Radium-223  (223Ra, Ra-223) is an isotope of radium with an 11.4-day half-life. It was discovered in 1905 by T. Godlewski, a Polish chemist from Kraków, and was historically known as actinium X (AcX). Radium-223 dichloride is an alpha particle-emitting radiotherapy drug that mimics calcium and forms complexes with hydroxyapatite at areas of increased bone turnover. The principal use of radium-223, as a radiopharmaceutical to treat metastatic cancers in bone, takes advantage of its chemical similarity to calcium, and the short range of the alpha radiation it emits. Origin and preparation
Although radium-223 is naturally formed in trace amounts by the decay of uranium-235, it is generally made artificially, by exposing natural radium-226 to neutrons to produce radium-227, which decays with a 42-minute half-life to actinium-227. Actinium-227 (half-life 21.8 years) in turn decays via thorium-227 (half-life 18.7 days) to radium-223. This decay path makes it convenient to prepare radium-223 by "milking" it from an actinium-227 containing generator or "cow", similar to the moly cows widely used to prepare the medically important isotope technetium-99m.223Ra itself decays to 219Rn (half-life 3.96 s), a short-lived gaseous radon isotope, by emitting an alpha particle of 5.979 MeV.
The gene was patented by Charles D. Boyd, Katalin Csiszar, Olivier LeSaux, Zsolt Urban, Sharon Terry, and assigned to PXE International by these co-inventors. Between the filing and 2013, when the Supreme Court of the United States declared that genes may not be patented. PXE International freely licensed the gene to any lab for clinical testing and research. PXE International continues to hold and maintain other patents (diagnosis and treatment patents).PXE International, a support organization, was founded in 1995, by Patrick and Sharon Terry, following the diagnosis of their two children. It has a registry of 4,600 affected individuals. Images
See also
List of cutaneous conditions

References
External links
PXE international
pxe at NIH/UW GeneTests
Pseudoxanthoma elasticum at NLM Genetics Home Reference