In addition, the first PRRT with [<sup>177</sup>Lu]Lu-DOTA-MGS5 was conducted in a patient with extensive disease SCLC (ED-SCLC) after confirming CCK2R-positive uptake in [<sup>68</sup>Ga]Ga-DOTA-MGS5 PET/CT. Here, CCKBR is linked to small cell lung carcinoma.