Mr. Mattia Humbel Profile

Mattia Humbel

at Univ of Basel

SPIE Involvement:

Author

Publications (9)

Proceedings Article | 24 October 2024 Poster + Paper

A tomography slice through the entire human brain with less than three micrometer voxels

Mattia Humbel, Felix Beckmann, Julian Moosmann, Hans Deyhle, Georg Schulz, Christine Tanner, Griffin Rodgers, Bert Müller

Proceedings Volume 13152, 1315220 (2024) https://doi.org/10.1117/12.3030304

KEYWORDS: Brain, Voxels, Neuroimaging, Tomography, Image resolution, Spatial resolution, Magnetic resonance imaging, X-rays, Phase retrieval

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Proceedings Article | 23 October 2024 Presentation + Paper

Detection of cardiac-induced motion in murine cerebrospinal fluid space captured in vivo with synchrotron radiation-based microtomography

Mattia Humbel, Marta Girona Alarcón, Willy Kuo, Irene Spera, Britta Bausch, Luca Fardin, Hans Deyhle, Griffin Rodgers, Britta Engelhardt, Steven Proulx, Vartan Kurtcuoglu, Bert Müller, Christine Tanner

Proceedings Volume 13152, 1315214 (2024) https://doi.org/10.1117/12.3028460

KEYWORDS: Image registration, In vivo imaging, Motion detection, Contrast agents, Visual inspection, Gated imaging, Motion measurement

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Proceedings Article | 18 October 2024 Presentation + Paper

Comparison of large-volume imaging approaches using computed tomography

Mattia Humbel, Christine Tanner, Griffin Rodgers, Hans Deyhle, Georg Schulz, Bert Müller

Proceedings Volume 13152, 1315211 (2024) https://doi.org/10.1117/12.3028566

KEYWORDS: Tomography, Brain, Image registration, Anatomy, Voxels, Synchrotrons, Neuroimaging, Image restoration, Computed tomography, Cerebellum

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The acquisition of large tomography volumes, exceeding the typical detector field-of-view, requires advanced acquisition techniques. Current approaches are the tiling of local reconstructed volumes or the tiling in projection space, also known as mosaic tomography. Reconstruction tiling has the advantage that standard reconstruction software can be used and acquisition can be interrupted and resumed relatively easily. The disadvantage is that there is the need for volume registration and transformation. Projection tiling is faster and more dose efficient, however a custom reconstruction pipeline is required, registration in projection space is challenging due to lower contrast, and there is a high sensitivity to mechanical instabilities. In this work we propose a third, hybrid approach, to profit from the advantages of projection tiling, but limit the risks. The volume to be imaged is covered by overlapping cylinders, each corresponding to the reconstructed volume of one mosaic tomogram. The number of rings per cylinder and the total number of cylinders can be tuned to the specimen at hand. We demonstrate this approach for a 2cm-wide section of a human brain stem, imaged at the Anatomix beamline of Synchrotron Soleil, France with 0.65µm voxel size, resulting in reconstructed slices 29,650 voxels wide. For mosaic reconstruction we used our team’s existing pipeline. For stitching of volumes, image registration was performed in the overlap regions. As pairwise displacements between cylinders are not independent, we modified the registration approach to force a consistent solution. The results of the hybrid acquisition in seven tiles with four rings were compared to a pure projection tiling approach with eight rings and to local regions representing reconstruction tiling. In conclusion, we propose an extended field of view acquisition scheme building on the speed and dose efficiency of mosaic acquisition, but relaxing the requirements for mechanical and beam stability.

Proceedings Article | 9 May 2024 Poster + Paper

Hard x-ray nanotomography of dental composites for wide color matching

Dimitrios Tripkis, Mattia Humbel, Hans Deyhle, Georg Schulz, Mario Scheel, Timm Weitkamp, Bert Müller

Proceedings Volume 12944, 129440G (2024) https://doi.org/10.1117/12.3012813

KEYWORDS: Composites, X-rays, X-ray microscopy, Transmittance, Particles, Optical transmission, Matrices, Synchrotrons, Dentistry, Dental materials

