GPU Accelerated Real Time kV/MV Dose Computation

We address GPU-accelerated dose computation using superposition/convolution with both a modern dual-source MV model and an analytical kV source model. We achieved a speed-up of 80-142x over a highly optimized CPU implementation. The kV source calculates the analytical fluence at each voxel. The primary MV source supports both focused and rounded MLC leaf ends. The extra-focal MV source is modelled as a discretized, isotropic area source and incorporates leaf height effects. The spectral and attenuation effects of static beam modifiers were integrated into each source’s spectral function. The total energy released per unit mass (TERMA) computation used back-projection with optional exact multi-spectral attenuation. Superposition/convolution was implemented using the inverse cumulative-cumulative kernel and exact radiological path ray-tracing with optional kernel tilting. Two superposition variants were implemented and benchmarked. Multi-resolution superposition approximates true, solid angle raytracing. Arc superposition increases the relative temporal TERMA sampling, which increases computation efficiency.