Effects of gas-filled temporary breast tissue expanders on radiation dose from modulated rotational photon beams

Gas-filled temporary tissue expanders (TTEs), implanted to assist in post mastectomy breast reconstructions, are expected produce increased dosimetric uncertainty radiotherapy treatments, due their containing both a substantial metallic component and comparatively large volume of gas. This study therefore builds on previous investigations the effects gas-filled TTEs static photon electron beams, by examining these implants dose distributions from common modulated rotational treatment techniques; volumetric arc therapy (VMAT) helical tomotherapy (HT). Radiochromic film measurements were used evaluate accuracy VMAT HT calculations, for humanoid phantom augmented with sample Aeroform CO2-filled TTE (AirXpanders Inc, San Jose, USA) as well purpose-designed 3D printed tissue. Results showed that TomoTherapy Hi-Art VoLO convolution-superposition algorithm (Accuray Sunnyvale, produced accurate calculations within this complex phantom, including immediately anterior posterior TTE. The Varian Eclipse Acuros (AXB) generally better agreement measurement than AAA (Varian Medical Systems, Palo Alto, USA), although regions 5% 10% disagreement AXB dosimetrically-challenging region side implant. Although has obvious downstream beam, results how inverse-planning treatments can fluence compensate dramatic density heterogeneities Despite some disagreements planned dose, all use inverse-planned beams resulted homogeneous coverage target, patient-like Due importance matching each distribution TTE, careful available imaging techniques is advisable, when delivered patients TTEs.