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Bakenecker AC, Schumacher J, Blümler P, Gräfe K, Ahlborg M, M Buzug T. A concept for a magnetic particle imaging scanner with Halbach arrays. Phys Med Biol 2020; 65:195014. [PMID: 32155606 DOI: 10.1088/1361-6560/ab7e7e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Magnetic particle imaging (MPI) is a new medical imaging technique visualizing the concentration distribution of superparamagnetic nanoparticles used as tracer material. MPI is not yet in clinical routine, since one of the challenges is the upscaling of scanners. Typically, the magnetic fields of MPI scanners are generated electromagnetically, resulting in an immense power consumption but providing high flexibility in terms of adjusting the field strengths and very fast image acquisition rates. Permanent magnets provide high flux densities and do not need any power supply. However, the flux density is not adjustable, and a mechanical movement is slow compared to electromagnetically varying fields. The MPI scanner concept proposed here uses permanent magnets and provides high flexibility, with the possibility to choose between fast overview scanning and detailed image acquisition. By mechanical rotation of magnetic rings in Halbach array configuration, it is possible to adjust the field or gradient strengths. The latter allows for determining the spatial resolution and the size of the field of view. A continuous mechanical rotation defines the coarseness of the scanning trajectory and image acquisition rate. This concept provides a comparable flexibility, as an alternating magnetic field and an adjustable field gradient can be applied as known from electromagnetically driven MPI systems, and therefore yields high potential for an enlarged system. We present the idea of an arrangement of Halbach arrays and how to calculate the generated magnetic fields. Simulations for an exemplary geometry are provided to show the potential of the proposed setup.
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Affiliation(s)
- A C Bakenecker
- Institute of Medical Engineering, University of Luebeck, Ratzeburger Allee 160, 23562 Luebeck, Germany
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Abstract
Magnetic particle imaging visualizes the spatial distribution of superparamagnetic nanoparticles. Because of its key features of excellent sensitivity, high temporal and spatial resolution and biocompatibility of the tracer material it can be used in multiple medical imaging applications. The common reconstruction technique for Lissajous-type trajectories uses a system matrix that has to be previously acquired in a time-consuming calibration scan, leading to long downtimes of the scanning device. In this work, the system matrix is determined by a hybrid approach. Using the hybrid system matrix for reconstruction, the calibration downtime of the scanning device can be neglected. Furthermore, the signal to noise ratio of the hybrid system matrix is much higher, since the size of the required nanoparticle sample can be chosen independently of the desired voxel size. As the signal to noise ratio influences the reconstruction process, the resulting images have better resolution and are less affected by artefacts. Additionally, a new approach is introduced to address the background signal in image reconstruction. The common technique of subtraction of the background signal is replaced by extending the system matrix with an entry that represents the background. It is shown that this approach reduces artefacts in the reconstructed images.
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Affiliation(s)
- A von Gladiss
- Institute of Medical Engineering, University of Luebeck, Luebeck, Germany
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Ahlborg M, Kaethner C, Knopp T, Szwargulski P, Buzug TM. Using data redundancy gained by patch overlaps to reduce truncation artifacts in magnetic particle imaging. Phys Med Biol 2016; 61:4583-4598. [DOI: 10.1088/0031-9155/61/12/4583] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Weber A, Werner F, Weizenecker J, Buzug TM, Knopp T. Artifact free reconstruction with the system matrix approach by overscanning the field-free-point trajectory in magnetic particle imaging. Phys Med Biol 2015; 61:475-87. [PMID: 26682648 DOI: 10.1088/0031-9155/61/2/475] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Magnetic particle imaging is a tracer-based imaging method that utilizes the non-linear magnetization response of iron-oxide for determining their spatial distribution. The method is based on a sampling scheme where a sensitive spot is moved along a trajectory that captured a predefined field-of-view (FOV). However, particles outside the FOV also contribute to the measurement signal due to their rotation and the non-sharpness of the sensitive spot. In the present work we investigate artifacts that are induced by particles not covered by the FOV and show that the artifacts can be mitigated by using a system matrix that covers not only the region of interest but also a certain area around the FOV. The findings are especially relevant when using a multi-patch acquisition scheme where the boundaries of neighboring patches have to be handled.
