Pub Date : 2026-04-01Epub Date: 2026-01-23DOI: 10.1016/j.pacs.2026.100801
Martin Ryzy , Guqi Yan , Clemens Grünsteidl , Georg Watzl , Kevin Sequoia , Pavel Lapa , Haibo Huang
In inertial confinement fusion experiments hollow, spherical mm-sized capsules are used as a container for nuclear fuel. To achieve maximum implosion efficiency, a perfect capsule geometry is required. This paper presents a wall thickness measurement method based on zero-group velocity guided elastic wave resonances. They are measured with a non-destructive, contactless frequency domain laser ultrasound microscopy system. Wall thickness measurements along the equator of a high-density carbon capsule with a diameter of around and a wall thickness of around excellently agree with infrared interferometry reference measurements. In addition, the multi-resonant nature of a spherical shell is studied by complementing experimental observations with plate dispersion calculations and finite element wave propagation simulations. The presented method is scalable and can be applied to a broad range of target materials, including metals, or metal-doped targets.
{"title":"Frequency domain laser ultrasound for inertial confinement fusion target wall thickness measurements","authors":"Martin Ryzy , Guqi Yan , Clemens Grünsteidl , Georg Watzl , Kevin Sequoia , Pavel Lapa , Haibo Huang","doi":"10.1016/j.pacs.2026.100801","DOIUrl":"10.1016/j.pacs.2026.100801","url":null,"abstract":"<div><div>In inertial confinement fusion experiments hollow, spherical mm-sized capsules are used as a container for nuclear fuel. To achieve maximum implosion efficiency, a perfect capsule geometry is required. This paper presents a wall thickness measurement method based on zero-group velocity guided elastic wave resonances. They are measured with a non-destructive, contactless frequency domain laser ultrasound microscopy system. Wall thickness measurements along the equator of a high-density carbon capsule with a diameter of around <span><math><mrow><mn>2</mn><mspace></mspace><mstyle><mi>m</mi><mi>m</mi></mstyle></mrow></math></span> and a wall thickness of around <span><math><mrow><mn>80</mn><mspace></mspace><mstyle><mi>µ</mi><mi>m</mi></mstyle></mrow></math></span> excellently agree with infrared interferometry reference measurements. In addition, the multi-resonant nature of a spherical shell is studied by complementing experimental observations with plate dispersion calculations and finite element wave propagation simulations. The presented method is scalable and can be applied to a broad range of target materials, including metals, or metal-doped targets.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"48 ","pages":"Article 100801"},"PeriodicalIF":6.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039603","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 : 2026-04-01Epub Date: 2026-01-23DOI: 10.1016/j.pacs.2026.100802
Surui Liu, Lu Qin, Chongqiu Zhou, Juncheng Lu, Wen Liu, Jie Shao
This paper presents a method for real-time measurement of in vivo leaves photosynthetic rates using quartz-enhanced photoacoustic spectroscopy (QEPAS) with first-harmonic frequency- locking (1f-locking). A compact gas sensor structure was constructed by integrating an in-plane acoustic micro-resonator (AmR) with a commercial 30.720 kHz quartz tuning fork (QTF). The DFB laser’s output wavelength was locked to the CO2 absorption line at 4991.26 cm−1 via 1f-locking, enabling real-time monitoring of CO2 uptake during leaf photosynthesis. Compared to the scanning mode, the standard deviation (STD) in 1f-locking mode is significantly reduced, with detection sensitivity increased by nearly threefold. The system achieved a 1 s measurement cycle, with detection linearity R2 = 0.999. When the integration time is 127 s, the minimum detection limit (MDL) is 2.44 ppmv. The normalized noise equivalent absorption coefficient (NNEA) is 4.78 × 10−9 cm−1·W·Hz−1/2. Results obtained align with reported photosynthetic rate ranges, validating the system’s feasibility. This system provides a portable, highly sensitive, rapid, and reliable method for leaves photosynthetic rate determination.
