Chemical properties

In solution Cu-67 is usually in divalent state. It can be radiolabelled with macrocyclic chelators. DOTA is being used, but other, specific copper chelators such as MeCOSar may provide improved stability.

Nuclear properties

Cu-67 decays by β^- decay with a half-life of 2.576(5) days to stable Zn-67. It emits a low energy β^- spectrum with 145 keV average energy and 561 keV maximum energy based on branching ratios measured by Chen et al. . In addition to β^- emission it also emits low energy conversion and Auger electrons , thus emitting in total about 1.2 electrons (with energies above 7 keV) per decay.

Moreover, Cu-67 emits γ-rays at 184.6 keV (44.2%) and 91.3 / 93.3 keV (together 21.1%)  which are suitable for SPECT imaging.

The mean electron energy emitted per decay is 148 keV, the mean photon energy per decay is 101 keV .

Production

Cu-67 is produced by proton irradiation of enriched Zn-70 targets at Hevesy Lab, DTU, Denmark.

Cu-67 is produced by deuteron irradiation of enriched Zn-70 targets at the cyclotron ARRONAX, Nantes, France.

Distribution

The radiochemical separation is performed at production site and activity will be shipped from there to the users in form of CuCl₂ solution.

Examples of use

• Cu-67 forms a theranostic pair together with Cu-64.
• Medium energy collimators are recommended for SPECT imaging with Cu-67 .
• Clinical trials with Cu-67-radioimmunotherapy have been performed in the past.
• Clinical trials with Cu-67-peptide receptor radionuclide therapy and Cu-67-PSMA radioligand therapy are ongoing.