Designing a Collaborative Immersive Visualization System for Radiation Treatment Planning Teams

We present a visualization design study of creating a collaborative virtual reality (VR) system for radiation treatment planning, with an emphasis on proton therapy. The goal is to support teams of dosimetrists, physicians, and medical physicists as they review and compare multiple possible patient-specific treatment plans, which requires analyzing complex 3D spatial relationships between a radiation dosage volume and anatomical structures. The approach is a novel combination and refinement of interactive visualization techniques including: networked multi-user immersive visualization, interactive volume rendering and slicing with 3D widgets and gestures, superimposed surface rendering with GPU-accelerated curvature-directed lines, smart cursors, teleporting, and avatars. These features are integrated within a workflow that supports three complementary modes of visual data comparison (juxtaposition, interchangeable, and explicit encoding). Results and feedback from multi-year iterative development with users and a summative field deployment in the form of a mock plan-review meeting reveal several advantages relative to current clinical practice and suggest directions for future work.