A 256-element ultrasonic phased array system for the treatment of large volumes of deep seated tissue

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 46; no. 5; pp. 1254 - 1268
• Main Authors: Daum, D.R., Hynynen, K.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-09-1999; Institute of Electrical and Electronics Engineers
• Subjects: Ablation; Acoustic arrays; Acoustic coupling; Acoustic testing; Acoustics; Acoustoelectric effects; Arrays; Biological and medical sciences; Coagulation; Construction; Exact sciences and technology; Fundamental areas of phenomenology (including applications); In vivo; Large-scale systems; Lesions; Medical sciences; Miscellaneous; Muscles; Patient treatment; Phased arrays; Physics; Physiological models; Piezoelectric materials; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Spherical shells; Thigh; Tissue; Transduction; acoustical devices for the generation and reproduction of sound; Ultrasonic imaging; Ultrasonic transducers; Ultrasound; Human; Coagulation; Acoustic coupling; Phased array; Thermotherapy; Experimental study; MHz range; Nuclear magnetic resonance imaging; Piezoelectric ceramics; Composite material; Spherical shell; Tissue; Radius of curvature; High power; Testing equipment; Acoustic antenna; Ultrasonic transducer; Ceramic fiber; Hydrophone
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/58.796130

A 256-element phased array has been designed, constructed, and tested for ablative treatment of large focal volumes of deep seated tissue. The array was constructed from a 1.1-MHz, 1-3 composite piezoelectric spherical shell with a 10-cm radius of curvature and a 12-cm diameter. The array was tested to determine its electroacoustic efficiency and inter-element coupling under high acoustic power conditions. A series of in vivo porcine experiments demonstrated the ability to produce deep seated tissue lesions in thigh muscle using the large scale phased array. The array was used to heat and coagulate tissue volumes >5 cm/sup 3/ in a single ultrasound exposure using multiple foci and temporally scanned power deposition patterns. The spatial and temporal experimental results for large, heated focal volumes correlated very well with the simulated temperature response model for homogeneous tissue. A 25-cm/sup 3/ tissue volume was coagulated in a 90-min period using overlapping large ultrasound exposures.