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Caries affects billions of individuals worldwide, thus pointing out the importance of advancements in restorative dentistry. Dental resin composites yield restorations with satisfying mechanical properties, therefore the focus of development has shifted to accelerated treatments and esthetic aspects. Challenges in matching tooth color arise due to limited options, application changes, and color variations over time. Single-shade composites with the 'chameleon effect' adapt their color to the surrounding enamel by closely matching the tooth's optical spectrum, enhancing color blending. Structural color, based on light interference, contributes to this effect. The study investigates the submicron filler particles' impact on optical properties and the chameleon effect. Four single-shade dental resin composite materials were investigated. Needle-like samples about 100 μm in diameter were prepared and imaged in a scanning electron microscope. Light transmission through the materials for wavelengths between 200 and 900 nm was measured using a spectrophotometer. Three-dimensional nanotomography data were obtained through transmission X-ray microscopy at the ANATOMIX beamline, Synchrotron SOLEIL, France in both absorption and Zernike phase contrast mode with 23 nm voxel size. The real space information was complemented with small-angle X-ray scattering. These experiments revealed substantial differences in the microscopic structure of the materials. In the case of Omnichroma, the filler consists of almost identical spheres with a diameter of 260 nm while Filtek Universal exhibits polydisperse, irregularly shaped fillers. Additionally, Venus Pearl One’s fillers have a polyhedral shape and a wide size distribution. Finally, the setups used did not reveal any clearly identified microstructure of the Chroma Fill composite. Although all investigated materials are known to exhibit the chameleon effect, their differences in micro- and nanostructure call into question previous hypotheses on the chameleon effect’s origin from structural color. While we have now a reasonable understanding of filler morphology, size distribution and spatial arrangement, more information is needed on the exact chemical composition of filler and matrix and their interaction with electromagnetic waves, including possible nonlinear effects.

Proceedings Article | 14 October 2022 Presentation + Paper

Nano-tomography of dental composites with wide color matching

Mattia Humbel, Mario Scheel, Christine Tanner, Griffin Rodgers, Georg Schulz, Corinne Carlucci, Jeannette von Jackowski, Guido Sigron, Andrés Izquierdo, Timm Weitkamp, Bert Müller

Proceedings Volume 12242, 122420Q (2022) https://doi.org/10.1117/12.2635928

KEYWORDS: Composites, Particles, Transmittance, Monte Carlo methods, Refractive index, Optical spheres, Tomography, Polymers, Teeth, Photorefractive polymers, X-ray microscopy, Disordered photonic crystals

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Proceedings Article | 14 October 2022 Presentation + Paper

Hierarchical imaging of African bovid tooth cementum using x-ray microtomography

Adriana Velasco, Christine Tanner, Georg Schulz, Griffin Rodgers, Jeannette von Jackowski, Mattia Humbel, Timm Weitkamp, Henry Bunn, Bert Müller

Proceedings Volume 12242, 122420R (2022) https://doi.org/10.1117/12.2633043

KEYWORDS: Teeth, Cements, Synchrotrons, X-rays, X-ray imaging, Tomography, Visualization, Statistical analysis, Anthropology, Synchrotron x-ray imaging

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Proceedings Article | 20 April 2022 Presentation + Paper

Three-dimensional imaging and analysis of annual layers in tree trunk and tooth cementum

Bert Müller, Muriel Stiefel, Griffin Rodgers, Mattia Humbel, Melissa Osterwalder, Jeannette von Jackowski, Gerhard Hotz, Adriana Velasco Guadarrama, Henry Bunn, Mario Scheel, Timm Weitkamp, Georg Schulz, Christine Tanner

Proceedings Volume 12041, 120410C (2022) https://doi.org/10.1117/12.2615148

KEYWORDS: Teeth, Tomography, Hard x-rays, Image segmentation, Spatial resolution, 3D image processing, X-rays, Visualization

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Proceedings Article | 20 April 2022 Presentation + Paper

Dental composites for wide color matching

Mattia Humbel, Corinne Mattle, Mario Scheel, Ana Diaz, Iwan Jerjen, Robert Lominski, Robert Sterchi, Georg Schulz, Andres Izquierdo, Guido Sigron, Hans Deyhle, Bert Müller

Proceedings Volume 12041, 1204102 (2022) https://doi.org/10.1117/12.2613110

KEYWORDS: Composites, Particles, Data modeling, Optical spheres, X-rays, Scattering, Transmittance, Teeth, X-ray microscopy, Synchrotrons

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