title: User Interaction in Semi-Automatic Segmentation of Organs at Risk: a Case Study in Radiotherapy.
abstract: Accurate segmentation of organs at risk is an important step in radiotherapy planning. Manual segmentation being a tedious procedure and prone to inter- and intra-observer variability, there is a growing interest in automated segmentation methods. However, automatic methods frequently fail to provide satisfactory result, and post-processing corrections are often needed. Semi-automatic segmentation methods are designed to overcome these problems by combining physicians' expertise and computers' potential. This study evaluates two semi-automatic segmentation methods with different types of user interactions, named the "strokes" and the "contour", to provide insights into the role and impact of human-computer interaction. Two physicians participated in the experiment. In total, 42 case studies were carried out on five different types of organs at risk. For each case study, both the human-computer interaction process and quality of the segmentation results were measured subjectively and objectively. Furthermore, different measures of the process and the results were correlated. A total of 36 quantifiable and ten non-quantifiable correlations were identified for each type of interaction. Among those pairs of measures, 20 of the contour method and 22 of the strokes method were strongly or moderately correlated, either directly or inversely. Based on those correlated measures, it is concluded that: (1) in the design of semi-automatic segmentation methods, user interactions need to be less cognitively challenging; (2) based on the observed workflows and preferences of physicians, there is a need for flexibility in the interface design; (3) the correlated measures provide insights that can be used in improving user interaction design.
authors.affiliation: Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628CE, Delft, The Netherlands.
authors.forename: Anjana
authors.initials: A
authors.lastname: Ramkumar
authors.affiliation: Aquilab, Loos-les-Lille, Lille, France.
authors.forename: Jose
authors.initials: J
authors.lastname: Dolz
authors.affiliation: Aquilab, Loos-les-Lille, Lille, France.
authors.forename: Hortense A
authors.initials: HA
authors.lastname: Kirisli
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Adebahr
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Schimek-Jasch
authors.affiliation: Department of Radiation Oncology, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Ursula
authors.initials: U
authors.lastname: Nestle
authors.affiliation: Aquilab, Loos-les-Lille, Lille, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Massoptier
authors.affiliation: Department of Medical Informatics, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Edit
authors.initials: E
authors.lastname: Varga
authors.affiliation: Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628CE, Delft, The Netherlands.
authors.forename: Pieter Jan
authors.initials: PJ
authors.lastname: Stappers
authors.affiliation: Department of Medical Informatics, Erasmus MC, Rotterdam, The Netherlands.|Faculty of Applied Science, Delft University of Technology, Delft, The Netherlands.
authors.forename: Wiro J
authors.initials: WJ
authors.lastname: Niessen
authors.affiliation: Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628CE, Delft, The Netherlands. Y.Song@tudelft.nl.
authors.forename: Yu
authors.initials: Y
authors.lastname: Song
mesh_terms: D000465:Algorithms; D006801:Humans; D021621:Imaging, Three-Dimensional; D015588:Observer Variation; D058958:Organs at Risk / Q000000981:diagnostic imaging*; D010363:Pattern Recognition, Automated; D011878:Radiotherapy; D015203:Reproducibility of Results
keywords: Correlations; Evaluation; Human-computer interaction; Organs at risk; Radiotherapy; Semi-automatic segmentation