Functional imaging of neuroendocrine tumors with combined PET/CT using ⁶⁸Ga‐DOTATATE (DOTA‐<scp>D</scp>Phe¹,Tyr³‐octreotate) and ¹⁸F‐FDG

<jats:title>Abstract</jats:title><jats:sec><jats:title>BACKGROUND.</jats:title><jats:p>The aim was to assess the relevant distribution of the novel PET tracer <jats:sup>68</jats:sup>Ga‐DOTATATE in neuroendocrine tumors (NETs) with combined positron emission tomography / computed tomography (PET/CT) and compare its performance with that of <jats:sup>18</jats:sup>F‐FDG PET/CT.</jats:p></jats:sec><jats:sec><jats:title>METHODS.</jats:title><jats:p>The imaging findings with <jats:sup>68</jats:sup>Ga‐DOTATATE and <jats:sup>18</jats:sup>F‐FDG on 38 consecutive patients with a diagnosis of primary or recurrent NET were compared and correlated with tumor grade on histology based on ki67 and mitotic index.</jats:p></jats:sec><jats:sec><jats:title>RESULTS.</jats:title><jats:p>The sensitivity of <jats:sup>68</jats:sup>Ga‐DOTATATE PET/CT was 82% (31 of 38) and that of <jats:sup>18</jats:sup>F‐FDG PET/CT was 66% (25 of 38). The sensitivity of combined <jats:sup>68</jats:sup>Ga‐DOTATATE and <jats:sup>18</jats:sup>F‐FDG PET/CT was 92% (35 of 38). There was greater uptake of <jats:sup>68</jats:sup>Ga‐DOTATATE than <jats:sup>18</jats:sup>F‐FDG in low‐grade NET (median SUV 29 vs 2.9, <jats:italic>P</jats:italic> < .001). In high‐grade NET there was higher uptake of <jats:sup>18</jats:sup>F‐FDG over <jats:sup>68</jats:sup>Ga‐DOTATATE (median SUV 11.7 vs 4.4, <jats:italic>P</jats:italic> = .03). There was a significant correlation with predominant tumor uptake of <jats:sup>68</jats:sup>Ga‐DOTATATE or <jats:sup>18</jats:sup>F‐FDG and tumor grade on histology (<jats:italic>P</jats:italic> < .0001).</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS.</jats:title><jats:p><jats:sup>68</jats:sup>Ga‐DOTATATE PET/CT is a useful novel imaging modality for NETs and is superior to <jats:sup>18</jats:sup>F‐FDG for imaging well‐differentiated NET. Functional imaging with both <jats:sup>68</jats:sup>Ga‐DOTATATE and <jats:sup>18</jats:sup>F‐FDG has potential for a more comprehensive tumor assessment in intermediate‐ and high‐grade tumors. Cancer 2008. ©2008 American Cancer Society.</jats:p></jats:sec>