Panoramic Imaging Principles Flashcards
What are the indications for panoramic radiography? (7)
(Evaluation of)
1. overall dentition
2. interosseous pathology (cysts, tumors, etc.)
3. TMJ
4. position of 3rd molars
5. dental development & eruption
6. denomaxillofacial trauma
7. developmental disturbances or syndromes
List the advantages of panoramic radiography: (6)
- Relatively low radiation dose (compared to FMX)
- Broad coverage of facial bones and teeth
- Easier technique
- Can be used in patients with truisms or in patients who cannot tolerate intraoral radiographs (more comfortable & faster)
- Quick and convenient radiograph technique
- Useful visual aid in patient education
List the disadvantages of panoramic radiography: (6)
- Lower resolution areas (not able to detect small carious lesions or early periodontal disease)
- Overlap in premolar area
- Magnification across image is unequal making linear measurements unreliable
- Image superimposition of real, double, and ghost images
- Requires accurate patient positioning (technique sensitive)
- Difficult to image both jaws when patient has severe maxillomandibular discrepancy (class III malocclusion specifically, patient cannot move mandible back to be in line with the maxilla on the bite block)
Because panoramic radiographs have low resolution areas, this does not allow for:
detections of small carious lesions or early periodontal disease
Where do we see overlap in panoramic radiographs?
premolar area
Describe the magnification of panoramic images:
magnification is unequal across the image so making linear measurements is unreliable
Describe when a panoramic may not be indicated due to patient occlusion:
Class III malocclusion (patient cannot move mandible back to be in line with maxillary on bite block)
(would need to do a separate pano of maxilla and mandible)
Label the parts of the panoramic machine:
Blue: Light/Laser localizer (sagittal plane-center)
Orange: Light/Laser localizer (horizontal planevfrankfort)
Yellow: Bite block and handles for patient
Red: X-ray source and tube inside of it
Green: Head supports/guides
Purple: Receptor/sensor of pano machine
What type of panoramic machine does UMKC use?
Orthophos XG Sirona
Label the following parts of the panoramic machine:
B: Light/laser localizer- horizontal plane- frankfurt
C: Light/laser localizer- sagittal plane- center
F: Head supports/guides
I: Receptor/sensor
J: X-ray source & tube inside of it
K: Bite block
M: Bite block handles
When the x-ray source is on the right, the ____ side is being image
left
When x-ray source is on the left side, the ___ side is being imaged
right
Describe the imaging technique of a panoramic machine:
continuous movement imaging
Discuss the collimator location on a panoramic machine:
there is a collimator at both the exit of the source and the entrance of the receptor
In a panoramic machine, there are multiple ____ that are constantly moving:
continuous centers of rotation
Where does the x-ray source start in a panoramic radiograph? Where does it end?
starts on the right and ends on the left
Where does the x-ray source never go in a panoramic radiograph?
NEVER goes in front of the patient
When the source is in the back of the patient, where is the receptor?
In the front of the patient
Where does the head of the patient located at the start of the panoramic radiograph?
between receptor and source
The first image that is created is the patients ____ because the x-ray source starts on the ____
left; right
What is closer to the receptor will be:
imaged
In this image, the x-ray source is on the ____ and the receptor is on the ____.
At what point in time does this occur?
What is being imaged?
right; left
beginning of panoramic
imaging left
In this image, the x-ray source is:
At what point in time does this occur?
Where is the receptor located?
behind the patient
mid-panoramic radiographic
receptor in front
In this image, the x-ray source is:
At what point in time does this occur?
Where is the receptor located?
What is being imaged?
on left side of patient
end of panoramic radiograph
receptor on the right
right side
Instead of ____ receptors, we now use ____ receptors
PSP/Film; CCD
What differs between the CCD receptors we currently use, versus the PSP/Film receptors previously used?
CCD: sensors will be sent to computer and then repeated, exposed on same spot of receptor
PSP/Film: continuously exposed different areas on one receptor
What type of receptor is being described?
Exposure of the same area over and over again and do not need a “new” portion of the receptor
CCD receptor
What type of receptor is being described?
Receptors continuously expose different areas on one receptor
PSP/Film
Area of focus:
focal trough
Describe the focal trough:
an area of focus; a 3D curbed zone in which structures are reasonably and well defined.
Where is the focal trough narrower?
anterior
Is where both dental arches must be positioned to achieve the sharpest images:
Focal trough
Structures positioned in the ___ will result in the clearest images:
center of focal trough
What may occur if objects are placed further from the focal through?
progressively less clear:
- blurred
- magnified
- reduced in size
- distored
How can you ensure sharpness in a panoramic radiograph?
By having both mandibular and maxillary anteriors placed in bite block groove
What does having both mandibular and maxillary anteriors placed in bite block groove ensure in panoramic radiograph?
Ensures sharpness of image
Beams are angulated approximately 4 degrees to avoid projection of:
thick occipital bone
To avoid the occipital bone, beams are angulated approximately:
4 degrees
_____ between the objects in a panoramic radiograph may not be accurate
spacial relationships