Acoustic characterization of a neonate skull using a clinical MR-guided high intensity focused ultrasound system for pediatric neurological disorder treatment planning
© Colas et al; licensee BioMed Central Ltd. 2015
Published: 30 June 2015
Transcranial MR-guided Focused Ultrasound (TcMRgFUS) treatments are now clinically performed on adult patients for brain tumor or essential tremor therapies. However, no application has been proposed for children despite their thinner skull being less of an acoustic barrier and the presence of a fontanelle on neonates, which could constitute a natural acoustic window for the transmission of ultrasound waves. As there is minimal literature data on the attenuation and speed-of-sound of the skull in neonatal patients, the aim of this study was to perform the acoustic characterization of a neonate skull.
A 0.2 mm needle acoustic hydrophone was placed in a tank of degassed water and aligned to the geometric focus of a clinical HIFU transducer (Philips Sonalleve). The signals of the 256 elements of the phased array transducer were acquired as a baseline measurement using this hydrophone. A degased cadaveric neonate skull was then placed inside the tank between the hydrophone and the transducer. Acquisitions were performed for different angular orientations of the skull according to the sagittal and coronal axes in the range of ± 15°. Insertion losses (IL) and time-of-flight (TOF) delays due to the skull and the fontanelle were deducted from these measurements performed at 1 MHz and 1.2 MHz.
Results and conclusions
We acknowledge funding provided by the Brain Canada Multi-investigator Research Initiative, and the Focused Ultrasound Foundation. In-kind technical support provided by Philips Healthcare.
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