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1、牙科放射線學(1)Still waters run deep.流静水深流静水深,人静心深人静心深 Where there is life,there is hope。有生命必有希望。有生命必有希望Historical AspectTheory of Tomographic MovementConcept of Rotation Center&Focal TroughKinds of Image on PanorexRole of Dentist to Detect Carotid Atherosclerosis on PanorexNormal Structures on PanorexCom
2、mon&Position Errors on Panorex學 習 目 標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.191-209參考資料(1)3.Kaugars GE et al.Panoramic ghosts.Oral Surg Oral Med Oral Pathol 1987;63:
3、103-84.Mason RA.Sydney Blackman 1898 1971 A pioneer of panoramic radiography.Dent Maxillofac Radiol 1998;27:371-55.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 e
4、xtension artifacts in panoramic radiographs.JADA 1998;129:601-47.Aydin U.Tuberculous lymph node calcification detected on routine panoramic radiography:a case report.Dent Maxillofac Radiol 2003;32:252-48.Reuter I et al.Triple images on panoramic radiographs Dent Maxillofac Radiol 1999;28:316-9 9.Kao
5、hsiung Medical University Oral Pathology10.McDavid W et al.Real,double,and ghost images in rotational panoramic radiography.Dentomaxillofac Radiol 1983;12:122-811.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 dent
6、ist in detection of carotid atherosclerosis.S Afr Dent J 2001;56:549-5313.Eric Whaites:Essentials of dental radiography&radiology 4th edition,2007,p.198-9.14.Joo Csar Guimares Henriques et al.Panoramic radiography in the diagnosis of carotid artery atheromas and the associated risk factors.The Open
7、Dentistry Journal,2011,5,79-8315.Sansare K et al.Oral tuberculosis:unusual radiographic findings.Dentomaxillofac Radiol 2011;40:251-6 Historical AspectSydney Blackman 1898-1971A pioneer of panoramic radiographyRef.4Examples of Panorex Obtained With The RotographMultiple unerupted teeth in an 8-yr ol
8、d childDeveloping dentition in a 13-yr old childRef.4Theory of Tomographic Movement Types of Tomographic Movement1.Linear:Thin x-ray beam Broad x-ray beam2.Circular3.Ellipical4.Spiral5.HypocycloidalLinear:thin x-ray beamDirection of movement of the filmDirection of movement of x-ray tubeheadPoints A
9、-F all appear on different parts of the film and are blurred outPoint O,centre of rotation,appears in the same placeon the film throughout the exposure and is sharply definedLinear:broad x-ray beamX-ray tube-headFilmMultiple center of rotationsZone within the focal plane(section of the patient):shar
10、ply defined on filmStartStartStartStartFinishFinishFinishFinishRef.1Width of Focal Plane:Amount of movement (angle of swing)Large movementThin focal planeSmall movementThick focal planeRef.1 Film plane and direction of film travelDirection of X-ray tube travelObject planeRotation centerBlurredSectio
11、n in focusBlurredLinear Tomographic Principle Section in FocusRef.10HypocycloidalCircular/EllipticalSpiralDifferent Types of TomographyRef.1【數學】圓內旋輪線，內擺線 StartFinishTubehead orbitsbehind the headTubehead orbitsbehind the headCassette carrierorbits in front ofthe faceCassette carrierorbits in front o
12、fthe faceFilm movesinside thecassette carrier Rotation CenterRefs.1,3X-ray sourceCassettecarrierBeamFilm insidecassettecarrier self orbitVarious Types of Rotation Center2 stationary3 stationaryContinuallymoving3 stationary&movingContinuous modeContinuous modeContinuous modeSplit modeRef.1X-raysource
13、Shifting centerX-raysourceShifting centerShifting Rotation CentersFilmFilmRef.2Shifting Rotation CentersRef.1Cassette carrierorbits around the front of the faceThe filmalso startsto moveStartShifting centersThe entire filmhas been exposedFinishShifting centersContinuous modeSplit modeThe entire film
14、has been exposedFinishShifting centersCassette carrierorbits around the front of the faceThe filmalso startsto moveStartShifting centersRLRef.1Shifting Rotation Centers3D focal troughx=Height of x-ray beam(collimation)f =Height of filmd=Distance between focal trough&filmUpward angulationFinal image
15、is slightlymagnifiedCollimation3D focal troughFocal TroughFilmRefs.1,2,3In front of focal troughBehindfocal troughPatient is placedasymmetrically to the machineImpaction canbe seenImpactioncannotbe seen Vertical wall of focal trough in incisor regionClass IClass IIClass IIIShaded area outside focal
