Results of the two-way anova with repeated measures and interactions (p-values of pairwise tests for the measures of quality).

<p>Results of the two-way anova with repeated measures and interactions (p-values of pairwise tests for the measures of quality).</p

Results of the two-way anova with repeated measures and interactions (p-values of pairwise tests for the measures of quality).

<p>Results of the two-way anova with repeated measures and interactions (p-values of pairwise tests for the measures of quality).</p

Example dose distributions for the four plan scenarios (transverse slice).

<p>Example dose distributions for the four plan scenarios (transverse slice).</p

Results of the two-way anova with repeated measures and interactions (p-values of pairwise tests for monitor units, treatment times and scattered dose).

<p>Results of the two-way anova with repeated measures and interactions (p-values of pairwise tests for monitor units, treatment times and scattered dose).</p

mARC Treatment of Hypopharynx Carcinoma with Flat and Flattening-Filter-Free Beam Energies – A Planning Study

<div><p>Background</p><p>The recently implemented mARC-rotation-technique is capable to deliver high dose rate bursts. For the case of hypopharynx cancer plans we evaluate whether the mARC can achieve an advantage in treatment time in comparison to IMRT. These plans consider two arcs with flat and flattening filter free (FFF) beam energies.</p><p>Materials and Methods</p><p>For 8 hypopharynx-cancer patients step-and-shoot-IMRT and mARC plans were created retrospectively using flat and FFF beam energy. The comparison of the plan scenarios considered measures of quality for PTV coverage and sparing of organs at risk. All plans were irradiated on an anthromorphic phantom equipped with thermoluminescent dosimeters to measure scattered dose and treatment times.</p><p>Results</p><p>A visual comparison of the dose distribution did not show a marked preference for either technique or energy. The statistical evaluation yielded significant differences in favor of the mARC technique and the FFF energy. Scattered dose could be decreased markedly by the use of the mARC technique. Treatment times could be reduced up to 3 minutes with the use of mARC in comparison to IMRT. The high dose rate energy results in another time advantage of about 1 minute.</p><p>Conclusions</p><p>All four plan scenarios yielded equally good quality plans. A combination of the mARC technique with FFF 7 MV high dose rate resulted in a decrease of treatment times from about 9 minutes to 5–6 minutes in comparison to 6 MV IMRT.</p></div

Measures of quality for the four plan scenarios (mean values ± standard deviation and range).

<p>Measures of quality for the four plan scenarios (mean values ± standard deviation and range).</p

Example DVH (same patient as in Fig 2).

<p>Example DVH (same patient as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164616#pone.0164616.g002" target="_blank">Fig 2</a>).</p

Monitor units, treatment times and scattered dose for the four plan scenarios (mean values ± standard deviation and range).

<p>Monitor units, treatment times and scattered dose for the four plan scenarios (mean values ± standard deviation and range).</p

Schematic illustration of mARC delivery.

<p>Schematic illustration of mARC delivery.</p

Plan characteristics and IMRT inversion parameters for three different beam arrangements.

<p>Plan characteristics and IMRT inversion parameters for three different beam arrangements.</p