Both radiologists and radiology technologists work in a clinical or hospital setting, and are both health-care professionals.
A radiologist is a physician that will interpret diagnostic tests and prescribe a course of treatment for the patient. They begin their education with a bachelor's degree, then attend medical school. After a two year internship, they take a residency in radiology for four to seven years.
A radiologic technologist is the person performing the imaging tests on the patients (CT scans, MRI's, x-rays, and ultrasounds), who then hands them over to the radiologist for interpretation. The technologist needs to have earned either an associate's or a bachelor's degree before practicing, and must be licensed.