1. Panoramic Radiography (1) (2)
牙科放射線學(1)
Panoramic Radiography (1) (2)
環口放射線攝影術 (1) (2)
陳玉昆副教授: 高雄醫學大學 口腔病理科
~2755

2. 學 習 目 標 Historical Aspect Theory of Tomographic Movement
Concept of Rotation Center &
Focal Trough
Kinds of Image on Panorex
Role of Dentist to Detect Carotid
Atherosclerosis on Panorex
Normal Structures on Panorex
Common & Position Errors on
Panorex

3. 參考資料 (1)
1. Eric Whaites: Essentials of dental radiography & radiology 3rd edition,
Chapter 14-15, p
2. White & Pharoah: Oral radiology: principle & interpretation, 5th edition,
Chapter 10, p
3. Kaugars GE et al. Panoramic ghosts. Oral Surg Oral Med Oral Pathol
1987;63:103-8
4. Mason RA. Sydney Blackman 1898 – 1971 A pioneer of panoramic
radiography. Dent Maxillofac Radiol 1998;27:371-5
5. Monsour PA. et al. Panoramic ghost images as an aid in the localization
of soft tissue calcifications. Oral Surg Oral Med Oral Pathol
1990;69:748-56
6. Brown RS et al. Synthetic hair braid extension artifacts in panoramic
radiographs. JADA 1998;129:601-4
7. Aydin U. Tuberculous lymph node calcification detected on routine
panoramic radiography: a case report. Dent Maxillofac Radiol
2003;32:252-4

4. 參考資料 (2)
8. Reuter I et al. Triple images on panoramic radiographs Dent Maxillofac
Radiol 1999;28:316-9
9. Kaohsiung Medical University Oral Pathology
10. McDavid W et al. Real, double, and ghost images in rotational panoramic
radiography. Dentomaxillofac Radiol 1983;12:122-8
11. Scheifele C. Hair artefacts in the head and neck region. Dentomaxillofac
Radiol 2003;32:255-7
12. Farman AF et al. The role of the dentist in detection of carotid
atherosclerosis. S Afr Dent J 2001;56:549-53
13. Eric Whaites: Essentials of dental radiography & radiology 4th edition,
2007, p
14. João César Guimarães Henriques et al. Panoramic radiography in the
diagnosis of carotid artery atheromas and the associated risk factors.
The Open Dentistry Journal, 2011, 5, 79-83
15. Sansare K et al. Oral tuberculosis: unusual radiographic findings.
Dentomaxillofac Radiol 2011;40:251-6

5. A pioneer of panoramic radiography
Historical Aspect
Sydney Blackman
A pioneer of panoramic radiography
Ref. 4

6. Obtained With The Rotograph
Examples of Panorex
Obtained With The Rotograph
Multiple unerupted teeth in an 8-yr old child
Developing dentition in a 13-yr old child
Ref. 4

7. Types of Tomographic Movement
Theory of Tomographic
Movement
Types of Tomographic Movement
1. Linear: Thin x-ray beam
Broad x-ray beam
2. Circular
3. Ellipical
4. Spiral
5. Hypocycloidal

8. Linear: thin x-ray beam
Direction of
movement of
the film
x-ray tubehead
Points A-F all appear on different parts
of the film and are blurred out
Point O, centre of rotation, appears in the same place
on the film throughout the exposure and is sharply defined
Finish
Start
Finish
Start
Linear: broad x-ray beam
X-ray tube-
head
Film
Multiple center of rotations
Zone within the focal plane
(section of the patient):
sharply defined on film
Start
Finish
Start
Finish
Ref. 1

9. Width of Focal Plane : Amount of movement (angle of swing)
Large movement
Thin focal
plane
Small movement
Thick focal
plane
Ref. 1

10. Linear Tomographic Principle –
Section in Focus
Film plane and direction of film travel
Direction of X-ray tube travel
Object plane
Rotation
center
Blurred
Section in focus
Ref. 10

