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Characteristics of some radioisotopes
| Isotope (decay) | t 1/2 | Endpoint energy (keV) | Fraction above CT (%) | |
|---|---|---|---|---|
| water | tissue | |||
| (n=1.33) | (n=1.4) | |||
| 18F (β +) | 109.8 min | 633 | 42 | 58 |
| 90Y (β −) | 64.1 h | 2280 | 90 | 93 |
| 131I (β −) | 8.02 days | 606 | 25 | 37 |
CT = Cerenkov threshold
