title: Theoretical estimation of64Cu production with neutrons emitted during18F production with a 30MeV medical cyclotron.
abstract: OBJECTIVE
  This work presents the theoretical estimation of a combined production of18F and64Cu isotopes for PET applications.64Cu production is induced in a secondary target by neutrons emitted during a routine18F production with a 30MeV cyclotron: protons are used to produce18F by means of the18O(p,n)18F reaction on a [18O]-H2O target (primary target) and the emitted neutrons are used to produce64Cu by means of the64Zn(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+[18O]-H2O) target by protons and the attenuation of neutron flux in the secondary target.64Cu 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 of64Cu 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 be63,65Zn, which can be chemically separated from64Cu contrarily to what happens with proton irradiation of an enriched64Ni target, which provides64Cu mixed to other copper isotopes as contaminants.
  
  
  CONCLUSIONS
  The theoretical study discussed in this paper evaluates the potential of the combined production of18F and64Cu for medical purposes, irradiating a properly designed target with 30MeV protons. Interesting yields of64Cu are obtainable and the estimation of contaminants in the irradiated zinc target is discussed.
authors.affiliation: Nuclear Medicine Unit, University Hospital "G. Martino", Messina, Italy; INFN - Istituto Nazionale di Fisica Nucleare, Messina, Italy. Electronic address: lauditore@unime.it.
authors.forename: Lucrezia
authors.initials: L
authors.lastname: Auditore
authors.affiliation: INFN - Istituto Nazionale di Fisica Nucleare, Messina, Italy; Section of Radiological Sciences, Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Amato
authors.affiliation: Nuclear Medicine Unit, University Hospital "G. Martino", Messina, Italy; Section of Radiological Sciences, Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Baldari
keywords: Copper-64; Cyclotron; Fluride-18; Neutrons; Positron emission tomography