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Magnetization transfer imaging for polymer gel dosimetry

Lepage, M; McMahon, K; Galloway, GJ; De Deene, Y; Bäck, Sven LU and Baldock, C (2002) In Physics in Medicine and Biology 47(11). p.1881-1890
Abstract
Off-resonance RF pre-saturation was used to obtain contrast in MRI images of polymer gel dosimeters irradiated to doses up to 50 Gy. Two different polymer gel dosimeters composed of 2-hydroxyethyl-acryl ate or methacrylic acid monomers mixed with N, N'-methylene-bisacrylamide (BIS), dispersed in an aqueous gelatin matrix were evaluated. Radiation-induced polymerization of the co-monomers generates a fast-relaxing insoluble polymer. Saturation of the polymer using off-resonance Gaussian RF pulses prior to a spin-echo read-out with a short echo time leads to contrast that is dependent on the absorbed dose. This contrast is attributed to magnetization transfer (MT) between free water and the polymer, and direct saturation of water was found... (More)
Off-resonance RF pre-saturation was used to obtain contrast in MRI images of polymer gel dosimeters irradiated to doses up to 50 Gy. Two different polymer gel dosimeters composed of 2-hydroxyethyl-acryl ate or methacrylic acid monomers mixed with N, N'-methylene-bisacrylamide (BIS), dispersed in an aqueous gelatin matrix were evaluated. Radiation-induced polymerization of the co-monomers generates a fast-relaxing insoluble polymer. Saturation of the polymer using off-resonance Gaussian RF pulses prior to a spin-echo read-out with a short echo time leads to contrast that is dependent on the absorbed dose. This contrast is attributed to magnetization transfer (MT) between free water and the polymer, and direct saturation of water was found to be negligible under the prevailing experimental conditions. The usefulness of MT imaging was assessed by computing the dose resolution obtained with this technique. We found a low value of dose resolution over a wide range of doses could be obtained with a single experiment. This is an advantage over multiple spin echo (MSE) experiments using a single echo spacing where an optimal dose resolution is achieved over only very limited ranges of doses. The results suggest MT imaging protocols may be developed into a useful tool for polymer gel dosimetry. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physics in Medicine and Biology
volume
47
issue
11
pages
1881 - 1890
publisher
IOP Publishing
external identifiers
  • wos:000176454300004
  • pmid:12108773
  • scopus:0037035839
ISSN
1361-6560
language
English
LU publication?
yes
id
9fb00bf3-6172-4dfa-922e-9582c897bc41 (old id 334279)
date added to LUP
2007-11-14 13:27:30
date last changed
2017-07-23 03:51:00
@article{9fb00bf3-6172-4dfa-922e-9582c897bc41,
  abstract     = {Off-resonance RF pre-saturation was used to obtain contrast in MRI images of polymer gel dosimeters irradiated to doses up to 50 Gy. Two different polymer gel dosimeters composed of 2-hydroxyethyl-acryl ate or methacrylic acid monomers mixed with N, N'-methylene-bisacrylamide (BIS), dispersed in an aqueous gelatin matrix were evaluated. Radiation-induced polymerization of the co-monomers generates a fast-relaxing insoluble polymer. Saturation of the polymer using off-resonance Gaussian RF pulses prior to a spin-echo read-out with a short echo time leads to contrast that is dependent on the absorbed dose. This contrast is attributed to magnetization transfer (MT) between free water and the polymer, and direct saturation of water was found to be negligible under the prevailing experimental conditions. The usefulness of MT imaging was assessed by computing the dose resolution obtained with this technique. We found a low value of dose resolution over a wide range of doses could be obtained with a single experiment. This is an advantage over multiple spin echo (MSE) experiments using a single echo spacing where an optimal dose resolution is achieved over only very limited ranges of doses. The results suggest MT imaging protocols may be developed into a useful tool for polymer gel dosimetry.},
  author       = {Lepage, M and McMahon, K and Galloway, GJ and De Deene, Y and Bäck, Sven and Baldock, C},
  issn         = {1361-6560},
  language     = {eng},
  number       = {11},
  pages        = {1881--1890},
  publisher    = {IOP Publishing},
  series       = {Physics in Medicine and Biology},
  title        = {Magnetization transfer imaging for polymer gel dosimetry},
  volume       = {47},
  year         = {2002},
}