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Oral Radiology > Sensors & Digital Imaging (Lec 6) > Flashcards

Sensors & Digital Imaging (Lec 6) Flashcards

1
Q

List the reasons to change from traditional to digital imaging: (7)

A
  1. significantly less radiation
  2. better image
  3. lower cost (more net income)
  4. environmentally friendly (less toxic chemicals are disposed into the sewage systems)
  5. electronic communication improves efficiency
  6. rapid acquisition
  7. image portability (storage, transmission, duplication)

Others- eliminates need for film, processing, dark room set-up, chemicals, and therefore increases workflow and efficiency

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2
Q

Image created when the photons break up the silver halide crystals and the bromine and fluorine crystals float around and create an image based on how their energy was changed:

A

film image

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3
Q

Chemical changes in processing occurs with what type of image?

A

film image

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4
Q

Image created when the shadow created by the object being captured is transferred to electrical charges that are assigned a numerical value by the computer which is then converted to a certain color of grey and an image is created:

A

digital image

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5
Q

The general steps in digital image formation include: (4)

A
  1. X-ray shadow
  2. shadow image detected by digital sensor
  3. numerical pixel values sent to the computer
  4. digital image displayed on computer screen
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6
Q

In the first step of digital image formation, the shadow (x-ray shadow) is created by:

A

An object

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7
Q

In the second step of digital image formation (shadow image detected by digital sensor) the pixels are _____. Each pixel has a ____ charge

A

electrified; pre-exposure electrical charge

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8
Q

In the second step of digital image formation (shadow image detected by digital sensor) X-ray photons that make it to the sensor change the ____ in those pixels

A

electric charge

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9
Q

In the second step of digital image formation (shadow image detected by digital sensor), the thicker/dense the body part:

A

The less x-photons can affect the electrical charge

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10
Q

In the second step of digital image formation (shadow image detected by digital sensor) what is the overall net effect?

A

There is a shadow of electric charges on the sensor relative to the thickness/density of the body part

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11
Q

In the third step of digital image formation (numerical pixel values sent to the computer), the electric charge value of each pixel is converted to a:

A

Numerical value (digitized)

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12
Q

In the third step of digital image formation (numerical pixel values sent to the computer), ______ is sent to the computer for further processing

A

pixel value

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13
Q

In the fourth step of digital image formation (digital image displayed on the computer screen), the computer assigns a ____ to each number

A

Gray value

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14
Q

In the fourth step of digital image formation (digital image displayed on the computer screen), the gray values are displayed:

A

In a visual

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15
Q

Pixel is derived from the words:

A

PEL (picture element)

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16
Q

the smallest portion of a sensor, image or display that is capable of being recorded and then printed or displayed:

A

Pixel (Px)

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17
Q

Each pixel is assigned a ____ and then translated to a ____

A

numerical value; specific shade of gray

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18
Q

Image quality:

A

Spatial resolution

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19
Q

The smaller the pixel, the ____ the will be

A

sharper/better resolution

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20
Q

The smaller the pixel, the ______ the processing time

A

longer

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21
Q

Digital has a ____ pixel size compared to film

A

Larger

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22
Q

ability of the display/computer to distinguish between differences in color intensity:

A

Contrast resolution

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23
Q

Number of gray shades that a pixel is able to display:

A

Bit depth

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24
Q

What affect does bit depth have on contrast resolution?

A

an increase in bit depth –> decreases contrast resolution

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25
Q

2^(BIT) =

A

Shades of gray visible

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26
Q

if the bit is 3 then how many shades of grey are visible?

A

2^3 = 8 shades

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27
Q

List the different ways of digital image acquisition: (3)

A
  1. indirect/hybrid
  2. digital indirect (semidirect)/computed radiography
  3. digital direct/digital radiography
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28
Q

Digital indirect image acquisition may be considered:

A

semidirect or computed radiography

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29
Q

Digital direct image acquisition may be considered:

A

digital radiography

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30
Q

What form of digital acquisition is being described:

-Slide scanner, flatbed scanner, film, digital camera

A

Indirect/hybrid

31
Q

What form of digital acquisition is being described:

-Phosphor storage plate (PSP)

A

Digital indirect (semidirect) (computed radiography)

32
Q

What form of digital acquisition is being described:

  • charge-coupled device (CCD)
  • Complementary metal oxide semiconductor (CMOS)
A

Digital direct (digital radiography)

33
Q

PSP:

A

Phosphor storage plate

34
Q

CCD:

A

Charge-coupled device

35
Q

CMOS:

A

Complementary metal oxide semiconductor

36
Q

Label the following components of a CCD sensor:

A

Top arrow: cable side housing + cable
Magenta: electronic substrate
Purple: CMOS imaging chip
Clear: fiber optic face plate (FOP)
Green: CSI scintillator
Black: front side housing

37
Q

List the steps involved in the functioning of CCD sensors:

A
  1. Celsium iodide scintillator converts x-rays into visible light
  2. Photosensitive pixels convert scintillator’s light into electrical signals. On-chip circuitry turns electrical signals into digital output
  3. Digital data is sent to computer
38
Q

In the first step in the functioning of CCD sensors, celsium iodine scintillaror converts ____ into ____

A

X-rays into visible light

39
Q

In the second step in the functioning of CCD sensors, ______ convert scintillator’s light into ____

A

Photosensitive pixels; electrical signals

40
Q

In the second step in the functioning of CCD sensors, the on-chip circuitry turns electrical signals into:

A

Digital output

41
Q

In the third step in the functioning of CCD sensors, digital data is sent to:

A

a computer

42
Q

CCDs have _____ radiation than CMOS

A

Less

43
Q

In CCD/CMOS digitization, X-ray photons cause ____ of _____ and the ejected electrons are trapped in a pixel in a similar fashion to the charge of a batter

A

Ionization; silicone

44
Q

In CCD/CMOS digitization, X-ray photons cause ionization of silicone and the ejected electrons are trapped in a pixel in a similar fashion to the charge of a battery.

