Penalized maximum likelihood reconstruction for x‐ray differential phase‐contrast tomography. Issue 1 (22nd December 2015)

• Record Type: Journal Article
• Authors: Brendel, Bernhard; von Teuffenbach, Maximilian; Noël, Peter B.; Pfeiffer, Franz; Koehler, Thomas
• Is Part Of: Medical physics. Volume 43:Issue 1(2016)
• Page Start: 188
• Page End: 194
• Publication Date: 2015-12-22
• Subjects: computerised tomography -- image reconstruction -- iterative methods -- maximum likelihood estimation -- medical image processing; Reconstruction -- X‐ray imaging -- Numerical approximation and analysis -- Probability theory, stochastic processes, and statistics -- Artifacts and distortion; Computerised tomographs -- Biological material, e.g. blood, urine; Haemocytometers -- Digital computing or data processing equipment or methods, specially adapted for specific applications -- Image data processing or generation, in general; differential phase contrast imaging -- iterative reconstruction -- regularized reconstruction; Image reconstruction -- Medical image reconstruction -- Phase retrieval -- Medical image smoothing -- Medical X‐ray imaging -- X‐ray scattering -- Medical image artifacts -- X‐ray imaging -- Image sensors; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4938067
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: The purpose of this work is to propose a cost function with regularization to iteratively reconstruct attenuation, phase, and scatter images simultaneously from differential phase contrast (DPC) acquisitions, without the need of phase retrieval, and examine its properties. Furthermore this reconstruction method is applied to an acquisition pattern that is suitable for a DPC tomographic system with continuously rotating gantry (sliding window acquisition), overcoming the severe smearing in noniterative reconstruction. Methods: We derive a penalized maximum likelihood reconstruction algorithm to directly reconstruct attenuation, phase, and scatter image from the measured detector values of a DPC acquisition. The proposed penalty comprises, for each of the three images, an independent smoothing prior. Image quality of the proposed reconstruction is compared to images generated with FBP and iterative reconstruction after phase retrieval. Furthermore, the influence between the priors is analyzed. Finally, the proposed reconstruction algorithm is applied to experimental sliding window data acquired at a synchrotron and results are compared to reconstructions based on phase retrieval. Results: The results show that the proposed algorithm significantly increases image quality in comparison to reconstructions based on phase retrieval. No significant mutual influence between the proposed independent priors could be observed. Further it could be illustrated that the iterative reconstruction of a sliding window acquisition results in images with substantially reduced smearing artifacts. Conclusions: Although the proposed cost function is inherently nonconvex, it can be used to reconstruct images with less aliasing artifacts and less streak artifacts than reconstruction methods based on phase retrieval. Furthermore, the proposed method can be used to reconstruct images of sliding window acquisitions with negligible smearing artifacts.