Evaluating Multi-Target Beam Setup Methods for LINAC-Based Stereotactic Treatment of Multiple Brain Metastases with...

Area of Science:

• Radiation Oncology
• Medical Physics

Background:

• Stereotactic radiotherapy (SRT) using LINAC-based, single-isocenter, non-coplanar techniques is effective for multiple brain metastases (BMs).
• Multi-target beam setup (MTBS) assigns individual beams to subsets of BMs within a single treatment plan.
• This study evaluates and compares various MTBS strategies for optimizing SRT plans.

Purpose of the Study:

• To evaluate and compare different multi-target beam setup (MTBS) strategies for LINAC-based stereotactic radiotherapy (SRT) of multiple brain metastases (BMs).
• To assess the impact of MTBS on plan quality parameters, including conformity and gradient indices, for plans with multiple dose prescriptions.
• To investigate the potential for automating MTBS to improve planning efficiency.

Main Methods:

• A planning study compared several MTBS strategies, including automated approaches, for non-coplanar SRT of multiple BMs.
• Individual dose prescriptions were assigned to each BM based on its volume.
• Adapted conformity and gradient indices were used to evaluate plan quality with multiple prescription doses.

Main Results:

• Distributing BMs across treatment beams significantly improved plan quality (2% CI, 9% GI, 15% V15Gy, 10% V5Gy) compared to using all beams for all BMs.
• No significant difference in plan quality was observed between different methods of distributing BMs.
• Increasing the number of treatment beams further improved plan quality but increased treatment time.

Conclusions:

• MTBS is crucial for enhancing the quality of non-coplanar LINAC-based SRT for multiple BMs with individual dose prescriptions.
• Automating MTBS can substantially reduce planning time for radiation oncology professionals.
• MTBS algorithms should incorporate restrictions on the number of generated beams to manage treatment duration effectively.