In spite of decades of radioactivity measurements, there are still many reference data needed to complete the decay schemes of the most important nuclides. This is why recently, the JRC has accurately measured the half-lives of actinium-225 and five of its daughter nuclides. Besides being a potential health risk, these radionuclides also have a useful side that additionally justifies studying their characteristics. The actinium-225 decay series has documented applications in nuclear medicine and oceanographic studies.
Read more in G. Suliman et al.: "Half-lives of 221Fr, 217At, 213Bi, 213Po and 209Pb from the 225Ac decay series", App. Rad. Isot. 77, 32-37 (2013)