The Role of CT Scans, MRIs, X-Rays and Ultrasounds in Cancer Treatment

Imaging tests go by many names. They are sometimes called imaging studies or by their type, such as X-rays, CT scans, MRIs or ultrasounds. Whatever type of imaging test you undergo, these tests help doctors look for cancer, determine its spread and evaluate whether your treatment is working. Of course, imaging tests also provide doctors with a view inside your body to find other diseases, broken bones, torn tissues or other injuries.

Imaging tests work by sending energy through your body. Energy types used in imaging include X-rays, sound waves, magnetic fields or radioactive particles. When these energies contact tissues, the tissues change the patterns of the energy to create an image.

Imaging Tests in Cancer

Imaging tests provide important information for cancer treatment, including:

• Looking for cancer in early stages, before it has spread and provides symptoms, as part of early detection or cancer screening
• Looking for tumors, masses or lumps when someone has symptoms
• Determining whether symptoms are from cancer or another disease or injury
• Predicting whether a tumor is likely cancerous or benign
• Determining whether a biopsy is necessary
• Showing tumor location, even deep in the body
• Finding the stage of cancer, determining whether and how far the cancer has spread
• Planning treatment, such as where to aim radiation beams
• Showing whether tumors respond to treatment
• Finding out if the cancer has recurred after treatment

Although imaging tests provide a great deal of information for cancer treatment and related doctors, these tests are only part of your cancer care. You also need a complete medical history, physical exam, blood work and other lab tests.

Imaging tests often take place before treatment begins. These images form a baseline for tracking tumor response to treatment over time. Doctors compare these baseline studies with future images to determine whether your treatment is effective or ineffective.

Imaging Tests Have Limits

Imaging tests play a very critical role in cancer treatment. But they have limitations, such as in showing whether a change is cancer or something else. These tests show large groups of cancer cells but cannot find cancer before it is visually detectable. In essence, you have millions of cancer cells in your body before a tumor is visible on an imaging study. This is why you still gain treatment for your cancer, even when there is no visible cancer on your imaging tests.

Imaging Test Types

There are many different types of imaging scans available for gaining an inside view of your body. These include:

• Mammography
• Breast MRI
• Computed tomography (CT) scan
• Magnetic resonance imaging (MRI) scan
• X-rays
• Nuclear medicine scans
• Ultrasound

Which tests your doctor orders depends on several factors. These include:

• Tumor location and size
• Whether you need a tissue sample for biopsy
• Age
• Gender
• Overall wellness
• Risks, side effects and expectations
• Personal preference
• Cost

When you have questions about your imaging tests or other aspects of your cancer treatment, ask your doctor or other members of your treatment team. Doctors will take the time to help you understand why you need the test, what it could find, pros and cons of the test and other options available to you.