Matching and reconstruction of brachytherapy seeds using the Hungarian algorithm (MARSHAL)

Ameet Kumar Jain, Yu Zhou, Tabish Mustufa, E. Clif Burdette, Gregory S. Chirikjian, Gabor Fichtinger

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


Purpose: Intraoperative dosimetric quality assurance in prostate brachytherapy critically depends on discerning the 3D locations of implanted seeds. The ability to reconstruct the implanted seeds intraoperatively will allow us to make immediate provisions for dosimetric deviations from the optimal implant plan. A method for seed reconstruction from segmented C-arm fluoroscopy images is proposed. Method: The 3D coordinates of the implanted seeds can be calculated upon resolving the correspondence of seeds in multiple X-ray images. We formalize seed-matching as a network flow problem, which has salient features: (a) extensively studied exact solutions, (b) performance claims on the space-time complexity, (c) optimality bounds on the final solution. A fast implementation is realized using the Hungarian algorithm. Results: We prove that two images can correctly match only about 67% of the seeds, and that a third image renders the matching problem to be of non-polynomial complexity. We utilize the special structure of the problem and propose a pseudo-polynomial time algorithm. Using three images, MARSHAL achieved 100% matching in simulation experiments; and 98.5% in phantom experiments. 3D reconstruction error for correctly matched seeds has a mean of 0.63 mm, and 0.91 mm for incorrectly matched seeds. Conclusion: Both on synthetic data and in phantom experiments, matching rate and reconstruction accuracy were found to be sufficient for prostate brachytherapy. The algorithm is extendable to deal with arbitrary number of images without loss in speed or accuracy. The algorithm is sufficiently generic to be used for establishing correspondences across any choice of features in different imaging modalities.

Original languageEnglish (US)
Title of host publicationProgress in Biomedical Optics and Imaging - Proceedings of SPIE
EditorsR.L. Galloway, Jr., K.R. Cleary
Number of pages12
StatePublished - 2005
EventMedical Imaging 2005 - Visualization, Image-Guided Procedures, and Display - San Diego, CA, United States
Duration: Feb 13 2005Feb 15 2005


OtherMedical Imaging 2005 - Visualization, Image-Guided Procedures, and Display
Country/TerritoryUnited States
CitySan Diego, CA


  • C-arm
  • Fluoroscopy
  • Prostate Brachytherapy
  • Radiation Planning
  • Reconstruction
  • Seed Matching

ASJC Scopus subject areas

  • Engineering(all)


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