title: The correlation of post-operative radioiodine uptake and Tc-99m pertechnetate thyroid scintigraphy and the result of thyroid remnant ablation.
abstract: OBJECTIVE
  Determine the relationship between postoperative thyroid remnant using 24 h radioiodine uptake and Tc-99m pertechnetate scintigraphy, and the success of high dose radioiodine ablation.
  
  
  METHODS
  Retrospectively enrolled 250 patients with DTC who underwent thyroidectomy and radioiodine ablation. Postoperative Tc-99m pertechnetate and 24 h 1-131 uptake were reviewed to evaluate thyroid remnant and the directly compared with ablation outcome. The successful ablation was defined using negative WBS and stimulated Tg < 10 ng/ml in the absence of TgAb at six to 12 months after treatment. The relationship between success of ablation and other variables were evaluated
  
  
  RESULTS
  One hundred twenty four patients (49.6%) were successfully ablated after single high dose radioiodine ablation. The authors found no association with age, sex, extent of surgery, tumor histology, tumor size, mutifocal, extrathyroidal invasion, 1-131 administered dose, interval from surgery to radioiodine ablation, Tc-99m pertechnetate scan, or 24 h 1-131 uptake, and successful ablation. The initial Tg level was the only variable found to be associated with success (p < 0.001).
  
  
  CONCLUSIONS
  Neither Tc-99m pertechnetate thyroid scintigraphy nor 24 h 1-131 uptake percentage in the evaluation of postsurgical thyroid remnant can predict radioiodine ablation outcome in patients with DTC. Serum Tg level at the time of ablation could be a reasonable predictor of the success of ablation.
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. stanyalu@hotmail.com
authors.forename: Tanyaluck
authors.initials: T
authors.lastname: Thientunyakit
authors.forename: Pawana
authors.initials: P
authors.lastname: Pusuwan
authors.forename: Pongpija
authors.initials: P
authors.lastname: Tuchinda
authors.forename: Benjapa
authors.initials: B
authors.lastname: Khiewvan
authors.forename: Benjapa
authors.initials: B
authors.lastname: Kiewvan
mesh_terms: D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D013670:Sodium Pertechnetate Tc 99m; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy* / Q000601:surgery; D013965:Thyroidectomy; D016896:Treatment Outcome; D051598:Whole Body Imaging
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D013670:Sodium Pertechnetate Tc 99m