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Affiliation(s)
- A Weber
- Bruker Biospin MRI GmbH, Rudolf-Plank-Str. 23, 76275 Ettlingen, Germany. Institute of Medical Engineering, University of Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
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Isernhagen CF, Schäfer D, Grass M, Buzug TM. Three-dimensional anisotropic regularization for limited angle tomography. Current Directions in Biomedical Engineering 2015. [DOI: 10.1515/cdbme-2015-0070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AbstractLimited angle tomography is a challenging task in medical imaging. Due to practical limitations during the image acquisition, the sinogram is recorded incompletely and thus the quality of the reconstruction is deteriorated by streak artifacts. These artifacts are characterized by fast changes of the local intensity gradients and increase the total variation (TV). Generally, an energy functional is optimized which leads to a minimized Total Variation Minimization (TVM). As an outcome, noise and artifacts are reduced while edges are preserved. Anyway, often the orientation of the streak artifacts is not considered at all. Therefore, anisotropic regularization is used to reduce noise and distortions under specific directions.
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Affiliation(s)
- C. F. Isernhagen
- 1Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | | | - M. Grass
- 2Philips Research, Hamburg, Germany
| | - T. M. Buzug
- 1Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
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Sitzer A, Aulmann L, Wendlandt R, Handels H, Weyers I, Schulz AP, Buzug TM. Evaluation of local alterations in femoral bone mineral density measured via quantitative CT. Current Directions in Biomedical Engineering 2015. [DOI: 10.1515/cdbme-2015-0081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
The aim of this study was to investigate the accuracy of bone mineral density (BMD) determined by quantitative computed tomography (qCT) based on in situ and ex situ scans of cadavers of variable stature. The influence of surrounding tissue on the quantification of CT images of ex situ scanned femora was investigated in air and in water and compared with the in situ scanned femora. The study showed that the surrounding tissue has an impact on the grey value-based representation of the scanned object as well as on the calibration of BMD, influencing the determination of BMD. Local differences in BMD of up to 17.5% were observed, which might originate from beam hardening artifacts.
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Affiliation(s)
- A. Sitzer
- Biomechanics Laboratory, University Medical Center Schleswig-Holstein, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - L. Aulmann
- Biomechanics Laboratory, University Medical Center Schleswig-Holstein, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - R. Wendlandt
- Biomechanics Laboratory, University Medical Center Schleswig-Holstein, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - H. Handels
- Institute of Medical Informatics, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - I. Weyers
- Institute of Anatomy, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - A. P. Schulz
- Department of Trauma Surgery, BG Trauma Hospital Hamburg, Bergedorfer Straße 10, 21033 Hamburg, Germany
| | - T. M. Buzug
- Institute of Medical Engineering, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
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Wojtczyk H, Bringout G, Tenner W, Graeser M, Grüttner M, Sattel TF, Gräfe K, Haegele J, Duschka RL, Panagiotopoulos N, Vogt FM, Barkhausen J, Buzug TM. Comparison of Open Scanner Designs for Interventional Magnetic Particle Imaging. ACTA ACUST UNITED AC 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-L/bmt-2013-4279/bmt-2013-4279.xml. [PMID: 24042921 DOI: 10.1515/bmt-2013-4279] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Weber M, Erbe M, Bente K, Sattel TF, Buzug TM. Scanner Construction for a Dynamic Field Free Line in Magnetic Particle Imaging. ACTA ACUST UNITED AC 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-L/bmt-2013-4259/bmt-2013-4259.xml. [PMID: 24042929 DOI: 