Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) were used as imaging methods.58 An NGR conjugate of a 68Ga chelate with 1,4,7-triazacyclononane-N,N′,N′′-triacetic acid (NOTA), abbreviated as 68Ga-NOTA-G3-NGR (Fig. 3), was tested in imaging of CD13+ HT-1080 cells and CD13- HT-29 human colon adenocarcinoma cells for comparison. Here, ANPEP is linked to colon adenocarcinoma.