A finite volume approach to dosimetric calculations in diffusing alpha-emitters radiation therapy

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Biology

Background:

• Alpha DaRT utilizes diffusing alpha-emitters for targeted radiation therapy.
• The diffusion-leakage (DL) model is crucial for predicting emitter distribution and alpha dose.
• Accurate dose calculation is essential for effective Alpha DaRT treatment planning.

Purpose of the Study:

• To develop and apply a finite volume (FV) approach for simulating the DL model in Alpha DaRT.
• To assess the impact of DL model parameter variations on alpha dose distribution and isodose position.
• To evaluate the effect of common modeling approximations on dose calculations.

Main Methods:

• A finite volume (FV) approach was implemented for 1D, 2D, and 3D DL model simulations.
• Realistic parameter ranges for desorption, diffusion, and leakage were used.
• The impact of source geometry and dose calculation approximations was quantified.

Main Results:

• Diffusion length variations caused the largest shift (∼1.5mm) in the 10Gy isodose position.
• Leakage and desorption probabilities shifted the 10Gy isodose by ∼0.5mm and ∼0.1mm, respectively.
• Modeled approximations resulted in negligible displacement (⩽0.01mm) of the 10Gy isodose.

Conclusions:

• Diffusion length is the most sensitive parameter in the DL model for Alpha DaRT.
• The FV approach provides a robust method for simulating Alpha DaRT dose distributions.
• Standard modeling approximations do not significantly compromise the accuracy of isodose position calculations.