Module 22 Flashcards
What extra-oral film is most commonly prescribed?
Panoramic
A panoramic x-ray is used to _______ other x-rays?
supplement
Panoramic x-rays are great for examining _____ teeth, ____ patterns, MX/MN ______ and detect __ and __ or the jaws?
impacted
growth/eruption
trauma
diseases/lesions
Panoramic x-rays are not as _____ or ____ as PA’s/BWX?
defined
sharp
Should Panoramic x-rays be used to evaluate caries, perio, or periapical lesions?
No
In panoramic imaging the _ and ___ move around the patient?
receptor
tubehead
The x-ray tube rotates the same direction as the receptor? T/F
False
The movement of the tube head and receptor produces an image through what process?
tomography
The rotation center is what?
pivotal point/axis, around which the receptor and tubehead rotate
What are the 3 rotation centers
doubel-center
tripple-center
Moving-center
_______ influence the size and shape of the focal trough?
rotational centers
The focal trough is also known as?
image layer
Define the focal trough?
3 dimensional curved zone where structures are clearly demonstrated
The _____ the rotation center to teeth, the _ the focal trough?
closer
narrower
Quality of a Panoramic x-ray depends on?
position of pt.s teeth within focal trough
What equipment is used to take a panoramic x-ray?
Unit
Receptor
Film
Cassette with intensifying screen
The main components of a panoramic unit are?
tubehead
head positioner
exposure controls
The collimator used in the panoramic x-ray machine is a ___ plate with an opening in the shape of a _____ with _____size opening?
lead
narrow vertical slit
2x30mm wide
The tube head rotates in front of the patients head, the receptor rotates in back of the patient T/F?
False- opposite
Intensifying screens convert x-rays into?
light
What size films are used in Panoramic imaging?
5x12
6x12
What are the 2 types of intensifying screens? Which one is used most?
Calcium tungstate
Rare earth
Rare earth
Which intensifying screen is sensitive to green light?
Rare Earth
The patients midsagital plane should be _____ to the floor?
perpendicular
The Frankfort plane should be _____ to the floor?
parallel
T/F You should always use a lead apron with a thyroid collar when taking Pano films?
False
If the patients lips are not closed what happens to the pano film?
dark radiolucent shadow obscures anterior teeth
If the chin is tilted up too far what happens to the image?
MX incisors are blurred
Reverse smile line :(
If the chin is tilted down too far what happens to the image?
MN incisors are blurred
exaggerated smile line :)
What is wrong with PT positioning if the anterior teeth look “skinny”?
too far forward on bite block
If the patient’s teeth are aligned too far back on the bite-block what happens to the image?
teeth appear “fat” and out of focus
What happens if the patient isn’t standing up tall?
spine superimposes over anterior teeth
Advantages of Panoramic x-rays?
Field Size
Simplicity
Less exposure to x-rays
pt. cooperation is high
Disadvantages of Panoramic x-rays?
Quality
Focal trough limitations
distortion
Cost of equipment
The term focal trough is a _____ concept?
theoretical
The size and shape of the focal trough is determined by?
Manufacturer
T/F You get more exposure to x-rays when doing a pano than with 4BWX?
False
What happens if the patient doesn’t keep their tongue up to the roof of the mouth?
Radiolucent shadow over apices of MX
What information do you put on the label for a panoramic x-ray?
Last name, first name, date, clinic number
