Deck 10: Digital Image Receptors

Question 1

The part of a PSP plate that reduces and carries away static electricity is the

A) conductive layer
B) structured phosphor layer
C) turbid phosphor layer
D) support layer

Answer 1

conductive layer

Question 2

The part of a PSP plate that gives some rigidity to the plate is the

A) conductive layer
B) structured phosphor layer
C) turbid phosphor layer
D) support layer

Answer 2

support layer

Question 3

Which of the following statements is true concerning direct radiography (DR) systems?

A) Use storage phosphors to temporarily store energy representing the image signal.
B) Require that the storage phosphor undergoes a process to extract the latent image.
C) Have detectors that directly capture and read out an electronic image signal.
D) Use storage phosphors to temporarily store energy representing the image signal and require that the storage phosphor undergoes a process to extract the latent image.

Answer 3

Have detectors that directly capture and read out an electronic image signal.

Question 4

This part of the reader moves the PSP plate through the reader

A) Photodetector
B) Optical system
C) Drive mechanism
D) Photostimulable luminescence

Question 5

Which of the following digital detectors continues to improve and can be used in mammography and dental radiography?

A) photostimulable phosphor (PSP)
B) complementary metal oxide semiconductor (CMOS)
C) light-to-computer device (LTC)
D) charge-coupled device (CCD)

Question 6

At the time of processing, the energy of the trapped electrons is released by exposure to a laser in a process called

A) photodetector
B) scintillation
C) phosphorescence
D) photostimulable luminescence

Question 7

The part of the reader that consists of a laser, optical filters, light-collecting optics, and beam-shaping devices that is designed to project and guide a precisely controlled laser beam back and forth across the plate as the plate moves through the scan area is the

A) photodetector
B) optical system
C) drive mechanism
D) photostimulable luminescence

Question 8

The trapped electrons in the conduction band of the PSP form the

A) latent image
B) manifest image
C) visible image
D) latent image and visible image

Question 9

The part of the reader that senses the light released from the PSP plate is the

A) photodetector
B) optical system
C) drive mechanism
D) photostimulable luminescence

Question 10

Approximately what percentage of the removed electrons are "trapped" in the conduction band?

A) 1%.
B) 25%.
C) 50%.
D) 99%.

Question 11

The type of phosphor found in the PSP plate for computed radiography is

A) plastic
B) amorphous selenium
C) barium fluorohalide
D) cesium iodide

Question 12

Europium serves as

A) an activator for the phosphor
B) the protective layer
C) the reflective part of the PSP plate
D) the conductive layer

Question 13

The part of a PSP plate that includes columnar crystals, resembling needles on end, is the

A) conductive layer
B) structured phosphor layer
C) turbid phosphor layer
D) support layer

Question 14

Where is the PSP plate located?

A) On the inside the cassette.
B) On the outside the cassette.
C) Computer workstation.
D) On the detector array.

Question 15

Which of the following imaging systems uses a cassette, a photostimulable phosphor plate, a plate reader, and a computer workstation?

A) Computed radiography.
B) Computed tomography.
C) Direct radiography.
D) Computed radiography and computed tomography.

Question 16

When the PSP plate is exposed to the laser of the reader, the energy is released and converted to a digital signal, becoming a

A) latent image
B) analog image
C) primary image
D) manifest image

Question 17

This part of the plate reflects light released during the reading phase toward the photodetector

A) protective layer
B) reflective layer
C) phosphor layer
D) conductive layer

Question 18

The part of a PSP plate that includes a random distribution of crystals is the

A) conductive layer
B) structured phosphor layer
C) turbid phosphor layer
D) support layer

Question 19

Which of the following statements is true concerning computed radiography (CR) systems?

A) Use storage phosphors to temporarily store energy representing the image signal.
B) Require that the storage phosphor undergoes a process to extract the latent image.
C) Have detectors that directly capture and read out an electronic image signal.
D) Use storage phosphors to temporarily store energy representing the image signal and require that the storage phosphor undergoes a process to extract the latent image.

