Deck 5: Radiographic Image Quality: Geometric Properties

Question 1

When the SID is divided by the SOD, what is the result called?

A) Magnification factor
B) Degree of unsharpness
C) OID
D) Image width

Answer 1

Magnification factor

Question 2

The unit of line pairs per millimeter is a measure of:

A) distortion.
B) resolution.
C) magnification.
D) quantum mottle.

Answer 2

resolution.

Question 3

What effect will using a slower speed imaging system have on recorded detail?

A) Increased recorded detail
B) Decreased recorded detail
C) No effect on recorded detail

Answer 3

Increased recorded detail

Question 4

Using a small focal spot size may be prohibited due to the:

A) amount of heat produced by x-ray exposure.
B) amount of exposure time used.
C) SID used.
D) speed of the film-screen system.

Question 5

The misrepresentation of the size of an object is:

A) shape distortion.
B) magnification.
C) foreshortening.
D) elongation.

Question 6

Providing clear instructions to the patient is a primary method for reducing unsharpness due to:

A) shape distortion.
B) motion.
C) geometric properties.
D) size distortion.

Question 7

Poor film-screen contact will result in:

A) increased patient exposure.
B) decreased patient exposure.
C) increased recorded detail.
D) decreased recorded detail.

Question 8

During the selection of the focal spot size, the radiographer is really determining the:

A) angle of the anode used.
B) actual size of the filament used.
C) number of electrons available for tube current.
D) distance the electrons travel from cathode to anode.

Question 9

Shape distortion can be created by:

A) off-centering the central ray.
B) angling the central ray.
C) increasing the SID.
D) a and b only

Question 10

Magnification is affected by:

A) AEC.
B) OID.
C) SID.
D) b and c

Question 11

If the image size measures 4.6 inches and the magnification factor is 1.42, what is the size of the object?

A) 2.43 inches
B) 3.24 inches
C) 5.63 inches
D) 6.53 inches

Question 12

The most detrimental factor to maximum recorded detail is:

A) increased OID.
B) decreased SID.
C) large focal spot size.
D) motion.

Question 13

The relationship of the focal spot size, SID, and OID specifically impacts the _____ of the image.

A) visibility of recorded detail
B) image receptor unsharpness
C) geometric unsharpness
D) distortion

Question 14

If the object size measures 6.2 inches and the image size measures 7.5 inches, what is the magnification factor?

A) 0.83
B) 1.21
C) 1.30
D) 13.7

Question 15

The SOD can be found by:

A) adding SID and OID.
B) adding the MF to the OID.
C) subtracting the OID from SID.
D) subtracting the SID from the MF.

Question 16

What effect will using a higher grid ratio have on recorded detail?

A) Increased recorded detail
B) Decreased recorded detail
C) No effect on recorded detail

Question 17

In order to image a structure that is located anteriorly in the body, it is best radiographed to minimize magnification by doing a _____ projection.

A) posterior-anterior
B) anterior-posterior
C) lateral
D) oblique

Question 18

What effect will increasing SID have on recorded detail?

A) Increased recorded detail
B) Decreased recorded detail
C) No effect on recorded detail

Question 19

The property of the x-ray beam that impacts the unsharpness on the radiograph is beam:

A) quality.
B) quantity.
C) divergence.
D) restriction.

Question 20

What is the geometric unsharpness when the focal spot measures 0.8 mm, the SID is 40 inches (100 cm), and the OID is 2 inches (5 cm)?

A) 0.042 mm
B) 0.42 mm
C) 4.2 inches
D) 4.2 cm

Question 21

The pinhole camera is a device that is used to measure:

A) SID.
B) OID.
C) focal spot size.
D) resolution.

Question 22

The smallest detail that can be detected in an image refers to:

A) contrast resolution.
B) spatial resolution.
C) geometric unsharpness.
D) distortion.

Question 23

All of the geometric factors and those that determine the amount of image distortion are equally important for digital and film-screen imaging.

Question 24

SID indicators should be accurate within ______ of the SID.

A) 1%
B) 2%
C) 5%
D) 10%

Question 25

The ability of the system to differentiate between two small objects that have similar subject contrast refers to:

A) contrast resolution.
B) spatial resolution.
C) geometric unsharpness.
D) distortion.