GIÁ TRỊ CỦA SPECT/CT SO VỚI XẠ HÌNH TOÀN THÂN TRONG ĐÁNH GIÁ UNG THƯ TUYẾN GIÁP THỂ BIỆT HÓA SAU ĐIỀU TRỊ I-131

Abstract

Objective: To compare the value of SPECT/CT imaging with whole-body scintigraphy (WBS) in detecting lesions and assessing disease staging in patients with differentiated thyroid cancer (DTC) after surgery and radioactive iodine (I-131) treatment. Subjects and Methods: A cross-sectional descriptive study (including retrospective and prospective data) was conducted on 67 DTC patients who underwent total or near-total thyroidectomy and received adjunctive I-131 treatment at the Department of Radiotherapy & Nuclear Medicine, E Hospital (7/2022 – 7/2024). All patients underwent WBS and SPECT/CT after ingesting a therapeutic dose of I-131. Imaging results were analyzed and compared regarding the number and location of uptake lesions, and correlated with pre-treatment stimulated thyroglobulin (Tg) levels (TSH > 30 mIU/L). Changes in disease staging (according to AJCC TNM classification) using SPECT/CT compared to WBS were also recorded. Data was processed using SPSS software version 22.0. Results: SPECT/CT detected a total of 126 radioactive uptake lesions, significantly higher than the 73 lesions found by WBS. Notably, SPECT/CT identified additional distant metastases (1 bone lesion, 1 lung lesion) that were not detected by WBS. Consequently, SPECT/CT altered the staging of 4 patients (6.0%), including 2 cases of additional cervical lymph node metastasis and 2 cases of distant metastasis. Regarding biological correlation, among patients with Tg < 10 ng/ml, only 4/37 cases had lymph node metastasis and no distant metastasis; whereas in the group with Tg ≥ 10 ng/ml, 28/30 cases had lymph node metastasis and 2/30 had distant metastasis. Conclusion: SPECT/CT provides important supplementary diagnostic information compared to WBS in post-I-131 treatment monitoring of differentiated thyroid cancer. SPECT/CT allows more accurate detection of metastatic lesions, thereby improving staging accuracy and supporting treatment management. Therefore, SPECT/CT should be considered for routine use, particularly in cases with high- risk Tg ≥ 10 ng/ml or suspected distant metastasis.