Types of medical imaging: CT scans, MRIs, X-rays, and more

When you visit the doctor, they often begin by asking questions and reviewing your health history. They might also perform simple tests in the exam room. But sometimes, that’s not enough to understand what’s going on inside your body. That’s where medical imaging comes in.

Medical imaging uses special machines to take pictures or videos of the inside of your body. Your doctor uses these images to find out more about your health. Different types of images show different things, like your bones, organs or even blood flow.

Let’s explore some common types of medical imaging and what you can expect with each one.

X-rays

X-rays are probably the most well-known kind of medical imaging. They use a small amount of radiation to take pictures of your bones and some soft tissues.¹

What to expect

You might need to wear a hospital gown or take off jewelry or your glasses.

A trained technician helps you get into the right position. You might stand or lie down, depending on which area needs to be checked. The X-ray machine sends a beam through your body. Some rays pass through, while others bounce back to create an image.²

Why you might get an X-ray

• To check for broken bones
• To look for cavities in your teeth
• To examine your lungs for problems

Computed tomography (CT) scans

A CT scan is like a super-powered X-ray. It takes many pictures of your body from different angles and a computer combines them into a clear, 3D image of your bones, organs and soft tissues.^1,3

What to expect

You might need to wear a hospital gown and take off jewelry or glasses. Sometimes, you get a special dye called contrast material, either by drinking it or through an injection. This helps certain areas show up better.³

You’ll lie on a table that slides into a large, round machine. The machine might make clicking or buzzing sounds, which is normal. The scan usually takes 10 to 30 minutes. The technologist can speak to you from another room and answer your questions.

Why you might get a CT scan

• To check your blood vessels
• To look more closely at the organs in your midsection
• To check small bones that might be hard to see in an X-ray
• To look at or find tumors
• To check for a head or back injury

Fluoroscopy

Fluoroscopy creates a live video of what’s happening inside your body.¹

What to expect

You might need to take off some of your clothes and your jewelry. Sometimes, you’ll drink or receive an injection of contrast material that helps the doctors see things more clearly. You’ll lie on a table while a special X-ray machine takes video images. The length of the test depends on what the doctors need to see.⁴

Why you might get fluoroscopy

Doctors use it to watch things move inside you, like when you swallow or how your blood flows. Sometimes, they use fluoroscopy to place small medical devices inside your body, like a catheter.⁴

3D mammography

Mammograms screen for breast cancer. 3D mammography is a newer, more accurate type of mammogram. It gives doctors a better view, especially if you have dense breast tissue. This is common and just means your breasts have less fat and more tissue.^5,6

What to expect

You’ll remove your top and place one breast at a time on the mammogram machine. The machine gently presses your breast between two plates to spread out the tissue. This may feel uncomfortable, but it’s quick. The machine moves in an arc and takes several images. The technologist will reposition your breast for each picture. The whole test takes about 20 minutes.^7,8

How often to get a mammogram

The National Breast Cancer Foundation suggests women aged 40 and older get a mammogram every year.⁹

PET scans

A PET scan helps doctors see how your organs and tissues are working. For this test, you get a small amount of a special, safe material (called a tracer) by injection. The tracer travels through your body and appears in the scan.¹⁰

What to expect

After getting the tracer, you’ll wait about an hour while it spreads in your body. Then, you lie on a table that slides into a scanning machine. The machine creates images from the tracer in your organs.

The scan time depends on what part of your body needs to be checked. The tracer naturally leaves your body within a few days.¹⁰

Why you might get a PET scan

Doctors use PET scans to check for¹⁰:

• Cancer and if it has spread
• Infections
• Brain and heart conditions

Magnetic resonance imaging (MRI)

An MRI is a special kind of scan that uses strong magnets and radio waves to create pictures of the inside of your body. It’s a great tool for getting very detailed images of any part of your body. Doctors often use it to carefully look at your brain, joints, bones, blood vessels and organs.¹¹

There’s also something called a 3T MRI. This is just a regular MRI, but it uses an even stronger magnet. This helps doctors get extra clear images.¹²

What to expect

During the scan, you’ll lie down on a table that slides into a big, round machine. The machine makes loud banging noises, but that’s normal and just the sound of the magnets working. You may get headphones or earplugs for comfort.

