Dynamic intensity modulation segmentation method of orthogonal double-layer grating based on quadrant

Abstract

The invention discloses a dynamic intensity modulation segmentation method of an orthogonal double-layer grating based on a quadrant, specifically comprising the following steps of: S1: calculating the ray flux distribution under each radiation field through a radiotherapy planning system; S2: carrying out flux segmentation by adopting an orthogonal double-layer grating; S3: dividing quadrants, namely dividing a field area defined by four groups of upper, lower, left and right blades into at least two quadrants to obtain flux distribution and a corresponding blade sequence of each quadrant; S4: performing area planning on the flux curved surfaces of all quadrants to obtain a plurality of different areas, and determining the segmentation modes of the different areas; and S5: for any quadrant, adopting two mutually orthogonal sets of blades for the segmentation. According to the invention, the dynamic segmentation of the shape target area with any shape and multiple target areas are completed through the coordinated movement of the upper and lower orthogonal blades, the dynamic segmentation of the upper and lower layers of orthogonal double-layer gratings from two directions is realized, the end surface perspective between the blade pairs is avoided, and the segmentation efficiency is improved.

Description

technical field [0001] The invention relates to a dynamic intensity modulation segmentation method of a multi-leaf collimator, in particular to a dynamic intensity modulation segmentation method of an orthogonal double-layer grating based on sub-quadrants. Background technique [0002] When performing radiotherapy on tumors (target areas), in order to protect healthy tissues from damage, multi-leaf collimators (multi-leaf collimators, MLCs) are generally used to adjust the beam irradiation range and intensity to achieve beam flow Intensity modulated radiotherapy (IMRT). [0003] MLC was originally used in classical conformal radiation therapy to replace the stopper in conventional radiation therapy to form the desired shape of the radiation field. The MLC consists of two sets of closely spaced leaves. Each blade is made of tungsten alloy and is long and driven by a small electric motor. Compared with the field block, MLC conformal has significant advantages: it shortens t...

AI Technical Summary

Problems solved by technology

[0007] First, the projected width of the leaves of a single-layer MLC on the isocentral plane is usually between 0.5 cm and 1.0 cm, and the irradiation field formed by a single-layer MLC has a step-like boundary, which cannot be completely consistent with the expected smooth boundary of the target area

Although the conformity of the field of view can be improved by making the blade width of the MLC thinner and thinner, but because of the mechanical processing of the blade width, it cannot be theoretically infinitely thin, so the jagged field edge cannot be completely eliminate

[0008] Second, due to the fact that there are many pairs of closed blades within the range of the intensity-modulated field, but due to the consideration of mechanical and motion collision prevention, there is a gap between the paired closed blades, and there are about 20%-30% of the blade end faces. transmission;

[0009] Third, single-layer MLC cannot move in two directions to complete the dynamic target tracking treatment of the lungs

Images