This study is a multi-center, prospective, randomized controlled clinical trial. The purpose is to compare the difference of indocyanine green fluorescence imaging method and modified inflation-deflation method in identifying intersegmental plane in segmentectomy, and provide high-level evidence for the selection of intersegmental plane identification method in early NSCLC segmental resection.

In patients with early-stage lung cancer, segmentectomy has comparable long-term survival results compared with conventional lobectomy, but patients have a higher postoperative quality of life because more lung tissue is preserved.

Segmentectomy is based on accurate anatomy, and the identification of intersegmental plane is one of the keys to accurate anatomy of segmentectomy.

At present, differential ventilation and differential colorimetry are clinically used to cause the difference between the target segment and the adjacent lung segment to identify intersegmental plane, which both have advantages and disadvantages. Clinical consensus on the best method for intersegmental plane identification has not been formed.

This study is a multi-center, prospective, randomized controlled clinical trial. The study plans to enroll 272 patients with peripheral stage I NSCLC with tumor diameter ≤2cm and consolidation tumor rate <1. Eligible patients will be randomly divided into the experimental group (indocyanine green fluorescence imaging method) or control group (modified inflation-deflation method) at a ratio of 1:1.

This study is expected to compare the difference of indocyanine green fluorescence imaging method and modified inflation-deflation method in identifying intersegmental plane in segmentectomy, and provide high-level evidence for the selection of intersegmental plane identification method in early NSCLC segmentectomy.

Inclusion Criteria:

1. Aged 18 to 80 years old;

2. According to the surgical standards of the Eighth edition of People's Medical Publishing House, patients whose blood pressure was under 160/100mmHg and blood glucose was under 5.6-11.2mmol /L with normal functions of major organs such as heart, lung, liver and kidney before surgery are included. The main criteria are as follows:

   i. Cardiac function examination indicated Goldman index grade 1-2; ii. Pulmonary function examination suggested postoperative predicted FEV1≥40% and DLCO≥40%; iii. Total bilirubin ≤1.5 times the upper limit of normal; iv. Alanine aminotransferase and aspartate aminotransferase ≤2.5 times the upper limit of normal value; v. Creatinine ≤1.25 times the upper limit of normal value and creatinine clearance ≥60ml/min;

3. The center of the lesion is located in the other lobes except the middle lobe, and in the middle and outer third of the lung;

4. The maximum diameter of the tumor was not more than 2cm on TLC(Thin layer CT) scan and the clinical stage was cT1a-1bN0M0(according to AJCC staging criteria, eighth edition);

5. Consolidation tumor rate <1；

6. ECOG PSscore 0-1;

7. All relevant examinations should be completed within 28 days before surgery;

8. Patients who understand the study and have signed informed consent.

Exclusion Criteria:

1. Patient with a history of iodine or indocyanine green allergy;
2. Patient who had received antitumor therapy (radiotherapy, chemotherapy, targeted therapy, immunotherapy) prior to surgery;
3. Patient with a history of other malignancies;
4. Patient with secondary primary cancer at enrollment;
5. Small cell lung cancer;
6. Prior history of unilateral thoracotomy;
7. Woman in pregnant or breastfeeding period;
8. Patient with interstitial pneumonia, pulmonary fibrosis or severe emphysema;
9. An active bacterial or fungal infection that is difficult to control;
10. Severe mental illness;
11. History of severe heart disease , heart failure , myocardial infarction or angina pectoris within the last 6 months;
12. patient that researcher considers inappropriate to participate in this study.