Medical imaging professionals are the healthcare workers who create images which aid in disease diagnosis. In general, medical imaging professionals specialize by a particular type of technology. For example, ultrasound technicians use ultrasound machines and sound waves to develop images of tissues and organs; x-ray technicians use radiation to provide images of our bones. Radiology technologists are often trained in several different techniques, including mammography, CT, and MRI scans, although they may specialize in a particular technology. As the sophistication of medical imaging has increased, so has the need for trained medical imaging workers. The most common route for entering these careers is through a two-year degree program, although certificates and bachelor's programs are also available.