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Radiation Planning Assistant - A Streamlined, Fully Automated Radiotherapy Treatment Planning System
Published on: April 11, 2018
Motion-weighted target volume and dose-volume histogram: a practical approximation of four-dimensional planning and
Geoffrey Zhang1, Vladimir Feygelman, Tzung-Chi Huang
1Division of Radiation Oncology, Moffitt Cancer Center, Tampa, FL 33612, USA.
Summary
A new motion-weighted approach improves 3D radiotherapy planning by incorporating 4D-CT data. This method, using motion-weighted CTV (mwCTV) and motion-weighted DVH (mwDVH), better approximates 4D-dose accumulation without complex deformable image registration.
Area of Science:
- Medical Physics
- Radiation Oncology
- Image-Guided Therapy
Background:
- Current 3D image-guided brachytherapy (IGBT) planning does not utilize respiratory motion information.
- This limits the accuracy of dose delivery and evaluation.
Purpose of the Study:
- To introduce a novel motion-weighted contour volume (mwCTV) delineation method for ITV-based 3D planning.
- To incorporate 4D-CT information into 3D planning for improved accuracy.
Main Methods:
- Incorporated occupancy information from 4D-CT contours into mwCTV generation.
- Applied occupancy-weighting for plan optimization and generated motion-weighted DVHs (mwDVHs).
- Compared mwDVHs with DVHs from deformable image registration (DIR)-based 4D-dose accumulation and standard 3D methods in 10 cases.
Main Results:
- mwDVH curves closely approximated 4D-dose accumulation DVHs, outperforming standard 3D methods.
- The 70 Gy-covered CTV volume difference between mwDVH and 4D methods was minimal (0.3% ± 0.7%).
- Mean RMS difference for 4D-mwDVH was significantly lower (0.4 ± 0.3) than for 4D-3D (1.7 ± 1.1).
Conclusions:
- The mwCTV and mwDVH method offers a practical and simple approximation of 4D-dose accumulation.
- This approach enhances 3D planning accuracy without requiring complex DIR techniques.
- It facilitates more accurate dose evaluation in radiotherapy planning.
