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Figure 1 | Radiation Oncology

Figure 1

From: Multi-scenario based robust intensity-modulated proton therapy (IMPT) plans can account for set-up errors more effectively in terms of normal tissue sparing than planning target volume (PTV) based intensity-modulated photon plans in the head and neck region

Figure 1

Exposed body volumes. Body volumes exposed to doses higher than x% of the prescribed dose (Vbodyx%) in robust IMPT-plans assuming set-up errors of 0, 2, and 5 mm around the target volume derived from the original PTV through isotropic shrinkage by set-up margins of 0, 2, and 5 mm, respectively, for 7 patients with recurrent head and neck carcinomas and evaluated isodose levels x between 20% and 95%. The ratios of Vbodyx% in the 0 and 5 mm IMPT-plans (IMPT5mm and IMPT0mm, respectively) over Vbodyx% exposed in the 2 mm IMPT-plan (IMPT2mm) are displayed by red circles and green triangles, respectively. A significant decrease of −11.9 ± 0.8% in Vbodyx% in the robust IMPT5mm-plan was obtained in comparison with Vbodyx% exposed in the robust IMPT2mm-plan (p < 0.0001, F-Test). The respective increase in Vbodyx% in the IMPT0mm-plan was 6.2 ± 0.9% (p < 0.0001, F-Test).

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