This work was aimed at finding a 99Tcm-labeled tracer for tumor angiogenesis studies. Anti-angiogenesis peptides

with appropriate structural modified

were labeled with 99Tcm and screening in vivo on the tumor-bearing mice. The anti-angiogenesis peptide that has the highest accumulation of radioactivity in tumor was chosen for the tissue distribution and tumor competition on the tumor bearing mice. The GPRPAA(D)A(D)-HYNIC-99Tcm had strong activity distribution in tumor with very low background activities in other tissues

and was quite stable with high radio labeling ratio. GPRPAA(D)A(D)-HYNIC-99 Tcm could become a tracer of tumor angiogenesis.