A method to combine target volume data from 3D and 4D planned thoracic radiotherapy patient cohorts for machine learning applications

Corinne Johnson*, Gareth Price, Jonathan Khalifa, Corinne Faivre-Finn, Andre Dekker, Christopher Moore, Marcel van Herk

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Background and purpose: The gross tumour volume (GTV) is predictive of clinical outcome and consequently features in many machine-learned models. 4D-planning, however, has prompted substitution of the GTV with the internal gross target volume (iGTV). We present and validate a method to synthesise GTV data from the iGTV, allowing the combination of 3D and 4D planned patient cohorts for modelling. Material and methods: Expert delineations in 40 non-small cell lung cancer patients were used to develop linear fit and erosion methods to synthesise the GTV volume and shape. Quality was assessed using Dice Similarity Coefficients (DSC) and closest point measurements; by calculating dosimetric features; and by assessing the quality of random forest models built on patient populations with and without synthetic GTVs. Results: Volume estimates were within the magnitudes of inter-observer delineation variability. Shape comparisons produced mean DSCs of 0.8817 and 0.8584 for upper and lower lobe cases, respectively. A model trained on combined true and synthetic data performed significantly better than models trained on GTV alone, or combined GTV and iGTV data. Conclusions: Accurate synthesis of GTV size from the iGTV permits the combination of lung cancer patient cohorts, facilitating machine learning applications in thoracic radiotherapy. (C) 2017 Elsevier B.V. All rights reserved. Radiotherapy and Oncology 126 (2018) 355-361
Original languageEnglish
Pages (from-to)355-361
Number of pages7
JournalRadiotherapy and Oncology
Volume126
Issue number2
DOIs
Publication statusPublished - 1 Feb 2018

Keywords

  • Radiotherapy
  • Machine-learning
  • GTV
  • Lung cancer
  • GROSS TUMOR VOLUME
  • LUNG-CANCER PATIENTS
  • RADIATION PNEUMONITIS
  • EXTERNAL VALIDATION
  • DELINEATION
  • VARIABILITY
  • DEFINITION
  • SURVIVAL
  • MODEL

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