| Title | Proton-induced production and radiochemical isolation of (44)Ti from scandium metal targets for (44)Ti/(44)Sc generator development. |
|---|---|
| Authors | Radchenko, V.; Engle, J.W.; Medvedev, D.G.; Maassen, J.M.; Naranjo, C.M.; Unc, G.A.; Meyer, C.A.L.; Mastren, T.; Brugh, M.; Mausner, L.; Cutler, C.S.; Birnbaum, E.R.; John, K.D.; Nortier, M.; Fassbender, M.E. |
| Journal | Nucl Med Biol |
| DOI | 10.1016/j.nucmedbio.2017.03.006 |
| Abstract |
Scandium-44g (half-life 3.97h) shows promise for application in positron emission tomography (PET), due to favorable decay parameters. One of the sources of (44g)Sc is the (44)Ti/(44g)Sc generator, which can conveniently provide this radioisotope on a daily basis at a diagnostic facility. Titanium-44 (half-life 60.0 a), in turn, can be obtained via proton irradiation of scandium metal targets. A substantial (44)Ti product batch, however, requires high beam currents, long irradiation times and an elaborate chemical procedure for (44)Ti isolation and purification. This study describes the production of a combined 175MBq (4.7mCi) batch yield of (44)Ti in week long proton irradiations at the Los Alamos Isotope Production Facility (LANL-IPF) and the Brookhaven Linac Isotope Producer (BNL-BLIP). A two-step ion exchange chromatography based chemical separation method is introduced: first, a coarse separation of (44)Ti via anion exchange sorption in concentrated HCl results in a (44)Tc/Sc separation factor of 10(2)-10(3). A second, cation exchange based step in HCl media is then applied for (44)Ti fine purification from residual Sc mass. In summary, this method yields a 90-97% (44)Ti recovery with an overall Ti/Sc separation factor of ≥10(6). |
See more Scandium products. Scandium (atomic symbol: Sc, atomic number: 21) is a Block D, Group 3, Period 4 element with an atomic weight of 44.955912. The number of electrons in each of Scandium's shells is [2, 8, 9, 2] and its electron configuration is [Ar] 3d1 4s2. 
The scandium atom has a radius of 162 pm and a Van der Waals radius of 216 pm.Scandium was predicted by Dmitri Mendeleev in 1871 and actually discovered and isolated by Lars Nilson in 1879. One of the transition metals, scandium has a silvery-white appearance in its elemental form which oxidizes to yellow or pinkish upon contact with air. 
It is occasionally included in the classification of the rare earth elements. Scandium is found in concentrated amounts in the minerals euxenite, gadolinite and thortveitite however, due to the difficulties in the preparation of metallic scandium, global trade of the pure metal is very limited. The origin of the name scandium comes from the Latin word 'scandia' meaning Scandinavia.