An efficient point kernel method for rapid dose evaluation in dynamic virtual environment

Rapid and accurate evaluation of gamma radiation dose in dynamic virtual environments is crucial for radiation protection and safety assessment. The point kernel method has been widely used for rapid dose calculation due to its high efficiency. However, the 'point kernel calculations (PKCs) count' is defined as the product of the point kernels number and the counting grids number. Consequently, when either the number of point kernels generated from the discretised radiation source or the number of counting grids in the space becomes large, the time consumption increases significantly. This issue is further exacerbated when the geometric model is no longer a regular geometry describable by mathematical formulas but rather an arbitrary 3D model in a virtual environment, where the cost of ray tracing grows substantially. To address this challenge, an efficient computational approach is proposed and a high-performance point kernel code, PLSPK, is developed in this work. The main features of PLSPK include using triangular mesh models as geometric representations to handle arbitrary shapes, and optimising the ray-tracing process through the application of the maximised-parallelism bounding volume hierarchy technology, enabling rapid selection of target triangles for ray tracing in complex scenes. Furthermore, by leveraging graphics processing unit parallel computation, the code significantly accelerates large-scale PKC in gamma radiation fields, allowing PLSPK to meet the demand for continuous rapid updates of radiation field in dynamic environments. Compared with serial implementations, the acceleration achieved by PLSPK becomes more pronounced as the PKC count (PKC count) increases, when the PKC count reaches 1E + 06, the speedup is approximately 2000×, with small impact from scene complexity. Accuracy validation against existing point kernel codes and the Monte Carlo particle transport program MCNP demonstrates that PLSPK provides reliable dose estimations. These features make PLSPK a reliable tool for high-efficiency gamma radiation field calculation in complex dynamic virtual environments.