TD14-Treatment Planning System from 2D to 3D

2G05-Treatment Planning System from 2D to 3D

Cheng B. Saw, PhD

UPMC Cancer Centers, Pittsburgh, PA  15232

This presentation will examine the underlying principles behind 2-dimensional (2D) and 3-dimensional (3D) treatment planning systems.  In 2D treatment planning systems, the dose distributions are computed in the central plane, the plane that passes through the beam axes.  The dose algorithms assume a cylindrical geometry and do not account for irregularities off the central plane.  An axial CT scan through the plane is often used for treatment planning purposes.  With the advancement of computer technology, fast speed computers with large storage capacity become available, making 3D treatment planning systems possible.  In 3D treatment planning system, a series of CT scans through the target volume is required.  The dose algorithms take into account the scattered components from off axes tissues.  Virtual simulation is feasible with 3D treatment planning system.  Surface and isodose rendering present newer technique of visualization.  The patient data acquisition, beam data collection, dose algorithms, display functions, and documentation will be discussed.

TD14 - 治疗计划系统——从2D到3D

Cheng B. Saw, PhD

UPMC Cancer Centers, Pittsburgh, PA  15232

本讲讲述2维和3维治疗计划系统的基本原理。在2维治疗计划系统中，计算通过射野中心轴的中心平面的剂量分布，剂量计算算法假设人体为柱状，不考虑中心平面之外的轮廓不规则，中心平面的CT图像常用于治疗计划。随着计算机技术的发展，大存储量的快速计算机的使用，使3维治疗计划系统成为可能。在3维治疗计划系统中，需要对靶区部位进行多层CT扫描，剂量计算算法考虑到离轴部位的散射影响，可以进行虚拟模拟，可以显示等剂量线和剂量面。本讲阐述患者数据获取、射线数据采集、剂量计算算法、计划显示以及文件管理。