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Noise in polymer gel measurements using MRI.

Publication ,  Journal Article
Low, DA; Markman, J; Dempsey, JF; Mutic, S; Oldham, M; Venkatesan, R; Haacke, EM; Purdy, JA
Published in: Med Phys
August 2000

With the development of conformal radiotherapy, particularly intensity modulated radiation therapy (IMRT), there is a clear need for multidimensional dosimeters. A commercial polymerizing gel, BANG-2 gel (MGS Research, Inc., Guilford, CT), has recently been developed that shows potential as a multi-dimensional dosimeter. This study investigates and characterizes the noise and magnetic resonance (MR) artifacts from imaging BANG-2 gels. Seven cylindrical vials (4 cm diam, 20 cm length) were irradiated end on in a water bath and read using MRI (B0=1.5 T, TE=20 ms/100 ms, TR=3000 ms). The gel calibration compared the measured depth-dose distributions in water against the change in solvent-proton R2 relaxivity of the gel. A larger vial (13 cm diam, 14 cm length) was also irradiated to test the calibration accuracy in a vial of sufficient volume for dose distribution measurements. The calibration curve proved accurate to within 1.3% in determining the depth dose measured by the larger vial. An investigation of the voxel-to-voxel (IXIX 3 mm3) noise and sensitivity response curve showed that the voxel-to-voxel variation dominated the dose measurement uncertainty. The voxel-to-voxel standard deviation ranged from 0.2 Gy for the unirradiated gel to 0.7 Gy at 20 Gy. Slice-to-slice R2 magnitude deviations were also observed corresponding to 0.2 Gy. These variations limited the overall accuracy of the gel dose measurements and warrant an investigation of more accurate MR readout sequences.

Duke Scholars

Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

August 2000

Volume

27

Issue

8

Start / End Page

1814 / 1817

Location

United States

Related Subject Headings

  • Water
  • Reproducibility of Results
  • Radiotherapy, Conformal
  • Radiometry
  • Polymers
  • Nuclear Medicine & Medical Imaging
  • Models, Statistical
  • Magnetic Resonance Imaging
  • Gels
  • Dose-Response Relationship, Radiation
 

Citation

APA
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ICMJE
MLA
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Low, D. A., Markman, J., Dempsey, J. F., Mutic, S., Oldham, M., Venkatesan, R., … Purdy, J. A. (2000). Noise in polymer gel measurements using MRI. Med Phys, 27(8), 1814–1817. https://doi.org/10.1118/1.1287284
Low, D. A., J. Markman, J. F. Dempsey, S. Mutic, M. Oldham, R. Venkatesan, E. M. Haacke, and J. A. Purdy. “Noise in polymer gel measurements using MRI.Med Phys 27, no. 8 (August 2000): 1814–17. https://doi.org/10.1118/1.1287284.
Low DA, Markman J, Dempsey JF, Mutic S, Oldham M, Venkatesan R, et al. Noise in polymer gel measurements using MRI. Med Phys. 2000 Aug;27(8):1814–7.
Low, D. A., et al. “Noise in polymer gel measurements using MRI.Med Phys, vol. 27, no. 8, Aug. 2000, pp. 1814–17. Pubmed, doi:10.1118/1.1287284.
Low DA, Markman J, Dempsey JF, Mutic S, Oldham M, Venkatesan R, Haacke EM, Purdy JA. Noise in polymer gel measurements using MRI. Med Phys. 2000 Aug;27(8):1814–1817.

Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

August 2000

Volume

27

Issue

8

Start / End Page

1814 / 1817

Location

United States

Related Subject Headings

  • Water
  • Reproducibility of Results
  • Radiotherapy, Conformal
  • Radiometry
  • Polymers
  • Nuclear Medicine & Medical Imaging
  • Models, Statistical
  • Magnetic Resonance Imaging
  • Gels
  • Dose-Response Relationship, Radiation