Dose coverage calculation using a statistical shape model - applied to cervical cancer radiotherapy
2016 (English)In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560Article in journal (Refereed) Accepted
A comprehensive treatment simulation framework is created where a patient geometry sampler built from a population based statistical shape model (SSM) provides efficient sampling of the deformation at every fraction to create a treatment planning tool for evaluating the dose coverage probabilities.
Deformable image registration from repeat imaging extracts the intra-patient deformations which are mapped to an average patient serving as a common frame of reference. The SSM is created by extracting the dominating eigenmodes by principal component analysis of the deformations from all patients in the training set. The sampling of a deformation is reduced to sampling of the eigenmode weights from their respective probability distribution defined by the eigenvalues. The framework is applied to five inoperable cervix cancer patients. The images as well as manually drawn contours are used in the registration to handle the large inter-fraction deformations.
Fifteen eigenmodes were needed to capture 90% of the variance in the deformation and seven eigenmodes to reach stability in the simulated dose coverage probabilities. The created probabilistic evaluation tool provided more information regarding the trade-off between target dose coverage and organ at risk sparing than the original planning based on a single image series.
Place, publisher, year, edition, pages
Radiotherapy, probabilistic, statistical shape model, principal component analysis, deformable image registration, cervix
Other Medical Engineering
Research subject Medical Radiophysics
IdentifiersURN: urn:nbn:se:uu:diva-304979OAI: oai:DiVA.org:uu-304979DiVA: diva2:1034212