@Article{Hofbauer2016,
journal="Journal of Contemporary Brachytherapy",
issn="1689-832X",
volume="8",
number="2",
year="2016",
title="Impact of heterogeneity-corrected dose calculation using a grid-based Boltzmann solver on breast and cervix cancer brachytherapy",
abstract=" Purpose : To analyze the impact of heterogeneity-corrected dose calculation on dosimetric quality parameters in gyne¬cological and breast brachytherapy using Acuros, a grid-based Boltzmann equation solver (GBBS), and to evaluate the shielding effects of different cervix brachytherapy applicators.    Material and methods:   Calculations with TG-43 and Acuros were based on computed tomography (CT) retrospectively, for 10 cases of accelerated partial breast irradiation and 9 cervix cancer cases treated with tandem-ring applicators. Phantom CT-scans of different applicators (plastic and titanium) were acquired. For breast cases the V<sub<20Gyαβ3  to lung, the D 0.1cm³ , D 1cm³ , D 2cm³  to rib, the D 0.1cm³ , D 1cm³ , D 10cm³  to skin, and D max  for all structures were reported. For cervix cases, the D 0.1cm³ , D 2cm³  to bladder, rectum and sigmoid, and the D 50 , D 90 , D 98 , V 100  for the CTV HR  were reported. For the phantom study, surrogates for target and organ at risk were created for a similar dose volume histogram (DVH) analysis. Absorbed dose and equivalent dose to 2 Gy fractionation (EQD2) were used for comparison.    Results : Calculations with TG-43 overestimated the dose for all dosimetric indices investigated. For breast, a decrease of ~8% was found for D 10cm³  to the skin and 5% for D 2cm³  to rib, resulting in a difference ~ –1.5 Gy EQD2 for overall treatment. Smaller effects were found for cervix cases with the plastic applicator, with up to –2% (–0.2 Gy EQD2) per fraction for organs at risk and –0.5% (–0.3 Gy EQD2) per fraction for CTV HR . The shielding effect of the titanium applicator resulted in a decrease of 2% for D 2cm³  to the organ at risk versus 0.7% for plastic.    Conclusions : Lower doses were reported when calculating with Acuros compared to TG-43. Differences in dose parameters were larger in breast cases. A lower impact on clinical dose parameters was found for the cervix cases. Applicator material causes systematic shielding effects that can be taken into account.",
author="Hofbauer, Julia
and Kirisits, Christian
and Resch, Alexandra
and Xu, Yingjie
and Sturdza, Alina
and Pötter, Richard
and Nesvacil, Nicole",
pages="143--149",
doi="10.5114/jcb.2016.59352",
url="http://dx.doi.org/10.5114/jcb.2016.59352"
}