PDF(Pubmed)
Abstract：
Thermal Magnetic Resonance (ThermalMR) integrates Magnetic Resonance Imaging (MRI) diagnostics and targeted radio-frequency (RF) heating in a single theranostic device. The requirements for MRI (magnetic field) and targeted RF heating (electric field) govern the design of ThermalMR applicators. We hypothesize that helmet RF applicators (HPA) improve the efficacy of ThermalMR of brain tumors versus an annular phased RF array (APA). An HPA was designed using eight broadband self-grounded bow-tie (SGBT) antennae plus two SGBTs placed on top of the head. An APA of 10 equally spaced SGBTs was used as a reference. Electromagnetic field (EMF) simulations were performed for a test object (phantom) and a human head model. For a clinical scenario, the head model was modified with a tumor volume obtained from a patient with glioblastoma multiforme. To assess performance, we introduced multi-target evaluation (MTE) to ensure whole-brain slice accessibility. We implemented time multiplexed vector field shaping to optimize RF excitation. Our EMF and temperature simulations demonstrate that the HPA improves performance criteria critical to MRI and enhances targeted RF and temperature focusing versus the APA. Our findings are a foundation for the experimental implementation and application of a HPA en route to ThermalMR of brain tumors.
摘要：
热磁共振（ThermalMR）集成了磁共振成像（MRI）诊断和靶向射频（RF）加热在一个单一的热诊断设备。MRI（磁场）和目标RF加热（电场）的要求决定了ThermalMR施加器的设计。我们假设头盔RF施加器（HPA）与环形相控RF阵列（APA）相比，可以提高脑肿瘤的ThermalMR的疗效。HPA是使用八个宽带自接地领结（SGBT）天线以及两个放置在头顶的SGBT设计的。使用10个等间隔SGBT的APA作为参考。对测试对象（体模）和人体头部模型进行了电磁场（EMF）模拟。对于临床场景，头部模型用一名多形性胶质母细胞瘤患者的肿瘤体积进行了改良.为了评估性能，我们引入了多目标评估（MTE）来确保全脑切片的可及性。我们实现了时间复用矢量场整形以优化RF激励。我们的EMF和温度模拟表明，与APA相比，HPA提高了对MRI至关重要的性能标准，并增强了靶向RF和温度聚焦。我们的发现为HPA在脑肿瘤ThermalMR中的实验实施和应用奠定了基础。
