Chemical properties
Er-169 is a radiolanthanide, usually in trivalent state. The ionic radius of Er3+ is 89 pm, i.e. just 3% larger than Lu3+, which explains that chelators suitable for Lu-177 can be directly employed for Er-169 too, in particular DOTA.
Nuclear properties
Er-169 decays by β- emission with a half-life of 9.392(18) days to stable Tm-169. In addition to β- emission it shows emission of low energy conversion and Auger electrons REF, thus emitting in total about 1.45 electrons (with energies above 6 keV) per decay. However, γ-ray and X-ray emissions are very weak.
The mean electron energy emitted per decay is 103 keV, and the mean photon energy per decay is <1 keV REF.
Production
Er-169 is produced by thermal neutron bombardment of enriched Er-168 oxide targets in the high flux reactors of the production facilities: RHF at ILL or MARIA at NCBJ. Off-line mass separation from stable Er-168 is performed at the CERN-MEDICIS facility.
Distribution
Mass-separated radionuclides will be shipped from CERN-MEDICIS to the users in the form of ErCl3 solution or in solid form, implanted into NaCl, Al or Zn layer on a metallic foil.
| Parameter | Specifications |
|---|---|
| Production route | Er-168(n,γ)Er-169 |
| Daughter | Decays to stable Tm-169: 100% β- |
| Half-life | 9.39 d |
| Processing | Off-line mass separation + 2-step column separation |
| Primary Container | 2.5 mL borosilicate glass V-vial with silicon rubber screw cap, 5.0 mL borosilicate glass V-vial with silicone rubber screw cap (liquid samples) or20 mL borosilicate glass vial with Al foil screw cap (solid samples) from MEDICIS. |
| Product Grade | n.c.a. (but not in theoretical molar activity) |
| Physical Form | Solid or Liquid |
| Chemical Form | In 0.05 – 0.1 M HCl |
| Radioactive Concentration (gamma spectrometry) | n.a. |
| Appearance | Clear solution |
| Radionuclide identification (gamma spectrometry) | Presence of 110 keV gamma line |
| Radionuclidic Purity (gamma spectrometry) | >99% |
| Chemical purity (ICP-OES) | n.a. |
| Molar activity (ICP-OES) | n.a. |
| Apparent Molar Activity | Labelling at 10 MBq/nmol PSMA-617 |
| Microbiological quality | n.a. |
| Bacterial endotoxin | n.a. |
| pH (pH strips) | n.a. |
| Additional information | |
| Activity available | 100 MBq few times per year, depends on reactor and MEDICIS schedule |
| Activity limit for UN2910 (excepted package) shipment | 1 GBq in dry state or 0.1 GBq in liquid form |
| Other information | Research grade implanted in Al, Zn or NaCl layer on Au foil also possible |
