Application of tracer packet technique for multielemental uptake studies on the inorganic ion exchanger zirconium vanadate

Radioarsenic: A promising theragnostic candidate for nuclear medicine

Molecular imaging is a non-invasive process that enables the visualization, characterization, and quantitation of biological processes at the molecular and cellular level. With the emergence of theragnostic agents to diagnose and treat disease for personalized medicine there is a growing need for matched pairs of isotopes. Matched pairs offer the unique opportunity to obtain patient specific information from SPECT or PET diagnostic studies to quantitate in vivo function or receptor density to inform and tailor therapeutic treatment. There are several isotopes of arsenic that have emissions suitable for either or both diagnostic imaging and radiotherapy. Their half-lives are long enough to pair them with peptides and antibodies which take longer to reach maximum uptake to facilitate improved patient pharmacokinetics and dosimetry then can be obtained with shorter lived radionuclides. Arsenic-72 even offers availability from a generator that can be shipped to remote sites and thus enhances availability. Arsenic has a long history as a diagnostic agent, but until recently has suffered from limited availability, lack of suitable chelators, and concerns about toxicity have inhibited its use in nuclear medicine. However, new production methods and novel chelators are coming online and the use of radioarsenic in the pico and nanomolar scale is well below the limits associated with toxicity. This manuscript will review the production routes, separation chemistry, radiolabeling techniques and in vitro/in vivo studies of three medically relevant isotopes of arsenic (arsenic-74, arsenic-72, and arsenic-77).

Separation of 195(m,g),197mHg from bulk gold target by liquid-liquid extraction using hydrophobic ionic liquids

The 195(m,g),197mHg radionuclides were produced in accelerator when natural Au foil was irradiated with 23 MeV protons. The no-carrier-added (NCA) Hg radioisotopes were separated from the bulk Au target by liquid-liquid extraction (LLX) employing hydrophobic RTILs 1-butyl-3-methylimidazolium hexafluorophosphate([C4mim][PF6]) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide([bmim][Tf2N]) as extractant with HNO3 and HCl. In each case, bulk Au was extracted into the RTIL phase leaving NCA Hg-radionuclides in the aqueous phase. The RTILs were recovered by washing with 1 M K2S2O5 and freshly prepared 1 M FeSO4. The reported separation methods follow green chemistry approach as it does not involve any volatile reagents.

Production and separation of no-carrier-added 73 As and 75 Se from 7 Li irradiated germanium oxide target

This work reports for the first time 7Li-induced accelerator based production of 71,72,73,74As, 75,76,77Br and 73,75Se radionuclides in their no-carrier-added (nca) state. After the decay of all short-lived radionuclides 75Se and 73As were only existing radionuclides in germanium oxide target, which were subsequently separated by liquid-liquid extraction (LLX) using trioctylamine (TOA) dissolved in cyclohexane as liquid ion exchanger. The presence of stable germanium in various fractions was examined by Inductively Coupled Plasma Optical Spectrometry (ICP-OES). At 0.1 M TOA and 10 M HCl concentration, 75Se and stable Ge were extracted into the organic phase leaving 73As in the aqueous phase. The bulk Ge was stripped back to the aqueous phase by 1 M NaOH, keeping 75Se in the organic phase. Therefore complete separation between 73As, 75Se and bulk Ge was achieved.

Separation of 134Cs and 152Eu using inorganic ion exchangers, zirconium vanadate and ceric vanadate

Two inorganic ion exchangers, zirconium vanadate and ceric vanadate were synthesized and applied to confine and separate (152)Eu and (134)Cs from a synthetic mixture. The percentages of adsorption of the two radionuclides were studied for the two ion exchangers at varying pH conditions. At pH 3, zirconium vanadate adsorbs both Eu and Cs and a column chromatographic separation was achieved using 0.1M EDTA as the eluant. The ceric vanadate ion exchanger showed an increased trend in adsorption for both the radionuclides with increase of pH value from 1 to 6. At pH 1, a column chromatographic separation of these radionuclides from a mixture was achieved, because at this pH only (134)Cs was adsorbed to ceric vanadate bed in the column.