title: Stunning phenomenon after a radioactive iodine- ¹³¹I diagnostic whole-body scan: Is it really a point of clinical consideration?
abstract: OBJECTIVE
  Stunning of thyroid remnants after diagnostic scanning (Dx-WBS) using radioactive iodine- (¹³¹I) may limit the efficacy of I therapy. We aimed to evaluate this assumption in a prospectively designed study.
  
  
  METHODS
  Forty patients who underwent thyroidectomy for differentiated thyroid carcinoma were studied and divided into two identical groups: G1 and G2. In the G1 group, no Dx-WBS was performed and the ablation dose was given directly on the basis of the risk stratification; in the G2 group, Dx-WBS was performed with 185 MBq (5 mCi) of ¹³¹I, and ablation was given for a mean number of 11 ± 1.1 days; stunning was found on a semiquantitative basis in all patients. At a mean of 6.5 ± 0.3 months, the ablation success rate (ASR) was evaluated on the basis of Dx-WBS, thyroglobulin levels, and neck sonography. Complete ASR was considered when no ¹³¹I uptake could be seen in the neck or elsewhere, thyroglobulin was less than 2 ng/ml, and neck sonography was negative for any disease-related abnormalities.
  
  
  RESULTS
  G1 and G2 groups were completely identical as no significant differences were found between their different characteristics, including the mean ablative dose. ASR was 81.7 and 78.3% in G1 and G2 groups, respectively (P=0.6). Multivariate Cox regression analysis showed the mean ablation dose to be the most influential factor in ASR (odds ratio 1.045; 95% confidence interval 0.936-1.1189; P=0.01).
  
  
  CONCLUSIONS
  Our data suggest that stunning had no influence on ASR and is not a point of clinical consideration with respect to this aspect.
authors.affiliation: Nuclear Medicine Department, Faculty of Medicine, Cairo University, Cairo, Egypt. amramin67@gmail.com
authors.forename: Amr
authors.initials: A
authors.lastname: Amin
authors.forename: Mahasen
authors.initials: M
authors.lastname: Amin
authors.forename: Ahmed
authors.initials: A
authors.lastname: Badwey
mesh_terms: D055011:Ablation Techniques; D000328:Adult; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D016896:Treatment Outcome; D051598:Whole Body Imaging; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes