Virtual Human Simulation Framework

The objectives of the initial project year were to:

1. Aggregate and present research on space flight adaptations and medical conditions prioritized by Exploration Medical Capabilities (ExMC).

2. Develop virtual astronauts and environments to visualize space adaptations and medical conditions.

3. Create ultrasound simulation technologies for image acquisition and diagnostic training.

4. Investigate ways to support just-in-time training for urgent and emergency care procedures.

Level Ex worked with TRISH (Translational Research Institute for Space Health) and NASA during the initial project year to research medical conditions and adaptations of concern and develop a data driven Virtual Human Simulator platform that provides a foundation for future development of medical training and real-time guidance solutions. The Level Ex team researched six principal topic areas of biological systems covering cardiovascular, airway, thoracoabdominal, musculoskeletal, neuro-ocular, and cerebrospinal fluid (CSF) adaptations and conditions. Dozens of subject matter experts, researchers, flight surgeons, physician astronauts, and other key stakeholders within TRISH, NASA, and supporting organizations were interviewed to discuss medical conditions and adaptations, and identify short-term and long-term goals for the advancement of clinical decision support and training solutions to support future crewed missions. The initial research and feedback informed the refinement of project objectives and the development of the Virtual Human Simulator platform prototype software. The completion of these objectives led to the successful development and delivery of the VHS platform prototype, which consists of two primary components: the Anatomy Viewer and the Clinical Training Scenario. The Anatomy Viewer component of VHS platform prototype provides users with a robust and scalable framework for the aggregation and visualization of data from space flight medical research studies, terrestrial medical research, and best practice guidelines. The Anatomy Viewer content is informed by medical conditions identified in the NASA Summary of Human Risk of Spaceflight and Exploration Medical Conditions list. Medical content from cardiovascular, ocular, and pulmonary research topic areas was incorporated into the Anatomy Viewer in the first year. Specific conditions were selected, based upon input from SME interviews, for additional visual content development and inclusion into the initial iteration:

- Vasodilation associated with microgravity fluid shifts and potential IJV Thrombosis.

- Spaceflight Associated Neuro-ocular Syndrome (SANS).

- Cardiac rhythm problems and changes in the shape of the heart due to prolonged microgravity exposure, specifically atrial fibrillation.

- Adverse health effects due to host-microorganism interaction, specifically respiratory infections: Bronchitis.

The NASA Exploration Medical Conditions list currently identifies more than one hundred medical conditions of concern for manned space flight exploration missions. The Anatomy Viewer is extensible to include textual and visual medical content for all one hundred or more ExMC conditions, and content can be updated as new information becomes available. One of the future goals for the project is to provide crews with a version of the Anatomy Viewer that contains medical reference content for all of the conditions and risks identified by ExMC. The Clinical Training Scenario component of the VHS platform prototype provides users with an integrated clinical training environment with clinical decision mechanics, virtual astronaut models, and novel ultrasound simulation technology. It is extensible and can be populated with modules specific to each medical condition in the ExMC Medical Conditions List or any other clinical scenario of interest to mitigate human systems risks to future long duration manned space flight missions. The first clinical scenario developed within the VHS prototype is an inflight diagnostic and procedural intervention scenario related to occlusive thrombus in the internal jugular vein due to chronic exposure to space flight conditions. One of the most substantial technological innovations developed during the first project year is a real-time virtual ultrasound simulation and volumetric anatomical reference modeling process. Level Ex's R&D team developed some of the most advanced real-time ultrasound simulation technology available to date and demonstrated its application within the VHS platform. Features include:

- Physics-based ultrasound simulation including simulated wave propagation and backscatter, which produces realistic interactions with a range of participating media.

- Real-time rendering through highly optimized GPU acceleration.

- Realistic ultrasound artifacts including ringdown and acoustic shadowing. These artifacts emerge from the mathematical properties of the simulation, as opposed to artifacts added on as a special-case visual effect.

- Validation against phantom tissue analogs used to test and calibrate real transducer arrays.

- Ability to dynamically generate realistic ultrasound images from voxelized patient data.

During the first year of the VHS project the Level Ex team demonstrated the ability to adapt existing medical research and simulation development practices from the commercial terrestrial medical industry to meet the space flight medicine needs identified by NASA stakeholders. During the next phase of the project the Level Ex team seeks to:

1. Investigate the design, development, and integration of technologies to provide a prototype and developmental roadmap for the creation of dynamic and adaptable personalized anatomical models of crew members.

2. Advance the capabilities of the VHS framework prototype developed in year-one to create a remote collaborative environment that allows crew members and flight surgeons to engage in experiential medical practice and procedural scenarios while synchronously interacting with one another from anywhere in the world.