Optimisation-based thermal treatment planning for catheter-based ultrasound hyperthermia
Optimisation-based thermal treatment planning for catheter-based ultrasound hyperthermia
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DOI：
10.3109/02656730903341332
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发表时间：
2010-02-01
影响因子：
3.1
通讯作者：
Hsu, I-Chow
中科院分区：
文献类型：
--
作者：
Chen, Xin;Diederich, Chris J.;Hsu, I-Chow
针对基于导管的超声技术，开发了基于患者特定优化的热疗计划，用于预先评估所建议的敷贴器植入策略和确定初始施加功率设置。用于在高剂量率(HDR)近距离放射治疗植入物中提供3D可控热疗的间隔式和腔式加热器，由长度和角度可变功率控制的线性和扇形超声换能器阵列组成。根据HDR治疗计划，建立了包含相关解剖结构和植入物几何形状的三维生物热模型，以模拟这些超声敷贴器在导管植入物中诱导的温度分布。设计了一种基于温度的约束优化算法，并将其集成在有限元热求解器中，以确定最优的应用功率水平。温度表达的目标函数和约束被用来限制最高温度(T-max)，最大化目标覆盖(T-TARGET)，并最小化对正常组织和周围器官的热暴露。将基于优化的治疗计划应用于临床HDR植入物用于宫颈腔内治疗(n=3)和前列腺间质治疗(n=3)的典型实例。改变敷贴器的位置和方向、T-max和T-靶点，并计算每个计划的温度体积和热剂量体积直方图。优化方法提供了最佳的应用功率水平(4-24个独立的传感器部分)，从而使所有病例的温度分布一致或量身定做，目标体积中的温度指数T-90得到改善，周围非目标组织(如膀胱和直肠)的温度和热剂量(t(43，max)和lt；1min)可忽略不计。优化后的功率估计值的精度显示在
A patient-specific optimisation-based hyperthermia treatment planning program for catheter-based ultrasound technology was developed for a priori evaluation of proposed applicator implant strategies and determination of initial applied power settings. The interstitial and endocavity heating applicators, designed for delivering 3-D controllable hyperthermia within High Dose Rate (HDR) brachytherapy implants, consist of linear and sectored arrays of ultrasound transducers with variable power control in both length and angle. A 3D biothermal model, which incorporates relevant anatomical structures and implant geometries based upon HDR treatment planning, has been developed to simulate the temperature distributions induced by these ultrasound applicators within the catheter implants. A temperature-based constrained optimisation algorithm was devised and integrated within the finite-element thermal solver to determine the optimal applied power levels. A temperature-expressed objective function and constraints were employed to limit maximum temperature (T-max), maximise target coverage (T-target), and minimise thermal exposure to normal tissue and surrounding organs. The optimisation-based treatment planning was applied on representative examples of clinical HDR implants for endocavity treatment of cervix (n = 3) and interstitial treatment of prostate (n = 3). Applicator positioning and orientation, T-max and T-target were varied, and temperature volume and thermal dose volume histograms calculated for each plan. The optimisation approach provided optimal applied power levels (4-24 independent transducer sections) leading to conforming or tailored temperature distributions for all cases, as indicated with improved temperature index T-90 in the target volume and negligible temperature and thermal dose (t(43,max) < 1 min) exposure in surrounding non-targeted tissues, such as bladder and rectum. The precision of the optimised power estimates was shown to be within