Factors Associated with Energy Efficiency of Focused Ultrasound Through the Skull: A Study of 3D-Printed Skull Phantoms and Its Comparison with Clinical Experiences

Abstract

While focused ultrasound (FUS) is non-invasive, the ultrasound energy is attenuated by the skull which results in differences in energy efficiency among patients. In this study, we investigated the effect of skull variables on the energy efficiency of FUS. The thickness and density of the skull and proportion of the trabecular bone were selected as factors that could affect ultrasound energy transmittance. Sixteen 3D-printed skull models were designed and fabricated to reflect the three factors. The energy of each phantom was measured using an ultrasonic sound field energy measurement system. The thickness and proportion of trabecular bone affected the attenuation of transmitted energy. There was no difference in the density of the trabecular bone. In clinical data, the trabecular bone ratio showed a significantly greater correlation with dose/delivered energy than that of thickness and the skull density ratio. Currently, for clinical non-thermal FUS, the data are not sufficient, but we believe that the results of this study will be helpful in selecting patients and appropriate parameters for FUS treatment.

Low intensity focused ultrasound: a new prospect for the treatment of Parkinson’s disease

“…In addition, the skull weakens ultrasound energy which leads to variations in energy efficiency among different patients. Through the use of 3D printing technology, the correlation between skull composition and ultrasound energy can be determined and compared to actual skull components for determining the optimal ultrasound parameters required for clinical research [ 160 ]. Furthermore, there is potential hidden danger associated with LIFU when opening the BBB.…”

Exploiting Focused Ultrasound to Aid Intranasal Drug Delivery for Brain Therapy

“…However, obicodilation is conducted using FUS low intensity energy, and there’s a difference between the attenuation produced when the US wave crosses through the skull if it is a high or a low energy wave. A more recent study based on clinical data available from the obicodilation procedures on human clinical trials has advanced the hypothesis that the trabecular bone ratio showed a significantly greater correlation with dose/delivered energy than that of thickness and the SDR ( Kong et al, 2021 ).…”