Dynamic intraoperative dosimetry for prostate brachytherapy using a nonisocentric C-arm

Danny Y. Song, Ameet K. Jain, Zhe Zhang, Anton Deguet, Yi Le, Elwood Armour, E. Clif Burdette, Gabor Fichtinger

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: To evaluate a prototypical system of dynamic intraoperative dosimetry for prostate brachytherapy using registered ultrasound and fluoroscopy (RUF) with a nonisocentric C-arm (GE OEC, Salt Lake City, UT) and to compare intraoperative dosimetry of RUF as well as ultrasound-based seed localization (USD) with Day 0 CT dosimetry. Methods: Seed positions were independently determined using RUF and USD. RUF uses a radio-opaque fiducial for registration to ultrasound and 3-dimensional reconstruction of seeds relative to prostate using nonisocentric C-arm fluoroscopy. Postimplant CT was performed on Day 0. Squared differences between dosimetric measures for RUF vs. CT and USD vs. CT were calculated and mean squared differences evaluated. Paired t test was used to evaluate which method was more closely aligned with CT. Accuracies of USD and RUF compared with CT were estimated using a nonparametric approach. Results: Six patients were treated and compared with USD. RUF identified areas of underdosage intraoperatively in all patients and median 5 additional seeds were placed. In 40 of 42 measures, RUF was equally or more closely correlated with CT than USD. USD showed statistically significant variation from CT for 6 of 7 parameters compared with 1 of 7 parameters for RUF. Mean squared differences from CT were significantly smaller for RUF in 4 of 7 parameters compared with USD. Conclusions: Dynamic intraoperative dosimetry is possible with a conventional nonisocentric C-arm. Compared with an USD method, RUF-based intraoperative dosimetry was more closely aligned with immediate postimplant CT. RUF identified areas of underdosage, which were not detected using USD.

Original languageEnglish (US)
Pages (from-to)98-106
Number of pages9
JournalBrachytherapy
Volume10
Issue number2
DOIs
StatePublished - Mar 2011

Keywords

  • C-arm
  • Dynamic dosimetry
  • Intraoperative
  • Prostate brachytherapy
  • Real-time dosimetry

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging

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