Motion modeling from 4D MR images of liver simulating phantom
- Resource Type
- Authors
- Kavaluus, Henna; Koivula, Lauri; Salli, Eero; Seppälä, Tiina; Saarilahti, Kauko; Tenhunen, Mikko
- Source
- Journal of applied clinical medical physics. 23(7)
- Subject
- liver 4D-MRI
SBRT
Radiation
Phantoms, Imaging
3126 Surgery, anesthesiology, intensive care, radiology
Magnetic Resonance Imaging
Motion
Liver
DEFORMATION
RADIATION-THERAPY
Humans
Radiology, Nuclear Medicine and imaging
Four-Dimensional Computed Tomography
deformable image registration
Instrumentation
motion model
Retrospective Studies
- Language
- ISSN
- 1526-9914
Background and purpose A novel method of retrospective liver modeling was developed based on four-dimensional magnetic resonance (4D-MR) images. The 4D-MR images will be utilized in generation of the subject-specific deformable liver model to be used in radiotherapy planning (RTP). The purpose of this study was to test and validate the developed 4D-magnetic resonance imaging (MRI) method with extensive phantom tests. We also aimed to build a motion model with image registration methods from liver simulating phantom images. Materials and methods A deformable phantom was constructed by combining deformable tissue-equivalent material and a programmable 4D CIRS-platform. The phantom was imaged in 1.5 T MRI scanner with T2-weighted 4D SSFSE and T1-weighted Ax dual-echo Dixon SPGR sequences, and in computed tomography (CT). In addition, geometric distortion of the 4D sequence was measured with a GRADE phantom. The motion model was developed; the phases of the 4D-MRI were used as surrogate data, and displacement vector fields (DVF's) were used as a motion measurement. The motion model and the developed 4D-MRI method were evaluated and validated with extensive tests. Result The 4D-MRI method enabled an accuracy of 2 mm using our deformable phantom compared to the 4D-CT. Results showed a mean accuracy of