RAD-206 • Chapter 9 Quiz

The range of brightness levels is a result of the tissues':

a. differential attenuation

b. differential contrast

c. differential detail

d. all of the above

b. differential contrast

When different tissues in the area being imaged have different absorption characteristics:

a. there will not be any differing brightness levels or contrast

b. there will be differing brightness levels or contrast

c. there will not be any radiographic density

d. b. & c.

b. there will be differing brightness levels or contrast

The smallest object that can be detected in a digital image is:

a. matrix resolution

b. object-to-image receptor distance (OID)

c. contrast resolution

d. spatial resolution

d. spatial resolution

Resolution is typically measured in:

line pairs per millimeter (lp/mm.)

To measure resolution, a __________ is necessary.

a. sensitometer

b. densitometer

c. resolution test pattern

d. resolution camera

c. resolution test pattern

Size distortion is also called:

a. elongation

b. magnification

c. shape distortion

d. foreshortening

b. magnification

When the image of a structure appears shorter than the actual structure, there is:

a. size distortion

b. elongation

c. magnification

d. shape distortion

d. shape distortion (foreshortening)

An artifact:

a. includes over- & underexposure of the image

b. is always due to items imaged that are not part of the anatomy (such as necklaces that were not removed)

c. is an unwanted image seen in a radiograph

d. none of the above

c. is an unwanted image seen in a radiograph

Failure to remove jewelry from the area being imaged results in:

a. a film screen image artifact

b. a digital image artifact

c. a film screen image & digital image artifact

c. a film screen image & digital image artifact

The image of a gold necklace in the area of interest appears light or bright. This is a __________ artifact.

a. plus-density

b. minus-density

c. it depends on the anatomy being imaged

d. none of the above

b. minus-density

The number of bits that determine the gray level that can be assigned to a pixel is the:

a. matrix

b. FOV

c. pixel

d. bit depth

d. bit depth

How many pixels does a 600 ' 600 matrix have?

a. 600

b. 1,200

c. 3,600

d. 360,000

d. 360,000

pixels = (# of rows)(# of columns)

pixels = (600)(600)

pixels = 360,000

The control that adjusts the contrast by adjusting the visible range of densities on the image is the:

a. window level

b. window width

c. window pane

d. all of the above

b. window width

Increasing the overall brightness of the digital image is accomplished by:

a. raising the window level

b. lowering the window level

c. increasing the window width

d. decreasing the window width

a. raising the window level

The ability to distinguish between structures that attenuate the x-ray beam similarly is:

a. brightness

b. contrast resolution

c. spatial resolution

d. noise

b. contrast resolution

Making the digital image appear with low contrast, with many shades of gray, is done by:

a. raising the window level

b. lowering the window level

c. increasing the window width (wide window width)

d. decreasing the window width (narrow window width)

c. increasing the window width (wide window width)

A film with too much density:

a. was exposed to too much light or radiation

b. has too much black metallic silver

c. will not make the anatomy visible

d. all of the above

d. all of the above

The diagnostic range of optical densities for general radiography typically falls between:

0.5 & 2 OD

With film screen imaging, the optical densities:

a. can be altered only after processing using the computer

b. cannot be altered after processing

c. can be altered only once after processing; after that, they are permanent

d. can only be increased after processing

b. cannot be altered after processing

The study of the relationship between the intensity of radiation exposure to the film & the amount of blackness produced after processing (density) is:

a. filmometry

b. densitometry

c. sensitometry

d. exposurometry

c. sensitometry

The device constructed of uniform absorbers of increasing thickness is a:

a. sensitometer

b. densitometer

c. penetrometer

d. aluminometer

c. penetrometer

A radiograph of a penetrometer looks like:

a. a single shade of gray

b. a variety of gray levels going from dark to light

c. step-wedge densities

d. b. & c.

d. b. & c.

The intensity of exposure is measured in:

a. mAs

b. mR

c. log relative exposure

d. kVp

c. log relative exposure

The area of the sensitometric curve where changes in exposure no longer affect the optical density is the:

a. base plus fog (B + F)

b. shoulder region

c. toe region

d. straight-line region

b. shoulder region

The area of the sensitometric curve representing the lowest densities is the:

a. base plus fog (B + F)

b. shoulder region

c. toe region

d. straight-line region

c. toe region

The location on the curve that corresponds to the optical density of 1 plus B + F is the:

a. exposure latitude

b. speed

c. film contrast

d. speed point

d. speed point

The lower the film's average gradient:

