In solution Cu-64 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 .
Cu-64 decays with a half-life of 12.70 h by β+ decay (17.6%) or electron capture (43.9%) to stable Ni-64 and by β- emission (38.5%) to stable Zn-64 respectively. The emitted positrons have 278 keV average energy and 653 keV maximum energy and the emitted low energy β- spectrum has 191 keV average energy and 579 keV maximum energy.
In addition to β- emission it also emits low energy Auger electrons , thus emitting in total about 0.79 electrons or positrons (with energies above 6 keV) per decay.
Cu-64 emits only one weak γ-ray at 1345.8 keV (0.48%).
The total electron energy emitted per decay is 124 keV, the total photon energy per decay is 187 keV .
Cu-64 can be produced by different methods , e.g. proton irradiation of enriched Ni-64 targets at Hevesy Laboratory at DTU, C30 cyclotron at NCBJ and Injector 2 at PSI or deuteron irradiation of enriched Ni-64 targets at ARRONAX. In addition, low-specific activity (>0.1 GBq/mg) Cu-64 is produced at NCBJ by irradiating enriched Cu-63 targets in the MARIA reactor.
The radiochemical separation is performed at the same laboratory where the irradiation took place. Activity will be shipped from there to the users in solution or in form of a dried deposit respectively.
The specifications given here are the ones for production at Hevesy Laboratory (DTU, Risø, Denmark). The characteristics of the produced Cu-64 varies for the other suppliers (ARRONAX, Nantes, France; PSI, Villigen, Switzerland; NCBJ, Otwock-Swierk, Poland), and the best solution for a given project will be discussed between PRISMAP and the users.
|Production route (cyclotron)||Ni-64(p,n)Cu-64 [or Ni-64(d,2n)Cu-64 at ARRONAX]|
|Decay||Decays to stable Ni-64 and stable Zn-64: 17.6% β+, 43.9% EC, 38.5% β-|
|Processing||One step cation exchange chromatography|
|Primary Container||2.5 mL borosilicate glass V-vial with silicon rubber screw cap|
|Chemical form||CuCl2 in dry form|
|Radioactive Concentration (gamma spectrometry)||n.a.|
|Appearance||Invisible deposit at bottom of glass vial|
|Radionuclide Identification (gamma spectrometry)||1346 keV gamma line and 511 keV annihilation gamma line present|
|Radionuclidic purity (gamma spectrometry)||>99.9% at calibration time (Co-56, Co-57, Co-58 each below 0.01%)|
|Chemical purity (ICP-OES)||Cu, Ni, Zn, Co and Fe each <1 µg per GBq Cu-64|
|Molar activity (ICP-OES)||>500 GBq/µmol at calibration time (>5% of theoretical maximum)|
|Apparent Molar Activity||>100 GBq/µmol (DOTA labelling) at calibration time|
|Bacterial endotoxin||<175/V IU/ml (V being the maximum volume to be used for the preparation of a single patient dose)|
|pH (pH strips)||n.a.|
|Activity available||1 - 10 GBq|
|Activity limit for UN2910 (excepted package) shipment||1 GBq in dry state or 0.1 GBq in liquid form|
|Other information||Product is normally shipped in dry state, in “empty vials” but ready for reconstitution with what buffer the user prefers, and then ready for labelling of e.g. DOTA-compounds. Upon request, product can be shipped in 0.05 M HCl (1-2 ml) or Ammonium Acetate buffer (1 M, 1-2 ml). Bioburden and endotoxin burden can be analysed post release, upon request|