Fluorescence-navigated thoracoscopic imaging with indocyanine green (ICG) is a novel technique for detection of small pulmonary nodules other than traditional radiography or intraoperative palpation. As a non-targeted fluorescent contrast agent, ICG accumulates in tumors by the enhanced permeability and retention effect (EPR), making the lesions fluoresce under fluorescent imaging. However, the optimal dosage and injection time of ICG are still under exploration. Hence, we perform this study in humans made up of four groups to determine the optimal time and dose.

Inclusion Criteria:

• Peripheral pulmonary solid nodules, with diameter 1-3 cm.
• Suitable for surgery and signed informed consent.

Exclusion Criteria:

• Liver dysfunction.
• Allergic to indocyanine green.
• Can't tolerate thoracoscopic surgery.