Background and purpose: Devices that combine an MR-scanner with a Linac for radiotherapy, referred to as MR-Linac systems, introduce the possibility to acquire high resolution images prior and during treatment. Hence, there is a possibility to acquire individualised learning sets for motion models for each fraction and the construction of intrafractional motion models. We investigated the feasibility for a principal component analysis (PCA) based, intrafractional motion model of the male pelvic region. Materials and methods: 4D-scans of nine healthy male volunteers were utilized, FOV covering the entire pelvic region including prostate, bladder and rectum with manual segmentation of each organ at each time frame. Deformable image registration with an optical flow algorithm was performed for each subject with the first time frame as reference. PCA was performed on a subset of the resulting displacement vector fields to construct individualised motion models evaluated on the remaining fields. Results: The registration algorithm produced accurate registration result, in general DICE overlap >0.95 across all time frames. Cumulative variance of the eigen values from the PCA showed that 50% or more of the motion is explained in the first component for all subjects. However, the size and direction for the components differed between subjects. Adding more than two components did not improve the accuracy significantly and the model was able to explain motion down to about 1 mm. onclusions: An individualised intrafractional male pelvic motion model is feasible. Geometric accuracy was about 1 mm based on 1-2 principal components.


    Zugriff

    Download


    Exportieren, teilen und zitieren



    Titel :

    Intrafractional motion models based on principal components in Magnetic Resonance guided prostate radiotherapy


    Beteiligte:
    Fransson, Samuel (Autor:in) / Tilly, David (Autor:in) / Ahnesjö, Anders (Autor:in) / Nyholm, Tufve (Autor:in) / Strand, Robin (Autor:in)

    Erscheinungsdatum :

    2021-01-01


    Anmerkungen:

    Scopus 2-s2.0-85122824858



    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch



    Klassifikation :

    DDC:    629



    Intrafractional motion models based on principal components in Magnetic Resonance guided prostate radiotherapy

    Fransson, Samuel / Tilly, David / Ahnesjö, Anders et al. | BASE | 2021

    Freier Zugriff

    Real-time intrafraction prostate motion during linac based stereotactic radiotherapy with rectal displacement

    Legge, Kimberley / Nguyen, Doan / Ng, Jin Aun et al. | BASE | 2017

    Freier Zugriff


    Single-fraction prostate stereotactic body radiotherapy: Dose reconstruction with electromagnetic intrafraction motion tracking

    Jaccard, Maud / Ehrbar, Stefanie / Miralbell, Raymond et al. | BASE | 2021

    Freier Zugriff