Tests that examine the mouth and throat are used to detect (find), diagnose, and stage lip and oral cavity cancer. The following tests and procedures may be used:         -   Physical exam of the lips and oral cavity: An exam to check the lips and oral cavity for abnormal areas. The medical doctor or dentist will feel the entire inside of the mouth with a gloved finger and examine the oral cavity with a small long-handled mirror and lights. This will include checking the insides of the cheeks and lips; the gums; the roof and floor of the mouth; and the top, bottom, and sides of the tongue. The neck will be felt for swollen lymph nodes. A history of the patients health habits and past illnesses and medical and dental treatments will also be taken.    -   Endoscopy : A procedure to look at organs and tissues inside the body to check for abnormal areas. An endoscope is inserted through an incision (cut) in the skin or opening in the body, such as the mouth. An endoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue or lymph node samples, which are checked under a microscope for signs of disease.     -   Biopsy : The removal of cells or tissues so they can be viewed under a microscope by a pathologist. If leukoplakia is found, cells taken from the patches are also checked under the microscope for signs of cancer.     -  Exfoliative cytology : A procedure to collect cells from the lip or oral cavity. A piece of cotton, a brush, or a small wooden stick is used to gently scrape cells from the lips, tongue, mouth, or throat. The cells are viewed under a microscope to find out if they are abnormal.    -   MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).     -   CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.    -   Barium swallow : A series of x-rays of the esophagus and stomach. The patient drinks a liquid that contains barium (a silver-white metallic compound). The liquid coats the esophagus and x-rays are taken. This procedure is also called an upper GI series.     -   PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.     -   Bone scan : A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner.