Imaging Tests and Radiation

Imaging tests can help your doctor understand your medical condition. But how do these tests work?

X-Ray
X-rays pass electromagnetic radiation beams through the body. Soft tissue like skin and organs can't absorb the rays, so those show up as gray on imaging. Dense materials like bones do, so those images appear white on imaging. Generally, these tests are performed on the abdomen, chest or bones to look for fractures, cancers, decay, infection, arthritis, blockages and even digestive problems.

CT Scan
A computed tomography (CT) scan is a type of X-ray but produces 360-degree views of the body in greater detail than a conventional X-ray. According to Johns Hopkins, it can detect blood clots, organ injuries and bone fractures that aren't visible on X-rays. CT scans are one of the fastest and most accurate tools for scanning the chest, abdomen and pelvis.

Ultrasound
Ultrasounds are frequently used to create pictures of unborn babies. Ultrasound uses high-frequency sound waves that bounce back and create images. However, this test is also used to view the kidneys, liver and soft tissues in the body. Surgeons can also use ultrasound imaging to guide procedures, such as biopsies, and see inside the heart.

MRI
Magnetic resonance imaging (MRI) uses a large magnet and radio waves to see inside areas such as your joints, heart, blood vessels and brain. As magnetic and radio waves bounce off fat and water molecules in the body, a receiver produces images that allow doctors to easily see the difference between healthy tissue and a problem—such as a tumor. Other ailments that might require an MRI are nerve compression, spinal injuries or torn ligaments. However, because the magnetic field of an MRI is so strong, it's important to tell your doctor about any metal implants or pieces of metal in your body.

Radiation Concerns
While you might be worried about radiation exposure, the Mayo Clinic says no radiation remains in your body after a radiographic, CT, ultrasound or MRI. For tests like x-rays and mammograms, a person is exposed to the same amount of radiation they'd encounter naturally in a week or two.

If you still have concerns about radiation, talk to your provider.

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