10.1515/bmt-2013-4259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Duschka RL, Wojtczyk H, Panagiotopoulos N, Haegele J, Bringout G, Rahmer J, Bontus C, Buzug TM, Borgert J, Barkhausen J, Vogt FM. Magnetic Particle Imaging (MPI): Sicherheitsmessungen gängiger, interventionell verwendeter Materialien mit gezieltem Focus auf die Materialerwärmung. ROFO-FORTSCHR RONTG 2013. [DOI: 10.1055/s-0033-1346219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Levakhina YM, Müller J, Duschka RL, Vogt F, Barkhausen J, Buzug TM. Weighted simultaneous algebraic reconstruction technique for tomosynthesis imaging of objects with high-attenuation features. Med Phys 2013; 40:031106. [PMID: 23464286 DOI: 10.1118/1.4789592] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE This paper introduces a nonlinear weighting scheme into the backprojection operation within the simultaneous algebraic reconstruction technique (SART). It is designed for tomosynthesis imaging of objects with high-attenuation features in order to reduce limited angle artifacts. METHODS The algorithm estimates which projections potentially produce artifacts in a voxel. The contribution of those projections into the updating term is reduced. In order to identify those projections automatically, a four-dimensional backprojected space representation is used. Weighting coefficients are calculated based on a dissimilarity measure, evaluated in this space. For each combination of an angular view direction and a voxel position an individual weighting coefficient for the updating term is calculated. RESULTS The feasibility of the proposed approach is shown based on reconstructions of the following real three-dimensional tomosynthesis datasets: a mammography quality phantom, an apple with metal needles, a dried finger bone in water, and a human hand. Datasets have been acquired with a Siemens Mammomat Inspiration tomosynthesis device and reconstructed using SART with and without suggested weighting. Out-of-focus artifacts are described using line profiles and measured using standard deviation (STD) in the plane and below the plane which contains artifact-causing features. Artifacts distribution in axial direction is measured using an artifact spread function (ASF). The volumes reconstructed with the weighting scheme demonstrate the reduction of out-of-focus artifacts, lower STD (meaning reduction of artifacts), and narrower ASF compared to nonweighted SART reconstruction. It is achieved successfully for different kinds of structures: point-like structures such as phantom features, long structures such as metal needles, and fine structures such as trabecular bone structures. CONCLUSIONS Results indicate the feasibility of the proposed algorithm to reduce typical tomosynthesis artifacts produced by high-attenuation features. The proposed algorithm assigns weighting coefficients automatically and no segmentation or tissue-classification steps are required. The algorithm can be included into various iterative reconstruction algorithms with an additive updating strategy. It can also be extended to computed tomography case with the complete set of angular data.
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Affiliation(s)
- Y M Levakhina
- Institute of Medical Engineering, University of Lübeck, Lübeck 23562, Germany.
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Duschka RL, Wojtczyk H, Panagiotopoulos N, Hägele J, Bringout G, Rahmer J, Bontus C, Buzug TM, Borgert J, Barkhausen J, Vogt FM. Magnetic Particle Imaging (MPI) meets Katheter und Co. – Temperaturmessungen interventioneller Materialen im Wechselmagnetfeld. ROFO-FORTSCHR RONTG 2012. [DOI: 10.1055/s-0032-1329771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Mang A, Toma A, Schuetz TA, Becker S, Buzug TM. A generic framework for modeling brain deformation as a constrained parametric optimization problem to aid non-diffeomorphic image registration in brain tumor imaging. Methods Inf Med 2012; 51:429-40. [PMID: 23038648 DOI: 10.3414/me11-02-0036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 04/29/2012] [Indexed: 12/16/2022]
Abstract
