A thyroid shield is a small piece of leaded vinyl worn around the neck to protect the thyroid gland from radiation exposure.
The thyroid gland is in your neck and affects your growth and development.
Some members of staff or patients wear a thyroid shield during some medical imaging scans to decrease the amount of radiation to the thyroid gland.
Having a mammogram
We do not recommend wearing a thyroid shield when having a mammogram.
The thyroid gland is not exposed to the direct X-ray beam. Only the breast being examined will receive an intentional dose of radiation during the X-ray.
Wearing a thyroid shield during a mammogram might interfere with your position and hide your breast on the X-ray. This can mean that the image is not as helpful to the doctors, and you might need to have the mammogram repeated. This would mean an unnecessary increase in radiation to your breast which would be a bigger risk than if you didn’t wear a thyroid shield at all. It could also cause you more worry and stress.
Mammography machines are designed to make sure you are safe. They have radiation shields inside, which stop radiation reaching other parts of your body.
Any radiation to the uterus is so low that it is unmeasurable, so wearing a shield to cover your tummy (abdomen) is not necessary.
Resource number: 4560/VER4
Published date: July 2023
Review date: July 2026