Feasibility of implementing stereotactic body radiation therapy using a non-commercial volumetric modulated arc therapy treatment planning system for early stage lung cancer

Nearly 25% of patients diagnosed with early-stage non-small cell lung carcinomas (NSCLC) are medically inoperable. For these patients, the radial stereotactic body radiation therapy (SBRT), planned and delivered with intensity modulated radiation therapy (IMRT) techniques, offers the only curative option. However, IMRT-SBRT has three significant deficiencies: an elevated beam-on time (MU); a reduced MU-to-cGy coefficient; and a prolonged delivery time. To address these issues, we have developed our in-house version of volumetric modulated arc therapy (VMAT). In this preliminary study, we compared VMAT-SBRT with IMRT-SBRT in terms of optimization, dosimetry, and delivery. Our goal was to investigate the feasibility of replacing the exiting IMRT-SBRT with VMAT-SBRT as a safe and viable alternative radiation modality for early-stage NSCLC.