PET imaging of insulinoma using 18F-FBEM-EM3106 B, a new GLP-1 analog

Wednesday, October 26, 2011 — Poster Session III
10:00 a.m. – Noon	Natcher Conference Center	NIBIB	IMAG-10

Authors

• HK Gao
• G Niu
• M Yang
• QM Quan
• D Kiesewetter
• XY Chen

Abstract

Insulinomas express glucagon-like peptide-1 (GLP-1) receptor with high density and incidence. In this study, we labeled a novel GLP-1 analog, EM3106B, with 18F and performed PET imaging to visualize insulinoma tumors in an animal model. Methods: A multiple lactam bridges containing GLP-1 analog, EM3106B was labeled with 18F. The newly developed tracer was characterized by cell based receptor-binding assay, cell uptake and efflux assay. In vivo PET imaging was performed in nude mice bearing subcutaneous INS-1 tumors and MDA-MB-435 tumors. Results: EM3106B showed high binding affinity, high cell uptake and metabolism stability. The INS-1 tumors were clearly visible with high contrast in relation to the contralateral background on PET images and tumor uptake of 18F- FBEM- EM3106B was determined to be 28.5 ± 4.74, 25.4 ± 4.06% ID/g at 60 and 120 min, respectively. 18F- FBEM-EM3106B showed very low uptake in MB-MDA-435 tumors due to the relatively low expression of GLP-1R. Conclusion: 18F-FBEM-EM3106B exhibited specific receptor targeting properties for insulinomas. The favorable characteristics of 18F-FBEM-EM3106B, such as high specific activity and high tumor uptake, and high tumor to non-target uptake, demonstrate that it is a promising tracer for clinical insulinoma imaging.

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