[68Ga]pentixafor exhibits high uptake and long retention in CXCR4-expressing tissues (6.16 % ± 1.16 % ID/g, 1 h post-injection (p.i.)and 4.63 % ± 1.54 %, 2 h p.i. in OH1 human small cell lung cancer tumor-bearing mice) and is rapidly cleared from non-target tissue (1.08 % ± 0.27 % in the blood, 1 h p.i.)and renally excreted [7]; the corresponding tumor-to-blood and tumor-to-muscle ratios are substantially higher than those compared to other peptidic CXCR4 imaging agents [8]. The gene discussed is CXCR4; the disease is small cell lung carcinoma.