title: An exposure indicator for digital radiography: AAPM Task Group 116 (executive summary).
abstract: 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.
authors: Imaging Physics Department #056, Division of Diagnostic Imaging, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030, USA. jshepard@mdanderson.org
authors: S Jeff
authors: SJ
authors: Shepard
authors: Jihong
authors: J
authors: Wang
authors: Michael
authors: M
authors: Flynn
authors: Eric
authors: E
authors: Gingold
authors: Lee
authors: L
authors: Goldman
authors: Kerry
authors: K
authors: Krugh
authors: David L
authors: DL
authors: Leong
authors: Eugene
authors: E
authors: Mah
authors: Kent
authors: K
authors: Ogden
authors: Donald
authors: D
authors: Peck
authors: Ehsan
authors: E
authors: Samei
authors: Jihong
authors: J
authors: Wang
authors: Charles E
authors: CE
authors: Willis
mesh_terms: D000535:Aluminum; D000818:Animals; D001331:Automation; D002138:Calibration; D003198:Computer Simulation; D003300:Copper; D005246:Feedback; D006801:Humans; D008327:Mammography / Q000295:instrumentation / Q000379:methods / Q000662:veterinary; D017785:Photons; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000295:instrumentation / Q000379:methods; D011856:Radiographic Image Enhancement / Q000295:instrumentation / Q000379:methods; D011861:Radiography, Dental / Q000295:instrumentation / Q000379:methods / Q000662:veterinary; D013902:Radiography, Thoracic / Q000295:instrumentation / Q000379:methods / Q000662:veterinary; D013057:Spectrum Analysis; D014965:X-Rays
chemical_list: D003300:Copper; D000535:Aluminum