Extrapolating tumor invasion margins for physiologically determined radiotherapy regions

In radiotherapy, the constant margin taken around the visible tumor is a very coarse approximation of the invasion margin of cancerous cells. In this article, a new formulation to estimate the invasion margin of a tumor by extrapolating low tumor densities in magnetic resonance images (MRIs) is proposed. The current imaging techniques are able to show parts of the tumor where cancerous cells are dense enough. However, tissue parts containing small number of tumor cells are not enhanced in images. We propose a way to estimate these parts using the tumor mass visible in the image. Our formulation is based on the Fisher-Kolmogorov Equation that is been widely used to model the growth of brain tumors. As a proof of concept, we show some promising preliminary results, which demonstrate the feasibility of the approach.