Question 20

Following the detection of the light released from the phosphor layer, the amplified signal is sent to the _____________ to convert it to a digital electronic signal for the display computer

A) digital-to-analog converter (DAC)
B) analog-to-digital converter (ADC)
C) light-to-computer device (LTC)
D) none of these

Question 21

Part of the direct-capture DR system, the __________ absorbs x-rays and produces an electric signal

A) CCD
B) photoconductor
C) TFT
D) scintillator

Question 22

A material that absorbs x-ray energy and emits visible light in response is a

A) charge-coupled device (CCD)
B) photoconductor
C) thin film transistor (TFT)
D) scintillator

Question 23

Put the following sequence of events in this indirect capture system in order
1) The CCD converts the energy to an electronic signal
2) The light energy is then transmitted to the CCD
3) X-rays are absorbed by the scintillator and converted to light
4) Electronic signal is sent to the computer work station for processing and display

A) The CCD converts the energy to an electronic signal, The light energy is then transmitted to the CCD, X-rays are absorbed by the scintillator and converted to light, Electronic signal is sent to the computer work station for processing and display
B) The light energy is then transmitted to the CCD, The CCD converts the energy to an electronic signal, X-rays are absorbed by the scintillator and converted to light, Electronic signal is sent to the computer work station for processing and display
C) X-rays are absorbed by the scintillator and converted to light, The CCD converts the energy to an electronic signal, The light energy is then transmitted to the CCD, Electronic signal is sent to the computer work station for processing and display
D) Electronic signal is sent to the computer work station for processing and display, X-rays are absorbed by the scintillator and converted to light, The CCD converts the energy to an electronic signal, The light energy is then transmitted to the CCD

Question 24

The values of interest (VOI)

A) is the graphic representation of a data set
B) determine what section of the histogram data set should be included in the displayed image
C) determine what section of the histogram data set should be included in the latent image
D) is the useful area of the digital image receptor

Question 25

Amorphous selenium is used as the

A) photoconductor for indirect capture DR imaging
B) photodetector for indirect capture DR imaging
C) photoconductor for direct capture DR imaging
D) photodetector for direct capture DR imaging

Question 26

Which of the following is true concerning direct capture DR imaging?

A) The DR direct-capture method does not use a scintillator
B) The DR direct-capture method uses a photoconductor and TFT array
C) The DR direct-capture method avoids the loss of resolution caused by indirect-capture methods
D) All of these are true

Question 27

Which of the following statements is false concerning Complimentary Metal Oxide Semiconductors (CMOSs)

A) Each detector element has its own amplifier, photodiode, storage capacitor, and are surrounded by transistors
B) They have light sensitivity and resolution that is equal to or better than CCDs
C) They are very inexpensive to manufacture
D) They are currently options for mammography and dental radiography machines

Question 28

Which of the following digital image receptors does not use a network of TFTs?

A) Indirect capture with CCD
B) Indirect capture with amorphous silicon photodetector
C) Direct capture with amorphous selenium photoconductor
D) None of these use TFTs

Question 29

The histogram is

A) the digital radiographic image
B) the electronic signal from the ADC
C) a graphic representation of a data set
D) the digital radiographic image and a graphic representation of a data set

Question 30

When processing the PSP plate, the analog signal is digitized and divided into a matrix of squares. Each square is a

A) detector element (DEL)
B) field of view (FOV)
C) picture element (pixel)
D) volume element (voxel)

Question 31

Histogram analysis compares the histogram with pre-established histograms specific to

A) the x-ray equipment
B) the computer monitor
C) the patient data
D) the anatomic part being imaged

Question 32

During image acquisition, the computer analyzes the histogram using:

A) algorithms
B) look-up-tables (LUT)
C) analog-digital-converter (ADC)
D) detective quantum efficiency (DQE)

Question 33

Part of a DR system with indirect capture, the light-sensitive device that is commonly found in digital cameras is the

A) charge-coupled device (CCD)
B) photoconductor
C) thin film transistor (TFT)
D) scintillator

Question 34

The two methods for indirect capture in DR include

A) charge-coupled devices
B) photoconductors and TFT arrays
C) scintillator and TFT array
D) charge-coupled devices and scintillator and TFT array

Question 35

The placement of several CCD detectors close together to form a larger detector is called

A) roofing
B) tiling
C) butting
D) none of these

Question 36

Amorphous silicon is used as the

A) photoconductor for indirect capture DR imaging
B) photodetector for indirect capture DR imaging
C) photoconductor for direct capture DR imaging
D) photodetector for direct capture DR imaging

Question 37

The scintillator for the indirect capture DR system that utilizes a CCD is

A) cesium iodide
B) barium fluorohalide
C) amorphous selenium
D) crystalline silicon

Question 38

Which of the following describes the extra step, and is therefore a limitation, of indirect-capture methods?

