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Modelling of post-irradiation events in polymer gel dosimeters

Lepage, M; Whittaker, A K; Rintoul, L; Bäck, Sven LU and Baldock, C (2001) In Physics in Medicine and Biology 46(11). p.2827-2839
Abstract
The nuclear magnetic resonance (NMR) spin-spin relaxation time (T2) is related to the radiation-dependent concentration of polymer formed in polymer gel dosimeters manufactured from monomers in an aqueous gelatin matrix. Changes in T2 with time post-irradiation have been reported in the literature but their nature is not fully understood. We investigated those changes with time after irradiation using FT-Raman spectroscopy and the precise determination of T2 at high magnetic field in a polymer gel dosimeter. A model of fast exchange of magnetization taking into account ongoing gelation and strengthening of the gelatin matrix as well as the polymerization of the monomers with time is presented. Published data on the changes of T2 in gelatin... (More)
The nuclear magnetic resonance (NMR) spin-spin relaxation time (T2) is related to the radiation-dependent concentration of polymer formed in polymer gel dosimeters manufactured from monomers in an aqueous gelatin matrix. Changes in T2 with time post-irradiation have been reported in the literature but their nature is not fully understood. We investigated those changes with time after irradiation using FT-Raman spectroscopy and the precise determination of T2 at high magnetic field in a polymer gel dosimeter. A model of fast exchange of magnetization taking into account ongoing gelation and strengthening of the gelatin matrix as well as the polymerization of the monomers with time is presented. Published data on the changes of T2 in gelatin gels as a function of post-manufacture time are used and fitted closely by the model presented. The same set of parameters characterizing the variations of T2 in gelatin gels and the increasing concentration of polymer determined from FT-Raman spectroscopy are used successfully in the modelling of irradiated polymer gel dosimeters. Minimal variations in T2 in an irradiated PAG dosimeter are observed after 13 h. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physics in Medicine and Biology
volume
46
issue
11
pages
2827 - 2839
publisher
IOP Publishing
external identifiers
  • wos:000172331400005
  • scopus:0035155677
ISSN
1361-6560
DOI
10.1088/0031-9155/46/11/305
language
English
LU publication?
yes
id
3b364925-d58c-433b-94ae-c5664938ad02 (old id 1297219)
date added to LUP
2009-07-15 09:24:32
date last changed
2018-05-29 10:18:51
@article{3b364925-d58c-433b-94ae-c5664938ad02,
  abstract     = {The nuclear magnetic resonance (NMR) spin-spin relaxation time (T2) is related to the radiation-dependent concentration of polymer formed in polymer gel dosimeters manufactured from monomers in an aqueous gelatin matrix. Changes in T2 with time post-irradiation have been reported in the literature but their nature is not fully understood. We investigated those changes with time after irradiation using FT-Raman spectroscopy and the precise determination of T2 at high magnetic field in a polymer gel dosimeter. A model of fast exchange of magnetization taking into account ongoing gelation and strengthening of the gelatin matrix as well as the polymerization of the monomers with time is presented. Published data on the changes of T2 in gelatin gels as a function of post-manufacture time are used and fitted closely by the model presented. The same set of parameters characterizing the variations of T2 in gelatin gels and the increasing concentration of polymer determined from FT-Raman spectroscopy are used successfully in the modelling of irradiated polymer gel dosimeters. Minimal variations in T2 in an irradiated PAG dosimeter are observed after 13 h.},
  author       = {Lepage, M and Whittaker, A K and Rintoul, L and Bäck, Sven and Baldock, C},
  issn         = {1361-6560},
  language     = {eng},
  number       = {11},
  pages        = {2827--2839},
  publisher    = {IOP Publishing},
  series       = {Physics in Medicine and Biology},
  title        = {Modelling of post-irradiation events in polymer gel dosimeters},
  url          = {http://dx.doi.org/10.1088/0031-9155/46/11/305},
  volume       = {46},
  year         = {2001},
}