Intensity-modulated proton therapy (IMPT) planning for the head and neck (HN) cancer often requires the use of the range shifter, which can increase the lateral penumbrae of the pencil proton beam in the patient, thus leading to an increase in unnecessary dose to the organs at risks (OARs) in proximity to the target volumes. The primary goal of the current study was to investigate the dosimetric benefits of utilizing beam-specific apertures for the IMPT HN cancer plans. The current retrospective study included computed tomography datasets of 10 unilateral HN cancer patients. The clinical target volume (CTV) was divided into low-risk CTV1 and high-risk CTV2. Total dose prescriptions to the CTV1 and CTV2 were 54 Gy(RBE) and 70 Gy(RBE), respectively, with a fractional dose of 2 Gy(RBE). All treatment plans were robustly optimized (patient setup uncertainty = 3 mm; range uncertainty = 3.5%) on the CTVs. For each patient, 2 sets of plans were generated: (1) without beam-specific aperture (WOBSA), and (2) with beam-specific aperture (WBSA). Specifically, both the WOBSA and WBSA of the given patient used identical beam angles, air gap, optimization structures, optimization constraints, and optimization settings. Target coverage and homogeneity index were comparable in both the WOBSA and WBSA plans with no statistical significance (p > 0.05). On average, the mean dose in WBSA plans was reduced by 12.1%, 2.9%, 3.0%, 3.8%, and 5.2% for the larynx, oral cavity, parotids, superior pharyngeal constrictor muscle, and inferior pharyngeal constrictor muscle, respectively. The dosimetric results of the OARs were found to be statistically significant (p < 0.05). The use of the beam-specific apertures did not deteriorate the coverage and homogeneity in the target volume and allowed for a reduction in mean dose to the OARs with an average difference up to 12.1%.

头颈部 (HN) 癌症的强度调制质子治疗 (IMPT) 计划通常需要使用范围移位器，这会增加患者笔形质子束的横向半影，从而导致不必要的剂量增加到目标体积附近的危险器官 (OAR)。当前研究的主要目标是调查将光束特定孔径用于 IMPT HN 癌症计划的剂量学优势。当前的回顾性研究包括 10 名单侧 HN 癌症患者的计算机断层扫描数据集。临床靶区（CTV）分为低危CTV1和高危CTV2。CTV1 和 CTV2 的总剂量处方分别为 54 Gy(RBE) 和 70 Gy(RBE)，部分剂量为 2 Gy(RBE)。所有治疗计划都在 CTV 上进行了稳健优化（患者设置不确定性 = 3 毫米；范围不确定性 = 3.5%）。对于每个患者，生成了 2 组计划：(1) 没有光束特定孔径 (WOBSA)，和 (2) 具有光束特定孔径 (WBSA)。具体而言，给定患者的 WOBSA 和 WBSA 均使用相同的光束角、气隙、优化结构、优化约束和优化设置。WOBSA 和 WBSA 计划的目标覆盖率和同质性指数具有可比性，没有统计学意义（优化结构、优化约束和优化设置。WOBSA 和 WBSA 计划的目标覆盖率和同质性指数具有可比性，没有统计学意义（优化结构、优化约束和优化设置。WOBSA 和 WBSA 计划的目标覆盖率和同质性指数具有可比性，没有统计学意义（p > 0.05）。平均而言，WBSA 计划中喉部、口腔、腮腺、咽上缩肌和咽下缩肌的平均剂量分别降低了 12.1%、2.9%、3.0%、3.8% 和 5.2%。发现 OAR 的剂量测定结果具有统计学意义 ( p < 0.05)。使用波束特定孔径不会降低目标体积的覆盖范围和均匀性，并允许 OAR 的平均剂量降低，平均差异高达 12.1%。