Purpose: To evaluate the impact of different aperture shape controller (ASC) stratification strategies on the dosimetric quality and treatment efficiency of HyperArc plans for intracranial oligometastases.
Methods: This retrospective study analyzed 17 patients with 1–3 intracranial oligometastases. For each patient, the HyperArc plans were reoptimized using six ASC strength settings (off, very low, low, moderate, high, and very high). Evaluations encompassed planning target volume (PTV) and organ at risk (OAR) dosimetric parameters (Paddick Conformity Index [Paddick CI], Gradient Index [GI], D2cm, OAR Dmax/Dmean, Gamma passing rate), and treatment efficiency parameters (monitor units [MUs], segment number [SN], Modulation Complexity Score [MCS], Average Leaf Trajectory [ALT], and aperture irregularity [AI]).
Results: No statistically significant differences were observed in the PTV and OAR dosimetric parameters or gamma passing rates among the ASC strategy groups (p > 0.05), indicating a minimal impact of the ASC on plan dosimetric quality. In addition, SN, MCS, and ALT demonstrated no significant intergroup differences (p > 0.05). However, AI improved with moderate and high ASC strength. Critically, the total MUs differed significantly among the groups (F = 2.904, p < 0.05), with high ASC strength causing significantly lower MUs than ASC-off (p < 0.05), suggesting enhanced treatment efficiency.
Conclusions: ASC stratification strategies do not significantly compromise plan dosimetric quality in HyperArc treatment for intracranial oligometastases; however, these can markedly optimize treatment efficiency, particularly by reducing MUs. Considering both plan complexity and treatment efficiency, a moderate or high ASC strength is recommended to maintain high-quality radiotherapy while improving workflow efficiency.
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2025 The Author(s). Precision Radiation Oncology published by John Wiley & Sons Australia, Ltd on behalf of Shandong Cancer Hospital & Institute.
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