OBJECTIVES In the present paper a novel computational framework for modeling tumor induced brain deformation as a biophysical prior for non-rigid image registration is described. More precisely, we aim at providing a generic building block for non-rigid image registration that can be used to resolve inherent irregularities in non-diffeomorphic registration problems that naturally arise in serial and cross-population brain tumor imaging studies due to the presence (or progression) of pathology. METHODS The model for the description of brain cancer dynamics on a tissue level is based on an initial boundary value problem (IBVP). The IBVP follows the accepted assumption that the progression of primary brain tumors on a tissue level is governed by proliferation and migration of cancerous cells into surrounding healthy tissue. The model of tumor induced brain deformation is phrased as a parametric, constrained optimization problem. As a basis of comparison and to demonstrate generalizability additional soft constraints (penalties) are considered. A back-tracking line search is implemented in conjunction with a limited memory Broyden-Fletcher-Goldfarb-Shanno (LBFGS) method in order to handle the numerically delicate log-barrier strategy for confining volume change. RESULTS Numerical experiments are performed to test the flexible control of the computed deformation patterns in terms of varying model parameters. The results are qualitatively and quantitatively related to patterns in patient individual magnetic resonance imaging data. CONCLUSIONS Numerical experiments demonstrate the flexible control of the computed deformation patterns. This in turn strongly suggests that the model can be adapted to patient individual imaging patterns of brain tumors. Qualitative and quantitative comparison of the computed cancer profiles to patterns in medical imaging data of an exemplary patient demonstrates plausibility. The designed optimization problem is based on computational tools widely used in non-rigid image registration, which in turn makes the model generally applicable for integration into non-rigid image registration algorithms.
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Affiliation(s)
- A Mang
- Institute of Medical Engineering, University of Luebeck, Ratzeburger Allee, 23562 Luebeck, Germany
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Toma A, Holl-Ulrich K, Becker S, Mang A, Schütz TA, Bonsanto MM, Tronnier V, Buzug TM. A mathematical model to simulate glioma growth and radiotherapy at the microscopic level. BIOMED ENG-BIOMED TE 2012; 57 Suppl 1:/j/bmte.2012.57.issue-s1-O/bmt-2012-4081/bmt-2012-4081.xml. [PMID: 23096329 DOI: 10.1515/bmt-2012-4081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Müller J, Buzug TM. Calculation of Reconstruction Kernels in Computed Tomography. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- J. Müller
- Institute of Medical Engineering, University of Luebeck, Luebeck, Germany
| | - T. M. Buzug
- Institute of Medical Engineering, University of Luebeck, Luebeck, Germany
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Kaethner C, Müller J, Buzug TM. Determining Noise Distribution in Computed Tomography – A Simple Phantom Based Approach. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- C. Kaethner
- Insitute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - J. Müller
- Insitute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - T. M. Buzug
- Insitute of Medical Engineering, University of Lübeck, Lübeck, Germany
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Gollmer ST, Buzug TM. Triangulating Quadrilaterals on the Sphere: Application to Shape Analysis. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- S. T. Gollmer
- Institute of Medical Engineering, University of Lübeck, 23562 Lübeck, Germany
| | - T. M. Buzug
- Institute of Medical Engineering, University of Lübeck, 23562 Lübeck, Germany
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Gollmer ST, Simon M, Bischof A, Barkhausen J, Buzug TM. Towards Segmentation of the Upper Abdomen using a Multi-Object Active Shape Model. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- S. T. Gollmer
- Institute of Medical Engineering, University of Lübeck, 23562 Lübeck, Germany
| | - M. Simon
- University Medical Center Schleswig-Holstein, Campus Lübeck, Clinic for Radiology and Nuclear Medicine, 23562 Lübeck, Germany
