Dose reconstruction technique using non-rigid registration to evaluate spatial correspondence between high-dose region and late radiation toxicity: A case of tracheobronchial stenosis after external beam radiotherapy combined with endotracheal brachytherapy for tracheal cancer

Kazuma Kobayashi, Naoya Murakami, Koji Inaba, Akihisa Wakita, Satoshi Nakamura, Hiroyuki Okamoto, Jun Sato, Rei Umezawa, Kana Takahashi, Hiroshi Igaki, Yoshinori Ito, Naoyuki Shigematsu, Jun Itami

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Purpose: Small organ subvolume irradiated by a high-dose has been emphasized to be associated with late complication after radiotherapy. Here, we demonstrate a potential use of surface-based, non-rigid registration to investigate how high-dose volume topographically correlates with the location of late radiation morbidity in a case of tracheobronchial radiation stenosis. Material and methods: An algorithm of point set registration was implemented to handle non-rigid registration between contour points on the organ surfaces. The framework estimated the global correspondence between the dose distribution and the varying anatomical structure. We applied it to an 80-year-old man who developed tracheobronchial stenosis 2 years after high-dose-rate endobronchial brachytherapy (HDR-EBT) (24 Gy in 6 Gy fractions) and external beam radiotherapy (EBRT) (40 Gy in 2 Gy fractions) for early-stage tracheal cancer. Results and conclusions: Based on the transformation function computed by the non-rigid registration, irradiated dose distribution was reconstructed on the surface of post-treatment tracheobronchial stenosis. For expressing the equivalent dose in a fractional dose of 2 Gy in HDR-EBT, α/β of linear quadratic model was assumed as 3 Gy for the tracheal bronchus. The tracheobronchial surface irradiated by more than 100 Gyαβ3 tended to develop severe stenosis, which attributed to a more than 50% decrease in the luminal area. The proposed dose reconstruction technique can be a powerful tool to predict late radiation toxicity with spatial consideration.

Original languageEnglish
Pages (from-to)156-163
Number of pages8
JournalJournal of Contemporary Brachytherapy
Volume8
Issue number2
DOIs
Publication statusPublished - 2016
Externally publishedYes

Keywords

  • Image registration
  • Radiation toxicity
  • Tracheal cancer

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging

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