![]() Structure are more likely to be caused by _within a projection, which is known as _ _. between projections undersampling leads to an effect known as view aliasing Stripes appearing close to the Used to reconstruct a CT image is one of the determiningįactors in image quality. Image is reconstructed Undersampling The number of projections Adaptive Filtration -Some manufacturers use Photon Starvation: Automatic Tube Current Modulation On some scanner models, traveling horizontally, horizontal streaks Photon Starvation - Solution Increase the tube current. The reconstruction has the effect of magnifying the noise resulting in _ _ in the image. Phonton starvation: When x-ray beam is _ _, theĪttenuation is greatest and insufficient photons reach the detector & very noisy projections are produced at these tube angulations. Can occur in highly attenuating areas - shoulders. how can partial volume artifact be avoided use thin acquisition section width photon starvation -Potential source of serious streaking artifacts. Partial volume artifact -Arise when voxel containĪrtifact. bowtie filter Beam hardening correction software -An iterative correctionĬross section. Beam hardening correction software filtration -A flat piece of attenuating Streaks and Dark Bands can occur in -bony regions of the body Hardened less than when it passes through both Through one of the objects at certain tube portions is Occurs because portion of the beam that passes ![]() Streaks and Dark Bands -In very heterogeneous cross sections, dark bands or streaks appear between two dense objects in an The resultant attenuation profile differs from the ideal ![]() Cupping artifact -X-rays passing through the Appearance of dark bands / streaks between dense Two types of artifacts can result from beam hardening 1. Beam hardening -The mean energyĪnd it becomes harder. Beam hardening artifact: As the beam passes through the object, it becomes "harder". Helical & multisection artifacts: Produced by the ![]()
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