Prediction of stopping-power ratios in flattening-filter free beams.
Ceberg, Crister LU
; Johnsson, Stefan
; Dalaryd, Mårten
LU
and Knöös, Tommy
LU
(2010)
In Medical Physics
37(3).
p.1164-1168
- Abstract
- PURPOSE: In recent years, there has been an increasing interest in flattening-filter free (FFF) beams. However, since the removal of the flattening filter will affect both the mean and the variance of the energy spectrum, current beam-quality specifiers may not be adequate for reference dosimetry in such beams. The purpose of this work was to investigate an alternative, more general beam-quality specifier. METHODS: The beam-quality specifier used in this work was a combination of the kerma-weighted mean and the coefficient of variation of the linear attenuation coefficient in water. These parameters can in theory be determined from narrow-beam transmission measurements using a miniphantom "in-air," which is a measurement condition well... (More)
- PURPOSE: In recent years, there has been an increasing interest in flattening-filter free (FFF) beams. However, since the removal of the flattening filter will affect both the mean and the variance of the energy spectrum, current beam-quality specifiers may not be adequate for reference dosimetry in such beams. The purpose of this work was to investigate an alternative, more general beam-quality specifier. METHODS: The beam-quality specifier used in this work was a combination of the kerma-weighted mean and the coefficient of variation of the linear attenuation coefficient in water. These parameters can in theory be determined from narrow-beam transmission measurements using a miniphantom "in-air," which is a measurement condition well suited also to small and nonstandard fields. The relation between the Spencer-Attix stopping-power ratios and this novel beam-quality specifier was described by a simple polynomial. For reference, the authors used Monte Carlo calculated spectra and stopping-power data for nine different beams, with and without flattening filter. RESULTS: The polynomial coefficients were obtained by least-squares optimization. For all beams included in this investigation, the average of the differences between the predicted and the Monte Carlo calculated stopping-power ratios was 0.02 +/- 0.17% (1 SD) (including TomoTherapy and CyberKnife example beams). CONCLUSIONS: An alternative dual-parameter beam-quality specifier was investigated. The evaluation suggests that it can be used successfully to predict stopping-power ratios in FFF as well as conventional beams, regardless of filtration. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1595370
- author
- Ceberg, Crister
LU
; Johnsson, Stefan
; Dalaryd, Mårten
LU
and Knöös, Tommy
LU
- organization
- publishing date
- 2010
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- dosimetry, phantoms, Monte Carlo methods, radiation therapy
- in
- Medical Physics
- volume
- 37
- issue
- 3
- pages
- 1164 - 1168
- publisher
- American Association of Physicists in Medicine
- external identifiers
-
- wos:000275160300023
- pmid:20384253
- scopus:77749292384
- pmid:20384253
- ISSN
- 0094-2405
- DOI
- 10.1118/1.3314074
- language
- English
- LU publication?
- yes
- id
- 29cdd76c-10fa-47d3-a4b0-f04f3cf4c47c (old id 1595370)
- alternative location
- http://www.ncbi.nlm.nih.gov/pubmed/20384253?dopt=Abstract
- date added to LUP
- 2016-04-01 14:08:53
- date last changed
- 2022-03-21 22:28:01
@article{29cdd76c-10fa-47d3-a4b0-f04f3cf4c47c,
abstract = {{PURPOSE: In recent years, there has been an increasing interest in flattening-filter free (FFF) beams. However, since the removal of the flattening filter will affect both the mean and the variance of the energy spectrum, current beam-quality specifiers may not be adequate for reference dosimetry in such beams. The purpose of this work was to investigate an alternative, more general beam-quality specifier. METHODS: The beam-quality specifier used in this work was a combination of the kerma-weighted mean and the coefficient of variation of the linear attenuation coefficient in water. These parameters can in theory be determined from narrow-beam transmission measurements using a miniphantom "in-air," which is a measurement condition well suited also to small and nonstandard fields. The relation between the Spencer-Attix stopping-power ratios and this novel beam-quality specifier was described by a simple polynomial. For reference, the authors used Monte Carlo calculated spectra and stopping-power data for nine different beams, with and without flattening filter. RESULTS: The polynomial coefficients were obtained by least-squares optimization. For all beams included in this investigation, the average of the differences between the predicted and the Monte Carlo calculated stopping-power ratios was 0.02 +/- 0.17% (1 SD) (including TomoTherapy and CyberKnife example beams). CONCLUSIONS: An alternative dual-parameter beam-quality specifier was investigated. The evaluation suggests that it can be used successfully to predict stopping-power ratios in FFF as well as conventional beams, regardless of filtration.}},
author = {{Ceberg, Crister and Johnsson, Stefan and Dalaryd, Mårten and Knöös, Tommy}},
issn = {{0094-2405}},
keywords = {{dosimetry; phantoms; Monte Carlo methods; radiation therapy}},
language = {{eng}},
number = {{3}},
pages = {{1164--1168}},
publisher = {{American Association of Physicists in Medicine}},
series = {{Medical Physics}},
title = {{Prediction of stopping-power ratios in flattening-filter free beams.}},
url = {{https://lup.lub.lu.se/search/files/3815340/1691362.pdf}},
doi = {{10.1118/1.3314074}},
volume = {{37}},
year = {{2010}},
}