Pub Date : 2025-10-09DOI: 10.1016/j.pacs.2025.100775
Mengyang Lu , Jingxian Wang , Jiayuan Peng , Boyi Li , Xin Liu
The rapid advancement of multispectral optoacoustic tomography (MSOT) has developed for label-free biomedical imaging by providing anatomical and functional visualization through multi-wavelength laser excitation and ultrasound detection. This technique offers high spatial resolution and deep-tissue imaging capabilities for biological applications. However, the substantial hardware cost and computational demand for high-quality in vivo imaging hinder its extensive development. To overcome these limitations, we propose a multi-wavelength graph convolutional network for sparse MSOT. Our approach solves the ill-conditioned sparse reconstruction problem through a graph learning framework integrated with a multi-wavelength sparse sampling strategy, which can model and leverage the intrinsic correlations in artifact distributions across diverse sparse transducer configurations. Comprehensive in vivo mouse experiments demonstrate that the proposed method provides a flexible and practical solution for high-performance sparse MSOT imaging under sparse conditions (16 transducer elements with the reconstruction SSIM of 0.92 ± 0.01 and PSNR of 27.74 ± 1.27).
{"title":"Multi-wavelength graph convolutional network for high-performance sparse multispectral optoacoustic tomography","authors":"Mengyang Lu , Jingxian Wang , Jiayuan Peng , Boyi Li , Xin Liu","doi":"10.1016/j.pacs.2025.100775","DOIUrl":"10.1016/j.pacs.2025.100775","url":null,"abstract":"<div><div>The rapid advancement of multispectral optoacoustic tomography (MSOT) has developed for label-free biomedical imaging by providing anatomical and functional visualization through multi-wavelength laser excitation and ultrasound detection. This technique offers high spatial resolution and deep-tissue imaging capabilities for biological applications. However, the substantial hardware cost and computational demand for high-quality <em>in vivo</em> imaging hinder its extensive development. To overcome these limitations, we propose a multi-wavelength graph convolutional network for sparse MSOT. Our approach solves the ill-conditioned sparse reconstruction problem through a graph learning framework integrated with a multi-wavelength sparse sampling strategy, which can model and leverage the intrinsic correlations in artifact distributions across diverse sparse transducer configurations. Comprehensive <em>in vivo</em> mouse experiments demonstrate that the proposed method provides a flexible and practical solution for high-performance sparse MSOT imaging under sparse conditions (16 transducer elements with the reconstruction SSIM of 0.92 ± 0.01 and PSNR of 27.74 ± 1.27).</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"46 ","pages":"Article 100775"},"PeriodicalIF":6.8,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-08DOI: 10.1016/j.pacs.2025.100770
Markus Saurer , Guenther Paltauf , Oliver Spitzer , Tobias Reitmayr , Gordana Djuras , Birgit Kornberger , Ulrike Kleb , Robert Nuster
Hairpin technology is being used as a replacement for the traditional winding stator in electric motors. In hairpin stator manufacturing, copper rods are used to achieve a higher slot fill factor. These rods are joined together in pairs through laser welding, forming a closed circuit. However, this welding process is prone to air inclusions in the welds, which can negatively impact the efficiency and durability of the motor. The present study aims to estimate the total volume of these air inclusions using laser ultrasonic measurements. Laser ultrasound is a fast, non-contact, non-destructive method that can cope with the limited sample accessibility, making it ideal for inline testing of these weld seams. To evaluate the effectiveness of laser ultrasound, a stator was intentionally manipulated prior to laser welding to favor the formation of air inclusions. The porosity of the weld seams was determined through computed tomography images. It was demonstrated that due to the complex geometry of the hairpin welds, leading to a complex ultrasound wave field, standard methods to estimate the porosity from laser ultrasound B-scans are difficult to apply. As an alternative approach, an algorithm that is based on artificial intelligence was utilized for the purpose of estimating the air inclusion volume in the welds from laser ultrasonic measurements. The outcomes demonstrated a median correlation of 0.6 between this estimate and the pore volume obtained from the computed tomography data, despite the utilization of only 48 samples. Moreover, these results were evaluated against a model where the labels were randomly mixed, and highly informative regions regarding pore volume were identified in the B-scans, which have the potential to accelerate the process of acquiring data.
