METHOD AND STATISTICAL VALIDATION TECHNIQUE FOR DETECTING DIFFERENCES BETWEEN RADIATION THERAPY IMAGES WITH APPLICATION TO THE DETECTION AND CONTROL OF RADIATION THERAPY TREATMENT DELIVERY ERRORS

摘要

A method and statistical validation technique detects differences between radiation therapy verification images with application to the detection and control of radiation therapy treatment delivery errors. The process takes reference and measured images of radiation therapy treatment fields and identifies deviations between them, for purposes of detecting and correcting delivery errors that could degrade treatment effectiveness or cause injury. For each pixel or voxel, the percent dose difference between measured and reference images is computed, and scaled by a quantity that depends on the local dose gradient, the measured image noise, and the measured positional variability of field-defining elements. The measured image is classified as error-free if the percent of scaled pixel values below the threshold exceeds a cutoff. The invention further comprises a method of measuring the noise and positional variability of field-defining elements, either from a single image or a population of images, as input to the detection algorithm. The invention further comprises a method of quantifying detection performance, allowing detection thresholds and cutoffs to be optimized.