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The effect of different lung densities on the accuracy of various radiotherapy dose calculation methods: Implications for tumour coverage

Aarup, Lasse Rye; Nahum, Alan E.; Zacharatou, Christina; Juhler-Nottrup, Trine; Knöös, Tommy LU ; Nystrom, Hakan; Specht, Lena; Wieslander, Elinore LU and Korreman, Stine S. (2009) In Radiotherapy and Oncology 91(3). p.405-414
Abstract
Purpose: To evaluate against Monte-Carlo the performance of various dose calculations algorithms regarding lung turnout coverage in stereotactic body radiotherapy (SBRT) conditions. Materials and methods: Dose distributions in virtual lung phantoms have been calculated using four commercial Treatment Planning System (TPS) algorithms and one Monte Carlo (MC) system (EGSnrc). We compared the performance of the algorithms in calculating the target dose for different degrees of lung inflation. The phantoms had a cubic 'body' and 'lung' and a central 2-cm diameter spherical 'tumour' (the body and turnout have unit density). The lung tissue was assigned five densities (rho(lung)): 0.01, 0.1, 0.2, 0.4 and 1 g/cm(3). Four-field treatment plans... (More)
Purpose: To evaluate against Monte-Carlo the performance of various dose calculations algorithms regarding lung turnout coverage in stereotactic body radiotherapy (SBRT) conditions. Materials and methods: Dose distributions in virtual lung phantoms have been calculated using four commercial Treatment Planning System (TPS) algorithms and one Monte Carlo (MC) system (EGSnrc). We compared the performance of the algorithms in calculating the target dose for different degrees of lung inflation. The phantoms had a cubic 'body' and 'lung' and a central 2-cm diameter spherical 'tumour' (the body and turnout have unit density). The lung tissue was assigned five densities (rho(lung)): 0.01, 0.1, 0.2, 0.4 and 1 g/cm(3). Four-field treatment plans were calculated with 6- and 18 MV narrow beams for each value of rho(lung). We considered the Pencil Beam Convolution (PBCEl) and the Analytical Anisotropic Algorithm (AAA(ECl)) from Varian Eclipse and the Pencil Beam Convolution (PBCOMP) and the Collapsed Cone Convolution (CCCOMP) algorithms from Oncentra MasterPlan. Results: When changing rho(lung) from 0.4 to 0.1 g/cm(3), the MC median target dose decreased from 89.2% to 74.9% for 6 MV and from 83.3% to 61.6% for 18 MV (of dose maximum in the homogenous case at both energies), while for both PB algorithms the median target dose was virtually independent of lung density. Conclusions: Both PB algorithms overestimated the target dose, the overestimation increasing as rho(lung) decreased. Concerning target dose, the AAA(ECl) and CCCOMP algorithms appear to be adequate alternatives to MC. (C) 2009 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and oncology 91 (2009) 405-414 (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Density variations, PBC, Gating, 4D-CT, CCC, AAA, Monte Carlo, Lung cancer, Radiotherapy
in
Radiotherapy and Oncology
volume
91
issue
3
pages
405 - 414
publisher
Elsevier
external identifiers
  • wos:000266749200020
  • scopus:65649096221
ISSN
1879-0887
DOI
10.1016/j.radonc.2009.01.008
language
English
LU publication?
yes
id
d80ee22b-d2ee-4397-baae-0ba8e1ede80b (old id 1441890)
date added to LUP
2009-07-27 14:56:14
date last changed
2017-10-01 03:54:02
@article{d80ee22b-d2ee-4397-baae-0ba8e1ede80b,
  abstract     = {Purpose: To evaluate against Monte-Carlo the performance of various dose calculations algorithms regarding lung turnout coverage in stereotactic body radiotherapy (SBRT) conditions. Materials and methods: Dose distributions in virtual lung phantoms have been calculated using four commercial Treatment Planning System (TPS) algorithms and one Monte Carlo (MC) system (EGSnrc). We compared the performance of the algorithms in calculating the target dose for different degrees of lung inflation. The phantoms had a cubic 'body' and 'lung' and a central 2-cm diameter spherical 'tumour' (the body and turnout have unit density). The lung tissue was assigned five densities (rho(lung)): 0.01, 0.1, 0.2, 0.4 and 1 g/cm(3). Four-field treatment plans were calculated with 6- and 18 MV narrow beams for each value of rho(lung). We considered the Pencil Beam Convolution (PBCEl) and the Analytical Anisotropic Algorithm (AAA(ECl)) from Varian Eclipse and the Pencil Beam Convolution (PBCOMP) and the Collapsed Cone Convolution (CCCOMP) algorithms from Oncentra MasterPlan. Results: When changing rho(lung) from 0.4 to 0.1 g/cm(3), the MC median target dose decreased from 89.2% to 74.9% for 6 MV and from 83.3% to 61.6% for 18 MV (of dose maximum in the homogenous case at both energies), while for both PB algorithms the median target dose was virtually independent of lung density. Conclusions: Both PB algorithms overestimated the target dose, the overestimation increasing as rho(lung) decreased. Concerning target dose, the AAA(ECl) and CCCOMP algorithms appear to be adequate alternatives to MC. (C) 2009 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and oncology 91 (2009) 405-414},
  author       = {Aarup, Lasse Rye and Nahum, Alan E. and Zacharatou, Christina and Juhler-Nottrup, Trine and Knöös, Tommy and Nystrom, Hakan and Specht, Lena and Wieslander, Elinore and Korreman, Stine S.},
  issn         = {1879-0887},
  keyword      = {Density variations,PBC,Gating,4D-CT,CCC,AAA,Monte Carlo,Lung cancer,Radiotherapy},
  language     = {eng},
  number       = {3},
  pages        = {405--414},
  publisher    = {Elsevier},
  series       = {Radiotherapy and Oncology},
  title        = {The effect of different lung densities on the accuracy of various radiotherapy dose calculation methods: Implications for tumour coverage},
  url          = {http://dx.doi.org/10.1016/j.radonc.2009.01.008},
  volume       = {91},
  year         = {2009},
}