| | - A. Bischof
- IMAGE Information Systems Ltd., Research Facilities, London, UK
| | - J. Barkhausen
- University Medical Center Schleswig-Holstein, Campus Lübeck, Clinic for Radiology and Nuclear Medicine, 23562 Lübeck, Germany
| | - T. M. Buzug
- Institute of Medical Engineering, University of Lübeck, 23562 Lübeck, Germany
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Gräfe K, Sattel TF, Lüdtke-Buzug K, Finas D, Borgert J, Buzug TM. An Application Scenario for Single-Sided Magnetic Particle Imaging. ACTA ACUST UNITED AC 2012. [DOI: 10.1515/bmt-2012-4343] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- K. Gräfe
- Institute of Medical Engineering, University of Luebeck, Lübeck, Germany
| | - T. F. Sattel
- Institute of Medical Engineering, University of Luebeck, Lübeck, Germany
| | - K. Lüdtke-Buzug
- Institute of Medical Engineering, University of Luebeck, Lübeck, Germany
| | - D. Finas
- Department of Obstetrics and Gynaecology, University of Luebeck, Lübeck, Germany
| | - J. Borgert
- Phillips Technology GmbH, Innovative Technologies, Research Laboratories, Hamburg, Germany
| | - T. M. Buzug
- Institute of Medical Engineering, University of Luebeck, Lübeck, Germany
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Cordes A, Levakhina YM, Buzug TM. A Method for Validation and Evaluation of Digital Tomosynthesis Reconstruction. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- A. Cordes
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - Y. M. Levakhina
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
- Graduate School for Computing in Medicine and Life Sciences, University of Lübeck, Lübeck, Germany
| | - T. M. Buzug
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
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Mang A, Toma A, Becker S, Schuetz TA, Buzug TM. Fast Explicit Variational Diffusion Registration. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- A. Mang
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - A. Toma
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
- Centre of Excellence for Technology and Engineering in Medicine (TANDEM), Lübeck, Germany
| | - S. Becker
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
- Centre of Excellence for Technology and Engineering in Medicine (TANDEM), Lübeck, Germany
| | - T. A. Schuetz
- Graduate School for Computing in Medicine and Life Sciences, University of Lübeck, Lübeck, Germany
| | - T. M. Buzug
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
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Levakhina YM, Duschka RL, Vogt FM, Barkhausen J, Buzug TM. A Novel Acquisition Scheme for Higher Axial Resolution and Improved Image Quality in Digital Tomosynthesis. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Y. M. Levakhina
- Institute of Medical Engineering, University of Luebeck, Luebeck, Germany
- Graduate School for Computing in Medicine and Life Sciences, University of Luebeck, Luebeck, Germany
| | - R. L. Duschka
- Klinik fuer Radiologie und Nuklearmedizin, Universitaetsklinikum Schleswig-Holstein, Luebeck, Germany
| | - F. M. Vogt
- Klinik fuer Radiologie und Nuklearmedizin, Universitaetsklinikum Schleswig-Holstein, Luebeck, Germany
| | - J. Barkhausen
- Klinik fuer Radiologie und Nuklearmedizin, Universitaetsklinikum Schleswig-Holstein, Luebeck, Germany
| | - T. M. Buzug
- Institute of Medical Engineering, University of Luebeck, Luebeck, Germany
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Hägele J, Rahmer J, Gleich B, Bontus C, Borgert J, Wojtczyk H, Buzug TM, Barkhausen J, Vogt FM. Darstellung von Instrumenten zur Magnetic Particle Imaging (MPI) gesteuerten kardiovaskulären Intervention. ROFO-FORTSCHR RONTG 2012. [DOI: 10.1055/s-0032-1311012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Duschka RL, Bischoff P, May K, Levakhina Y, Buzug TM, Kovacs A, Hunold P, Barkhausen J, Vogt FM. Digitale Tomosynthese - Ein neues Verfahren zur Beurteilung degenerativer Gelenkveränderungen im Vergleich zum konventionellen Röntgen. ROFO-FORTSCHR RONTG 2012. [DOI: 10.1055/s-0032-1311150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Hägele J, Vogt FM, Barkhausen J, Buzug TM, Luedtke-Buzug K. Eisenoxidnanopartikel für Magnetic Particle Imaging (MPI). ROFO-FORTSCHR RONTG 