An energy-conserving dose summation method for dose accumulation in radiotherapy

Area of Science:

• Medical Physics
• Radiotherapy
• Medical Imaging

Background:

• Radiation therapy dose accumulation is crucial for treatment evaluation but can be inaccurate due to patient mass changes.
• Existing methods may not precisely reflect total deposited energy when body mass fluctuates during treatment.

Purpose of the Study:

• To introduce an energy-conserving dose summation method for calculating total dose in patients with changing body mass.
• To ensure accurate characterization of treatment input in adaptive radiotherapy.

Main Methods:

• A novel energy and mass-conserving dose reconstruction technique was developed.
• Dose and mass data were transferred from dosimetry images to a reference image.
• A mass-weighted (MW) total dose was calculated by adjusting transferred doses based on mass ratios.

Main Results:

• The MW total dose accurately represents total deposited energy per average mass.
• Demonstrated consistency in energy calculations for a lung cancer retreatment case.
• Energy derived from MW total dose matched the sum of energy from multiple treatments.

Conclusions:

• The MW dose summation method provides an accurate measure of total energy deposited in organs.
• This method offers a reliable approach for dose accumulation verification in adaptive radiotherapy.