Automated intraoperative calibration for prostate cancer brachytherapy

Thomas Kuiran Chen, Tamas Heffter, Andras Lasso, Csaba Pinter, Purang Abolmaesumi, E. Clif Burdette, Gabor Fichtinger

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: Prostate cancer brachytherapy relies on an accurate spatial registration between the implant needles and the TRUS image, called calibration. The authors propose a new device and a fast, automatic method to calibrate the brachytherapy system in the operating room, with instant error feedback. Methods: A device was CAD-designed and precision-engineered, which mechanically couples a calibration phantom with an exact replica of the standard brachytherapy template. From real-time TRUS images acquired from the calibration device and processed by the calibration system, the coordinate transformation between the brachytherapy template and the TRUS images was computed automatically. The system instantly generated a report of the target reconstruction accuracy based on the current calibration outcome. Results: Four types of validation tests were conducted. First, 50 independent, real-time calibration trials yielded an average of 0.57 ± 0.13 mm line reconstruction error (LRE) relative to ground truth. Second, the averaged LRE was 0.37 ± 0.25 mm relative to ground truth in tests with six different commercial TRUS scanners operating at similar imaging settings. Furthermore, testing with five different commercial stepper systems yielded an average of 0.29 ± 0.16 mm LRE relative to ground truth. Finally, the system achieved an average of 0.56 ± 0.27 mm target registration error (TRE) relative to ground truth in needle insertion tests through the template in a water tank. Conclusions: The proposed automatic, intraoperative calibration system for prostate cancer brachytherapy has achieved high accuracy, precision, and robustness.

Original languageEnglish (US)
Pages (from-to)6285-6299
Number of pages15
JournalMedical Physics
Volume38
Issue number11
DOIs
StatePublished - Nov 2011

Keywords

  • brachytherapy
  • intraoperative ultrasound calibration
  • prostate cancer
  • TRUS

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging

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