{"title":"Artificial intelligence-assisted laser ultrasound method for the estimation of porosity in hairpin weld seams","authors":"Markus Saurer , Guenther Paltauf , Oliver Spitzer , Tobias Reitmayr , Gordana Djuras , Birgit Kornberger , Ulrike Kleb , Robert Nuster","doi":"10.1016/j.pacs.2025.100770","DOIUrl":"10.1016/j.pacs.2025.100770","url":null,"abstract":"<div><div>Hairpin technology is being used as a replacement for the traditional winding stator in electric motors. In hairpin stator manufacturing, copper rods are used to achieve a higher slot fill factor. These rods are joined together in pairs through laser welding, forming a closed circuit. However, this welding process is prone to air inclusions in the welds, which can negatively impact the efficiency and durability of the motor. The present study aims to estimate the total volume of these air inclusions using laser ultrasonic measurements. Laser ultrasound is a fast, non-contact, non-destructive method that can cope with the limited sample accessibility, making it ideal for inline testing of these weld seams. To evaluate the effectiveness of laser ultrasound, a stator was intentionally manipulated prior to laser welding to favor the formation of air inclusions. The porosity of the weld seams was determined through computed tomography images. It was demonstrated that due to the complex geometry of the hairpin welds, leading to a complex ultrasound wave field, standard methods to estimate the porosity from laser ultrasound B-scans are difficult to apply. As an alternative approach, an algorithm that is based on artificial intelligence was utilized for the purpose of estimating the air inclusion volume in the welds from laser ultrasonic measurements. The outcomes demonstrated a median correlation of 0.6 between this estimate and the pore volume obtained from the computed tomography data, despite the utilization of only 48 samples. Moreover, these results were evaluated against a model where the labels were randomly mixed, and highly informative regions regarding pore volume were identified in the B-scans, which have the potential to accelerate the process of acquiring data.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"46 ","pages":"Article 100770"},"PeriodicalIF":6.8,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-04DOI: 10.1016/j.pacs.2025.100773
Qiangzhou Rong , Carlos Taboada , Van Tu Nguyen , Rui Yao , Jesse Delia , Yushun Zeng , Xiaoyi Zhu , Qifa Zhou , Junjie Yao
A primary focus of contemporary biology is to understand how internal molecules influence natural development. Many amphibians serve as highly effective model organisms for this research due to their rapid growth rates and transparent tissues, which facilitate high-resolution imaging. In our research, we utilized two complementary photoacoustic microscopy (PAM) configurations: hyperspectral PAM (HS-PAM) and ultrafast functional PAM (UFF-PAM). HS-PAM enabled us to achieve cellular-level resolution in vitro, while UFF-PAM allowed us to capture hemodynamic changes of adult specimens in vivo. We monitored the morphological changes in glassfrogs from neurulation to the tadpole stage by detecting a variety of intrinsic contrasts, including DNA/RNA, yolk proteins, lipids, hemoglobin, and melanin. The PAM images provided detailed depictions of anatomical development. To further explore the versatility of these systems, we also imaged tissue structures within the skeletal muscle, liver, and fat tissue of other treefrog species. Additionally, we monitored blood flow dynamics in two species of glassfrogs under both awake and under anesthesia. Overall, our findings demonstrate that PAM is a powerful and versatile method, that can be coupled with different species of amphibians to inform applications in developmental biology.
