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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 (1996) In Medical Dosimetry 21(1). p.38-38
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 cm[super:2] are studied for photon beam energies of [super:60]Co, 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... (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 cm[super:2] are studied for photon beam energies of [super:60]Co, 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 over-estimation of the calculated dose in the cylindrical configuration up to about 6% for a 20 x 20-cm[super:2] [super:60]Co 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
Head and neck region, Pencil beam algorithm, Dose planning, Radiotherapy, Patient modelling
in
Medical Dosimetry
volume
21
issue
1
pages
38 - 38
publisher
Elsevier
ISSN
1873-4022
DOI
10.1016/0958-3947(95)01609-0
language
English
LU publication?
yes
id
486c843e-72fc-4d5e-ac40-8ea9646ce230 (old id 1111126)
date added to LUP
2008-07-24 08:56:18
date last changed
2016-09-13 16:23:48
@article{486c843e-72fc-4d5e-ac40-8ea9646ce230,
  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 cm[super:2] are studied for photon beam energies of [super:60]Co, 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 over-estimation of the calculated dose in the cylindrical configuration up to about 6% for a 20 x 20-cm[super:2] [super:60]Co 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         = {1873-4022},
  keyword      = {Head and neck region,Pencil beam algorithm,Dose planning,Radiotherapy,Patient modelling},
  language     = {eng},
  number       = {1},
  pages        = {38--38},
  publisher    = {Elsevier},
  series       = {Medical Dosimetry},
  title        = {Limitations of a pencil beam approach to photon dose calculations in the head and neck region},
  url          = {http://dx.doi.org/10.1016/0958-3947(95)01609-0},
  volume       = {21},
  year         = {1996},
}