A thyroid scan is a test to help determine the shape, size, and position of your thyroid.  The test is also used to detect and evaluate nodules (lumps and bumps) in your thyroid.

A thyroid scan can also be used in conjunction with a thyroid uptake to evaluate if the thyroid is overactive (hyperthyroidism) or underactive (hypothyroidism).

Preparation

For a thyroid scan, you may be required to be off any thyroid medications (Synthroid, Eltroxin, Tapazole, etc.) prior to the test.

You will be informed at the time of the booking whether to cease your medications and for how long.

GE Hawkeye Infinia
Equipment used for this test: GE Hawkeye Infinia

Please Inform Your Doctor Or The Technologist If You Are,
 Or Think You Might Be Pregnant Or Breastfeeding.

Procedure

Check-in at the Diagnostic Imaging Department at the Sault Area Hospital for your appointment.

To perform a thyroid scan you will be given a small injection of a radioactive tracer (Technetium-99m Pertechnetate) into a vein.  The tracer will go to your thyroid and be taken into the gland.  A series of images of your thyroid will be taken with our camera showing us how the tracer is distributed throughout your thyroid.  The test typically takes around 20-30 minutes and you shouldn’t feel anything from the injection.

Following your test, there are no restrictions and you will be able to drive as you normally would.  If you are planning on going into the United States of America you will set off the radiation detectors for approximately 2-3 days.  We can provide a letter explaining why you are setting off the detectors however you will still be stopped.

Once your scan is complete it will be examined by a radiologist and a report will be sent to the ordering doctor within a week.  Follow up your test with the ordering physician or your family doctor.

The Injection

The amount of radioactive tracer injected for a thyroid scan is small enough that there are no additional requirements or precautions to protect others from radiation exposure.  The radiation exposure to you is less than a standard chest x-ray.  Most of the injections will be cleared out of your body within 24 hours.

Allergic reactions to the materials used are extremely rare and you shouldn’t feel anything from the radioactive material.

The Camera

A thyroid scan is acquired using a gamma camera, a type of radiation detector that is used to show us how the radioactive tracer is distributed throughout your thyroid.  The gamma camera will have a pinhole camera attachment (looks like a giant cone) on it.  The pinhole camera allows for a magnified view of your thyroid.  Our cameras do not emit radiation or loud noises and are not a hazard to anyone in the vicinity while acquiring.