A) X-rays are converted to light and then to electrons
B) X-rays are converted directly to electrons
C) Electrons are converted to light, and then to x-rays
D) X-rays are converted to light and then to electrons and X-rays are converted directly to electrons

Question 39

In an indirect capture DR system, the electronic components that is configured in a network of detector elements is the

A) charge-coupled device (CCD)
B) photoconductor
C) thin film transistor (TFT)
D) scintillator

Question 40

The scintillator for the indirect capture DR system that utilizes a CMOS is

A) cesium iodide
B) barium fluorohalide
C) amorphous selenium
D) crystalline silicon

Question 41

Bit depth:

A) is the available grayscale
B) refers to the number of shades of gray that can be displayed within a pixel
C) is measured in microns
D) is the available grayscale and refers to the number of shades of gray that can be displayed within a pixel

Question 42

As compared with the H&D curve of film with the toe, straight-line portion, and shoulder, the response of a digital IR to exposure is

A) more curved
B) a straight line
C) a line and a curve
D) a curve but less than film

Question 43

The range of exposure intensities that an IR can respond to and acquire image data is

A) dynamic range
B) exposure range
C) brightness range
D) All of these

Question 44

For CR systems, the exposure index is based on

A) how much exposure leaves the x-ray tube
B) how much mAs was set at the operators console
C) the histogram analysis
D) the kVp being used

Question 45

The rate at which a data sample is acquired from the detector is the

A) sampling rate
B) sampling frequency
C) sampling pitch
D) bit depth

Question 46

Sampling pitch is

A) the distance between laser beam positions during processing of the plate
B) the distance between adjacent detector elements
C) how digital detectors sample the x-ray exposure
D) all of these

Question 47

As the pixel size decreases, the spatial resolution

A) increases
B) decreases
C) remains the same

Question 48

As the matrix size increases, the pixel size

A) increases
B) decreases
C) remains the same

Question 49

Which manufacturers use exposure indicators that are inversely related to the exposure to the digital detector?

A) Carestream
B) Fuji
C) Konica
D) Fuji and Konica

Question 50

Postprocessing functions

A) allow changes to be made in the appearance of the digital image
B) are done through computer software operations
C) include window width and window level adjustments
D) All of these

Question 51

The dynamic range of a digital imaging system is ____________ than that of a film-screen system

A) much less
B) much greater
C) approximately the same
D) a little bit greater

Question 52

Digital imaging preprocessing includes

A) rescaling
B) histogram analysis
C) rescaling and histogram analysis
D) none of these

Question 53

The range of exposures that produce acceptable information to be used in image formation is

A) exposure range
B) dynamic range
C) exposure latitude
D) bit depth

Question 54

The human eye can appreciate approximately _______ shades of gray at a particular level.

A) 5
B) 10
C) 30
D) 300

Question 55

As the matrix size decreases, the spatial resolution

A) increases
B) decreases
C) remains the same

Question 56

Which of the following is the correct sequence for extracting and processing the image with the PSP plate?

A) Signal sent to ADC; scanned by laser light; sampling of signal; converted to electronic signal
B) Converted to electronic signal; sampling of signal; signal sent to ADC; scanned by laser light
C) Scanned by laser light; converted to electronic signal; sampling of signal; signal sent to ADC
D) None of these

Question 57

Digital radiography uses a _____ dynamic range

A) 8-bit
B) 10-bit
C) 12-bit
D) 14-bit

Question 58

Primary workstation displays are used for

A) viewing the image for the first time
B) official image interpretation
C) viewing the digital image at the radiographer's console
D) All of these

