Project heads:
Hon.-Prof. Hans-Christian Hege
/
Dr. Martin Weiser
/
Dr.-Ing. Stefan Zachow
Project members:
Dennis Jentsch
Duration: -
Status:
completed
Located at:
Konrad-Zuse-Zentrum für Informationstechnik Berlin
Description
Medical imaging is essential in diagnostics and surgery planning.
For representation of bony structures different imaging modalities
are used; the leading methods are X-ray projection (projectional
radiography) and CT. Disadvantage of these imaging techniques is
the ionization caused by X-rays, particularly in CT, where the dose
is 250-500 times higher than in classic X-ray projection. From the
clinical perspective therefore one would like to replace CT
acquisitions by a few possible X-ray projections.
The project deals with the ill-posed inverse problem of 3D
reconstruction of bony structures from 2D radiographs. Virtual
radiographs are generated from virtual bone structure models; these
are compared with clinical patient images and incrementally changed
until a sufficiently accurate bone model is found whose virtual
projections fit to the measured data.
By using a statistical shape model as prior knowledge it is
possible to formulate a well-posed optimization problem in a
Bayesian setting. Using gradient methods and
multilevel/multiresolution methods for both the reconstruction
parameters and image data, good computational performance is
achieved.
Uncertainty quantification techniques can be applied to describe
the spatially varying accuracy of the reconstructed model. Finding
best X-ray projections (recording directions) minimizing both
uncertainty and radiation exposure leads to a design of
experiments problem. Two flavors of this design optimization are
considered: An all-at-once approach finding the best image
acquisition setup before any X-ray projections are performed, and a
sequential approach determining the best next projection direction
based on the accumulated knowledge gained from the previously taken
images.
http://www.zib.de/projects/x-ray-based-anatomy-reconstruction-low-radiation-exposure
