Figure 2

Molecular imaging with FDG- and Met-PET/CT.

Representative [¹⁸F]FDG images (transverse, sagittal, lateral) of established GC tumors after 7 (A), 14 (B) and 21 (C) days after subcutaneous injection of the cells. A longitudinal CT section is also shown in right bottom panels. White arrowheads mark the localization of the tumor. [¹⁸F]FDG uptake expressed as maximum standard uptake value (SUV) (D) and mean value (E) of established GC tumors after 7, 14 and 21 days after subcutaneous injection of the cells. (F) Tumor volumes derived from SUV data in GC tumor. (G) Representative [¹¹C]Met-PET (top) and [¹⁸F]FDG -PET (bottom) images (transverse, sagittal, lateral) of GC tumors 54 days after subcutaneous injection of the cells. Asterisks mark areas with reduced metabolic activity. (H) Top graph- Time activity curves of [¹¹C]Met-PET/CT: red- necrotic zone of the tumor, blue-active area of the tumor, black—muscle in contralateral hind leg. Bottom graph. Time-activity curve of the active and necrotic zone of the tumor showing tracer accumulation over the first approximately 10 min, followed by a plateau phase (plateau value: 559.7 kBq/cc; 95% confidence interval [479.4–640]). The data of the active area of the tumor fitted to a one phase association model (R²: 0.88; P < 0.05). (I) Kinetic analysis performed by fitting a standard 2-parameter, one-tissue compartment model to the dynamic PET data. k1 (transport from arterial plasma to tissue); k2 (transport from tissue to arterial plasma). K1 values are higher in the active part of the tumor active part and the necrotic and between active part and the muscle. (J) Same data for Vt, total distribution volume. *P < 0.05.