After a diagnosis of head and neck cancer, you will likely need more tests. These tests help your doctors learn more about the cancer. They can help show if it has grown into nearby tissues or spread to other parts of the body. The test results help your doctors decide the best ways to treat the cancer. If you have any questions about these or other tests, be sure to talk with your health care team.

Some of the tests used after diagnosis include:

• CT scan
• PET scan or PET/CT
• MRI
• Ultrasound
• Panoramic dental X-ray. This is also called Panorex.
• Modified barium swallow. This is also called a video fluoroscopic swallowing exam (VFSE).

• CT scan. In this test, a series of X-rays is used to get pictures of the inside of your body from many angles. A computer then combines these images to make a detailed 3-D picture of your insides. CT scans can be used to find out the size of the tumor, exactly where it is, and if it has spread to nearby tissues or lymph nodes. You may be given a contrast material before the test to give more detail to the pictures. The contrast is given by a shot (injection) into your vein, or by a pill or liquid to swallow. The CT scan may be done to look at the head, neck structures, chest, and lymph nodes.
• PET scan. A PET scan looks at your entire body. A sugar solution that contains a mildly radioactive material (radiotracer) is put into your blood through a vein in your hand or arm. Cancer cells use the sugar faster than other cells, so the radioactive material will collect in them. Then a machine takes pictures of your whole body. The places where the solution collects show up as "hot spots" on the scan. Cancer cells are more active and take up more glucose than normal cells. They show up brighter. A PET scan is often combined with a CT scan and done at the same time on one machine (called a PET-CT scan). This allows areas that show up on the PET scan to be compared to the more detailed images of the CT scan. This test is very good for looking for cancer that has spread from where it first started.
• MRI. This test uses strong magnets and radio waves to make detailed pictures of the inside of your body on a computer. It's a lot like a CT scan, but it doesn't use X-rays. This test may be used to look for cancer that's spread to the neck. Gadolinium is a contrast material that may be injected into a vein before the scan. Your doctor may choose MRI over a CT scan in some instances, such as when you have cranial nerve symptoms.
• Ultrasound. This test uses sound waves to make images of the inside of your body. It may be used to look for swollen lymph nodes in your neck, which can be a sign of cancer spread. It can also be used to look for cancer that may have spread to the liver.
• Panoramic dental X-ray. This test is a rotating X-ray of the lower and upper jawbones to check if cancer has grown into the jawbone or to check your teeth before treatment.
• Modified barium swallow. Also called video fluoroscopic swallowing exam (VFSE), this is a special test to look at how well you can swallow different foods and liquids effectively and safely. The barium is mixed with foods and liquids. When you swallow, the barium allows pictures to be seen on an X-ray. Fluoroscopy converts X-rays into video images.

Talk with your doctor about which tests you'll have. Make sure to get ready for the tests as instructed. Be sure you know what the test will be like and why it's being done. Ask questions and talk about any concerns you have.