Human–Computer Interaction in Radiotherapy Target Volume Delineation: A Prospective, Multi-institutional Comparison of User Input Devices

Abstract

The purpose of this study was the prospective comparison of objective and subjective effects of target volume region of interest (ROI) delineation using mousekeyboard and pen-tablet user input devices (UIDs). The study was designed as a prospective test/retest sequence, with Wilcoxon signed rank test for matchedpair comparison. Twenty-one physician-observers contoured target volume ROIs on four standardized cases (representative of brain, prostate, lung, and head and neck malignancies) twice: once using QWERTY keyboard/scroll-wheel mouse UID and once with pen-tablet UID (DTX2100, Wacom Technology Corporation, Vancouver, WA, USA). Active task time, ROI manipulation task data, and subjective survey data were collected. One hundred twenty-nine target volume ROI sets were collected, with 62 paired pen-tablet/mouse-keyboard sessions. Active contouring time was reduced using the pen-tablet UID, with mean ± SD active contouring time of 26 ±23 min, compared with 32 ± 25 with the mouse (p ≤ 0.01). Subjective estimation of time spent was also reduced from 31 ±26 with mouse to 27 ± 22 min with the pen (p = 0.02). Task analysis showed ROI correction task reduction (p = 0.045) and decreased panning and scrolling tasks (p < 0.01) with the pen-tablet; drawing, window/ level changes, and zoom commands were unchanged (p = n.s.) Volumetric analysis demonstrated no detectable differences in ROI volume nor intra-or inter-observer volumetric coverage. Fifty-two of 62 (84%) users preferred the tablet for each contouring task; 5 of 62 (8%) denoted no preference, and 5 of 62 (8%) chose the mouse interface. The pen-tablet UID reduced active contouring time and reduced correction of ROIs, without substantially altering ROI volume/coverage.

User Interaction in Semi-Automatic Segmentation of Organs at Risk: a Case Study in Radiotherapy

“…If new input devices were introduced, it would have been difficult to identify the cause of changes in the process and the result. Coen [ 39 ] discussed that HCI input devices may also influence the segmentation. Thus, different types of input devices should be considered after physicians are familiar with this method.…”

“…A variety of usability evaluation methods have been used to detect the usability problems related to technology. They are the following: heuristic evaluation [ 34 ], cognitive walkthrough [ 35 ], cognitive task analysis [ 36 , 37 ], think-aloud protocol [ 38 ], usability surveys [ 39 ], etc. Most of the usability studies include subjective and objective measures, some quantifying the HCI process, others quantifying the result.…”

Evaluation of measures for assessing time-saving of automatic organ-at-risk segmentation in radiotherapy

“…Contouring of organs-at-risk (OARs) and target volumes is an important step in radiation treatment planning [1] , [2] . However, the delineation quality and time spent on contouring strongly depend on the experience of the radiation oncologist or radiotherapy technician (RTT) [3] , [4] .…”

Generating High-Quality Lymph Node Clinical Target Volumes for Head and Neck Cancer Radiation Therapy Using a Fully Automated Deep Learning-Based Approach

“…This manual process is time-consuming and subject to significant inter- and intraobserver variabilities 1 , 2 with reports suggesting that head and neck cancers (HNC) target delineation is both the most time-consuming anatomic site (taking physicians up to 2–3 hours) and subject to the largest variabilities. 3 – 5 Several consensus delineation guidelines have emerged to reduce this variability 6 – 8 ; yet significant variability persists, especially when delineating the head and neck lymph node levels and low-risk target volumes.…”