Dosimetric comparison of VMAT with integrated skin flash to 3D field-in-field tangents for left breast irradiation.

Dosimetric comparison of VMAT with integrated skin flash to 3D field-in-field tangents for left breast irradiation. J Appl Clin Med Phys. 2019 Jan 17;: Authors: Bogue J, Wan J, Lavey RS, Parsai EI Abstract Volumetric modulated arc therapy (VMAT) has been implemented for left breast irradiation to reduce prescription dose to the heart and improve dose homogeneity across the targeted breast. Our in-house method requires application of a bolus during the optimization process with a target outside of the body, then removing the bolus during the final calculation in order to incorporate skin flash in VMAT plans. To quantify the dosimetric trade-offs between traditional 3D field-in-field tangents and VMAT with integrated skin flash for these patients, we compared nine consecutive patients who recently received radiation to their entire left breast but not their regional lymphatics. Tangent plans used non-divergent tangents of mixed energies and VMAT plans utilized four 6 MV arcs of roughly 260°. Mean dose to the heart, contralateral lung, and contralateral breast and their volume receiving 5%, 10%, and 20% of the prescription dose were higher in all nine VMAT plans than in the static tangential beam plans. For all critical structures, the mean VMAT DVH was higher in the low-dose region and crossed the 3D field-in-field DVH between 23.13% and 34.18% of the prescription dose (984.75-1454.70 cGy). However, the volume of the contralateral br...
Source: Journal of Applied Clinical Medical Physics - Category: Physics Authors: Tags: J Appl Clin Med Phys Source Type: research