HOW CT SCANS WORK: CT scans use X-rays to image the body. X-rays can pass through most materials. It all depends on the size of the atoms that make up the material; larger atoms absorb X-ray photons, while smaller atoms do not, allowing X-rays to pass right through. For instance, the soft tissue in the body is composed of smaller atoms, so it doesn't absorb X-rays very well. But calcium atoms in the bones are much larger and do absorb X-rays. A camera on the other side of the patient records the patterns of X-ray light passing through the patient's body. In a CT scan, a series of X-ray beams is directed through the body from different angles. This creates cross-sections so scientists can get a better view of the body. The images are put together by a computer into a stack of pictures that can be viewed rapidly, like flipping through a deck of cards.
ABOUT COMPUTER MODELING: Computer modeling is used to simulate the structure and appearance both of static objects, such as building architecture, and of dynamic situations, such as a football game. Computer models can enable the user to test the consequences of choices and decisions. They can provide cutaway views that let you see aspects of an object that would be invisible in the real artifact, as well as visualization tools that can provide many different perspectives. Physical models that reproduce behavior are limited by the physics of the world, while computer models have much looser bounds. Physical models of living things can reproduce very few behaviors, compared to simulation models, and physical models simply cannot capture the sorts of species-level and conceptual-level phenomena that artificial life and artificial intelligence models do. Computer models enable you to run companies and civilizations, fight battles, play football games and evolve new species.
The Institute of Electrical and Electronics Engineers, Inc.-USA, contributed to the information contained in the TV portion of this report.