This study demonstrates that 99mTc-labeled anti-PD-L1-sdAb SPECT/CT using 99mTc-NM-01 is a safe diagnostic procedure, delivering a tolerable radiation dose and presenting favorable biodistribution and image characteristics correlating with PD-L1 immunohistochemistry results in patients with NSCLC. Here, CD274 is linked to non-small cell lung carcinoma.