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Assessment of geometrical accuracy of magnetic resonance images for radiation therapy of lung cancers

Koch, N; Liu, HH; Olsson, L E LU and Jackson, E F (2003) In Journal of Applied Clinical Medical Physics 4(4). p.64-352
Abstract

The purpose of this research was to investigate the geometrical accuracy of magnetic resonance (MR) images used in the radiation therapy treatment planning for lung cancer. In this study, the capability of MR imaging to acquire dynamic two-dimensional images was explored to access the motion of lung tumors. Due to a number of factors, including the use of a large field-of-view for the thorax, MR images are particularly subject to geometrical distortions caused by the inhomogeneity and gradient nonlinearity of the magnetic field. To quantify such distortions, we constructed a phantom, which approximated the dimensions of the upper thorax and included two air cavities. Evenly spaced vials containing contrast agent could be held in three... (More)

The purpose of this research was to investigate the geometrical accuracy of magnetic resonance (MR) images used in the radiation therapy treatment planning for lung cancer. In this study, the capability of MR imaging to acquire dynamic two-dimensional images was explored to access the motion of lung tumors. Due to a number of factors, including the use of a large field-of-view for the thorax, MR images are particularly subject to geometrical distortions caused by the inhomogeneity and gradient nonlinearity of the magnetic field. To quantify such distortions, we constructed a phantom, which approximated the dimensions of the upper thorax and included two air cavities. Evenly spaced vials containing contrast agent could be held in three directions with their cross-sections in the coronal, sagittal, and axial planes, respectively, within the air cavities. MR images of the phantom were acquired using fast spin echo (FSE) and fast gradient echo (fGRE) sequences. The positions of the vials according to their centers of mass were measured from the MR images and registered to the corresponding computed tomography images for comparison. Results showed the fGRE sequence exhibited no errors >2.0 mm in the sagittal and coronal planes, whereas the FSE sequence produced images with errors between 2.0 and 4.0 mm along the phantom's perimeter in the axial plane. On the basis of these results, the fGRE sequence was considered to be clinically acceptable in acquiring images in all sagittal and coronal planes tested. However, the spatial accuracy in periphery of the axial FSE images exceeded the acceptable criteria for the acquisition parameters used in this study.

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author
publishing date
type
Contribution to journal
publication status
published
keywords
Computer Simulation, Humans, Image Interpretation, Computer-Assisted, Lung Neoplasms, Magnetic Resonance Imaging, Models, Theoretical, Phantoms, Imaging, Quality Assurance, Health Care, Radiotherapy Planning, Computer-Assisted, Radiotherapy, Computer-Assisted
in
Journal of Applied Clinical Medical Physics
volume
4
issue
4
pages
13 pages
publisher
American College of Medical Physics
ISSN
1526-9914
DOI
10.1120/1.1617211
language
English
LU publication?
no
id
411db6b3-dfa8-43b3-a4ae-eb604d2ad6b0
date added to LUP
2016-08-16 13:18:07
date last changed
2016-08-19 16:42:06
@misc{411db6b3-dfa8-43b3-a4ae-eb604d2ad6b0,
  abstract     = {<p>The purpose of this research was to investigate the geometrical accuracy of magnetic resonance (MR) images used in the radiation therapy treatment planning for lung cancer. In this study, the capability of MR imaging to acquire dynamic two-dimensional images was explored to access the motion of lung tumors. Due to a number of factors, including the use of a large field-of-view for the thorax, MR images are particularly subject to geometrical distortions caused by the inhomogeneity and gradient nonlinearity of the magnetic field. To quantify such distortions, we constructed a phantom, which approximated the dimensions of the upper thorax and included two air cavities. Evenly spaced vials containing contrast agent could be held in three directions with their cross-sections in the coronal, sagittal, and axial planes, respectively, within the air cavities. MR images of the phantom were acquired using fast spin echo (FSE) and fast gradient echo (fGRE) sequences. The positions of the vials according to their centers of mass were measured from the MR images and registered to the corresponding computed tomography images for comparison. Results showed the fGRE sequence exhibited no errors &gt;2.0 mm in the sagittal and coronal planes, whereas the FSE sequence produced images with errors between 2.0 and 4.0 mm along the phantom's perimeter in the axial plane. On the basis of these results, the fGRE sequence was considered to be clinically acceptable in acquiring images in all sagittal and coronal planes tested. However, the spatial accuracy in periphery of the axial FSE images exceeded the acceptable criteria for the acquisition parameters used in this study.</p>},
  author       = {Koch, N and Liu, HH and Olsson, L E and Jackson, E F},
  issn         = {1526-9914},
  keyword      = {Computer Simulation,Humans,Image Interpretation, Computer-Assisted,Lung Neoplasms,Magnetic Resonance Imaging,Models, Theoretical,Phantoms, Imaging,Quality Assurance, Health Care,Radiotherapy Planning, Computer-Assisted,Radiotherapy, Computer-Assisted},
  language     = {eng},
  number       = {4},
  pages        = {64--352},
  publisher    = {ARRAY(0xd815ef0)},
  series       = {Journal of Applied Clinical Medical Physics},
  title        = {Assessment of geometrical accuracy of magnetic resonance images for radiation therapy of lung cancers},
  url          = {http://dx.doi.org/10.1120/1.1617211},
  volume       = {4},
  year         = {2003},
}