Imaging Tests for Thyroid Conditions
To identify thyroid cancer, you may need tests with scanning machines that produce images of your body. A radiologist will interpret these images to understand the precise location and size of a tumor.
At Stanford, our imaging technicians specialize in thyroid cancer imaging, providing deep expertise you can trust. Imaging may include:
An ultrasound uses high-frequency sound waves to create images of the thyroid gland, nodules, and surrounding lymph nodes. Ultrasound does not use radiation and is painless. It can provide clearer images of soft tissues like the thyroid gland or nodules that may be present on the thyroid gland.
Ultrasound of the neck can:
- Show greater detail of thyroid abnormalities
- Distinguish between different types of tissues, such as fluid-filled cysts and solid masses
- Help guide a biopsy needle to take a tissue sample and test for cancer
- Look for potential spread of cancer to lymph nodes
The thyroid gland’s job is to absorb iodine and convert it to thyroid hormone. A radioactive iodine uptake test (RAIU) is a nuclear imaging study that helps us measure thyroid function. You will be given an oral or intravenous radiotracer. When it is time for the study to begin, you will be seated and asked to remain still as your doctor moves a wand-like device over your throat. The study is painless.
Magnetic resonance imaging (MRI) uses radio waves and a powerful magnetic field to create detailed, cross-sectional pictures of the thyroid. MRI does not use radiation.
During the diagnostic process, MRI can help us:
- Better evaluate abnormal findings on an ultrasound
- Measure cancer tumors after diagnosis
- Determine whether cancer has spread beyond the thyroid to other areas in the neck
- Surgical planning
After treatment has begun, an MRI can show how well thyroid cancer treatment – surgery, chemotherapy, or radiation therapy – is working by monitoring the size of the tumor to see if it is shrinking.
If you receive a diagnosis of an invasive type of thyroid cancer, you may need a chest X-ray. This test can show your doctor whether the cancer has spread.
A bone scan can rule out whether thyroid cancer has spread to your bones. Also called skeletal scintigraphy, the test uses a small amount of radioactive material to highlight any abnormal tissue, which may indicate cancer. Your doctor may recommend a bone scan if you are diagnosed with an invasive type of thyroid cancer.
PET and CT scans
A positron emission tomography (PET) scan is a nuclear imaging test that uses a small amount of radioactive material to highlight areas of suspicious cells. Computed tomography (CT) scans use X-ray technology to take cross-sectional images of the body. We use these technologies alone or combined, depending on the information we need from the scans.
During treatment for thyroid cancer, our doctors use PET scans alone to:
- Determine whether cancer has spread to the lymph nodes or other parts of the body and, if so, where
- Monitor how well cancer is responding to treatment
- See if cancer has returned after treatment
We rarely use CT scans alone to evaluate cancer in the thyroid. CT is helpful in examining other areas of the body to see if thyroid cancer has spread.
We offer combined PET/CT scanning, which takes both scans at the same time and in the same machine to keep you in the same position. This technique allows us to combine CT images of the body with PET scans that highlight possible areas of cancer.
The combined PET/CT images show the specific locations of any cancer, providing more precise information for treatment. We use PET/CT scans to:
- Stage thyroid cancer
- Check other parts of the body to see if thyroid cancer has spread there
- Monitor cancer’s response to treatment
Current as of: 1/2020