Transcranial focused ultrasound is a novel noninvasive therapeutic modality for glioblastoma and other disorders of the brain. However, because the phase aberrations caused by the skull need to be corrected with computed tomography (CT) images, the transcranial transducer is tightly fixed on the patient’s head to avoid any variation in the relative position, and the focus shifting relies mainly on the capacity for electronic beam steering. Due to the presence of grating lobes and the rapid degradation of the focus quality with increasing focus-shifting distance, transcranial focus-shifting sonication may damage healthy brain tissue unintentionally. To reduce the risks associated with transcranial focused ultrasound therapy, linear frequency-modulated (FM) excitation is proposed. The k-space corrected pseudospectral time domain (PSTD) and acoustic holography approach based on the Rayleigh integral are combined to calculate the distribution of the deposited acoustic power. The corresponding simulation was performed with axial/lateral focus shifting at different distances. The distributions of the deposited acoustic power show that linear FM excitation can effectively suppress undesired prefocal grating lobes without compromising focus quality.

中文翻译：

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调频激励抑制经颅聚焦超声系统的栅瓣

经颅聚焦超声是一种用于胶质母细胞瘤和其他脑部疾病的新型无创治疗方式。然而，由于颅骨引起的相位畸变需要通过计算机断层扫描（CT）图像进行校正，因此经颅换能器紧紧固定在患者头部以避免相对位置发生任何变化，焦点转移主要依赖于容量用于电子束控制。由于栅瓣的存在和焦点质量随着焦点转移距离的增加而迅速下降，经颅焦点转移超声可能会无意中损害健康的脑组织。为了降低与经颅聚焦超声治疗相关的风险，提出了线性调频 (FM) 激励。结合k空间校正伪谱时域(PSTD)和基于瑞利积分的声全息方法来计算沉积声功率的分布。相应的模拟是在不同距离的轴向/横向焦点偏移下进行的。沉积声功率的分布表明，线性调频激励可以有效地抑制不需要的预焦栅瓣，而不会影响聚焦质量。