The purpose of this study is to evaluate the safety and effectiveness of a specialized surgical technique called "Septum-guided Segmentectomy" for treating early-stage lung cancer located deep within the lung tissue.Standard surgery for lung cancer often involves removing an entire lung lobe (lobectomy), which can significantly reduce a patient's breathing capacity. For small tumors, removing only a segment of the lung (segmentectomy) can preserve more healthy tissue. However, for tumors located deep in the lung, traditional segmentectomy is technically challenging and risks leaving cancer cells behind.In this study, surgeons will use the natural anatomical boundaries-the intersegmental veins and their surrounding thin membranes (septa)-as a guide to precisely remove the target lung segment. This "septum-guided" approach aims to ensure the cancer is completely removed while maximizing the preservation of healthy lung function.Participants will be followed for 3 years after surgery to monitor for cancer recurrence and assess their long-term recovery.