Three-dimensional dosimetry of TomoTherapy by MRI-based polymer gel technique

Yoichi Watanabe, N. Gopishankar

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Verification of the dose calculation model and the software used for treatment planning is an important step for accurate radiation delivery in radiation therapy. Using BANG3 polymer gel dosimeter with a 3 Tesla magnetic resonance imaging (MRI) scanner, we examined the accuracy of TomoTherapy treatment planning and radiation delivery. We evaluated one prostate treatment case and found the calculated three-dimensional (3D) dose distributions agree with the measured 3D dose distributions with an exception in the regions where the dose was much smaller (25% or less) than the maximum dose (2.5 Gy). The analysis using the gamma-index (3% dose difference and 3 mm distance-to-agreement) for a volume of 12 cm × 11 cm × 9 cm containing the planning target volume showed that the gamma values were smaller than unity for 53% of the voxels. Our measurement protocol and analysis tools can be easily applied to the evaluation of other newer complex radiation delivery techniques, such as intensity-modulated arc therapy, with a reasonably low financial investment.

Original languageEnglish (US)
Pages (from-to)14-27
Number of pages14
JournalJournal of Applied Clinical Medical Physics
Volume12
Issue number1
DOIs
StatePublished - 2011

Keywords

  • 3D dose measurement
  • Helical TomoTherapy
  • IMRT
  • Polymer gel

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