Japanese Journal of Radiology

, Volume 37, Issue 6, pp 437–448 | Cite as

Monitoring of fatigue in radiologists during prolonged image interpretation using fNIRS

  • Takashi NihashiEmail author
  • Takeo Ishigaki
  • Hiroko Satake
  • Shinji Ito
  • Osamu Kaii
  • Yoshine Mori
  • Kazuhiro Shimamoto
  • Hiromichi Fukushima
  • Kojiro Suzuki
  • Hiroyasu Umakoshi
  • Mitsuo Ohashi
  • Fumio Kawaguchi
  • Shinji Naganawa
Original Article



To determine whether functional near-infrared spectroscopy (fNIRS) allows monitoring fatigue in radiologists during prolonged image interpretation.

Materials and methods

Nine radiologists participated as subjects in the present study and continuously interpreted medical images and generated reports for cases for more than 4 h under real clinical work conditions. We measured changes in oxygenated hemoglobin concentrations [oxy-Hb] in the prefrontal cortex using 16-channel fNIRS (OEG16ME, Spectratech) every hour during the Stroop task to evaluate fatigue of radiologists and recorded fatigue scale (FS) as a behavior data.


Two subjects showed a subjective feeling of fatigue and an apparent decrease in brain activity after 4 h, so the experiment was completed in 4 h. The remaining seven subjects continued the experiment up to 5 h. FS decreased with time, and a significant reduction was observed between before and the end of image interpretation. Seven out of nine subjects showed a minimum [oxy-Hb] change at the end of prolonged image interpretation. The mean change of [oxy-Hb] at the end of all nine subjects was significantly less than the maximum during image interpretation.


fNIRS using the change of [oxy-Hb] may be useful for monitoring fatigue in radiologists during image interpretation.


Radiologists Workload Fatigue Spectroscopy Near-infrared 



This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical statement

This study was approved by the Institutional Review Board of Komaki City Hospital and Nagoya Jhohoku Radiology Clinic.

Informed consent

A comprehensive explanation of the experiment was given to subjects before this study and written informed consent was obtained. Authors from multi-institute participant in this study, and each author individually and significantly contributed to the research and the manuscript.


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Copyright information

© Japan Radiological Society 2019

Authors and Affiliations

  • Takashi Nihashi
    • 1
    Email author
  • Takeo Ishigaki
    • 2
  • Hiroko Satake
    • 3
  • Shinji Ito
    • 3
  • Osamu Kaii
    • 2
  • Yoshine Mori
    • 4
  • Kazuhiro Shimamoto
    • 5
  • Hiromichi Fukushima
    • 2
  • Kojiro Suzuki
    • 6
  • Hiroyasu Umakoshi
    • 1
  • Mitsuo Ohashi
    • 7
  • Fumio Kawaguchi
    • 7
  • Shinji Naganawa
    • 3
  1. 1.Department of RadiologyKomaki City HospitalKomakiJapan
  2. 2.Nagoya Jhohoku Radiology ClinicNagoyaJapan
  3. 3.Department of RadiologyNagoya University Graduate School of MedicineNagoyaJapan
  4. 4.Department of RadiologyAnjo Kosei HospitalAnjoJapan
  5. 5.Department of Radiological and Medical Laboratory SciencesNagoya University Graduate School of MedicineNagoyaJapan
  6. 6.Department of RadiologyAichi Medical UniversityNagakuteJapan
  7. 7.Spectratech, Inc.TokyoJapan

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