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Modelling the dynamic dose response of an nMAG polymer gel dosimeter.

Ceberg, Sofie LU ; Lepage, Martin; Bäck, Sven LU ; Gustafsson, Helen and Ceberg, Crister LU (2012) In Physics in Medicine and Biology 57(15). p.4845-4853
Abstract
Gel dosimetry measures the absorbed radiation dose with high spatial resolution in 3D. However, recently published data show that the response of metacrylic-based polymer gels depends on the segmented delivery pattern, which could potentially be a considerable disadvantage for measurements of modern dynamic radiotherapy techniques. The aim of this study is to design a dynamic compartment model for the response of a gel dosimeter, exposed to an arbitrary irradiation pattern (segmented delivery and intensity modulation), in order to evaluate the associated effects on absorbed dose measurements. The model is based on the separation of the protons affecting the magnetic resonance signal (i.e. the R2 value) into six compartments, described by a... (More)
Gel dosimetry measures the absorbed radiation dose with high spatial resolution in 3D. However, recently published data show that the response of metacrylic-based polymer gels depends on the segmented delivery pattern, which could potentially be a considerable disadvantage for measurements of modern dynamic radiotherapy techniques. The aim of this study is to design a dynamic compartment model for the response of a gel dosimeter, exposed to an arbitrary irradiation pattern (segmented delivery and intensity modulation), in order to evaluate the associated effects on absorbed dose measurements. The model is based on the separation of the protons affecting the magnetic resonance signal (i.e. the R2 value) into six compartments, described by a set of differential equations. The model is used to calculate R2 values for a number of different segmented delivery patterns between 0-4 Gy over 1-33 fractions. Very good agreement is found between calculated and measured R2 values, with an average difference of 0.3 ± 1.1% (1 SD). The model is also used to predict the behaviour of a gel dosimeter exposed to irradiation according to typical IMRT, VMAT and respiratory gating scenarios. The calculated R2 values are approximately independent of the segmented delivery, given that the same total dose is delivered during the same total time. It is concluded that this study helps to improve the theoretical understanding of the dependence of metacrylic-based polymer gel response to segmented radiation delivery. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physics in Medicine and Biology
volume
57
issue
15
pages
4845 - 4853
publisher
IOP Publishing
external identifiers
  • wos:000306521900011
  • pmid:22797664
  • scopus:84863921324
ISSN
1361-6560
DOI
10.1088/0031-9155/57/15/4845
language
English
LU publication?
yes
id
0995be70-b019-4897-bdce-2f5b95edfc94 (old id 2967114)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/22797664?dopt=Abstract
date added to LUP
2012-08-09 19:32:32
date last changed
2017-01-01 04:00:08
@article{0995be70-b019-4897-bdce-2f5b95edfc94,
  abstract     = {Gel dosimetry measures the absorbed radiation dose with high spatial resolution in 3D. However, recently published data show that the response of metacrylic-based polymer gels depends on the segmented delivery pattern, which could potentially be a considerable disadvantage for measurements of modern dynamic radiotherapy techniques. The aim of this study is to design a dynamic compartment model for the response of a gel dosimeter, exposed to an arbitrary irradiation pattern (segmented delivery and intensity modulation), in order to evaluate the associated effects on absorbed dose measurements. The model is based on the separation of the protons affecting the magnetic resonance signal (i.e. the R2 value) into six compartments, described by a set of differential equations. The model is used to calculate R2 values for a number of different segmented delivery patterns between 0-4 Gy over 1-33 fractions. Very good agreement is found between calculated and measured R2 values, with an average difference of 0.3 ± 1.1% (1 SD). The model is also used to predict the behaviour of a gel dosimeter exposed to irradiation according to typical IMRT, VMAT and respiratory gating scenarios. The calculated R2 values are approximately independent of the segmented delivery, given that the same total dose is delivered during the same total time. It is concluded that this study helps to improve the theoretical understanding of the dependence of metacrylic-based polymer gel response to segmented radiation delivery.},
  author       = {Ceberg, Sofie and Lepage, Martin and Bäck, Sven and Gustafsson, Helen and Ceberg, Crister},
  issn         = {1361-6560},
  language     = {eng},
  number       = {15},
  pages        = {4845--4853},
  publisher    = {IOP Publishing},
  series       = {Physics in Medicine and Biology},
  title        = {Modelling the dynamic dose response of an nMAG polymer gel dosimeter.},
  url          = {http://dx.doi.org/10.1088/0031-9155/57/15/4845},
  volume       = {57},
  year         = {2012},
}