Mixed integer programming approaches to exact minimization of total treatment time in cancer radiotherapy using multileaf collimators

Abstract

The effectiveness of radiation therapy for cancer depends on the patient remaining still during treatment. It is thus important to minimize the total treatment time (TTT). When such treatment is delivered using multileaf collimators in "step-and-shoot" mode, it consists of a sequence of collimator configurations, or patterns; for each, the patient is exposed to radiation for a specified time, or beam-on time. The TTT can thus be divided into the total beam-on time and the time spent reconfiguring the collimators. The latter can reasonably be approximated by the number of patterns, multiplied by a constant overhead time per pattern. Previous approaches to this problem have all been heuristic;..