• Title/Summary/Keyword: Digital imaging

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Digital imaging of film-based cephalograms using a digital camera (디지털 카메라를 이용한 필름 두부방사선사진의 디지털 이미지 전환)

  • Wang, Sung-Jin;Kim, Kyung-Ho;Choy, Kwang-Chul
    • The korean journal of orthodontics
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    • v.34 no.5 s.106
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    • pp.448-457
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    • 2004

  • As computer Programs for cephalometric analysis were developed in diagnosis & treatment planning, digital imaging of film-based cephalograms came to be needed. When a digital camera is used, a problem encountered the image distortion produced according to the focal length, which causes errors in indentifying landmarks. In addition, changes in the image size and compression ratio will inevitably produce a low quality image, causing errors in identifying landmarks. Hence. we have found the focal length producing the least image distortion when digital imaging the film-based cephalograms and the minimal digital camera setting which helps to identify the correct landmarks using the COOLPIX4500 digital camera (Nikon, Japan). The results were as follows The image distortion was minimized at a focal length of 16.4mm (79.4mm when converted into a 35mm film camera) when digital imaging the film-based cephalograms. When wide imaging, with a focal length of under IS.4mm, barrel distortion was found and when tole imaging. with a focal length of over 15.4mm pincushion distortion was found. The minimal digital camera setting was $2272{\times}1704$ pixel at normal (1/8) compression from which we can identify the correct landmarks at the same level as tracing the film-based cephalograms manually. As a result. when digital imaging the film-based cephalograms, using a COOLPIX4500 digital camera (Nikon, Japan), the focal length should be 16.4mm the pixel image size over $2272{\times}1704$, and the compression ratio over normal (1/8).

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Comparative Efficacy of Four Imaging Instruments for Breast Cancer Screening

  • Mehnati, Parinaz;Tirtash, Maede Jafari
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.15
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    • pp.6177-6186
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    • 2015

  • Sensitivity and specificity are the two most important indicators in selection of medical imaging devices for cancer screening. Breast images taken by conventional or digital mammography, ultrasound, MRI and optical mammography were collected from 2,143,852 patients. They were then studied and compared for sensitivity and specificity results. Optical mammography had the highest sensitivity (p<0.001 and p<0.006) except with MRI. Digital mammography had the highest specificity for breast cancer imaging. A comparison of specificity between digital mammography and optical mammography was significant (p<0.021). If two or more breast diagnostic imaging tests are requested the overall sensitivity and specificity will increase. In this literature review study patients at high-risk of breast cancer were studied beside normal or sensitive women. The image modality performance of each breast test was compared for each.

  • https://doi.org/10.7314/APJCP.2015.16.15.6177 인용 PDF KSCI

Imaging Characteristics of Digital Chest Radiography with an Amorphus Silicon Flat Panel Detectors (비정질 평판형 측정기를 이용한 디지털 방사선 영상의 특징)

  • Jeong, Hoi-Woun;Kim, Jung-Min;Jeong, Man-Hee;Im, Eun-Kyung
    • Korean Journal of Digital Imaging in Medicine
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    • v.8 no.1
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    • pp.27-32
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    • 2006

  • The rapid development in digital acquisition technology in radiography has not been accompanied by information regarding optimum radiolographic technique for use with an amorphus silicon flat panel detector. The purpose of our study was to compared imaging characteristics and image quality of an amorphus silicon flat panel detectors for digital chest radiography. All examinations were performed by using an amorphus silicon flat panel detector. Chest radiographs of an chest phantom were obtained with peak kilovoltage values of 60$\sim$150 kVp. Published data ell the effect of x-ray beam energy on imaging characteristics and image qualify when using an amorphus silicon flat panel detector. It is important that radiographers are aware of optimum kVp selection for an amorphus silicon flat panel detector system, particularly for the commonly performed chest examination.

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