Deformable registration of X-ray to MRI for post-implant dosimetry in prostate brachytherapy

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

Abstract

Post-implant dosimetric assessment in prostate brachytherapy is typically performed using CT as the standard imaging modality. However, poor soft tissue contrast in CT causes significant variability in target contouring, resulting in incorrect dose calculations for organs of interest. CT-MR fusion-based approach has been advocated taking advantage of the complementary capabilities of CT (seed identification) and MRI (soft tissue visibility), and has proved to provide more accurate dosimetry calculations. However, seed segmentation in CT requires manual review, and the accuracy is limited by the reconstructed voxel resolution. In addition, CT deposits considerable amount of radiation to the patient. In this paper, we propose an X-ray and MRI based post-implant dosimetry approach. Implanted seeds are localized using three X-ray images by solving a combinatorial optimization problem, and the identified seeds are registered to MR images by an intensity-based points-to-volume registration. We pre-process the MR images using geometric and Gaussian filtering. To accommodate potential soft tissue deformation, our registration is performed in two steps, an initial affine transformation and local deformable registration. An evolutionary optimizer in conjunction with a points-to-volume similarity metric is used for the affine registration. Local prostate deformation and seed migration are then adjusted by the deformable registration step with external and internal force constraints. We tested our algorithm on six patient data sets, achieving registration error of (1.2±0.8) mm in < 30 sec. Our proposed approach has the potential to be a fast and cost-effective solution for post-implant dosimetry with equivalent accuracy as the CT-MR fusion-based approach.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling
PublisherSPIE
Volume9786
ISBN (Electronic)9781510600218
DOIs
StatePublished - 2016
EventMedical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling - San Diego, United States
Duration: Feb 28 2016Mar 1 2016

Other

OtherMedical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling
CountryUnited States
CitySan Diego
Period2/28/163/1/16

Fingerprint

Brachytherapy
Magnetic resonance imaging
Dosimetry
dosimeters
Seed
seeds
Prostate
Seeds
X-Rays
X rays
Tissue
x rays
Fusion reactions
fusion
Combinatorial optimization
visibility
Visibility
organs
Deposits
deposits

Keywords

  • deformable registration
  • Post-implant dosimetry
  • prostate brachytherapy
  • X-ray to MRI registration

ASJC Scopus subject areas

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

Cite this

Park, S., Song, D. Y., & Lee, J. (2016). Deformable registration of X-ray to MRI for post-implant dosimetry in prostate brachytherapy. In Medical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling (Vol. 9786). [97860L] SPIE. https://doi.org/10.1117/12.2216911

Deformable registration of X-ray to MRI for post-implant dosimetry in prostate brachytherapy. / Park, Seyoun; Song, Danny Y; Lee, Junghoon.

Medical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling. Vol. 9786 SPIE, 2016. 97860L.

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

Park, S, Song, DY & Lee, J 2016, Deformable registration of X-ray to MRI for post-implant dosimetry in prostate brachytherapy. in Medical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling. vol. 9786, 97860L, SPIE, Medical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling, San Diego, United States, 2/28/16. https://doi.org/10.1117/12.2216911
Park S, Song DY, Lee J. Deformable registration of X-ray to MRI for post-implant dosimetry in prostate brachytherapy. In Medical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling. Vol. 9786. SPIE. 2016. 97860L https://doi.org/10.1117/12.2216911
Park, Seyoun ; Song, Danny Y ; Lee, Junghoon. / Deformable registration of X-ray to MRI for post-implant dosimetry in prostate brachytherapy. Medical Imaging 2016: Image-Guided Procedures, Robotic Interventions, and Modeling. Vol. 9786 SPIE, 2016.
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