Whole Body Scan
Another test that checks for the return or spread of thyroid cancer is called a whole body scan (WBS). To prepare for a WBS, you will be asked to swallow a capsule or liquid that contains a very small amount of radioactive iodine (RAI). This will be absorbed by any remaining thyroid cells in your body. You will then be asked to return for the scan in about 48 hours. This involves lying down under a large camera that scans for x-rays being emitted by any remaining radioactive iodine that may have been captured in your body. If any thyroid or thyroid cancer cells are present, they may show up as spots on the x-ray film. However, if only microscopic thyroid cancer cells are present in the body, they are not always visible on the scan.
How can you improve the sensitivity of a WBS?
In order to improve the sensitivity of a WBS, the test must be able to detect even small amounts of thyroid cells. With thyroid stimulating hormone (TSH) in your bloodstream, any thyroid cells that are present in your body will be stimulated to absorb more radioactive iodine, making it more likely that the WBS will detect them.
There are currently two options to increase TSH levels in your bloodstream:
- Stop taking thyroid replacement hormones. This approach enhances the accuracy of the test, however, it will induce hypothyroidism, a condition that can potentially have a negative impact on your daily life. Visit the Hypothyroidism section to learn more.
- Receive Thyrogen®, (thyrotropin alfa for injection), a version of TSH manufactured by biotechnology that is similar to the TSH that your body naturally produces. Thyrogen enhances the accuracy of the WBS test without inducing hypothyroidism because you can continue to take your thyroid hormone therapy. Thyrogen must be prescribed by your doctor. Go to About Thyrogen for more information.
In addition to Tg testing and a whole body scan, doctors may recommend an ultrasound of the neck or other, more sophisticated imaging tests such as a positive emission tomography (PET) scan to see if any cancer has returned or spread. Ultrasound is being used more frequently to detect recurrence of cancer in the lymph glands of the neck.
Download these resources to learn more about thyroid cancer and Thyrogen, including how to manage your Thyrogen treatment.