PSPP Sensor Placement and Beam Positioning Problems Flashcards

1
Q

Sensor placement and beam positioning problems can be caused by…

A
  1. image receptor
    a. Film
    b. Photostimulable Phosphor Plate (i.e., PSPP)
    c. Charge Coupling Device (i.e., CCD)
    d. Complimentary Metal Oxide Semiconductor (i.e., CMOS)
  2. shadow casting principles
    a. beam angulation
    b. receptor placement
  3. The “Human” element
    a. clinician
    b. patient
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the miscellaneous technique problems?

A
  1. Phalangioma
  2. Movement
  3. Sensor placement
  4. Beam angulation - Horizontal
  5. Beam angulation - Vertical
  6. PID/BID alignment
  7. Sensor wire placement
  8. Sensor bending
  9. Sensor Creasing
  10. Double exposure
  11. Reversed placement
    (8-11 PSP and film only)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is phalangioma?

A

Patient’s finger positioned in front of the sensor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is wrong with this image?

A

phalangioma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is wrong with this image?

A

phalangioma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the problem with movement during x-rays?

A

Patient or x-ray tube head moves
during exposure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is wrong with this image?

A

movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Sensor placement is _____ critical with solid-state sensors

A

MORE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why is sensor placement more critical with solid-state sensors?

A

smaller active image capture area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where do you place the receptor for a maxillary premolar PA?

A
  • Anterior edge of receptor includes distal ½ of canine, the premolars and some of molars
  • Horizontal angle directed through distal of canine/premolar, premolar/premolar, and the 2nd premolar/ molar contacts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where do you place the receptor for a maxillary molar PA?

A
  • Anterior edge of receptor includes distal ½ of 2nd premolar and as much of the molars as possible
  • Horizontal angle directed through distal of 2nd premolar/1st molar and the intermolar contacts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What type of x-ray is this?

A

maxillary molar PA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What type of x-ray is this?

A

maxillary premolar PA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where do you place the receptor for a premolar bitewing?

A
  • Anterior edge of receptor includes mesial ½ of canine, the premolars and some of molars
  • Horizontal angle directed through distal of canine/premolar, premolars and the 2nd premolar/ 1st molar contacts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What type of x-ray is this?

A

premolar bitewing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where do you put the cotton roll for x-rays?

A

Between biteblock and opposing teeth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

T/F: put the cotton roll between biteblock and imaged teeth

A

False!

  • Between biteblock and opposing teeth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are ways you can have incorrect placement?

A
  • Absence of apical structures
  • Dropped sensor corner
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What can cause an absence of apical structures from an x-ray?

A
  • Sensor not positioned over the apical area in the mouth
  • Bite block not against occlusal/incisal edge; OR patient not biting down
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is wrong with this image?

A
  • Incorrect Sensor Placement
  • Absence of apical structures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the cause of the “tipping”/dropped film corner?

A

Sensor not placed parallel with the occlusal / incisal surface of teeth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do you set the horizontal angle?

A

The Central Ray should be directed between the interproximal contacts of interest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Central ray has to be projected _______________ to sensor

A

perpendicular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Is this incorrect horizontal angulation mesial to distal or distal to mesial?

A

Mesial to distal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Is this incorrect horizontal angulation mesial to distal or distal to mesial?

A

distal to mesial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What can issues with beam angulation vertical cause?

A
  • Foreshortened images
  • Elongated images
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the cause of foreshortened images?

A
  • Excessive vertical angulation
  • Beam is perpendicular to the sensor (but object not parallel to receptor?- haley)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the issue with this image?

A

foreshortened image

29
Q

What is the issue with this image?

A

foreshortened image

30
Q

When you foreshorten an image with smaller active area what happens?

A

parts of the image are missed

31
Q

What is wrong with the image on right compared to the “good” one of the left

A

foreshortened image

32
Q

With a smaller active image capture area AND long roots _____________ is encouraged

A

foreshortening

33
Q

What causes elongated images?

A
  • Insufficient vertical angulation
    – Beam is perpendicular to the tooth/teeth
34
Q

What is the issue with this image?

A

elongated images

35
Q

What is the issue with this image?

A

elongated images

36
Q

What does BID/PID alignment problems cause?

A
  • Cone cuts
    – With sensor holder
    – Without sensor holder
37
Q

What is BID/PID?

A

beam indicating device
position indicator device

38
Q

What is the cause of cone cuts with sensor holder?

A

PID not properly aligned with the sensor holding device from
- incorrect XCP Assembly
- poor alignment of PID with XCP

39
Q

What is the issue with this image?

A

PID ALIGNMENT PROBLEMS

40
Q

What is the issue with this image?

A

PID ALIGNMENT PROBLEMS

41
Q

What causes cone cuts without sensor holder (XCP)?

A

PID not directed at center of film

42
Q

What is wrong with this image?

A

sensor wire

43
Q

What is wrong with this image?

A

sensor wire

44
Q

What are exposure problems?

A
  1. Overexposed
  2. Underexposed
  3. No exposure
  4. Sensor wire superimposition
  5. Post exposure
45
Q

Why are overexposed and underexposed images not as big of a deal?

A

post-exposure image processing by the software immediately corrects large exposure discrepancies

46
Q

What causes overexposed images?

________ time
________ mA
________ kV

A

increased time
increased mA
increased kV

47
Q

An overexposed image has ____ density

A

high

48
Q

What causes overexposed images?

A

Excessive exposure to x-radiation from excess time, kVp, mA, or any combination of these

49
Q

What is wrong with this image?

A

overexposed

50
Q

What is wrong with this image?

A

overexposed

51
Q

What is wrong with this image?

A

underexposed

52
Q

What causes an underexposed image?

A

Insufficient exposure time, kVp, mA, or any combination of these

53
Q

What causes underexposed images?

________ time
________ mA
________ kVp

A

insufficient time
insufficient mA
insufficient kVp

54
Q

Excessive tube-receptor distance is related to…

A

inverse square law

55
Q

What is post exposure image processing issues?

A
  • Faulty program software image settings: calibration files

+ gain, gamma, - gain

56
Q

What is gain for image processing?

A

Adjusts the bright tones and brings more information into the highlights of an image.

57
Q

What is gamma correction for image processing?

A

Adjusts the midtones of an image by adjusting each pixel value in an image. It is usually performed automatically on a PC monitor, but the precision is adjustable

58
Q

What is wrong with this image?

A

Post Exposure Image Processing

59
Q

What are examples of failure to remove a non-fixed item from patient that may be in path of the primary x-ray beam?

A

gum, candy, piercings, eyeglass frames, et cetera

60
Q

What causes sensor bending?

A

Sensor is bending toward source because of impingement against palate

61
Q

What causes sensor creasing/scratch marks?

A

damage to storage phosphors so there is no signal to the area with damaged pixels

62
Q

What is wrong with this image?

A

sensor creasing/scratch marks

63
Q

What is wrong with this image?

A

sensor bending

64
Q

What is a double exposure?

A
  • Sensor is accidentally exposed
    twice
    – Not possible with contemporary CMOS capture software
65
Q

What is wrong with this image?

A

double exposure

66
Q

What is wrong with this image?

A

double exposure

67
Q

What is the cause of reversed placement?

A

Sensor is placed back to front in sensor holder

– Unlikely with contemporary CMOS sensors because of poor unstable fit in biteblock

68
Q

What is wrong with this image?

A

Reversed Placement