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 ~2755
Identify and classify oral digital image artifacts Know how to eliminate oral digital image artifacts 學 習 目 標學 習 目 標 1. Eric Whaites: Essentials of dental radiography & radiology 3rd edition, Chapter 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 towards X-ray tube Equivalent to the ‘dot’ on conventional radiographic film Ref. 3
PSP sensor plate Sealed with disposable barrier envelope Ref. 3
A black box used to protect the sensor plate from room light Ref. 3
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
Conventional occlusal film Ref. 3
Double-sided tape Double-sided tape Ref. 3 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
Ref. 3 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 Ref. 4
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
A C The surface of the sensor plate exposed to the X-ray was incorrectly inclined during the scanning process Ref. 3
Repeated X-ray exposure of the 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 sensor plate within the mouth Ref. 3
Scanning Machine Errors Refs. 3, 4
Image obtained was too bright despite scanning with optimal conditions and procedures Ref. 3
Image obtained was too bright despite scanning with optimal conditions and procedures Ref. 3
A B Image obtained was too bright despite scanning with optimal conditions and procedures Correct image obtained after rescanning with another scanner Ref. 3
Uneven brightness of an extraoral image after scanning Ref. 3
An additional horizontal white line was noted after scanning Ref. 3
B Reduction in image size after scanning Ref. 3
After the scanning of two different intraoral sensor plates in two different slots of the scanning machine, the two resulting images was overlapped Ref. 3
Only half of the intraoral image was displayed after scanning Ref. 3
Sensor Errors Ref. 3
A B Defective image resulting from sensor plate damaged by scratches or bite mark Ref. 3
Defective image resulting from sensor plate damaged by bite mark Ref. 3
Defective image resulting from partial peeling of the crystalline halide coating of the intraoral sensor plate Ref. 3
Defective image resulting from sensor plate damaged by teeth of the jaws of a Snap-A-Ray Ref. 3
Miscellaneous Errors Ref. 4
Normal orientation of cassette within cassette holder Ref. 3
Opposite side of the cassette was wrongly placed facing the X-ray tube Ref. 3
Opposite side of the cassette was wrongly placed facing the X-ray tube Ref. 3
Normal orientation of cassette within cassette holder
The cassette was incorrectly placed upside down within the cassette holder of the X-ray machine
The cassette was incorrectly placed upside down within the cassette holder of the X-ray machine Ref. 3
The cassette was incorrectly placed upside down within the cassette holder of the X-ray machine Ref. 3
The cassette was incorrectly placed upside down within the cassette holder of the X-ray machine Ref. 3
The cassette was incorrectly placed upside down within the cassette holder of the X-ray machine Ref. 3
The cassette was incorrectly placed upside down within the cassette holder of the X-ray machine & then scanned upside down Ref. 3
The cassette was incorrectly placed upside down within the cassette holder of the X-ray machine & then scanned upside down Ref. 3
Digora cassette 放反 Ref. 3
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 Ref. 3
數位底片在洗片前三張重疊的最底下一張 Ref. 3
Further example of defective image
Ref. 3 Further example of defective image
Ref. 3 Further example of defective image
Ref. 3 Further example of defective image
Ref. 3 Further example of defective image
Ref. 3 Further example of defective image
Ref. 3 Further example of defective image
Ref. 3 Further example of defective image
Ref. 3 Further example of defective image
Ref. 3 Further example of defective image
1. Important ways of decreasing the radiation dose are to determine whether there is an explicit clinical indication for each exposure and to make sure that each 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