Picture Dipl.-Ing. Stefan Suwelack

Phone: +49 (0)721 608 48488
Fax: +49 (0)721 608 48270
E-Mail: suwelack(at)kit(dot)edu

Address
Karlsruhe Institute of Technology
Institute for Anthropomatics
Adenauerring 2, D-76131 Karlsruhe
Building 50.20, 3rd Floor, Room 324

Research Interests

There is no harm in doubt and skepticism, for it is through these that new discoveries are made
Richard Feynman

Computer assisted navigation for laparoscopic soft tissue interventions

In the context of minimally invasive interventions, computer assisted surgery (CAS) systems are a key technology for improving patient outcomes. In a similar fashion as automotive navigation systems can give directions to the driver, CAS systems can provide guidance to the surgeon during an intervention. In order to display accurate navigational information, preoperative planning data (“the roadmap”) has to be registered to the patient. For many interventions this is a challenging task due to the significant soft tissue deformations that occur during surgery.

We are developing a new approach that seeks to track soft tissue movements from sparse intraoperative sensor data (e.g. endoscopes, ultrasound) by using a-priori information about the tissue’s mechanical properties.

  3D surface reconstructed from endoscopic images
FE model of the liver deformed under respiration
Liver resection modeled by X-FEM
Real-time soft tissue simulation

Elasticity theory can be used to describe the mechanical behavior of soft tissue using partial differential equations (PDE). The PDE can be subsequently solved using the finite element method (FEM). In order to use a FE model for soft tissue registration, it does not only have to be very accurate, but it also has to run in real-time. Furthermore the model must be able to accommodate topological changes (i.e. surgical cuts).

In order to meet these demands we are investigating new numerical methods based on the Discontinuous Galerking FEM and the Extended FEM. Our approach allows for flexible constraint handling and provides an effective way to model discontinuities in the solution.

 

Teaching

To teach is to learn twice
Joseph Joubert

I enjoy teaching and consider it to be not only a very important, but also a very rewarding part of my work.

  • Lecture

    Together with my colleague Roland Unterhinninghofen I teach Medical Simulation Systems 2. The lecture introduces the most important numerical methods that are used in medical simulation. We cover both problems from solid mechanics (surgery simulation, soft tissue registration) and fluid dynamics (hemodynamics). The goal of the lecture is to convey a fundamental understanding for the potential and the limitations of medical simulation techniques.

  • Seminars

    Our group runs a seminar every semester for undergraduate and postgraduate students. The seminar covers current research topics in the context of medical image processing, computer assisted surgery and medical simulation. More information can be found here (winter semester) and here (summer semester). If you would like to participate and are interested in soft tissue simulation or intraoperative soft tissue registration, please feel free to write me an e-mail.

    We also host the seminar “Intelligent Surgery” for all student members of our group. We meet approx. twice per month to present and discuss current thesis work. If you are interested in joining our group for your Bachelor or Master thesis, you are cordially invited to participate. Just drop me an e-mail and I’ll put you on the mailing list.

  • Popular Science

    I like to share my enthusiasm for my research work with non-scientists. Recently, my colleague Yoo-Jin Jeong and I prepared an introductory lecture about radiology for children in the framework of the KIT Kinderuni. Check out the slides (in German) or the short video summary (also in German). Can you guess what’s in the lunch box?

Open Thesis Topics

                                 Nothing is more powerful than an idea whose time has come
Victor Hugo

You can find current open thesis topics in the paragraph below. More thesis topics that are supervised by my colleagues can be found here. Please note that I often fail to keep the following list updated. Also, I always try to tailor the thesis topics to my student’s research interests and skills. So please send me an email if you are interested in doing thesis work in the context of soft tissue simulation or intraoperative soft tissue registration. We can then find the perfect topic for you.

 

Publications

                                


2012

S. Röhl, S. Bodenstedt, S. Suwelack, R. Dillmann, H. Kenngott, BP Müller-Stich and S. Speidel Dense gpu-enhanced surface reconstruction from stereo endoscopic images for intraoperative registration
Medical Physics
, 2012
S. Suwelack, D. Katic, S. Wagner, P. Spengler, S. Bodenstedt, S. Röhl, R. Dillmann and S. Speidel Lightweight distributed computing for intraoperative real-time image guidance
SPIE Medical Imaging
, 2012
S. Röhl, S. Bodenstedt, C. Küderle, S. Suwelack, H. Kenngott, BP Müller-Stich, R. Dillmann and S. Speidel Fusion of intraoperative force sensoring, surface reconstruction and biomechanical modeling
SPIE Medical Imaging
, 2012
2011
S. Suwelack, S. Roehl, R. Dillmann, A. Wekerle, H. Kenngott, B. Müller-Stich, C. Alt and S. Speidel. Quadratic corotated finite elements for real-time soft tissue registration
MICCAI workshop: Computational Biomechanics for Medicine
, 2011
S. Speidel, S. Roehl, S. Suwelack, R. Dillmann, H. Kenngott and B. Mueller-Stich Intraoperative surface reconstruction and biomechanical modeling for soft tissue registration
Joint Workshop on New Technologies for Computer/Robot Assisted Surgery
, 2011
S. Suwelack, S. Roehl, R. Dillmann and S. Speidel A biomechanical liver model for intraoperative soft tissue registration
SPIE Medical Imaging, 2011
S. Suwelack, S. Maier, R. Unterhinninghofen, and R. Dillmann Web-based volume rendering
Medicine Meets Virtual Reality (MMVR), 2011
S. Roehl, S. Bodenstedt, S. Suwelack, H. Kenngott, B.P. Mueller-Stich, R. Dillmann, and S. Speidel Real-time surface reconstruction from stereo endoscopic images for intraoperative registration
SPIE Medical Imaging, 2011
S. Bodenstedt, S. Roehl, S. Suwelack, D. Katic, R. Dillmann, B. Müller-Stich, and S. Speidel A flexible framework for multiple sensor integration into a context-aware cas-system
Computer Assisted Radiology and Surgery (CARS), 2011.
2010
S. Suwelack, E. Heitz, R. Unterhinninghofen, and R. Dillmann Adaptive gpu ray casting based on spectral analysis
Medical Imaging and Augmented Reality (MIAR), 2010.
S. Suwelack, S. Speidel, S. Roehl, and R. Dillmann Towards finite element-based soft tissue modeling for real-time image registration
Computer Assisted Radiology and Surgery (CARS), 2010.
B. Pfau, S. Suwelack, R. Dillmann, and V. Heuveline Soft tissue simulation using discontinuous galerkin fem
RICAM Workshop on Discontinuous Galerkin Methods, 2010.