Calculation of beam quality correction factors for various thimble ionization chambers using the Monte Carlo code PENELOPE

Erazo, Fabián; Lallena, A. M.

doi:10.1016/j.ejmp.2012.01.001

Cited by 58 publications

(25 citation statements)

References 16 publications

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“…These new k Q values have also been compared with other Monte Carlo calculated values in the literature. [18][19][20]28 There is very good agreement between the different Monte Carlo calculations with differences typically less than 0.4%.…”

Section: A Basis Of Calculated K Q Factorsmentioning

confidence: 71%

Addendum to the AAPMˈs TG‐51 protocol for clinical reference dosimetry of high‐energy photon beams

et al. 2014

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An addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water in megavoltage photon beams is presented. This addendum continues the procedure laid out in TG-51 but new k Q data for photon beams, based on Monte Carlo simulations, are presented and recommendations are given to improve the accuracy and consistency of the protocol's implementation. The components of the uncertainty budget in determining absorbed dose to water at the reference point are introduced and the magnitude of each component discussed. Finally, the consistency of experimental determination of N D,w coefficients is discussed. It is expected that the implementation of this addendum will be straightforward, assuming that the user is already familiar with TG-51. The changes introduced by this report are generally minor, although new recommendations could result in procedural changes for individual users. It is expected that the effort on the medical physicist's part to implement this addendum will not be significant and could be done as part of the annual linac calibration.

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Section: A Basis Of Calculated K Q Factorsmentioning

confidence: 71%

Addendum to the AAPMˈs TG‐51 protocol for clinical reference dosimetry of high‐energy photon beams

et al. 2014

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“…Beam quality conversion factors, k Q , have been calculated in previous publications [4][5][6][8][9][10][11][12][13] as the ratio of Monte Carlo calculations of the absorbed dose to water, D w , to the absorbed dose to air in an ion chamber, D ch , in an electron beam with quality Q to that in cobalt-60…”

Section: A Beam Quality Conversion Factorsmentioning

confidence: 99%

“…3 There is current interest in updating clinical reference dosimetry protocols and recent publications have provided accurate measured and Monte Carlo calculated k Q factors, but results have mostly been obtained for photon beams. [4][5][6][7][8][9][10] A small number of publications [11][12][13] have focused on the determination of electron beam k Q factors but only for a few chamber types. Reference dosimetry protocols recommend the use of plane-parallel chambers for low-energy electron beams (E 0 < 10 MeV), but the stability of plane-parallel chamber calibrations have been shown to be questionable.…”

Section: Introductionmentioning

confidence: 99%

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Monte Carlo calculations of electron beam quality conversion factors for several ion chamber types

Muir

Rogers

2014

Medical Physics

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“…Within this framework, the RTNORM project is supporting the IAEA working group with experimental as well as Monte Carlo calculated

k_{Q, Q_{0}}

factors for different ionization chambers and beam qualities such as photons and protons. Whereas the use of Monte Carlo codes for the determination of

k_{Q, Q_{0}}

factors in high‐energy photon and electron beams has been extensively tested and is well established in the literature for the Monte Carlo codes egsnrc and penelope , data for protons are scarce with only one study by Gomà et al where penh was used to calculate

k_{Q, Q_{0}}

factors in clinical proton beams in agreement with experimental data within 1% or better. Furthermore, data for ions heavier than protons are nonexistent.…”

Section: Introductionmentioning

confidence: 99%

Comparison of penh, fluka, and Geant4/topas for absorbed dose calculations in air cavities representing ionization chambers in high‐energy photon and proton beams

et al. 2019

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Purpose The purpose of this work is to analyze whether the Monte Carlo codes penh, fluka, and geant4/topas are suitable to calculate absorbed doses and fQ/fQ0 ratios in therapeutic high‐energy photon and proton beams. Methods We used penh, fluka, geant4/topas, and egsnrc to calculate the absorbed dose to water in a reference water cavity and the absorbed dose to air in two air cavities representative of a plane‐parallel and a cylindrical ionization chamber in a 1.25 MeV photon beam and a 150 MeV proton beam — egsnrc was only used for the photon beam calculations. The physics and transport settings in each code were adjusted to simulate the particle transport as detailed as reasonably possible. From these absorbed doses, fQ0 factors, fQ factors, and fQ/fQ0 ratios (which are the basis of Monte Carlo calculated beam quality correction factors kQ,Q0) were calculated and compared between the codes. Additionally, we calculated the spectra of primary particles and secondary electrons in the reference water cavity, as well as the integrated depth–dose curve of 150 MeV protons in water. Results The absorbed doses agreed within 1.4% or better between the individual codes for both the photon and proton simulations. The fQ0 and fQ factors agreed within 0.5% or better for the individual codes for both beam qualities. The resulting fQ/fQ0 ratios for 150 MeV protons agreed within 0.7% or better. For the 1.25 MeV photon beam, the spectra of photons and secondary electrons agreed almost perfectly. For the 150 MeV proton simulation, we observed differences in the spectra of secondary protons whereas the spectra of primary protons and low‐energy delta electrons also agreed almost perfectly. The first 2 mm of the entrance channel of the 150 MeV proton Bragg curve agreed almost perfectly while for greater depths, the differences in the integrated dose were up to 1.5%. Conclusion penh, fluka, and geant4/topas are capable of calculating beam quality correction factors in proton beams. The differences in the fQ0 and fQ factors between the codes are 0.5% at maximum. The differences in the fQ/fQ0 ratios are 0.7% at maximum.

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Calculation of beam quality correction factors for various thimble ionization chambers using the Monte Carlo code PENELOPE

Cited by 58 publications

References 16 publications

Addendum to the AAPMˈs TG‐51 protocol for clinical reference dosimetry of high‐energy photon beams

Addendum to the AAPMˈs TG‐51 protocol for clinical reference dosimetry of high‐energy photon beams

Monte Carlo calculations of electron beam quality conversion factors for several ion chamber types

Comparison of penh, fluka, and Geant4/topas for absorbed dose calculations in air cavities representing ionization chambers in high‐energy photon and proton beams

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