A 1372-element Large Scale Hemispherical Ultrasound Phased Array Transducer for Noninvasive Transcranial Therapy
- Sunnybrook Health Science Centre, 2075 Bayview Ave, Toronto, ON, M4N 3M5 (Canada)
Noninvasive transcranial therapy using high intensity focused ultrasound transducers has attracted high interest as a promising new modality for the treatments of brain related diseases. We describe the development of a 1372 element large scale hemispherical ultrasound phased array transducer operating at a resonant frequency of 306 kHz. The hemispherical array has a diameter of 31 cm and a 15.5 cm radius of curvature. It is constructed with piezoelectric (PZT-4) tube elements of a 10 mm in diameter, 6 mm in length and 1.4 mm wall thickness. Each element is quasi-air backed by attaching a cork-rubber membrane on the back of the element. The acoustic efficiency of the element is determined to be approximately 50%. The large number of the elements delivers high power ultrasound and offers better beam steering and focusing capability. Comparisons of sound pressure-squared field measurements with theoretical calculations in water show that the array provides good beam steering and tight focusing capability over an efficient volume of approximately 100x100x80 mm{sup 3} with nominal focal spot size of approximately 2.3 mm in diameter at -6 dB. We also present its beam steering and focusing capability through an ex vivo human skull by measuring pressure-squared amplitude after phase corrections. These measurements show the same efficient volume range and focal spot sizes at -6 dB as the ones in water without the skull present. These results indicate that the array is sufficient for use in noninvasive transcranial ultrasound therapy.
- OSTI ID:
- 21293562
- Journal Information:
- AIP Conference Proceedings, Vol. 1113, Issue 1; Conference: 8. international symposium on therapeutic ultrasound, Minneapolis, MN (United States), 10-13 Sep 2008; Other Information: DOI: 10.1063/1.3131452; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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