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15 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Distortion |
One of the geometric properties affecting radiographic image quality. Misrepresentation of the size and shape of the structures being examined |
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Positioning |
Distortion is directly related to ____. Only careful attention to the distances, Direction, and relations between the anatomical part, Central Ray, and image receptor can minimize distortion |
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Magnification |
Only _____ is possible and all size Distortion is controlled by the radiographic distances like SID and OID. In digital image receptor systems, post-processing can resize the image |
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Magnification size distortion |
Is controlled by positioning the body part and Tube to maximize SID while minimizing OID |
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Source to entrance skin distance (SOD) |
The oid is important because it establishes the |
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Source to entrance skin distance |
Large OID with short SOD = High entrance skin exposure.
Short OID with large SOD = low skin entrance exposure |
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The magnification Factor formula |
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Elongation |
Occurs when the tube or the image receptor is improperly aligned |
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Foreshortening |
Occurs only when the part is improperly aligned |
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SID |
Is a major factor for magnification. As it increases it decreases magnification. Advocated by experts for increases in this. Advocated by experts for increases in this. Decreased entrance skin exposure (ESE) Decreased entrance skin exposure (ESE) |
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OID |
Is a critical distance for magnification and spatial resolution. Should be minimized whenever possible, to minimize magnification and improve resolution |
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Factors affecting shape distortion |
The alignment including, Central Ray, atomical part, and image receptor & Angulation including degree and direction The preferred relationship of these is perpendicular between focal spot and receptor |
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Shape distortion |
Includes foreshortening and elongation.Misrepresentation by unequal magnification across dimension of object Misrepresentation by unequal magnification across dimension of object Misrepresentation by unequal magnification across dimension of object |
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Better spatial resolution |
Better detail is achieved by angling body part rather than angling Central ray for a purposeful distortion |
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Evaluating shape distortion |
Cannot be calculated and has subjective evaluation. |
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