sensor problems

Question 1

sensor placement and beam positioning problems related to
image receptor:

Answer 1

a. film
b. PSP (phosphor storage plate)
c. charged coupling device (CCD)
d. complementary metal oxide semiconductor (CMOS)

Question 2

sensor placement and beam positioning problems related to
shadow casting principles

Answer 2

a. beam angulation
c. receptor placement

Question 2

sensor placement and beam positioning problems related to
human element

Answer 2

a. clinician
b. patient
c. a and b

Question 3

3 sensor placement and beam positioning problems

Answer 3

1. miscellanous technique problems
2. exposure problems
3. patient preparation problems

Question 4

miscellaneous technique problems

Answer 4

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 [just PSP and film!]
9. sensor creasing
10. double exposure
11. reversed placement [just PSP and film!]

Question 5

pt finger positioned in front of sensor

Answer 5

phalangioma

Question 6

patient or x-ray tube head moves during exposure

Answer 6

movement

Question 7

sensor palcement is MORE critical with

Answer 7

solid state sensors

Question 8

with sensors, there is a ____active image capture area

Answer 8

smaller

Question 9

maxillary premolar PA requirements

Answer 9

• Receptor parallels B and L planes of premolars
• Receptor parallels long axis of
  premolars
• 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

Question 10

maxillary molar PA requirements

Answer 10

Receptor parallels B and Li
planes of molars
* Receptor parallels long axis
of molars
* 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

Question 11

premolar bitewing requirements

Answer 11

Receptor parallels B and Li
planes of premolars
* Receptor parallels long axis of
premolars
* 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

Question 12

cotton roll placement:

Answer 12

between biteblock and opposing teeth; NOT between biteblock and imaged teeth

Question 13

two examples of incorrect placement

Answer 13

1. absence of apical structures
2. dropped sensor corner

Question 14

cause of absence of apical structures

Answer 14

-sensor not positioned over apical area in mouth
-bite block not against occlusal/incisal edge
OR patient not biting down

Question 15

cause of “tipping” aka dropped film corner

Answer 15

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

Question 16

incorrect horizontal angulation

Answer 16

beam angulation horizontal
-dont want overlapping: want to see interproximals

(anterior and posterior bitewing placements)

Question 17

with horizontal angle, the central ray should be directed between

Answer 17

interproximal contacts of interest

and
projected perpendicular to sensor

Question 18

incorrect horizontal angulation caused by

Answer 18

central ray is not projected perpendicular to sensor

Question 19

(looking at fence straight on, between the wood pickets are open)

Answer 19

mesial to distal

Question 20

(looking at the fence from right to left, the spaces get narrower the farther left one looks

Answer 20

distal to mesial

Question 21

move (m/d) to (m/d)

Answer 21

move mesial to distal
KNOW

Question 22

two examples of beam angulation vertical

Answer 22

1. foreshortened images
2. elongated images

(distortion)

Question 23

cause of foreshortened images

Answer 23

(shortening the image)
1. excessive vertical angulation
2. beam is perpendicular to the sensor
3. with smaller active area, parts of image are missed

Question 24

the sensor placement is MORE critical with solid-state sensors, BUT with a smaller active image capture area AND long roots=

Answer 24

foreshortening is encouraged!

Question 25

cause of elongated images

Answer 25

1. insufficient vertical angulation 2. beam is perpendicular to the tooth

Question 26

point up: foreshorterning pointing down: elongation ???? idk he said this in lecture

Question 27

BID/PID alignment problems

Answer 27

cone cuts: 1. with sensor holder 2. without sensor holder

Question 28

PID alignment problems with cone cuts with sensor holder cause

Answer 28

-PID not properly aligned with the sensor holding device from: 1. incorrect XCP assembly 2. poor alignment of PID with XCP

Question 29

PID alignment problems with cone cuts without sensor holder (XCP) cause

Answer 29

PID not directed at center of film

Question 30

II: exposure problems:

Answer 30

1. overexposed 2. underexposed 3. no exposure 4. sensor wire superimposition 5. post exposure

Question 31

what exposure problems are less dramatic because post-exposure image processing by the software immediately corrects large exposure

Answer 31

1. overexposed 2. underexposed

Question 32

overexposed =

Answer 32

HIGH density image a. increased time b. increased mA c. increased kV all contribute to being too dark

Question 33

causes excessive exposure to x-radiation from excess time, kVp, mA, or any combo of these

Answer 33

overexposed images

Question 34

cause insufficient exposure time, kVP, mA, or any combo of these -in SoF radiology, ____is the main cause

Answer 34

underexposed image TIME

Question 35

underexposed:

Answer 35

1. insufficient -time -mA -kVp excessive tube-receptor distance; released to INVERSE SQAURE LAW

Question 36

excessive tube-receptor distance; released to INVERSE SQAURE LAW

Answer 36

underexposed

Question 37

faulty program software image setting: calibration files

Answer 37

exposure problems: post exposure image processing

Question 38

faulty program software image settings: + gain, gamma, -gam

Answer 38

gain: adjusts bright tones and brings more information into the highlights of an image gamma correction: adjusts midtones of an image by adjusting each pixel value in an image. usually performed automatically on a PC monitor, but the precision is adjustable

Question 39

failure to remove a non-fixed item from patient that may be in path of the primary xray beam

Answer 39

patient preparation problem

Question 40

patient preparation problem examples

Answer 40

eyeglasses frame RPD left in mouth gum or candy piercing

Question 41

what happens if dont remove jewelry

Answer 41

risks masking disease