helped by improvements in gamma cameras. Its properties proved ideal: it gives off gamma rays that cameras detect easily, and its short half-life keeps patients’ radiation dose low. Because it comes from molybdenum-99, which lasts several days, hospitals can draw fresh technetium from generators as needed.
Technetium-99m became the most widely used medical radioisotope in the world. It is used in roughly 85 percent of nuclear medicine imaging, for scans of the heart, bones, brain, thyroid, lungs, kidneys and tumours. Segrè later won the 1959 Nobel Prize in Physics, with Owen Chamberlain, for discovering the antiproton, but the isotope he found as a stranded refugee may be his most widely felt contribution.
Why it matters
Technetium-99m scans, used in tens of millions of procedures a year, let doctors see the heart, bones and organs without surgery to diagnose cancer, heart disease and other conditions.
About Emilio Segrè
Italian-born physicist who co-discovered technetium, the first artificial element, and with Glenn Seaborg isolated technetium-99m, used in tens of millions of medical scans a year. Nobel 1959.
Sources
- Technetium-99m Wikipedia
- Emilio Segrè Wikipedia
- Emilio Segrè, Biographical NobelPrize.org
Another act of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.