Deck 15: Computed Radiography

Question 1

Spatial resolution,contrast resolution,noise,and artifacts are identical in screen-film imaging and computed radiography.

Answer 1

False

Question 2

Computed radiography cassettes and film/screen cassettes can be used interchangeably with any x-ray imaging system.

Answer 2

True

Question 3

Computed radiography screens respond to radiation with _____.

A) fluorescence
B) electron emission
C) photostimulable luminescence
D) biological phosphorescence

Answer 3

photostimulable luminescence

Question 4

A photostimulable phosphor in a metastable state will emit light _____.
I. immediately
II. when stimulated by light
III. over time

A) I
B) II
C) II & III
D) I, II & III

Question 5

The four steps of creating an image with computed radiography are _____.

A) metastable state, stimulate, read, and erase
B) erase, stimulate, metastable state, and read
C) read, erase, stimulate, and metastable state
D) metastable state, read, erase, and stimulate

Question 6

The 400 speed film-screen systems are still faster than computed radiography image receptors.

Question 7

The computed radiography cassette is called a(n)_____ plate.

A) optical
B) imaging
C) laser
D) thermoluminescent

Question 8

Following the laser stimulation of the photostimulable phosphor,the excited electrons are _____.

A) completely stabilized
B) mostly stabilized
C) still excited
D) completely removed

Question 9

With computed radiography the contrast is _____.

A) controlled by kVp
B) controlled by mAs
C) constant regardless of radiation exposure
D) impossible to change

Question 10

Digital radiography was first introduced by _____.

A) GE in 1998
B) Fuji in 1981
C) Kodak in 1975
D) DuPont in 1965

Question 11

The photostimulable phosphor screen is handled in a _____.

A) reader
B) darkroom
C) film processor
D) film changer

Question 12

Europium is the _____ of the photostimulable phosphor.

A) image buffer
B) scintillator
C) phosphor
D) activator

Question 13

The computed radiography image has _____.

A) narrow exposure latitude
B) wide exposure latitude
C) improved contrast resolution
D) both B and C

Question 14

The computed radiography reader is made up of _____,_____,and _____ modules.
I. mechanical
II. chemical
III. optical
IV. computer

A) I, II, III
B) II, III, IV
C) I, III, IV
D) I, II, IV

Question 15

The digital imaging plate can sit for some time after the erase cycle.

Question 16

The principal source of noise in computed radiography is _____.

A) scatter radiation
B) background radiation
C) computer noise
D) phosphor scatter

Question 17

The laser is one of the _____ features of the computed radiography reader.

A) computer
B) chemical
C) mechanical
D) optical

Question 18

Optical filters are used to filter out the _____ light and allow the _____ light to reach the photodetector.

A) stimulating, emitted
B) emitted, stimulated
C) emitted, monochromatic
D) stimulating, monochromatic

Question 19

The output signal from the photostimulable phosphor plate is converted from analog to digital by the _____.

A) optical system
B) computer controls
C) photodetector
D) drive mechanism

Question 20

Computed radiography and screen-film imaging both have a(n)_____.

A) image receptor response function
B) characteristic curve
C) digital image
D) latent image

Question 21

Switching from screen-film imaging to computed radiography can _____ patient dose.

A) increase
B) reduce
C) not effect
D) remove

Question 22

_____ is prevented by flooding the erased imaging plate with bright light.

A) Image fog
B) Noise
C) Overexposure
D) Ghosting

Question 23

Computed radiography imaging produces _____ gray levels.

A) 30
B) 100
C) 10,000
D) 1,000,000

Question 24

When switching from screen-film imaging to computed radiography,which step is eliminated?

A) creating the latent image
B) reloading the cassette
C) selecting an exposure technique
D) processing the latent image

Question 25

The laser beam must be less than 100 nm in diameter in order to maintain _____.

A) consistent beam shape
B) smooth image edges
C) high spatial resolution
D) high speed