{"title":"Real-time in Vivo monitoring of photosynthesis in individual leaves by frequency-locked quartz-enhanced photoacoustic spectroscopy","authors":"Surui Liu, Lu Qin, Chongqiu Zhou, Juncheng Lu, Wen Liu, Jie Shao","doi":"10.1016/j.pacs.2026.100802","DOIUrl":"10.1016/j.pacs.2026.100802","url":null,"abstract":"<div><div>This paper presents a method for real-time measurement of <em>in vivo</em> leaves photosynthetic rates using quartz-enhanced photoacoustic spectroscopy (QEPAS) with first-harmonic frequency- locking (1f-locking). A compact gas sensor structure was constructed by integrating an in-plane acoustic micro-resonator (AmR) with a commercial 30.720 kHz quartz tuning fork (QTF). The DFB laser’s output wavelength was locked to the CO<sub>2</sub> absorption line at 4991.26 cm<sup>−1</sup> via 1f-locking, enabling real-time monitoring of CO<sub>2</sub> uptake during leaf photosynthesis. Compared to the scanning mode, the standard deviation (STD) in 1f-locking mode is significantly reduced, with detection sensitivity increased by nearly threefold. The system achieved a 1 s measurement cycle, with detection linearity R<sup>2</sup> = 0.999. When the integration time is 127 s, the minimum detection limit (MDL) is 2.44 ppmv. The normalized noise equivalent absorption coefficient (NNEA) is 4.78 × 10<sup>−9</sup> cm<sup>−1</sup>·W·Hz<sup>−1/2</sup>. Results obtained align with reported photosynthetic rate ranges, validating the system’s feasibility. This system provides a portable, highly sensitive, rapid, and reliable method for leaves photosynthetic rate determination.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"48 ","pages":"Article 100802"},"PeriodicalIF":6.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039604","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}
In clinical practice, the prompt and accurate identification of acute fetal distress (AFD) is critical. Although cardiotocography and ultrasonography are the cornerstone clinical tools for fetal monitoring, they cannot quantitatively assess fetal cerebral hypoxia and carry inherent risks of underdiagnosis or false-positive interpretations. This study evaluates photoacoustic imaging (PAI) for early AFD detection. In mouse models, oxygen saturation (sO2) in the fetal brain and placenta was measured using PAI, demonstrating a significant sO2 decrease following placental blood flow obstruction - with more pronounced reductions observed in complete versus partial restriction cases. Crucially, a novel two-step PAI approach differentiated placental hypoperfusion from umbilical cord obstruction by analyzing distinct sO2 patterns in both placenta and fetal brain tissues. This distinction is clinically vital, as placental and cord-related AFD require different urgent interventions. PAI’s ability to pinpoint the underlying cause highlights its potential for guiding precise treatment decisions.
