Pub Date : 2025-02-01DOI: 10.1016/j.pacs.2024.100675
Yixiao Lin , Quing Zhu
Ovarian-adnexal lesions are conventionally assessed with ultrasound (US) under the guidance of the Ovarian-Adnexal Reporting and Data System (O-RADS). However, the low specificity of O-RADS results in many unnecessary surgeries. Here, we use co-registered US and photoacoustic tomography (PAT) to improve the diagnostic accuracy of O-RADS. Physics-based parametric algorithms for US and PAT were developed to estimate the acoustic and photoacoustic properties of 93 ovarian lesions. Additionally, statistics-based radiomic algorithms were applied to quantify differences in the lesion texture on US-PAT images. A machine learning model (US-PAT KNN model) was developed based on an optimized subset of eight US and PAT imaging features to classify a lesion as either cancer, one of four subtypes of benign lesions, or a normal ovary. The model achieved an area under the receiver operating characteristic curve (AUC) of 0.969 and a balanced six-class classification accuracy of 86.0 %.
{"title":"Classification and risk assessment of ovarian-adnexal lesions using parametric and radiomic analysis of co-registered ultrasound-photoacoustic tomographic images","authors":"Yixiao Lin , Quing Zhu","doi":"10.1016/j.pacs.2024.100675","DOIUrl":"10.1016/j.pacs.2024.100675","url":null,"abstract":"<div><div>Ovarian-adnexal lesions are conventionally assessed with ultrasound (US) under the guidance of the Ovarian-Adnexal Reporting and Data System (O-RADS). However, the low specificity of O-RADS results in many unnecessary surgeries. Here, we use co-registered US and photoacoustic tomography (PAT) to improve the diagnostic accuracy of O-RADS. Physics-based parametric algorithms for US and PAT were developed to estimate the acoustic and photoacoustic properties of 93 ovarian lesions. Additionally, statistics-based radiomic algorithms were applied to quantify differences in the lesion texture on US-PAT images. A machine learning model (US-PAT KNN model) was developed based on an optimized subset of eight US and PAT imaging features to classify a lesion as either cancer, one of four subtypes of benign lesions, or a normal ovary. The model achieved an area under the receiver operating characteristic curve (AUC) of 0.969 and a balanced six-class classification accuracy of 86.0 %.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"41 ","pages":"Article 100675"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11664067/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142883625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.pacs.2024.100679
Liangjie Wang , Yi-Chao Meng , Yiming Qian
Photoacoustic imaging (PAI) is an emerging hybrid imaging technology that combines the advantages of optical and ultrasound imaging. Despite its excellent imaging capabilities, PAI still faces numerous challenges in clinical applications, particularly sparse spatial sampling and limited view detection. These limitations often result in severe streak artifacts and blurring when using standard methods to reconstruct images from incomplete data. In this work, we propose an improved convolutional neural network (CNN) architecture, called multi-scale dense UNet (MSD-Net), to correct artifacts in 2D photoacoustic tomography (PAT). MSD-Net exploits the advantages of multi-scale information fusion and dense connections to improve the performance of CNN. Experimental validation with both simulated and in vivo datasets demonstrates that our method achieves better reconstructions with improved speed.
