Imagenología CBCT de super-resolución casi isotrópica con un detector de panel plano de doble capa

Background.For medical imaging, usually, it is crucial to have high spatial resolution. Studies have demonstrated that the novel dual-layer flat panel detectors (FPDs) can acquire extra spatial information to enable super-resolution cone beam CT(CBCT) imaging compared to the conventional single-layer FPDs.Objective.The aim of this study is to investigate the feasibility of realizing near-isotropic super-resolution CBCT imaging with a dual-layer flat panel detector.Methods.To retrieve the near-isotropic super-resolution imaging information, a general mathematical signal model that includes the relative shift, namely, Δualong the horizontalu-axis, Δvalong the verticalv-axis, between the two detector pixel arrays and the gap Δdbetween the two detector layers, is established. Afterwards, an recurrent neural network-based deep neural network, named as two-dimensional 2D-suRi-Net, is employed to efficiently retrieve the projections having near-isotropic super-resolution imaging information. Numerical simulations were performed to investigate the impact of the relative shift (Δu, Δv) and the gap Δdunder different scenarios. The real performance of this proposed super-resolution CBCT imaging approach is validated by a pig leg specimen and an intersecting cylinder phantom.Results.It is found that introducing half pixel shift, i.e. Δu= Δv=0.5δdel(δdeldenotes the pixel dimension), between the two detector layers is necessary for super-resolution CBCT imaging, particularly when the detector gap Δdis less than 3 mm. Results demonstrate that the proposed 2D-suRi-Net can effectively retrieve higher spatial resolution information from the acquired low-energy and high-energy projections having lower spatial resolution. Quantitatively, the spatial resolution difference between the reconstructed super-resolution CBCT images on the axial and coronal plane is less than 10%, demonstrating the near-isotropic super-resolution imaging capability of the 2D-suRi-Net method.Conclusion.In summary, this study demonstrates the feasibility of near-isotropic super-resolution CBCT imaging for dual-layer FPD based CBCT imaging systems.