Forward and adjoint methods for radiotherapy planning

Area of Science:

• Nuclear Engineering
• Medical Physics
• Radiotherapy

Background:

• Radiotherapy planning requires accurate dose distribution calculations.
• Current methods may involve computationally intensive trial-and-error processes.
• Sensitivity theory offers a potential framework for optimization.

Purpose of the Study:

• To apply nuclear engineering-based sensitivity theory to radiotherapy planning.
• To calculate the sensitivity of dose distributions to radiation source parameters.
• To explore a novel, efficient method for radiotherapy optimization.

Main Methods:

• Mathematical equivalence of Boltzmann equation in forward and adjoint spaces was emphasized.
• Both forward and adjoint approaches were implemented for sensitivity calculations.
• Sensitivities of dose distributions in a mathematical phantom were computed.

Main Results:

• The study demonstrated the calculation of dose sensitivities to source position, angular distribution, intensity, and spectra.
• Tagging functionals with source origin (forward/adjoint) enabled efficient sensitivity analysis.
• The method leverages existing computational codes and hardware.

Conclusions:

• Sensitivity theory provides a powerful tool for radiotherapy planning.
• This approach offers a potentially faster and more accurate alternative to traditional methods.
• The findings suggest a new paradigm for radiation therapy optimization.