Values of 99mTc-methoxyisobutylisonitrile imaging after first-time large-dose 131I therapy in treating differentiated thyroid cancer

Xiaomei Pan, Dong Duan, Yuquan Zhu, Hua Pang, Lili Guan, Zhixiang Lv Department of Nuclear Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China Objective: The aim of this study is to investigate the use of 99mTc-methoxyisobutylisonitrile (MIBI) imaging for evaluating the treatment response of differentiated thyroid cancer (DTC) after the first administration of a high dose of 131I.Methods: Patients with DTC who received 131I therapy underwent 99mTc-MIBI imaging after successive increases in the therapeutic dose of 131I, and the serum levels of thyroglobulin (Tg) were measured.Results: A total of 191 patients were enrolled in the final analysis, including 65 metastases and/or thyroid remnant-positive patients (22 patients with metastases and 43 patients with thyroid remnants). The sensitivity of 99mTc-MIBI imaging for detecting positive cases and thyroid remnants was 56.9% and 39.5%, respectively, which was significantly lower than that of 131I imaging (92.3% and 100%, respectively, P0.05). The Tg levels in the positive group were significantly higher than that in the negative group (P