PSPP Sensor Placement and Beam Positioning Problems Flashcards
Sensor placement and beam positioning problems can be caused by…
- 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) - shadow casting principles
a. beam angulation
b. receptor placement - The “Human” element
a. clinician
b. patient
What are the miscellaneous technique problems?
- Phalangioma
- Movement
- Sensor placement
- Beam angulation - Horizontal
- Beam angulation - Vertical
- PID/BID alignment
- Sensor wire placement
- Sensor bending
- Sensor Creasing
- Double exposure
- Reversed placement
(8-11 PSP and film only)
What is phalangioma?
Patient’s finger positioned in front of the sensor
What is wrong with this image?
phalangioma
What is wrong with this image?
phalangioma
What is the problem with movement during x-rays?
Patient or x-ray tube head moves
during exposure
What is wrong with this image?
movement
Sensor placement is _____ critical with solid-state sensors
MORE
Why is sensor placement more critical with solid-state sensors?
smaller active image capture area
Where do you place the receptor for a maxillary premolar PA?
- 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
Where do you place the receptor for a maxillary molar PA?
- 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
What type of x-ray is this?
maxillary molar PA
What type of x-ray is this?
maxillary premolar PA
Where do you place the receptor for a premolar bitewing?
- 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
What type of x-ray is this?
premolar bitewing
Where do you put the cotton roll for x-rays?
Between biteblock and opposing teeth
T/F: put the cotton roll between biteblock and imaged teeth
False!
- Between biteblock and opposing teeth
What are ways you can have incorrect placement?
- Absence of apical structures
- Dropped sensor corner
What can cause an absence of apical structures from an x-ray?
- Sensor not positioned over the apical area in the mouth
- Bite block not against occlusal/incisal edge; OR patient not biting down
What is wrong with this image?
- Incorrect Sensor Placement
- Absence of apical structures
What is the cause of the “tipping”/dropped film corner?
Sensor not placed parallel with the occlusal / incisal surface of teeth
How do you set the horizontal angle?
The Central Ray should be directed between the interproximal contacts of interest
Central ray has to be projected _______________ to sensor
perpendicular
Is this incorrect horizontal angulation mesial to distal or distal to mesial?
Mesial to distal
Is this incorrect horizontal angulation mesial to distal or distal to mesial?
distal to mesial
What can issues with beam angulation vertical cause?
- Foreshortened images
- Elongated images
What is the cause of foreshortened images?
- Excessive vertical angulation
- Beam is perpendicular to the sensor (but object not parallel to receptor?- haley)