Concepts of Panoramic
Radiography
Introduction
DHY 202 Clinical Radiology I
Dental Hygiene Department
William Rainey Harper College
Introduction to Panoramic
Radiography
• Commonplace in dental practice
• Considered essential in radiographic
diagnosis
• 30% of dental units sold are
panoramic
Introduction to Panoramic
Radiography
• “Panorama” means unobstructed
view of a region in any direction
• Panoramic radiograph show greater
coverage than periapical and
bitewing radiographs
Introduction to Panoramic
Radiography
• New technique
• Introduced in 1959
• Employs scanography (slit beam) &
curved surface rotational
tomography
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
Indications for Panoramic
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Pathology-cysts, tumors
Trauma-fractures
Growth & development
Client management
Edentulous
Localization: anatomy, objects,
implant placement
• Carotid artery condition
Advantages of Panoramic
Radiography
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Field size
Quality control
Simplicity
Time & rapidity of the procedure
Client cooperation
Dose
Minimal infection control
Gross anatomy & pathology visible
Disadvantages of
Panoramic Radiography
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Image quality
Focal trough limitations
Equipment costs
Overuse
Disadvantages of
Panoramic Radiography
• Image quality
– Magnification
– Distortion
– Poor definition compared to intraoral
– Overlap
– Superimposition & ghost images
Disadvantages of
Panoramic Radiography
• Poor image quality due to
– Tomographic process
– Increased object-film distance
– Use of intensifying screens
– Faster film with larger crystals
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
Disadvantages of
Panoramic Radiography
• Distortion
– Vertical & horizontal distortion with
variations causes uneven magnification
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)
Frommer 2001
Disadvantages of
Panoramic Radiography
• Superimposition & Other Imaging
Quirks
– Ghost images may hide pathosis
– Soft tissue shadows may mimic
pathosis