Positron emission tomography imaging of tumor angiogenesis and monitoring of antiangiogenic efficacy using the novel tetrameric peptide probe 64Cu-cyclam-RAFT-c(-RGDfK-)4.

"Conflict of interest The authors declare that they have no conflict of interest."

"We thank Mr. Hisashi Suzuki and other members of the Molecular Probe Program for 64Cu production; the Cyclotron Operation Section for cyclotron operation; Mr. Hidekatsu Wakizaka for operation and quality control of the PET scanner; and Ms. Chizuru Sogawa, Dr. Atsushi Tsuji, Dr. Winn Aung, and all the other members of the Diagnostic Imaging Program, Molecular Imaging Center, NIRS, for kindly helping with the animal experiments. This work was partly supported by a Grant-in-Aid for Scientific Research (C) (19591406) from the Ministry of Education, Culture, Sports, Science and Technology, Japan, and by Health and Labour Sciences Research Grants for Research on Hepatitis (Title: Development of early detection systems of liver cancer using molecular markers and diagnostic imagings) from the Ministry of Health, Labour and Welfare, Japan."