{"title":"MSD-Net: Multi-scale dense convolutional neural network for photoacoustic image reconstruction with sparse data","authors":"Liangjie Wang , Yi-Chao Meng , Yiming Qian","doi":"10.1016/j.pacs.2024.100679","DOIUrl":"10.1016/j.pacs.2024.100679","url":null,"abstract":"<div><div>Photoacoustic imaging (PAI) is an emerging hybrid imaging technology that combines the advantages of optical and ultrasound imaging. Despite its excellent imaging capabilities, PAI still faces numerous challenges in clinical applications, particularly sparse spatial sampling and limited view detection. These limitations often result in severe streak artifacts and blurring when using standard methods to reconstruct images from incomplete data. In this work, we propose an improved convolutional neural network (CNN) architecture, called multi-scale dense UNet (MSD-Net), to correct artifacts in 2D photoacoustic tomography (PAT). MSD-Net exploits the advantages of multi-scale information fusion and dense connections to improve the performance of CNN. Experimental validation with both simulated and <em>in vivo</em> datasets demonstrates that our method achieves better reconstructions with improved speed.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"41 ","pages":"Article 100679"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11720879/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142973422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.pacs.2024.100672
Feihu Fang , Runqiu Wang , Dongfang Shao , Yi Wang , Yilü Tao , Shengshou Lin , Yufei Ma , Jinxing Liang
The quartz tuning fork (QTF) being the acoustic-electrical conversion element for quartz-enhanced photoacoustic spectroscopy (QEPAS) system directly affects the detection sensitivity. However, the low electromechanical conversion efficiency characteristic of standard QTF limits the further enhancement of the system. Therefore, the optimized design for QTF is becoming an important approach to improve the performance of QEPAS. In this work, 9 kHz T-shaped QTFs with isosceles-trapezoidal grooves are firstly applied to gas sensing experiments. Four types of 9 kHz QTFs are fabricated and applied to gas detection experiments. Simulation results reveal QTFs with isosceles-trapezoidal grooves are conducive to optimizing the stress distribution and enhancing electromechanical conversion efficiency. The results of the gas sensing experiment (acetylene C2H2) indicate that the signal peak and signal-to-noise ratio values of T-shaped QTF with positive isosceles-trapezoidal grooves can reach 1.44 and 1.85 times greater than the normal QTF with rectangular cross-section prongs.
{"title":"Improved T-shaped quartz tuning fork with isosceles-trapezoidal grooves optimized for quartz-enhanced photoacoustic spectroscopy","authors":"Feihu Fang , Runqiu Wang , Dongfang Shao , Yi Wang , Yilü Tao , Shengshou Lin , Yufei Ma , Jinxing Liang","doi":"10.1016/j.pacs.2024.100672","DOIUrl":"10.1016/j.pacs.2024.100672","url":null,"abstract":"<div><div>The quartz tuning fork (QTF) being the acoustic-electrical conversion element for quartz-enhanced photoacoustic spectroscopy (QEPAS) system directly affects the detection sensitivity. However, the low electromechanical conversion efficiency characteristic of standard QTF limits the further enhancement of the system. Therefore, the optimized design for QTF is becoming an important approach to improve the performance of QEPAS. In this work, 9 kHz T-shaped QTFs with isosceles-trapezoidal grooves are firstly applied to gas sensing experiments. Four types of 9 kHz QTFs are fabricated and applied to gas detection experiments. Simulation results reveal QTFs with isosceles-trapezoidal grooves are conducive to optimizing the stress distribution and enhancing electromechanical conversion efficiency. The results of the gas sensing experiment (acetylene C<sub>2</sub>H<sub>2</sub>) indicate that the signal peak and signal-to-noise ratio values of T-shaped QTF with positive isosceles-trapezoidal grooves can reach 1.44 and 1.85 times greater than the normal QTF with rectangular cross-section prongs.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"41 ","pages":"Article 100672"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11652942/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142856955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.pacs.2024.100669
Yifan Li , Lixian Liu , Liang Zhao , Xueshi Zhang , Le Zhang , Jialiang Sun , Huiting Huan , Yize Liang , Jiyong Zhang , Xiaopeng Shao , Andreas Mandelis , Roberto Li Voti
A compact and robust optical excitation photoacoustic sensor with a self-integrated laser module excitation and an optimized differential resonator was developed to achieve high sensitivity and full linear range detection of carbon dioxide (CO2) based on dual modes of wavelength modulated photoacoustic spectroscopy (WMPAS) and resonant frequency tracking (RFT). The integrated laser module equipped with three lasers (a quantum cascade laser (QCL), a distributed feedback laser (DFB) and a He-Ne laser) working in a time-division multiplexing mode was used as an integrated set of spectroscopic sources for detection of the designated concentration levels of CO2. With the absorption photoacoustic mode, the WMPAS detection with the QCL and DFB sources was capable of CO2 detection at concentrations below 20 %, yielding a noise equivalent concentration (NEC) as low as 240 ppt and a normalized noise equivalent absorption coefficient (NNEA) of 4.755 × 10−10 W cm−1/√Hz, and dynamic range as great as 11 orders of magnitude. Higher concentration detection ranges (20 %-100 %) of CO2 were investigated using the RFT mode with an amplitude-stabilized He-Ne laser and a mechanical chopper. With the dual modes of WMPAS and RFT, the optical excitation sensor achieved full-range CO2 detection, with an R² ≥ 0.9993 and a response time of 5 seconds. The compact and full-range CO2 sensor combines the advantages of WMPAS and RFT and offers a solution for high sensitivity, linearity and full-range CO2 detection.
