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 07-3121101~2755 yukkwa@kmu.edu.tw

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

參考資料 (1) 1. Eric Whaites: Essentials of dental radiography & radiology 3rd edition, Chapter 14-15, p. 153-76. 2. White & Pharoah: Oral radiology: principle & interpretation, 5th edition, Chapter 10, p. 191-209 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

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. 198-9. 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

A pioneer of panoramic radiography Historical Aspect Sydney Blackman 1898-1971 A pioneer of panoramic radiography Ref. 4

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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).

Summaries of Ghost Image Cervical vertebrae Ramus Palate Ref. 13

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

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

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

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

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

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

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

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

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

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

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

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.

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

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

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

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

Some Examples (1) B Ref. 14

Some Examples (2) C Ref. 14

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

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

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

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

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

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)

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

More Example for Phlebolith Ref. 9

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

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

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

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

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

Normal Structures (1) Ref. 2

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

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

Various Landmarks on Panorex (1) Ref. 2

Various Landmarks on Panorex (2) Ref. 2

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

Hair Artifact Ref. 11

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

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

Metal Artifact Ref. 9

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

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

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

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