Chemical properties
Scandium is a rare earth element, normally present in solution in oxidation state III with ionic radius of 74.5 pm. Sc-43 can be radiolabelled with macrocyclic chelators, e.g., DOTA, or with other chelators such as NODAGA, AAZTA, H4pypa, H3mpatcn, etc.
Nuclear properties
Sc-43 decays by β+ decay (88.1(8)%) or electron capture (11.9(8)%) with a half-life of 3.891(12) hours to stable Ca-43. It emits a medium-energy positron spectrum with an average energy of 476 keV and a maximum energy of 1199 keV.
Moreover, Sc-43 emits a γ-ray at 372.9 keV (22.5%).
The mean electron energy emitted per decay is 419 keV, the mean photon energy per decay is 981 keV REF.
Sc-43 and Sc-44 have very close half-lives and similar positron intensities. However, Sc-43 is lacking the intense hard γ-ray emission of Sc-44. This makes Sc-43 a more favorable alternative to Sc-44, except for specific applications where the prompt 1157 keV γ-ray in the Sc-44 decay is used. In particular, the recovery coefficient in PET imaging is higher for Sc-43 REF, and the γ dose rate is about half that.
Production
Sc-43 is produced by alpha irradiation of Ca-40 oxide targets at Rigshospitalet (Copenhagen, Denmark).
Distribution
Radiochemical separation will be performed at Hevesy Laboratory (DTU, Risø, Denmark). Sc-43 will be shipped from DTU to the users in the form of ScCl3 in HCl solution, ready for labelling i.e. with DOTA-compounds.
Examples of use
The PET imaging performance of the Sc-43/Sc-44 mixture has been compared to pure Sc-44, Ga-68 and F-18 with a phantom in a commercial PET/CT scanner REF
| Parameter | Specifications |
|---|---|
| Production route | Ca-40(α,p)Sc-43 |
| Decay | Decays to stable Ca-43: 88% β+, 12% EC |
| Half-life | 3.89 h |
| Processing | Precipitation and ion exchange chromatography |
| Primary Container | 2.5 mL borosilicate glass V-vial with silicone rubber screw cap |
| Product Grade | n.c.a. |
| Physical Form | Liquid |
| Chemical form | In dilute HCl |
| Radioactive Concentration (gamma spectrometry) | n.a. |
| Appearance | Clear colourless solution |
| Radionuclide Identification (gamma spectrometry) | 373 keV gamma line present |
| Radionuclidic purity (gamma spectrometry) | 95% |
| Chemical purity (ICP-OES) | n.a. |
| Molar activity (ICP-OES) | t.b.d. |
| Apparent Molar Activity | t.b.d. |
| Microbiological quality | n.a. |
| Bacterial endotoxin | n.a. |
| pH (pH strips) | Depends on chemical form |
| Additional information | |
| Activity available | t.b.d. |
| Activity limit for UN2910 (excepted package) shipment | 20 MBq in dry state or 2 MBq in liquid form |
| Other information |