{"title":"Compact and full-range carbon dioxide sensor using photoacoustic and resonance dependent modes","authors":"Yifan Li , Lixian Liu , Liang Zhao , Xueshi Zhang , Le Zhang , Jialiang Sun , Huiting Huan , Yize Liang , Jiyong Zhang , Xiaopeng Shao , Andreas Mandelis , Roberto Li Voti","doi":"10.1016/j.pacs.2024.100669","DOIUrl":"10.1016/j.pacs.2024.100669","url":null,"abstract":"<div><div>A compact and robust optical excitation photoacoustic sensor with a self-integrated laser module excitation and an optimized differential resonator was developed to achieve high sensitivity and full linear range detection of carbon dioxide (CO<sub>2</sub>) based on dual modes of wavelength modulated photoacoustic spectroscopy (WMPAS) and resonant frequency tracking (RFT). The integrated laser module equipped with three lasers (a quantum cascade laser (QCL), a distributed feedback laser (DFB) and a He-Ne laser) working in a time-division multiplexing mode was used as an integrated set of spectroscopic sources for detection of the designated concentration levels of CO<sub>2</sub>. With the absorption photoacoustic mode, the WMPAS detection with the QCL and DFB sources was capable of CO<sub>2</sub> detection at concentrations below 20 %, yielding a noise equivalent concentration (NEC) as low as 240 ppt and a normalized noise equivalent absorption coefficient (NNEA) of 4.755 × 10<sup>−10</sup> W cm<sup>−1</sup>/√Hz, and dynamic range as great as 11 orders of magnitude. Higher concentration detection ranges (20 %-100 %) of CO<sub>2</sub> were investigated using the RFT mode with an amplitude-stabilized He-Ne laser and a mechanical chopper. With the dual modes of WMPAS and RFT, the optical excitation sensor achieved full-range CO<sub>2</sub> detection, with an R² ≥ 0.9993 and a response time of 5 seconds. The compact and full-range CO<sub>2</sub> sensor combines the advantages of WMPAS and RFT and offers a solution for high sensitivity, linearity and full-range CO<sub>2</sub> detection.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"41 ","pages":"Article 100669"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11665709/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142883628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.pacs.2024.100671
Sarah F. Shaykevich , Justin P. Little , Yong Qian , Marie-Eve Paquet , Robert E. Campbell , Daniel Razansky , Shy Shoham
Measuring whole-brain distributed functional activity is an important unmet need in neuroscience, requiring high temporal resolution and cellular specificity across large volumes. Functional optoacoustic neuro-tomography (FONT) with genetically encoded calcium ion indicators is a promising approach towards this goal. However, it has not yet been applied in the near-infrared (NIR) range that provides deep penetration and low vascular background optimal for in vivo neuroimaging. Here, we study the noninvasive multimodal fluorescence and optoacoustic imaging performance of state-of-the-art NIR calcium ion indicator NIR-GECO2G in the mouse brain. We observe robust in vivo signals with widefield fluorescence, and for the first time, with FONT. We also show that in both modalities, the NIR-GECO2G signal improves more than twofold in the biliverdin-enriched Blvra-/- mouse line compared to wild type. Our findings demonstrate the potential of multimodal fluorescence and optoacoustic NIR imaging, opening new possibilities for whole-brain real-time functional imaging in rodents.