11. Different Types of Tomography
Circular / Elliptical
Hypocycloidal
【數學】圓內旋輪線，內擺線
Spiral
Ref. 1

12. Rotation Center Film moves Start inside the cassette carrier
Finish
Tubehead orbits
behind the head
Cassette carrier
orbits in front of
the face
Film moves
inside the
cassette carrier
X-ray source
Cassette
carrier
Beam
Film inside
cassette
carrier self orbit
Refs. 1, 3

13. Various Types of Rotation Center
2 stationary
3 stationary
Continually
moving
3 stationary &
Continuous mode
Split mode
Ref. 1

14. Shifting Rotation Centers
X-ray
source
Shifting
center
Shifting Rotation Centers
Film
Ref. 2

15. Shifting Rotation Centers
Cassette carrier
orbits around the
front of the face
The film
also starts
to move
Start
Shifting centers
The entire film
has been
exposed
Finish
Ref. 1

16. Shifting Rotation Centers
Cassette carrier
orbits around the
front of the face
The film
also starts
to move
Start
Shifting centers R L
Continuous mode
Split mode
The entire film
has been
exposed
Finish
Shifting centers
Ref. 1

17. X-ray source Rotation center Film In focus的區域 (focal trough)
3D focal trough
x = Height of x-ray beam (collimation)
f = Height of film
d = Distance between focal trough
& film
Upward angulation
Final image is slightly
magnified
Collimation
Film
3D focal trough
X-ray source Rotation center Film
In focus的區域 (focal trough)
Refs. 1, 2, 3

18. asymmetrically to the machine
Different Shapes of Focal Trough
In front of
focal trough
Behind
Patient is placed
asymmetrically to the machine
Impaction can
be seen
Impaction
cannot
Different shapes of focal trough
Vertical wall of focal trough in incisor region
Class I
Class II
Class III
Shaded area outside focal trough is out of
focus and will be blurred
Refs. 1, 3

19. Example of Panorex Machine
X-ray
source
cassette
Cassette
carrier
Orbit
behind
patient
before
Cassette
with film
inside
carrier
Refs. 10, catalogue of manufacturer

20. Example of Panorex Machine
Control panel
X-ray
source
F-H plane
Anterior
Bite block
3D focal trough
Refs. 10, catalogue of manufacturer

21. Kinds of Image Real (Primary) image: Real (primary) image
Double real (lateral) image
Ghost (secondary) image
Triple image
Object
X-ray
source
Real
image
Rotation
center
Film
Real (Primary)
image:
When the object is located
between the rotation
center and the film
(within the focal trough
with minimal unsharpness
& distortion)
Ref. 10

22. Real (Primary) Image Midline object Double Continuous movement pattern
Real image zone
Real image zone
Always blurred because
corresponding to a region
between rotation center &
central plane of layer
May not be blurred since
corresponding to a region
include the sharply depicted
plane in anterior region
Midline
object
Double
image
Continuous movement pattern
Split movement pattern
Ref. 10

23. Double (Real) Lateral Image
Double image of nasal gastric tube
Refs. 9, 10

24. Ghost (Secondary) Image
X-ray
source
Object
Rotation
center
Film
Ghost (Secondary)
image:
When the object is located
between the rotation
center & the x-ray source
(outside the focal trough
with unsharpness and
distortion; the closer the
rotation center, the more
distortion of the image)
Ref. 10

25. Ghost Envelope Split movement pattern Ghost envelope Composite 3 D
Panorex
3 D
ghost envelope
Split movement pattern
3 D
ghost
envelope
Continuous movement pattern
Ghost envelope
Composite
Orthopantomograph-5
Panelipse
3 D
ghost envelope
Refs. 3, 5, 10

26. Ghost Image (1) Ghost image X-ray source Rotation center Curved x-ray
film
Half
dry skull
Real image R
Ghost image
Refs. 1, 10

