Empiric radioactive iodine dosing regimens frequently exceed maximum tolerated activity levels in elderly patients with thyroid cancer.

Abstract

Administered RAI activities of less than 5.18 GBq (140 mCi) rarely exposed blood to more than 200 cGy except in the very elderly. However, administered activities of 7.4-9.25 GBq (200-250 mCi) frequently exceeded the calculated MTA in patients 70 y old or older. Therefore, dosimetry-guided RAI therapy may be preferable to fixed-dose RAI treatment strategies in older patients with thyroid cancer and in patients with RAI-avid diffuse bilateral pulmonary metastases, even when renal function is normal.