测量全脑分布式功能活动是神经科学领域尚未满足的一个重要需求，它要求在大容量范围内具有高时间分辨率和细胞特异性。利用基因编码的钙离子指示剂进行功能性光声神经断层成像（FONT）是实现这一目标的一种很有前景的方法。然而，该技术尚未应用于近红外（NIR）范围，而近红外（NIR）范围具有深穿透性和低血管背景，是体内神经成像的最佳选择。在这里，我们研究了最先进的近红外钙离子指示剂 NIR-GECO2G 在小鼠大脑中的无创多模荧光和光声成像性能。我们用宽场荧光观察到了强大的体内信号，并首次用 FONT 观察到了信号。我们还发现，在这两种模式下，富含胆绿素的 Blvra -/- 小鼠系的近红外-GECO2G 信号比野生型提高了两倍多。我们的研究结果证明了多模式荧光和光声近红外成像的潜力，为啮齿类动物全脑实时功能成像开辟了新的可能性。
{"title":"Multimodal fluorescence-optoacoustic in vivo imaging of the near-infrared calcium ion indicator NIR-GECO2G","authors":"Sarah F. Shaykevich , Justin P. Little , Yong Qian , Marie-Eve Paquet , Robert E. Campbell , Daniel Razansky , Shy Shoham","doi":"10.1016/j.pacs.2024.100671","DOIUrl":"10.1016/j.pacs.2024.100671","url":null,"abstract":"<div><div>Measuring whole-brain distributed functional activity is an important unmet need in neuroscience, requiring high temporal resolution and cellular specificity across large volumes. Functional optoacoustic neuro-tomography (FONT) with genetically encoded calcium ion indicators is a promising approach towards this goal. However, it has not yet been applied in the near-infrared (NIR) range that provides deep penetration and low vascular background optimal for <em>in vivo</em> neuroimaging. Here, we study the noninvasive multimodal fluorescence and optoacoustic imaging performance of state-of-the-art NIR calcium ion indicator NIR-GECO2G in the mouse brain. We observe robust <em>in vivo</em> signals with widefield fluorescence, and for the first time, with FONT. We also show that in both modalities, the NIR-GECO2G signal improves more than twofold in the biliverdin-enriched <em>Blvra</em><sup><em>-/-</em></sup> mouse line compared to wild type. Our findings demonstrate the potential of multimodal fluorescence and optoacoustic NIR imaging, opening new possibilities for whole-brain real-time functional imaging in rodents.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"41 ","pages":"Article 100671"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11732225/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142985603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.pacs.2024.100673
Anjali Thomas , Max Rietberg , Mervenur Akkus , Gijs van Soest , Kalloor Joseph Francis
Photoacoustic imaging offers optical contrast images of human tissue at acoustic resolution, making it valuable for diverse clinical applications. However, quantifying tissue composition via optical contrast remains challenging due to the unknown light fluence within the tissue. Here, we propose a method that leverages known chromophores (e.g., arterial blood) to improve the accuracy of quantitative photoacoustic imaging. By using the optical properties of a known chromophore as a fluence marker and integrating it into the optical inversion process, we can estimate the unknown fluence within the tissue. Experimentally, we demonstrate that this approach successfully recovers both the spectral shape and magnitude of the optical absorption coefficient of an unknown chromophore. Additionally, we show that the fluence marker method enhances conventional optical inversion techniques, specifically (i) a straightforward iterative approach and (ii) a gradient-based method. Our results indicate an improvement in accuracy of up to 24.4% when comparing optical absorption recovery with and without the fluence marker. Finally, we present the method’s performance and illustrate its applications in carotid plaque quantification.