{"title":"Early identification of umbilical blood flow restriction and maternal placental hypoperfusion with photoacoustic imaging","authors":"Luting Zhang , Mengyu Zhou , Qiufang Ouyang , Fan Meng , Zhen Yuan , Min Chen , Zongjie Weng , Jian Zhang","doi":"10.1016/j.pacs.2026.100803","DOIUrl":"10.1016/j.pacs.2026.100803","url":null,"abstract":"<div><div>In clinical practice, the prompt and accurate identification of acute fetal distress (AFD) is critical. Although cardiotocography and ultrasonography are the cornerstone clinical tools for fetal monitoring, they cannot quantitatively assess fetal cerebral hypoxia and carry inherent risks of underdiagnosis or false-positive interpretations. This study evaluates photoacoustic imaging (PAI) for early AFD detection. In mouse models, oxygen saturation (sO<sub>2</sub>) in the fetal brain and placenta was measured using PAI, demonstrating a significant sO<sub>2</sub> decrease following placental blood flow obstruction - with more pronounced reductions observed in complete versus partial restriction cases. Crucially, a novel two-step PAI approach differentiated placental hypoperfusion from umbilical cord obstruction by analyzing distinct sO<sub>2</sub> patterns in both placenta and fetal brain tissues. This distinction is clinically vital, as placental and cord-related AFD require different urgent interventions. PAI’s ability to pinpoint the underlying cause highlights its potential for guiding precise treatment decisions.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"48 ","pages":"Article 100803"},"PeriodicalIF":6.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080584","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 : 2026-04-01Epub Date: 2026-01-13DOI: 10.1016/j.pacs.2026.100798
Ahmed Al Fuwaires , Peter Lukacs , Don Pieris , Geo Davis , Helen Mulvana , Katherine Tant , Theodosia Stratoudaki
Speed of sound (SoS) mapping provides quantitative and localised information about a material’s acoustic properties, allowing identification of spatial compositional changes. In biomedical applications, SoS variations can inform tissue characterisation or improve image reconstruction algorithms that typically assume a constant SoS. However, conventional time-of-flight (ToF) tomography methods remain computationally intensive. This study presents experimentally derived tomographic reconstructions of SoS maps of heterogeneous structures from all-optically acquired data using a convolutional neural network (CNN). The CNN, trained on simulated data, enables near real-time, high-quality tomographic reconstructions. The novelty of this work lies in the integration of a laser ultrasound (LU) data acquisition setup with a CNN-based reconstruction approach, demonstrating its potential for remote and flexible inspection of biomedically relevant samples. The CNN was trained using simulated data based on ultrasonic wave propagation models and achieved tomographic reconstructions of a 77 mm 77 mm area in less than 6 ms. Data were acquired from four tissue-mimicking phantoms (30 mm diameter) with inclusions of varying size (minimum 6 mm diameter) and SoS (minimum variation 25 m/s). When compared with published, in vivo studies using mammography (MM), conventional ultrasound, and magnetic resonance imaging (MRI), the proposed method yielded 5.73% mean sizing error for phantoms and inclusions relative to the ground truth, highlighting the clinical potential of the LU-CNN framework and the need for further in vivo testing. These findings underscore the method’s potential as a precise, faster alternative to conventional imaging and reconstruction methods used in clinical practice.
{"title":"Neural networks for faster laser ultrasound tomography in tissue phantoms","authors":"Ahmed Al Fuwaires , Peter Lukacs , Don Pieris , Geo Davis , Helen Mulvana , Katherine Tant , Theodosia Stratoudaki","doi":"10.1016/j.pacs.2026.100798","DOIUrl":"10.1016/j.pacs.2026.100798","url":null,"abstract":"<div><div>Speed of sound (SoS) mapping provides quantitative and localised information about a material’s acoustic properties, allowing identification of spatial compositional changes. In biomedical applications, SoS variations can inform tissue characterisation or improve image reconstruction algorithms that typically assume a constant SoS. However, conventional time-of-flight (ToF) tomography methods remain computationally intensive. This study presents experimentally derived tomographic reconstructions of SoS maps of heterogeneous structures from all-optically acquired data using a convolutional neural network (CNN). The CNN, trained on simulated data, enables near real-time, high-quality tomographic reconstructions. The novelty of this work lies in the integration of a laser ultrasound (LU) data acquisition setup with a CNN-based reconstruction approach, demonstrating its potential for remote and flexible inspection of biomedically relevant samples. The CNN was trained using simulated data based on ultrasonic wave propagation models and achieved tomographic reconstructions of a 77 mm <span><math><mo>×</mo></math></span> 77 mm area in less than 6 ms. Data were acquired from four tissue-mimicking phantoms (30 mm diameter) with inclusions of varying size (minimum 6 mm diameter) and SoS (minimum variation 25 m/s). When compared with published, in vivo studies using mammography (MM), conventional ultrasound, and magnetic resonance imaging (MRI), the proposed method yielded 5.73% mean sizing error for phantoms and inclusions relative to the ground truth, highlighting the clinical potential of the LU-CNN framework and the need for further in vivo testing. These findings underscore the method’s potential as a precise, faster alternative to conventional imaging and reconstruction methods used in clinical practice.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"48 ","pages":"Article 100798"},"PeriodicalIF":6.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190384","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 : 2026-04-01Epub Date: 2026-02-06DOI: 10.1016/j.pacs.2026.100809
