Table 1.
Current commercially available radiometals (FDA approved or under development), their most suitable chelators according to recent literature, most commonly used radiolabelling conditions, thermodynamic stability, acid stability and redox properties.a
| Radiometal, modality (Most common oxidation state) | Chelatorb | Radiolabelling conditions required for > 95 % radiochemical yield | Approved or stage of development |
|---|---|---|---|
| Ga-68, PET, (III) Ga-67, SPECT |
NOTA, DOTA |
37 °C, 30 min, pH 7.5 100 °C, 20 min, pH 5.5 |
NetSpot® Gallium-citrate |
| Cu-64, PET (II) Cu-67, β− |
NOTA, CB-TE2A |
25 °C, 30–60 min, pH 5.5 95 °C, 60 min, pH 5–6 |
Cu-ATSM (Phase II) Cu-DOTATATE (Phase III) |
| Zr-89, PET, (IV) | DFO | 25 °C, 60 min, pH 7.5–8 | 89Zr-trastuzumab (Phase II) |
| Tc-99m (V) Tc-99m (I), SPECT |
MAG3, M(CO)3(H2O)3 (fac-isomer) |
25 °C, 60 min, SnCl2, C7H13NaO8 100 °C, 30 min, K2(H3BCO2) |
99mTc MAG3 MIP-1404 (Phase II/III) |
| In-111, SPECT, (III) |
DOTA CHX-A”DTPA |
65–90 °C, 30–40 min, pH 5.5 25–40 °C, 10–40 min, pH 5.5 |
ProstaScint® |
| Y-90, β− (III) | DOTA CHX-A”DTPA |
25–100 °C, 15 min, pH 5 25°C, 30 min, pH 5.5 |
Zevalin® Therasphere® |
| Lu-177, β− (III) | DOTA | 25–90 °C, 30 min, pH 4.5 | Lutathera® |
a
The radiometals highlighted here represent only a small subset of radiometals which have increasing interest and relevance in the field.
b
See Figure 2 for their structures.