Figure 2.

Tumor heterogeneity in a patient with a G3 gastric neuroendocrine tumor (NET) and liver metastases (patient #11; Ki67: 90%). In accordance with G3 NET, hypermetabolic hepatic metastases demonstrate loss of somatostatin receptor (SSTR) and up-regulation of CXCR4 expression (solid arrows, corresponding SUV_max: 10.3 for [⁶⁸Ga]Pentixafor, and 3.8 for [⁶⁸Ga]DOTATOC, respectively). Moreover, [⁶⁸Ga]Pentixafor provides additional information on disease extent by exclusively detecting a coeliacal lymph node suspicious for metastatic disease (dotted arrows). All transaxial PET/(CT) images are displayed identically with a window level between 0 and 5.5. [⁶⁸Ga]DOTATOC = ⁶⁸Ga-DOTA-D-Phe-Tyr3-octreotide, [¹⁸F]FDG = ¹⁸F-fluorodeoxy-glucose.