Nikita Kaydanov , Magdalena Olesińska-Mönch , Morgane Leite, Robert Prevedel, Claire Deo
Fluorescence and photoacoustic imaging are complementary modalities that provide distinct advantages for biological imaging: fluorescence microscopy offers high sensitivity and resolution, while photoacoustic imaging enables deeper penetration in complex tissue. Leveraging the strengths of both modalities through optically switchable contrast agents can offer enhanced imaging contrast and facilitate dual-modality imaging. Here, we report a photoswitchable probe capable of toggling between high fluorescence and high photoacoustic signal upon illumination, exploiting Förster Resonance Energy Transfer (FRET). We engineer novel spironaphtopyran photoswitches which undergo reversible photoisomerization between absorbing and non-absorbing states. Their photoswitching properties were systematically characterized, establishing structure-properties relationships, and providing the first photoacoustic investigation into this class of compounds. The best-performing switch was incorporated into a FRET dyad with a rhodamine fluorophore, which exhibits robust, reversible switching between fluorescent and photoacoustic-dominant states with excellent contrast in vitro, establishing a foundation for multimodal imaging probes with promising potential for dynamic correlative imaging.
{"title":"Bridging light and sound: A spironaphtopyran-rhodamine dyad with high-contrast photoswitching between fluorescence and photoacoustic signal","authors":"Nikita Kaydanov , Magdalena Olesińska-Mönch , Morgane Leite, Robert Prevedel, Claire Deo","doi":"10.1016/j.pacs.2026.100809","DOIUrl":"10.1016/j.pacs.2026.100809","url":null,"abstract":"<div><div>Fluorescence and photoacoustic imaging are complementary modalities that provide distinct advantages for biological imaging: fluorescence microscopy offers high sensitivity and resolution, while photoacoustic imaging enables deeper penetration in complex tissue. Leveraging the strengths of both modalities through optically switchable contrast agents can offer enhanced imaging contrast and facilitate dual-modality imaging. Here, we report a photoswitchable probe capable of toggling between high fluorescence and high photoacoustic signal upon illumination, exploiting Förster Resonance Energy Transfer (FRET). We engineer novel spironaphtopyran photoswitches which undergo reversible photoisomerization between absorbing and non-absorbing states. Their photoswitching properties were systematically characterized, establishing structure-properties relationships, and providing the first photoacoustic investigation into this class of compounds. The best-performing switch was incorporated into a FRET dyad with a rhodamine fluorophore, which exhibits robust, reversible switching between fluorescent and photoacoustic-dominant states with excellent contrast <em>in vitro</em>, establishing a foundation for multimodal imaging probes with promising potential for dynamic correlative imaging.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"48 ","pages":"Article 100809"},"PeriodicalIF":6.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190381","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 : 2026-04-01Epub Date: 2026-01-30DOI: 10.1016/j.pacs.2026.100804
Xuanhao Zhang , Zheng Qu , Bin Ouyang , Lidai Wang
Photoacoustic computed tomography (PACT) reconstructs high-resolution images of various chromophores in deep biological tissue. A key to high-quality reconstruction is accurate compensation for the spatially heterogeneous speed of sound (SoS) in tissue. Existing computational methods often estimate or compensate SoS by tuning it directly in the image domain, for example by optimizing sharpness or contrast of reconstructed PA images. However, because the PA signal-to-noise ratio (SNR) decays rapidly with depth due to optical attenuation, such image-domain cues become less informative in deeper regions, limiting SoS accuracy there. Here, we present a dual-modal deep learning framework to correct the heterogeneous SoS via joint processing co-registered PA and ultrasound (US) images. We estimate the spatially varying SoS map from the US image and then fuse the SoS map with the PA image to compute a reduced-aberration photoacoustic image. This method takes advantages of the rich speckle and high SNR in the co-registered US image – and thus can compensate for SoS with high accuracy and efficiency. We tested this method on numerical and tissue-mimicking phantoms, demonstrating cross-domain generalization. In-vivo results demonstrate that incorporation of the predicted SoS maps significantly improved PA image quality, enhancing structural detail and reducing acoustic artifacts. Via fusing the US and PA images, our method produces high-contrast PA images with significantly reduced SoS distortion and artifacts.
