Cyclotron production of carrier-free 66Ga as a positron emitting label of albumin colloids for clinical use

Abstract

A method for producing carrier free 66Ga (T1/2:9.4 h; beta +) by 4He bombardment of natural copper targets is presented. 66Ga is formed by means of the 63Cu (4He, n) 66Ga reaction. Production yields are given in the 17.5 to 8 MeV 4He energy range. Chemical purification of 66Ga from the copper target is described. The only radionuclidic impurity found in the final product was 67Ga. Albumin colloids from commercially available kits designed for use with 99mTc could easily be labeled with 66Ga and employed for studies of the lymphatic system by positron emission tomography.

Positron-Emitting Isotopes Produced on Biomedical Cyclotrons

“…Albumin microspheres have also been labeled with 66 Ga and studied [86]. These microspheres can be labeled directly with gallium, or through a BFC which is covalently bound to the microspheres.…”

“…The mean energy of positrons is however much lower at 0.664 MeV resulting in less image degradation than what one would expect by looking solely at the maximum energy. 86 Y can be produced on small biomedical cyclotrons via the 86 Sr(p,n) 86 Y reaction using a 86 SrCO 3 target. High purity 86 Y is needed for efficient labeling.…”

“…These microspheres can be labeled directly with gallium, or through a BFC which is covalently bound to the microspheres. The 66 Ga-labeled albumin colloids have been proposed for studying slow dynamic processes such as those associated with the lymphatic transport [86].…”

“…Two platinum electrodes are then placed in the solution and electrolytic deposition is performed for 60 min. 86 Y electrodeposits on the cathode, which is then removed from the solution with the voltage still turned on. The electrode containing 86 Y is washed with acetone and placed in a second beaker with 0.003 N HNO 3 and heated to 50°C.…”

Excitation Functions of Proton Induced Nuclear Reactions on Enriched 66Zn,67Zn and 68Zn

“…Recently ®®Ga = 9.5 h) has been proposed for studying some slow dynamic processes by PET [2], These radionuclides can be produced economically with low energy cyclotrons mainly via (p, n) reactions on isotopically enriched Zn targets. Over the years extensive studies on excitation functions of these reactions have been performed, but the use of natural zinc targets in all earlier measurements caused some difficulties on the Separation of (p,2n) process at higher energies.…”