A novel rectal applicator for contact radiotherapy with HDR Ir-192 sources

Murillo Bellezzo, Gabriel P. Fonseca, An-Sofie Verrijssen, Robert Voncken, Michiel R. Van den Bosch, Helio Yoriyaz, Brigitte Reniers, Maaike Berbee, Evert J. Van Limbergen, Frank Verhaegen*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

PURPOSE: Dose escalation to rectal tumors leads to higher complete response rates and may thereby enable omission of surgery. Important advantages of endoluminal boosting techniques include the possibility to apply a more selective/localized boost than using external beam radiotherapy. A novel brachytherapy (BT) rectal applicator with lateral shielding was designed to be used with a rectoscope for eye-guided positioning to deliver a dose distribution similar to the one of contact x-ray radiotherapy devices, using commonly available high-dose-rate Ir-192 BT sources.

METHODS AND MATERIALS: A cylindrical multichannel BT applicator with lateral shielding was designed by Monte Carlo modeling, validated experimentally with film dosimetry and compared with results found in the literature for the Papillon 50 (P50) contact x-ray radiotherapy device regarding rectoscope dimensions, radiation beam shape, dose fall-off, and treatment time.

RESULTS: The multichannel applicator designed is able to deliver 30 Gy under 13 min with a 20350 U (5 Ci) source. The use of multiple channels and lateral shielding provide a uniform circular treatment surface with 22 mm in diameter. The resulting dose fall-off is slightly steeper (maximum difference of 5%) than the one generated by the P50 device with the 22 mm applicator.

CONCLUSIONS: A novel multichannel rectal applicator for contact radiotherapy with high-dose-rate Ir-192 sources that can be integrated with commercially available treatment planning systems was designed to produce a dose distribution similar to the one obtained by the P50 device. (C) 2018 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Original languageEnglish
Pages (from-to)1037-1044
Number of pages8
JournalBrachytherapy
Volume17
Issue number6
DOIs
Publication statusPublished - 2018

Keywords

  • Brachytherapy
  • Monte Carlo
  • Contact radiotherapy
  • Rectal applicator
  • X-RAY BRACHYTHERAPY
  • QUALITY-OF-LIFE
  • RADIATION-THERAPY
  • MONTE-CARLO
  • ORGAN PRESERVATION
  • TECHNICAL NOTE
  • CANCER
  • DOSIMETRY
  • ADENOCARCINOMA
  • PARAMETERS

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