Not required. Lung CT and chest CT are the same test, just called differently. The scope of the test ranges from the tip of the lung to the angle of the diaphragm, and the physician can choose different windows to observe the image changes according to different diseases. Chest CT is divided into lung window and mediastinal window, which can detect lesions in the lungs and thoracic cavity, esophagus, mediastinum, thoracic bones, breast and other locations, such as pneumonia, emphysema, lung tumors, pleural effusion, etc.; esophageal cancer, esophageal varices; thymoma, lymphoma, neurogenic tumors, etc.; bone fracture and bone tumors; breast lumps and soft tissue lesions. There is no need for a chest CT after a lung CT because they are the same test and the doctor can understand the lesion based on the comparison of the lung window and mediastinal window in the chest CT image.