If the half-life of lead is 28 days, how long will it take...
A patient is given 0.050 mg of technetium-99m, a radioactive isotope with a half-life of about 6.0 hours. How long does it take for the radioactive isotope to decay to 1.0 x 10-3 mg? (Assume the nuclide is not excreted from the body.) ...