2012. [DOI: 10.1055/s-0032-1311011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Haegele J, Rahmer J, Gleich B, Bontus C, Borgert J, Wojtczyk H, Buzug TM, Barkhausen J, Vogt FM. Darstellung von Instrumenten zur Magnetic Particle Imaging (MPI) gesteuerten kardiovaskulären Intervention. ROFO-FORTSCHR RONTG 2012. [DOI: 10.1055/s-0031-1300903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Becker S, Mang A, Toma A, Schütz TA, Buzug TM. Modelling the Progression of Brain Metastases. BIOMED ENG-BIOMED TE 2012; 57 Suppl 1:/j/bmte.2012.57.issue-s1-O/bmt-2012-4290/bmt-2012-4290.xml. [DOI: 10.1515/bmt-2012-4290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Griese F, Grüttner M, Buzug TM. Extended Field of View in Magnetic Particle Imaging. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Haegele J, Sattel T, Erbe M, Luedtke-Buzug K, Taupitz M, Borgert J, Buzug TM, Barkhausen J, Vogt FM. [Magnetic particle imaging (MPI)]. ROFO-FORTSCHR RONTG 2011; 184:420-6. [PMID: 22198836 DOI: 10.1055/s-0031-1281981] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Magnetic particle imaging (MPI) displays the spatial distribution and concentration of superparamagnetic iron oxides (SPIOs). It is a quantitative, tomographic imaging method with high temporal and spatial resolution and allows work with high sensitivity yet without ionizing radiation. Thus, it may be a very promising tool for medical imaging. In this review, we describe the physical and technical basics and various concepts for clinical scanners. Furthermore, clinical applications such as cardiovascular imaging, interventional procedures, imaging and therapy of malignancies as well as molecular imaging are presented.
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Affiliation(s)
- J Haegele
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Schleswig-Holstein, Lübeck.
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Schierp F, Gollmer ST, Bischof A, Buzug TM, Lücke A, Barkhausen J, Simon M. Geometrische Basisanalyse der Leber und Milz als Referenzmodell für pathologische Formanalysen und automatische Organsegmentierung. ROFO-FORTSCHR RONTG 2011. [DOI: 10.1055/s-0031-1279207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Vogt FM, Biederer S, Simon M, Lüdtke-Buzug K, Knopp T, Sattel TF, Buzug TM, Barkhausen J. Magnetic Particle Imaging: Evaluation unterschiedlicher superparamagnetischer Eisenoxidpartikel für ein neues bildgebendes Verfahren. ROFO-FORTSCHR RONTG 2010. [DOI: 10.1055/s-0030-1268342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Duschka RL, Levakhina Y, Busch LC, Hunold P, Buzug TM, Barkhausen J, Vogt FM. Tomosynthese zur Beurteilung des Handskeletts – technische Möglichkeiten und klinisches Potenzial. ROFO-FORTSCHR RONTG 2010. [DOI: 10.1055/s-0030-1268310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Buzug TM, Sattel TF, Erbe M, Biederer S, Borgert J, Finas D, Dietrich K, Vogt F, Barkhausen J, Lüdtke-Buzug K, Knopp T. Alternative Spulentopologien für Magnetic-Particle-Imaging. ROFO-FORTSCHR RONTG 2010. [DOI: 10.1055/s-0030-1268341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Lindemann A, Lüdtke-Buzug K, Hüsing B, Pries R, Buzug TM, Wollenberg B. Nanoparticel labelling of stem cell populations in head and neck cancer. J Stem Cells Regen Med 2010; 6:143. [PMID: 24693151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Affiliation(s)
- A Lindemann
- University of Lübeck, Otorhinolaryngology , Lübeck, Germany
| | - K Lüdtke-Buzug
- University of Lübeck, Otorhinolaryngology , Lübeck, Germany
| | - B Hüsing
- University of Lübeck, Otorhinolaryngology , Lübeck, Germany
| | - R Pries
- University of Lübeck, Otorhinolaryngology , Lübeck, Germany
| | - T M Buzug
- University of Lübeck, Otorhinolaryngology , Lübeck, Germany
| | - B Wollenberg
- University of Lübeck, Otorhinolaryngology , Lübeck, Germany
