Certain medical procedures can also injure the airways; these include tracheal intubation, bronchoscopy, and tracheotomy. Additional tests include X-ray computed tomography, bronchoscopy or lung biopsy. Biopsy is usually performed via bronchoscopy or CT-guided biopsy. Complications from fiberoptic bronchoscopy remain extremely low. The diagnosis is confirmed by biopsy which is usually performed by bronchoscopy or CT-guidance. Flexible bronchoscopy can also be performed on intubated patients, such as patients in intensive care. These drawbacks limit the use of fiberoptic bronchoscopy somewhat in urgent and emergency situations. Rigid bronchoscopy is performed under general anesthesia. Transtracheal or transbronchial (via bronchoscopy) aspirates can also be cultured. To make sure the lung is satisfactory before transplanting the other a bronchoscopy is performed. Casts can be removed mechanically by bronchoscopy or physical therapy. The most common complication from rigid bronchoscopy is damage to the patient's teeth. Following these function tests a CT scan or bronchoscopy will be ordered. Laser photocoagulation can be used to stop bleeding during bronchoscopy. Rigid bronchoscopy is used for retrieving foreign objects.