The incidence of thyroid cancer in several affluent countries has markedly increased (1). Although mortality from thyroid cancer has remained relatively low and stable or has steadily declined in these and other countries (2).~Therefore, it is still important to identify markers for prognosis prediction and decision-making before radioactive iodine therapy (RIT). Various factors have been reported to be associated with the clinical outcome of RIT. These include preablative stimulated thyroglobulin (ps- Tg), tumor size, extrathyroidal invasiveness, cervical lymph node metastasis and TSH [3,4].~99mTc pertechnetate is a radiopharmaceutical used for thyroid scintigraphy. The photon energy of 140kev is ideally suited for use with gamma camera. It has short half life of about 6-hoursand no particulate emissions. 99mTc-pertechnetate scintigraphy is a simple, economic and RIT non-interfering technique to evaluate the volume of residual thyroid tissue(RTT). The 99m Tc-pertechnetate uptake of the thyroid bed can be used as a marker of RTT. Although negative uptake doesn't indicate the absence of RTT, it could suggest a small volume. On the other hand, positive uptake can be considered as a large volume of RTT. Several studies have reported that patients with negative 99mTc-pertechnetate uptake have a much higher chance of successful ablation[5, 6].~We hypothesized that negative 99mTc-pertechnetate scintigraphy is a significant predictor for excellent response (ER) to RIT in American Thyroid Association 2015(ATA) low- and intermediate risk DTC patient according to .
The aim of this study is to evaluate the prognostic value of postoperative99mTc-pertechnetate scanning in patients with DTC.