Quantum walk method improves X-ray scatter simulation for better imaging
QCxSimulation: Scatter-Aware X-Ray Projection Radiography via Discrete-Time Quantum Walks
Emerging Technologies
Summary
X-ray images work better when the effects of photon scattering are accurately simulated, but classical methods require a lot of computing power. The authors developed a new way to simulate X-ray photon movement using quantum computing principles, which can handle all possible photon paths at once. This method can reproduce X-ray images that include complex scattering effects more efficiently. Their work shows promise that quantum computing could speed up and improve X-ray simulation in the future as the technology matures.
X-ray projection radiographyphoton transport simulationquantum computingdiscrete-time quantum walkphotoelectric absorptionCompton scatteringRayleigh scatteringsuperpositionMonte Carlo simulationvirtual imaging
Authors
Anja Heim, Theobald Fuchs, Thomas Lang, Dimitri Prjamkov, Kilian Dremel, Stefan Kasperl, Christoph Heinzl
Abstract
X-ray projection radiography is a non-invasive imaging technique used in medical diagnostics and industrial inspection. The simulation of X-ray projections is commonly used to optimise acquisition protocols and improve image quality before performing costly scans. Classical photon transport simulations that include realistic X-ray scattering physics are computationally expensive because they require the sampling of a large number of distinct scattering paths. This limits the practical exploration of parameter spaces such as beam energy. Quantum computing offers the potential to solve high-dimensional problems faster by making use of quantum properties such as superposition. This work introduces a discrete-time quantum walk algorithm that simulates the transport of X-ray photons through heterogeneous volumes. It approximates the physics of X-ray projection radiography, including processes such as photoelectric absorption and higher-order scattering, including Compton and Rayleigh scattering. The quantum walk encodes all admissible photon paths into a single quantum state, enabling all scattering histories to be propagated simultaneously via the superposition principle. This quantum state representation enables flexible readout of various imaging modalities, including the primary, i.e., unscattered, image, or images exclusively containing Rayleigh and Compton scattering of specified orders. A quantitative comparison with classically computed reference simulations shows that the proposed quantum walk accurately reproduces radiographic projections, given the limitations of the underlying physical model. These results indicate that quantum circuits for X-ray transport can produce accurate radiographic images and imply that, as quantum hardware scales up, these algorithms could outperform classical Monte Carlo-based approaches in large-scale, scatter-aware virtual imaging studies.