Quantum Decoherence Tomography with Entangled 511 Kev Photon Pairs for Image-Guided Radiotherapy
Abstract
Purpose
Real-time, high-precision monitoring of tumor anatomy and microenvironment remains a critical unmet need in radiotherapy. Recent experimental studies have demonstrated that 511 keV photon pairs produced during positron annihilation are quantum entangled. Here, we propose Quantum Decoherence Tomography (QDT), a novel imaging paradigm that exploits changes in entanglement coherence as a contrast mechanism to probe tissue structure and dynamics during radiotherapy.
Methods
QDT leverages coincidence detection of entangled 511 keV photon pairs generated via positron annihilation processes occurring in radiotherapy-relevant environments, including external positron sources and linear accelerator–induced pair production pathways. Angularly resolved coincidence timing measurements are used to quantify decoherence metrics such as entanglement visibility, timing jitter, and polarization or momentum correlation degradation. These metrics are mapped tomographically to infer sub-voxel tissue heterogeneity and microenvironmental changes. The approach builds on recent experimental demonstrations of entangled annihilation photons and extends them to high-flux, clinically relevant geometries using detector arrays with ≤75 ps coincidence timing resolution and enhanced Compton background rejection.
Results
Monte Carlo and phantom-based simulations indicate that QDT can provide micron-scale localization sensitivity and detect subtle microstructural changes beyond conventional PET or CT. Decoherence signatures are predicted to correlate with tissue density gradients, anisotropy, hypoxia-linked microstructural heterogeneity, and dynamic tumor response during irradiation, supporting potential real-time adaptive radiotherapy guidance. Detector simulations confirm high Compton background rejection (>90%) and robust angularly resolved entanglement measurements under clinically relevant photon fluxes.
Conclusion
Quantum Decoherence Tomography introduces a fundamentally new contrast mechanism for radiotherapy imaging based on quantum coherence loss rather than classical attenuation or scattering. If experimentally validated, QDT could enable real-time tumor microenvironment monitoring and adaptive radiotherapy with unprecedented spatial and temporal resolution, with broader applications in biomedical imaging and quantum-enabled sensing.