Uptake Fractions and Effective Half-Lives for Iodine-131*
| Medical condition | Extrathyroidal component | Thyroidal component | ||
|---|---|---|---|---|
| Uptake fraction F1 | Effective half-life T1eff (day) | Uptake fraction F2 | Effective half-life T2eff (day) | |
| Hyperthyroidism | 0.20 | 0.32 | 0.80 | 5.2 |
| Post-thyroidectomy for thyroid cancer | 0.95 | 0.32 | 0.05 | 7.3 |
↵* From Table B-1 in NRC Regulatory Guide 8.39.