Even that speed might be enough to be useful for people with heart disease who need new cardiomyocytes, says Charles Murry, who studies cardiovascular medicine at the University of Washington in Seattle.
First, they use a chemical pretreatment to remove the contaminating carbon from the collagen in bones, then they measure the minuscule amounts of radiocarbon using a particle accelerator.
C, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.
After the Second World War, tests of nuclear bombs spewed carbon-14 pollution into the atmosphere.
This isotope was incorporated into plants and the people who consumed them.
Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples.