A detailed seminar on panoramic radiography discussing basics, physics, uses and faults.

4. Panoramic radiography (orthopantomography, PAN) is the most frequently
prescribed screening examination in dentistry .
This technique has several advantages, particularly a relatively low cost, a low
radiation dose, and the possibility of obtaining a comprehensive overview of dental
arches, maxillary and mandibular bones, as well as of relevant anatomic structures
to be preserved during surgery, such as inferior alveolar nerves and maxillary
sinuses.
Moreover, PAN has been found to have a high number of line pairs per millimeter
(lp/mm), ranging from 1.6 to 3.0 lp/mm.
Interestingly, according to the literature, PAN has a better number of line pairs than
cone beam computed tomography,which is reported to range between 0.6 and 2.8
lp/mm in experimental settings and decreases down to above 1 lp/mm in clinical
settings.

7. PAN is a zonography performed by means of a simultaneous rotation of an X-ray beam
generator and a detector system—curved rotational thick-layer tomography—that are
both mounted on a rotating gantry and positioned on either side of patient.
The X-ray tube rotates clockwise around the patient’s head from right to left, passing
behind the shoulders and making an arc of about 270. The final image is the result
ofreconstructions of individual image sections of the maxillofacial area.
The one to-one correspondence between each point of dental arches crossed by a
collimated beam and its projection on the detector is the basis of PAN image formation.

18. 1. Stationary rotation centers( split image)
2. Single rotation center(the rotagraph machine)
3. Double rotation center(panorex machine)
4. Triple rotation center(orthopantomography,panorama,panora)
5. Multiple rotation centers
6. Moving rotation center(eclipso-pantomography)

19. Illustration showing rotation centers.

20. • The center of rotation changes as the film and tube head rotate around
the patient, the rotational change allows the image layer to conform to
the elliptical shape of the dental arches.
• The location and number of rotational centers influences the size and
shape of the focal trough.
• All the machines employ a moving rotational center that traces a path of
shape of an eclipse, so theis system is called as “Eclipso-
pantomography”.

21. The Soredex Company (Helsinki, Finland) was the first to
produce units (Cranex DC) with constant potential
generators, starting in 1978.

22. The Zonarc (Instrumentarium/Palomex) was the
first unit with several electronically programmed
image layer tracks. The patient was examined in
the supine position
Hallikainen D. History of panoramic radiography. Acta
radiologica. 1996 Jan 1;37(3):441-5.

29. A three-dimensional display of the focal trough demonstrating the X, Y, and Z axes.
The X-axis represents the horizontal transverse axis around which the model was
rotated in a counter-clockwise direction (radiograph T4), viewed from the right of the
patient. The Y-axis represents the vertical reference axis in the midline and the Z-axis
represents the antero-posterior (sagittal) axis around which the model was canted to
the left and right (radiographs T2 and T3). The posterior part of the focal trough is
larger in all dimensions (taken from Langland et al., 1989).

32. AUTOPAN 098 EC
BELMONT ; JAPAN
STANDING
BITE BLOCK
60-90 KVp
6mA
13.5 sec
Flexible cassette
6X12 inches

33. ROTOGRAPH 230
FIAD; ITALY
STANDING
BITE BLOCK CHIN REST CUP
65-85KVp
10mA
15 sec
Curved rigid
5X12 inch

34. GX-PAN
GENDEX;UNITED STATES
STANDING
BITE BLOCK
65-100KVp
4mA
15 Sec
Flexible
5X12 inches

37. PANELIPSE II
GENDEX
UNITED STATES
SEATED
BITE BLOCK
65-100 KVp
4mA
20 sec
FLEXIBLE
5x12 inches

38. PANOREX II
KEYSTONE X-RAY;UNITED STATES
SEATED
SPLIT-CHIN REST,BITE BLOCK
51-90KVp
5mA
Split-18.4 sec,continuous-20 sec
FLEXIBLE
5x12 Inches

39. VERSAVIEW
J.MORITA
JAPAN
STANDING
BITE BLOCK
70-90KVp
0-10 mA
15 sec
FLEXIBLE
5X12 inches or 6X12 inches

40. OP 10
PALOMEX
FINLAND
STANDING BITE BLOCK
57-90KVp
5-12mA
15sec
RIGID CURVED
5X12 inches

41. PM 2002 CC
PLANMECA OY
FINLAND
STANDING BITE BLOCK
60-80KVp
4-12mA
4-20 sec
RIGID FLAT
6x12 inches

42. SANKO
SANKO MANUFACTURING CO.
JAPAN
SEATED/STANDING
BITE BLOCK,LIGHT,OR FLIP UP
SCALE
70-90KVp
8mA
15sec
FLEXIBLE
6x12 inches

