Ion induced nuclear reactions
Projects and Aims
Regularly Produced, Metallic Radionuclides for Cancer Research and Theranostic Application
Copper-64 and Mercury-197(m)
Copper-64 is produced weekly by proton irradiation of enriched nickel-64 via the 64Ni(p,n)64Cu nuclear reaction[3]. Mercury-197(m) is produced bimonthly, or monthly by proton irradiation of gold via the 197Au(p,n)197(m)Hg reaction [1]. In collaboration with colleagues from the Nuclear Physics Insitute of the CAS, Řež (Czech Republic), Hg-197(m) is also produced by deuteron irradiation of gold via the 197Au(d,2n)197(m)Hg reaction. Under certain conditions, both radionuclides can be produced simultaneously, i.e. irradiating a single target with both gold and the deposited, enriched nickel. There are important challenges for producing copper-64 and mercury-197(m) that must be kept in mind. There is a lot of naturally occurring copper making the production of copper-64 with high specific activity very difficult. Devices and chemicals must be prepared or purchased as “copper free”. Additionally, the very expensive target material, enriched Ni-64, must be efficiently recycled for repeated use and electrolytic deposition to reduce production costs. In the case of mercury-197(m), high specific activity is easier to achieve due to the significantly lower abundance of mercury in devices and chemicals. This is critical for mercury to enable its use in concentrations well below the known toxicity limits. Gold is naturally enriched and as starting material is comparatively cheap and does not have to be recycled for reuse. The relatively lower yield of the nuclear reaction, however, places high demands on both efficiency in radionuclide production / separation as well as on the subsequent radiolabeling reactions. The high volatility and the generally low water solubility of organic Hg compounds are also different to other metallic radiunuclides. Furthermore, the presence of two nuclear isomers with different properties makes the simple activity determination by "activimeter" difficult. If all problems are successfully solved, mercury-197 (m) is a very promising radionuclide for theranostic use. Both radionuclides exhibit characteristic gamma ray(s) and particle emission(s) useful for imaging and therapy (links to the NUDAT data base: Cu-64 und Hg-197(m)). |
Ni-Target (links) und Au-Target (rechts) Comparison of the dose range of Cu-64 and Cu-67 in water [5] Dose distribution of both nuclear isomers Hg-197 and Hg-197m in mixture and separate and compared to the well-known therapeutically-used weak beta emitter Lu-177 and the SPECT isotope In-111 [6] |
Further Imaging Radionuclides in Research Copper-61 and Zirkonium-89 [2,4]
Copper-61, as short-lived positron emitter (t1/2 = 3.3 h), is an alternative copper isotope to Copper-64. It is very suitable for the imaging of fast biological processes (similar to fluorine-18). The respective radionuclides are produced according to the following nuclear reactions: 64Zn(p,α)61Cu-61 and 89Y(p,n)89Zr.
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References [1] M. Walther, S. Preusche, S. Bartel, G. Wunderlich, R. Freudenberg, J. Steinbach, H.-J. Pietzsch. Appl. Radiat. Isot. 2015, 97, 177 [2] S. Thieme, M. Walther, S. Preusche, J. Rajander, H.-J. Pietzsch, J.-O. Lill, M. Kaden, O. Solin, J. Steinbach. Appl. Radiat. Isot. 2013, 72, 169 [3] S. Thieme, M. Walther, H.-J. Pietzsch, J. Henniger, S. Preusche, P. Mäding, J. Steinbach. Appl. Radiat. Isot. 2012, 70, 602 [4] M. Walther, P. Gebhardt, P. Grosse-Gehling, L. Würbach, I. Irmler, S. Preusche, M. Khalid, T. Opfermann, T. Kamradt, J. Steinbach, H.-P. Saluz. Appl. Radiat. Isot. 2011, 69, 852 [5] Internal report of T. Kormoll, AG Strahlungsphysik, Institut für Kern- und Teilchenphysik, TU Dresden [6] Calculation and graphic of R. Freudenberg, Klinik und Poliklinik für Nuklearmedizin, Universitätsklinikum Carl Gustav Carus an der TU Dresden |