A dose calculation algorithm for boron neutron capture therapy using convolution/superposition method.

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Biology

Background:

• The convolution/superposition (C/S) method, originally for photon dose calculation, is adapted for Boron Neutron Capture Therapy (BNCT).
• Accurate dose calculation is crucial for effective BNCT treatment planning.
• The TEGMA (total energy generated per unit mass) concept was introduced to represent neutron dose components.

Purpose of the Study:

• To develop and validate a C/S-based treatment planning system for BNCT.
• To evaluate the accuracy and speed of the C/S method compared to Monte Carlo simulations for BNCT dose calculations.
• To assess the feasibility of using C/S for clinical BNCT dose planning.

Main Methods:

• Neutron fluence distributions were calculated using MCNP6.2.
• A library of energy-groupwise TEGMA and KERMA was generated for the C/S code.
• Dose distributions were benchmarked against the PHITS Monte Carlo code in cuboid and human head phantoms.
• A human head phantom was created from DICOM CT images.

Main Results:

• The C/S method showed differences of 2-6% in boron doses and 4-9% in nitrogen doses compared to Monte Carlo.
• Isodose curves (60%-110%) were nearly identical between C/S and Monte Carlo in the human head phantom.
• The C/S method was significantly faster (<1 min) than PHITS (15.5-380 min).
• Discrepancies in hydrogen dose profiles were attributed to cross-section data and transport algorithm differences.

Conclusions:

• The developed C/S algorithm offers a high-speed alternative for BNCT dose calculations.
• The C/S method demonstrates fair accuracy, suitable for clinical treatment planning.
• Further refinement may be needed to address discrepancies in specific dose components and backscattering effects.