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Adaptive fractionation therapy: II. Biological effective dose
Mingli Chen1, Weiguo Lu, Quan Chen
1TomoTherapy Inc, 1240 Deming Way, Madison, WI 53717, USA.
Physics in Medicine and Biology
|September 11, 2008
Summary
Adaptive radiation therapy uses biological effective dose (BED) to adjust fraction sizes based on organ at risk (OAR) and tumor proximity. This method optimizes treatment by maximizing OAR survival and tumor cell kill, outperforming conventional fractionation.
Area of Science:
- Radiation oncology
- Medical physics
- Biophysics
Background:
- Radiation therapy fractionation aims to maximize tumor cell kill while sparing organs at risk (OAR).
- Conventional fractionation uses fixed dose per fraction, irrespective of daily OAR-tumor positional variations.
- Adaptive fractionation offers a potential improvement by adjusting treatment based on real-time anatomical changes.
Purpose of the Study:
- To develop and validate an adaptive fractionation strategy based on biological effective dose (BED).
- To create a lookup table for determining fraction sizes dynamically during radiation therapy.
- To maximize organ at risk (OAR) survival and preserve tumor cell kill using adaptive fractionation.
Main Methods:
- Developed a lookup table using mathematical induction to guide fraction size selection.
- Calculated fraction sizes based on remaining tumor BED, OAR/tumor dose ratio, and remaining fractions.
- Utilized daily setup images to determine OAR-tumor configuration and dose ratio before each fraction.
Main Results:
- The proposed adaptive fractionation method demonstrated effectiveness in simulations.
- The lookup table successfully determined optimal fraction sizes based on dynamic OAR-tumor configurations.
- The strategy effectively balanced OAR sparing and tumor control compared to conventional methods.
Conclusions:
- Adaptive fractionation based on BED and real-time OAR-tumor configuration is a viable strategy.
- This approach allows for personalized radiation therapy, optimizing dose delivery fraction by fraction.
- The lookup table method provides an efficient way to implement adaptive fractionation in clinical practice.
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