MISREGISTRATION: discription due to respiratory motion , appearance can reduced by allowing volumetric data acqusition of up to 60 cm in less than a minuite motion is minimized appearance of skipping and overlapping.

SCALLOPING: discription : bulging change in skull structure  appearance skull tomagraphy particularly in slice position in which the skull diameter quickly changes its axial direction to correct change pitch factor  a linear filter is added that removes scalloping artifacts.

BANDING: dark bands can appear between two dense objects in an image.They occur because the portion of the beam that passes through one of the objects at a certain tube position( low energy photons) is hardened less than when it passes through both obeject at other tube position.

 

STAIR STEPPING; appearance: around the edge of structures . they are produced when wide collimation and non overlapping reconstruction intervals are used.

stair stepping artifacts are elimated by reformatting images from this section data obta ined with todays scanners.

PITCH EFFECTS : discription :  table feed per rotation. 

Effects larger table feed the faster body region can be scanned which result in poor image quality. good image can be obtained by redu cing the pitch and keeping it at a pitch factor .

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