A new method for optimum dose distribution determination taking tumour mobility into account

Area of Science:

• Radiation Oncology
• Medical Physics
• Computational Biology

Background:

• External beam radiotherapy requires precise dose delivery.
• Tumor mobility presents a significant challenge in achieving optimal dose distribution.
• Enlarging target volumes can account for tumor motion but requires careful dose planning.

Purpose of the Study:

• To develop a method for determining optimal dose distribution in planning target volumes for mobile tumors.
• To ensure an acceptable tumor control probability (TCP) despite tumor dislocation.
• To account for tumor shifts modeled by a Gaussian distribution.

Main Methods:

• Introduction of a reduced (mean in ensemble) tumor cell density concept.
• Determination of target volume and dose distribution based on tumor mobility.
• Calculation of tumor control probability as a function of tumor shift.
• Monte Carlo simulation to analyze TCP distributions for varying mobility variances.

Main Results:

• The proposed method yields dose distributions independent of tumor mobility variance.
• TCP distributions remain consistent regardless of the degree of tumor movement.
• The planning target volume and dose distribution effectively compensate for tumor dislocation.

Conclusions:

• The developed method provides a robust approach to radiotherapy planning for mobile tumors.
• Optimal dose distribution can be achieved by accounting for tumor mobility statistics.
• The approach ensures reliable tumor control probability in the face of unpredictable tumor motion.