What Is a Radiologist?

Medically Reviewed by Sabrina Felson, MD on September 15, 2021
4 min read

Radiologists are doctors who take pictures of the inside of your body to help diagnose and treat illnesses. These medical images are taken in different ways, including:

Radiologists have 9 or more years of medical education, including at least 4 years of on-the-job training called residency. They may spend another 1 or 2 years on top of that on a specialized fellowship in such areas as interventional  radiology or breast imaging. These doctors are required to keep up with medical advances in radiology in order to keep their certification.

A radiologist will be involved in your care if your doctor needs assistance with imaging or certain specialized treatments.

Some common reasons you might need a radiologist are:

  • Broken bone
  • Torn muscle
  • Pregnancy
  • Screening for cancer or tumors
  • Blocked arteries or other vessels
  • Foreign objects in the body
  • Trauma and accidents
  • Infections


Depending on your procedure, your appointment can take just minutes or last 2 hours or more. You usually don’t need to prepare for your appointment. But some tests may require you to avoid certain foods, medications, and drinks beforehand.

Always tell the radiology office if you’re pregnant or trying to have a baby. X-rays and CT scans use low-dose radiation. Your doctor may want to use a different imaging test if possible in order to avoid exposing your baby to any possible harm.

X-ray. You’ve probably had your teeth X-rayed at your dentist’s. A medical X-ray is just as simple. You lie or stand and position yourself as asked. It’s over in minutes. You may get an X-ray after a car accident, or if you have trouble breathing, pneumonia, lung cancer, or other conditions.

CT scan. This gives a more detailed look at your body than X-rays. Beams of X-rays circle your body to view your organs, bones, and other parts from multiple angles. You’ll lie still on a padded table as it slides into a short, open-ended tunnel. Your radiologist may use it to check a complicated bone fracture, internal bleeding, infections, tumor size, and other reasons. For some CT scans, you may need to take a contrasting substance by mouth or IV to make the image clearer.

Ultrasound. It’s best known for taking pictures of babies in their mother’s womb. Ultrasounds use sound waves to help pinpoint heart damage, swelling, infection, tumors, and other things.

MRI. Instead of radiation, MRIs use radio waves and a magnetic field to peek inside your body. They allow your radiologist to better see soft tissue behind or inside your bones. It’s especially useful for scanning your brain and spinal cord, or for torn ligaments or tumors. Let your doctor know if you could be pregnant or if you have any metal parts or electronic implants, such as:

Your technician may be able to adjust the procedure so that you can still get an MRI.

PET scan. Positron emission tomography (PET) is a type of nuclear medicine imaging. It uses a small bit of radioactive material to examine the inside of your body at the level of molecules. So PET scans may detect cancer or problems with your heart, brain, nerves, and elsewhere before other imaging tests can. Usually, you’ll need to stop eating and drinking anything other than water several hours before your procedure.

Most radiologists help diagnose health problems. But others focus more on treatments.

Interventional radiologist. These doctors guide instruments through a small cut on your body where you need treatment. They might use a:

  • Needle to drain fluid
  • Tube for drainage or to deliver drugs or nutrition
  • Laser to remove fibroids or other growths
  • Stent, or tiny tube, to support a blood vessel
  • Balloon to clear out an artery (angioplasty)

Interventional radiologists sometimes take out tissue samples for examination with a microscope (biopsy) for cancer.

Radiation oncologist. They specialize in treating cancer. They use energy beams or radioactive particles to attack cancer cells, while taking care to limit damaging healthy ones. Your radiation oncologist will work closely with all other members of your cancer care team.