The quantitative recovery and purification of spallogenic 43K for nuclear medicine

43K is used in diagnostic nuclear medicine for body electrolyte and cardiovascular investigations. This nuclide is produced at LAMPF by the spallation of V targets with medium-energy protons, and a chemical procedure has been developed for the isolation of radiopotassium from the bulk target material and various spallogenic impurities. Approximately one hour after the irradiation, the V foil was dissolved in 8M HNO3. For separating the alkali metal radioelements from the bulk V target the inorganic exchanger hydrated antimony pentoxide (HAP) was used. While HAP was expected to quantitatively retain both K and Na in acid solution, it was discovered that V was not adsorbed under these conditions. To remove radiopotassium from the HAP, the column was then eluted with 12M HCl. The chelating ion-exchange resin Chelex-100 has been found to show little affinity for the alkali-metal elements, while retaining many complex-forming cations. This resin was therefore chosen for the final decontamination step. 43K is thus recovered with a 91 % chemical yield and is sufficiently decontaminated for radiologic applications. (T.G.)