27. Ghost Image (2) Bilateral double real + Central ghost = Triple images
Cervical
spine
Bilateral double real
Central ghost
Bilateral double real + Central ghost
= Triple images
Midline
chain
Refs. 9, 10

28. Blurring of Ghost Image
Film
Rotation center
Position 1
Position 2
X-ray
source G R
R: In the real image zone moves in
the same direction as the film
G: In the ghost image zone moves in
the opposite direction as the film
Image is extremely blurred
Ref. 10

29. Magnification of Panorex
Distance from the x-ray source (mm)
x-ray source
Rotation
center
Central plane
of the layer
Film
100
200
300
400
500 1 2 3 4 5
Ghost
image
Real
Vertical
magnification
Horizontal
Vertical magnification
= Horizontal magnification
Magnification factor
Refs. 3, 10

30. Summaries of Ghost Image
1. The object is dense enough to block
radiation
2. It is located outside focal trough
3. It is located inside ghost envelope
Ref. 3
1. It will always be distorted, especially the
horizontal component.
2. In most cases, it will be seen radiographically at a higher location than the primary object.
3. It may not been seen on a clinical radiograph if superimposed over areas of dense anatomy.
4. It may appear even if the primary object is not seen on the radiograph.
5. It will always have some degree of radiopacity.
Characteristics of a Ghost Image:
6. Pronounced horizontal blurring indicates
that the primary object was at or close to center of rotation.
7. It is reversed when compared with the primary image.
8. It can be caused by physical objects such as earrings, a napkin chain, a necklace, a zipper on a pullover sweater, amalgam restorations or crowns, and radon or radium implants.
9. It can be caused by anatomic structures, such as the body & ramus of the mandible or cervical vertebrae.
10. It can be caused by parts of panoramic machine such as the chin rest or the letters R & L on the head positioner.
11. It can be pathologic (e.g. a sialolith or an impacted third molar).

31. Summaries of Ghost Image
Cervical vertebrae
Ramus
Palate
Ref. 13

32. Summaries of Ghost Image
Ramus
(real image)
(ghost image) R L
Ref. 13

33. Ghost Images as an Aid to Localize Soft Tissue Calcifications
Basic Principle:
Location and appearance
of ghost images shown on the
panoramic radiograph can provide
information of the soft tissue
calcifications or predict the
locations of the soft tissue
calcifications

34. Object is along the median plane
Location of lead sphere
Ghost image
Occlusal view
Lateral view
Central ghost g
Object is along the median plane
No ghost image
No ghost image
No ghost image
Ref. 5

35. Object is buccal or lingual to mandibular body
Location of lead sphere
Ghost image appearance
Occlusal view
Lateral view
No ghost image
No ghost image
No ghost image
Ref. 5

36. Object is inferior to ramus
Location of lead sphere
Ghost image
Occlusal view
Lateral view
No ghost image
No ghost image
Ghost image
Ref. 5

37. Object is posterior to condyle
Location of lead sphere
Ghost image
Lateral view
Occlusal view
Object is posterior to condyle
Ref. 5

38. Object is lateral or medial of ramus
Ghost image
Location of lead sphere
Occlusal view
Lateral view
Double primary
image
Ref. 5

39. Triple Image Retained foreign body (shrapnel) Triple image
Ghost image
Real image
Position of primary object did not change; creation of a triple image is due to slight differences in patient positioning
Triple image
Real image
Ghost image
2 Ghost images
Ref. 8

40. Positions of Object Showing
Triple Image
a: X-ray beam
b (yellow arrows): direction of tube movement
c: path of rotation center
d: center of image layer
Position 1
Position 2
Triple image
Triple image
Position 3
Position 4
Position 5
Position 6
Triple image
Triple image
Ref. 8

