The tumor-to-background ratio (5.61 ± 0.69) and tumor uptake (4.95 ± 0.67 %ID/g) at 1 h after injection were significantly higher than for the blocking group (1.95 ± 0.17 %ID/g, P < 0.01, t = 8.72), demonstrating the specificity of 68Ga-DOTA-NT-20.3 for NTR1-positive tumors. The gene discussed is NTSR1; the disease is neoplasm.