Optimization of the computational efficiency of a 3D, collapsed cone dose calculation algorithm for brachytherapy

Area of Science:

• Medical Physics
• Radiotherapy
• Computational Dosimetry

Background:

• Brachytherapy dose calculations require accurate modeling of patient anatomy and heterogeneities.
• The collapsed cone method is a validated approach for dose calculation in brachytherapy.
• Successive-scattering approach enhances accuracy by separating scatter orders.

Purpose of the Study:

• To optimize the collapsed cone method for brachytherapy dose calculations.
• To investigate the optimal distribution of directions in successive-scattering calculations.
• To assess the impact of multiple-source configurations on calculation efficiency and accuracy.

Main Methods:

• Investigated the division of directions between first-scatter and higher-order scatter calculations.
• Analyzed the effect of multiple-source configurations on discretization artifacts.
• Evaluated the use of isotropic average approximations for point kernels at different energies.

Main Results:

• The largest fraction of directions should be allocated to first-scatter dose calculations.
• Multiple-source configurations significantly reduce the number of directions needed for acceptable artifact levels.
• Isotropic average approximations yield small dose differences at low/intermediate energies.

Conclusions:

• Collapsed cone calculations can be efficiently implemented for brachytherapy, comparable to external beam applications.
• Optimized methods, including parallel hardware, enable rapid dose calculation with heterogeneity and finite dimension considerations.
• These advancements are highly relevant for practical brachytherapy treatment planning.