{"title":"Quantitative photoacoustic imaging using known chromophores as fluence marker","authors":"Anjali Thomas , Max Rietberg , Mervenur Akkus , Gijs van Soest , Kalloor Joseph Francis","doi":"10.1016/j.pacs.2024.100673","DOIUrl":"10.1016/j.pacs.2024.100673","url":null,"abstract":"<div><div>Photoacoustic imaging offers optical contrast images of human tissue at acoustic resolution, making it valuable for diverse clinical applications. However, quantifying tissue composition via optical contrast remains challenging due to the unknown light fluence within the tissue. Here, we propose a method that leverages known chromophores (<em>e.g.</em>, arterial blood) to improve the accuracy of quantitative photoacoustic imaging. By using the optical properties of a known chromophore as a fluence marker and integrating it into the optical inversion process, we can estimate the unknown fluence within the tissue. Experimentally, we demonstrate that this approach successfully recovers both the spectral shape and magnitude of the optical absorption coefficient of an unknown chromophore. Additionally, we show that the fluence marker method enhances conventional optical inversion techniques, specifically (i) a straightforward iterative approach and (ii) a gradient-based method. Our results indicate an improvement in accuracy of up to 24.4% when comparing optical absorption recovery with and without the fluence marker. Finally, we present the method’s performance and illustrate its applications in carotid plaque quantification.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"41 ","pages":"Article 100673"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11741946/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143017008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.pacs.2024.100681
Ruiming Wu , Wenjun Ni , Chunyong Yang , Bingze He , Ping Lu , Sixiang Ran , Zhongke Zhao , Perry Ping Shum
A novel balloon-type photoacoustic cell (BTPAC) is proposed to facilitate the detection limitations of acetylene (C2H2) gas achieving ppb level. Here, an ellipsoidal photoacoustic cavity is employed as the platform for gas-light interaction. By strategically directing the excitation source towards the focal point of the ellipsoidal cavity, ensuring its trajectory traverses the focal point upon each reflection from the interior walls. This path increases the gas absorption path length and improves the efficiency of the laser-gas interaction process. Experimental results show that the quality factor of the BTPAC is 224.24 under normal temperature and pressure conditions. Notably, the system maintains a high signal-to-noise ratio even at a C2H2 concentration of 0.1 ppm. Moreover, the minimum detection limit (MDL) and normalized noise equivalent absorption can be calculated to be 3.86 ppb, 6.94·10−10 cm−1·W·Hz−1/2, respectively. Finally, the MDL of the sensor reaches to 0.71 ppb when the integration time reaches 100 s.
{"title":"Multiple optical path length reflections enhancement based on balloon-type photoacoustic cell for trace gas sensing","authors":"Ruiming Wu , Wenjun Ni , Chunyong Yang , Bingze He , Ping Lu , Sixiang Ran , Zhongke Zhao , Perry Ping Shum","doi":"10.1016/j.pacs.2024.100681","DOIUrl":"10.1016/j.pacs.2024.100681","url":null,"abstract":"<div><div>A novel balloon-type photoacoustic cell (BTPAC) is proposed to facilitate the detection limitations of acetylene (C<sub>2</sub>H<sub>2</sub>) gas achieving ppb level. Here, an ellipsoidal photoacoustic cavity is employed as the platform for gas-light interaction. By strategically directing the excitation source towards the focal point of the ellipsoidal cavity, ensuring its trajectory traverses the focal point upon each reflection from the interior walls. This path increases the gas absorption path length and improves the efficiency of the laser-gas interaction process. Experimental results show that the quality factor of the BTPAC is 224.24 under normal temperature and pressure conditions. Notably, the system maintains a high signal-to-noise ratio even at a C<sub>2</sub>H<sub>2</sub> concentration of 0.1 ppm. Moreover, the minimum detection limit (MDL) and normalized noise equivalent absorption can be calculated to be 3.86 ppb, 6.94·10<sup>−10</sup> cm<sup>−1</sup>·W·Hz<sup>−1/2</sup>, respectively. Finally, the MDL of the sensor reaches to 0.71 ppb when the integration time reaches 100 s.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"41 ","pages":"Article 100681"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11731772/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142985607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.pacs.2024.100676
Camilo Cano , Amir Gholampour , Marc van Sambeek , Richard Lopata , Min Wu
Photoacoustic imaging (PAI) is a developing image modality that benefits from light–matter interaction and low acoustic attenuation to provide functional information on tissue composition at relatively large depths. Several studies have reported the potential of dichroism-sensitive photoacoustic (DS-PA) imaging to expand PAI capabilities by obtaining morphological information of tissue regarding anisotropy and predominant orientation. However, most of these studies have limited their analysis to superficial scanning of samples, where fluence effects are negligible. Herein, we present a mathematical model for the in-depth analysis of the DS-PA signal of biological samples, focusing on estimating tissue orientation. Our model is validated with a B-scan setup for DS-PA imaging in ex-vivo porcine tendon samples, for which collagen displays optical anisotropy. Results show that for in-depth DS-PA imaging, the accumulative fluence modulation due to dichroism overcomes the effect of absorption dichroism affecting the measured signals; however, this effect can be corrected based on the presented model for determining fiber orientation.
