Effects of Institutional Experience on Plan Quality in Stereotactic Radiotherapy Using HyperArc for Brain Metastases

Area of Science:

• Radiation Oncology
• Medical Physics
• Neurosurgery

Background:

• HyperArc (HA) is an automated technique for single-isocenter brain stereotactic radiotherapy (SRT).
• Planner expertise may influence dosimetric outcomes in automated radiotherapy planning.
• Assessing institutional experience is crucial for optimizing HA-SRT quality.

Purpose of the Study:

• To evaluate the impact of institutional experience on HA-SRT plan quality.
• To compare dosimetric outcomes for single and multiple brain metastases treated with HA-SRT.
• To determine if accumulated experience improves treatment efficacy and safety.

Main Methods:

• Retrospective analysis of 20 patients with single metastases and 40 with multiple metastases treated with HA-SRT.
• Patients were divided into earlier (2020-2021/2020-2022) and later (2022-2024) treatment groups.
• Key dosimetric parameters including GTV doses, normal brain volumes, HI, GI, and MU were compared using linear regression.

Main Results:

• The later treatment group demonstrated significantly higher D98% and Dmean for GTV in both single and multiple metastases.
• Normal brain V25Gy, V30Gy, and GI mean values remained comparable between groups.
• Mean HI and total MU significantly increased in the later group, with significant interaction between PTV volume and treatment era.

Conclusions:

• Accumulated institutional experience led to enhanced dosimetric outcomes in HA-SRT.
• Improved GTV coverage and brain dose sparing were observed with increased experience.
• Institutional learning is vital for maximizing plan quality in automated SRT techniques like HyperArc.