# CT- Basic Principles of CT

 what does CT accomplish that conventional radiographs cant? scans thin sections of the body with a narrow x-ray beam that roatates around the body, producing images of each cross sectionallows for the differentiation between tissues of similar densities what are the main advantages of ct over regular xray? main advantages of ct over regular xray are in the elimination of superimposed structures, the ability to differentiate small differences in density of anatomic structures and abnormalities and the superior quality of the images. what does the z-axis, x-axis, and y-axis refer to in CT imaging? z-axis: the thickness of the cross-sectional slicex-axis: widthy-axis: height what does an x-axis and y-axis form? 2 dimensional squares or a pixel (picture element) what does an x-axis, y-axis and z-axis form? a cube or voxel (volume element) what is a matrix? the grid formed from the rows and columns of pixels. what is the most common matrix size? 512x512 the total number of pixels in a matrix is calculated how? multiply number of rows and the number of columns: i.e 512x512= 262,144 what happens to pixel size when matrix size increases? pixel size decreases because the outside perimeter of the square is held constant. what is attentuation? the degree to which an xray beam is reduced by an object what does Hounsfield units quantify? the degree that a structure attenuates an x-ray beam what are the hounsfield units for water, air, and bone?  distilled water = 0air = -1000bone = 1000 Authorswtjo3joe ID233221 Card SetCT- Basic Principles of CT Descriptionbasic principles of ct Updated2013-09-06T23:06:39Z Show Answers