41. Positions of Objects Showing
I, II & III Images
Center of rotation
Left
Right
Diagram showing the areas where the test object is portrayed once (IA, IB), twice (II) and thrice (III). The solid white line indicates the path of rotation center & the dotted line the center of image layers
I A II IB
III R L
Diagram showing the location of the 1, 2 & 3 images & the extent of distortion of the test object in relation to regions IA, B, II & III. The path of rotation center is shown as a solid white line. Note how triple images are generated in region III
I A
III II II
I B
Ref. 8

42. Triple image: a b c One real & two ghost images (diamond- shaped area
Positions of Object is Related to the Formation
of Single, Double and Triple Images a b c
1 x
2 x
3 x
Triple image:
One real & two ghost
images (diamond-
shaped area
immediately
distal to path of
rotation of center)
Two lateral real and
one central ghost
images
(cervical spine)
X-ray beam moves from its starting point to the anterior rotation center creates a single (1x) & an initial double (2x) image
Moves around the anterior center creates single (1x) & double images (2x) of objects in the central region
Moves from the anterior rotation center to the end of tube movement completes the formation of lateral images (2x) & also portrays the central region for a third time (3x)
Ref. 8

43. Role of Dentist to Detect Carotid Atherosclerosis
Atheroma：Calcified plaques especially composed of lipids and fibrous tissue deposited on the walls of blood vessels  trigger atherosclerosis.
Atherosclerosis：A chronic inflammatory disease of an immunological nature, characterized by thickening and loss of elasticity of the arterial walls, associated with the presence of atheromas.

44. Development of Atherosclerosis
(B)
(C)
(D)
Development of atherosclerosis:
(A) Cross sectional cut of the artery when it was still whole
(B) Initial injury of the endothelium
(C) The atheromatous plaque formed
(D) A thrombus associated with the plaque, completely obstructing the hollow passage of the vessel
Ref. 14

45. Effect of Carotid Atherosclerosis
Cerebral
arteries
*When affect the carotids (supply the brain)  strokes
*When affect the coronary (supply the heart)  myocardial infarction
*Result in the death of thousands of people all over the world
Blood clot
Internal
carotid
artery
Fatty
deposits
Common
carotid
artery
Blood supply from the heart
Ref. 14

46. Diagrammatic Illustration of Panorex of Cartoid Atherosclerosis (1)
Why is PANOREX?
1. Low radiation doses, low cost and has technical simplicity
2. Normally deposited along the ascendant trajectory of the common carotid artery that
bifurcates into internal and external carotid arteries  comprised within the area of
coverage of panoramic radiography
Ref. 14

47. Diagrammatic Illustration of Panorex of Cartoid Atherosclerosis (2)
Carotid atherosclerosis
Atherosclerotic
calcifies
that can be
seen on
panorex
angle of
mandible
external
carotid
artery
hyoid
internal
atheroma
common
bifurcation
Ref. 12

48. Some Examples (1) B
Ref. 14

49. Some Examples (2) C
Ref. 14

50. Some Examples (3) Calcified carotid atheroma (arrow)
Calcified atheromas
of carotid artery
bifurcation (arrows)
Ref. 12

51. More Example (1) Bilateral carotid atherosclerosis
Upper arrow on the right shows a
calcified triticeous cartilage
Calcified atheromatous
plaque (arrow)
Ref. 12

52. More Example (2)
A carotid plaque (arrows) visible in the left neck inferior & posterior to the
angle of the mandible
Ref. 7

53. More Example (3)
Small carotid plaque (arrows) visible in the right & left neck, inferior &
posterior to the angle of the mandible
Ref. 7

54. Differentiate with Structures in Vicinity
Care needs to be taken to differentiate between calcified atheroma & other structures in vicinity that can also calcify (thyroid cartilage, thyroid gland, triticeous cartilage, epiglottis)
Triticeous (triticeal) cartilage
Homogeneous RO when calcified
Regular oval shapes
~2-4mm wide, 7-9mm long
Superimposed on the airspace
of pharynx
- Close to superior portion of C4
Refs. 12, 14

