Americans concerned about thyroid cancer development from mammography

Some Americans have expressed concern, due to an erroneous media report, that the small amount of radiation a patient receives from a mammogram may significantly increase the likelihood of developing thyroid cancer. This concern simply is not supported in scientific literature.

The radiation dose to the thyroid from a mammogram is extremely low. The thyroid is not exposed to the direct X-ray beam used to image the breast and receives only a tiny amount of scattered X-rays (less than 0.005 milligray). This is equivalent to only 30 minutes of natural background radiation received by all Americans from natural sources.

For annual screening mammography from ages 40-80, the cancer risk from this tiny amount of radiation scattered to the thyroid is incredibly small (less than 1 in 17.1 million women screened). This minute risk should be balanced with the fact that thyroid shield usage could interfere with optimal positioning and could result in artifacts - shadows that might appear on the mammography image. Both of these factors could reduce the quality of the image and interfere with diagnosis. Therefore, use of a thyroid shield during mammography is not recommended.

Patients are urged not to put off or forego necessary breast imaging care based on this erroneous media report.