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Introducing multiple treatment plan-based comparison to investigate the performance of gantry angle optimisation (GAO) in IMRT for head and neck cancer

Thor, Maria; Benedek, Hunor LU ; Knöös, Tommy LU ; Engström, Per LU ; Behrens, Claus F.; Hauer, Anna Karlsson; Sjostrom, David and Ceberg, Crister (2012) In Acta Oncologica 51(6). p.743-751
Abstract
Background and purpose. The purpose of this study was to evaluate the performance of gantry angle optimisation (GAO) compared to equidistant beam geometry for two inverse treatment planning systems (TPSs) by utilising the information obtained from a range of treatment plans. Material and methods. The comparison was based on treatment plans generated for four different head and neck (H&N) cancer cases using two inverse treatment planning systems (TPSs); Varian Eclipse (TM) representing dynamic MLC intensity modulated radiotherapy (IMRT) and Oncentra (R) Masterplan representing segmented MLC-based IMRT. The patient cases were selected on the criterion of representing different degrees of overlap between the planning target volume (PTV)... (More)
Background and purpose. The purpose of this study was to evaluate the performance of gantry angle optimisation (GAO) compared to equidistant beam geometry for two inverse treatment planning systems (TPSs) by utilising the information obtained from a range of treatment plans. Material and methods. The comparison was based on treatment plans generated for four different head and neck (H&N) cancer cases using two inverse treatment planning systems (TPSs); Varian Eclipse (TM) representing dynamic MLC intensity modulated radiotherapy (IMRT) and Oncentra (R) Masterplan representing segmented MLC-based IMRT. The patient cases were selected on the criterion of representing different degrees of overlap between the planning target volume (PTV) and the investigated organ at risk, the ipsilateral parotid gland. For each case, a number of 'Pareto optimal' plans were generated in order to investigate the trade-off between the under-dosage to the PTV (V-PTV,V-D (< 95%)) or the decrease in dose homogeneity (D-5-D-95) to the PTV as a function of the mean absorbed dose to the ipsilateral parotid gland (< D >(parotid gland)). Results. For the Eclipse system, GAO had a clear advantage for the cases with smallest overlap (Cases 1 and 2). The set of data points, representing the underlying trade-offs, generated with and without using GAO were, however, not as clearly separated for the cases with larger overlap (Cases 3 and 4). With the OMP system, the difference was less pronounced for all cases. The Eclipse GAO displays the most favourable trade-off for all H&N cases. Conclusions. We have found differences in the effectiveness of GAO as compared to equidistant beam geometry, in terms of handling conflicting trade-offs for two commercial inverse TPSs. A comparison, based on a range of treatment plans, as developed in this study, is likely to improve the understanding of conflicting trade-offs and might apply to other thorough comparison techniques. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Acta Oncologica
volume
51
issue
6
pages
743 - 751
publisher
Taylor & Francis
external identifiers
  • wos:000306480600008
  • scopus:84863858396
ISSN
1651-226X
DOI
10.3109/0284186X.2012.673733
language
English
LU publication?
yes
id
038d2d64-eeb4-4658-b403-b9436432b75a (old id 2979307)
date added to LUP
2012-09-03 07:16:07
date last changed
2017-01-01 06:12:11
@article{038d2d64-eeb4-4658-b403-b9436432b75a,
  abstract     = {Background and purpose. The purpose of this study was to evaluate the performance of gantry angle optimisation (GAO) compared to equidistant beam geometry for two inverse treatment planning systems (TPSs) by utilising the information obtained from a range of treatment plans. Material and methods. The comparison was based on treatment plans generated for four different head and neck (H&amp;N) cancer cases using two inverse treatment planning systems (TPSs); Varian Eclipse (TM) representing dynamic MLC intensity modulated radiotherapy (IMRT) and Oncentra (R) Masterplan representing segmented MLC-based IMRT. The patient cases were selected on the criterion of representing different degrees of overlap between the planning target volume (PTV) and the investigated organ at risk, the ipsilateral parotid gland. For each case, a number of 'Pareto optimal' plans were generated in order to investigate the trade-off between the under-dosage to the PTV (V-PTV,V-D (&lt; 95%)) or the decrease in dose homogeneity (D-5-D-95) to the PTV as a function of the mean absorbed dose to the ipsilateral parotid gland (&lt; D &gt;(parotid gland)). Results. For the Eclipse system, GAO had a clear advantage for the cases with smallest overlap (Cases 1 and 2). The set of data points, representing the underlying trade-offs, generated with and without using GAO were, however, not as clearly separated for the cases with larger overlap (Cases 3 and 4). With the OMP system, the difference was less pronounced for all cases. The Eclipse GAO displays the most favourable trade-off for all H&amp;N cases. Conclusions. We have found differences in the effectiveness of GAO as compared to equidistant beam geometry, in terms of handling conflicting trade-offs for two commercial inverse TPSs. A comparison, based on a range of treatment plans, as developed in this study, is likely to improve the understanding of conflicting trade-offs and might apply to other thorough comparison techniques.},
  author       = {Thor, Maria and Benedek, Hunor and Knöös, Tommy and Engström, Per and Behrens, Claus F. and Hauer, Anna Karlsson and Sjostrom, David and Ceberg, Crister},
  issn         = {1651-226X},
  language     = {eng},
  number       = {6},
  pages        = {743--751},
  publisher    = {Taylor & Francis},
  series       = {Acta Oncologica},
  title        = {Introducing multiple treatment plan-based comparison to investigate the performance of gantry angle optimisation (GAO) in IMRT for head and neck cancer},
  url          = {http://dx.doi.org/10.3109/0284186X.2012.673733},
  volume       = {51},
  year         = {2012},
}