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The Stanford Volumetric Modulated Arc Therapy Total Body Irradiation Technique
Nataliya Kovalchuk1, Eric Simiele1, Lawrie Skinner1
1Department of Radiation Oncology, Stanford University, Stanford, California.
Practical Radiation Oncology
|February 19, 2022
Summary
The Stanford volumetric modulated arc therapy (VMAT) total body irradiation (TBI) technique offers effective organ sparing and precise dose delivery. This method may facilitate wider adoption and multi-institutional studies for advanced radiation therapy.
Area of Science:
- Radiation Oncology
- Medical Physics
Background:
- Total body irradiation (TBI) is a critical component of hematopoietic stem cell transplantation.
- Volumetric modulated arc therapy (VMAT) offers potential advantages in dose conformity and sparing of organs at risk compared to traditional TBI techniques.
Purpose of the Study:
- To describe the technical aspects of the Stanford VMAT-TBI technique.
- To compare the Stanford VMAT-TBI technique with other VMAT-TBI methods.
- To share initial clinical experience and outcomes.
Main Methods:
- 35 patients treated with VMAT-TBI from September 2019 to August 2021.
- Automated planning scripts used for treatment planning.
- Organ doses (lungs, kidneys, lenses, gonads, brain, thyroid) were optimized based on regimen.
- Quality assurance included portal dosimetry and Mobius3D; robustness evaluated with isocenter shifts.
- Image-guided radiation therapy and in vivo measurements were performed.
Main Results:
- Consistent sparing of lungs (Dmean 57.6% ± 4.4%) and kidneys (Dmean 70.0% ± 9.9%).
- Effective gonadal sparing (Dmean 0.69 ± 0.13 Gy) achieved for patients with benign disease.
- High average Gamma passing rate (98.1% ± 1.6%) and reproducible patient setup.
- Robustness evaluation showed insensitivity to small positioning deviations.
Conclusions:
- The Stanford VMAT-TBI technique is technically feasible and effective.
- The technique allows for significant organ sparing and precise dose delivery.
- Shared autoplanning scripts may promote wider adoption and multi-institutional research.