{"title":"Ultrasound-guided sound speed correction for photoacoustic computed tomography","authors":"Xuanhao Zhang , Zheng Qu , Bin Ouyang , Lidai Wang","doi":"10.1016/j.pacs.2026.100804","DOIUrl":"10.1016/j.pacs.2026.100804","url":null,"abstract":"<div><div>Photoacoustic computed tomography (PACT) reconstructs high-resolution images of various chromophores in deep biological tissue. A key to high-quality reconstruction is accurate compensation for the spatially heterogeneous speed of sound (SoS) in tissue. Existing computational methods often estimate or compensate SoS by tuning it directly in the image domain, for example by optimizing sharpness or contrast of reconstructed PA images. However, because the PA signal-to-noise ratio (SNR) decays rapidly with depth due to optical attenuation, such image-domain cues become less informative in deeper regions, limiting SoS accuracy there. Here, we present a dual-modal deep learning framework to correct the heterogeneous SoS via joint processing co-registered PA and ultrasound (US) images. We estimate the spatially varying SoS map from the US image and then fuse the SoS map with the PA image to compute a reduced-aberration photoacoustic image. This method takes advantages of the rich speckle and high SNR in the co-registered US image – and thus can compensate for SoS with high accuracy and efficiency. We tested this method on numerical and tissue-mimicking phantoms, demonstrating cross-domain generalization. In-vivo results demonstrate that incorporation of the predicted SoS maps significantly improved PA image quality, enhancing structural detail and reducing acoustic artifacts. Via fusing the US and PA images, our method produces high-contrast PA images with significantly reduced SoS distortion and artifacts.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"48 ","pages":"Article 100804"},"PeriodicalIF":6.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146183546","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 : 2026-04-01Epub Date: 2026-02-02DOI: 10.1016/j.pacs.2026.100805
Yubing Yang , Xukun Yin , Xiu Yang , Weizhun Dong , Jianyu Gu , Jinxu Yang , Wenxuan Zhao , Kai Liu , Guolin Li
Helicobacter pylori infection is closely associated with chronic gastritis, peptic ulcers, and gastric cancer, rendering rapid and noninvasive diagnostic technologies clinically essential. Current breath tests, such as the 13C-urea breath test (13C-UBT), typically rely on breath collection bags followed by offline analysis, which limits real-time monitoring capabilities. To overcome this constraint, we presented a mid-infrared photoacoustic spectroscopy (MIR-PAS) system for real-time detection of CO2 isotopes and evaluation of 13C-UBT responses. A dual-channel differential resonant photoacoustic cell (DPAC) with a minimal sample volume of 10.3 mL was designed to enhance acoustic signal collection, achieving a resonance frequency of 3775.7 Hz and a Q-factor of 27. Target absorption lines of 12CO2 (2299.64 cm-¹) and 13CO2 (2299.80 cm-¹) were selected within the strong ν3 band to ensure high-resolution isotopic discrimination using a 4.35 μm quantum cascade laser. The sensor demonstrated excellent linear response (R2 > 0.994) across 500–2500 ppm and achieved detection limits of 8.98 ppb for 12CO2 and 2.81 ppb for 13CO2 with the optimal averaging. δ13C measurements exhibited a precision of 0.066 ‰ at 76 s averaging time. Breath-sampling tests further revealed distinct temporal release patterns of CO2 isotopes during exhalation. These results confirmed that the developed MIR-PAS system provides a compact, sensitive, and robust platform for isotopic CO2 analysis and demonstrates strong potential for point-of-care H. pylori diagnostics.