{"title":"Label-free photoacoustic imaging of glassfrog development","authors":"Qiangzhou Rong , Carlos Taboada , Van Tu Nguyen , Rui Yao , Jesse Delia , Yushun Zeng , Xiaoyi Zhu , Qifa Zhou , Junjie Yao","doi":"10.1016/j.pacs.2025.100773","DOIUrl":"10.1016/j.pacs.2025.100773","url":null,"abstract":"<div><div>A primary focus of contemporary biology is to understand how internal molecules influence natural development. Many amphibians serve as highly effective model organisms for this research due to their rapid growth rates and transparent tissues, which facilitate high-resolution imaging. In our research, we utilized two complementary photoacoustic microscopy (PAM) configurations: hyperspectral PAM (HS-PAM) and ultrafast functional PAM (UFF-PAM). HS-PAM enabled us to achieve cellular-level resolution <em>in vitro</em>, while UFF-PAM allowed us to capture hemodynamic changes of adult specimens <em>in vivo</em>. We monitored the morphological changes in glassfrogs from neurulation to the tadpole stage by detecting a variety of intrinsic contrasts, including DNA/RNA, yolk proteins, lipids, hemoglobin, and melanin. The PAM images provided detailed depictions of anatomical development. To further explore the versatility of these systems, we also imaged tissue structures within the skeletal muscle, liver, and fat tissue of other treefrog species. Additionally, we monitored blood flow dynamics in two species of glassfrogs under both awake and under anesthesia. Overall, our findings demonstrate that PAM is a powerful and versatile method, that can be coupled with different species of amphibians to inform applications in developmental biology.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"46 ","pages":"Article 100773"},"PeriodicalIF":6.8,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-28DOI: 10.1016/j.pacs.2025.100772
Wei Wei , Kelu Zhou , Ruyue Cui , Zhengguo Shang , Hongpeng Wu , Lei Dong
High-precision detection of acetylene (C₂H₂) concentration plays a vital role in industrial safety, environmental monitoring, and fault diagnosis of power equipment. This paper reports a highly sensitive light-induced thermoelastic spectroscopy (LITES) C₂H₂ sensor based on a piezoelectric micromachined ultrasound transducer (PMUT). The sensor employs an eight-cantilever PMUT structure at the micrometer scale as its sensing element, effectively converting minute thermal deformations into larger displacements to achieve enhanced mechanical amplification effects. The novel cantilever beam structure design increases the PMUT resonance frequency to a high frequency of 198.8 kHz while simultaneously enhancing the LITES signal by a factor of 45. A spot-concentrated miniature multi-pass cell designed for the novel PMUT structure further enhances detection sensitivity and stability by amplifying the optical path length by 70 times through optical folding. Experimental results demonstrate that the sensor exhibits excellent linear response (R² = 0.99936) and long-term stability for C₂H₂ concentration detection, achieving a minimum detection limit of 2 ppm (@64 s). Compared with existing C₂H₂ optical detection technologies, PMUT-based LITES C₂H₂ sensor not only demonstrates outstanding detection performance but also offers CMOS-compatible fabrication advantages, providing a novel approach for the development of highly sensitive, portable, easily integrated, and low-cost C₂H₂ detection systems.
{"title":"PMUT enhanced light-induced thermoelastic spectroscopy","authors":"Wei Wei , Kelu Zhou , Ruyue Cui , Zhengguo Shang , Hongpeng Wu , Lei Dong","doi":"10.1016/j.pacs.2025.100772","DOIUrl":"10.1016/j.pacs.2025.100772","url":null,"abstract":"<div><div>High-precision detection of acetylene (C₂H₂) concentration plays a vital role in industrial safety, environmental monitoring, and fault diagnosis of power equipment. This paper reports a highly sensitive light-induced thermoelastic spectroscopy (LITES) C₂H₂ sensor based on a piezoelectric micromachined ultrasound transducer (PMUT). The sensor employs an eight-cantilever PMUT structure at the micrometer scale as its sensing element, effectively converting minute thermal deformations into larger displacements to achieve enhanced mechanical amplification effects. The novel cantilever beam structure design increases the PMUT resonance frequency to a high frequency of 198.8 kHz while simultaneously enhancing the LITES signal by a factor of 45. A spot-concentrated miniature multi-pass cell designed for the novel PMUT structure further enhances detection sensitivity and stability by amplifying the optical path length by 70 times through optical folding. Experimental results demonstrate that the sensor exhibits excellent linear response (R² = 0.99936) and long-term stability for C₂H₂ concentration detection, achieving a minimum detection limit of 2 ppm (@64 s). Compared with existing C₂H₂ optical detection technologies, PMUT-based LITES C₂H₂ sensor not only demonstrates outstanding detection performance but also offers CMOS-compatible fabrication advantages, providing a novel approach for the development of highly sensitive, portable, easily integrated, and low-cost C₂H₂ detection systems.