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Knopp T, Rahmer J, Sattel TF, Biederer S, Weizenecker J, Gleich B, Borgert J, Buzug TM. Weighted iterative reconstruction for magnetic particle imaging. Phys Med Biol 2010. [DOI: 10.1088/0031-9155/55/8/c01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Vogt FM, Biederer S, Simon M, Lüdtke-Buzug K, Knopp T, Sattel TF, Buzug TM, Barkhausen J. Magnetic Particle Imaging: Evaluation unterschiedlicher superparamagnetischer Eisenoxidpartikel für ein neues bildgebendes Verfahren. ROFO-FORTSCHR RONTG 2010. [DOI: 10.1055/s-0030-1252832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Knopp T, Rahmer J, Sattel TF, Biederer S, Weizenecker J, Gleich B, Borgert J, Buzug TM. Weighted iterative reconstruction for magnetic particle imaging. Phys Med Biol 2010; 55:1577-89. [PMID: 20164532 DOI: 10.1088/0031-9155/55/6/003] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Magnetic particle imaging (MPI) is a new imaging technique capable of imaging the distribution of superparamagnetic particles at high spatial and temporal resolution. For the reconstruction of the particle distribution, a system of linear equations has to be solved. The mathematical solution to this linear system can be obtained using a least-squares approach. In this paper, it is shown that the quality of the least-squares solution can be improved by incorporating a weighting matrix using the reciprocal of the matrix-row energy as weights. A further benefit of this weighting is that iterative algorithms, such as the conjugate gradient method, converge rapidly yielding the same image quality as obtained by singular value decomposition in only a few iterations. Thus, the weighting strategy in combination with the conjugate gradient method improves the image quality and substantially shortens the reconstruction time. The performance of weighting strategy and reconstruction algorithms is assessed with experimental data of a 2D MPI scanner.
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Affiliation(s)
- T Knopp
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany.
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Knopp T, Biederer S, Sattel T, Weizenecker J, Gleich B, Borgert J, Buzug TM. Trajectory analysis for magnetic particle imaging. Phys Med Biol 2008; 54:385-97. [DOI: 10.1088/0031-9155/54/2/014] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Buzug TM, Hering P, Bongartz J, Ivanenko M. A novel navigation principle in computer-assisted surgery. Conf Proc IEEE Eng Med Biol Soc 2007; 2004:3132-5. [PMID: 17270943 DOI: 10.1109/iembs.2004.1403884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Novel methods of laser measurements and interventions in the framework of image-guided surgery are presented. The first innovation concerns the basis of error propagation studies in registration chains from CT via OR navigator to the surgical laser tool holder. Here, we propose a holographic ground truth. The second innovation concerns a laser-based inherent sound-guidance principle for burr hole depth measurement.
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Affiliation(s)
- T M Buzug
- Department of Mathematics and Technology, RheinAhrCampus Remagen, Germany
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Rahimi A, Keilig L, Bendels G, Klein R, Buzug TM, Abdelgader I, Abboud M, Bourauel C. 3D Reconstruction of dental specimens from 2D histological images and μCT-Scans. Comput Methods Biomech Biomed Engin 2005; 8:167-76. [PMID: 16214711 DOI: 10.1080/10255840500296140] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Direct comparison of experimental and theoretical results in biomechanical studies requires a careful reconstruction of specimen surfaces to achieve a satisfactory congruence for validation. In this paper a semi-automatic approach is described to reconstruct triangular boundary representations from images originating from, either histological sections or microCT-, CT- or MRI-data, respectively. In a user-guided first step, planar 2D contours were extracted for every material of interest, using image segmentation techniques. In a second step, standard 2D triangulation algorithms were used to derive high quality mesh representations of the underlying surfaces. This was accomplished by converting the 2D meshes into 3D meshes by a novel lifting procedure. The meshes can be imported as is into finite element programme packages such as Marc/Mentat or COSMOS/M. Accuracy and feasibility of the algorithm is demonstrated by reconstructing several specimens as examples and comparing simulated results with available measurements performed on the original objects.
