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Updated: Mar 5, 2026
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Treatment of Liver Metastases Using an Internal Target Volume Method for Stereotactic Body Radiotherapy
Published on: May 8, 2018
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VMAT plus a few computer-optimized non-coplanar IMRT beams (VMAT+) tested for liver SBRT
Abdul Wahab M Sharfo1, Maarten L P Dirkx1, Sebastiaan Breedveld1
1Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam, The Netherlands.
Summary
A new radiation therapy technique, VMAT+, offers improved organ sparing and dose control for liver SBRT compared to standard VMAT. It achieves similar tumor dose coverage as complex non-coplanar treatments with only a small increase in delivery time.
Area of Science:
- Radiation Oncology
- Medical Physics
- Cancer Treatment
Background:
- Stereotactic Body Radiation Therapy (SBRT) is a key treatment for liver metastases.
- Volumetric Modulated Arc Therapy (VMAT) is a common SBRT technique.
- Optimizing dose coverage and organ-at-risk (OAR) sparing remains a challenge in liver SBRT.
Purpose of the Study:
- To introduce and evaluate VMAT+, a novel approach combining VMAT with a limited number of non-coplanar IMRT beams.
- To compare VMAT+ against coplanar VMAT and multi-beam non-coplanar treatments for liver SBRT.
- To assess the feasibility of VMAT+ for delivering high tumor doses while minimizing OAR exposure.
Main Methods:
- VMAT+ plans were created for 15 liver metastasis patients.
- Plans were compared to dual-arc VMAT and 25-beam non-coplanar (25-NCP) plans.
- Evaluated parameters included tumor Biologically Effective Dose (BED), OAR doses, dose spillage, compactness, and delivery time.
Main Results:
- VMAT+ achieved tumor BED equivalent to 25-NCP, surpassing standard VMAT in 5 patients.
- VMAT+ demonstrated significant improvements in OAR sparing, intermediate-dose spillage, and dose compactness compared to VMAT.
- Treatment time increased by only 4.1 minutes for VMAT+ over VMAT, while 25-NCP was significantly longer.
Conclusions:
- VMAT+ is an effective liver SBRT strategy, matching advanced non-coplanar techniques in tumor dose delivery.
- VMAT+ offers superior OAR sparing and dose distribution compared to standard VMAT.
- The proposed VMAT+ technique provides a favorable balance between treatment efficacy and delivery efficiency.
