Image-Guided Radiation Therapy

摘要

The disclosed systems and methods for Image-Guided Radiation Therapy (IGRT), utilises an iterative approach which adjusts a treatment plan based on inter- or intra-fraction images to improve the accuracy of the radiation delivered during the overall treatment. The prescribed dose of radiotherapeutic radiation is mapped onto the patient's anatomy using an image acquired of the region, which is to be the target for radiotherapeutic radiation. Following beam-angle-optimisation, fluence optimisation and segmentation, the efficiency of delivery of each segment is determined using an objective function, and the segments ranked according to their efficiency. The plan proceeds with the choice of the most efficient segment (or segments) to be delivered first. When this radiation has been delivered, having been tracked to establish its distribution, this delivered distribution can be subtracted from the original prescribed dose and the process repeated so that the delivered radiation gradually converges on the original prescribed dose.

主权项

1. A radiotherapeutic apparatus for delivering a prescribed dose of radiotherapeutic radiation to a target region of patient tissue comprising a source for producing a directable beam of therapeutic radiation, wherein an image depicting patient anatomical data of at least the target region has been acquired and the prescribed dose has been mapped onto the image as the desired dose distribution to be achieved in the target region, the apparatus being adapted and configured to:
a) determine at least one beam angle corresponding to a direction from which the radiotherapeutic radiation is to be delivered from the source to the target region, and for each beam angle create a mask defining a beam outline which substantially matches an outline of the target region as seen from each beam angle; b) discretize the or each beam within its beam outline into a plurality of pencil beams; c) for each beam angle carry out a fluence optimisation process using pencil beam data from step b) and patient anatomical and target region data from the image to generate a distribution profile for a sub-dose to be delivered at that beam angle, the separate sub-doses from all the angles in combination substantially equalling the prescribed dose; d) segment each sub-dose distribution profile into segments, each segment comprising a plurality of pencil beams of matching fluence; e) determine the efficiency of all of the segments; f) deliver radiation in accordance with at least one of the most efficient segments of therapeutic radiation; g) track the radiation delivered in step f) to calculate the amount and distribution of radiation delivered during the or each segment relative to patient anatomical data from the image, and subtract this from the mapped prescribed dose to create a new prescribed dose, and adjust the sub-doses and/or part sub-doses remaining to be delivered accordingly, and h) repeat the steps above from step c) to step g).