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

Purpose: This work presents the theoretical estimation of a combined production of 18 F and 64 Cu isotopes for PET applications. 64 Cu production is induced in a secondary target by neutrons emitted during a routine 18 F production with a 30 MeV cyclotron: protons are used to produce 18 F by means of the 18 O(p,n) 18 F reaction on a [ 18 O]-H 2 O target (primary target) and the emitted neutrons are used to produce 64 Cu by means of the 64Zn(n,p) 64Cu 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]-H 2 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 of 64 Cu can be obtained as a secondary, ‘side’ production with a 30 MeV cyclotron, for 2 h of irradiation of a proper designed zinc target. Irradiating for 2 h with a proton current of 120 μA, a yield of about 457 MBq is expected. Moreover, the most relevant contaminants result to be 63,65 Zn, which can be chemically separated from 64 Cu contrarily to what happens with proton irradiation of an enriched 64 Ni target, which provides 64 Cu mixed to other copper isotopes as contaminants. Conclusions: The theoretical study discussed in this paper evaluates the potential of the combined production of 18F and 64Cu for medical purposes, irradiating a properly designed target with 30 MeV protons. Interesting yields of 64 Cu are obtainable and the estimation of contaminants in the irradiated zinc target is discussed.