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An exposure indicator for digital radiography: AAPM Task Group 116 (Executive Summary)
Author(s) -
Shepard S. Jeff,
Wang Jihong,
Flynn Michael,
Gingold Eric,
Goldman Lee,
Krugh Kerry,
Leong David L.,
Mah Eugene,
Ogden Kent,
Peck Donald,
Samei Ehsan,
Wang Jihong,
Willis Charles E.
Publication year - 2009
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3121505
Subject(s) - image quality , digital radiography , radiography , digital imaging , computed radiography , brightness , detector , medical physics , medical imaging , nuclear medicine , automatic exposure control , medicine , dosimetry , computer vision , digital image , computer science , image processing , artificial intelligence , optics , radiology , physics , image (mathematics)
Digital radiographic imaging systems, such as those using photostimulable storage phosphor, amorphous selenium, amorphous silicon, CCD, and MOSFET technology, can produce adequate image quality over a much broader range of exposure levels than that of screen/film imaging systems. In screen/film imaging, the final image brightness and contrast are indicative of over‐ and underexposure. In digital imaging, brightness and contrast are often determined entirely by digital postprocessing of the acquired image data. Overexposure and underexposures are not readily recognizable. As a result, patient dose has a tendency to gradually increase over time after a department converts from screen/film‐based imaging to digital radiographic imaging. The purpose of this report is to recommend a standard indicator which reflects the radiation exposure that is incident on a detector after every exposure event and that reflects the noise levels present in the image data. The intent is to facilitate the production of consistent, high quality digital radiographic images at acceptable patient doses. This should be based not on image optical density or brightness but on feedback regarding the detector exposure provided and actively monitored by the imaging system. A standard beam calibration condition is recommended that is based on RQA5 but uses filtration materials that are commonly available and simple to use. Recommendations on clinical implementation of the indices to control image quality and patient dose are derived from historical tolerance limits and presented as guidelines.