{"title":"A Ppb-level MIR-PAS for 12CO2/13CO2 isotope analysis toward on-line breath-based H. pylori sensing","authors":"Yubing Yang , Xukun Yin , Xiu Yang , Weizhun Dong , Jianyu Gu , Jinxu Yang , Wenxuan Zhao , Kai Liu , Guolin Li","doi":"10.1016/j.pacs.2026.100805","DOIUrl":"10.1016/j.pacs.2026.100805","url":null,"abstract":"<div><div>Helicobacter pylori infection is closely associated with chronic gastritis, peptic ulcers, and gastric cancer, rendering rapid and noninvasive diagnostic technologies clinically essential. Current breath tests, such as the <sup>13</sup>C-urea breath test (<sup>13</sup>C-UBT), typically rely on breath collection bags followed by offline analysis, which limits real-time monitoring capabilities. To overcome this constraint, we presented a mid-infrared photoacoustic spectroscopy (MIR-PAS) system for real-time detection of CO<sub>2</sub> isotopes and evaluation of <sup>13</sup>C-UBT responses. A dual-channel differential resonant photoacoustic cell (DPAC) with a minimal sample volume of 10.3 mL was designed to enhance acoustic signal collection, achieving a resonance frequency of 3775.7 Hz and a <em>Q</em>-factor of 27. Target absorption lines of <sup>12</sup>CO<sub>2</sub> (2299.64 cm<sup>-</sup>¹) and <sup>13</sup>CO<sub>2</sub> (2299.80 cm<sup>-</sup>¹) were selected within the strong ν<sub>3</sub> band to ensure high-resolution isotopic discrimination using a 4.35 μm quantum cascade laser. The sensor demonstrated excellent linear response (R<sup>2</sup> > 0.994) across 500–2500 ppm and achieved detection limits of 8.98 ppb for <sup>12</sup>CO<sub>2</sub> and 2.81 ppb for <sup>13</sup>CO<sub>2</sub> with the optimal averaging. δ<sup>13</sup>C measurements exhibited a precision of 0.066 ‰ at 76 s averaging time. Breath-sampling tests further revealed distinct temporal release patterns of CO<sub>2</sub> isotopes during exhalation. These results confirmed that the developed MIR-PAS system provides a compact, sensitive, and robust platform for isotopic CO<sub>2</sub> analysis and demonstrates strong potential for point-of-care H. pylori diagnostics.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"48 ","pages":"Article 100805"},"PeriodicalIF":6.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190382","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 : 2026-04-01Epub Date: 2025-12-29DOI: 10.1016/j.pacs.2025.100792
Refik Mert Cam , Seonyeong Park , Umberto Villa , Mark A. Anastasio
Quantitative photoacoustic computed tomography (qPACT) is a promising imaging modality for estimating physiological parameters such as blood oxygen saturation. However, developing robust qPACT reconstruction methods remains challenging due to computational demands, modeling difficulties, and experimental uncertainties. Learning-based methods have been proposed to address these issues but remain largely unvalidated. Virtual imaging (VI) studies are essential for validating such methods early in development, before proceeding to less-controlled phantom or in vivo studies. Effective VI studies must employ ensembles of stochastically generated numerical phantoms that accurately reflect relevant anatomy and physiology. Yet, most prior VI studies for qPACT relied on overly simplified phantoms. In this work, a realistic VI testbed is employed for the first time to assess a representative 3D learning-based qPACT reconstruction method for breast imaging. The method is evaluated across subject variability and physical factors such as measurement noise and acoustic aberrations, offering insights into its strengths and limitations.
