Endoscopic ultrasound (EUS) is a diagnostic tool used to evaluate lung and gastrointestinal cancers. Combined with PET/CT scanning, it provides high-resolution images so physicians can confirm the stage of the cancer, explore its exact location, determine the depth of a tumor in the wall of the colon, assess if the cancer has spread to nearby lymph nodes or organs, and determine the optimal course of treatment. Highly trained gastroenterologists perform these procedures.
EUS involves the use of a thin, flexible tube called an endoscope to examine patients. Within the endoscope is an ultrasound transducer, which produces sound waves to create images of the colon. With these detailed images, the extent of the cancer is determined.
EUS can also guide fine-needle biopsies and is a minimally-invasive alternative to surgery when combined with a biopsy.