After a diagnosis of mesothelioma, you'll likely need more tests. These tests help your health care team learn more about the cancer and your overall health. The results help your doctors decide the best ways to treat the cancer. For instance, scans can show if it has grown into nearby areas or spread to other parts of your body. This helps your doctor figure out if surgery may be a choice. If you have any questions about these or other tests, talk with your health care team.

The tests you may have include:

• CT scan
• MRI
• PET scan
• Mediastinoscopy or other staging surgeries

During a CT scan , X-rays are used to scan part of your body to create detailed 3-D pictures of your insides. You may have this done on your chest or belly (abdomen). These pictures help your doctor see where the cancer is. They can also show if it has spread to nearby organs or lymph nodes, or to other parts of your body.

To have the test, you lie still on a narrow table as it slowly slides through the center of the doughnut-shaped CT scanner. A computer uses many X-rays to create pictures. A CT scan doesn't hurt. You may be asked to hold your breath a few times during the scan. Often, an I.V. contrast-agent (contrast dye) is put into a vein for the scan. This helps details show up better. The I.V. contrast and contrast taken by mouth will slowly pass through your body and exit through your urine or bowel movements.

An MRI uses powerful magnets, radio waves, and a computer to create very detailed pictures of the inside of your body. An MRI is sometimes used to show exactly how much and where the cancer is. This can help tell if surgery might be a choice.

An MRI is not painful. It can take up to an hour to do. Often an I.V. contrast agent called gadolinium will be put into a vein before getting the scan. During the scan, you'll need to lie still on a narrow table that slides into a long, narrow tube. This makes some people feel claustrophobic. If you've had problems with enclosed spaces in the past, tell your doctor before the MRI. You may be given a sedative medicine to help you stay calm during the test. If you get a sedative, you'll need to allow for time after the test for its effect to wear off. Newer, more open MRI machines can sometimes be used instead. But the images may not be as sharp. The equipment makes loud banging noises during the scan. You can ask for earplugs if you think the noise will bother you.

Because the test uses powerful magnets, you won't be allowed to have anything metal in the room. Even eyeglasses and ballpoint pens can be dangerous when the magnets are turned on. Be sure to tell your doctors if you have any kind of metal implant in your body to be sure an MRI is safe for you.

This test may be used to look for spread of the cancer to lymph nodes or to other parts of your body. A PET scan can also be helpful if your doctor thinks the cancer may have spread but doesn't know where. Because it scans your whole body, a PET scan might be done instead of doing multiple X-rays of different parts of your body. The picture isn't as detailed as a CT scan. But it can be done along with a CT scan to look for cancer.

For this test, a mildly radioactive sugar (radiotracer) is put into a vein before the scan. Cancer cells absorb more of this sugar than normal cells. To have the scan, you'll need to lie still on a table as it slowly slides through the doughnut-shaped PET scanner. This machine takes pictures that show where the sugar has collected in your body. These spots might be cancer. A PET scan is painless.

Some imaging centers use a PET/CT scanner machine. This machine does a PET and CT scan at the same time. The doctor can compare high radioactive areas on the PET scan with more detailed pictures on the CT scan.

Imaging tests can help show the extent of the cancer. But they might not always show all of the cancer. Surgery is often the best way to treat mesothelioma, if it can be done. But this is a major surgery. So it's important to know ahead of time if all of the cancer can be removed.

If your doctor thinks surgery might be a choice, a less complex, staging surgery might be done first to help be sure. These surgeries use thin, lighted tubes called scopes to look inside your body. This allows your doctor to look for areas of cancer that imaging tests might have missed. It's not done to treat the cancer.

A mediastinoscopy is an example of a staging surgery. To do it, a thin, tube with a light and lens at the end is put into your chest through a small cut in the skin above your breastbone. This tube is called a mediastinoscope. It's slid down behind your breastbone to see organs, tissues, and lymph nodes there. A staging laparoscopy is another example. In this test, a small, lighted tube with a tiny camera on the end (called a laparoscope) is put in through a cut in the skin over your belly (abdomen). This is done to look at the lining of the inner part of your belly and the lining that covers your intestines and other organs.

If your doctor sees changes that might be cancer, tools can be used through the scope to take out tiny pieces of tissue. These are sent to a lab to be tested. (This is called a biopsy.)

Your doctor will talk with you about which tests you'll have. Make sure to get ready for the tests as instructed. Ask questions and talk about any concerns you have.