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"46 ","pages":"Article 100772"},"PeriodicalIF":6.8,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-27DOI: 10.1016/j.pacs.2025.100771
Linxin Yang , Han Wu , Jing Chen , Wei Wang , Zhenxiu Zhang , Jiaping Feng , Wanbing Qiu , Fajin Dong , Ning Lin , Fengyi Yuan
Sarcopenia, commonly observed in diabetes, is characterized by reduced muscle mass and function. However, the relationship between muscle oxygen saturation (SO₂) and sarcopenia remains unclear. Photoacoustic imaging (PAI) offers a promising method for assessment. This study aimed to evaluate SO₂ distribution in diabetic sarcopenic patients using PAI and explore associations with clinical parameters. Type 2 diabetes patients (≥ 10 years) underwent PAI of the gastrocnemius and vastus lateralis muscles. Sarcopenia was diagnosed by AWGS 2019/2020 criteria. SO₂ values stratified patients into hypoxia, intermediate, and hyperoxia groups. The study included 64 sarcopenic and 115 non-sarcopenic patients. Mean SO₂ was significantly lower in sarcopenia (63.28 % vs. 66.26 %, P < 0.001). PAI-measured SO₂ was an independent protective factor (β = −0.10, P = 0.001). In conclusion, PAI-assessed SO₂ is associated with sarcopenia and may serve as an early screening biomarker.
{"title":"Muscle oxygen saturation stratification by photoacoustic imaging in diabetic sarcopenia: Association with disease status","authors":"Linxin Yang , Han Wu , Jing Chen , Wei Wang , Zhenxiu Zhang , Jiaping Feng , Wanbing Qiu , Fajin Dong , Ning Lin , Fengyi Yuan","doi":"10.1016/j.pacs.2025.100771","DOIUrl":"10.1016/j.pacs.2025.100771","url":null,"abstract":"<div><div>Sarcopenia, commonly observed in diabetes, is characterized by reduced muscle mass and function. However, the relationship between muscle oxygen saturation (SO₂) and sarcopenia remains unclear. Photoacoustic imaging (PAI) offers a promising method for assessment. This study aimed to evaluate SO₂ distribution in diabetic sarcopenic patients using PAI and explore associations with clinical parameters. Type 2 diabetes patients (≥ 10 years) underwent PAI of the gastrocnemius and vastus lateralis muscles. Sarcopenia was diagnosed by AWGS 2019/2020 criteria. SO₂ values stratified patients into hypoxia, intermediate, and hyperoxia groups. The study included 64 sarcopenic and 115 non-sarcopenic patients. Mean SO₂ was significantly lower in sarcopenia (63.28 % vs. 66.26 %, P < 0.001). PAI-measured SO₂ was an independent protective factor (β = −0.10, P = 0.001). In conclusion, PAI-assessed SO₂ is associated with sarcopenia and may serve as an early screening biomarker.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"46 ","pages":"Article 100771"},"PeriodicalIF":6.8,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145220852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-10DOI: 10.1016/j.pacs.2025.100769
Jie Chen , Xianmei Qian , Wenyue Zhu , Qiang Liu , Jianjie Zheng , Tao Yang , Tengfei Yang
Accurate atmospheric aerosol absorption measurements are critical for advancing our understanding of global climate effects and reginal meteorological processes. In this paper, a multi-pass differential photoacoustic spectrometer (MP-DPAS) worked at 1064 nm, was developed for the in-situ measurement of atmospheric aerosol absorption coefficients (Abs). By employing the multi-pass configuration, 22 reflections of the incident laser were achieved, thereby the photoacoustic signal was enhanced by a factor of ten. Meanwhile, the differential configuration not only suppress background noise but also amplifies the signal by a factor of two. Consequently, the MP-DPAS achieved a minimum detection limit of 0.05 Mm−1 within an integration time of 110 s and a precision of 1.4 Mm−1. The accuracy of the MP-DPAS was validated by comparing the measured Abs with the calculated Abs of Mie scattering theory and the variation of particle size distribution measured by SMPS (Scanning Mobility Particle Sizer).
