title: Quantitative assessment of acoustic intensity in the focused ultrasound field using hydrophone and infrared imaging.
abstract: With the popularity of ultrasound therapy in clinics, characterization of the acoustic field is important not only to the tolerability and efficiency of ablation, but also for treatment planning. A quantitative method was introduced to assess the intensity distribution of a focused ultrasound beam using a hydrophone and an infrared camera with no prior knowledge of the acoustic and thermal parameters of the absorber or the configuration of the array elements. This method was evaluated in both theoretical simulations and experimental measurements. A three-layer model was developed to calculate the acoustic field in the absorber, the absorbed acoustic energy during the sonication and the consequent temperature elevation. Experiments were carried out to measure the acoustic pressure with the hydrophone and the temperature elevation with the infrared camera. The percentage differences between the derived results and the simulation are <4.1% for on-axis intensity and <21.1% for -6-dB beam width at heating times up to 360 ms in the focal region of three phased-array ultrasound transducers using two different absorbers. The proposed method is an easy, quick and reliable approach to calibrating focused ultrasound transducers with satisfactory accuracy.
authors: Biomedical Instrument Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China; School of Computer, Jiangxi University of Traditional Chinese Medicine, Nanchang, China.
authors: Ying
authors: Y
authors: Yu
authors: Guofeng
authors: G
authors: Shen
authors: Yufeng
authors: Y
authors: Zhou
authors: Jingfeng
authors: J
authors: Bai
authors: Yazhu
authors: Y
authors: Chen
mesh_terms: D000465:Algorithms; D002138:Calibration; D004867:Equipment Design; D019544:Equipment Failure Analysis; D057086:High-Intensity Focused Ultrasound Ablation / Q000295:instrumentation* / Q000592:standards*; D007259:Infrared Rays; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013817:Thermography / Q000295:instrumentation* / Q000592:standards*
keywords: Acoustic intensity; Beam width; Focused ultrasound; Hydrophone; Infrared imaging; Temperature elevation