Theoretical estimation of 64 Cu production with neutrons emitted during 18 F production with a 30MeV medical cyclotron.

PURPOSE: This work presents the theoretical estimation of a combined production of18 F and64 Cu isotopes for PET applications.64 Cu production is induced in a secondary target by neutrons emitted during a routine18 F production with a 30MeV cyclotron: protons are used to produce18 F by means of the18 O(p,n)18 F reaction on a [18 O]-H2 O target (primary target) and the emitted neutrons are used to produce64 Cu by means of the64 Zn(n,p)64 Cu reaction on enriched zinc target (secondary target).

METHODS: Monte Carlo simulations were carried out using Monte Carlo N Particle eXtended (MCNPX) code to evaluate flux and energy spectra of neutrons produced in the primary (Be+[18 O]-H2 O) target by protons and the attenuation of neutron flux in the secondary target.64 Cu yield was estimated using an analytical approach based on both TENDL-2015 data library and experimental data selected from EXFOR database.

RESULTS: Theoretical evaluations indicate that about 3.8 MBq/μA of64 Cu can be obtained as a secondary, 'side' production with a 30MeV cyclotron, for 2h of irradiation of a proper designed zinc target. Irradiating for 2h with a proton current of 120 μA, a yield of about 457 MBq is expected. Moreover, the most relevant contaminants result to be63,65 Zn, which can be chemically separated from64 Cu contrarily to what happens with proton irradiation of an enriched64 Ni target, which provides64 Cu mixed to other copper isotopes as contaminants.

CONCLUSIONS: The theoretical study discussed in this paper evaluates the potential of the combined production of18 F and64 Cu for medical purposes, irradiating a properly designed target with 30MeV protons. Interesting yields of64 Cu are obtainable and the estimation of contaminants in the irradiated zinc target is discussed.