Recommended Administered Activity When RAI is Used for Remnant Ablation, Adjuvant Treatment, or Treatment of Known Residual Disease (1)
| Recommendation no. | ATA guidance |
| 55A | If radioactive iodine remnant ablation is performed after total thyroidectomy for ATA low risk thyroid cancer or intermediate risk disease with lower features (i.e., low-volume central neck nodal metastasis with no other known gross residual disease or any other adverse features), a low administered activity of approximately 30 mCi is generally favored over higher administered activities. (Weak recommendation, Low quality evidence) |
| 55B | Higher administered activities may need to be considered for patients receiving less than total or near total thyroidectomy in which a larger remnant is suspected or in which adjuvant therapy is intended. (Weak recommendation, Low quality evidence) |
| 56 | When radioactive iodine is intended for initial adjuvant therapy to treat suspected microscopic residual disease, administered activities above those used for remnant ablation up to 150 mCi are generally recommended (in the absence of known distant metastases). It is uncertain whether routine use of higher administered activities (> 150 mCi) in this setting will reduce structural disease recurrence for T3 and N1 disease. (Weak recommendation, Low quality evidence) |
| 77B | The selection of RAI activity to administer for pulmonary micrometastasis can be empiric (100 to 200 mCi, or 100 to 150 mCi for patients ≥ 70 years old) or estimated by dosimetry to limit whole body retention to 80 mCi at 48 hours and 200 cGy to the bone marrow. (Strong recommendation, Moderate quality evidence) |
| 78 | Radioiodine avid macronodular metastasis may be treated with radioactive iodine and treatment may be repeated when objective benefit is demonstrated (decrease in the size of the lesions, decreasing thyroglobulin), but complete remission is not common and survival remains poor. The selection of RAI activity to administer can be made empirically (100-200 mCi) or by lesion dosimetry or whole body dosimetry if available to limit whole body retention to 80 mCi at 48 hours and 200 cGy to the bone marrow. (Weak recommendation, Low quality evidence) |
| 79 | With regard to treatment of bone metastases, the RAI activity administered can be given empirically (100 to 200 mCi) or determined by dosimetry. (Weak recommendation, Low quality evidence) |
1 mCi = 37 MBq.