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Proceedings Paper

Reconstruction of 4D-CT data sets acquired during free breathing for the analysis of respiratory motion
Author(s): Jan Ehrhardt; Rene Werner; Thorsten Frenzel; Dennis Säring; Wei Lu; Daniel Low; Heinz Handels
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Paper Abstract

Respiratory motion is a significant source of error in radiotherapy treatment planning. 4D-CT data sets can be useful to measure the impact of organ motion caused by breathing. But modern CT scanners can only scan a limited region of the body simultaneously and patients have to be scanned in segments consisting of multiple slices. For studying free breathing motion multislice CT scans can be collected simultaneously with digital spirometry over several breathing cycles. The 4D data set is assembled by sorting the free breathing multislice CT scans according to the couch position and the tidal volume. But artifacts can occur because there are no data segments for exactly the same tidal volume and all couch positions. We present an optical flow based method for the reconstruction of 4D-CT data sets from multislice CT scans, which are collected simultaneously with digital spirometry. The optical flow between the scans is estimated by a non-linear registration method. The calculated velocity field is used to reconstruct a 4D-CT data set by interpolating data at user-defined tidal volumes. By this technique, artifacts can be reduced significantly. The reconstructed 4D-CT data sets are used for studying inner organ motion during the respiratory cycle. The procedures described were applied to reconstruct 4D-CT data sets for four tumour patients who have been scanned during free breathing. The reconstructed 4D data sets were used to quantify organ displacements and to visualize the abdominothoracic organ motion.

Paper Details

Date Published: 10 March 2006
PDF: 8 pages
Proc. SPIE 6144, Medical Imaging 2006: Image Processing, 614414 (10 March 2006); doi: 10.1117/12.651730
Show Author Affiliations
Jan Ehrhardt, Univ. Medical Ctr. Hamburg-Eppendorf (Germany)
Rene Werner, Univ. Medical Ctr. Hamburg-Eppendorf (Germany)
Thorsten Frenzel, Hermann Holthusen Institute of Radiotherapy (Germany)
Dennis Säring, Univ. Medical Ctr. Hamburg-Eppendorf (Germany)
Wei Lu, Washington Univ. School of Medicine, St. Louis (United States)
Daniel Low, Washington Univ. School of Medicine, St. Louis (United States)
Heinz Handels, Univ. Medical Ctr. Hamburg-Eppendorf (Germany)

Published in SPIE Proceedings Vol. 6144:
Medical Imaging 2006: Image Processing
Joseph M. Reinhardt; Josien P. W. Pluim, Editor(s)

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