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Panoramic x-ray Islam Kassem
Level 6
ikassem@dr.com
2D panoramic imaging
ikassem@dr.com
High Quality Images, Effortlessly
•
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Concepts of Panoramic Radiography Introduction
Dr.walaa
ikassem@dr.com
Introduction to Panoramic
Radiography
• Commonplace in dental practice
• Considered essential in radiographic
diagnosis
• 30% of dental units sold are
panoramic
ikassem@dr.com
Introduction to Panoramic
Radiography
• “Panorama” means unobstructed
view of a region in any direction
• Panoramic radiograph show greater
coverage than periapical and
bitewing radiographs
ikassem@dr.com
Introduction to Panoramic
Radiography
• New technique
• Introduced in 1959
• Employs scanography (slit beam) &
curved surface rotational
tomography
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Client Dose from Panoramic
Radiography
• 10 times less radiation than a complete intraoral survey using long, round PID & E+ film
• 4 time less radiation than a bitewing survey using long, round PID and E+ film
ikassem@dr.com
Indications for Panoramic
• Pathology-cysts, tumors
• Trauma-fractures
• Growth & development
• Client management
• Edentulous
• Localization: anatomy, objects, implant placement
• Carotid artery condition
ikassem@dr.com
Advantages of Panoramic
Radiography
• Field size
• Quality control
• Simplicity
• Time & rapidity of the procedure
• Client cooperation
• Dose
• Minimal infection control
• Gross anatomy & pathology visible
ikassem@dr.com
Disadvantages of Panoramic
Radiography
• Image quality
• Focal trough limitations
• Equipment costs
• Overuse
ikassem@dr.com
Disadvantages of Panoramic
Radiography
• Image quality
– Magnification
– Distortion
– Poor definition compared to intraoral
– Overlap
– Superimposition & ghost images
ikassem@dr.com
Disadvantages of Panoramic
Radiography
• Poor image quality due to
– Tomographic process
– Increased object-film distance
– Use of intensifying screens
– Faster film with larger crystals
ikassem@dr.com
Disadvantages of Panoramic
Radiography
• Focal Trough (Image Layer)
– Areas outside are not visible
– Size & shape limits imagery to those
structures which “fit” into the image
layer
– Size & shape not adjustable so not all
client’s arches image equally well
ikassem@dr.com
Disadvantages of Panoramic
Radiography
• Distortion
– Vertical & horizontal distortion with
variations causes uneven magnification
ikassem@dr.com
Disadvantages of Panoramic
Radiography
• Superimposition & Ghost Images
– All objects in the field of the beam, even
those outside of the image layer are
projected onto the film but most are not
seen.
– Objects with the greatest density are
projected in two places on the film
• Intended (useable image)
• Ghost image (reversed, higher, blurred)
ikassem@dr.com
Disadvantages of Panoramic
Radiography
• Superimposition & Other Imaging
Quirks
– Ghost images may hide pathosis
– Soft tissue shadows may mimic
pathosis
ikassem@dr.com
ikassem@dr.com
Focal Trough
• An imaginary, three-dimensional curved area that is horseshoe shaped.
• This is a very important concept because many technique errors are caused by improper positioning of the patient’s jaws within the focal trough.
• When the jaws are positioned within this area, the radiograph will be clear.
• When the jaws are positioned outside of this area, the images on the radiograph will appear blurred or indistinct.
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ikassem@dr.com
Components of the Panoramic Unit
• Panoramic x-ray tubehead
• Head positioner
• Exposure controls
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ikassem@dr.com
The Head Positioner
• Each panoramic unit has a head positioner used to align the patient’s teeth as accurately as possible.
• Each head positioner consists of a chin rest, notched bite-block, forehead rest, and lateral head supports or guides.
• Each panoramic unit is different, and the operator must follow the manufacturer’s instructions on how to position the patient in the focal trough.
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ikassem@dr.com
ikassem@dr.com
Positioning of the Teeth
• Posterior to focal trough • If the patient’s anterior teeth are not positioned in
the groove on the bite-block and are either too far back on the bite-block or posterior to the focal trough, the anterior teeth appear “fat” and out of focus on the radiograph.
• Anterior to focal trough • If the patient’s anterior teeth are not positioned in
the groove on the bite-block and are either too far forward or anterior to the focal trough, the teeth will appear “skinny” and out of focus.
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ikassem@dr.com
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ikassem@dr.com
Positioning of the Spine
If the patient’s spine is not straight, the cervical spine will appear as a radiopaque artifact in the center of the film and obscure diagnostic information.
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ikassem@dr.com
ikassem@dr.com
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ikassem@dr.com
ikassem@dr.com
ikassem@dr.com
ikassem@dr.com
ikassem@dr.com
ikassem@dr.com
ikassem@dr.com
Common Errors
• Patient preparation errors • Ghost images: A ghost image looks like the real object
except that it appears on the opposite side of the film. • Lead apron artifact: If the lead apron is placed too
high, or if a lead apron with a thyroid collar is used, a cone-shaped radiopaque artifact results.
• Patient seating errors • Chin too high • Chin too low
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ikassem@dr.com
ikassem@dr.com
Thank you
ikassem@dr.com
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