Spatial Resolution Worksheet and Abbreviations

Spatial resolution/detail sharpness can be improved by decreasing:

1. The SID

2. The OID

3. Patient/part motion

A. 1 only

B. 3 only

C. 2 and 3 only

D. 1, 2, and 3

E. 1 and 3

C. 2 and 3 only

Types of shape distortion include:

1. Magnification

2. Elongation

3. Foreshortening

A. 1 only

B. 1 and 2 only

C. 2 and 3 only

D. 1, 2, and 3

C. 2 and 3 only

In which of the following ways does SID affect sharpness of image details?

A. Image detail sharpness is directly related to SID

B. Image detail sharpness is inversely related to SID

C. As SID increases, image detail sharpness decreases

D. SID is not an image detail sharpness factor

A. Image detail sharpness is directly related to SID

Misalignment of the tube-part-IR relationship results in:

A. Shape distortion

B. Size distortion

C. Magnification

D. Blur

A. Shape distortion

Foreshortening of the radiographic image is a result of:

A. Tube angulation

B. Increased OID

C. Decreased SID

D. Improper part alignment

D. Improper part alignment

OID is related to image sharpness/spatial resolution in which of the following ways?

A. Sharpness/resolution is directly related to OID

B. Sharpness/resolution is inversely related to OID

C. As OID increases, so does sharpness/resolution

D. OID is unrelated to sharpness/resolution

B. Sharpness/resolution is inversely related to OID

Which of the following factors result in poor spatial resolution? (Select 4)

A. Long SID

B. Long OID

C. Large focal spot

D. Small focal spot

E. Patient motion

F. Magnification

B, C, E, F — Long OID, Large focal spot, Patient motion, Magnification

Lower spatial resolution may be caused by which of the following factors?

A. Short OID

B. Long SID

C. Small focal spot

D. Wide pixel pitch

D. Wide pixel pitch

Spatial resolution is:

A. Photographic representation of the part being radiographed

B. Controlled by kVp

C. Controlled by mAs

D. Geometric representation of the part being radiographed

D. Geometric representation of the part being radiographed

Which of the following will result in higher spatial resolution? (Select 3)

A. Long SID

B. Long OID

C. Short SID

D. Short OID

E. Large focal spot

F. Small focal spot

A, D, F — Long SID, Short OID, Small focal spot

Optimal spatial resolution may be created using which of the following factors?

A. Large focal spot

B. Narrow pixel pitch

C. Long OID

D. Short SID

B. Narrow pixel pitch

Distortion may be described as:

A. Misrepresentation of an anatomic structure on the image

B. Foreshortening

C. Elongation

D. Magnification

A. Misrepresentation of an anatomic structure on the image

Elongation and foreshortening are examples of:

A. Size distortion

B. Shape distortion

C. Motion

D. Distortion caused by short SID and long OID

B. Shape distortion

Magnification is caused by: (Select 2)

A. Short SID

B. Long SID

C. Short OID

D. Long OID

A, D — Short SID and Long OID

Distortion can be caused by:

1. Tube angle

2. The position of the organ or structure within the body

3. The radiographic positioning of the part

A. 1 only

B. 1 and 2 only

C. 2 and 3 only

D. 1, 2, and 3

D. 1, 2, and 3 (ALL)

All of the following are related to spatial resolution, EXCEPT:

A. Milliamperage

B. Focal spot size

C. SID

D. OID

A. Milliamperage

OID is related to image sharpness/spatial resolution in which of the following ways?

A. Sharpness/resolution is directly related to OID

B. Sharpness/resolution is inversely related to OID

C. As OID increases, so does sharpness/resolution

D. OID is unrelated to sharpness/resolution

B. Sharpness/resolution is inversely related to OID

A technologist is asked to develop a new protocol for knee x-ray that will decrease magnification. Which of the following technical factors should be increased?

A. Focal spot size

B. SID

C. Grid ratio

D. OID

B. SID

Increasing the effective focal spot will most likely increase:

A. Patient dose

B. Beam penetrability

C. Unsharpness (Penumbra)

D. Contrast

C. Unsharpness (Penumbra)

While working with a patient who has a broken humerus, the technologist was unable to bring the patient's arm into alignment with the plane of the image receptor. What is the most likely result?

A. Magnification

B. Foreshortening

C. Underexposure

D. Poor contrast resolution

B. Foreshortening

What's another word for unsharpness?

Penumbra

DQE (detective quantum efficiency)

How efficiently the detector uses radiation.

Measures how efficiently an image receptor uses the x-ray photons it receives to create a quality image. A higher DQE = better image quality with less radiation exposure.

DQA (Digital Quality Assurance)

Making sure the digital system works correctly.

A quality-control program for digital imaging systems that makes sure the equipment is working properly and consistently producing good-quality images.

MTF (modulation transfer function)

Detail/sharpness.

Measures how well an imaging system can reproduce small details and differences in contrast. It is a measure of spatial resolution/detail. A higher MTF = better detail reproduction.

SNR (Signal-to-Noise Ratio)

Overall signal vs. noise.

Compares the amount of useful image information (signal) to the amount of unwanted information (noise). A higher SNR = less noticeable noise and better image quality.

CNR (contrast to noise ratio)

Contrast/differences between structures vs. noise.

Measures how well you can distinguish one structure from another compared with the amount of noise present. A higher CNR = structures are easier to tell apart.