title: Retrospective evaluation of exposure index (EI) values from plain radiographs reveals important considerations for quality improvement.
abstract: BACKGROUND
  Following X-ray exposure, radiographers receive immediate feedback on detector exposure in the form of the exposure index (EI).
  
  
  OBJECTIVE
  To identify whether radiographers are meeting manufacturer-recommended EI (MREI) ranges for routine chest, abdomen and pelvis X-ray examinations under a variety of conditions and to examine factors affecting the EI.
  
  
  METHODS
  Data on 5000 adult X-ray examinations including the following variables were collected: examination parameters, EI values, patient gender, date of birth, date and time of examination, grid usage and the presence of implant or prosthesis. Descriptive statistics were used to summarize each data set and the Mann-Whitney U test was used to determine significant differences, with P < 0.05 indicating significance for all tests.
  
  
  RESULTS
  Most examinations demonstrated EI values that were outside the MREI ranges, with significantly higher median EI values recorded for female patient radiographs than those for male patients for all manufacturers, indicating higher detector exposures for all units except for Philips digital radiography (DR), where increased EI values indicate lower exposure (P = 0.01). Median EI values for out of hours radiography were also significantly higher compared with normal working hours for all technologies (P ≤ 0.02). Significantly higher median EI values were demonstrated for Philips DR chest X-rays without as compared to those with the employment of a grid (P = 0.03), while significantly lower median EI values were recorded for Carestream Health computed radiography (CR) chest X-rays when an implant or prosthesis was present (P = 0.02).
  
  
  CONCLUSIONS
  Non-adherence to MREIs has been demonstrated with EI value discrepancies being dependent on patient gender, time/day of exposure, grid usage and the presence of an implant or prosthesis. Retrospective evaluation of EI databases is a valuable tool to assess the need of quality improvement in routine DR.
authors.affiliation: Medical Imaging Optimisation and Perception Group (MIOPeG), Discipline of Medical Radiation Sciences, Faculty of Health Science, University of Sydney Sydney, Australia.
authors.forename: Ursula
authors.initials: U
authors.lastname: Mothiram
authors.affiliation: Medical Imaging Optimisation and Perception Group (MIOPeG), Discipline of Medical Radiation Sciences, Faculty of Health Science, University of Sydney Sydney, Australia.
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Brennan
authors.affiliation: Medical Imaging Optimisation and Perception Group (MIOPeG), Discipline of Medical Radiation Sciences, Faculty of Health Science, University of Sydney Sydney, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Robinson
authors.affiliation: Medical Imaging Optimisation and Perception Group (MIOPeG), Discipline of Medical Radiation Sciences, Faculty of Health Science, University of Sydney Sydney, Australia.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Lewis
authors.affiliation: Department of Clinical Medicine, Trinity College Dublin Dublin, Ireland.
authors.forename: Bernadette
authors.initials: B
authors.lastname: Moran
keywords: Computed radiography (CR); digital radiography (DR); exposure index (EI); plain radiographs; quality improvement