牙科放射線學(1)教案.ppt
《牙科放射線學(1)教案.ppt》由会员分享,可在线阅读,更多相关《牙科放射線學(1)教案.ppt(76页珍藏版)》请在得力文库 - 分享文档赚钱的网站上搜索。
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
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 牙科 放射 教案
限制150内