Frequency-dependent ultrasound transmission through the human skull

The development of large-aperture multiple-source transducer arrays for ultrasound transmission through the human skull has demonstrated the possibility of controlled acoustic energy delivery into the brain parenchyma. The individual control of acoustic parameters from each ultrasound source allows...

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Bibliographic Details
Published in:The Journal of the Acoustical Society of America 2005-04, Vol.117 (4_Supplement), p.2412-2412
Main Authors: White, P. Jason, Clement, G. T., Hynynen, Kullervo
Format: Article
Language:English
Online Access:Get full text
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Summary:The development of large-aperture multiple-source transducer arrays for ultrasound transmission through the human skull has demonstrated the possibility of controlled acoustic energy delivery into the brain parenchyma. The individual control of acoustic parameters from each ultrasound source allows for the correction of distortions arising from transmission through the skull bone and also opens up the possibility for electronic steering of the acoustic focus within the brain. To determine the efficacy of frequency modulation with such a device, this study examines the frequency dependence of ultrasound transmission in the range of 0.6–1.4 MHz through a series of seven points on each of three ex vivo human calvaria. Using broadband pulses, it is shown that the reflected spectra from the skull reveal information regarding the transmission energies at specific frequencies. In fact, there exists an inverse correlation between the reflected pressure amplitude and the transmitted pressure amplitude such that, for the frequency range under examination, approximately three local minima in the reflection spectra with the corresponding three peaks in transmission are observed. A noninvasive determination of the most efficient transmission frequency for a localized spatial region on a skull can yield an improvement of up to 3.5-dB in ultrasound intensity transmission.
ISSN:0001-4966
1520-8524
DOI:10.1121/1.4786266