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Background: It is challenging to visually identify tiny and concealed foreign objects within the body due to their small size and subcutaneous location while they can cause infections. Methods: A non‐contact photoacoustic system based on Rosencwaig‐Gersho photoacoustic theory and dual modulator method is developed for detecting foreign objects in meat. Result: The experiments conducted validate the successful development of this measurement technique with 10 μm spatial resolution and its corresponding mathematical model, demonstrating an 11% Mean Absolute Percentage Error (MAPE) in comparison to the experimental results. Dual modulator successfully regulates laser energy at MPE limit. Conclusion: The utilization of non‐contact photoacoustic signal intensity measurements enables the identification of foreign objects within the body. Further, the application of mathematical modelling can validate the measurement outcomes. These findings serve as a foundation for creating an affordable and straightforward foreign body detector. [ABSTRACT FROM AUTHOR]

Linear assumption on the level of stiffness in a tissue shows a significant correlation with disease. Photoacoustic imaging techniques that are non-contact by design have been developed in this study to detect differences in phantom (soft tissue mimicking materials) stiffness. This study aims to detect differences in phantom stiffness based on the results of image reconstruction at the resonance frequency. Four phantom agars with differing concentrations were made to achieve different stiffnesses. The position of each phantom agar's highest photoacoustic signal amplitude is identified by a frequency modulation sweep. The characterization results show an increase in resonance frequency along with an increase in phantom stiffness. The image difference can be detected because the intensity of the photoacoustic image in samples that have a resonance frequency with laser modulation is comparatively higher than in other samples. [ABSTRACT FROM AUTHOR]

Photoacoustic imaging is a hybrid modality that combines high-contrast and spectroscopy-based optical imaging specificity with the high spatial resolution of ultrasonography. This review highlights the development and progress of photoacoustic imaging technology over the past decade. This imaging technology has evolved to be more user-friendly, cost-effective, and portable, demonstrating its potential for diverse clinical applications. A potential clinical application lies in the use of photoacoustic imaging as a guiding tool for photothermal therapy. This review was conducted by initially filtering through three databases, namely, Google Scholar, PubMed, and Scopus, resulting in 460 articles published between 2019 and May 2023. Of these, 54 articles were deemed suitable for review after identification. The selected articles were research papers focusing on the development of therapeutic agents that enhance contrast in photoacoustic imaging. All reviewed articles tested these agents both in vitro and in vivo . This review focuses on wavelength absorption and radiation sources for photothermal therapy. The developed agents predominantly used NIR-I wavelengths, whereas the NIR-II region has been less explored, indicating significant potential for future research. This review provides comprehensive insights into the advancement of compounds serving as therapeutic agents and contrast agents in photoacoustic imaging-guided photothermal therapy., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Linear assumption on the level of stiffness in a tissue shows a significant correlation with disease. Photoacoustic imaging techniques that are non-contact by design have been developed in this study to detect differences in phantom (soft tissue mimicking materials) stiffness. This study aims to detect differences in phantom stiffness based on the results of image reconstruction at the resonance frequency. Four phantom agars with differing concentrations were made to achieve different stiffnesses. The position of each phantom agar's highest photoacoustic signal amplitude is identified by a frequency modulation sweep. The characterization results show an increase in resonance frequency along with an increase in phantom stiffness. The image difference can be detected because the intensity of the photoacoustic image in samples that have a resonance frequency with laser modulation is comparatively higher than in other samples., Competing Interests: Authors have no conflict of interest to declare., (2024 THE BIOPHYSICAL SOCIETY OF JAPAN.)