Usability testing of radiotherapy systems as a medical device evaluation tool to inform hospital procurement decision-making.

PURPOSE: Poor usability designs of radiotherapy systems can contribute to use errors and adverse events. Therefore, we evaluated the usability of two radiotherapy systems through radiation therapists' performance, workload, and experience that can inform hospital procurement decision-making about the selection of appropriate radiotherapy system for radiation therapist use. METHODS: We performed a comparative usability study for two radiotherapy systems through user testing. Thirty radiation therapists participated in our study, in which four typical operational tasks were performed in two tested radiotherapy systems. User performance was measured by task completion time and completion difficulty level. User workloads were measured by perceived and physiological workload using NASA-TLX questionnaires and eye motion data. User experience was measured by the USE questionnaire. RESULTS: Significantly less task completion time and an easier task completion difficulty level were shown with the Varian Trilogy than with the XHA600E. The study results suggest that higher perceived and physiological workloads were experienced with the XHA600E than with the Varian Trilogy. Radiation therapists reported better user experience with the Varian Trilogy than with the XHA600E. Five paired t-tests regarding user performance, user workload, and user experience between the Varian Trilogy and the XHA600E were performed, showing that the Varian Trilogy radiotherapy system has a better usability design than the XHA600E radiotherapy system. CONCLUSIONS: Based on study results, we confirmed that the Varian Trilogy radiotherapy system has a better usability design than the XHA600E radiotherapy system. Furthermore, the study results provide valuable evidence for hospital procurement decision-making regarding the selection of a suitable radiotherapy system for radiation therapists to use.

The usability of ventilator maintenance user interface: A comparative evaluation of user task performance, workload, and user experience.

Poor usability designed of ventilator user interface can easily lead to human error. In this study, we evaluated the usability design of ventilator maintenance user interface and identified problems related to the usability of user interface that could easily cause human error. Sixteen respiratory therapists participated in this usability study. The usability of the ventilator maintenance user interface was evaluated by participants' task performance (task completion time, task error rate), physiological workload (eye-fixation duration) and perceived workload (NASA-TLX), and user experience (questionnaire). For task performance, task completion time and task error rate showed significant differences. For task completion time, significant difference was found when conducting ventilator self-test (p < 0.001), replace the breathing circuit (p = 0.047), and check battery status (p = 0.005). For task error rate, the three ventilators showed significant difference (p = 0.012), and the Serov I showed a significantly higher task error rate than the Boaray 5000D (p = 0.031). For workload, the Serov I was associated with higher physiological and perceived workloads than other ventilators (p < 0.05). For user experience, the Boaray 5000D received better scores among the ventilators in terms of ease to maintain, friendly to maintain, and willingness to use (p < 0.05, respectively). Our study adds available literature for usability evaluation of ventilator maintenance user interface. The results indicate that the maintenance user interface of the Boaray 5000D performed better than the other two tested ventilators. Moreover, the study results also proved that eye-fixation duration can be a reliable tool for evaluating the usability of ventilator user interface.