Early detection of health problems is very important in diagnosing or sometimes eliminating disease at its onset. Over the last decades, various imaging techniques such as X-rays, ultrasounds, MRI (Magnetic Resonance Imaging) and CT or CAT scans (Computerized Assisted Tomography) have been developed and applied for diagnostic as well as therapeutic medical care. However, in recent years many doctors, and especially radiologists, became concerned with overuse of certain diagnostic techniques -, in particular those that expose patients to radiation.