Question 59

In CR, this represents the exposure level to the PSP plate

A) exposure indicator
B) dose-area product (DAP)
C) detective quantum efficiency (DQE)
D) dynamic range

Question 60

The useful imaging area of the digital receptor is the

A) detector element (DEL)
B) field of view (FOV)
C) thin-film transistor (TFT)
D) values of interest (VOI)

Question 61

Display device performance is determined by use of

A) a special imaging monitor
B) various test patterns
C) a variety of different types of image receptors
D) none of these

Question 62

The role of mAs in digital imaging includes

A) being the controlling factor of density
B) determining the quantity of radiation and patient dose
C) selecting optimum mAs to provide sufficient quanta to expose the receptor and avoid excessive noise
D) determining the quantity of radiation and patient dose and selecting optimum mAs to provide sufficient quanta to expose the receptor and avoid excessive noise

Question 63

If they have not been used for _______ hours, PSP plates should be erased

A) 4
B) 12
C) 24
D) 48

Question 64

This test assesses the displayed luminance values versus the input values from the display system

A) reflection
B) luminance response
C) luminance dependencies
D) resolution

Question 65

The primary factor influencing contrast with digital imaging is the

A) values of interest (VOI)
B) modulation transfer function (MTF)
C) lookup table (LUT)
D) detective quantum efficiency (DQE)

Question 66

DQE is

A) evaluated by comparing the image noise of a detector with that of an "ideal" detector with the same signal-response characteristics
B) a measure of how well the signal-to-noise ratio (SNR) is preserved in an image
C) the exposure necessary to produce a desired level of brightness
D) evaluated by comparing the image noise of a detector with that of an "ideal" detector with the same signal-response characteristics and a measure of how well the signal-to-noise ratio (SNR) is preserved in an image

Question 67

The value that indicates exposure to the IR with a DR imaging system is the

A) exposure indicator
B) dose-area product (DAP)
C) detective quantum efficiency (DQE)
D) dynamic range

Question 68

Having a higher DQE indicates a potentially

A) lower patient dose
B) higher patient dose
C) similar patient dose

Question 69

The ideal expression of digital detector image resolution is the

A) Nyquist frequency
B) modulation transfer function (MTF)
C) limiting spatial resolution (LSR)
D) detective quantum efficiency (DQE)

Question 70

__________ allows for the acquisition, display, and storage of digital images

A) PACS
B) DICOM
C) teleradiology
D) RIS

Question 71

Digital imaging quality control focuses on

A) the display monitors
B) the viewing environment
C) the radiologist's comfort
D) the display monitors and the viewing environment

Question 72

What would the DQE measure if the imaging system has 100% conversion efficiency?

A) 0
B) 0.5
C) 1.0
D) 2.0

Question 73

Because digital systems are more sensitive to low-energy radiation, how can scatter radiation be effectively controlled?

A) Pre-exposure collimation
B) Post-processing masks
C) Use of a grid
D) Pre-exposure collimation and use of a grid

Question 74

The highest spatial frequency that a digital detector can record is the

A) Nyquist frequency
B) modulation transfer function (MTF)
C) limiting spatial resolution (LSR)
D) detective quantum efficiency (DQE)

Question 75

One half of the Nyquist frequency is equal to

A) the spatial resolution of a digital system
B) the contrast resolution of a digital system
C) the amount of noise in a digital system
D) the detective quantum efficiency (DQE)

Question 76

This test assesses the system's ability to display images of different parts of an image with high fidelity

A) reflection
B) luminance response
C) luminance dependencies
D) resolution

Question 77

The ability of a detector to resolve small structures is the

A) Nyquist frequency
B) modulation transfer function (MTF)
C) limiting spatial resolution (LSR)
D) detective quantum efficiency (DQE)

Question 78

Related to the DR detector,______________ is an expression of the radiation exposure level that is required to produce an optimal image.

A) exposure indicator
B) dose-area product (DAP)
C) detective quantum efficiency (DQE)
D) target exposure index

Question 79

Undesirable fluctuations in the brightness of an image is

A) contrast
B) noise
C) DQE
D) DAP

Question 80

If the DQE is too high

A) the image will be very noisy/grainy
B) the image will be very dark
C) the image will be very light
D) the patient dose will be too high as well