Special inhomogeneity effects for neutron irradiation of the lung and head

For a 14MeV neutron therapy facility the effects of inhomogeneities occuring in real irradiation of the lung and head had been studied in detail with the computer. The main calculation methods applied were the S(N)-approximation and the Monte Carlo method. Neutron fields with beams of circular and rectangular cross sections had been taken into account. The influence of different material layers with different atomic composition and densities on the neutron field had been studied and compared with the results of the homogeneous phantom and Co-60 dose curves. The comparison was done with the absorbed dose showing the relative differences in the mainly perturbed regions within and outside the inhomogeneity. For comparison the same problem had been treated for irradiations with Betatron-electrons. The combined application of beams of thermal reactor neutrons and boron pharmaca for tumor treatment in the head had been studied and compared with the application of fast neutrons