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Affiliation(s)
- A Rahimi
- University of Bonn, Department of Orthodontics, Welschnonnenstr.17, 53111, Bonn, Germany
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Rohr K, Stiehl HS, Sprengel R, Buzug TM, Weese J, Kuhn MH. Landmark-based elastic registration using approximating thin-plate splines. IEEE Trans Med Imaging 2001; 20:526-34. [PMID: 11437112 DOI: 10.1109/42.929618] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We consider elastic image registration based on a set of corresponding anatomical point landmarks and approximating thin-plate splines. This approach is an extension of the original interpolating thin-plate spline approach and allows to take into account landmark localization errors. The extension is important for clinical applications since landmark extraction is always prone to error. Our approach is based on a minimizing functional and can cope with isotropic as well as anisotropic landmark errors. In particular, in the latter case it is possible to include different types of landmarks, e.g., unique point landmarks as well as arbitrary edge points. Also, the scheme is general with respect to the image dimension and the order of smoothness of the underlying functional. Optimal affine transformations as well as interpolating thin-plate splines are special cases of this scheme. To localize landmarks we use a semi-automatic approach which is based on three-dimensional (3-D) differential operators. Experimental results are presented for two-dimensional as well as 3-D tomographic images of the human brain.
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Affiliation(s)
- K Rohr
- School of Information Technology, International University in Germany, Bruchsal.
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Abstract
A generalized framework for histogram-based similarity measures is presented and applied to the image-enhancement task in digital subtraction angiography (DSA). The class of differentiable, strictly convex weighting functions is identified as suitable weightings of histograms for measuring the degree of clustering that goes along with registration. With respect to computation time, the energy similarity measure is the function of choice for the registration of mask and contrast image prior to subtraction. The robustness of the energy measure is studied for geometrical image distortions like rotation and scaling. Additionally, it is investigated how the histogram binning and inhomogeneous motion inside the templates influence the quality of the similarity measure. Finally, the registration success for the automated procedure is compared with the manually shift-corrected image pair of the head.
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Affiliation(s)
- T M Buzug
- Philips Research Division, Technical Systems Hamburg, Germany.
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Weese J, Penney GP, Desmedt P, Buzug TM, Hill DL, Hawkes DJ. Voxel-based 2-D/3-D registration of fluoroscopy images and CT scans for image-guided surgery. IEEE Trans Inf Technol Biomed 1997; 1:284-93. [PMID: 11020832 DOI: 10.1109/4233.681173] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Registration of intraoperative fluoroscopy images with preoperative three-dimensional (3-D) CT images can be used for several purposes in image-guided surgery. On the one hand, it can be used to display the position of surgical instruments, which are being tracked by a localizer, in the preoperative CT scan. On the other hand, the registration result can be used to project preoperative planning information or important anatomical structures visible in the CT image onto the fluoroscopy image. For this registration task, a novel voxel-based method in combination with a new similarity measure (pattern intensity) has been developed. The basic concept of the method is explained at the example of two-dimensional (2-D)/3-D registration of a vertebra in an X-ray fluoroscopy image with a 3-D CT image. The registration method is described, and the results for a spine phantom are presented and discussed. Registration has been carried out repeatedly with different starting estimates to study the capture range. Information about registration accuracy has been obtained by comparing the registration results with a highly accurate "ground-truth" registration, which has been derived from fiducial markers attached to the phantom prior to imaging. In addition, registration results for different vertebrae have been compared. The results show that the rotation parameters and the shifts parallel to the projection plane can accurately be determined from a single projection. Because of the projection geometry, the accuracy of the height above the projection plane is significantly lower.
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Affiliation(s)
- J Weese
- Division of Radiological Sciences, Guy's Hospital, London, U.K.
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