COMPUTERIZED AXIAL TOMOGRAPHY

. It is a technique using x-rays or ultrasound waves to produce an image of interior parts of the body.
Its is also a medical imaging method employing tomography where digital processing is used to generate a three-dimensional image of the internals of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation.
CT imaging is particularly useful because it can show several types of tissue –lung, bone, soft tissue and blood vessels—with great clarity. Using specialized equipment and expertise to create and interpret CT scans of the body, radiologists can more easily diagnose problems such as cancers, cardiovascular disease, infectious disease, trauma and muskuloskeletal disorders. Imaging anatomical information from a cross-sectional plane of the body, each image generated by a computer synthesis of x-ray transmission data obtained in many different directions in a given plane. Developed by British electronics engineer Godfrey Hounsfield, CT has revolutionized diagnostic medicine. Hounsfield linked x-ray sensors to a computer and worked out a mathematical technique called algebraic reconstruction for assembling images from transmission data. Subsequently, the speed and accuracy of machines has improved many times over. CT scans reveal both bone and soft tissues, including organs, muscles, and tumors. Image tones can be adjusted to highlight tissues of similar density, and, through graphics software, the data from multiple cross-sections can be assembled into 3-D images. CT aids diagnosis and surgery or other treatment, including radiation therapy in which effective dosage is highly dependent on the precise density, size, and location of a tumor. Because it provides detailed, cross- sectional views of all types of tissue
About the machine:
The CT scanner is a large, square machine with a hole in the center. The patient lies still on a table that can move up or down and slide into and out from the center of the hole. Within the machine an X-ray tube on a rotating gantry moves around the patient's body to produce the images, making clicking and whirring noises as the table moves. In many ways CT scanning works very much like other X-ray examinations. Very small, controlled amounts of x-ray radiations are passed through the body and different tissues absorb radiation at different rates. With plain radiology, an image of the inside of the body is captured when special film is exposed to the absorbed x-rays. With CT the film is replaced by an array of detectors that measure the x-ray profile.

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