Fig. 1Postoperative technetium-99m (99mTc)-pertechnetate scintigraphy (A) showing multiple uptake foci (arrows) (uptake rate 1.3%), whole body scan (WBS) with additional single photon emission computed tomography/computed tomography, (B) showing a corresponding intensely iodine-avid remnants (arrows), and (C) diagnostic WBS performed 6 months later showing two areas of persisting faint uptake (arrows) in a 47 years old woman with papillary thyroid carcinoma pT2pN0 (preablation stimulated thyroglobulin, 4.4 ng/mL; response assessment: basal [0.4 ng/mL] and stimulated [1.2 ng/mL] thyroglobulin, respectively). Response assessment: unsuccessful ablation.
Fig. 2Postoperative technetium-99m (99mTc)-pertechnetate scintigraphy (A) with no visually discernable neck uptake, whole body scan (WBS) with additional single photon emission computed tomography/computed tomography, (B) showing a iodine-avid remnant, and (C) diagnostic WBS performed 6 months later showing complete ablation in a 32 years old female with papillary thyroid carcinoma pT2pNx (stimulated thyroglobulin: preablation, 1.2 ng/mL; response assessment <0.15 ng/mL). Response assessment: successful ablation.
Fig. 3Receiving Operator Characteristics curve analysis for preablation technetium-99m (99mTc)-pertechnetate uptake rate (A) and stimulated thyroglobulin (sTg) (B) to predict successful ablation. The optimal cutoffs (arrows) were 0.9% (sensitivity 70%, specificity 55%; area under the curve, 0.710; P=0.020) and 0.8 ng/mL (sensitivity 65%, specificity 67%; area under the curve, 0.620; P=0.025) for predicting successful routine radioiodine ablation.
Table 1Demographic, Clinical, Pathological, and Biochemical Data of Enrolled Patients
Factor |
Value |
Age, yr |
45.8±14.2 |
Female sex |
147 (76) |
Tumor size, mm |
22.3±10.5 |
Tumor classification (pT1b/T2) |
75/118 |
LN classification (pNx/N1) |
161/32 |
Preablation sTg, ng/mL |
2.74 (<0.1–78.9) |
Table 2Preablative 99mTc-Pertechnetate Scintigraphy and Thyroglobulin Results in Ablated and Non-Ablated Differentiated Thyroid Carcinoma Patients
Factor |
Ablated (n=143) |
Non-ablated (n=26) |
P value |
Age, yr |
45.8±14.2 |
52.3±17.5 |
NS |
Female sex |
127 (88) |
21 (80) |
NS |
Tumor size |
24.6±9.9 |
19.8±15.5 |
NS |
Tumor classification (T1b/T2) |
64/79 |
11/15 |
NS |
Preablation sTg, ng/mL |
2.7 (<0.15–9.6) |
5.8 (<0.15–78.9) |
<0.010 |
Preablation sTg >1 ng/mL |
91 (64) |
23 (88) |
NS |
Preablation sTg >2 ng/mL |
72 (50) |
17 (65) |
NS |
99mTc-pertechnetate scan (positive) |
74 (52) |
25 (96) |
<0.001 |
99mTc-uptake rate, % |
0.1 (0.1–1.4) |
0.6 (0.2–5.6) |
0.050 |