It is important to investigate eye tracking gaze points of experts, in order to assist trainees in understanding of
image interpretation process. We investigated gaze points of CT colonography (CTC) interpretation process, and
analyzed the difference in gaze points between experts and trainees. In this study, we attempted to understand how
trainees can be improved to a level achieved by experts in viewing of CTC.
We used an eye gaze point sensing system, Gazefineder (JVCKENWOOD Corporation, Tokyo, Japan), which can
detect pupil point and corneal reflection point by the dark pupil eye tracking. This system can provide gaze points
images and excel file data. The subjects are radiological technologists who are experienced, and inexperienced in reading
CTC. We performed observer studies in reading virtual pathology images and examined observer’s image interpretation
process using gaze points data. Furthermore, we examined eye tracking frequency analysis by using the Fast Fourier
We were able to understand the difference in gaze points between experts and trainees by use of the frequency
analysis. The result of the trainee had a large amount of both high-frequency components and low-frequency components.
In contrast, both components by the expert were relatively low. Regarding the amount of eye movement in every 0.02
second we found that the expert tended to interpret images slowly and calmly. On the other hand, the trainee was moving
eyes quickly and also looking for wide areas.
We can assess the difference in the gaze points on CTC between experts and trainees by use of the eye gaze point
sensing system and based on the frequency analysis. The potential improvements in CTC interpretation for trainees can
be evaluated by using gaze points data.