Longitudinal microPET imaging of brain tumor growth with F-18-labeled RGD peptide.

Purpose: EMD 121974, a potent cyclic RGD peptide inhibitor of alphav-integrins, demonstrated effectiveness in suppressing brain tumor growth in both preclinical models and phases I/II clinical trials. The ability to non-invasively evaluate alphav-integrin expression provides a novel and unique way to better understand brain tumor angiogenesis in relationship to alphav-integrin expression, and allow for direct assessment of anti-integrin treatment efficacy.

Procedures: We developed a F-18-labeled RGD peptide [F-18]FB-RGD and performed serial microPET imaging scans to follow brain tumor growth and angiogenesis as a function of time in an orthotopic U87MG glioblastoma xenograft model in athymic nude mice.

Results: The tumor was barely visible on microPET at the size of
Conclusions: Longitudinal microPET imaging and [F-18]FB-RGD provides the sensitivity and resolution to visualize and quantify anatomical variations during brain tumor growth and angiogenesis, most likely through interaction with alphav-integrins expressed on tumor cells and angiogenic tumor vessels.