Laser Deflection Acoustic Field Quantification: A Non-Invasive Measurement Technique for Focused Ultrasound Field Characterization

Xu, Yang; Liu, Hongde; Ma, Yaoan; Bai, Xiaoxue; Hu, Qiangwei; Cai, Yunpiao; Zhang, Hui; Huang, Tao; Liu, Mengmeng; Li, Jing; Ding, Mingyue; Yuchi, Ming

doi:10.3390/bioengineering13010022

Open AccessArticle

Laser Deflection Acoustic Field Quantification: A Non-Invasive Measurement Technique for Focused Ultrasound Field Characterization

by

Yang Xu

^1,2,†

,

Hongde Liu

^3,†,

Yaoan Ma

³,

Xiaoxue Bai

²,

Qiangwei Hu

³,

Yunpiao Cai

³

,

Hui Zhang

¹,

Tao Huang

²,

Mengmeng Liu

²,

Jing Li

²,

Mingyue Ding

^1,*

and

Ming Yuchi

^1,*

¹

Department of Biomedical Engineering, School of Life Science and Technology, and Advanced Biomedical Imaging Facility, Huazhong University of Science and Technology, Wuhan 430074, China

²

Hubei Medical Devices Quality Supervision and Test Institute, Wuhan 430075, China

³

School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China

^*

Authors to whom correspondence should be addressed.

^†

These authors contributed equally to this work.

Bioengineering 2026, 13(1), 22; https://doi.org/10.3390/bioengineering13010022

Submission received: 10 December 2025 / Revised: 20 December 2025 / Accepted: 23 December 2025 / Published: 26 December 2025

(This article belongs to the Special Issue Fundamentals and Novel Applications of Fluid Mechanics, Biomechanics, and Acoustics in Biomedical Engineering, 2nd Edition)

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Abstract

Focused ultrasound (FU) technology is extensively employed in clinical applications such as tumor ablation, Parkinson’s disease treatment, and neuropathic pain management. The safety and efficacy of FU therapy critically depend on the accurate quantification of the acoustic field, particularly the high-pressure distribution in focal region. To address the limitations of existing acoustic measurement techniques—including invasiveness, inability to measure high sound pressure, and system complexity—this study proposes a non-invasive method termed Laser Deflection Acoustic Field Quantification (LDAQ), based on the laser deflection principle. An experimental system was constructed utilizing the acousto-optic deflection effect, which incorporates precision displacement control, rotational scanning, and synchronized triggering. Through tomographic scanning, laser deflection images of the acoustic field were acquired at multiple orientations. An inversion algorithm using Radon transforms was proposed to reconstruct the refractive index gradient distributions from the variations of light intensity and spot displacement. An adaptive weighted fusion strategy was then employed to map these optical signals to the sound pressure field. To validate the LDAQ technique, an acoustic field generated by an FU transducer operating at 0.84 MHz was measured. The reconstructed results were compared with both hydrophone measurements and numerical simulations. The findings demonstrated high consistency among all three results within the focal zone. Full-field analysis yielded a root mean square error (RMSE) of 0.1102 between LDAQ and simulation, and an RMSE of 0.1422 between LDAQ and hydrophone measurements. These results confirm that LDAQ enables non-invasive and high-precision quantification of megapascal-level focused acoustic fields, offering a reliable methodology for acoustic field characterization to support FU treatment optimization and device standardization.

Keywords: focused ultrasound; acoustic field reconstruction; laser deflection; non-invasive measurement

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MDPI and ACS Style

Xu, Y.; Liu, H.; Ma, Y.; Bai, X.; Hu, Q.; Cai, Y.; Zhang, H.; Huang, T.; Liu, M.; Li, J.; et al. Laser Deflection Acoustic Field Quantification: A Non-Invasive Measurement Technique for Focused Ultrasound Field Characterization. Bioengineering 2026, 13, 22. https://doi.org/10.3390/bioengineering13010022

AMA Style

Xu Y, Liu H, Ma Y, Bai X, Hu Q, Cai Y, Zhang H, Huang T, Liu M, Li J, et al. Laser Deflection Acoustic Field Quantification: A Non-Invasive Measurement Technique for Focused Ultrasound Field Characterization. Bioengineering. 2026; 13(1):22. https://doi.org/10.3390/bioengineering13010022

Chicago/Turabian Style

Xu, Yang, Hongde Liu, Yaoan Ma, Xiaoxue Bai, Qiangwei Hu, Yunpiao Cai, Hui Zhang, Tao Huang, Mengmeng Liu, Jing Li, and et al. 2026. "Laser Deflection Acoustic Field Quantification: A Non-Invasive Measurement Technique for Focused Ultrasound Field Characterization" Bioengineering 13, no. 1: 22. https://doi.org/10.3390/bioengineering13010022

APA Style

Xu, Y., Liu, H., Ma, Y., Bai, X., Hu, Q., Cai, Y., Zhang, H., Huang, T., Liu, M., Li, J., Ding, M., & Yuchi, M. (2026). Laser Deflection Acoustic Field Quantification: A Non-Invasive Measurement Technique for Focused Ultrasound Field Characterization. Bioengineering, 13(1), 22. https://doi.org/10.3390/bioengineering13010022

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Laser Deflection Acoustic Field Quantification: A Non-Invasive Measurement Technique for Focused Ultrasound Field Characterization

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