Tetrahedron beam imaging with a multi‐pixel thermionic emission X‐ray source and a photon‐counting detector: A benchtop experimental study

Abstract

Purpose A tetrahedron beam (TB) x-ray system with a linear x-ray source array and a linear detector array positioned orthogonal to each other may overcome the x-ray scattering problem of traditional cone-beam x-ray systems. We developed a TB imaging benchtop system using a linear array x-ray source to demonstrate the principle and benefits of TB imaging. Methods A multi-pixel thermionic emission x-ray (MPTEX) source with 48 focal spots in 4 mm spacing was developed in-house. The x-ray beams are collimated to a stack of fan beams that are converged to a 6 mm wide multi-row photon-counting detector (PCD). The data collected with a sequential scan of the sources at a fixed view angle were synthesized to a 2D radiography image by a shift-and-add algorithm. The data collected with a full rotation of the system were reconstructed into 3D tetrahedron beam CT (TBCT) images using an FDK-based CT algorithm modified for the TB geometry. Results With an 18.8 cm long source array and a 35 cm long detector array, the TB benchtop system provides a 25 cm cross-sectional and 8 cm axial field of view (FOV). The scatter-to-primary ratio (SPR) was approximately 17% for TB, as compared with 120% for cone beam geometry. The TBCT system enables reconstructions in two-dimensional radiography and three-dimensional volumetric CT. The TBCT images were free of “cupping” artifacts and have similar image quality as diagnostic helical CT. Conclusions A TB imaging benchtop imaging system was successfully developed with MPTEX source and PCD. Phantom and animal cadaver imaging demonstrated that the TB system can produce satisfactory radiographic x-ray images and 3D CT images with image quality comparable to diagnostic helical CTs. This article is protected by copyright. All rights reserved