{"title":"Application of a virtual imaging framework for investigating a deep learning-based reconstruction method for 3D quantitative photoacoustic computed tomography","authors":"Refik Mert Cam , Seonyeong Park , Umberto Villa , Mark A. Anastasio","doi":"10.1016/j.pacs.2025.100792","DOIUrl":"10.1016/j.pacs.2025.100792","url":null,"abstract":"<div><div>Quantitative photoacoustic computed tomography (qPACT) is a promising imaging modality for estimating physiological parameters such as blood oxygen saturation. However, developing robust qPACT reconstruction methods remains challenging due to computational demands, modeling difficulties, and experimental uncertainties. Learning-based methods have been proposed to address these issues but remain largely unvalidated. Virtual imaging (VI) studies are essential for validating such methods early in development, before proceeding to less-controlled phantom or in vivo studies. Effective VI studies must employ ensembles of stochastically generated numerical phantoms that accurately reflect relevant anatomy and physiology. Yet, most prior VI studies for qPACT relied on overly simplified phantoms. In this work, a realistic VI testbed is employed for the first time to assess a representative 3D learning-based qPACT reconstruction method for breast imaging. The method is evaluated across subject variability and physical factors such as measurement noise and acoustic aberrations, offering insights into its strengths and limitations.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"48 ","pages":"Article 100792"},"PeriodicalIF":6.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146001786","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 : 2026-04-01Epub Date: 2026-02-04DOI: 10.1016/j.pacs.2026.100808
Tianqu Zhai , Wei Zhang , Chenshuo Ma , Linyu Ni , Yannis M. Paulus , Enming Joseph Su , Geoffrey G. Murphy , Daniel A. Lawrence , Xueding Wang
This study introduces a method for longitudinally monitoring Alzheimer’s disease (AD)-related biomarkers in a rodent model utilizing a dual-modality imaging system combining photoacoustic microscopy (PAM) and confocal fluorescence microscopy (CFM). Using a cranial window transparent to both light and ultrasound, we examined cerebral vasculature, blood flow speed, oxygen saturation (sO2), and amyloid-β (Aβ) deposition with single capillary resolution in genetically modified AD mice longitudinally over three months. Empowered by the high-resolution multimodal imaging, the analysis showed consistent changes of small vessel density decrease and Aβ deposition increase in AD mice compared to the control group. Meanwhile, a decrease in sO2 was observed in AD group near the end of the observation period, highlighting the potential importance of functional imaging of hemodynamics that PAM facilitates. This multimodal system, with its longitudinal imaging capability, could provide valuable insight into the temporal dynamics and interrelationships of multiple biomarkers in neurodegenerative diseases.
