Development of a Dynamic Digital Phantom Capable of Modeling Head and Neck Motion
Abstract
Purpose
When positioning patients for head and neck radiation therapy procedures, it can be difficult to position the patient without knowledge of the limits of motion due to physiological constraints caused by the neck vertebrae. This work seeks to develop a dynamic biomechanical digital phantom of the head and neck that enables accurate simulation of head and neck motion with realistic anatomical constraints for use in automated patient positioning in head and neck radiation therapy.
Methods
A dynamic digital phantom was developed to model head and neck motion while enforcing realistic biomechanical constraints. Unlike conventional static phantoms, this model allows patient anatomy to be evaluated across a continuous range of positions, reflecting clinically relevant variations. Biomechanical constraints are applied to limit articulation to physically plausible motions. Multiple approaches were implemented to model these constraints, including predefined limits on rotation and translation about anatomically motivated pivot points, as well as finite element-based simulations of cervical vertebrae motion. Together, these methods constrain surface deformation and articulation in a manner consistent with observed patient anatomy while preserving flexibility in regions prone to motion, such as the neck.
Results
Preliminary testing of this digital phantom shows potential for accurate reproduction of head and neck motion. The imposed biomechanical constraints have been seen to prevent non-physical articulations while allowing clinically relevant variability in posture in early tests. While more development and testing needs to be done to confirm levels of accuracy and applicability, this preliminary model was able to provide realistic constraints when simulating head and neck motion.
Conclusion
This work demonstrates the feasibility and utility of a dynamic digital head and neck phantom incorporating biomechanical constraints, with potential applications in the optimization and validation of patient positioning for radiation therapy. The accuracy of this phantom will be confirmed in future work involving volunteer studies.