{"title":"A multi-pass differential photoacoustic spectrometer at 1064 nm for ambient aerosol absorption","authors":"Jie Chen , Xianmei Qian , Wenyue Zhu , Qiang Liu , Jianjie Zheng , Tao Yang , Tengfei Yang","doi":"10.1016/j.pacs.2025.100769","DOIUrl":"10.1016/j.pacs.2025.100769","url":null,"abstract":"<div><div>Accurate atmospheric aerosol absorption measurements are critical for advancing our understanding of global climate effects and reginal meteorological processes. In this paper, a multi-pass differential photoacoustic spectrometer (MP-DPAS) worked at 1064 nm, was developed for the in-situ measurement of atmospheric aerosol absorption coefficients (Abs). By employing the multi-pass configuration, 22 reflections of the incident laser were achieved, thereby the photoacoustic signal was enhanced by a factor of ten. Meanwhile, the differential configuration not only suppress background noise but also amplifies the signal by a factor of two. Consequently, the MP-DPAS achieved a minimum detection limit of 0.05 Mm<sup>−1</sup> within an integration time of 110 s and a precision of 1.4 Mm<sup>−1</sup>. The accuracy of the MP-DPAS was validated by comparing the measured Abs with the calculated Abs of Mie scattering theory and the variation of particle size distribution measured by SMPS (Scanning Mobility Particle Sizer).</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"46 ","pages":"Article 100769"},"PeriodicalIF":6.8,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-10DOI: 10.1016/j.pacs.2025.100766
Johanna Fuchte, Felix Wachter, Merle Claßen, Hannah Vogt-Wolz, Lars-Philip Paulus, Henriette Mandelbaum, Adrian Buehler, Gregor Siebenlist, Jörg Jüngert, Joachim Wölfle, André Hörning, Ferdinand Knieling, Adrian P. Regensburger , Alexander Schnell
Cystic fibrosis (CF) affects the gastrointestinal tract, but assessing gastrointestinal transit usually requires invasive procedures or exposure to ionizing radiation. Contrast-enhanced multispectral optoacoustic tomography (CE-MSOT) offers a novel, non-invasive, and radiation-free approach to assess gastrointestinal function by orally administered dyes. In this clinical pilot-study five patients with cystic fibrosis and four healthy volunteers received CE-MSOT before and 6-times hourly after a standardized breakfast with Indocyanin green (ICG) as dye. The gastric antrum, terminal ileum and sigmoid colon were recorded and MSOT signals spectrally unmixed to detect ICG signals to determine the transit time. ICG excretion was confirmed by fluorescence imaging of stool samples. MSOT ICG signals were detected earlier in the terminal ileum of CF patients, reaching a maximum after 120 min (p = 0.0079), compared to 240 min (p = 0.0286) in healthy controls after ICG intake (p = 0.0159). In CF patients, ICG signal was further detected in the sigmoid colon from 240 min onwards (p = 0.0079 after 300 min). But, no significant changes in the ICG signal were observed in the sigmoid colon of controls. Furthermore, signals of ICG were verified in 12 of 19 stool samples by fluorescence imaging. In this study, we demonstrated the potential of CE-MSOT for functional imaging of the intestine in CF patients and revealed faster intestinal transit in CF patients compared to healthy controls.
