Ultrasound imaging (sonography) uses high-frequency sound waves to view inside the body. Because ultrasound images are captured in real-time, they can also show movement of the body’s internal organs as well as blood flowing through the blood vessels. Unlike X-ray imaging, there is no ionizing radiation exposure associated with ultrasound imaging.
Ultrasound imaging is a medical tool that can help a physician evaluate, diagnose and treat medical conditions. Common ultrasound imaging procedures include:
- Abdominal ultrasound (to visualize abdominal tissues and organs)
- Bone sonometry (to assess bone fragility)
- Breast ultrasound (to visualize breast tissue)
- Doppler fetal heart rate monitors (to listen to the fetal heart beat)
- Doppler ultrasound (to visualize blood flow through a blood vessel, organs, or other structures)
- Echocardiogram (to view the heart)
- Fetal ultrasound (to view the fetus in pregnancy)
- Ultrasound-guided biopsies (to collect a sample of tissue)
- Ophthalmic ultrasound (to visualize ocular structures
- Ultrasound-guided needle placement (in blood vessels or other tissues of interest)
Ultrasound imaging has been used for over 20 years and has an excellent safety record. It is based on non-ionizing radiation, so it does not have the same risks as X-rays or other types of imaging systems that use ionizing radiation.
Information for Patients including Expectant Mothers
For all medical imaging procedures, the FDA recommends that patients talk to their health care provider to understand the reason for the examination, the medical information that will be obtained, the potential risks, and how the results will be used to manage the medical condition or pregnancy. Because ultrasound is not based on ionizing radiation, it is particularly useful for women of child-bearing age when CT or other imaging methods would otherwise result in exposure to radiation.
Ultrasound is the most widely used medical imaging method for viewing the fetus during pregnancy. Routine examinations are performed to assess and monitor the health status of the fetus and mother. Ultrasound examinations provide parents with a valuable opportunity to view and hear the heartbeat of the fetus, bond with the unborn baby, and capture images to share with family and friends.
In fetal ultrasound, three-dimensional (3D) ultrasound allows the visualization of some facial features and possibly other parts such as fingers and toes of the fetus. Four-dimensional (4D) ultrasound is 3D ultrasound in motion. While ultrasound is generally considered to be safe with very low risks, the risks may increase with unnecessary prolonged exposure to ultrasound energy, or when untrained users operate the device.
Expectant mothers should also be aware of purchasing over-the-counter fetal heartbeat monitoring systems (also called doptones). These devices should only be used by trained health care providers when medically necessary. Use of these devices by untrained persons could expose the fetus to prolonged and unsafe energy levels, or could provide information that is interpreted incorrectly by the user.