Distortion
Object thickness
The OID of a thick object changes measurably across the object
Significant
As the object's position is shifted laterally from the central ray, spatial distortion can become ___
Minimal
Distortion is ___ for objects lying along the central ray
Correct patient positioning
Distortion is possible in every radiograph if ___ is not maintained
More distorted
Due to the change of the OID the image of that structure is ___ than an image of a thinner structure
Directly related to positioning
Factors that control distortion are ___
Object thickness, object position and spatial distortion
Geometric Principles Three conditions contribute to image distortion
Diffuse blurring
If sufficient magnification is achieved by a reasonable OID and a short SID, the object may be visualized as a diffuse gray area.
Shape distortion
___ is the misrepresentation by unequal magnification of the actual shape of the structure being examined
Maximize SID while minimizing OID
Magnification size distortion is controlled by positioning the body part and x-ray tube to ___
Definition of distortion
Misrepresentation of the size and shape of the structure being examined
Foreshortening
Projects the object so it appears shorter than it really is. Occurs only when the part being examined is improperly aligned
Elongation
Projects the object so it appears to be longer than it is. Occurs when the tube or IR are improperly aligned
Distortion (Size)
Reduced magnification size distortion increases the resolution of recorded detail
Source to image distance and Object to image distance
Size distortion (magnification) is a function of:
Spatial distortion
The misrepresentation in the image of the actual spatial relationship among objects
Object position
When the object plane and the image plane are parallel, the image is not distorted