a. the faster the film speed

b. the slower the film speed

c. the higher the film contrast

d. the lower the film contrast

d. the lower the film contrast

Additional exposure after the curve reaches Dmax (as in duplicating film) results in:

a. higher contrast

b. lower contrast

c. increased density

d. decreased density

d. decreased density

The average gradient is used to determine the film's:

a. speed

b. exposure

c. contrast

d. optical density

c. contrast

With film screen, if an image is overexposed it will appear dark. The same situation with digital imaging will result in an image with:

a. too much brightness

b. appropriate brightness after adjusted by the computer

c. too little brightness which cannot be adjusted

d. an unacceptable level of brightness

b. appropriate brightness after adjusted by the computer

A digital image is composed of a combination of rows & columns recorded as a:

a. dynamic image

b. latent image

c. pixel

d. matrix

d. matrix

Each __________ is recorded as a single numerical value representing a single brightness level displayed on a monitor.

a. pixel

b. crystal

c. matrix

d. none of the above

a. pixel

A pixel's __________ determines the amount of the shades of gray that can be displayed in a digital image.

a. size

b. location

c. height

d. bit depth

d. bit depth

Fluoroscopy produces dynamic imaging by using __________ equipment.

a. image-intensified

b. flat panel detector

c. film-screen

d. image-intensified or flat panel detector

d. image-intensified or flat panel detector

Visibility of the anatomic structures is accomplished by balancing:

I. contrast

II. distortion

III. brightness

a. I & II only

b. I & III only

c. II & III only

d. I, II, & III

b. I & III only

What may happen when the digital image receptor is extremely overexposed?

a. excessive density

b. increased distortion

c. excessive contrast

d. saturation

d. saturation

The midpoint of the range of brightness levels visible on the digital image is determined by:

a. window level

b. window width

c. window pane

d. all of the above

a. window level

Which of the following is correct regarding the display feature windowing?

a. changing the window level will change the brightness level

b. increasing the window width will increase contrast

c. decreasing the window width will decrease contrast

d. changing the window level has no effect on the brightness level

a. changing the window level will change the brightness level

The ability of the imaging system to distinguish between small objects that attenuate the x-ray beam similarly is known as:

a. grayscale

b. spatial frequency

c. contrast resolution

d. brightness

c. contrast resolution

If there were no contrast, the radiographic image would include:

a. only the same shade of gray

b. black & white

c. light gray & dark gray

d. black & light gray

a. only the same shade of gray

Radiographic contrast:

a. produces sharper structural lines in the image

b. improves the magnification of the image

c. allows visibility of anatomic structures

d. produces sharper structural lines in the image & allows visibility of anatomic structures

c. allows visibility of anatomic structures

Which of the following contribute to subject contrast?

a. differences in tissue thickness

b. differences in tissue density

c. effective atomic number

d. all of the above

d. all of the above

__________ is a term used to evaluate accuracy of the anatomic structural lines recorded.

a. Contrast resolution

b. Spatial frequency

c. Spatial resolution

d. Detective quantum efficiency (DQE)

c. Spatial resolution

Spatial resolution can be increased by:

I. increasing the pixel pitch

II. increasing the pixel density

III. decreasing the pixel pitch

a. I & II only

b. I & III only

c. II & III only

d. I, II, & III

c. II & III only

Increasing the matrix size for a fixed field of view (FOV) results in:

a. smaller pixel sizes

b. larger pixel sizes

c. increased spatial resolution

d. smaller pixel sizes & increased spatial resolution

d. smaller pixel sizes & increased spatial resolution

An imaging system that can resolve a greater number of line pairs within 1 mm. is said to have:

a. improved spatial resolution

b. decreased spatial resolution

c. improved brightness

d. decreased brightness

a. improved spatial resolution

Which of the following is correct regarding spatial frequency?

I. small objects have lower spatial frequency

II. small objects have higher spatial frequency

III. large objects have lower spatial frequency

a. I & II only

b. I & III only

c. II & III only

d. I, II, & III

c. II & III only

The radiographic misrepresentation of either the size (magnification) or the shape of the anatomic part is called:

a. brightness

b. contrast

c. sharpness

d. distortion

d. distortion

Objects that are being imaged can be misrepresented radiographically by distortion of their shape, this is called:

a. size distortion

b. shape distortion

c. sharpness distortion

d. size & sharpness distortion

b. shape distortion

When the image of a structure appears longer than the actual structure, there is:

a. size distortion

b. foreshortening

c. magnification

d. elongation

d. elongation

An artifact that is imaged within the patient's body is a:

a. anatomic anomaly

b. foreign body

c. double exposure

d. none of the above

b. foreign body