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牙科放射線學 (1) 陳玉昆副教授 : 高雄醫學大學 口腔病理科 07-3121101~2755 Panoramic Radiography (1) (2) 環口放射線攝影術 ( 1) (2)

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Presentation on theme: "牙科放射線學 (1) 陳玉昆副教授 : 高雄醫學大學 口腔病理科 07-3121101~2755 Panoramic Radiography (1) (2) 環口放射線攝影術 ( 1) (2)"— Presentation transcript:

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

2 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 學 習 目 標學 習 目 標

3 1. Eric Whaites: Essentials of dental radiography & radiology 3rd edition, Chapter 14-15, p White & Pharoah: Oral radiology: principle & interpretation, 5th edition, Chapter 10, p 參考資料 (1) 3. Kaugars GE et al. Panoramic ghosts. Oral Surg Oral Med Oral Pathol 1987;63: Mason RA. Sydney Blackman 1898 – 1971 A pioneer of panoramic radiography. Dent Maxillofac Radiol 1998;27: 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: Brown RS et al. Synthetic hair braid extension artifacts in panoramic radiographs. JADA 1998;129: Aydin U. Tuberculous lymph node calcification detected on routine panoramic radiography: a case report. Dent Maxillofac Radiol 2003;32:252-4

4 8. Reuter I et al. Triple images on panoramic radiographs Dent Maxillofac Radiol 1999;28: Kaohsiung Medical University Oral Pathology 10. McDavid W et al. Real, double, and ghost images in rotational panoramic radiography. Dentomaxillofac Radiol 1983;12: Scheifele C. Hair artefacts in the head and neck region. Dentomaxillofac Radiol 2003;32:255-7 參考資料 (2) 12. Farman AF et al. The role of the dentist in detection of carotid atherosclerosis. S Afr Dent J 2001;56: Eric Whaites: Essentials of dental radiography & radiology 4th edition, 2007, p 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, Sansare K et al. Oral tuberculosis: unusual radiographic findings. Dentomaxillofac Radiol 2011;40:251-6

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

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

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

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

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

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

15 Shifting Rotation Centers Ref. 1 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 Shifting centers

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

17 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 3D focal trough Focal Trough Film Refs. 1, 2, 3 X-ray source Rotation center Film In focus 的區域 (focal trough)

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

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

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

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

22 Split movement pattern Continuous movement pattern Real image zone Midline object 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 Double image Ref. 10 Real (Primary) Image

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

24 Ghost 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 Ghost (Secondary) Image

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

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

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

28 Film Rotation center Position 1 Position 2 X-ray source G R G R G R X-ray source 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 Blurring of Ghost Image Ref. 10

29 Distance from the x-ray source (mm) x-ray source Rotation center Central plane of the layer Film Ghost image Real image Vertical magnification Horizontal magnification Horizontal magnification Vertical magnification = Horizontal magnification Magnification factor Magnification of Panorex 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 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 Ref. 13 Cervical vertebrae Ramus Palate Summaries of Ghost Image

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

33 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 Ghost Images as an Aid to Localize Soft Tissue Calcifications

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

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

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

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

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

39 Triple Image Ref. 8 Retained foreign body (shrapnel) 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 Real image

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

41 Positions of Objects Showing I, II & III Images Ref. 8 Center of rotation LeftRight 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 I B II III II I A II IB III R R R L L L LR 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

42 Positions of Object is Related to the Formation of Single, Double and Triple Images 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) abc 1 x 2 x 3 x Ref. 8 (a)X-ray beam moves from its starting point to the anterior rotation center creates a single (1x) & an initial double (2x) image (b)Moves around the anterior center creates single (1x) & double images (2x) of objects in the central region (c)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)

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 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 (A)(B) (C)(D)

45 Effect of Carotid Atherosclerosis *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 Ref. 14 Blood clot Fatty deposits Internal carotid artery Common carotid artery Cerebral arteries Blood supply from the heart

46 Diagrammatic Illustration of Panorex of Cartoid Atherosclerosis (1) Ref. 14 A C1 C2 C3 C4 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

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

48 Ref. 14 Some Examples (1) B

49 Ref. 14 Some Examples (2) C

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

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

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

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

54 Refs. 12, 14 Differentiate with Structures in Vicinity 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 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)

55 Refs. 12, 14 Differentiate with Structures in Vicinity 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 Phleboliths in patients with sclerosing hemangioma The calcifications are not carotid calcifications & should be differentiate from carotid calcification Ref. 12 Differentiate with Venous Calcification

57 Ref. 9 More Example for Phlebolith

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

59 Organ Systems Frequently Affected in Extrapulmonary Tuberculosis Ref. 7 Site Lymph nodes (13 - a 85%) Pleura (9-77%) Genitourinary system ( a %) Central nervous system (1 - b 36%) Bones and joints ( a %) Gastrointestinal system ( a %) Disseminated tuberculosis (7, 12%) Pericardium (1 - 6%) Peritoneum (4%) a In surgical specimens b Including spinal/vertebral tuberculosis

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

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

62 Ref. 7 Differential Diagnosis of Projected Radiopacities 1.Lymph node calcification 2.Sialolith 3.Radiopaque lesions of the bone (when superimposed to mandible) 4.Superimposed myositis ossificans 5.Idiopathic calcification 6.Ghost images 7.Foreign bodies 8.Carotid atheromas 9.Calcified stylohyoid ligament complex 10.Tonsillithiasis 11.Phleboliths

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

69 Hair Artifact Ref. 11

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

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

72 Metal Artifact Ref. 9

73 Position Error Ref. 1 Positioning errorFilm 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 Refs. 1, 9 Positioning errorFilm fault 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 Position Error

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

76 謝 謝


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