Novel DCAT plans in stereotactic body radiotherapy for stage I/II centrally located non-small-cell lung cancer

This study evaluated the feasibility of a novel dynamic conformal arc therapy (DCAT) plan, based on segment shape optimization (SSO) and variable dose rate (VDR), versus volumetric modulated arc therapy (VMAT) for stereotactic body radiotherapy (SBRT) in stage I/II centrally located non-small-cell lung cancer (NSCLC) per RTOG 0813. Twenty-five patients with PTV < 70 cc were retrospectively analyzed, with both plans using identical parameters in Monaco. Both plans met RTOG 0813 criteria. DCAT showed increased ipsilateral and total lung dose but no significant differences in most other organs at risk (OARs) (P > 0.05). DCAT significantly reduced segments (median 19.38%), monitor units (MUs, median 23.27%), and beam-on time (BOT, median 8.80 s; P < 0.05). Its γ passing rate (2%, 1 mm) was higher (93.70% vs. VMAT 91.90%, P < 0.05). Larger PTV volumes improved DCAT's heterogeneity index (HI) and segment advantages but worsened R_50% vs. VMAT. Novel DCAT is feasible for SBRT in such NSCLC, especially with small PTV, offering shorter BOT, higher delivery accuracy, and comparable OARs sparing to VMAT.