title: Acoustic power measurement of high-intensity focused ultrasound transducer using a pressure sensor.
abstract: The acoustic power of high-intensity focused ultrasound (HIFU) is an important parameter that should be measured prior to each treatment to guarantee effective and safe outcomes. A new calibration technique was developed that involves estimating the pressure distribution, calculating the acoustic power using an underwater pressure blast sensor, and compensating the contribution of harmonics to the acoustic power. The output of a clinical extracorporeal HIFU system (center frequency of ~1 MHz, p+ = 2.5-57.2 MPa, p(-) = -1.8 to -13.9 MPa, I(SPPA) = 513-22,940 W/cm(2), -6 dB size of 1.6 × 10 mm: lateral × axial) was measured using this approach and then compared with that obtained using a radiation force balance. Similarities were found between each method at acoustic power ranging from 18.2 W to 912 W with an electrical-to-acoustic conversion efficiency of ~42%. The proposed method has advantages of low weight, smaller size, high sensitivity, quick response, high signal-to-noise ratio (especially at low power output), robust performance, and easy operation of HIFU exposimetry measurement.
authors: Division of Engineering Mechanics, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore . Electronic address: yfzhou@ntu.edu.sg.
authors: Yufeng
authors: Y
authors: Zhou
mesh_terms: D000162:Acoustics; D002138:Calibration; D057086:High-Intensity Focused Ultrasound Ablation / Q000295:instrumentation*; D007101:Immersion; D011312:Pressure; D014159:Transducers
keywords: Acoustic power; High-intensity focused ultrasound (HIFU); Nonlinear effect; Radiation force balance