Dose Calculation and Treatment Planning for the Brookhaven NCT Facility

Abstract

Consistency of the calculated to measured fluxes and doses in phantoms is important for confidence in treatment planning for Boron Neutron Capture Therapy (BNCT) at the Brookhaven Medical Research Reactor (BMRR)¹. Two phantoms have been used to measure the thermal and epithermal flux and gamma dose distributions for irradiations at the BMRR and these are compared to MCNP calculations. Since MCNP calculations in phantoms or models would be lengthy if the calculations started each time with fission neutrons from the reactor core, a neutron source plane, which was verified by spectrum and flux measurements at the irradiation port, was designed. Measured doses in phantoms are especially important to verify the simulated neutron source plane. Good agreement between the calculated and measured values has been achieved and this neutron source plane is now used to predict flux and dose information for oncologists to form treatment plans as well as designing collimator and room shielding. In addition, a program using MCNP calculated results as input has been developed to predict reliable flux and dose distributions in the central coronal section of a head model for irradiation by the BMRR beam. Dosimetric comparisons and treatment examples are presented.