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Journal of Biomedicine and Biotechnology
Volume 2011, Article ID 267206, 9 pages
http://dx.doi.org/10.1155/2011/267206
Research Article

Development of 68Ga-Glycopeptide as an Imaging Probe for Tumor Angiogenesis

1Division of Diagnostic Imaging, University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
2Chemistry, Manufacturing and Control, SeeCure LLC, Houston, TX 77036, USA
3Innovation Center, Taiwan HOPAX Chems, MFG, Company Ltd., Kaohsiung 831, Taiwan
4Department of Nuclear Medicine, National Taiwan University Hospital, Taipei 100, Taiwan

Received 28 December 2010; Accepted 15 February 2011

Academic Editor: Lie-Hang Shen

Copyright © 2011 Ning Tsao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective. This study was aimed to study tissue distribution and tumor imaging potential of 68Ga-glycopeptide (GP) in tumor-bearing rodents by PET. Methods. GP was synthesized by conjugating glutamate peptide and chitosan. GP was labeled with 68Ga chloride for in vitro and in vivo studies. Computer outlined region of interest (counts per pixel) of the tumor and muscle (at the symmetric site) was used to determine tumor-to-muscle count density ratios. To ascertain the feasibility of 68Ga-GP in tumor imaging in large animals, PET/CT imaging of 68Ga-GP and 18F-FDG were conducted in New Zealand white rabbits bearing VX2 tumors. Standard uptake value of tumors were determined by PET up to 45 min. To determine blood clearance and half-life of 68Ga-GP, blood samples were collected from 10 seconds to 20 min. Results. Radiochemical purity of 68Ga-GP determined by instant thin-layer chromatography was >95%. Tumor uptake values (SUV) for 68Ga-GP and 18F-FDG in New Zealand white rabbits bearing VX2 tumors were 3.25 versus 7.04. PET images in tumor-bearing rats and rabbits confirmed that 68Ga-GP could assess tumor uptake. From blood clearance curve, the half-life of 68Ga-GP was 1.84 hr. Conclusion Our data indicate that it is feasible to use 68Ga-GP to assess tumor angiogenesis.