By attaching the transducer to the tip of an endoscope, the transducer may get close to the organs within the body. The pictures acquired are typically more precise and detailed than standard ultrasound imaging due to the near proximity of the EUS transducer to the organ(s) of interest. Endoscopic images are also capable of showing abnormalities not apparent with traditional ultrasound scans. Endoscopic imaging allows for visual inspection of the gastrointestinal (GI) tract without invasive surgery. An endoscopist uses a fiber-optic cable connected to a camera on the end of the tube to view the inner lining of the stomach and intestines. The scope is advanced through the colon in a similar manner using a push button control at the end of the tube to view different areas. An endoscopist can also use tools attached to the end of the scope to collect biopsies from suspicious lesions or insert tubes into the bladder to remove urine samples for testing. Ultrasound imaging uses sound waves to create images of organs inside the body. It is noninvasive and does not involve any type of contact with the patient. The ultrasound image is created by transmitting acoustic signals into the body and recording the time it takes for these signals to be reflected back to the receiver. Different tissues have different amounts of reflectivity which allow doctors to distinguish various organs. Tumors do not reflect sound as well so they show up as dark spots on an ultrasound image.