Hiroyuki Tashiro

Publications (2)0 Total impact

• Article: [Objective evaluation of visual fatigue for reading of radiographs displayed on medical-grade liquid-crystal displays].

  Keita Takahashi, Junji Morishita, Hiroyuki Tashiro, Yasuhiko Nakamura
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  ABSTRACT: The aim of this study was to evaluate visual fatigue objectively by measuring accommodation time and critical fusion frequency (CFF) before and after reading posteroanterior chest radiographs displayed on medical-grade liquid-crystal displays (LCDs) under different monitor conditions. A color LCD (500, 170 cd/m²) and a monochrome LCD (500 cd/m²) were used in this study. Six observers independently kept reading the radiographs for two hours to understand various lung nodules in the "Fatigue Session". Objective visual fatigue was measured by using the accommodation device and the CFF meter before and after the Fatigue Session. The ambient lighting of the laboratory was set at 35 lux. Both the accommodation time and the CFF between before and after the Fatigue Session indicated statistically significant differences (p<0.05). Our results on accommodation time and CFF before and after reading the radiographs on medical-grade LCDs indicated that visual fatigue could be evaluated objectively.
  Nippon Hoshasen Gijutsu Gakkai zasshi 11/2010; 66(11):1416-22.
• Article: [Effect of ambient light variations on luminance ratio of CRT monitor and image contrast in ultrasonography].

  Shiro Hatanaka, Junji Morishita, Akiko Chishaki, Yukari Noguchi, Eisaku Hokazono, Yoko Komiya, Yoshiharu Higashida, Yoshinobu Shimanoe, Kunio Nakamura, Hiroyuki Tashiro
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  ABSTRACT: Variation in the luminance ratio of a cathode ray tube(CRT)monitor and the ultrasonographic images at different levels of ambient light(0-150 lux)was investigated to obtain optimum ambient light in the ultrasonography suite. The maximum and minimum luminances of test patterns and ultrasonographic images were measured after three technicians independently optimized the brightness and contrast of the CRT monitor and ultrasonographic images at different levels of ambient light. Furthermore, the luminance ratio was calculated from the maximum luminance divided by the minimum luminance. When ambient light increased, it was difficult for the technicians to optimize the brightness and contrast settings of the CRT monitor to maintain a high luminance ratio at 0 lux. The luminance ratio decreased rapidly as ambient light increased up to 20 lux. However, the luminance ratio decreased gradually when ambient light was higher than 20 lux. It is necessary to take into consideration the ambient light to maintain a high luminance ratio of ultrasonographic images.
  Nippon Hoshasen Gijutsu Gakkai zasshi 11/2009; 65(11):1512-8.