囊性纤维化（CF）影响胃肠道，但评估胃肠道运输通常需要侵入性手术或暴露于电离辐射。对比增强的多光谱光声断层扫描（CE-MSOT）提供了一种新的、无创的、无辐射的方法，通过口服染料来评估胃肠道功能。在这项临床试点研究中，5名囊性纤维化患者和4名健康志愿者在标准化早餐前和早餐后分别接受CE-MSOT治疗，每小时6次，早餐时使用吲哚青素绿（ICG）作为染料。记录胃窦、回肠末端和乙状结肠，对MSOT信号进行频谱分离，检测ICG信号，确定传递时间。粪便标本的荧光成像证实ICG排泄。CF患者回肠末端检测到MSOT ICG信号较早，在摄入ICG后120 min （p = 0.0079）达到最大值，而健康对照组为240 min (p = 0.0286)（p = 0.0159）。在CF患者中，从240 min开始在乙状结肠进一步检测到ICG信号（300 min后p = 0.0079）。对照组乙状结肠ICG信号未见明显变化。此外，19份粪便样本中有12份通过荧光成像证实了ICG信号。在这项研究中，我们证明了CE-MSOT对CF患者肠道功能成像的潜力，并揭示了CF患者的肠道运输速度比健康对照组更快。
{"title":"Contrast-enhanced multispectral optoacoustic tomography for the assessment of the gastrointestinal transit in patients with cystic fibrosis","authors":"Johanna Fuchte, Felix Wachter, Merle Claßen, Hannah Vogt-Wolz, Lars-Philip Paulus, Henriette Mandelbaum, Adrian Buehler, Gregor Siebenlist, Jörg Jüngert, Joachim Wölfle, André Hörning, Ferdinand Knieling, Adrian P. Regensburger , Alexander Schnell","doi":"10.1016/j.pacs.2025.100766","DOIUrl":"10.1016/j.pacs.2025.100766","url":null,"abstract":"<div><div>Cystic fibrosis (CF) affects the gastrointestinal tract, but assessing gastrointestinal transit usually requires invasive procedures or exposure to ionizing radiation. Contrast-enhanced multispectral optoacoustic tomography (CE-MSOT) offers a novel, non-invasive, and radiation-free approach to assess gastrointestinal function by orally administered dyes. In this clinical pilot-study five patients with cystic fibrosis and four healthy volunteers received CE-MSOT before and 6-times hourly after a standardized breakfast with Indocyanin green (ICG) as dye. The gastric antrum, terminal ileum and sigmoid colon were recorded and MSOT signals spectrally unmixed to detect ICG signals to determine the transit time. ICG excretion was confirmed by fluorescence imaging of stool samples. MSOT ICG signals were detected earlier in the terminal ileum of CF patients, reaching a maximum after 120 min (p = 0.0079), compared to 240 min (p = 0.0286) in healthy controls after ICG intake (p = 0.0159). In CF patients, ICG signal was further detected in the sigmoid colon from 240 min onwards (p = 0.0079 after 300 min). But, no significant changes in the ICG signal were observed in the sigmoid colon of controls. Furthermore, signals of ICG were verified in 12 of 19 stool samples by fluorescence imaging. In this study, we demonstrated the potential of CE-MSOT for functional imaging of the intestine in CF patients and revealed faster intestinal transit in CF patients compared to healthy controls.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"46 ","pages":"Article 100766"},"PeriodicalIF":6.8,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-08DOI: 10.1016/j.pacs.2025.100768
Chongyue Yan , Qiaoyun Wang , Tianyu Li , Zhiqi Gao , Yinji Chen , Ziheng Zhu , Zhigang Li , Dongxiao Hou , Qiang Liu
Photoacoustic spectroscopy (PAS) has been widely used for detecting trace gases, but enhancing sound pressure detection capability of the acoustic sensor is crucial for improving gas detection sensitivity of the PAS system. In this paper, a complementary interdigital (CID) cantilever Fabry-Perot (F-P) fiber optic acoustic sensor (FOAS) was developed. Experimental results demonstrated that the CID cantilever operated at its resonance frequency of 1010 Hz exhibited a high sensitivity of 923.7 nm/Pa, and exhibited a signal-to-noise ratio of 72.2 dB and a minimum detectable pressure of 16.4 μPa/Hz 1/2 at 1 kHz. In the concentration range of 20 ppm to 100 ppm, the sensitivity of PAS to C₂H₂ gas was 3.02 pm/ppm and the detection limits of C₂H₂ in N₂ background was 30.17 ppb. This design employs highly sensitive cantilevers with tunable resonance, enhancing the gas detection sensitivity of the PAS system by leveraging resonant frequency matching and signal amplification.