Staying very still is important for clear images. The test usually takes about 30 to 60 minutes. It doesn’t hurt at all, but the space inside can feel tight and noisy.¹²

If you feel anxious or scared in small spaces (claustrophobia), talk to your doctor. You might be able to use an open MRI machine that feels less closed in or explore options to help you relax.¹²

Why you might need an MRI

Your doctor might order an MRI to check for things like¹² :

• Tumors
• Heart problems
• Injuries from sports
• Problems in your brain
• Lung issues
• Bone diseases
• Problems with your eyes or ears
• Spine or back problems

Ultrasound

An ultrasound is a safe way for your doctor to see inside your body. It uses sound waves (not radiation) to create images of your organs and other soft tissues. Ultrasounds are commonly used during pregnancy to check on the development of a baby.¹³

What to expect

You’ll lie down on a table while the person doing the scan, called a sonographer, applies gel to your skin. They move a small device, called a transducer, over the area they need to look at. The gel helps the sound waves travel better.

Most ultrasounds happen on the outside of the body, but sometimes, they might need to use a device that goes inside the body, like when looking at the bladder or vagina.

Why you might need an ultrasound

Doctors might use ultrasounds to¹⁴:

• Check on a baby during pregnancy
• Look at your liver, heart or kidneys
• Help find cysts, tumors or other changes
• Help guide a doctor during a procedure like a biopsy

3D and 4D ultrasound

A 3D ultrasound gives a three-dimensional (3D) picture, so you can see things like a baby’s face in more detail. A 4D ultrasound takes this a step further. It’s like a live video, so you can see movement.¹³

Bone density scan

A bone density scan, sometimes called a DEXA or DXA scan, checks how strong your bones are. It uses a small amount of X-rays to see how much mineral is in your bones. This helps your doctor see if your bones are healthy.¹⁵

What to expect

You lie on a table while a scanner passes over and under you. You can usually keep your clothes on as long as they have no metal, like zippers or snaps. The scan takes about 10 to 30 minutes and is painless.

Why you might need a bone scan

Doctors use this scan to¹⁵:

• Find out if your bones are thin (this is called osteopenia) or weak (this is called osteoporosis)
• See if you might be at risk to break a bone more easily
• To monitor if your bone medicine is working

What is a peripheral DEXA scan?

This is a smaller version of a bone density scan. It checks your bones in places like your wrist, finger or foot. If the scan shows your bones are weak, your doctor might order a full-body bone scan.¹⁵

Takeaway

Each type of scan gives your doctor important information.

Getting a scan can feel scary or confusing, but you’re not alone. Your care team is there to help answer your questions and walk you through your results.

1. Medical X-ray imaging. (2023). https://www.fda.gov/radiation-emitting-products/medical-imaging/medical-x-ray-imaging
2. X-rays. (2024). https://medlineplus.gov/xrays.html
3. American Cancer Society. What is a CT scan? April 29, 2025.
4. Fluoroscopy. (2024). https://medlineplus.gov/lab-tests/fluoroscopy/
5. Breast cancer screening. (2025). https://www.nationalbreastcancer.org/breast-cancer-screening/
6. Diagnostic mammogram. (2025). https://www.nationalbreastcancer.org/diagnostic-mammogram/
7. Mammogram basics. (2022). https://www.cancer.org/cancer/types/breast-cancer/screening-tests-and-early-detection/mammograms/mammogram-basics.html
8. 7 things to know about getting a mammogram. (n.d.). https://www.cancer.org/cancer/types/breast-cancer/mammogram-tips-infographic.html
9. Mammogram. (2025). https://www.nationalbreastcancer.org/mammogram/
10. Facts about nuclear medicine. (2024). https://www.cdc.gov/radiation-health/data-research/facts-stats/nuclear-medicine.html
11. Magnetic resonance imaging (MRI). (2023). https://familydoctor.org/magnetic-resonance-imaging-mri/
12. 3T MRI. (n.d.). https://www.cancer.gov/publications/dictionaries/cancer-terms/def/3t-mri
13. Ultrasound imaging. (2024). https://www.fda.gov/radiation-emitting-products/medical-imaging/ultrasound-imaging
14. Ultrasound. (2023). https://medlineplus.gov/lab-tests/sonogram/
15. Bone density scan. (2024). https://medlineplus.gov/lab-tests/bone-density-scan/