55. Differentiate with Structures in Vicinity
Refs. 12, 14
The best way to differentiate:
PA radiograph taken by means of Modified Towne technique
Atheromas dispose laterally to the vertebrae, whereas the triticeal cartilages (a more medial localization) will not be observed (superimposed on the spinal column)

56. The calcifications are not carotid calcifications &
Differentiate with Venous Calcification
Phleboliths in patients
with sclerosing hemangioma
The calcifications are not
carotid calcifications &
should be differentiate
from carotid calcification
Ref. 12

57. More Example for Phlebolith
Ref. 9

58. Calcified Lymph Node Shown on Panorex
Carotid
atheroma
Ghost image
Calcified
lymph node
Ref. 7

59. Organ Systems Frequently Affected in Extrapulmonary Tuberculosis
Site
Lymph nodes (13 - a85%)
Pleura (9-77%)
Genitourinary system (a2 - 74%)
Central nervous system (1 - b36%)
Bones and joints (a2 - 17%)
Gastrointestinal system (a9 - 16%)
Disseminated tuberculosis (7, 12%)
Pericardium (1 - 6%)
Peritoneum (4%)
aIn surgical specimens
bIncluding spinal/vertebral tuberculosis
Ref. 7

60. Extrapulmonary Tuberculosis -
Jaw Bones & TMJ
Resorption of condylar process
Ref. 15

61. Extrapulmonary Tuberculosis -
Jaw Bones & TMJ
Resorption of angle of mandible
Diffuse area of rarefaction in the mandible near the extraction socket
Ref. 15

62. Differential Diagnosis of Projected Radiopacities
Lymph node calcification
Sialolith
Radiopaque lesions of the bone (when superimposed to mandible)
Superimposed myositis ossificans
Idiopathic calcification
Ghost images
Foreign bodies
Carotid atheromas
Calcified stylohyoid ligament complex
Tonsillithiasis
Phleboliths
Ref. 7

63. Normal Structures (1)
Ref. 2

64. Normal Structures (2)
Zygmatic arch
Hyoid
bone
Ref. 2

65. Normal Structures (3)
Dorsum of tongue
Soft palate
Earlobe
Ref. 2

66. Various Landmarks on Panorex (1)
Ref. 2

67. Various Landmarks on Panorex (2)
Ref. 2

68. Common Errors Denture Earring Orthodontic appliance Earring Lead apron
Necklace
Metal plates
Ref. 1

69. Hair Artifact
Ref. 11

70. Hair Braid Artifact A: synthetic hair braid extension artifacts
B: Nose ring artifact
Ref. 6

71. Hair Braid Artifact
A: synthetic hair braid extension artifacts
Ref. 6

72. Metal Artifact
Ref. 9

73. Position Error Ref. 1 Positioning error Film fault
Patient too far from the film
Patient too close to the film
Patient positioned
asymmetrically (head
turned to the right or left)
Patient‘ s chin positioned
too high or too low
Anterior teeth magnified
in width & out of focus
Anterior teeth narrowed
& out of focus
Posterior teeth enlarged on
one side & reduced on
the other
Distortion in the shape of
the mandible & the
anterior teeth out of focus

74. Position Error Positioning error Film fault Refs. 1, 9
Patient positioned
asymmetrically (head
turned to the right or left
Patient still wearing earrings,
jewellery, dentures or
orthodontic appliances
Failure to instruct the patient
to keep still throughout the
cycle
Posterior teeth enlarged on
one side and reduced on
the other
Artefactual shadow(s) of
the offending object
Vertical or horizontal
distortion of the part of the
image being produced at
the time of the movement
Refs. 1, 9

75. Knowing: Historical Aspect Theory of Tomographic Movement
Concept of Rotation Center
& Focal Trough
Kinds of Image on Panorex
Role of Dentist to Detect Carotid
Atherosclerosis on Panorex
Normal Structures on Panorex
Common & Position Errors on
Panorex

76. Your constructive comments are appreciated
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