Experimental Verification of the Accuracy of A 2-D Dose Calculation Algorithm for A d(8)D2(8) Neutron Beam Incident on Curved Surfaces

Abstract

The computerised treatment planning algorithm used at the University of Chicago Neutron Therapy Facility is based on linear interpolation of experimental beam data. These were obtained by relative ionisation measurements with a TE chamber in TE solution contained in a large square phantom with the beam incident normally onto a flat surface. Under these conditions, the d(50%) for a beam 12 x 12 cm2 at 105 cm from the target is 10.2 g.cm-2. In the dose calculation algorithm, surface curvature is taken into account by using the ratio of TPRs for the density weighted path lengths for the oblique and central rays. The purpose of this work is to test this calculation approximation by comparing measurements and calculations in a cylindrical, water-filled phantom with variable curvature cross section. Results of measurements and calculations are presented for two beam geometries.

Monte Carlo evaluation of a photon pencil kernel algorithm applied to fast neutron therapy treatment planning

“…A number of dose calculation algorithms for neutron therapy accounting for these effects have been developed in the past (Burger and Breit 1981). Kuchnir et al (1988) used linear interpolation of experimental beam data. Another approach was developed by Moyers et al (1988), a sophisticated point-kernel convolution technique.…”