多叶准直器的结构设计

多叶准直器是加速器上用于射野适形的主要装置，具有简单有效的特点。现已广泛应用于适形、调强等放射治疗技术。为了安全有效地使用多叶准直器，有必要了解不同类型的多叶准直器，了解各种多叶准直器的结构特点及剂量学特征。本文旨在综述MLC的基本结构设计，介绍多叶准直器在加速器上的安装位置选择及影响，综述叶片纵截面和端面的设计方案和单、双聚焦特点，总结各厂家生产的多叶准直器的叶片宽度选择和实现叶片位置控制的各种机制。另外，文中介绍了双层多叶准直器等几种新型设计方案。

The configuration designs for multileaf collimators

Multileaf collimator （MLC） is an effective and convenient device of linacs for shaping radiation fields. It has been widely used in conformal and intensity modulated radiotherapy. To realize the efficiency and security of utilization of MLC, it is necessary to know the basic information and dosimetric characteristics of MLCs. The purpose of this article is to summarize the basic configuration designs for MLCs, to introduce different categories of MLCs＇ placements and corresponding effects, to review the designs for end shapes and cross - sectional shapes of MLC leaves and the characters of focused and double- focused leaves, and to summarize the leaf width arrangements and leaf position control systems from different manufactures. Several new designs of MLCs are also introduced in this article, such as dual MLCs.