Immersive virtual reality (VR) is used for various types of learning content. One fundamental but challenging part of VR applications are suitable interaction techniques. In this work, we use the example of interactive nuclide charts to investigate interaction techniques in VR. For this purpose, four variants of visualising an interactive nuclide chart for decay rows in a VR environment were implemented: The floor-freehand variant offers the possibility to move freely on the chart, the floor-controller variant enables teleportation to nuclides using the controller, the wall-freehand variant uses hand gestures to select nuclides, and the wall-controller variant also uses the controller to select nuclides on the wall. Our user study with 24 participants indicated that the wall-controller variant was favoured in terms of usability and user experience.

Virtual surgical training systems are crucial for enabling mental preparation, supporting decision-making, and improving surgical skills. Many virtual surgical training environments focus only on training for a specific medical skill and take place in a single virtual room. However, surgical education and training include the planning of procedures as well as interventions in the operating room context. Moreover, collaboration among surgeons and other medical professionals is only applicable to a limited extent. This work presents a collaborative VR environment similar to a virtual teaching hospital to support surgical training and interprofessional collaboration in a co-located or remote environment. The environment supports photo-realistic avatars and scenarios ranging from planning to training procedures in the virtual operating room. It includes a lobby, a virtual surgical planning room with four surgical planning stations, laparoscopic liver surgery training with the integration of laparoscopic surgical instruments, and medical training scenarios for interprofessional team training in a virtual operating room. Each component was evaluated by domain experts as well as in a series of user studies, providing insights on usability, usefulness, and potential research directions. The proposed environment may serve as a foundation for future medical training simulators.

We present a VR system that supports the restoration of broken cultural artifacts. As a case study, we demonstrate this approach for the restoration of a funerary monument. Among the challenges of this monument are a large number of 415 fragments, an unknown amount belongs to another artifact, missing pieces prevent a full reconstruction and the preserved fragments vary strongly in size. Our VR system supports the workflow of digital restoration by offering a configurable self-arranging fragment wall. It supports the user to organize all fragments in an overview representation and to identify relevant fragments quickly. For assembly, we implemented a jigsaw approach comprising two sets of manipulation techniques that allow the user to roughly align fragments first in sub-puzzles and precisely assemble them in a second step. The iterative development and assembling process was accompanied by a professional restorer. We report about the insights we gained from this process and how we optimized the VR system according to her requirements and feedback. Within 14 sessions that took 21 hours, the virtual reconstruction was finalized.

We present a Virtual and Augmented Reality multi-user prototype of a learning environment for liver anatomy education. Our system supports various training scenarios ranging from small learning groups to classroom-size education, where students and teachers can participate in virtual reality, augmented reality, or via desktop PCs. In an iterative development process with surgeons and teachers, a virtual organ library was created. Nineteen liver data sets were used comprising 3D surface models, 2D image data, pathology information, diagnosis and treatment decisions. These data sets can interactively be sorted and investigated individually regarding their volumetric and meta information. The three participation modes were evaluated within a user study with surgery lecturers (5) and medical students (5). We assessed the usability and presence using questionnaires. Additionally, we collected qualitative data with semistructured interviews. A total of 435 individual statements were recorded and summarized to 49 statements. The results show that our prototype is usable, induces presence, and potentially support the teaching of liver anatomy and surgery in the future.

Abstract Medical visualizations are highly adapted to a specific medical application scenario. Therefore, many researchers conduct qualitative evaluations with a low number of physicians or medical experts to assess the benefits of their visualization technique. Although this type of research has advantages, it is difficult to reproduce and can be subjectively biased. This makes it problematic to quantify the benefits of a new visualization technique. Quantitative evaluation can objectify research and help bringing new visualization techniques into clinical practice. To support researchers, we present guidelines to quantitatively evaluate medical visualizations, considering specific characteristics and difficulties. We demonstrate the adaptation of these guidelines on the example of comparative aneurysm surface visualizations. We developed three visualization techniques to compare aneurysm volumes. The visualization techniques depict two similar, but not identical aneurysm surface meshes. In a user study with 34 participants and five aneurysm data sets, we assessed objective measures (accuracy and required time) and subjective ratings (suitability and likeability). The provided guidelines and presentation of different stages of the evaluation allow for an easy adaptation to other application areas of medical visualization.