This study aims to explore the safety and efficacy of eliminating the PTV expansion margin based on online adaptive stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer (NSCLC) or pulmonary oligometastases. In this study, patients will be stratified according to whether they have primary early-stage NSCLC, then randomly assigned in a 1:1 ratio to the study group or the control group. Patients in the study group will receive online adaptive SBRT (without PTV expansion margin), while patients in the control group will receive conventional standard SBRT. After the completion of treatment, patients will be followed up regularly to assess safety and efficacy.
