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Updated: Jun 3, 2026
08:54
Treatment of Liver Metastases Using an Internal Target Volume Method for Stereotactic Body Radiotherapy
Published on: May 8, 2018
Choreographing couch and collimator in volumetric modulated arc therapy
Yingli Yang1, Pengpeng Zhang, Laura Happersett
1Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
Summary
Optimized trajectory-based volumetric modulated arc therapy (VMAT) improves dose delivery for central nervous system (CNS) tumors. This advanced VMAT technique offers better target coverage and reduced organ-at-risk radiation exposure, enhancing treatment efficiency.
Area of Science:
- Radiation Oncology
- Medical Physics
- Neurosurgery
Background:
- Volumetric Modulated Arc Therapy (VMAT) is a modern radiotherapy technique.
- Treating Central Nervous System (CNS) tumors requires precise radiation delivery to minimize damage to critical structures.
- Optimizing beam trajectories is crucial for enhancing VMAT efficacy and safety.
Purpose of the Study:
- To design and optimize noncoplanar subarcs for VMAT on both Varian TrueBEAM and traditional accelerators.
- To investigate the dosimetric advantages of trajectory-based VMAT for CNS tumor treatment.
Main Methods:
- A score function guided the selection of simultaneous couch, gantry, and collimator motion for beam trajectories.
- Hierarchical clustering grouped beam orientations into continuous subarcs, considering mechanical limitations.
- Principal component analysis and an in-house VMAT algorithm optimized multileaf collimator positions and monitor units.
Main Results:
- Trajectory-based VMAT (Tra-VMAT) improved target dose conformality compared to standard VMAT (Std-VMAT).
- Tra-VMAT significantly reduced maximum doses to organs at risk like the brainstem and optic nerves.
- Tra-VMAT demonstrated improved planning target volume dose and reduced cochlea doses compared to intensity-modulated radiotherapy (IMRT), with comparable or reduced beam-on time.
Conclusions:
- Optimized couch, gantry, and collimator trajectories enhance VMAT's mechanical flexibility.
- This approach offers superior dosimetric properties for CNS tumor treatment.
- Trajectory-based VMAT presents an improved and more efficient treatment option for CNS tumors.
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