Molybdenum-99 decays to form “metastable” technetium-99 (⁹⁹TC) through beta decay. This isotope has a very long lifetime (half-life of 6 hours) compared to other nuclear isomers that undergo gamma decay. The gamma rays emitted when ⁹⁹Tc decays are easily detected, which makes this species ideal for a variety of medical imaging applications, such as single-photon emission computed tomography. At the beginning of this millennium, the decommissioning of two nuclear reactors created a critical shortage of ⁹⁹Tc, and this shortage remains to be addressed [Science, 331 (2011), 227]. Imagine you are performing an imaging experiment with ⁹⁹Tc where after injecting the isotope into the patient you need 2 hours to obtain the image. How much of the ⁹⁹Tc will have decayed during this time?