title: Bilateral Breast Irradiation Using Hybrid Volumetric Modulated Arc Therapy (h-VMAT) Technique: A Planning Case Report.
abstract: The purpose of this planning case report is to share the perceived dosimetric benefits of innovative hybrid volumetric modulated arc therapy (h-VMAT) for bilateral breast cancer radiotherapy in two patients with synchronous bilateral breast cancer. Two patients with early bilateral breast cancer after breast conservation surgery and adjuvant chemotherapy were planned for bilateral breast radiotherapy. On the planning computed tomography (CT) dataset, bilateral breast planning treatment volume (PTV) and organs at risk (OARs) were delineated using standard guidelines. Using the same structure set, volumetric modulated arc therapy (VMAT) and h-VMAT plans were generated and compared dosimetrically. The h-VMAT showed comparable target coverage, conformity and homogeneity while sparing of both lungs and heart were better. The dose to heart was reduced with h-VMAT, with a V25Gyand V5Gyof 3.2 & 22.3% for h-VMAT versus 11.6 & 84.9% for the VMAT plan. Similarly, the dose to the total lung was better in h-VMAT with a V20Gyand V5Gyof 12.1 & 46.2 versus 19.9 & 83.3% for VMAT. Overall the results indicate a better sparing of lung and heart at low doses with h-VMAT. Long-term clinical follow-up will give us more insight about the dosimetric benefits of these innovative techniques.
authors.affiliation: Department of Radiation Oncology, Global Hospitals, Chennai.
authors.forename: Sitaraman
authors.initials: S
authors.lastname: Balaji Subramanian
authors.affiliation: Department of Radiation Oncology, Global Hospitals, Chennai.
authors.forename: Karunakaran
authors.initials: K
authors.lastname: Balaji
authors.affiliation: Department of Radiation Oncology, Global Hospitals, Chennai.
authors.forename: Moorthi
authors.initials: M
authors.lastname: Thirunavukarasu
authors.affiliation: Department of Radiation Oncology, Global Hospitals, Chennai.
authors.forename: Sumana
authors.initials: S
authors.lastname: Premkumar
keywords: bilateral breast cancer; hybrid vmat; vmat