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Forschungsdatenbank PMU-SQQUID

Filtered-backprojection reconstruction for a cone-beam computed tomography scanner with independent source and detector rotations.
Rit, S; Clackdoyle, R; Keuschnigg, P; Steininger, P
MED PHYS. 2016; 43(5): 2344
Originalarbeiten (Zeitschrift)

PMU-Autor/inn/en

Keuschnigg Peter
Steininger Philipp

Abstract

Purpose: A new cone-beam CT scanner for image-guided radiotherapy (IGRT) can independently rotate the source and the detector along circular trajectories. Existing reconstruction algorithms are not suitable for this scanning geometry. The authors propose and evaluate a three-dimensional (3D) filtered-backprojection reconstruction for this situation. Methods: The source and the detector trajectories are tuned to image a field-of-view (FOV) that is offset with respect to the center-of-rotation. The new reconstruction formula is derived from the Feldkamp algorithm and results in a similar three-step algorithm: projection weighting, ramp filtering, and weighted backprojection. Simulations of a Shepp Logan digital phantom were used to evaluate the new algorithm with a 10 cm-offset FOV. A real cone-beam CT image with an 8.5 cm-offset FOV was also obtained from projections of an anthropomorphic head phantom. Results: The quality of the cone-beam CT images reconstructed using the new algorithm was similar to those using the Feldkamp algorithm which is used in conventional cone-beam CT. The real image of the head phantom exhibited comparable image quality to that of existing systems. Conclusions: The authors have proposed a 3D filtered-backprojection reconstruction for scanners with independent source and detector rotations that is practical and effective. This algorithm forms the basis for exploiting the scannerxxxs unique capabilities in IGRT protocols. (C) 2016 American Association of Physicists in Medicine.


Find related publications in this database (Keywords)

image-guided radiotherapy (IGRT)
three-dimensional (3D) imaging
cone-beam computed tomography (CT)
tomographic reconstruction
filtered-backprojection algorithm
offset field-of-view