Abstract
The use of image-guidance in surgery and radiotherapy has significantly improved
patient outcome in neurosurgery and radiotherapy treatments. This work developed
volume definition and verification techniques for image-guided applications,
using a number of algorithms ranging from image processing to visualization.
Stereoscopic visualization, volumetric tumor model overlaid on an ultrasound
image, and visualization of the treatment geometry were experimented with on a
neurosurgical workstation. Visualization and volume definition tools were
developed for radiotherapy treatment planning system.
The magnetic resonance inhomogeneity correction developed in this work, possibly
the first published data-driven method with wide applicability, automatically
mitigates the RF field inhomogeneity artefact present in magnetic resonance
images. Correcting the RF inhomogeneity improves the accuracy of the generated
volumetric models.
Various techniques to improve region growing are also presented. The simplex
search method and combinatory similarity terms were used to improve the
similarity function with a low additional computational cost and high yield in
region correctness. Moreover, the effects of different priority queue
implementations were studied.
A fast algorithm for calculating high-quality digitally reconstructed radiographs
has been developed and shown to better meet typical radiotherapy needs than the
two alternative algorithms. A novel visualization method, beam's light view, is
presented. It uses texture mapping for projecting the fluence of a radiation
field on an arbitrary surface.
This work suggests several improved algorithms for image processing,
segmentation, and visualization used in image-guided treatment systems. The
presented algorithms increase the accuracy of image-guidance, which can further
improve the applicability and efficiency of image-guided treatments.
| Identifer | oai:union.ndltd.org:oulo.fi/oai:oulu.fi:isbn951-42-6574-2 |
| Date | 19 November 2001 |
| Creators | Alakuijala, J. (Jyrki) |
| Publisher | University of Oulu |
| Source Sets | University of Oulu |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:eu-repo/semantics/publishedVersion |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess, © University of Oulu, 2001 |
| Relation | info:eu-repo/semantics/altIdentifier/pissn/0355-3213, info:eu-repo/semantics/altIdentifier/eissn/1796-2226 |
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