![]() | Only 14 pages are availabe for public view |
Abstract Radiation transport programs have been specialized to determine the radiation field of neutron therapy facilities. Neutron and gamma depth dose distributions, neutron spectra as well as secondary gammaradiation and recoil spectra can be calculated for homogeneous and in homogenous phantoms. The transport calculations are useful to optimize collimator systems and dose distributions inside the patient. Two fast neutron therapy facilities have been studied for their use in boron neutron capture therapy (BNCT). The first is the cyclotron facility at the University hospital at Essen and the second the themal - to-fast neutron converter at Munich research reactor FRM. Neutron and gamim flux spectra as well as dose distributions inside a patient phantom were calculated. The thermal neutron flux distribution was determined for different phantoms and field sizes. The thermal neutron flux depends strongly on field size and boron concentration. For the Converter beam with 8cm x 8cm field size we achieve a B-10 kerma contribution of 6% of the total skin kerma. Hereby 100 pg B-10 per I gm tissue are delivered in a tumor region localised between 1 cm and 5 cm depth. This value holds without any beam filter. |