Imaging scans are an important tool in helping clinicians diagnose and manage mesothelioma. These scans include:
- CT scans
- PET scans
These tools help doctors to actually see tumors and other abnormal growths inside a patient’s body.
When patients experience symptoms associated with mesothelioma, doctors often order a scan as one part of their work-up. The results of the scan can help doctors figure out what is causing the symptoms. A scan by itself cannot diagnose mesothelioma, but it is an important tool towards arriving at the correct diagnosis.
X-rays for Mesothelioma
X-ray is the oldest and most basic type of imaging. X-ray’s produce a flat, two-dimensional image so its capacity as a helpful diagnostic tool is limited. Nevertheless, some physicians use it as a start. If an abnormality is seen, such as a mesothelioma tumor, more accurate and sophisticated scans can then be ordered like those described below.
X-rays work be emitting electromagnetic radiation. The radiation is focused on a particular body part and a photographic film is placed on the opposite side. The rays pass through less dense tissue more easily and create an image that is dependent on what the rays encountered while traveling through the body. For example, standard X-rays portray healthy lungs as black. However, when a tumor is present on or near the lungs (such as on the pleural lining), doctors may see an opaque white area.
CT Scans for Mesothelioma
We have all heard of CT or CAT scans. These are actually computed tomography scans which is a type of X-ray. In fact, CT scans are just a more sophisticated use of X-ray technology. CT’s take many X-rays from different planes or cross-sections. Because there are so many “slices” taken at about the same time, these images can be reconstructed by a computer to create a three dimensional representation of what is inside the body. As a result, CT’s are a very useful tool when doctors are trying to see if there are any masses or tumors present such as mesothelioma, and the location and size of any abnormal growths.
Often, contrast material is used to help make a CT scan as accurate as possible. Contrast materials may also be called contrast agents or contrast media and are used to improve pictures of the inside of the body. Contrast materials are basically dyes that temporarily discolor internal organs and change the way x-rays or other imaging tools interact with the body.
By improving the visibility of specific organs or tissues, contrast materials help physicians diagnose mesothelioma and other medical conditions. Contrast materials enter the body by being swallowed, injected into a blood vessel, or administered by enema. There are several types of contrast materials including iodine-based and barium-sulfate compounds. When these contrast materials are present in a specific area of the body, they block or limit the ability of x-rays to pass through. As a result, blood vessels, organs and other tissue that contain the dyes change their appearance on x-ray or CT images.
Many doctors believe that CT’s are the best imaging technology for scans of the chest and abdomen, the most common location of mesothelioma tumors. In addition to finding potential tumors, CT scans can also help doctors perform staging by determining if cancer has spread to lymph nodes, nearby tissues, or distant organs.
MRI Scans for Mesothelioma
Unlike X-rays and CT’s, magnetic resonance imaging (MRI) scans use a completely different type of radiation to develop images of the inside of the body to see mesothelioma and other cancers.
MRI’s work on an atomic scale by temporarily realigning the protons in the water molecules in your body. An MRI applies a very strong magnetic field (about a thousand times the strength of a typical refrigerator magnet), to change the spin of protons. The scanner also produces a radio frequency that creates a varying magnetic field. The protons absorb the energy from the field. When the field is turned off, the protons gradually return to their normal spin. The return process produces a signal that can be made into an image.
What’s amazing is that the protons in different body tissues return to their normal spins at different rates, so the scanner can distinguish among tissues including tumors. In fact, the computer can differentiate between tissues in the body and assign them various colors. Doctors get a clear image of the interior of the body, which can help locate mesothelioma earlier than with X-rays and CT scans.
A positron emission tomography (PET) scan is another technology that allows your doctor to check for diseases in your body like mesothelioma. The scan uses a special kind of dye that has radioactive tracers. Your organs and tissues absorb the tracer and when highlighted under a PET scanner, the tracers help your doctor see how well your organs and tissues are working. The PET scan can measure blood flow, oxygen use, glucose metabolism (how your body uses sugar), and much more. Because cancer cells often have a higher metabolism than normal cells, a PET scan can be useful in detecting mesothelioma and other tumors.
Unlike other imaging tests, such as CT or MRI, PET scans show problems at the cellular level. This allows your doctor to see how the cancer metabolizes, and whether it has spread, or metastasized, to new areas. PET scans can also show how a tumor is responding to chemotherapy.
Before the scan, the tracers may be delivered intravenously or through a solution you can drink. Your body needs time to absorb the tracers, so you will usually wait about an hour before the scan begins.
These are some of the amazing technologies that clinicians have to help diagnose mesothelioma and other cancers and diseases.