A radiologist is a medical doctor who specializes in diagnosing and treating injuries and diseases using medical imaging procedures such as X-rays, computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, positron emission tomography (PET), and ultrasound. They complete at least 13 years of training, including medical school, a four-year residency, and often an additional one- or two-year fellowship of very specialized training. Radiologists are experts in interpreting a multitude of imaging exams, understanding how to obtain the best quality imaging exam, and acting as expert consultants to referring physicians by aiding them in choosing the proper exam and interpreting the resulting medical images to direct patient care