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Yeo J, Daurer BJ, Kimanius D, Balakrishnan D, Bepler T, Tan YZ, Loh ND. Ghostbuster: A phase retrieval diffraction tomography algorithm for cryo-EM. Ultramicroscopy 2024; 262:113962. [PMID: 38642481 DOI: 10.1016/j.ultramic.2024.113962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/16/2024] [Accepted: 04/01/2024] [Indexed: 04/22/2024]
Abstract
Ewald sphere curvature correction, which extends beyond the projection approximation, stretches the shallow depth of field in cryo-EM reconstructions of thick particles. Here we show that even for previously assumed thin particles, reconstruction artifacts which we refer to as ghosts can appear. By retrieving the lost phases of the electron exitwaves and accounting for the first Born approximation scattering within the particle, we show that these ghosts can be effectively eliminated. Our simulations demonstrate how such ghostbusting can improve reconstructions as compared to existing state-of-the-art software. Like ptychographic cryo-EM, our Ghostbuster algorithm uses phase retrieval to improve reconstructions, but unlike the former, we do not need to modify the existing data acquisition pipelines.
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Affiliation(s)
- Joel Yeo
- NUS Graduate School for Integrative Sciences and Engineering Programme, National University of Singapore, 119077 Singapore, Singapore; Department of Physics, National University of Singapore, 117551 Singapore, Singapore; Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, 138634 Singapore, Singapore
| | - Benedikt J Daurer
- Center for Bio-Imaging Sciences, National University of Singapore, 117557 Singapore, Singapore; Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK
| | - Dari Kimanius
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK; CZ Imaging Institute, 3400 Bridge Parkway, Redwood City, CA 94065, USA
| | - Deepan Balakrishnan
- Department of Biological Sciences, National University of Singapore, 117558 Singapore, Singapore; Center for Bio-Imaging Sciences, National University of Singapore, 117557 Singapore, Singapore
| | - Tristan Bepler
- Simons Machine Learning Center, New York Structural Biology Center, New York, NY, USA
| | - Yong Zi Tan
- Department of Biological Sciences, National University of Singapore, 117558 Singapore, Singapore; Center for Bio-Imaging Sciences, National University of Singapore, 117557 Singapore, Singapore; Disease Intervention Technology Laboratory (DITL), Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, 138648 Singapore, Singapore; Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, 138673 Singapore, Singapore
| | - N Duane Loh
- NUS Graduate School for Integrative Sciences and Engineering Programme, National University of Singapore, 119077 Singapore, Singapore; Department of Physics, National University of Singapore, 117551 Singapore, Singapore; Department of Biological Sciences, National University of Singapore, 117558 Singapore, Singapore; Center for Bio-Imaging Sciences, National University of Singapore, 117557 Singapore, Singapore.
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Gureyev TE, Quiney HM, Allen LJ. Method for virtual optical sectioning and tomography utilizing shallow depth of field. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2022; 39:936-947. [PMID: 36215455 DOI: 10.1364/josaa.455682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/10/2022] [Indexed: 06/16/2023]
Abstract
A method is proposed for high-resolution, three-dimensional reconstruction of internal structures of objects from planar transmission images. The described approach can be used with any form of radiation or matter waves, in principle, provided that the depth of field is smaller than the thickness of the sample. The physical optics basis for the method is elucidated, and the reconstruction algorithm is presented in detail. A simulated example demonstrates an application of the method to three-dimensional electron transmission imaging of a nanoparticle under realistic radiation dose and spatial resolution constraints. It is envisaged that the method can be applicable in high-resolution transmission electron microscopy, soft x-ray microscopy, ultrasound imaging, and other areas.
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Gureyev TE, Paganin DM, Brown HG, Quiney HM, Allen LJ. A Method for High-Resolution Three-Dimensional Reconstruction with Ewald Sphere Curvature Correction from Transmission Electron Images. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-17. [PMID: 35485646 DOI: 10.1017/s1431927622000630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A method for three-dimensional reconstruction of objects from defocused images collected at multiple illumination directions in high-resolution transmission electron microscopy is presented. The method effectively corrects for the Ewald sphere curvature by taking into account the in-particle propagation of the electron beam. Numerical simulations demonstrate that the proposed method is capable of accurately reconstructing biological molecules or nanoparticles from high-resolution defocused images under conditions achievable in single-particle electron cryo-microscopy or electron tomography with realistic radiation doses, non-trivial aberrations, multiple scattering, and other experimentally relevant factors. The physics of the method is based on the well-known Diffraction Tomography formalism, but with the phase-retrieval step modified to include a conjugation of the phase (i.e., multiplication of the phase by a negative constant). At each illumination direction, numerically backpropagating the beam with the conjugated phase produces maximum contrast at the location of individual atoms in the molecule or nanoparticle. The resultant algorithm, Conjugated Holographic Reconstruction, can potentially be incorporated into established software tools for single-particle analysis, such as, for example, RELION or FREALIGN, in place of the conventional contrast transfer function correction procedure, in order to account for the Ewald sphere curvature and improve the spatial resolution of the three-dimensional reconstruction.
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Affiliation(s)
- Timur E Gureyev
- ARC Centre in Advanced Molecular Imaging, School of Physics, The University of Melbourne, Parkville, VIC3010, Australia
- School of Physics and Astronomy, Monash University, Clayton, VIC3800, Australia
| | - David M Paganin
- School of Physics and Astronomy, Monash University, Clayton, VIC3800, Australia
| | - Hamish G Brown
- ARC Centre in Advanced Molecular Imaging, School of Physics, The University of Melbourne, Parkville, VIC3010, Australia
| | - Harry M Quiney
- ARC Centre in Advanced Molecular Imaging, School of Physics, The University of Melbourne, Parkville, VIC3010, Australia
| | - Leslie J Allen
- ARC Centre in Advanced Molecular Imaging, School of Physics, The University of Melbourne, Parkville, VIC3010, Australia
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