43. ORALIX PAN DC
SOREDEX; FINLAND
STANDING
BITE BLOCK/CHINUP
63-81KVp
6/10mA
16sec
RIGID FLAT
6x12 inches

44. PANOURA 10
YOSHIDA; JAPAN
SEATED /STANDING
BITE BLOCK/CHIN REST CUP
70-90KVp
6mA
12sec
FLEXIBLE
6x12 inches

52. IMAGE RECEPTORS IN DIGITAL OPG
• CCD(charged couple devices) or photostimulable phosphor plates (PSP)
These transmits an electric signal to the controlling computer ,which displays the
image on the computer screen.
• Both the digital modalities allow the user to perform post processing
modificationson the image using linear contrast and density
adjustments,black/white reversals,magnifications,edge enhancements,and color
rendering.
• Software used-DICOM(DIGITAL IMAGING AND COMMUNICATION IN
MEDICINE)

53. • In response to the increased use of digital images in radiology the American College
of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA)
formed a joint committee in 1983 to create a standard format for storing and
transmitting medical images.
• The committee published the original ACR-NEMA standard in 1985.
• This has subsequently been revised and in 1993 the standard was renamed DICOM.
• More recent improvements in DICOM (Version 3.0) have permitted transfer of
medical images in a multi-vendor environment, and importantly, have facilitated the
development of PACS and digital interfacing with medical information systems.

54.  Lossy compression file types Joint photographic experts group format
(JPEG) This image type allows the user to specify how much
compression is applied and hence how much of the original data are lost.
Lossless compression file types Portable network graphics format
(PNG) The PNG image format has several good features: Variable
degree of transparency; image brightness control (gamma correction)
and two-dimensional interlacing (initially every other line of the image
data is displayed) for rapid image viewing
 Tagged image file format (TIFF) With TIFF files either lossless or lossy data
compression can be specified. Lossless compression is generally performed
using the Lempel-Ziv-Welch (LZW) algorithm written by Abraham Lempel
and Jacob Ziv in 1977 and 1978 and improved by Terry Welch in 1984, hence
the name LZW.

55.  Graphic interchange format (GIF) This image format was first
produced in 1987 and uses the LZW lossless compression
algorithm. The compression of GIF images is less efficient than
PNG files (by about 5–25%) and this file type lacks the wide-
ranging features of the newer PNG.
 Joint photographic experts group 2000 format (JPEG 2000)
This is another example of an image file using lossless
compression.
 JPEG 2000 images allow certain parts of the image to be
defined as a region of interest (ROI), which can then be
displayed before other parts of the image, or be losslessly
compressed, whilst other less critical parts of the image
undergo lossy compression. Like PNG, JPEG 2000 allows
metadata to be embedded in the image file.

56. Image degradation resulting from excessive
lossy data compression:
(a) High-resolution JPEG image (144 kb)
of an axial T2-weighted MRI image of the
brain showing a right-sided acoustic neuroma
(white arrow);
(b) Moderate compression of the same JPEG
image (64 kb) showing no significant image
degradation;
(c) highly compressed JPEG (32 kb)
demonstrating marked image degradation.

73. BONY LANDMARKS OF THE MAXILLA AND SURROUNDING
STRUCTURES

86. Concept of the real,ghost
and double images

87. The diagram shows zones 1A and 1B
(formation of one image),
zone 2 (formation of two images), and
zone 3 (formation of
three images).

88. Ghost images: This is a
radiopaque artifact seen on
a panoramic film that is produced
when a
radiodense object is penetrated
twice by the Xray
beam

89. Ghost images of metal plates

90. Ghost image of contra ramus
Ghost images of earrings

91. Ghost image of spine

92. Lead apron artifact appears as a large cone
shaped radiopacity obscuring the mandible

94. shows a single real image of the metal sphere.

95. shows two images: one real ipsilateral image and one
distorted contralateral ghost image

100. The chin and the occlusal plane are rotated upward,
resulting in the overlapping of the images of the
teeth and an opaque shadow (the hard palate) obscuring
the roots of the maxillary teeth

101. An exaggerated smile seen on a panoramic film
when the patient’s chin is tipped down

102. The anterior teeth appear narrow and blurred on a
panoramic film when the patient is positioned too far
forward on the bite block

104. The anterior teeth appear widened and blurred on a
panoramic film when the patient is positioned too far back
on the bite block

105. The patient’s posterior teeth and ramus appear to be
magnified on the panoramic film when the head is not
centered

106. If the patient is not standing erect, superimposition of the
cervical spine may be seen on the center of the
panoramic film

107. If the tongue is not placed on the roof of the mouth, a
radiolucent shadow will be superimposed over the apices
of the maxillary teeth

115. • True positive, false negative, and false positive represented by the following
colors: green, red, and blue, respectively. A) Three-grade classification of
the amount of corrections on the colored images. B) Examples of AI
underestimations (false negative) and overestimations (false positive). C)
Examples of underestimations and overestimations only at the crown, the

117. Comparison between AI prediction and the
ground truth on two different panoramic
radiographs