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Effect of set-up uncertainties on the dose distribution in the match region of supraclavicular and tangential breast fields

Idzes, M H; Holmberg, Ola LU ; Mijnheer, B J and Huizenga, H (1998) In Radiotherapy and Oncology 46(1). p.91-98
Abstract
BACKGROUND: The objective of this paper is to illustrate the effect of a gap of 5 mm, an overlap of 5 mm and a perfect match on the dose distribution across the junction of tangential breast fields and adjacent supraclavicular and axillary fields. MATERIALS AND METHODS: For this purpose film dosimetry was applied to measure relative dose distributions in two sagittal planes in an anthropomorphic breast phantom having cork lungs, simulating a radiation therapy treatment of the breast and adjacent supraclavicular lymph nodes. Two different treatment techniques, an SSD match technique and a geometrically exact isocentric match technique, as routinely applied in the two institutes were examined. The three-dimensional treatment planning system... (More)
BACKGROUND: The objective of this paper is to illustrate the effect of a gap of 5 mm, an overlap of 5 mm and a perfect match on the dose distribution across the junction of tangential breast fields and adjacent supraclavicular and axillary fields. MATERIALS AND METHODS: For this purpose film dosimetry was applied to measure relative dose distributions in two sagittal planes in an anthropomorphic breast phantom having cork lungs, simulating a radiation therapy treatment of the breast and adjacent supraclavicular lymph nodes. Two different treatment techniques, an SSD match technique and a geometrically exact isocentric match technique, as routinely applied in the two institutes were examined. The three-dimensional treatment planning system of each institute was used to calculate the dose distribution in the match region of the supraclavicular fields and the two opposing tangential fields. The measured and calculated dose distributions were evaluated and compared along lines in two sagittal planes from the supraclavicular fields down to the tangential fields crossing the match planes. These dose distributions in the match region were extremely dependent on the set-up of the fields. RESULTS: Although the reproducibility of the film measurements was within 2%, it became clear that the set-up of the fields to achieve a gap of 5 mm, a perfect match or an overlap of 5 mm required a lot of attention, even when using a phantom. CONCLUSIONS: It can be concluded that in clinical practice, these set-up difficulties do influence the dose distribution in the match region much more than the systematic uncertainties in the dose calculation algorithms of the treatment planning systems and the type of treatment technique. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Radiotherapy and Oncology
volume
46
issue
1
pages
91 - 98
publisher
Elsevier
external identifiers
  • scopus:0031929368
ISSN
1879-0887
DOI
10.1016/S0167-8140(97)00170-9
language
English
LU publication?
no
id
0e227b10-f16c-4e8a-a31d-a2abdf0c0ba5 (old id 1296568)
date added to LUP
2009-07-31 12:49:03
date last changed
2017-01-15 03:35:11
@article{0e227b10-f16c-4e8a-a31d-a2abdf0c0ba5,
  abstract     = {BACKGROUND: The objective of this paper is to illustrate the effect of a gap of 5 mm, an overlap of 5 mm and a perfect match on the dose distribution across the junction of tangential breast fields and adjacent supraclavicular and axillary fields. MATERIALS AND METHODS: For this purpose film dosimetry was applied to measure relative dose distributions in two sagittal planes in an anthropomorphic breast phantom having cork lungs, simulating a radiation therapy treatment of the breast and adjacent supraclavicular lymph nodes. Two different treatment techniques, an SSD match technique and a geometrically exact isocentric match technique, as routinely applied in the two institutes were examined. The three-dimensional treatment planning system of each institute was used to calculate the dose distribution in the match region of the supraclavicular fields and the two opposing tangential fields. The measured and calculated dose distributions were evaluated and compared along lines in two sagittal planes from the supraclavicular fields down to the tangential fields crossing the match planes. These dose distributions in the match region were extremely dependent on the set-up of the fields. RESULTS: Although the reproducibility of the film measurements was within 2%, it became clear that the set-up of the fields to achieve a gap of 5 mm, a perfect match or an overlap of 5 mm required a lot of attention, even when using a phantom. CONCLUSIONS: It can be concluded that in clinical practice, these set-up difficulties do influence the dose distribution in the match region much more than the systematic uncertainties in the dose calculation algorithms of the treatment planning systems and the type of treatment technique.},
  author       = {Idzes, M H and Holmberg, Ola and Mijnheer, B J and Huizenga, H},
  issn         = {1879-0887},
  language     = {eng},
  number       = {1},
  pages        = {91--98},
  publisher    = {Elsevier},
  series       = {Radiotherapy and Oncology},
  title        = {Effect of set-up uncertainties on the dose distribution in the match region of supraclavicular and tangential breast fields},
  url          = {http://dx.doi.org/10.1016/S0167-8140(97)00170-9},
  volume       = {46},
  year         = {1998},
}