16、trough is out of focus and will be blurredDifferent shapes of focal troughRefs.1,3Different Shapes of Focal TroughX-ray sourcecassetteCassettecarrierOrbitOrbitbehindpatientOrbitbeforepatientCassettewith filminsideCassettecarrierRefs.10,catalogue of manufacturer Example of Panorex MachineControl pane
17、lX-raysource3D focal troughF-H planeAnteriorBite blockRefs.10,catalogue of manufacturer Example of Panorex MachineKinds of Image Real (primary)imageDouble real(lateral)imageGhost(secondary)imageTriple image Real(Primary)image:When the object is located between the rotation center and the film(within
18、 the focal troughwith minimal unsharpness&distortion)ObjectX-raysourceRealimageRotationcenterFilmRef.10Split movement patternContinuous movement patternReal image zoneReal image zoneMidline objectAlways blurred becausecorresponding to a region between rotation center¢ral plane of layerMay not be
19、 blurred sincecorresponding to a region include the sharply depictedplane in anterior regionDouble imageRef.10Real(Primary)ImageDouble image of nasal gastric tube Refs.9,10Double(Real)Lateral Image GhostimageX-raysourceObjectRotationcenterFilm Ghost(Secondary)image:When the object is located between
20、 the rotation center&the x-ray source(outside the focal troughwith unsharpness anddistortion;the closer therotation center,the moredistortion of the image)Ref.10Ghost(Secondary)ImageContinuous movement patternGhost envelopeCompositeSplit movement patternGhost envelopeCompositeOrthopantomograph-5Pane
21、lipse3 D ghost envelopePanorex3 D ghost envelopeSplit movement pattern3 D ghost envelopeRefs.3,5,10Ghost Envelope Half dry skullReal imageRGhost imageCurved x-ray filmGhostimageX-raysourceRotationcenterRefs.1,10Ghost Image(1)MidlinechainRefs.9,10Ghost Image(2)Cervical spineCervical spineBilateral do
22、uble realCentral ghostBilateral double real+Central ghost=Triple imagesFilmFilmRotation centerPosition 1Position 2X-raysourceGRGRGRX-raysourceR:In the real image zone moves in the same direction as the filmG:In the ghost image zone moves in the opposite direction as the filmImage is extremely blurre
23、dBlurring of Ghost ImageRef.10Distance from the x-ray source(mm)x-ray sourceRotation centerCentral planeof the layerFilm0100200300400500102345GhostimageRealimageVerticalmagnificationHorizontalmagnificationHorizontalmagnificationVertical magnification=Horizontal magnificationMagnification factorMagni
24、fication of PanorexRefs.3,10Summaries of Ghost Image1.The object is dense enough to block radiation2.It is located outside focal trough3.It is located inside ghost envelopeRef.31.It will always be distorted,especially the horizontal component.2.In most cases,it will be seen radiographically at a hig
25、her 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 hor
26、izontal 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
27、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)
28、.Ref.13CervicalvertebraeRamusPalateSummaries of Ghost ImageRef.13Ramus(real image)Ramus(ghost image)RLSummaries of Ghost Image Basic Principle:Location and appearance of ghost images shown on thepanoramic radiograph can provideinformation of the soft tissuecalcifications or predict thelocations of t
29、he soft tissuecalcificationsGhost Images as an Aid to Localize Soft Tissue CalcificationsLocation of lead sphere Ghost imageOcclusal viewLateral viewCentral ghostg Object is along the median planeRef.5No ghost imageNo ghost imageNo ghost imageObject is buccal or lingual to mandibular body Ghost imag
30、e appearanceOcclusal view Location of lead sphereLateral viewRef.5No ghost imageNo ghost imageNo ghost imageLocation of lead sphere Ghost imageOcclusal viewLateral view Object is inferior to ramusGhost imageRef.5No ghost imageNo ghost image Location of lead sphere Ghost imageLateral viewOcclusal vie
31、w Object is posterior to condyleGhost imageGhost imageRef.5 Object is lateral or medial of ramus Ghost image Location of lead sphereOcclusal viewLateral viewGhost imageGhost imageGhost imageDouble primaryimageRef.5Triple ImageRef.8Retained foreign body(shrapnel)Ghost imageReal imagePosition of prima
32、ry object did not change;creation of a triple image is due to slight differences in patient positioningTriple imageReal imageGhost image2 Ghost imagesReal imagePositions of Object ShowingTriple ImagePosition 1Position 2Position 3Position 4Position 5Position 6Triple imageTriple imageTriple imagea:X-r
