BNCT dose calculation in irregular fields using the sector integration method

Area of Science:

• Medical Physics
• Radiation Oncology
• Nuclear Engineering

Background:

• Irregular fields are crucial for Boron Neutron Capture Therapy (BNCT) to spare healthy tissues in superficial tumor treatments.
• Accurate dosimetry for irregular fields requires reliable calculation systems or custom measurements.
• The RA-6 reactor facility in Argentina is utilized for BNCT research.

Purpose of the Study:

• To implement and validate the sector-integration method for calculating dosimetric responses of irregular fields in BNCT.
• To establish a tool for redundant calculations in BNCT treatment planning.
• To assess the accuracy of the sector-integration method by comparing calculated and measured data.

Main Methods:

• The sector-integration method was applied to calculate dosimetric responses (neutron and photon dose, thermal neutron flux) for irregular fields.
• Input data consisted of dosimetric responses for circular fields measured at various depths in a water phantom using ionization and activation techniques.
• Circular fields were generated using shielding plates made of borated polyethylene and lead.

Main Results:

• The sector-integration method was successfully implemented for irregular field calculations on the central beam axis in a homogeneous medium.
• Calculated dosimetric responses for a 7x4 cm(2) rectangular field showed less than 3% difference in equivalent dose compared to measurements at any depth.
• The method demonstrated suitability for redundant calculations in BNCT.

Conclusions:

• The sector-integration method provides an accurate and reliable approach for calculating dosimetric responses of irregular fields in BNCT.
• This validated method can serve as a valuable tool for enhancing the safety and efficacy of BNCT for superficial tumors.
• The findings support the use of this method for secondary verification in clinical BNCT applications.