@article{QIMS155122,
author = {Rongqin Zhang and Huiting Yang and Yan Zou and Yong Zhao and Rongfang Shen and Zhanwen Zhang},
title = {Comparison between 99mTcO4− SPECT/CT and diagnostic 131I SPECT/CT for the detection of postoperative thyroid remnant in patients with differentiated thyroid cancer},
journal = {Quantitative Imaging in Medicine and Surgery},
volume = {16},
number = {7},
year = {2026},
keywords = {},
abstract = {Background: Accurate imaging evaluation of remnant thyroid tissue (RTT) is particularly important for precise radioiodine remnant ablation (RRA). However, the optimal imaging method to guide its management remains a subject of debate. This study compared the diagnostic value of 99mTcO4− single photon emission computed tomography/computed tomography (SPECT/CT; Tc-99m scan) and diagnostic 74 MBq 131I whole body scan with SPECT/CT (Dx scan) for detecting RTT in differentiated thyroid cancer patients after total thyroidectomy, to guide subsequent RRA strategy.Methods: A total of 505 patients undergoing radioactive iodine (RAI) therapy were enrolled and had no cervical lymph node metastases or distant metastasis in postablation 131I SPECT/CT (Rx scan). The thyroid bed area was divided into 8 regions on SPECT/CT. RTTs on Tc-99m scan and Dx scan were counted and analyzed. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of Tc-99m scan and Dx scan for detecting RTT were compared. Associations of serum stimulated thyroglobulin (sTg), thyroglobulin antibody (TgAb), and sTg/thyroid-stimulating hormone (TSH) with findings across all scan modalities were analyzed. The ablation success rates in different groups were assessed.Results: Per-patient analysis showed that Dx scan had significantly higher sensitivity (95.3%) and NPV (34.3%) than Tc-99m scan (66.1% and 6.7%, respectively). Both modalities achieved 100% specificity and PPV. Rx SPECT/CT detected 1,057 radioiodine-uptake foci in 493 patients, with the majority of RTT situated in the superior anterior region (SAR) and posterolateral regions. In the per-site analysis, the overall sensitivity, specificity, PPV, and NPV of Tc-99m scan for detecting RTT were 47.3%, 100%, 100%, and 84.3%, respectively, compared with 86.7%, 100%, 100%, and 95.5% for Dx scan. sTg levels were significantly higher in both Tc-99m scan-positive and Dx scan-positive patients than those in negative patients (2.12 vs. 0.33 ng/mL, P},
issn = {2223-4306}, url = {https://qims.amegroups.org/article/view/155122}
}