Analytické metody na katedře jaderné chemie FJFI ČVUT

summary:The article briefly introduces the Department of Nuclear Chemistry and describes the main principles of modern analytical methods which are regularly used in both the department’s research and education

Production of the positron-emitting radionuclide 68Ga: the radiochemical scheme of radionuclide generator 68Ge → 68Ga

68Ga (T1/2 = 68 min) in complexes with peptides is used in positron emission tomography for diagnostics of neuroendocrine tumors. The most promising strategy for 68Ga production is usage of the radionuclide generator 68Ge → 68Ga. In this research, the sorption behavior of Ge(IV) and Ga (III) has been studied. The distribution coefficients (Kd) of Ge(IV) on the anion exchange (Dowex 1×8) and cation exchange (Dowex 50×8) resins in various ethanedioic and hydrochloric acid solutions were determined. For each ion exchange resin, four series of measurements were carried out, in which the concentration of oxalic acid was fixed (0.001 M, 0.003 M, 0.005 M, 0.01 M), and the concentrations of hydrochloric acid ranged from 0 to 3 M. Based on the distribution coefficients, the chemical scheme of the radionuclide generator 68Ge → 68Ga has been developed. The chemical system is based on the anion exchange resin Dowex 1×8 and mixture of 0.005 M C2H2O4 / 0.33 M HCl. Several types of the generators with direct and reverse mode of elution were tested and the optimal scheme was determined. Elution of the generators was performed once a day with 8 ml of 0.005 M C2H2O4 / 0.33 M HCl solution. The 68Ga yield and the 68Ge breakthrough are comparable for all the systems

A Novel Method for 67Cu Production

Copper-67 is one of the important therapeutic radionuclides. It is a ß- emitter with half-live of 61.9 h. In addition it emits main 91, 93 and 185 keV ¿ peaks and is therefore also suitable for SPECT imaging. Recently it was shown that 67Cu has superior therapeutic effects over 64Cu, 125I and 131I and is a radionuclide of preference for targeted radio-immunotherapy. The main limitation factor however is still the lack in the Copper-67 supply. We report a novel method of production of 67Cu by deuteron irradiation of enriched 70Zn target, where the 70Zn(d,an)67Cu reaction takes place. The calculated maximum of the excitation function is reached at about 20 MeV and overall usable deuteron energy region lies between 10 and 30 MeV. The thick target yield at deuteron energy of 20 MeV is estimated to 2.6 MBq/µAh (70 µCi/µAh) and a saturation yield to 235 MBq/µA (6.35 mCi/µA) at EOB. Typical irradiation (12 h, 25 µA) should produce some 740 MBq (20mCi) of 67Cu. High specific activity 67Cu can be therefore produced in relevant quantities by this method.JRC.DG.I.5-Nanobioscience

Update on 67Cu half-life

The half-life of 67Cu was newly determined by measurement of its 185 keV γ-ray (48.7 %) over the period of 13 days (approx. 5 × T½). 67Cu was prepared by deuteron irradiation of enriched 70Zn targets. The 67Cu half-life value which resulted from five independent measurements is estimated to be 61.81 (22) h.JRC.I.5-Nanobioscience

Preparation of 67Cu via deuteron irradiation of 70Zn

A method for preparation of n.c.a. 67Cu based on deuteron irradiation of enriched 70Zn is presented. Cross-sections for 67Cu formation were determined by the stacked foil technique for deuteron energies in the range from 10 to 20 MeV for the first time. Irradiations of 70Zn foils were followed by radiochemical separation of 67Cu from the target material and co-produced radionuclidic impurities. The maximum cross-section value of 25.5 ± 2.2 mb was reached at 19 MeV. The integral yield in the energy window of 20 → 10 MeV on 95 % enriched 70Zn is estimated at 4.2 MBq/μAh (110 μCi/μAh) or 375 MBq/μA (10 mCi/μA) at saturation.JRC.I.4-Nanobioscience

Simultaneous Experimental Determination of Energy and Intensity of Cyclotron Beams in the Energy Range Below 40 MeV

An experimental method for simultaneous determination of energy and intensity of a charged particle beam is presented and results obtained with proton, 3He2+ and a particle beams in the energy range below 40 MeV are reported. The method is based on activity measurements of at least two radioisotopes produced simultaneously in a thin target sample. The beam energy is deduced from the activity ratio of the two radioisotopes while the intensity may then be calculated from the activity of one of the two considered radioisotopes. The target materials used in this work are those for which recommended excitation functions for the radioisotopes are available from the IAEA data base. Copper foils were irradiated with protons and a particles while aluminium foils were used for irradiation with 3He2+ particles. The range of beam energies investigated in this work are those available at the Scanditronix MC 40 (K=40) cyclotron for which the maximum energy for both protons and a particles is 40 MeV, while for 3He2+ particles it is 53 MeV. With respect to the nominal settings of the cyclotron, the results obtained are very satisfactory; being in agreement within 1%, 5% and 7% for beams of protons, a and 3He2+ particles respectively. The method is easy to apply, economic and also relatively accurate and precise, provided that the cross sections of the considered nuclear reactions are available. It can be applied for various energy ranges of charged particle beams from cyclotrons or linear accelerators, and is especially useful for determination of beam energy and intensity after transmission through material with inaccurately known characteristics and properties such as powders or porous matter, or after transmission through complex target systems.JRC.DG.I.5-Nanobioscience