Panoramic Imaging Principles Flashcards by Annabella Moody

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. dentomaxillofacial trauma
7. developmental disturbances or syndromes

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List the advantages of panoramic radiography: (6)

relatively low radiation dose (compared to FMX)
broad coverage of facial bones & teeth
easier technique
can be used in patients with trismus or in patients who cannot tolerate intraoral radiographs (more comfortable & faster)
quick & convenient radiographic technique
useful visual aid in patient education

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List the disadvantages of panoramic radiography: (6)

lower resolution areas (not able to detect small carious lesions of early periodontal disease)
overlap in premolar area
magnification across image is equal making linear measurements unreliable
image is superimposition of real, double & 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 maxilla on bite block)

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Because panoramic radiographs have lower resolution areas this does not allow for:

detection of small carious lesions or early periodontal disease

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Where do we see overlap in panoramic radiographs?

premolar areas

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Describe the magnification of panoramic images:

magnification across image is unequal so linear measurements are unreliable

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Describe when a panoramic radiograph may not be indicated due to patient occlusion:

Class III malocclusion (patient cannot move mandible back to align with maxilla on bite stick)

(would need to obtain separate panoramic images of maxilla and mandible)

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Label the following parts of the panoramic machine:

Blue: light/laser localizer (sagittal plane-center)
Orange: light/laser localizer (horizontal plane- frankfurt)
Yellow: bite block & handles for patient
Red: X-ray source & the tube inside it
Green: Head support/guides
Purple: receptor/sensor of pano machine

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What type of panoramic machine does UMKC use?

Orthophos XG Sirona

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Label the following parts of the panoramic machine: b

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- handles for patient

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When the X-ray source is on the right side, the ____ side is being imaged

left

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When the X-ray source is on the left side, the ____ is being imaged

right

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Describe the imaging technique of a panoramic machine:

Continuous movement imaging

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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

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In a panoramic machine, there are multiple ______ that are are constantly moving

Centers of rotation

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Where does the X-ray source start in a panoramic radiograph?

Where does the X-ray source end in a panoramic radiograph?

Starts on the right

Ends on the left

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Where does the X-ray source NEVER go in a panoramic radiograph?

NEVER goes in front of patient

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When the source is in the back of the patient, where is the receptor?

In the front of the patient

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Where is the head of the patient located at the start of the panoramic radiograph?

Between the receptor and the source

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The first image that is created is the patients ______ because the X-ray source starts on the ____

left; right

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What is closer to the receptor is what will be:

imaged

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In this image, the X-ray source is on the _____ and the receptor is on the ____

At what point in time does this occur during a panoramic radiograph?

What is being imaged?

right; left

Beginning of panoramic radiograph

Imaging left

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In this image, the X-ray source is:

At what point in time does this occur during a panoramic radiograph?

Where is the receptor located?

behind the patient

Mid panoramic radiograph

receptor is in front

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In this image, the X-ray source is:

At what point in time does this occur during a panoramic radiograph?

Where is the receptor located?

What is being imaged?

left side of patient

End of panoramic radiograph

receptor is on the right side

imaging right

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Instead of ______ receptors we now use _____ receptors

PSP/Film; CCD

What differs between the CCD receptors we use now vs. the PSP/Film receptors previously used:

CCD: Sensors will be sent to computer and then repeated, exposed on same spot of receptor PSP/Film: receptors continuously expose 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 receptor

Area of focus:

Focal trough

Describe the focal trough:

An area of focus; a 3D curved zone in which structures are reasonable and well defined

Where is the focal trough narrower?

Anteriorly

Is where both dental arches must be positioned to achieve the sharpest images:

Focal trough

Structures placed in the ______ will result in the clearest image

center of focal trough

What may occur if objects are placed further from the focal trough?

Progressively less clear: -blurred -magnified -reduced in size -distorted

How can you ensure sharpness in a panoramic radiograph?

By having both mandibular and maxillary anteriors placed in blot 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 may not be accurate in a panoramic radiograph

spatial relationships

Give an example of a spatial relationship that may not be accurate, and therefore can be misrepresented on panoramic radiographs:

distance between root apex & mandibular canal

Objects closer to the receptor will appear:

Narrowed & projected lower on the image

Objects closer to the source will appear:

widened & projected higher up on the image

Objects closer to the ____ will appear narrowed & projected lower on the image Objects closer to the ____ will appear widened & higher up

receptor; source

Buccal objects will be projected:

lower

Lingual objects will be projected:

higher

____ objects will be projected lower, while ____ objected will be projected higher

buccal; lingual

Horizontal magnification is determined by:

the position of the object within the focal trough

_____ magnification is determined by the position of the object within the focal trough

horizontal

Magnitude of distortion depends on:

distance of the object from the center of the focal trough

Lingual to the focal trough = closer to the _____= appears _____

source; wider

_____to the focal trough = closer to the source= objects appear wider

lingual

Why do objects lingual to the focal trough/ closer to the source appear wider?

