Praseodymium

Because of its relatively short half-life (19.12 h) and decay primarily by beta decay (96.3 percent beta decay and 3.7 percent alpha decay), ¹⁴²Pr has been proposed for two main innovative applications in medicine, namely in microsphere brachytherapy and in eye plaque brachytherapy [425]. ¹⁴²Pr is advantageous because penetration of the beta fraction of the radiation is limited to a few millimeters in tissue, therefore limiting the dose of radiation to the treated site. ¹⁴²Pr may be produced either by fast neutron activation or thermal neutron activation of stable ¹⁴¹Pr. Research in metal-bearing radiopharmaceuticals is being conducted to determine the most efficient way to produce and process radioactive metals for in vivo tracing. This research has led to the development of a potential radionuclide generator that administers radioactive metal complexes to be observed during positron emission tomography (PET) imaging. A n(¹⁴⁰Nd)/n(¹⁴⁰Pr) amount-ratio radionuclide generator has been designed to administer ¹⁴⁰Pr complexes, such as ¹⁴⁰Pr-DTPA, to be used as a tracer during a PET scan [426]. The half-life of ¹⁴⁰Pr is 3.4 min. The n(¹⁴⁰Nd)/n(¹⁴⁰Pr) ratio radionuclide generators can also be used for administering ¹⁴⁰Pr-phosphonate complexes to identify the development of skeletal metastases. Once the skeletal metastases are found, ¹⁵³Sm-EDTMP can be administered as a radiotherapeutic agent to treat bone cancer (Fig. IUPAC.59.1) [426]. The half-life of ¹⁵³Sm is 1.9 days.