{"title":"Photoacoustic spectroscopy detection based on complementary interdigital cantilever enhanced Fabry-Perot acoustic sensor","authors":"Chongyue Yan , Qiaoyun Wang , Tianyu Li , Zhiqi Gao , Yinji Chen , Ziheng Zhu , Zhigang Li , Dongxiao Hou , Qiang Liu","doi":"10.1016/j.pacs.2025.100768","DOIUrl":"10.1016/j.pacs.2025.100768","url":null,"abstract":"<div><div>Photoacoustic spectroscopy (PAS) has been widely used for detecting trace gases, but enhancing sound pressure detection capability of the acoustic sensor is crucial for improving gas detection sensitivity of the PAS system. In this paper, a complementary interdigital (CID) cantilever Fabry-Perot (F-P) fiber optic acoustic sensor (FOAS) was developed. Experimental results demonstrated that the CID cantilever operated at its resonance frequency of 1010 Hz exhibited a high sensitivity of 923.7 nm/Pa, and exhibited a signal-to-noise ratio of 72.2 dB and a minimum detectable pressure of 16.4 μPa/Hz <sup>1/2</sup> at 1 kHz. In the concentration range of 20 ppm to 100 ppm, the sensitivity of PAS to C₂H₂ gas was 3.02 pm/ppm and the detection limits of C₂H₂ in N₂ background was 30.17 ppb. This design employs highly sensitive cantilevers with tunable resonance, enhancing the gas detection sensitivity of the PAS system by leveraging resonant frequency matching and signal amplification.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"46 ","pages":"Article 100768"},"PeriodicalIF":6.8,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-05DOI: 10.1016/j.pacs.2025.100767
Wenzhe Wang , Zhiyu Feng , Yachao Jiang , Jie Zhang , Shiyu Yan , Xiaohong Cao , Ping Lu , Chaotan Sima
A topological optimization method for photoacoustic resonators is proposed as the Method of Moving Asymptotes with Bernstein Polynomials (MMA-BP). This method is demonstrated in a ppt-level ultra-sensitive photoacoustic spectroscopy gas sensor using miniaturized vase-type photoacoustic cell (V-PAC). The V-PAC has a volume of merely 5 mL and achieves a minimum detection limit of 281 ppt for C2H2 with an integration time of 768 s, corresponding to a normalized noise equivalent absorption of 4.46 × 10⁻9∙cm⁻1∙Hz⁻1/2 with a single optical path. It represents an improvement of approximately 14 times beyond that of using the conventional T-type PAC. We experimentally investigated consequent frequency shifts within conventional PACs with thin resonator tubes, and determined the influence of losses on the resonant frequency shift. The geometric contraction effect in vase-type PAC is also investigated. The proposed topological MMA-BP method and implementations provide a universal approach to establish optimized PAC structures for photoacoustic gas detection.
{"title":"Topological optimization method “MMA-BP” for photoacoustic resonator and implementations in ppt-level gas sensor using miniaturized vase-type photoacoustic cells","authors":"Wenzhe Wang , Zhiyu Feng , Yachao Jiang , Jie Zhang , Shiyu Yan , Xiaohong Cao , Ping Lu , Chaotan Sima","doi":"10.1016/j.pacs.2025.100767","DOIUrl":"10.1016/j.pacs.2025.100767","url":null,"abstract":"<div><div>A topological optimization method for photoacoustic resonators is proposed as the Method of Moving Asymptotes with Bernstein Polynomials (MMA-BP). This method is demonstrated in a ppt-level ultra-sensitive photoacoustic spectroscopy gas sensor using miniaturized vase-type photoacoustic cell (V-PAC). The V-PAC has a volume of merely 5 mL and achieves a minimum detection limit of 281 ppt for C<sub>2</sub>H<sub>2</sub> with an integration time of 768 s, corresponding to a normalized noise equivalent absorption of 4.46 × 10⁻<sup>9</sup>∙cm⁻<sup>1</sup>∙Hz⁻<sup>1/2</sup> with a single optical path. It represents an improvement of approximately 14 times beyond that of using the conventional T-type PAC. We experimentally investigated consequent frequency shifts within conventional PACs with thin resonator tubes, and determined the influence of losses on the resonant frequency shift. The geometric contraction effect in vase-type PAC is also investigated. The proposed topological MMA-BP method and implementations provide a universal approach to establish optimized PAC structures for photoacoustic gas detection.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"46 ","pages":"Article 100767"},"PeriodicalIF":6.8,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145010867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-22DOI: 10.1016/j.pacs.2025.100763
