A heuristic to isolate interfering bodies in the BNCT treatment planning system

In many real life applications involving geometries, a problem may arise if any two objects are intersecting where they should not be. This paper presents a solution to this problem. The particular application discussed here is BNCT (Boron Neutron Capture Therapy) which is an idealized form of radiation therapy providing a mechanism to destroy cancer cells with minimal damage to adjacent normal cells. The radiation treatment planning software (BNCT Rtpe) uses NURBS to represent various anatomical surfaces. For the successful working of the Monte Carlo simulation of neutron transport, no two bodies should intersect in this representation. There always exists the possibility that two or more objects intersect. This paper presents a heuristic to isolate any two given interfering bodies (represented as closed B-spline surfaces). It finds a vector, based on the region of intersection, along which one of the surfaces can be moved to minimally isolate it from the other surface. It successfully isolates the two surfaces while preserving the original shapes and relative orientation of the two surfaces. Future work involved truncation of the surfaces midway between the regions of intersection