18F-FDG PET/CT Radiomics Models for Precision Diagnosis and Prognosis in NSCLC

Inclusion Criteria: * Age \>= 18 years. * Underwent standard whole-body 18F-FDG PET/CT scan within 30 days before surgery. * Histopathologically confirmed Non-Small Cell Lung Cancer (NSCLC) with clear histological subtyping and complete postoperative TNM staging. * Primary tumor SUVmax \> 2.5 and maximum diameter \> 1.0 cm on CT. * Complete clinical, pathological, and imaging data available. * (For Gene Sub-study) Known EGFR gene mutation status. * (For Prognosis Sub-study) Complete follow-up data available (minimum 12 months or until endpoint event). Exclusion Criteria: * History of other malignancies. * Received any anti-tumor treatment (chemotherapy, radiotherapy, targeted therapy, immunotherapy) prior to PET/CT. * Severe image artifacts or indistinct tumor boundaries affecting ROI delineation. * Missing key clinical or pathological data. * Baseline PET/CT evaluated recurrent or metastatic tumors instead of primary NSCLC. * Extremely short life expectancy due to severe comorbidities.