Novel radiochemical separation of arsenic from selenium for 72Se/72As generator

Labelling with positron emitters of pnicogens and chalcogens

“…A further advantage of 72 As is the possibility of obtaining it by using a radionuclide generator where arsenic is formed by the radioactive decay of selenium‐72 ( 72 Se). The 8.4‐day half‐life of 72 Se makes the 72 Se/ 72 As pair ideal for a radioisotope generator from which 72 As can be obtained for about a month, potentially leading to portable availability of this PET radionuclide . In combination with the β − ‐emitting radionuclide arsenic‐77 ( 77 As), these 2 radioisotopes allowed their application as a “matched pair” for diagnostic and therapeutic radiopharmaceuticals, if the chemistry to incorporate them into physiologically stable molecules is developed, as first demonstrated for the yttrium‐86/yttrium‐90 pair and recently reviewed in detail …”

“…The 8.4-day half- 72 As pair ideal for a radioisotope generator from which 72 As can be obtained for about a month, potentially leading to portable availability of this PET radionuclide. 19 In combination with the β − -emitting radionuclide arsenic-77 ( 77 As), these 2 radioisotopes allowed their application as a "matched pair" for diagnostic and therapeutic radiopharmaceuticals, 16 if the chemistry to incorporate them into physiologically stable molecules is developed, as first demonstrated for the yttrium-86/yttrium-90 pair 20 and recently reviewed in detail. 21 Considering the pnictogen element antimony, only the positron emitter antimony-118 ( 118 Sb) with its half-life of 3.6 minutes has been regarded as potentially useful for PET flow studies.…”

Mapping biological behaviors by application of longer-lived positron emitting radionuclides

“…It decays with high abundance of β + emission (E max = 2.5 MeV, 88%), and is an attractive radionuclide for PET imaging. The optimal method for production and purification of 72 As via a rapid and practical generator system remains under investigation [51,52]. Presently, 72 As can be generated either from a 72 Se/ 72 As generator system or cyclotron produced from a germanium target [53].…”

Chromatographic separation of selenium and arsenic: A potential 72Se/72As generator

“…Selenium-72/Arsenic-72 ( 72 Se/ 72 As) radionuclide generators have been proposed in the literature [14], however complex separation/isolation methods are required. Separation of the daughter from the parent can occur via repeated distillation of “grown-in” 72 AsCl 3 from carrier added 72 Se stock solutions [16,21]; electroplating of 72 Se as Cu 2 Se on Cu backings [23], solvent extraction [22] or solid phase extraction of 72 Se [17,24]. However, with the exception of the solid phase extraction method, the reported methods require laborious and/or significant handling.…”

“…However, with the exception of the solid phase extraction method, the reported methods require laborious and/or significant handling. The solid phase approach as reported in the literature is limited to very small dimensions (500 μL cartridge volume, few μCi of 72 Se activity) involving reagents such as HF, requires Se in its elemental state under an inert atmosphere to prevent oxidation, and scale up to clinically useful 10 mCi batches may not be feasible [17,22,24]. …”