Source position measurement by Cherenkov emission imaging from applicators for high-dose-rate brachytherapy

Katsunori Yogo*, Yumiko Noguchi, Kuniyasu Okudaira, Marika Nozawa, Hiromichi Ishiyama, Hiroyuki Okamoto, Hiroshi Yasuda, Hiroshi Oguchi, Seiichi Yamamoto

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Purpose: We developed a novel and simple method to measure the source positions in applicators directly for high-dose-rate (HDR) brachytherapy based on Cherenkov emission imaging, and evaluated the performance. Methods: The light emission from plastic applicators used in cervical cancer treatments, irradiated by an 192Ir γ-ray source, was captured using a charge-coupled device camera. Moreover, we attached plastics of different shapes, including tapes, tubes, and plates to a metal applicator, to use as screens for the Cherenkov imaging. We determined the source positions and dwell intervals from the light profiles along with the applicator and compared these with preset values and dummy marker measurements. Results: The source positions and dwell intervals measured from the light images were comparable to the dummy marker measurements and preset values. The distance from the applicator tip to the first source positions agreed with the dummy marker measurements within 0.2 mm for the plastic tandem. The dwell intervals measured using the Cherenkov method agreed with the preset values within 0.6 mm. The distances measured with three plastic types on the metal applicator also agreed with the dummy marker measurements within 0.2 mm. The dwell intervals measured using the plastic tape agreed with the preset values within 0.7 mm. Conclusions: The proposed method should be suitable for rapid and easy quality assurance (QA) investigations in HDR brachytherapy, as it enables source position using a single image. The method allows for real-time, filmless measurements of the source positions to be obtained and is useful for rapid feedback in QA procedures.

Original languageEnglish
Pages (from-to)488-499
Number of pages12
JournalMedical Physics
Volume48
Issue number1
DOIs
Publication statusPublished - 2021 Jan
Externally publishedYes

Keywords

  • applicator
  • Cherenkov emission
  • high-dose-rate brachytherapy
  • quality assurance
  • source position measurement

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

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