There are four main types of X-ray imaging systems, all of which have different general purposes. Today, digital radiography (DR) is the standard X-ray system, overtaking film X-rays due to the benefits of computer software. Alongside software, the images can be artificially clarified to create an overall stronger image. Another form of X-ray system is computed tomography or CT scan. CT scans can capture bone, soft tissue, and blood vessels in one, while a standard X-ray cannot. In addition, they are generally more pinpointed in a specific area of the body but generally require exposure to more radiation compared to a standard X-ray. A fluoroscopy is a real-time X-ray imaging system that is commonly used to aid specific procedures, mainly in orthopedics and gastrointestinal investigations. The final main type of X-ray imaging includes mammography, which is specifically used to help diagnose and screen for breast cancer or other breast diseases. Additionally, a screening using mammography can be easily scheduled for women because of how common breast cancer is. Scheduling any other X-ray imaging for screening is typically not allowed. In general, a doctor must approve and see a fit reason for one.