Medical imaging technology is rapidly progressing. Positron emission tomography (PET) has played major role in the staging and choice of treatment modality in lung cancer patients. Magnetic resonance imaging (MRI) is now routinely used for mediastinal tumors and the use of diffusion-weighted images (DWI) may help in the diagnosis of malignancies including lung cancers. The benefits of medical imaging technology are not limited to diagnostics, and include simulation or navigation for complex lung resection and other procedures. Multidetector row computed tomography (MDCT) shortens imaging time to obtain detailed and precise volume data, which improves diagnosis of small-sized lung cancers. 3-dimensional reconstruction of the volume data allows the safe performance of thoracoscopic surgery. For lung lobectomy, identification of the branching structures, diameter, and length of the arteries is useful in selecting the procedure for blood vessel treatment. For lung segmentectomy, visualization of venous branches in the affected segments and intersegmental veins has facilitated the preoperative determination of the anatomical intersegmental plane. Therefore, the application of medical imaging technology is useful in general thoracic surgery.