33、ay beamb(yellow arrows):direction of tube movementc:path of rotation centerd:center of image layerRef.8Triple imagePositions of Objects Showing I,II&III ImagesRef.8Center of rotationLeftRightDiagram showing the areas where the test object is portrayed once(IA,IB),twice(II)and thrice(III).The solid w
34、hite line indicates the path of rotation center&the dotted line the center of image layersI AI BII III III AIIIBIIIRRRLLLLRDiagram 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 w
35、hite line.Note how triple images are generated in region IIIPositions of Object is Related to the Formationof Single,Double and Triple ImagesTriple image:One real&two ghostimages(diamond-shaped area immediatelydistal to path ofrotation of center)Two lateral real andone central ghostimages(cervical s
36、pine)abc1 x2 x3 xRef.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 e
37、nd of tube movement completes the formation of lateral images(2x)&also portrays the central region for a third time(3x)Role of Dentist to Detect Carotid AtherosclerosisAtheroma：Calcified plaques especially composed of lipids and fibrous tissue deposited on the walls of blood vessels trigger atherosc
38、lerosis.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 AtherosclerosisDevelopment of atherosclerosis:(A)Cross sectional cut of the artery when
39、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)Effect of Carotid Atherosclerosis*When affect the carotids(supply the brain)strokes*When affect th
40、e coronary(supply the heart)myocardial infarction*Result in the death of thousands of people all over the world Ref.14Blood clotFattydepositsInternalcarotidarteryCommoncarotidarteryCerebralarteriesBlood supply from the heartDiagrammatic Illustration of Panorexof Cartoid Atherosclerosis(1)Ref.14AC1C1
41、C2C2C3C3C4C4Why is PANOREX?1.Low radiation doses,low cost and has technical simplicity2.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 radiographyCarotid ath
42、erosclerosisAtheroscleroticcalcifiesthat can be seen on panorexangle ofmandibleexternalcarotidarteryhyoidinternalcarotidarteryatheromacommoncarotidarterybifurcationRef.12Diagrammatic Illustration of Panorexof Cartoid Atherosclerosis(2)Ref.14Some Examples(1)BRef.14Some Examples(2)CSome Examples(3)Ref
43、.12 Calcified carotid atheroma(arrow)Calcified atheromas of carotid artery bifurcation(arrows)More Example(1)Ref.12 Bilateral carotid atherosclerosis Upper arrow on the right shows a calcified triticeous cartilage Calcified atheromatous plaque(arrow)More Example(2)Ref.7 A carotid plaque(arrows)visib
44、le in the left neck inferior&posterior to the angle of the mandibleMore Example(3)Ref.7 Small carotid plaque(arrows)visible in the right&left neck,inferior&posterior to the angle of the mandibleRefs.12,14Differentiate with Structures in VicinityTriticeous(triticeal)cartilageHomogeneous RO when calci
45、fied-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
46、)Refs.12,14Differentiate with Structures in VicinityThe best way to differentiate:PA radiograph taken by means of Modified Towne techniqueAtheromas dispose laterally to the vertebrae,whereas the triticeal cartilages(a more medial localization)will not be observed(superimposed on the spinal column)Ph
47、leboliths in patientswith sclerosing hemangiomaThe calcifications are notcarotid calcifications&should be differentiatefrom carotid calcificationRef.12Differentiate with Venous CalcificationRef.9More Example for PhlebolithCalcified Lymph NodeShown on PanorexRef.7RLCarotid atheromaGhost imageCalcifie
48、dlymph nodeOrgan Systems Frequently Affected in Extrapulmonary TuberculosisRef.7Site 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 su
49、rgical specimensbIncluding spinal/vertebral tuberculosisExtrapulmonary Tuberculosis-Jaw Bones&TMJRef.15Resorption of condylar processExtrapulmonary Tuberculosis-Jaw Bones&TMJRef.15Resorption of angle of mandibleDiffuse area of rarefaction in the mandible near the extraction socketRef.7Differential D
50、iagnosis ofProjected Radiopacities1.Lymph node calcification2.Sialolith3.Radiopaque lesions of the bone(when superimposed to mandible)4.Superimposed myositis ossificans5.Idiopathic calcification6.Ghost images7.Foreign bodies8.Carotid atheromas9.Calcified stylohyoid ligament complex10.Tonsillithiasis