title: Experimental system for measurement of radiologists' performance by visual search task.
abstract: OBJECTIVE
  Detective performance of radiologists for "obvious" targets should be evaluated by visual search task instead of ROC analysis, but visual task have not been applied to radiology studies. The aim of this study was to set up an environment that allows visual search task in radiology, to evaluate its feasibility, and to preliminarily investigate the effect of career on the performance.
  
  
  METHODS
  In a darkroom, ten radiologists were asked to answer the type of lesion by pressing buttons, when images without lesions, with bulla, ground-glass nodule, and solid nodule were randomly presented on a display. Differences in accuracy and reaction times depending on board certification were investigated.
  
  
  RESULTS
  The visual search task was successfully and feasibly performed. Radiologists were found to have high sensitivity, specificity, positive predictive values and negative predictive values in non-board and board groups. Reaction time was under 1 second for all target types in both groups. Board radiologists were significantly faster in answering for bulla, but there were no significant differences for other targets and values.
  
  
  CONCLUSIONS
  We developed an experimental system that allows visual search experiment in radiology. Reaction time for detection of bulla was shortened with experience.
authors.affiliation: Department of Radiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Maeda
authors.forename: Takeharu
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Nakashima
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yokosawa
authors.forename: Naoto
authors.initials: N
authors.lastname: Hayashi
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Masutani
authors.forename: Naoki
authors.initials: N
authors.lastname: Yoshioka
authors.forename: Masaaki
authors.initials: M
authors.lastname: Akahane
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
keywords: Performance; Radiologist; Reaction time; Receiver operating characteristic analysis; Visual search task