CT Computed Tomography PDF
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ESRAA HASSAN
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This presentation provides an overview of computed tomography (CT), including its use of X-rays, tissue density measurement, and various types of CT scans.
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Computed Tomography CT ESRA A HASS AN INTRODUCTION CT (computed tomography) uses X-rays to obtain images. A heated cathode releases high-energy electrons, which in turn release their energy as X-ray radiation. X-rays pass through tissues and hit a detector on the other side. The denser a tissue...
Computed Tomography CT ESRA A HASS AN INTRODUCTION CT (computed tomography) uses X-rays to obtain images. A heated cathode releases high-energy electrons, which in turn release their energy as X-ray radiation. X-rays pass through tissues and hit a detector on the other side. The denser a tissue, the more X-rays it absorbs. Compared to plain film, CT is able to distinguish more subtle density differences and there is no overlap of structures. Current CT machines use ‘Spiral CT’. This consists of a single radiation source with multiple detectors which rotates around the patient, obtaining a block of data as the patient is moved through. Tissue density is measured in Hounsfield unit (HU) This define as Air=-1000 HU ; Water =0 HU ;Bone =+1000 HU air
