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Dose compensation based on biological effectiveness due to interruption time for photon radiation therapy
Daisuke Kawahara1, Hisashi Nakano2, Akito Saito1
1Department of Radiation Oncology, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Hiroshima 734-8551, Japan.
The British Journal of Radiology
|May 2, 2020
Summary
Radiation therapy interruptions reduce biological effectiveness. A new dose compensation method is proposed to correct for this decrease, ensuring treatment efficacy during photon radiation therapy.
Area of Science:
- Radiation Oncology
- Medical Physics
- Radiobiology
Background:
- Radiation therapy interruptions can lead to sublethal damage repair.
- This repair can decrease the overall biological effectiveness of the treatment.
- Accurate dose delivery is crucial for effective cancer treatment.
Purpose of the Study:
- To evaluate the impact of interruption time on the biological effectiveness of photon radiation therapy.
- To develop and propose a dose compensation method to counteract the loss of biological effectiveness during treatment interruptions.
Main Methods:
- Monte Carlo simulations were used to calculate lineal energy distribution in human salivary gland tumors.
- The microdosimetric kinetic model estimated biological dose (Dbio).
- A dose compensating factor was derived based on interruption time (τ) and dose per fraction.
Main Results:
- A loss of biological effectiveness (Δ) was observed, particularly when interruptions occurred mid-dose.
- Significant Δ (>3%) occurred for τ ≥ 10-20 min, depending on the dose per fraction.
- The dose compensating factor increased with higher dose per fraction and dose rates.
Conclusions:
- Interruption in photon radiotherapy leads to a reduction in biological effectiveness due to sublethal damage repair.
- The proposed dose compensation method effectively corrects for the decrease in biological effectiveness caused by treatment interruptions.
- This method helps maintain treatment efficacy by adjusting for unexpected changes in biological effect.
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