An incomplete variables truncated conjugate gradient method and permissible region strategy were used for reconstruction. In order to overcome this issue, the authors used the diffusion approximation model to describe the photon propagation in tissues, and employed the sparse regularization method for reconstruction. Photons scattering in biological tissues makes it an ill-posed problem to reconstruct the 3D distribution of the x-ray luminescent sample in the cone beam XLCT. Methods: In the cone beam XLCT system, the cone beam x ray was adopted to illuminate the sample and a highly sensitive CCD camera was utilized to acquire luminescent photons emitted from the sample. more ยป The validity of the imaging strategy has been studied in this paper. The imaging model and reconstruction method are described. In this paper, a novel cone beam x-ray luminescence computed tomography strategy is proposed, which can fully utilize the x-ray dose and shorten the scanning time. This resulted in a relatively long sampling time and relatively low utilization of the x-ray beam. In the previous XLCT system, the sample was irradiated by a sequence of narrow x-ray beams and the x-ray luminescence was measured by a highly sensitive charge coupled device (CCD) camera. Purpose: The appearance of x-ray luminescence computed tomography (XLCT) opens new possibilities to perform molecular imaging by x ray. We then show how this derivation points to new FFT-based implementations for the higher order diffraction tomography algorithms that are currently being = m in diameter. Further, we have reviewed the derivation of the Fourier Diffraction Projection Theorem, which forms the basis of the first-order reconstruction algorithms. We have also reviewed the assumptions made in the first-order Born and Rytov approximations for diffraction tomography. The first-order Rytov approximation is valid with essentially no constraint on the size of the cylinder however, the relative refractive index must be less than a few percent. The simulations establish the first-order Born approximation to be valid for objects where the product of the relative refractive index and the diameter of the cylinder is less than 0.35 lambda. These computer simulations were conducted on single cylinders, since in this case analytical expressions are available for the exact scattered fields. In this paper, the results of computer simulations used to determine the domains of applicability of the first-order Born and Rytov approximations in diffraction tomography for cross-sectional (or three-dimensional) imaging of biosystems are shown.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |