Sensitivity of pretargeted immunoPET using 68 Ga-peptide to detect colonic carcinoma liver metastases in a murine xenograft model: Comparison with 18 FDG PET-CT
Résumé
ABSTRACT Purpose: The aim of this study was to compare the performances pretargeted immunoPET 68 Ga-PETimaging (68 Ga-pPET) with anti carcino-embryonic antigen (CEA) and anti-histamine-succinyl-glycine (HSG) recombinant humanized bispecific monoclonal antibody (TF2) and 68 Ga-labeled HSG peptide (IMP288) to conventional 18 FDG-PET in an orthotopic murine model of liver metastases of human colonic cancer. Methods: Hepatic tumor burden following intra-portal injection of luciferase-transfected LS174T cells in nude mice was confirmed using bioluminescence. One group of animals was injected intravenously with TF2 and with 68 Ga-IMP288 24 hours later (n=8). Another group received 18 FDG (n=8), and a third had both imaging modalities (n=7). PET acquisitions started 1 hour after injection of the radioconjugate. Biodistributions in tumors and normal tissues were assessed one hour after imaging. Results: Tumor/organ ratios were significantly higher with 68 Ga-pPET compared to 18 FDG-PET (P<0.05) with both imaging and biodistribution data. 68 Ga-pPET sensitivity for tumor detection was 67% vs. 31% with 18 FDG PET (P=0.049). For tumors less than 200 mg, the sensitivity was 44% with 68 Ga-pPET vs. 0% for 18 FDG PET (P=0.031). A strong correlation was demonstrated between tumor uptakes measured on PET images and biodistribution analyses (r 2 =0.85). Conclusion: 68 Ga-pPET was more sensitive than 18 FDG-PET for the detection of human colonic liver metastases in an orthotopic murine xenograft model. Improved tumor/organ ratios support the use of pretargeting method for imaging and therapy of CEA-expressing tumors.
Domaines
CancerOrigine | Fichiers éditeurs autorisés sur une archive ouverte |
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