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This Article Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Cook, J. Articles by Goldsmith, S. PubMed Articles by Cook, J. Articles by Goldsmith, S.

Stunning of I-131 uptake in treatment of Graves' disease: Relationship to treatment failure

¹ Nuclear Medicine, NYPH-Weill Cornell, New York, New York; ² Faculty of Health Science, University of Auckland, Auckland, New Zealand

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Objectives: To determine if stunning occurs in I-131 therapy [Rx] of Graves' disease and if so, to identify possible contributing factors and clinical significance.

Methods: Retrospective review of I-131 Rx of hyperthyroid patients [pts] over a 4 yr period [01/01/04-12/31/07] during which 24 hr post-Rx uptakes were obtained and compared to pre-Rx values. Stunning was defined as a 10% decrease in the post-Rx RAIU from the pre-Rx value (ratio of 24 hr I-131 Rx/ Dx <0.90. Comparison of age, gender, admin dose (MBq) and planned radiation absorbed dose(cGy)were reviewed for stunned [St] and nonstunned [NonSt] pts.

Results: Of 240 pts treated with I-131 for hyperthyroidism, 24 (10%) showed evidence of stunning. St pts were significantly older, 54.5 y (range 29-84) compared to NonSt: 45.7 y (range 7-95) (p=0.01 t-test). 85% of NonSt pts were female compared to 75% St pts(NS; p = 0.2 chi-square). No statistical difference in MBq dose for St pts: 451 MBq (range 185 – 1110 MBq) vs NonSt: 425 MBq (range 92 – 1110 MBq) (p=0.6 t-test). cGy was also similar between the St pts: 121 Gy (range 70 – 250 Gy) and NonSt pts: 110 Gy (range 90 – 250 Gy) (p=0.3 t-test). 17/24 (71%) St pts received supplemental I-131 to achieve the originally intended thyroid dose [MBq & cGy]; 1/17 [6%] Rx with supplemental I-131 had persistant or relapsed Graves' whereas 3/7 [43%] St pts not given supplemental I-131 relapsed or persisted (p=0.06, Fisher exact test).

Conclusions: Stunning by the Rx dose was observed in 10% of I-131 Rx hyperthyroid pts. Since data on only 24 pts is available, this study lacks statistical power to convincingly identify other determinants; however, a supplemental dosing regimen for stunned thyroids may reduce the likelihood of recurrence or persistance of hyperthyroidism.

This Article Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Cook, J. Articles by Goldsmith, S. PubMed Articles by Cook, J. Articles by Goldsmith, S.