OBJECTIVE: We develop and disseminate a model-based navigation (MBN) tool for acoustic dose delivery in the presence of skull aberrations that is easy to use by non-specialists.
METHODS: We pre-compute acoustic beams for thousands of virtual transducer locations on the scalp of the subject under study. We use the hybrid angular spectrum solver mSOUND, which runs in ∼4 s per solve per CPU yielding pre-computation times under 1 h for scalp meshes with up to 4000 faces and a parallelization factor of 5. We combine this pre-computed set of beam solutions with optical tracking, thus allowing real-time display of the tFUS beam as the operator freely navigates the transducer around the subject\' scalp. We assess the impact of MBN versus line-of-sight targeting (LOST) positioning in simulations of 13 subjects.
RESULTS: Our navigation tool has a display refresh rate of ∼10 Hz. In our simulations, MBN increased the acoustic dose in the thalamus and amygdala by 8-67 % compared to LOST and avoided complete target misses that affected 10-20 % of LOST cases. MBN also yielded a lower variability of the deposited dose across subjects than LOST.
CONCLUSIONS: MBN may yield greater and more consistent (less variable) ultrasound dose deposition than transducer placement with line-of-sight targeting, and thus could become a helpful tool to improve the efficacy of tFUS neuromodulation.
目的:我们开发并推广了一种基于模型的导航(MBN)工具,用于在存在颅骨像差的情况下进行声剂量传递,该工具易于非专业人员使用。
方法:我们预先计算了研究对象头皮上数千个虚拟换能器位置的声束。我们使用混合角谱求解器mSOUND,对于具有多达4,000个面和5的并行化因子的头皮网格,每个CPU的每次求解运行时间为〜4秒,预计算时间不到一小时。我们将这个预先计算的光束解集与光学跟踪相结合,从而允许实时显示的tFUS光束,因为操作者自由地导航周围的对象\'头皮换能器。我们在13名受试者的模拟中评估了MBN与视线瞄准(LOST)定位的影响。
结果:我们的导航工具的显示刷新率为~10Hz。在我们的模拟中,与LOST相比,MBN使丘脑和杏仁核的声剂量增加了8-67%,并避免了影响LOST病例10-20%的完全目标遗漏。MBN在受试者中产生的沉积剂量的变异性低于LOST。
结论:MBN可能产生更大和更一致的超声剂量沉积比换能器放置视线靶向,因此可能成为提高tFUS神经调节功效的有用工具。