Intra-operative localization of brachytherapy implants using intensity-based registration

Z. KarimAghaloo, P. Abolmaesumi, N. Ahmidi, T. K. Chen, D. G. Gobbi, G. Fichtinger

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In prostate brachytherapy, a transrectal ultrasound (TRUS) will show the prostate boundary but not all the implanted seeds, while fluoroscopy will show all the seeds clearly but not the boundary. We propose an intensitybased registration between TRUS images and the implant reconstructed from fluoroscopy as a means of achieving accurate intra-operative dosimetry. The TRUS images are first filtered and compounded, and then registered to the fluoroscopy model via mutual information. A training phantom was implanted with 48 seeds and imaged. Various ultrasound filtering techniques were analyzed, and the best results were achieved with the Bayesian combination of adaptive thresholding, phase congruency, and compensation for the non-uniform ultrasound beam profile in the elevation and lateral directions. The average registration error between corresponding seeds relative to the ground truth was 0.78 mm. The effect of false positives and false negatives in ultrasound were investigated by masking true seeds in the fluoroscopy volume or adding false seeds. The registration error remained below 1.01 mm when the false positive rate was 31%, and 0.96 mm when the false negative rate was 31%. This fully automated method delivers excellent registration accuracy and robustness in phantom studies, and promises to demonstrate clinically adequate performance on human data as well.

Original languageEnglish (US)
Title of host publicationProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume7261
DOIs
StatePublished - 2009
Externally publishedYes
EventMedical Imaging 2009: Biomedical Applications in Molecular, Structural, and Functional Imaging - Lake Buena Vista, FL, United States
Duration: Feb 8 2009Feb 10 2009

Other

OtherMedical Imaging 2009: Biomedical Applications in Molecular, Structural, and Functional Imaging
Country/TerritoryUnited States
CityLake Buena Vista, FL
Period2/8/092/10/09

Keywords

  • Fluoroscopy
  • Prostate brachytherapy
  • Registration.
  • Ultrasound

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

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