Digital Radiography and PACS Chapters 1-3
1. Digital Imaging
Any imaging acquisition process that produces an electronic image that can be viewed and manipulated on a computer
2. Direct Capture digital Radiography
Devices convert the incident x-ray energy directly into an electrical signal. typically using a photo- conductor as the x-ray absorber, and send the electrical signal to a TFT and then to a ADC.
3. Flat panel detector (FPD)
Detector that consists of a photoconductor, which holds a charge on its surface that can be read out by a thin-film transistor.
4. Indirect capture digital radiography
Devices absorb x-rays and convert them into light. The light is then collected by an area-ccd or thin - film transistor (TFT) array and then converted into electrical signal that is sent.
5. Photostimulable phosphor (PSP) Image capture
Digital acquisition modality that uses storage phosphor plates to produce projection images.
moving images via telephone lines to and from remote locations.
7. Air Kerma
Kinetic energy released per unit mass; measures (in joules) radiation energy that is absorbed in unit of air.
Level of intensity of a digital image displayed monitor.
9. Contrast resolution
ability of a digital system to display changes in grayscale values
10. Detective quantum efficiency (DQE)
Measurement of how efficiently a system converts an x-ray input signal into a useful output image.
11. Deviation index (DI)
The difference between actual exposure and target exposure expressed as a logarithm.
12. Dynamic Range
The ability of an imaging system to respond to varying levels of exposure.
13. Indicated equivalent air kerma (kind)
Measurement of radiation incident on the image receptor derived from pixel values produced by the exposure to an image receptor.
Amount of error that can be made in exposure factor choice and still result in capture of a quality image.
rectangular or square table of numbers that represent the pixel intensity to be displayed on the monitor.
16. Modulation transfer function (MTF)
Ability of a system to record available spatial frequencies.
Any type of signal interference in a digital image.
18. Noise power spectrum (NPS)
Spatial frequency content and spatial characteristics of noise.
basic picture element on a display.
20. Pixel bit depth
The number of bits within a pixel
21. Signal-to-noise-ration (SNR)
The ratio of the amount of total signal versus the amount of noise present in any digital image.
22. Spatial resolution
The ability of the imaging system to demonstrate small details of an object.
23. Standardized radiation exposure (KSTD)
Standard exposure typical of an imaging receptor system that is made with additional filtration to simulate patient tissue.
24. Target equivalent air kerma value (KTGT)
A set of established values that represent optimal exposure for each specific body part and view.
Loss of digital information because of fluctuating signal; aka foldover, biasing, or wraparound.
26. Archiving query
Software function that allows historical information to be gathered from digital storage, such as multiple exams, a range of dates, or pathology.
27. Automatic rescaling
occurs when exposure is greater or less than the optimal amount to produce a diagnostic image; it is the effort of the computer to "fix" exposure errors.
28. Contrast manipulation
conversion of the digital image using contrast enhancement parameters.
29. Critical frequency
The frequency that exactly matches the Nyquist frequency resulting in a zero - amplitude signal caused by phase shift.
30. Edge enhancement
Enhancement occurs when fewer pixels in the neighborhood are included in the signal average; the smaller the neighborhood, the greater the enhancement.
31. High - pass filtering
technique for the enhancement of contrast and edge that amplifies the frequencies of areas of interest that are known and suppresses frequencies outside the area of interest.
Graphic representation of all digital recorded signals of a digital x-ray exposure.
33. Image annotation
Software function that allows text or markers to be digitally added to an image.
34. Image Orientation
Identification of the top or side of an image.
35. Image Sampling
Amount of information gathered from pixel storage.
36. Image stitching
the process of sewing together multiple images to form one continuous image.
37. Look-up table (LUT)
reference histogram of the luminance values derived during image acquisition.
38. Low-pass filtering
result of averaging each pxiel frequency with surronding pixels values to remove high-frequency noise and contrast; useful for viewing small structures such as fine bone.
39. Manual send
computer function that allows images to be sent to specified reading stations.
40. Nyquist theorem
When sampling a signal such as the conversion from an analog to digital image, the sampling frequency must be greater than twice the bandwidth of the input signal so that the reconstruction of the original image will be nearly perfect.
41. Patient demographics
input information regarding patient age, identifying number, ordering physician, and so on.
used ti blacken out the white collimation borders in a digital image, effectively eliminating veil glare.
Aka low-pass filtering, the result of averaging each pixel's frequency with surrounding pixel values to remove high frequency noise.
44. Spatial frequency
amount of detail or sharpness in a digital image.
45. Window level
image manipulation parameter that changes screen image brightness, usually through the use of a mouse.
46. Window width
image manipulation parameter that changes screen image contrast, usually through the use of a mouse.
47. Which company was the first to introduce PSP imaging commercially in the US
48. Which radiographic image capture method uses an x-ray absorber material coupled to a thin film transistor or a change - coupled device (CCD) to form the digital radiographic image.
49. When x-rays strike a photostimulable phosphor material ___ is released.
50. The exposure latitude of digital projection radiography responds in a linear or Nonliner
51. PACS stands for
Picture archiving and communication system
52. In what format must images be in so that they can be sent throughout the image viewing system?
53. True or False: Patient demographics are unimportant because the RIS will automatically identify all digital images.
54. True or False: Digitally placed anatomic markers can always be used to determine the correct anatomic side of the patient.
55. Digital systems are less sensitive to scatter radiation than film/screen systems.
56. An image formed by recording a continuously changing signal is known as
57. The arrangement of pixels in rows and columns is known as
58. The amount of tissue included in the image is referred to as
Field of view
59. Contrast resolution is a digital systems ability to?
show small differences in gray levels
60. True or False: Dynamic range is the ability of a digital imaging system to respond to varying levels of exposure
61. True or False: Spatial resolution in digital imaging is dependent on pixel size
62. True or False: The best component in a digital system will determine the resolution in a digital image
63. Which measures the efficiency of a system to convert the x-ray input signal into a useful output image.
64. A graphical representation of a digital image is called
65. The useful signal is determined during what part of the imaging processing?
66. True or False: The Nyquist theorem states that the sampling frequency must be less than twice
67. True or False: Aliasing occurs when the sampling frequency is not greater than twice the frequency of the input signal
68. In digital projection radiography, what process is used to normalize an image that has been taken with too great of an exposure
69. True or False: The look-up table that is used to determine the brightness and contrast of an image is unique for each atomic part
70. True or False: Window width controls brightness of the image on the display
71. True or False: Shuttering the digital image will reduce the exposure to the patient.
72. What processing parameter will put together multiple images into one single image for display?