PET-CT examination is generally not recommended 20 days after lung adenocarcinoma surgery, because it may lead to misdiagnosis, and the function of evaluating the development of lung adenocarcinoma disease is not significant. PET-CT examination belongs to the imaging examination with relatively high resolution, through which the benign or malignant nature of lung tumors and the extent of spread of lesions in patients with lung adenocarcinoma can be distinguished, so that the clinical staging of patients with lung adenocarcinoma can be more accurately assessed. However, for patients 20 days after lung adenocarcinoma surgery, due to the inflammatory reaction in the surgical area, which may cause local metabolic increase in imaging, if PET-CT is performed at this time, it may be difficult to distinguish benign lesions, such as inflammatory hyperplasia, from the postoperative progression of lung cancer lesions.