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An on-line replanning scheme for interfractional variations.
Ergun E Ahunbay1, Cheng Peng, Guang-Pei Chen
1Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
Medical Physics
|September 10, 2008
Summary
A new online adaptive replanning strategy using segment aperture morphing (SAM) and segment weight optimization (SWO) allows for rapid adjustments in radiation therapy. This method corrects for anatomical changes in real-time, matching the effectiveness of full reoptimization within minutes.
Area of Science:
- Radiation Oncology
- Medical Physics
- Image-Guided Therapy
Background:
- Online adaptive replanning is crucial for correcting interfraction anatomic changes in radiation therapy.
- Current full replanning techniques are too time-consuming for practical clinical implementation.
Purpose of the Study:
- To present a novel, rapid online replanning strategy for real-time correction of interfraction anatomic changes.
- To evaluate the efficacy and speed of the proposed SAM-SWO scheme.
Main Methods:
- A three-step process: semiautomatic contour delineation, online segment aperture morphing (SAM), and optional segment weight optimization (SWO).
- The scheme was tested on direct-aperture-based intensity-modulated radiation therapy (IMRT) for prostate and abdomen cases.
Main Results:
- The SAM-SWO scheme achieved dose-volume histograms comparable to full reoptimization.
- SAM alone sufficed for minor deformations; SAM and SWO were needed for significant deformations.
- Both SAM and SWO completed within 1 minute, with the overall process under 10 minutes.
Conclusions:
- The SAM-SWO scheme offers a practical and rapid alternative to full replanning for online adaptive radiotherapy.
- This approach enables dose-guided radiotherapy by efficiently adapting to daily anatomical variations.
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