Meningiomas: A Comparative Study of 68Ga-DOTATOC, 68Ga-DOTANOC and 68Ga-DOTATATE for Molecular Imaging in Mice

Purpose: The goal of this study was to compare the tumor uptake kinetics and diagnostic value of three Ga-68-DOTA-labeled somatostatin analogues (Ga-68-DOTATOC, Ga-68-DOTANOC, and Ga-68-DOTATATE) using PET/CT in a murine model with subcutaneous meningioma xenografts. Methods: The experiment was performed with 16 male NUDE NU/NU mice bearing xenografts of a human meningioma cell line (CH-157MN). Ga-68-DOTATOC, Ga-68-DOTANOC, and Ga-68-DOTATATE were produced in a FASTLab automated platform. Imaging was performed on an Argus small-animal PET/CT scanner. The SUVmax of the liver and muscle, and the tumor-to-liver (T/L) and tumor-to-muscle (T/M) SUV ratios were computed. Kinetic analysis was performed using Logan graphical analysis for a two-tissue reversible compartmental model, and the volume of distribution (V-t) was determined. Results: Hepatic SUVmax and V-t were significantly higher with Ga-68-DOTANOC than with Ga-68-DOTATOC and Ga-68-DOTATATE. No significant differences between tracers were found for SUVmax in tumor or muscle. No differences were found in the T/L SUV ratio between Ga-68-DOTATATE and Ga-68-DOTATOC, both of which had a higher fraction than Ga-68-DOTANOC. The T/M SUV ratio was significantly higher with Ga-68-DOTATATE than with Ga-68-DOTATOC and Ga-68-DOTANOC. The V-t for tumor was higher with Ga-68-DOTATATE than with Ga-68-DOTANOC and relatively similar to that of Ga-68-DOTATOC. Conclusions: This study demonstrates, for the first time, the ability of the three radiolabeled somatostatin analogues tested to image a human meningioma cell line. Although V-t was relatively similar with Ga-68-DOTATATE and Ga-68-DOTATOC, uptake was higher with Ga-68-DOTATATE in the tumor than with Ga-68-DOTANOC and Ga-68-DOTATOC, suggesting a higher diagnostic value of Ga-68-DOTATATE for detecting meningiomas.