The beam passes more slowly through it than the speed at which the receptor moved

Buccal to the focal trough = closer to the _____ = appears _____

receptor; narrower

_____ to the focal trough = closer to the receptor=objects appear narrower

buccal

Why do objects buccal to the focal trough/ closer to the receptor appear narrower?

The beam passes at a rate faster than the receptor movement

The green dot would appear _____ The red dot would appear ____ Explain

narrower; wider Green dot is buccal to the focal tough (closer to the receptor) Red dot is lingual to the focal trough (closer to the source)

Image distortions are only in:

the horizontal plane

The image distortions are only in the horizontal plane but varies between:

anterior & posterior regions of the mandible

____ region = horizontal magnification increases as object moves away from center of focal trough

anterior region

What type of horizontal distortions are more severe?

anterior region

____ region= less degree of magnification

posterior region

What type of horizontal distortions are less severe?

posterior region

The magnitude of horizontal distortion varies between:

anterior & posterior regions of the jaw

In the anterior region, horizontal magnification increases markedly as the:

object moves AWAY from the center of the focal trough

There is a less degree of magnification in the:

posterior region

Two identical objects located in the anterior & posterior regions may have:

different horizontal magnifications

Horizontal measurements made on panoramic radiographs are:

unreliable

Every anatomical structure positioned between the center of rotation & the receptor results in:

real images

Where do real images occur?

every anatomical structure positioned between the center of rotation & the receptor

This image is describing:

Real images

What is depicted by the arrow & dot in this image?

Rotation center

Created by objects located between the x-ray source & the center of rotation:

Ghost images

Describe how ghost images appear{

1. on the opposite side 2. at a higher level 3. blurred & magnified

Anatomical structures that cast a ghost image include: (7)

1. inferior border of mandible 2. angle of mandible 3. ramus of mandible 4. hyoid bone 5. cervical spine 6. jewelry 7. palate

Ghost image are created by objects located:

between the X-ray source & center of rotation

1. inferior border of mandible 2. angle of mandible 3. ramus of mandible 4. hyoid bone 5. cervical spine 6. jewelry 7. palate These all have the potential to result in:

ghost images

What does the orange circle represent?

Object that would create a ghost image

What does the orange circle represent?

Object that would create a real image

List the characteristics of ghost shadows: (4)

1. appears on the opposite side 2. positioned higher than real structure 3. more blurred than real structure 4. vertical component is highly magnified

These are all characteristics of:

ghost shadows

What type of image would this earring create?

ghost image

What can be seen in this panoramic image?

ghost image of inferior border of the mandible and hard palate

What can be seen in this panoramic image?

Ghost image of inferior border of the mandible

What can be seen in this panoramic image?

Ghost image of nose ring

What can be seen in this panoramic image?

Ghost image of necklace

What can be seen in this panoramic image?

Ghost image of cervical spine

Objects that lie posterior to the center of rotation and that are intercepted twice by the X-ray beam result in:

double images

Double images occur due to:

objects that lie posterior to the center of rotation & are intercepted twice by the X-ray beam

What structures may result in double images? (3)

1. hyoid bone 2. epiglottis 3. cervical spine

They hyoid bone, epiglottis & cervical spine, all result in double images, all of which:

cast images on both the right & left side of the image

All double images are:

real images

What is depicted by the orange structure in this image?

Object causing double image

What can be seen in this panoramic image?

Double image of the hyoid bone

What can be seen in this panoramic image?

Double image of the cervical spine

What can be seen in this panoramic image?

Double image of the epiglottis

List the steps of positioning for a panoramic X-ray: (9)

1. remove jewelry, glasses & dentures 2. place lead apron 3. Bite in biteblock groove 4. stand patient upright 5. align the center laser line 6. align the Frankfurt horizontal plane 7. close side guides 8. Have Pt close their lips, swallow & keep tongue on palate & hold still 9. expose the radiograph

What image shows the correct body position?

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