Patent ID: 9507886
Filing Date: 2016-11-29
CPC Classification: A61N,G06F,G06N,G16H

Claim Text:
1. A radiation therapy optimization method for a multi-objective optimization problem comprising a planning-target-volume surrounded by organs-at-risk in a patient to be treated using radiation, the method comprising: representing computed tomography data of the patient as a three-dimensional grid of coordinates divided into voxels which contain the planning-target-volume and the organs-at-risk; using a multi-objective optimizer to search successive generations of trial solutions to generate a database of optimized solutions that form a Pareto non-dominated set of solutions, which sample an estimation of a Pareto front to the multi-objective optimization problem where all solutions on the Pareto front are regarded as equally optimal, each trial solution being specified by a set of parameters defining beam orientations and fluence patterns which together define the radiation; evaluating each generation of trial solutions by: continuing to generate successive generations of the trial solutions according to a defined convergence criterion until the optimized solutions are determined according to prescribed criteria to be approximate Pareto-optimal solutions to the multi-objective optimization problem; and displaying the Pareto non-dominated set of solutions to a user by means of an interactive graphical interface; wherein the set of parameters defining the radiation of each trial solution includes beam orientations and fluence patterns for each one of a number of beams of radiation; and wherein the number of beams of radiation is optimized by: first beams closer than a certain minimum angle being merged together to form a single beam at an intermediate angle defined by fluence parameters constructed by averaging together parameters of the first beams; a penalty function being defined to prefer solutions requiring a fewer number of beams; beams being sorted by gantry angle, thus rearranging an order of their defining parameters, and being re-inserted into a genetic algorithm population; a size of a space of the parameters being reduced by sorting beams by gantry angle; and beam averaging being applied recursively.