A technique for the fast calculation of three-dimensional photon dose distributions using the superposition model

Area of Science:

• Medical Physics
• Radiotherapy Physics
• Computational Dosimetry

Background:

• Accurate 3D photon dose calculations are crucial for radiotherapy planning.
• The convolution/superposition approach offers high accuracy but is computationally intensive.
• Reducing computation time is essential for efficient clinical workflow.

Purpose of the Study:

• To develop and evaluate a novel method for accelerating 3D photon dose calculations using convolution/superposition.
• To maintain or improve the accuracy of dose calculations while significantly reducing computational time.

Main Methods:

• A single polyenergetic superposition model was developed using TERMA and a total energy deposition kernel.
• A novel CF method was introduced, combining a fast conventional model (modified power-law) with superposition on a coarse matrix.
• Correction factors were derived and interpolated to modify the conventional algorithm's dose calculation on a fine matrix.

Main Results:

• The CF method reduced the time for 3D dose matrix generation by at least a factor of 100.
• Accuracy was maintained with no significant loss compared to conventional superposition methods.
• The method demonstrated effectiveness in scenarios with large dose gradients and clinically relevant geometries.

Conclusions:

• The CF method offers a substantial speed-up for 3D photon dose calculations in radiotherapy.
• This technique effectively balances computational efficiency and dosimetric accuracy.
• The CF method presents a viable solution for faster and accurate dose calculations in clinical practice.