Cayla A. Wood , Claire E. Jones , Ananthakrishnan Soundaram Jeevarathinam, Riley Watson, Sangheon Han, Jennifer Meyer, Konstantin V. Sokolov, Richard R. Bouchard
Liposomal carriers, used for site-specific drug delivery, are being investigated for diagnostic approaches by replacing the therapeutic with an imaging contrast agent, exploring potential for selective treatment planning. There remains a critical need to improve in vivo assessment of biodistribution, stability, and clearance kinetics of liposomal carriers. This pilot study presents a multimodal approach in which liposome-encapsulated J-aggregated indocyanine green (ICG) dye (Lipo-JICG) is imaged with high spatial resolution using both in vivo photoacoustic (PA) imaging, to assess the absorbance characteristics of JICG and monomeric ICG, and ex vivo cryofluorescence tomography (CFT), to measure ICG fluorescence. An in vitro assay comparing the relationship between absorbance and fluorescence of Lipo-JICG and ICG demonstrated that the absorbance peak shifted from 780 to 895 nm as the Lipo-JICG:ICG ratio increased; meanwhile, the fluorescence decreased drastically as the Lipo-JICG:ICG ratio increased, demonstrating that J-aggregation quenches fluorescence. Twelve mice were then PA imaged pre-injection, then up to 6 days after Lipo-JICG injection. Unmixed Lipo-JICG signal peaked at 30 min post-injection in both liver and spleen; unmixed ICG signal peaked post-injection, decreasing over time in both organs and increasing at 6 days in the spleen. With CFT, ICG fluorescence followed a similar trend, with a maximum at 30 min in liver and at 6 days in spleen, implying that Lipo-JICG continued to break down and excrete through the hepatic system over 6 days post-injection. Future studies will continue to develop this methodology to assess biodistribution, stability, and clearance of liposomal carriers in tumor-bearing murine models.
{"title":"A multimodal approach to assess a liposomal carrier’s biodistribution, stability, and clearance","authors":"Cayla A. Wood , Claire E. Jones , Ananthakrishnan Soundaram Jeevarathinam, Riley Watson, Sangheon Han, Jennifer Meyer, Konstantin V. Sokolov, Richard R. Bouchard","doi":"10.1016/j.pacs.2025.100763","DOIUrl":"10.1016/j.pacs.2025.100763","url":null,"abstract":"<div><div>Liposomal carriers, used for site-specific drug delivery, are being investigated for diagnostic approaches by replacing the therapeutic with an imaging contrast agent, exploring potential for selective treatment planning. There remains a critical need to improve <em>in vivo</em> assessment of biodistribution, stability, and clearance kinetics of liposomal carriers. This pilot study presents a multimodal approach in which liposome-encapsulated J-aggregated indocyanine green (ICG) dye (Lipo-JICG) is imaged with high spatial resolution using both <em>in vivo</em> photoacoustic (PA) imaging, to assess the absorbance characteristics of JICG and monomeric ICG, and <em>ex vivo</em> cryofluorescence tomography (CFT), to measure ICG fluorescence. An <em>in vitro</em> assay comparing the relationship between absorbance and fluorescence of Lipo-JICG and ICG demonstrated that the absorbance peak shifted from 780 to 895 nm as the Lipo-JICG:ICG ratio increased; meanwhile, the fluorescence decreased drastically as the Lipo-JICG:ICG ratio increased, demonstrating that J-aggregation quenches fluorescence. Twelve mice were then PA imaged pre-injection, then up to 6 days after Lipo-JICG injection. Unmixed Lipo-JICG signal peaked at 30 min post-injection in both liver and spleen; unmixed ICG signal peaked post-injection, decreasing over time in both organs and increasing at 6 days in the spleen. With CFT, ICG fluorescence followed a similar trend, with a maximum at 30 min in liver and at 6 days in spleen, implying that Lipo-JICG continued to break down and excrete through the hepatic system over 6 days post-injection. Future studies will continue to develop this methodology to assess biodistribution, stability, and clearance of liposomal carriers in tumor-bearing murine models.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"46 ","pages":"Article 100763"},"PeriodicalIF":6.8,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144912183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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