title: Prediction of the success of thyroid remnant ablation using preablative 99mTc pertechnetate scintigraphy and postablative dual 131I scintigraphy.
abstract: OBJECTIVE
  The aim of this study was to predict the success of 131I ablation using preablative 99mTc pertechnetate salivary scintigraphy and a postablative dual 131I scan in differentiated thyroid cancer (DTC).
  
  
  METHODS
  A total of 168 DTC patients who underwent 131I ablation with preablative salivary scintigraphy and a postablative dual (early and delayed) 131I scan were enrolled. For salivary scintigraphy, the thyroid remnant uptake was visually assessed. For the dual 131I scan, the thyroid remnant to background uptake ratios (TBRs) on early and delayed scans were measured and the percentage change in TBR (TBRΔ) was calculated.
  
  
  RESULTS
  Thyroid remnant uptake was seen in 69 (41%) patients on salivary scintigraphy and in 162 (96%) patients on the dual 131I scan. The success rate of ablation was higher in patients with negative remnant uptake on salivary scintigraphy (86%) than in patients with positive remnant uptake (58%, P=0.0001). The success rate of ablation was 100% in patients with no remnant uptake on both salivary scintigraphy and the dual 131I scan. The success rate of ablation was higher in patients with TBRΔ 0 or more than in patients with TBRΔ less than 0, irrespective of remnant uptake on salivary scintigraphy (91 vs. 70%, P=0.03, for patients without remnant uptake on salivary scintigraphy; 74 vs. 48%, P=0.05, for patients with remnant uptake on salivary scintigraphy).
  
  
  CONCLUSIONS
  The success of thyroid remnant ablation in DTC can be predicted by the presence of remnant uptake on preablative 99mTc pertechnetate scintigraphy and change in remnant uptake on the postablative dual 131I scan.
authors.affiliation: Departments of aRadiology bNuclear Medicine cInternal Medicine dSurgery, Soonchunhyang University Hospital, Cheonan, Korea.
authors.forename: Jo Sung
authors.initials: JS
authors.lastname: Jung
authors.forename: Sang Mi
authors.initials: SM
authors.lastname: Lee
authors.forename: Sang Jin
authors.initials: SJ
authors.lastname: Kim
authors.forename: Jiyoun
authors.initials: J
authors.lastname: Choi
authors.forename: Sun Wook
authors.initials: SW
authors.lastname: Han
mesh_terms: D055011:Ablation Techniques; D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D012469:Salivary Glands / Q000000981:diagnostic imaging*; D013670:Sodium Pertechnetate Tc 99m; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D013965:Thyroidectomy; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes; D013670:Sodium Pertechnetate Tc 99m