Das S K, Clegg S T, Samulski T V
Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA.
Int J Hyperthermia. 1999 Jul-Aug;15(4):291-308. doi: 10.1080/026567399285666.
The optimization of power deposition for electromagnetic (EM) thermal therapy is investigated. Several goal or objective functions are examined using a generalized mathematical formulation. These include maximization of: (1) target power absorption, (2) the ratio of target to non-target power absorption, (3) target power absorption weighted by the ratio of target to non-target power absorption, and (4) target power absorption subject to the constraint that the non-target high power volume ('hot spot' volume) is below a chosen level. The merit of these functions was retrospectively tested using an anatomic data base containing 38 cancer patients that were clinically heated with EM phased arrays. CT and/or MRI image data were used to define relevant anatomic geometries and tissue properties for finite element numerical models. Power optimization is achieved by variation of seven available control parameters (four amplitudes and three phases) for these clinical array devices. The results indicate that site dependent improvements in target power absorption can be achieved using these goal functions relative to a configuration that utilizes equal phase and amplitude for the sources. The relative merit among these various functions favours an optimization strategy that maximizes the target power absorption weighted by the ratio of target power to non-target power absorption.
本文研究了电磁（EM）热疗中功率沉积的优化问题。使用广义数学公式对几个目标函数进行了研究。这些目标函数包括最大化：（1）目标功率吸收；（2）目标与非目标功率吸收之比；（3）以目标与非目标功率吸收之比加权的目标功率吸收；（4）在非目标高功率体积（“热点”体积）低于选定水平的约束条件下的目标功率吸收。使用包含38例接受EM相控阵临床加热的癌症患者的解剖数据库，对这些函数的优点进行了回顾性测试。CT和/或MRI图像数据用于为有限元数值模型定义相关的解剖几何形状和组织特性。通过改变这些临床阵列设备的七个可用控制参数（四个幅度和三个相位）来实现功率优化。结果表明，相对于对源使用相等相位和幅度的配置，使用这些目标函数可以实现目标功率吸收的部位依赖性改善。这些不同函数之间的相对优点有利于一种优化策略，即最大化以目标功率与非目标功率之比加权的目标功率吸收。
