Deformable image registration for geometrical evaluation of DIBH radiotherapy treatment of lung cancer patients

17th International Conference on the Use of Computers in Radiation Therapy

物理学;计算机科学

Ottosson, W.^1,2 ; Lykkegaard Andersen, J.A.^2 ; Borrisova, S.^2 ; Mellemgaard, A.^2 ; Behrens, C.F.^2

Center for Nuclear Technologies, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark^1

Department of Oncology, Radiotherapy Research Unit, University of Copenhagen, DK-2730 Herlev, Denmark^2

关键词: Adaptive radiotherapy;    Anatomical structures;    Anatomical variations;    Deep inspiration breath hold;    Deformable image registration;    Locally advanced non-small-cell lung cancers;    Radiotherapy treatment;    Similarity coefficients;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/489/1/012077/pdf
DOI  :  10.1088/1742-6596/489/1/012077

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

Respiration and anatomical variation during radiotherapy (RT) of lung cancer yield dosimetric uncertainties of the delivered dose, possibly affecting the clinical outcome if not corrected for. Adaptive radiotherapy (ART), based on deformable image registration (DIR) and Deep-Inspiration-Breath-Hold (DIBH) gating can potentially improve the accuracy of RT. Purpose: The objective was to investigate the performance of contour propagation on repeated CT and Cone Beam CT (CBCT) images in DIBH compared to images acquired in free breathing (FB), using a recently released DIR software. Method: Three locally advanced non-small cell lung cancer patients were included, each with a planning-, midterm- and final CT (pCT, mCT, fCT) and 7 CBCTs acquired weekly and on the same day as the mCT and fCT. All imaging were performed in both FB and DIBH, using Varian RPM system for respiratory tracking. Delineations of anatomical structures were performed on each image set. The CT images were retrospective rigidly and deformable registered to all obtained images using the Varian Smart Adapt v. 11.0. The registered images were analysed for volume change and Dice Similarity Coefficient (DSC). Result: Geometrical similarities were found between propagated and manually delineated structures, with a slightly favour of FB imaging. Special notice should be taken to registrations where image artefacts or low tissue contrast are present. Conclusion: This study does not support the hypothesis that DIBH images perform better image registration than FB images. However DIR is a feasible tool for ART of lung cancer.