Small photon beam measurements using radiochromic film and Monte Carlo simulations in a water phantom

García‐Garduño, Olivia Amanda; Lárraga‐Gutiérrez, José M.; Rodríguez‐Villafuerte, M.; Martínez‐Dávalos, A.; Celis, Miguel Ángel

doi:10.1016/j.radonc.2010.03.016

Cited by 42 publications

(37 citation statements)

References 16 publications

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“…GafChromic EBT films were used as the benchmark due to their high spatial resolution and limited energy dependency. 31,32 Although EBT films have shown good agreement with Monte Carlo simulation 33,34 in small field dosimetry, van Battum et al 19 showed a standard deviation of 1.3% for EBT film dosimetry by averaging the data from two simultaneously irradiated films. Although this value was obtained for dose up to 2.3 Gy, it was also reported in the article that the scan uncertainty as a function of optical density (OD) remains small between 0.5 and 2.5.…”

Section: Discussionmentioning

confidence: 99%

Impact of the calculation resolution of AAA for small fields and RapidArc treatment plans

et al. 2011

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AAA10 improves the accuracy of dose calculations, and calculation grid of 1.0 mm is superior to using 2.5 mm, although calculation times increased by factor of 5. A suitable upper MU constraint should be assigned during optimization to avoid plans with high modulation. For plans with a relative high number of monitor units, calculations using 1 mm grid resolution are recommended. For planning target volume (PTV) which contains relatively large area of low density tissue, users should be aware of possible dose underestimation in the low density region and recalculation with AAA10 grid 1.0 mm is recommended.

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Section: Discussionmentioning

confidence: 99%

Impact of the calculation resolution of AAA for small fields and RapidArc treatment plans

et al. 2011

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“…Response of detectors in small fields and the determination of detector‐specific output correction factors have been extensively investigated for a range of detectors by several research groups, using one of the following three techniques: (a) empirical approach, where uncorrected signal ratios were determined and compared to the field output factors determined with reference detectors, (b) numerical approach, where

k_{Q_{italicclin}, Q_{italicref}}^{f_{italicclin}, f_{italicref}}

were determined with MC simulations, and (c) semi‐empirical approach which combines both, measurements and numerical/analytical calculations, and where

k_{Q_{italicclin}, Q_{italicref}}^{f_{italicclin}, f_{italicref}}

were the most commonly determined through the comparison of measured uncorrected detector's signal ratios with MC calculated field output factors . There are advantages and disadvantages of each of these approaches .…”

Section: Introductionmentioning

confidence: 99%

A novel method for the determination of field output factors and output correction factors for small static fields for six diodes and a microdiamond detector in megavoltage photon beams

et al. 2018

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Purpose The goal of this work is to provide a large and consistent set of data for detector‐specific output correction factors, kQitalicclin,Qitalicref0.166667emfitalicclin,fref, for small static fields for seven solid‐state detectors and to determine field output factors, ΩQitalicclin,Qitalicreffclin,fref, using EBT3 radiochromic films and W1 plastic scintillator as reference detectors on two different linear accelerators and four megavoltage photon beams. Consistent measurement conditions and recommendations given in the International Code of Practice TRS‐483 for small‐field dosimetry were followed throughout the study. Methods ΩQitalicclin,Qitalicreffclin,fref were determined on two linacs, Elekta Versa HD and Varian TrueBeam, for 6 and 10 MV beams with and without flattening filter and for nine fields ranging from 0.5 × 0.5 cm2 to 10 × 10 cm2. Signal readings obtained with EBT3 radiochromic films and W1 plastic scintillator were fitted by an analytical function. Volume averaging correction factors, determined from two‐dimensional (2D) dose matrices obtained with EBT3 films and fitted to bivariate Gaussian function, were used to correct measured signals. kQitalicclin,Qitalicreffclin,fref were determined empirically for six diodes, IBA SFD, IBA Razor, PTW 60008 P, PTW 60012 E, PTW 60018 SRS, and SN EDGE, and a PTW 60019 microDiamond detector. Results Field output factors and detector‐specific kQitalicclin,Qitalicreffclin,fref are presented in the form of analytical functions as well as in the form of discrete values. It is found that in general, for a given linac, small‐field output factors need to be determined for every combination of beam energy and filtration (WFF or FFF) and field size as the differences between them can be statistically significant (P < 0.05). For different beam energies, the present data for kQitalicclin,Qitalicreffclin,fref are found to differ significantly (P < 0.05) from the corresponding data published in TRS‐483 mostly for the smallest fields (<1.5 cm). For the PTW microDiamond detector, statistically significant differences (P < 0.05) between kQitalicclin,Qitalicreffclin,fref values were found for all investigated beams on an Elekta Versa HD linac for field sizes 0.5 × 0.5 cm2 and 0.8 × 0.8 cm2. Significant differences in kQitalicclin,Qitalicreffclin,fref between beams of a given energy but with and without flattening filters are found for measurements made in small fields (<1.5 cm) at a given linac. Differences in kQitalicclin,Qitalicreffclin,fref are also found when measurements are made at different linacs using the same beam energy filtration combination; for the PTW microDiamond detector, these differences were found to be around 6% and were considered as significant. Conclusions Selection of two reference detectors, EBT3 films and W1 plastic scintillator, and use of an analytical function, is a novel approach for the determination of ΩQitalicclin,Qitalicreffclin,fref for small static fields in megavoltage photon beams. Large set of kQitalicclin,Qitalicreffclin,fref data for s...

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“…An in-house [4] full MC previously developed and validated based on BEAMnrc and DOSEXYZnrc user codes was used in the commissioning and validation processes. Photon phase space files were generated for the same field sizes and their dose distributions in-air and water were calculated in the same conditions that measurements and TPS dose calculations.…”

Section: In-house Monte Carlo Simulationsmentioning

confidence: 99%

“…OAR, PDD, and TSF data acquisition were performed using the pinpoint chamber. For the smallest fields (6×6 and 12×12 mm 2 ), GafChromic EBT film (ISP, Corp., USA) was used to measure TSF [4]. Figure 1 shows a comparison of an in-air profile measured at isocenter (SSD=1000 mm) using different detectors.…”

Section: Detectorsmentioning

confidence: 99%

Commissioning and Validation of the First Monte Carlo Based Dose Calculation Algorithm Commercial Treatment Planning System in Mexico

Lárraga‐Gutiérrez¹,

García‐Garduño²,

Cruz³

et al. 2010

AIP Conference Proceedings

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Small photon beam measurements using radiochromic film and Monte Carlo simulations in a water phantom

Cited by 42 publications

References 16 publications

Impact of the calculation resolution of AAA for small fields and RapidArc treatment plans

Impact of the calculation resolution of AAA for small fields and RapidArc treatment plans

A novel method for the determination of field output factors and output correction factors for small static fields for six diodes and a microdiamond detector in megavoltage photon beams

Commissioning and Validation of the First Monte Carlo Based Dose Calculation Algorithm Commercial Treatment Planning System in Mexico

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