Distortion is a misrepresentation of
size only.
shape only.
size and shape.
detail.
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Terms in this set (31)
Which of the following occurs when the tube or the image receptor are not properly aligned? elongation magnification foreshortening minificationelongationWhich one of the following occurs when the part is improperly aligned? elongation magnification foreshortening minificationforeshorteningProper alignment is achieved when the central ray is ____ to the part and ____ to the image receptor. perpendicular; parallel parallel; perpendicular perpendicular; perpendicular parallel; parallelperp; perpWhen the position of the patient is reversed, the direction of the tube angle must be ____ to maintain the relationship. maintained decreased increased reversedreversedBecause the x-ray beam is divergent, -minification is impossible. -minification is collimated off from the edges of the beam. -minification is greater with a smaller target angle. -minification is greater with a larger target angle.minification is impossible.X-ray tube angulations inherently increase spatial resolution. change the SID. introduce magnification to some degree. both b and cboth b and c.In order to achieve a true SID of 40" with an x-ray tube angle of 30 degrees, the overhead scale should read 23 inches. 95 cm. 34.6 inches. both b and c.34.6 inches.Performing a routine chest radiograph in the anterioposterior (AP) projection will -decrease heart size on the image. -demonstrate higher resolution of the anterior ribs. -produce improved resolution of the thoracic spine. -decrease breast exposure.produce improved resolution of the thoracic spine.A renal calculus that measures 0.2 mm in size -cannot be visualized with an effective focal spot of 0.5 mm focal spot due to penumbral overlap. -is best seen with magnification and a large focal spot. -most likely will be visualized with a small radiographic tube angle using a large target angle. -all of the above.cannot be visualized with an effective focal spot of 0.5 mm focal spot due to penumbral overlap.Opening up the intervertebral joints of the cervical spine would best be accomplished with -the patient in a PA projection at 72" SID. -the patient in an AP projection with a 40" SID. -a perpendicular central ray at 72" SID. -the patient in a PA projection with a 40" SID.the patient in an AP projection with a 40" SID.With digital image receptors (CR/DR) -the geometric factors of distortion do not apply. -EI#s are inaccurate due to elongation distortion. -computer postprocessing corrects for shape distortion. -none of the above.none of the above.A radiographic magnification factor(MF) of −.15 indicates -the object size and image size are nearly equal. -nothing, since negative MF is not possible. -the image size is smaller than the object size. -a change in OID is needed.nothing, since negative MF is not possible.Enlargement of a digital radiographic image on the review monitor, is an example of purposeful geometric magnification. electronic magnification. shape distortion. digital histogram distortion.electronic magnification.Positioning patients is intended to eliminate anatomical superimposition, from a radiologist perspective. To optimize image resolution it is best to -keep the central ray and receptor perpendicular to the patient's anatomy, and rotate the part. -minimize central angulation and rotate the part only slightly. -use the small focal spot and extend the degree of part rotation. -lower the SID and increase the OID with part rotation.keep the central ray and receptor perpendicular to the patient's anatomy, and rotate the part.Shape distortion is calculated -as the ratio of SID and SOD. -using the tube angle and OID. -automatically in the computer postprocessing. -none of the above.none of the above.ratio between image size and MFobject sizean image in which the object is actually shorterelongationbest seen with the patient supinekidneysMFSID SODSID ÷ MFsodinherently magnified in AP projectionpatella