Er-165 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-165 too, in particular DOTA.
Er-165 decays by electron capture decay with a half-life of 10.36 hours to stable Ho-165.
Er-165 emits no γ-rays, but X-rays, notably Kα at ≈47 keV (59.4(9) %) and Kβ at ≈54 keV (14.3(19) %). These energies make Er-165 suitable for SPECT-imaging.
The mean photon energy per decay is 37 keV and the mean electron energy emitted per decay is 5 keV . Most electrons are short-range Auger electrons with <1 µm and <26 µm respectively. Er-165 has therefore been proposed as therapeutic Auger electron emitter .
Er-165 is produced by proton irradiation of natural Ho carbonate targets at Hevesy Laboratory at DTU. A Ho/Er separation is performed by ion exchange chromatography.
Activity will be shipped from the Hevesy Laboratory (DTU, Risø, Denmark) to the users in form of Er3+ solution.
|Daughter||Decays to stable Ho-165: 100% EC|
|Processing||Multi-step ion exchange|
|Primary Container||2.5 mL borosilicate glass V-vial with silicon rubber screw cap|
|Chemical Form||Er3+ ion in 0.1 M HCl solution (1-2 ml)|
|Radioactive Concentration (gamma spectrometry)||Up to 1 GBq/ml|
|Appearance||Clear colourless solution|
|Radionuclide identification (gamma spectrometry)||Metal impurities determined by ICP-OES for each batch|
|Radionuclidic Purity (gamma spectrometry)||t.b.d.|
|Chemical purity (ICP-OES)||t.b.d.|
|Molar activity (ICP-OES)||t.b.d.|
|Apparent Molar Activity||t.b.d.|
|Microbiological quality||Bioburden and endotoxin burden can be analysed post release, upon request|
|Bacterial endotoxin||Bioburden and endotoxin burden can be analysed post release, upon request|
|pH (pH strips)||t.b.d.|
|Activity available||1 GBq (more to be discussed) upon request|
|Activity limit for UN2910 (excepted package) shipment||20 MBq in dry state or 2 MBq in liquid form|