Over the past several decades, the use of ionizing radiation in medical imaging has increased dramatically. This has resulted in a substantial increase in the radiation dose humans are exposed to. In 1950, approximately 25 million radiographic and fluoroscopic exams were performed. This number skyrocketed to nearly 300 million by the mid-2000s. In the 1980s, only 15 percent of all artificial radiation exposure was on account of medical imaging; by the mid-2000s, this figure had risen to almost 50 percent.