The are several isotopes of lead that are important in nuclear medicine. 201Pb, produced by proton irradiation of isotopically enriched thallium targets, is the parent of 201Tl used in heart scans. 203Pb and 212Pb are a theranostic pair gathering interest, respectively, for the imaging and treatment of various cancers when chelated to the appropriate biolocalization agents[1].

Following dissolution of Tl targets in HNO3, 201Pb can be separated using Sr Resin and recovered in 6-8M HCl for further processing to recover the 201Tl. A similar process can be used to purify 203Pb from Tl target material. However, since the 203Pb is the desired final radionuclide, it may be recovered in a dilute buffer solution, such as 0.05M ammonium acetate. 212Pb is recovered with 1-2M HCl from a generator containing 224Ra adsorbed to a column of strong acid cation exchange resin. Prior to labeling to the biolocalization agent, 203Pb and 212Pb may undergo additional purification on a small cartridge of Pb or Sr Resin by loading in dilute HCl and recovering the Pb in dilute ammonium acetate.

In all applications of Sr or Pb resin for the production of medical radionuclides, it is important to consider not just the radionuclidic purity of the final product, but also the chemical purity. Sr and Pb resin contain a crown ether dissolved in 1-octanol and 2-decanol, respectively. A small amount of the alcohol will leach off of the resin and must be removed using a polymeric or inorganic adsorbant or some other separation technique prior to administration.


[1] Li, M., Zhang, X., Quinn, T., Lee, D., Liu, D., Kunkel, F., Zimmerman, B., McAlister, D.R., Olewein, K., Menda, Y., Mirzadeh, S., Copping, R., Johnson, F.L., Shultz, M.K., 2017. “Automated cassette-based production of high specific activity [203/212Pb]peptide-based theranostic radiopharmaceuticals for image-guided radionuclide therapy for cancer,” Applied Radiation and Isotopes, 127, 52-60.