Table 1.
Microsphere characteristics
| Microsphere | TheraSphere® | SIR-Spheres® | Holmium microspheres |
|---|---|---|---|
| Radionuclide | Yttrium-90 | Holmium-166 | |
| Radionuclide properties | |||
| T 1/2 (h) | 64.1 | 26.8 | |
| Maximum β−-energy (MeV) | 2.28 (99.9%) | 1.77 (48.7%), 1.85 (50.0%) | |
| γ-Energy (keV) | No γ-emission | 80.6 (6.7%) | |
| Neutron cross-section (barn) | 1.3 | 64 | |
| Matrix material | Glass | Resin | Poly(l-lactic acid) |
| Density (g/ml) | 3.3 | 1.6 | 1.4 |
| Diameter (μm) | 25 ± 10 | 32 ± 10 | 30 ± 5 |
| Activity/microsphere (Bq) | 1,250a−2,500 | 50a | 450a |
| Number of microspheres per dose | 4,000,000 | 50,000,000 | 33,000,000 |
aCalculated values