Tests that examine the mouth and throat are used to help detect (find), diagnose, and stage oropharyngeal cancer. The following tests and procedures may be used:         -   Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as swollen lymph nodes in the neck or anything else that seems unusual. The medical doctor or dentist does a complete exam of the mouth and neck and looks under the tongue and down the throat with a small, long-handled mirror to check for abnormal areas. An exam of the eyes may be done to check for vision problems that are caused by nerves in the head and neck. A history of the patients health habits and past illnesses and treatments will also be taken.    -   PET-CT scan : A procedure that combines the pictures from a positron emission tomography (PET) scan and a computed tomography (CT) scan. The PET and CT scans are done at the same time with the same machine. The combined scans give more detailed pictures of areas inside the body than either scan gives by itself. A PET-CT scan may be used to help diagnose disease, such as cancer, plan treatment, or find out how well treatment is working.               -  CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the head and neck, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye is 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.       -  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.             -   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).    -   Biopsy : The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. A fine-needle biopsy is usually done to remove a sample of tissue using a thin needle. The following procedures may be used to remove samples of cells or tissue:               -  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 or nose. An endoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove abnormal tissue or lymph node samples, which are checked under a microscope for signs of disease. The nose, throat, back of the tongue, esophagus, stomach, larynx, windpipe, and large airways will be checked. The type of endoscopy is named for the part of the body that is being examined. For example, pharyngoscopy is an exam to check the pharynx.       -  Laryngoscopy : A procedure in which the doctor checks the larynx with a mirror or with a laryngoscope. A laryngoscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove abnormal tissue or lymph node samples, which are checked under a microscope for signs of disease.          If cancer is found, the following test may be done to study the cancer cells:               -  HPV test (human papillomavirus test): A laboratory test used to check the sample of tissue for certain types of HPV infection. This test is done because oropharyngeal cancer can be caused by HPV.