Affordable Access

deepdyve-link
Publisher Website

Auto-masked 2D/3D image registration and its validation with clinical cone-beam computed tomography.

Authors
  • Steininger, P
  • Neuner, M
  • Weichenberger, H
  • Sharp, G C
  • Winey, B
  • Kametriser, G
  • Sedlmayer, F
  • Deutschmann, H
Type
Published Article
Journal
Physics in Medicine and Biology
Publisher
IOP Publishing
Publication Date
Jul 07, 2012
Volume
57
Issue
13
Pages
4277–4292
Identifiers
DOI: 10.1088/0031-9155/57/13/4277
PMID: 22705709
Source
Medline
License
Unknown

Abstract

Image-guided alignment procedures in radiotherapy aim at minimizing discrepancies between the planned and the real patient setup. For that purpose, we developed a 2D/3D approach which rigidly registers a computed tomography (CT) with two x-rays by maximizing the agreement in pixel intensity between the x-rays and the corresponding reconstructed radiographs from the CT. Moreover, the algorithm selects regions of interest (masks) in the x-rays based on 3D segmentations from the pre-planning stage. For validation, orthogonal x-ray pairs from different viewing directions of 80 pelvic cone-beam CT (CBCT) raw data sets were used. The 2D/3D results were compared to corresponding standard 3D/3D CBCT-to-CT alignments. Outcome over 8400 2D/3D experiments showed that parametric errors in root mean square were <0.18° (rotations) and <0.73 mm (translations), respectively, using rank correlation as intensity metric. This corresponds to a mean target registration error, related to the voxels of the lesser pelvis, of <2 mm in 94.1% of the cases. From the results we conclude that 2D/3D registration based on sequentially acquired orthogonal x-rays of the pelvis is a viable alternative to CBCT-based approaches if rigid alignment on bony anatomy is sufficient, no volumetric intra-interventional data set is required and the expected error range fits the individual treatment prescription.

Report this publication

Statistics

Seen <100 times