Subpopulation-based correspondence modelling for improved respiratory motion estimation in the presence of inter-fraction motion variations

Matthias Wilms, René Werner, Tokihiro Yamamoto, Heinz Handels, Jan Ehrhardt

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Correspondence modelling between low-dimensional breathing signals and internal organ motion is a prerequisite for application of advanced techniques in radiotherapy of moving targets. Patient-specific correspondence models can, for example, be built prior to treatment based on a planning 4D CT and simultaneously acquired breathing signals. Reliability of pre-treatment-built models depends, however, on the degree of patient-specific inter-fraction motion variations. This study investigates whether motion estimation accuracy in the presence of inter-fraction motion variations can be improved using correspondence models that incorporate motion information from different patients. The underlying assumption is that inter-patient motion variations resemble patient-specific inter-fraction motion variations for subpopulations of patients with similar breathing characteristics. The hypothesis is tested by integrating a sparse manifold clustering approach into a regression-based correspondence modelling framework that allows for automated identification of patient subpopulations. The evaluation is based on a total of 73 lung 4D CT data sets, including two cohorts of patients with repeat 4D CT scans (cohort 1: 14 patients; cohort 2: ten patients). The results are consistent for both cohorts: The subpopulation-based modelling approach outperforms general population modelling (models built on all data sets available) as well as pre-treatment-built models trained on only the patient-specific motion information. The results thereby support the hypothesis and illustrate the potential of subpopulation-based correspondence modelling.

Original languageEnglish (US)
Pages (from-to)5823-5839
Number of pages17
JournalPhysics in Medicine and Biology
Volume62
Issue number14
DOIs
StatePublished - Jun 26 2017

Keywords

  • motion modeling
  • motion variability
  • radiation therapy
  • spectral clustering

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging

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