BACKGROUND: The purpose of this study was to evaluate the relationship between postsurgical neck (⁹⁹m) technetium ((⁹⁹m) Tc)-pertechnetate uptake and the rate of successful remnant ablation after radioiodine treatment in patients with differentiated thyroid carcinoma (DTC). METHODS: Retrospectively enrolled were 232 patients with DTC who underwent total thyroidectomy and fixed activity ablation with 3.7 GBq ¹³¹I. The (⁹⁹m) Tc scans were performed on all patients before ¹³¹I administration. Thyroid ablation was assessed after 6 to 12 months by thyroid-stimulating hormone (TSH)-stimulated ¹³¹I-WBS and thyroglobulin measurement. The rate of successful ablation, occurrence of radioiodine-induced thyroiditis, and length of hospitalization were correlated with the (⁹⁹m) Tc-pertechnetate scintigraphy results. RESULTS: A (⁹⁹m) Tc uptake was significantly lower in ablated versus nonablated patients (p < .001). High (⁹⁹m) Tc-pertechnetate uptake, especially greater than 1.4%, predicted a high-risk of unsuccessful ablation. Higher (⁹⁹m) Tc-pertechnetate uptake was also related to prolonged hospitalization and the occurrence of radioiodine-induced thyroiditis. CONCLUSION: The (⁹⁹m) Tc-pertechnetate scintigraphy is a simple and feasible tool to evaluate thyroid remnants and to predict radioiodine ablation results in patients with DTC.
BACKGROUND: The purpose of this study was to evaluate the relationship between postsurgical neck (⁹⁹m) technetium ((⁹⁹m) Tc)-pertechnetate uptake and the rate of successful remnant ablation after radioiodine treatment in patients with differentiated thyroid carcinoma (DTC). METHODS: Retrospectively enrolled were 232 patients with DTC who underwent total thyroidectomy and fixed activity ablation with 3.7 GBq ¹³¹I. The (⁹⁹m) Tc scans were performed on all patients before ¹³¹I administration. Thyroid ablation was assessed after 6 to 12 months by thyroid-stimulating hormone (TSH)-stimulated ¹³¹I-WBS and thyroglobulin measurement. The rate of successful ablation, occurrence of radioiodine-induced thyroiditis, and length of hospitalization were correlated with the (⁹⁹m) Tc-pertechnetate scintigraphy results. RESULTS: A (⁹⁹m) Tc uptake was significantly lower in ablated versus nonablated patients (p < .001). High (⁹⁹m) Tc-pertechnetate uptake, especially greater than 1.4%, predicted a high-risk of unsuccessful ablation. Higher (⁹⁹m) Tc-pertechnetate uptake was also related to prolonged hospitalization and the occurrence of radioiodine-induced thyroiditis. CONCLUSION: The (⁹⁹m) Tc-pertechnetate scintigraphy is a simple and feasible tool to evaluate thyroid remnants and to predict radioiodine ablation results in patients with DTC.