How is a "radiologist" different than a "radiation oncologist"?

How is a "radiologist" different than a "radiation oncologist"?

A radiologist is a physician who specializes in reading imaging tests. So mammography, ultrasound, x-ray, CT scan, MRI: a radiologist reads those. A radiation oncologist is a specialist who focuses on providing radiation to – in general – cancer, and helping to treat cancer. Radiologists and radiation oncologists are both MD's, and they've gone through medical school, as well as a residency specializing in either radiology or radiation oncology.