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Four-Dimensional Computed Tomography-Guided Valve Sizing for Transcatheter Pulmonary Valve Replacement
Published on: January 20, 2022
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Feasibility of 4D VMAT-CT.
Xiaodong Zhao1, Rui Zhang2,3
1Department of Radiation Oncology, Washington University in St. Louis, St. Louis, MO, United States of America.
Biomedical Physics & Engineering Express
|October 7, 2022
Summary
This study demonstrates the feasibility of four-dimensional VMAT-CT for accurate tracking during volumetric modulated arc therapy (VMAT) treatments involving respiratory motion. This method improves confidence and offers a viable solution for daily patient positioning and treatment monitoring.
Area of Science:
- Medical Physics
- Radiation Oncology
- Image-guided radiotherapy
Background:
- Previous work established the feasibility of 3D VMAT-CT tracking.
- 3D VMAT-CT is inadequate for treatments with significant respiratory motion.
- The need for improved tracking in dynamic VMAT treatments is critical.
Purpose of the Study:
- To reconstruct four-dimensional (4D) VMAT-CT.
- To evaluate the feasibility of tracking using 4D VMAT-CT.
- To compare 4D VMAT-CT tracking with 4D cone beam CT (CBCT).
Main Methods:
- Synchronized portal images and linac logs were sorted into four phases.
- 4D VMAT-CT+ was generated by fusing VMAT-CT and planning CT using registration.
- Dose was calculated per phase and registered for 4D dose reconstruction.
Main Results:
- 4D VMAT-CT+ tracking proved accurate and superior to 4D CBCT.
- The method detected phantom deformation and breathing pattern changes.
- Uncertainties had a minimal impact on tracking accuracy.
Conclusions:
- Accurate 4D VMAT-CT tracking is feasible for VMAT treatments with respiratory motion.
- This technique enhances VMAT confidence and provides clinical viability.
- It supports daily patient positioning, in vivo dosimetry, and treatment monitoring.
