What are the Most Common Imaging Tests?
Here are some of the most frequently used imaging tests in medical care.
X-Ray
X-rays are quick tests that use small amounts of radiation to create black-and-white images of the body’s internal structures. Providers commonly use them to look at bones and joints to diagnose fractures. But X-rays can help detect certain infections and diseases, too. During an X-ray, you will stay still while a machine sends small, invisible radiation beams through your body. You will not see or feel the beams, but structures in your body absorb them in different ways. Solid objects, like bones, easily absorb radiation and appear white in the final image. Softer tissues, such as muscles and organs, absorb less and show up as shades of gray. This contrast helps your provider get a clearer view of injuries or abnormalities.
CT (Computed Tomography) Scan
A CT scan takes X-rays to the next level. Instead of just one image, it combines multiple X-ray images from different angles to create a cross-sectional view of your body. Cross-sectional images show your body in thin layers, like looking at one slice in a loaf of bread. When you put all the slices together, they create a detailed 3D view. CT scans can help diagnose a wide range of conditions, including cancer, heart disease, injuries and infections. They are also helpful when planning treatments like surgery or radiation therapy. During the procedure, you will lie still on a table that slides into a donut-shaped machine. As it rotates, the machine captures a series of images of your body. The whole process takes about 30 minutes.
MRI (Magnetic Resonance Imaging)
MRI scans use powerful magnets and radio waves to produce highly detailed images of your organs, tissues and bones. Providers often use MRIs to examine the brain and spinal cord. But they’re also helpful for spotting tumors and other issues throughout the body. You will lay on a table that moves into a large, tube-shaped scanner. Inside, the machine creates a magnetic field and sends radio waves into your body. These elements work together with the hydrogen atoms in your body to create clear, cross-sectional images. The scan can last from 30 to 90 minutes, depending on what your provider needs to see. MRI machines can be loud, so you may hear knocking or thumping sounds during the scan. You will usually be given earplugs or headphones to make it more comfortable.
Ultrasound
Ultrasounds use high-frequency sound waves to create real-time pictures — called sonograms — of the inside of your body. Most people think of pregnancy when they hear “ultrasound,” but we use these tests for much more. Providers rely on them to diagnose unexplained pain, lumps or organ issues. During the test, a technician applies a special gel to your skin to help the sound waves travel. Then, they move a small handheld device called a transducer over the examination area. The transducer sends sound waves into your body, which bounce off internal structures and return as echoes. A computer then translates these echoes into moving pictures on a screen.
PET (Positron Emission Tomography) Scan
A PET scan is a powerful test that shows how your organs and tissues are working — not just what they look like. It is especially useful for detecting cancer, determining if it has spread and assessing how well treatments are working. PET scans can also help diagnose certain heart and brain conditions. Before the scan, you will get a small injection of a radioactive tracer, usually a form of sugar. Active cells, like cancer cells, absorb more of this sugar, which makes them stand out in the images. You will then lie on a table that slides into a donut-shaped scanner, which detects the tracer’s radiation to create detailed pictures. The test typically lasts 30 minutes to an hour.
Are Diagnostic Imaging Tests Safe?
Yes, diagnostic imaging tests are generally very safe. While some tests use radiation, the amount is typically low and carefully controlled. Other imaging methods, like MRI and ultrasound, use no radiation. “Imaging helps us make informed decisions without guessing,” says Dr. Flowers, “And we always balance the need for clarity with a commitment to safety.” Your doctor will only recommend a scan when it is medically necessary. They will always use the lowest radiation dose possible to get the information they need. If you have questions or concerns, do not hesitate to ask. Your care team can walk you through the benefits and any potential risks of your test, so you feel confident moving forward.
Find Care at Catholic Health
To make an appointment for an imaging test at a Catholic Health Radiology Imaging Location call (631)465-6880.
Find a Catholic Health doctor near you. Or call 866-MY-LI-DOC (866-695-4362).