本研究介绍了一种利用结合光声显微镜（PAM）和共聚焦荧光显微镜（CFM）的双模成像系统，在啮齿动物模型中纵向监测阿尔茨海默病（AD）相关生物标志物的方法。我们使用一个对光和超声都透明的颅窗，用单毛细血管分辨率纵向检查了转基因AD小鼠的脑血管系统、血流速度、氧饱和度（sO2）和淀粉样蛋白-β (a β)沉积，时间超过三个月。在高分辨率多模态成像的支持下，分析显示与对照组相比，AD小鼠的小血管密度降低，Aβ沉积增加。同时，AD组在接近观察期结束时观察到sO2下降，突出了PAM促进的血流动力学功能成像的潜在重要性。这种具有纵向成像能力的多模式系统可以为神经退行性疾病中多种生物标志物的时间动态和相互关系提供有价值的见解。
{"title":"Multi-parametric longitudinal imaging of cerebral biomarkers in a rodent model of Alzheimer’s disease","authors":"Tianqu Zhai , Wei Zhang , Chenshuo Ma , Linyu Ni , Yannis M. Paulus , Enming Joseph Su , Geoffrey G. Murphy , Daniel A. Lawrence , Xueding Wang","doi":"10.1016/j.pacs.2026.100808","DOIUrl":"10.1016/j.pacs.2026.100808","url":null,"abstract":"<div><div>This study introduces a method for longitudinally monitoring Alzheimer’s disease (AD)-related biomarkers in a rodent model utilizing a dual-modality imaging system combining photoacoustic microscopy (PAM) and confocal fluorescence microscopy (CFM). Using a cranial window transparent to both light and ultrasound, we examined cerebral vasculature, blood flow speed, oxygen saturation (sO<sub>2</sub>), and amyloid-β (Aβ) deposition with single capillary resolution in genetically modified AD mice longitudinally over three months. Empowered by the high-resolution multimodal imaging, the analysis showed consistent changes of small vessel density decrease and Aβ deposition increase in AD mice compared to the control group. Meanwhile, a decrease in sO<sub>2</sub> was observed in AD group near the end of the observation period, highlighting the potential importance of functional imaging of hemodynamics that PAM facilitates. This multimodal system, with its longitudinal imaging capability, could provide valuable insight into the temporal dynamics and interrelationships of multiple biomarkers in neurodegenerative diseases.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"48 ","pages":"Article 100808"},"PeriodicalIF":6.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190383","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}
Subcutaneous adipose tissue (SAT) hemodynamics is an indicator of cardiometabolic health. Herein, we demonstrate a non-invasive approach for imaging SAT hemodynamics in humans using multispectral optoacoustic tomography (MSOT). We evaluated different SAT depots in individuals with low (< 24 kg/m²) and high (≥ 24 kg/m²) BMI, with each group consisting of 8 participants, during oral glucose challenges. Our results indicate a significant decrease in glucose-induced hyperemic responses within SAT for individuals with higher BMI, at 60 min postprandially. MSOT also revealed that abdominal SAT exhibited a more active hemodynamic status compared to femoral SAT in both groups when compared to baseline measurements. MSOT readouts were further validated against longitudinal blood tests of triglycerides, glucose, lactate, and cholesterol. We introduce MSOT as a new method for studying SAT hemodynamics across multiple depots in a single test, providing invaluable insights into SAT physiology related to BMI fluctuations and general cardiometabolic health.
{"title":"Mapping glucose-induced hemodynamics in white fat depots with label-free optoacoustics","authors":"Nikolina-Alexia Fasoula , Nikoletta Katsouli , Michael Kallmayer , Vasilis Ntziachristos , Angelos Karlas","doi":"10.1016/j.pacs.2025.100793","DOIUrl":"10.1016/j.pacs.2025.100793","url":null,"abstract":"<div><div>Subcutaneous adipose tissue (SAT) hemodynamics is an indicator of cardiometabolic health. Herein, we demonstrate a non-invasive approach for imaging SAT hemodynamics in humans using multispectral optoacoustic tomography (MSOT). We evaluated different SAT depots in individuals with low (< 24 kg/m²) and high (≥ 24 kg/m²) BMI, with each group consisting of 8 participants, during oral glucose challenges. Our results indicate a significant decrease in glucose-induced hyperemic responses within SAT for individuals with higher BMI, at 60 min postprandially. MSOT also revealed that abdominal SAT exhibited a more active hemodynamic status compared to femoral SAT in both groups when compared to baseline measurements. MSOT readouts were further validated against longitudinal blood tests of triglycerides, glucose, lactate, and cholesterol. We introduce MSOT as a new method for studying SAT hemodynamics across multiple depots in a single test, providing invaluable insights into SAT physiology related to BMI fluctuations and general cardiometabolic health.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"47 ","pages":"Article 100793"},"PeriodicalIF":6.8,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037847","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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