title: [Investigation of an Optimum Determination Method of Exposure Index for Posterior-Anterior Chest Radiographs Using an Auto Exposure Control].
abstract: Fifty posterior-anterior chest radiographs taken using an auto exposure control were evaluated in order to find an optimum determination method of the exposure index (EI). Four types of the relevant image regions were tested: (a) full image, (b) central 25% area, (c) full image excluding direct x-ray area, and (d) pulmonary area only, whereas four types of the value of interest (VOI) were adopted to each relevant image region: mean, median, mode, and middle. When the target EI was determined as the average of the 50 images, the deviation index (DI) was within ±1.0 only if pulmonary area was selected as the relevant image region, with the VOI of mean, median, and middle. This result strongly suggests that pulmonary area should be selected as the relevant image region of an EI when an auto exposure control is used.
authors.affiliation: Department of Radiology, Kitasato University Medical Center.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yanagita
authors.forename: Masato
authors.initials: M
authors.lastname: Imahana
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Gomi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nishiki
mesh_terms: D006801:Humans; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods*; D012984:Software