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Limitations of a pencil beam approach to photon dose calculations in the head and neck region

Hurkmans, Coen; Knöös, Tommy LU ; Nilsson, Per LU ; Svahn-Tapper, Gudrun LU and Danielsson, Hans (1995) In Radiotherapy and Oncology 37(1). p.74-80
Abstract
The inherent limitations of a specific pencil beam model have been studied when applied to a cylindrical geometry simulating the neck region. A comparison is made between measured and calculated absorbed dose in a cylindrical phantom. The goal is to quantify the deviations in the absorbed dose level, i.e., the dose per monitor unit, when photons are used for the treatment of head and neck tumours. Square fields ranging from 5 x 5 up to 30 x 30 cm2 are studied for photon beam energies of 60Co, 4, 6 and 18 MV. Ionisation chamber measurements have been performed in the cylinder as well as in two other configurations in order to trace the origin of possible deviations. For 18 MV no significant deviations are found between measurement and... (More)
The inherent limitations of a specific pencil beam model have been studied when applied to a cylindrical geometry simulating the neck region. A comparison is made between measured and calculated absorbed dose in a cylindrical phantom. The goal is to quantify the deviations in the absorbed dose level, i.e., the dose per monitor unit, when photons are used for the treatment of head and neck tumours. Square fields ranging from 5 x 5 up to 30 x 30 cm2 are studied for photon beam energies of 60Co, 4, 6 and 18 MV. Ionisation chamber measurements have been performed in the cylinder as well as in two other configurations in order to trace the origin of possible deviations. For 18 MV no significant deviations are found between measurement and calculation in the cylindrical configuration. For the lower energies, an overestimation of the calculated dose in the cylindrical configuration up to about 6% for a 20 x 20-cm2 60Co field has been found. These deviations have been traced to the basic approximation for the integration volume for phantom scatter calculations inherent in this pencil beam implementation. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Radiotherapy, Dose planning, Pencil beam algorithm, Head and neck region, Patient modelling
in
Radiotherapy and Oncology
volume
37
issue
1
pages
74 - 80
publisher
Elsevier
external identifiers
  • pmid:8539461
  • scopus:0028822857
ISSN
1879-0887
DOI
10.1016/0167-8140(95)01609-K
language
English
LU publication?
yes
id
b0050a7d-b45b-44eb-9e26-b2f7033bf0a8 (old id 1109000)
date added to LUP
2008-07-25 11:55:45
date last changed
2017-01-01 05:02:52
@article{b0050a7d-b45b-44eb-9e26-b2f7033bf0a8,
  abstract     = {The inherent limitations of a specific pencil beam model have been studied when applied to a cylindrical geometry simulating the neck region. A comparison is made between measured and calculated absorbed dose in a cylindrical phantom. The goal is to quantify the deviations in the absorbed dose level, i.e., the dose per monitor unit, when photons are used for the treatment of head and neck tumours. Square fields ranging from 5 x 5 up to 30 x 30 cm2 are studied for photon beam energies of 60Co, 4, 6 and 18 MV. Ionisation chamber measurements have been performed in the cylinder as well as in two other configurations in order to trace the origin of possible deviations. For 18 MV no significant deviations are found between measurement and calculation in the cylindrical configuration. For the lower energies, an overestimation of the calculated dose in the cylindrical configuration up to about 6% for a 20 x 20-cm2 60Co field has been found. These deviations have been traced to the basic approximation for the integration volume for phantom scatter calculations inherent in this pencil beam implementation.},
  author       = {Hurkmans, Coen and Knöös, Tommy and Nilsson, Per and Svahn-Tapper, Gudrun and Danielsson, Hans},
  issn         = {1879-0887},
  keyword      = {Radiotherapy,Dose planning,Pencil beam algorithm,Head and neck region,Patient modelling},
  language     = {eng},
  number       = {1},
  pages        = {74--80},
  publisher    = {Elsevier},
  series       = {Radiotherapy and Oncology},
  title        = {Limitations of a pencil beam approach to photon dose calculations in the head and neck region},
  url          = {http://dx.doi.org/10.1016/0167-8140(95)01609-K},
  volume       = {37},
  year         = {1995},
}