| Summary: | Abstract
This article involves two main objectives for BNCT system. First goal includes
optimization of cyclotron based BNCT collimator. Second goal is to calculate the neutron
flux and dosimetry system of Boron Neutron Capture Therapy (BNCT) in head and neck
soft tissue sarcoma (STS). A series of simulations has been carried out using a Monte Carlo
N Particle X program to find out the final composition and configuration of a collimator to
moderate the fast neutron flux which is generated from the thick beryllium target. The final
configuration for collimator design included 39 cm aluminium as moderator, 8.2 cm lithium
fluoride as fast neutron filter and 0.5 cm boron carbide as thermal neutron filter. Bismuth,
lead fluoride, and lead were chosen as the aperture, reflector, and gamma shielding,
respectively. Epithermal neutron fluxes in the suggested design were 2.83E9 n/cm2 s, while
other IAEA parameters for BNCT collimator design had been satisfied. In the next step, it
was simulated its dosimetry for head and neck soft tissue sarcoma. Simulations carried out
by varying the concentration of boron compounds in ORNL neck phantom model to
obtained the optimal dosimetry results. MCNPX calculation showed that the optimal depth
for thermal neutron was 4.8 cm in tissue phantom with the maximum dose rate was in GTV
on each boron concentration variation respectively. The irradiated time needed for this
therapy for each variables respectively less than an hour.
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