Dose-rate scaling factor estimation of THOR BNCT test beam

Area of Science:

• Medical Physics
• Radiation Oncology
• Nuclear Engineering

Background:

• Boron Neutron Capture Therapy (BNCT) requires precise dosimetry for effective treatment.
• The Tsing Hua Open-Pool Reactor (THOR) facility developed an epithermal neutron test beam for BNCT research.
• Characterizing neutron beams is crucial for accurate dose delivery in clinical applications.

Purpose of the Study:

• To report dosimetry comparisons for the THOR epithermal neutron test beam.
• To derive dose-rate scaling factors (DRSFs) for accurate treatment planning using the NCTPlan code.
• To establish a methodology for characterizing new BNCT neutron beams.

Main Methods:

• Experimental measurements of depth dose-rate distributions using activation foils and dual ion chambers.
• Spectral analysis of neutron and gamma radiation at the beam exit.
• Monte Carlo simulations using the NCTPlan code with measured spectra as source functions.
• Determination of DRSFs by normalizing calculated dose distributions to experimental measurements in phantoms.

Main Results:

• In-phantom calculated and experimental dosimetry comparisons were performed.
• Dose-rate scaling factors (DRSFs) were successfully derived for the THOR test beam.
• The methodology enables accurate dose calculations for BNCT treatment planning.

Conclusions:

• The THOR epithermal neutron test beam dosimetry was validated through experimental and computational comparisons.
• Derived DRSFs facilitate accurate treatment planning with the NCTPlan code.
• The established approach will be applied to a new THOR epithermal beam for upcoming clinical studies.