Gate 7.2学习笔记（三）

一、定义几何

几何的定义是设计仿真的关键步骤，因为它是通过描述成像设备和要扫描的对象的几何定义。然后通过几何的组件跟踪粒子。

1、The world

<1> The world is the only volume already defined in GATE when starting a macro.

<2> All volumes are defined as daughters or grand-daughters of the world.

<3> The world volume is a typical example of a GATE volume and has predefined properties.

<4> The world volume is a box centred at the origin. For any particle, tracking stops when it escapes from the world volume.

<5> The world volume can be of any size and has to be large enough to include all volumes involved in the simulation.

# World# Define the world dimensions##/gate/world/geometry/setXLength 100 cm/gate/world/geometry/setYLength 100 cm/gate/world/geometry/setZLength 100 cm

2、Creating a volume

The tree includes the following commands:setMaterial: To assign a material to the volumeattachCrystalSD: To attach a crystal-SensitiveDetector to the volumeattachPhantomSD: To attach a phantom-SensitiveDetector to the volumeenable: To enable the volumedisable: To disable the volumedescribe: To describe the volumeThe tree includes sub-trees that relate to different attributes of the volume Volume_Name. The available sub-trees are:daughters: To insert a new 'daughter' in the volumegeometry: To control the geometry of the volumevis: To control the display attributes of the volumerepeaters: To apply a new 'repeater' to the volumemoves: To 'move' the volumeplacement: To control the placement of the volume

SPECT中的例子

# CRYSTAL# Create the crystal volume##/gate/SPECThead/daughters/name crystal/gate/SPECThead/daughters/insert box/gate/crystal/geometry/setXLength 1. cm/gate/crystal/geometry/setYLength  19. cm/gate/crystal/geometry/setZLength  28. cm/gate/crystal/placement/setTranslation  0. 0. 0. cm/gate/crystal/setMaterial NaI/gate/crystal/vis/setColor yellow

3、Repeating a volume

<1> 要创建X个相同的卷，不需要创建X个不同的卷。必须创建一个卷，然后重复。

<2> Repeating a volume有四种不同的方式：线性中继器，环形中继器，立方阵列中继器和象限中继器。

<3>要列出为卷Name_Volume定义的中继器，请使用：

/gate/Name_Volume/repeaters/info  

具体内容可参见下列网址

Users Guide V7.2:Defining a geometry - Wiki OpenGATE
http://wiki.opengatecollaboration.org/index.php/Users_Guide_V7.2:Defining_a_geometry#Repeating_a_volume

4、Placing a volume

使用子树定义几何体中卷的位置

/placement/