TY - JOUR T1 - Initial Direct Comparison of <sup>99m</sup>Tc-TOC and <sup>99m</sup>Tc-TATE in Identifying Sites of Disease in Patients with Proven GEP NETs JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1060 LP - 1065 DO - 10.2967/jnumed.107.046961 VL - 49 IS - 7 AU - Jaroslaw B. Cwikla AU - Renata Mikolajczak AU - Dariusz Pawlak AU - John R. Buscombe AU - Anna Nasierowska-Guttmejer AU - Andrzej Bator AU - Helmut R. Maecke AU - Jerzy Walecki Y1 - 2008/07/01 UR - http://jnm.snmjournals.org/content/49/7/1060.abstract N2 - The imaging of neuroendocrine tumors has become one of the most significant areas in nuclear oncology. In an attempt to provide high-quality imaging and possible sensitivity at a reduced cost, time, and radiation dose, several 99mTc agents have been proposed. The aim of this initial study was to compare the tumor uptake and biodistribution of 2 new 6-hydrazinopyridine-3-carboxylic acid (HYNIC)–derivatized Tyr3-octreotide analogs, 99mTc-[HYNIC,Tyr3]octreotide (99mTc-TOC) and 99mTc-[HYNIC,Tyr3,Thr8]octreotide (99mTc-TATE), in patients with somatostatin receptor–expressing tumors. Methods: Each of 12 patients with proven gastrointestinal pancreatic neuroendocrine tumors received a mean activity of 520 MBq of 99mTc-TOC and 99mTc-TATE. Scintigraphy with both tracers was performed 3–4 h after their injection using standard whole-body and SPECT imaging. The images were reviewed subjectively by 2 readers, who reported tumor uptake lesion by lesion. Results: Both radiotracers demonstrated concordance between the results in 7 patients (58%). In total, 110 sites of disease were identified with 99mTc-TOC, compared with 115 with 99mTc-TATE. There was 1 case in which 99mTc-TOC identified sites of disease not seen on 99mTc-TATE imaging but 4 cases in which some sites of disease were seen with 99mTc-TATE and not 99mTc-TOC. Conclusion: In this initial study, both tracers seem to show similar sites of tumor, with 99mTc-TATE having a slight edge in the total number of lesions seen, especially in lymph node metastases. ER -