Purpose: The accuracy of 4D-CT registration is limited by inconsistent Hounsfield unit (HU) values in the 4D-CT data from one respiratory phase to another and lower image contrast for lung substructures. This paper presents an optical flow and thin-plate spline (TPS)-based 4D-CT registration method to account for these limitations.
Methods: The use of unified HU values on multiple anatomy levels (e.g., the lung contour, blood vessels, and parenchyma) accounts for registration errors by inconsistent landmark HU value. While 3D multi-resolution optical flow analysis registers each anatomical level, TPS is employed for propagating the results from one anatomical level to another ultimately leading to the 4D-CT registration. 4D-CT registration was validated using target registration error (TRE), inverse consistency error (ICE) metrics, and a statistical image comparison using Gamma criteria of 1 % intensity difference in 2 mm(3) window range.
Results: Validation results showed that the proposed method was able to register CT lung datasets with TRE and ICE values <3 mm. In addition, the average number of voxel that failed the Gamma criteria was <3 %, which supports the clinical applicability of the propose registration mechanism.
Conclusion: The proposed 4D-CT registration computes the volumetric lung deformations within clinically viable accuracy.
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http://dx.doi.org/10.1007/s11548-013-0975-7 | DOI Listing |
Pract Radiat Oncol
December 2024
Department of Radiation Oncology, Willis Knighton Cancer Center, 2600 Kings Highway, Shreveport, Louisiana, USA 71103 &, Department of Clinical Research, University of Jamestown, Fargo, ND, USA. Electronic address:
Purpose: Motion management presents a significant challenge in thoracic stereotactic ablative radiotherapy (SABR). Currently, a 5.0 mm standard planning target volume (PTV) margin is widely used to ensure adequate dose to the tumor.
View Article and Find Full Text PDFTech Innov Patient Support Radiat Oncol
December 2024
Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, USA.
Purpose: We evaluated and benchmarked a novel deformable image registration (DIR) software functionality (DirOne, Cosylab d.d., Ljubljana, Slovenia) by comparing it to two commercial systems, MIM and VelocityAI, following AAPM task group 132 (TG-132) guidelines.
View Article and Find Full Text PDFQuant Imaging Med Surg
December 2024
Anhui Province Key Laboratory of Medical Physics and Technology, Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Hefei Cancer Hospital, Chinese Academy of Sciences, Hefei, China.
Cureus
November 2024
Department of Radiation Oncology, Hiroshima High-Precision Radiotherapy Cancer Center, Hiroshima, JPN.
Purpose We developed a volumetric quantitative evaluation software called vector volume histogram (VVH) to evaluate respiratory-induced organ motion using deformable image registration (DIR). Methods The B-spline-based DIR algorithm was used to compute the deformation vector field (DVF), which included the DVF (left-right), DVF (anterior-posterior), and DVF (craniocaudal). The VVH software was written as a plug-in using Python, thus allowing anyone to easily modify the code.
View Article and Find Full Text PDFMed Phys
December 2024
Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, California, USA.
Background: Lung computed tomography (CT) scan image registration is being used for lung function analysis such as ventilation. Given the high sensitivity of functional analyses to image registration errors, an image registration error scoring tool that can measure submillimeter image registration errors is needed.
Purpose: To propose an image registration error scoring tool, termed λ, whose spatial sensitivity can be used to quantify image registration errors in steep image gradient regions under realistic noise conditions.
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