To optimize the collimator angles in dual-arc volumetric modulated arc therapy (VMAT) plans for whole-brain radiotherapy with hippocampus and inner ear sparing (HIS-WBRT). Two sets of dual-arc VMAT plans were generated for 13 small-cell lung cancer patients: (1) The collimator angles of arcs 1 and 2 (θ₁/θ₂) were 350°/10°, 350°/30°, 350°/45°, 350°/60°, and 350°/80°, i.e., the intersection angle of θ₁ and θ₂ (Δθ) increased. (2) θ₁/θ₂ were 280°/10°, 300°/30°, 315°/45°, 330°/60°, and 350°/80°, i.e., Δθ = 90°. The conformity index (CI), homogeneity index (HI), monitor units (MUs), and dosimetric parameters of organs-at-risk were analyzed. Quality assurance for Δθ = 90° plans was performed. With Δθ increasing towards 90°, a significant improvement was observed for most parameters. In 350°/80° plans compared with 350°/10° ones, CI and HI were improved by 1.1% and 25.2%, respectively; MUs were reduced by 16.2%; minimum, maximum, and mean doses (D_100%, D_max, and D_mean, respectively) to the hippocampus were reduced by 5.5%, 6.3%, and 5.4%, respectively; D_mean to the inner ear and eye were reduced by 0.7% and 5.1%, respectively. With Δθ kept at 90°, the plan quality was not significantly affected by θ₁/θ₂ combinations. The gamma-index passing rates in 280°/10° and 350°/80° plans were relatively lower compared with the other Δθ = 90° plans. Δθ showed a significant effect on dual-arc VMAT plans for HIS-WBRT. With Δθ approaching 90°, the plan quality exhibited a nearly continuous improvement, whereas with Δθ = 90°, the effect of θ₁/θ₂ combination was insignificant.

优化双弧体积调制弧治疗 (VMAT) 计划中的准直器角度，用于海马和内耳保留全脑放射治疗 (HIS-WBRT)。13小细胞肺癌患者中产生两组双弧VMAT计划：弧1的（1）准直角度和2（θ ₁ / θ ₂）分别为350°/ 10°，350°/ 30°， 350°/45°、350°/60°和350°/80°，即θ ₁和θ ₂的交叉角(Δ θ )增加。（2）θ ₁ / θ ₂分别为280°/ 10°，300°/ 30°，315°/ 45°，330°/ 60°，和350°/ 80°，即，Δ θ  = 90°。从众指数（CI)、同质性指数 ( HI )、监测单位 (MU) 和危险器官的剂量学参数进行了分析。 执行了 Δ θ = 90° 计划的质量保证。与Δ θ朝向90°增大，观察到大多数参数的显著改善。350°/80°方案与350°/10°方案相比，CI和HI分别提高了1.1%和25.2%；MU 减少了 16.2%；海马体的最小、最大和平均剂量（分别为D _100%、D _max和D _mean）分别减少了 5.5%、6.3% 和 5.4%；D_均值对内耳和眼睛的影响分别减少了 0.7% 和 5.1%。Δ θ保持在 90° 时，计划质量不受θ ₁ / θ ₂组合的显着影响。与其他 Δ θ  = 90° 计划相比，280°/10° 和 350°/80° 计划的 gamma 指数通过率相对较低。Δ θ对 HIS-WBRT 的双弧 VMAT 计划有显着影响。与Δ θ接近90°时，计划质量表现出几乎不断改进，而用Δ θ  = 90°的效果，θ ₁ / θ ₂的组合不显着。