A radiologist is a doctor who specializes in the interpretation of medical images such as MR scans, CT scans, radiographs, nuclear medicine scans, mammograms and sonograms.A radiologic technologist or radiographer is the x-ray tech - the person who takes the x-rays for the radiologist to read.Radiology is the branch of medicine that uses radiation for the diagnosis and treatment of disease. Radiography is the process by which radiographs (x-rays) are made.The radiologist is a doctor so he or she makes a lot more money