324 Monte Carlo correction factors in non reference conditions: buildup regions of a 6MV photon beam

Peña, J.; Sánchez‐Doblado, F.; Capote-Noy, Roberto; Terrón, J.A.; Gómez, F.

doi:10.1016/s0167-8140(05)81300-3

Cited by 2 publications

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“…This is most likely due to the influence of the PinPoint chamber itself in the beam. Pena et al (2006) calculated the correction factors by implementing the chamber geometry of a Farmer chamber. As this is out of the scope of the subject of this paper, this will be a topic in further research.…”

Section: Validation Of the Treatment Head And ML Mmlc Mc Componentmentioning

confidence: 99%

Monte Carlo modeling of the ModuLeaf miniature MLC for small field dosimetry and quality assurance of the clinical treatment planning system

et al. 2007

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The purpose of this investigation was the verification of both the measured data and quality of the implementation of the add-on ModuLeaf miniature multileaf collimator (ML mMLC) into the clinical treatment planning system for conformal stereotactic radiosurgery treatment. To this end the treatment head with ML mMLC was modeled in the BEAMnrc Monte Carlo (MC) code. The 6 MV photon beams used in the setup were first benchmarked with a set of measurements. A total ML mMLC transmission of 1.13% of the 10 x 10 cm2 open field dose was measured and reproduced with the BEAMnrc/DOSXYZnrc code. Correspondence between calculated and measured output factors (OFs) was within 2%. Correspondence between MC and measured profiles was within 2% dose and 2 mm distance, only for the smallest 0.5 x 0.5 cm2 field the results were within 3% dose. In the next step, the MC model was compared with Gafchromic film measurements and Pinnacle(3) 7.4 f (convolution superposition algorithm) calculated dose distributions, using a gamma evaluation comparison, for a multi-beam patient setup delivered to a Lucytrade mark phantom. The gamma evaluation of the MC versus Gafchromic film resulted in 3.4% of points not fulfilling gamma

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Section: Validation Of the Treatment Head And ML Mmlc Mc Componentmentioning

confidence: 99%

Monte Carlo modeling of the ModuLeaf miniature MLC for small field dosimetry and quality assurance of the clinical treatment planning system

et al. 2007

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“…This explanation was also confirmed by Swanpalmer and Johansson (2011) and Legrand et al (2012) in 60 Co beams. Moreover, Legrand et al (2012) and Pena et al (2006) found a depth dependence of the displacement effect.…”

Section: Introductionmentioning

confidence: 92%

Experimental determination of the effective point of measurement and the displacement correction factor for cylindrical ionization chambers in a 6 MV photon beam

2012

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The displacement effect of cylindrical ionization chambers is taken into account either by an effective point of measurement (EPOM) or, alternatively, by using a displacement correction factor. The dependence of these effects on water was examined as a function of the cavity radius for (60)Co gamma radiation in a previous paper. This paper describes results for high-energy photon beams using the same measurement technique. Additionally, the displacement correction factor was directly measured. Absorbed doses measured under reference conditions following the international protocol IAEA TRS-398 and the German protocol DIN 6800-2 agreed well between the chambers with different cavity radii within a standard uncertainty of 0.2%. However, there was a constant difference of 0.2% between both protocols. Similar to our observations made in (60)Co, absorbed doses measured with the different chambers at depths beyond the maximum showed deviations of up to 0.6% and 0.5% for IAEA TRS-398 and DIN 6800-2, respectively, and deviations of more than 1% were found for both protocols in the build-up and maximum region. We therefore propose modified formulas for the determination of the EPOM and the displacement correction factor.

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324 Monte Carlo correction factors in non reference conditions: buildup regions of a 6MV photon beam

Cited by 2 publications

References 0 publications

Monte Carlo modeling of the ModuLeaf miniature MLC for small field dosimetry and quality assurance of the clinical treatment planning system

Monte Carlo modeling of the ModuLeaf miniature MLC for small field dosimetry and quality assurance of the clinical treatment planning system

Experimental determination of the effective point of measurement and the displacement correction factor for cylindrical ionization chambers in a 6 MV photon beam

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