Does anyone know of any commercially available (gallium oxide) targets for producing Ge-68 on a cyclotron? Preferably but not necessarily something that is compatible with a GE PET-Trace cyclotron?
Gallium(III)-oxide (99.99%) can be purchased from Sigma-Aldrich Co., Germany, and
Gallium oxide (99.99%) Koch Chemicals Ltd. Heartfords, Hearts, England
Hi Mushtaq,
Thanks, but we actually already have a supply of the gallium oxide, it is the cyclotron targetry component that we are having difficulty sourcing.
A.
F. Roesch and D.V. Filosofov have discussed about the nuclear reactions and targetry for production of Ge-68 in IAEA report on PRODUCTION OF LONG LIVED PARENT RADIONUCLIDES FOR GENERATORS: 68Ge, 82Sr, 90Sr AND 188W., IAEA RADIOISOTOPES AND RADIOPHARMACEUTICALS SERIES No. 2, IAEA, Vienna 2010
Germanium-68 can be produced via a variety of nuclear reaction pathways. The most effective route appears to be proton irradiation of Ga targets. The high cross-section values of the (p,2n) reaction allow irradiation of natural Ga without isotopic enrichment in 69Ga at medium proton energies of between 20 and 30 MeV. In addition, if protons of higher energies are available, the (p,4n) process on 71Ga contributes to production yields. High beam intensities in the range of 100 μA or more are required to produce batch activities of >37 GBq of 68Ge. As the number of accelerators with the above features is limited worldwide, the number of 68Ge production sites is also limited. The nuclear centres at LANL (USA), BNL (USA), Cyclotron Corp Obninsk Russia and Faure (South Africa) report successful production. Attempts to establish 68Ge production have recently been reported by a few other centres. Chemical aspects of production relate to target preparation and radiochemical separation of 68Ge. Metallic Ga encapsulated in Nb containments and Ga4Ni alloys are the best choices for target materials. Chemical separation is achieved even for the separation of 68Ge from up to 100 g of Ga target materials.
The radiochemical technique that is currently preferred consists of liquid–liquid extraction of 68Ge from the dissolved target using CCl4. Following backextraction into water, high separation factors of about 106 are achieved. Specific activities obtained reach values of >74 GBq (>2 Ci) of 68Ge/mg. Radionuclidic purity is high owing to the physical decay of the co-produced short lived radionuclides (such as 67Ga and 69Ge) and radiochemical separation of the long lived radionuclides, mainly co-produced within the non-Ga target or target backing materials. Radionuclidic purity of >99.9% is achieved.
iThemba Laboratories (South Africa), Brookhaven and Los Alamos Laboratories (USA) and Cyclotron Co Ltd (Obninsk, Russia) may be contacted for supply of Ga targets, but I think such targets can be made in a small workshop.
Details about targetry can be read in attached report.
it seems to me that the proton energy and available beam intensity will be quite low (16.5 MeV 100µA or so) and especially beam power onto a oxide-powder target. Are you looking at pressing pellets onto a coin type target and drop it in a holder for irradiation ? you will then have to find suitable front cooling of target and foil (helium) and back cooling with water - but this will anyway be suitable for limited beam power. What is the final goal (activity of Ge) and suitable beam time available on your machine ?
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