Stunning effects after a diagnostic dose of Iodine-131

Chia Hung Kao*, Tzu Chen Yen

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

43 Scopus citations


Aim: To understand stunning effects of a diagnostic dose of iodine-131 (I-131). Methods: Four hundred and sixty-eight patients (101 males, 367 females, ages: 6-75 years) with well differentiated thyroid cancer, following total or nearly total thyroidectomy, were studied. One hundred and eleven MBq (3 mCi) diagnostic (Dx) doses of I-131 whole body scan (WBS) were obtained after withholding thyroxine after 6 weeks and triiodothyronine for 2 weeks. One week to one month later, 3.7-7.4 GBq (100-200 mCi) I-131 was given to them, then simulating hormone level was usually above 30 μIU/ml. Results: Of the 468 patients, 344 (73.5%) has scintigraphic patterns of apparently decreased uptake in 240 thyroid remnants and 104 metastatic lesions on the Tx dose of I-131 WBS compared to Dx dose of I-131 WBS. Stunning phenomenon occurred in 50 cases, including 42 thyroid remnants and 18 metastatic lesions. Conclusion: Dx dose of I-131 influence the uptake of a subsequently administered Tx dose of I-131.

Original languageEnglish
Pages (from-to)23-25
Number of pages3
Issue number1
StatePublished - 01 1998
Externally publishedYes


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