Production of Cu-64

In the last years there has been a growing interest in the use of radiopharmaceuticals labelled with metallic radionuclides.

Particularly, Cu-64 with an intermediate half-life of 12.7 hours, is expected to be a promising combined radiotracer for positron emission tomography (PET) and radiotherapy, since Cu-64 decays by emitting both β- and β+ particles.

A new production method of Cu-64 has recently been established at the Hevesy Laboratory. Presently, the isotope is used for the labelling of different radiopharmaceuticals that are used in human and animal studies in collaboration with Rigshospitalet-Copenhagen University Hospital and the Panum Insititute in Copenhagen. Cu-64 is also used at the Hevesy Laboratory for other related research experiments.

The routine production of Cu-64 is performed at the cyclotron and beamline facility at the Hevesy Laboratory. The isotope is produced in a (p,n) reaction by irradiating a solid enriched (99%) Ni-64 metal target with a 16 MeV proton beam. After the irradiation (duration 3 to 4 hours) the target is transferred to the laboratory for further processing. Chemical separation ensures that carrier-free Cu-64 is separated from the Ni-64 target material. A typical yield of Cu-64 after separation is 1.5 GBq.

An ongoing project is aiming at producing Cu-64 on a high-activity scale (5 – 10 GBq after chemical separation). For this purpose a so-called High Power Target that resists proton beam currents up to 200 µA has been developed. Such a high proton current reduces the irradiation time drastically and an activity of 10GBq of Cu-64 is easily reached within a few minutes of irradiation time.

These high activity levels of Cu-64 are difficult to handle safely in the laboratory without exposing the staff to a too high radiation dose. The present project therefore also includes the set up of an automation facility for the chemical separation process.