牙科放射線學 (2) oral digital image artifacts 口腔數位影像失誤 陳玉昆副教授 :...
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牙科放射線學 (2)
Oral Digital Image Artifacts
口腔數位影像失誤
陳玉昆副教授 : 高雄醫學大學 口腔病理科 07-3121101~2755 [email protected]
• Identify and classify oral digital image artifacts
• Know how to eliminate oral digital image artifacts
學 習 目 標
1. Eric Whaites: Essentials of dental radiography & radiology 3rd edition, Chapter 17
2. White & Pharoah: Oral radiology: principle & interpretation 5th edition, Chapter 22
References
3. Kaohsiung Medical University, Oral Pathology Department
4. Parks ET, et al. J Contemp Dent Pract 2002;4:23-39
Photostimulable phosphor storage plate (PSP) system
Digital Image Artifacts
Ref. 3
PSP sensor plates
Side towardsX-ray tube
Equivalent to the ‘dot’ on conventional radiographic film
Ref. 3
PSP sensor plate
Sealed with disposablebarrier envelope
Ref. 3
A black box used to protectthe sensor plate fromroom light
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Teeth of both jaws ground down until smooth & a plastic tube was inserted into the smaller jaw
Snap-A-Ray holding device
Modified Snap-A-Ray holding device Ref. 3
Conventionalocclusal film
Ref. 3
Double-sided tape
Double-sided tape
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Protection of digital occlusal image plate (1)
Ref. 3
Protection of digital occlusal image plate (2)
(A) 將傳統咬合 X光片內的黑紙及鉛片拿下
(B) 按照黑紙及鉛片之相同大小裁剪兩片泡棉
(C) 將此兩片泡棉分黏貼在黑紙及鉛片外層
Ref. 3
Protection of digital occlusal image plate (3)
(A) 將黑紙泡棉外側用立可白點上一白點
(B) 使用時將數位咬合 PSP感應片夾入黑紙及鉛片中間，感應片藍色感光面朝向黑紙面且將’ a’ 點對準黑紙泡棉外側用立可白點上的白點
(C) 為防止交叉感染，將裝好的咬合 PSP感應片放入夾鏈袋內。
Ref. 3
Normal & defective PSP sensor plates
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Protection of PSP sensor plate (1)
5 min later
PSP sensor plate( 易受損面 ) 沖洗後新的傳統根尖片：呈透明、可透光
放置於 PSP sensor plate易受損面上： X光可透過，可保護易受損面
置於 PSP sensor plate封套內PSP sensor plate封套
Ref. 3
Protection of PSP sensor plate (2)
傳統根尖片片套 PSP 感應片片套
Operator Errors
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Correct orientation of sensor plate within the cassette
Ref. 3
A
C The sensor plate was incorrectly placed upside down within the cassette Ref. 3
AC
The surface of the sensor plate exposed to the X-ray was incorrectly inclined during the scanning process
Ref. 3
Repeated X-ray exposure ofthe same intraoral sensor plate
Retaken a corrected image
Ref. 3
Image obtained was too bright due to delayed sensor plate scanning
Ref. 3
Bending of the intraoral sensorplate within the mouth
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Scanning Machine Errors
Refs. 3, 4
Image obtained was too brightdespite scanning with optimalconditions and procedures
Ref. 3
Image obtained was too brightdespite scanning with optimalconditions and procedures
Ref. 3
A B
Image obtained was too brightdespite scanning with optimalconditions and procedures
Correct image obtained afterrescanning with anotherscanner
Ref. 3
Uneven brightness of an extraoral image after scanning
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An additional horizontal white line was noted after scanning
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B
Reduction in imagesize after scanning
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After the scanning of two different intraoral sensor platesin two different slots of the scanning machine, the two resulting images was overlapped
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Only half of the intraoral imagewas displayed after scanning
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Sensor Errors
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A B
Defective image resulting from sensor platedamaged by scratches or bite mark
Ref. 3
Defective image resultingfrom sensor platedamaged by bite mark
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Defective image resulting from partial peeling of the crystalline halide coating of the intraoral sensor plate
Ref. 3
Defective image resulting from sensor plate damagedby teeth of the jaws of a Snap-A-Ray
Ref. 3
Miscellaneous Errors
Ref. 4
Normal orientationof cassette withincassette holder
Ref. 3
Opposite side of the cassettewas wrongly placed facing theX-ray tube
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Opposite side of the cassette was wrongly placed facing the X-ray tube
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Normal orientationof cassette withincassette holder
The cassette was incorrectly placed upside downwithin the cassette holder of the X-ray machine
The cassette was incorrectly placed upside downwithin the cassette holder of the X-ray machine
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The cassette was incorrectly placed upside downwithin the cassette holder of the X-ray machine
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The cassette was incorrectly placed upside downwithin the cassette holder of the X-ray machine
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The cassette was incorrectly placed upside downwithin the cassette holder of the X-ray machine
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The cassette was incorrectly placed upside downwithin the cassette holder of the X-ray machine &then scanned upside down
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The cassette was incorrectly placed upside downwithin the cassette holder of the X-ray machine &then scanned upside down
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Digora cassette 放反
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A further example of image obtained was too bright due to delayed sensor plate scanning (N.B. overlap of two sensor plates)
Ref. 3
數位底片在洗片前二張重疊 1
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數位底片在洗片前三張重疊的最底下一張
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Further example of defective image
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Further example of defective image
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Further example of defective image
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Further example of defective image
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Further example of defective image
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Further example of defective image
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Further example of defective image
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Further example of defective image
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Further example of defective image
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Further example of defective image
1. Important ways of decreasing the radiation dose are to determine whether there is an explicit clinicalindication for each exposure and to make sure thateach exposure is taken under adequate conditions,thereby avoiding the formation of image artifacts& minimizing the necessity for repeated exposures.
2. Understanding the reasons for the formation of image artifacts, particularly for the newly-emerging dental digital radiography technique, is of high clinical importance.
Summaries