Tomography of epidermal growth factor receptor binding to fluorescent Affibody in vivo studied with magnetic resonance guided fluorescence recovery in varying orthotopic glioma sizes

Robert W. Holt; Jennifer-Lynn H. Demers; Kristian J. Sexton; Jason R. Gunn; Scott C. Davis; Kimberley S. Samkoe; Brian W. Pogue

doi:10.1117/1.JBO.20.2.026001

4 February 2015 Tomography of epidermal growth factor receptor binding to fluorescent Affibody in vivo studied with magnetic resonance guided fluorescence recovery in varying orthotopic glioma sizes

Robert W. Holt, Jennifer-Lynn H. Demers, Kristian J. Sexton, Jason R. Gunn, Scott C. Davis, Kimberley S. Samkoe, Brian W. Pogue

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Journal of Biomedical Optics, Vol. 20, Issue 2, 026001 (February 2015). https://doi.org/10.1117/1.JBO.20.2.026001

Abstract

The ability to image targeted tracer binding to epidermal growth factor receptor (EGFR) was studied in vivo in orthotopically grown glioma tumors of different sizes. The binding potential was quantified using a dual-tracer approach, which employs a fluorescently labeled peptide targeted to EGFR and a reference tracer with similar pharmacokinetic properties but no specific binding, to estimate the relative bound fraction from kinetic compartment modeling. The recovered values of binding potential did not vary significantly as a function of tumor size (1 to 33 mm³), suggesting that binding potential may be consistent in the U251 tumors regardless of size or stage after implantation. However, the fluorescence yield of the targeted fluorescent tracers in the tumor was affected significantly by tumor size, suggesting that dual-tracer imaging helps account for variations in absolute uptake, which plague single-tracer imaging techniques. Ex vivo analysis showed relatively high spatial heterogeneity in each tumor that cannot be resolved by tomographic techniques. Nonetheless, the dual-tracer tomographic technique is a powerful tool for longitudinal bulk estimation of receptor binding.

CC BY: © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Robert W. Holt, Jennifer-Lynn H. Demers, Kristian J. Sexton, Jason R. Gunn, Scott C. Davis, Kimberley S. Samkoe, and Brian W. Pogue "Tomography of epidermal growth factor receptor binding to fluorescent Affibody in vivo studied with magnetic resonance guided fluorescence recovery in varying orthotopic glioma sizes," Journal of Biomedical Optics 20(2), 026001 (4 February 2015). https://doi.org/10.1117/1.JBO.20.2.026001

Published: 4 February 2015

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