The computer then calculates the ____ in each pixel and converts it to a value which is then converted to a ____

A

Charge; scale of grey

45
Q

Solid state sensors include:

A

CCD & CMOS

46
Q

Solid state sensors (CCD/CMOS) use _____ material

A

scintillating material

47
Q

“each pixel is like a tiny battery with its charge equal to the number of electrons trapped inside. The computer records the charge in each pixel and converts it to a gray value”

This is simplified explanation for:

A

CCD/CMOS digitization

48
Q

Inherent problems associated with CCD sensors include:

A
  1. Older technology takes longer because each row of pixels is read sequentially
  2. CCD is more expensive and consumes more power and requires adjunct box to convert from analog to digital
49
Q

Describe the CMOS structure and how its different from CCD:

A

Very similar to CCD, EXCEPT the photon to electron conversion and electron to voltage conversion occur within each individual pixel so its much quicker and does NOT require an adjunct box

50
Q

If we say “much quicker and does NOT require an adjunct box” we are describing:

A

CMOS

51
Q

What are some CMOS pros (over CCD):

A
  1. newer technology
  2. faster
  3. requires less power
  4. superior image quality
52
Q

What is faster? CMOS or CCD?

A

CMOS

53
Q

What has superior image quality? CMOS or CCD?

A

CMOS

54
Q

Which requires less power? CMOS or CCD?

A

CMOS

55
Q

PSP plates are coated with ______ (europium doped barium fluorobromide) which produces a ____ when these phosphors are ____

A

Crystalline halide emulsion; latent image; ionized

56
Q

What are PSP plates coated with:

A

Crystalline halide emulsion

57
Q

Describe the steps in PSP functioning:

  1. ____
  2. PSPS plates are coated with crystalline halide emulsion which:
  3. Scanned with:
  4. Emits ___ from ____ in ionized fluorophores
  5. intensified by a ____
  6. Light intensity is converted to:
  7. Expose plate to strong light to erase images by:
  8. ____
A
  1. X-rays
  2. Produces a latent image when these phosphors are ionized
  3. red laser beam
  4. fluorescent light; excitation of valence electrons
  5. photomultiplier tube
  6. digital data
  7. neutralizing charge in ionized fluorophores
  8. reuse
58
Q

What are some advantages to PSP plates: (4)

A
  1. reusable
  2. once digitized can be viewed and sent anywhere
  3. storage takes up less space than film
  4. processing is easier than film (but has physical similarities to film)
59
Q

Although processing of PSP plates is easier than film, there are ____ to film

A

Physical similarities

60
Q

Which is describing PSP plates? Which is describing CCD sensors?

  1. is a direct digital system where the image is taken and then shows up directly on the computer
  2. Requires a plate transfer box due to light sensitivity
  3. Requires a scanner before they are able to be viewed on the computer
A
  1. CCD
  2. PSP
  3. PSP
61
Q

What are the two main parts of sensors: (CCD/CMOS)

A
  1. external size
  2. internal active area
62
Q

The portion of the sensor (CCD/CMOS) that is producing the image:

A

Internal active area

63
Q

post-display mathematical algorithms that manipulate the digital signal:

A

Imaging manipulations (enhancements)

64
Q

Imaging manipulations include: (7)

A
  1. edge enhancement (sharpening)
  2. noise reduction (softening)
  3. optimizing of density/contrast
  4. inversion of gray scale
  5. magnification
  6. emboss function
  7. pseudocolor enhancement
65
Q

Edge enhancement may also be considered:

A

Sharpening

66
Q

Noise reduction may also be considered:

A

Softening

67
Q

____ and ____ adjustments are done together to find the best combination to highlight the clarity of the structures

A

Brightness & contrast

68
Q

What do the circled buttons mean?

A

Blue: undo
Purple: redo

69
Q

What does the circled button mean?

A

Reset

70
Q

What do the circled buttons mean?

A

Pink: rotate 90 degrees
Purple: show/hide ~ brightness/contrast
Green: show/hide ~ histogram

71
Q

What do the circled buttons mean?

A

Purple: noise reduction
Pink: edge enhancement “sharpened”
Blue: Magnifier

72
Q

What do the circled buttons mean?

A

Orange: zoom
Blue: fit to frame
Purple: fit image to screen resolution (best)

73
Q

What do the circled buttons mean?

A

Pink: measurement calibration
Blue: ruler
Green: multi-line ruler

74
Q
A

Oral Radiology (21 decks)

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