{"title":"Dichroism-sensitive photoacoustic imaging for in-depth estimation of the optic axis in fibrous tissue","authors":"Camilo Cano , Amir Gholampour , Marc van Sambeek , Richard Lopata , Min Wu","doi":"10.1016/j.pacs.2024.100676","DOIUrl":"10.1016/j.pacs.2024.100676","url":null,"abstract":"<div><div>Photoacoustic imaging (PAI) is a developing image modality that benefits from light–matter interaction and low acoustic attenuation to provide functional information on tissue composition at relatively large depths. Several studies have reported the potential of dichroism-sensitive photoacoustic (DS-PA) imaging to expand PAI capabilities by obtaining morphological information of tissue regarding anisotropy and predominant orientation. However, most of these studies have limited their analysis to superficial scanning of samples, where fluence effects are negligible. Herein, we present a mathematical model for the in-depth analysis of the DS-PA signal of biological samples, focusing on estimating tissue orientation. Our model is validated with a B-scan setup for DS-PA imaging in ex-vivo porcine tendon samples, for which collagen displays optical anisotropy. Results show that for in-depth DS-PA imaging, the accumulative fluence modulation due to dichroism overcomes the effect of absorption dichroism affecting the measured signals; however, this effect can be corrected based on the presented model for determining fiber orientation.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"41 ","pages":"Article 100676"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11697244/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142933666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.pacs.2024.100678
Zhongyu Wang , Jing Min , Yong Sun , Xuesong Wang , Xiuguo Chen , Zirong Tang , Shiyuan Liu
Femtosecond photoacoustic detection is a powerful all-optical technique for characterizing metal nanofilms. However, the lack of accurate descriptions of the temperature-dependent optical properties of metal nanofilms during ultrafast thermal processes hinders the deep understanding of this dynamic behavior, leading to compromised measurement accuracy. To address this, we developed Critical Point Models (CPMs) for copper and AlCu nanofilms to describe their dynamic optical properties during photoacoustic testing. By integrating dynamic behavior into ultrafast laser-matter interaction and acousto-optic processes, we explored the temperature effects throughout testing. Numerical simulations were performed to analyze the temperature, stress, and surface reflectivity distributions of the nanofilms. Compared to experimental results, our dynamic models significantly improved prediction accuracy for both copper and AlCu nanofilms. This highlights the importance of temperature dependence in femtosecond photoacoustic testing and validates our model's capability to capture the behavior of metal nanofilms under ultrafast laser irradiation.
{"title":"Temperature dependence of femtosecond photoacoustic process in high-precision characterization for metal nanofilms","authors":"Zhongyu Wang , Jing Min , Yong Sun , Xuesong Wang , Xiuguo Chen , Zirong Tang , Shiyuan Liu","doi":"10.1016/j.pacs.2024.100678","DOIUrl":"10.1016/j.pacs.2024.100678","url":null,"abstract":"<div><div>Femtosecond photoacoustic detection is a powerful all-optical technique for characterizing metal nanofilms. However, the lack of accurate descriptions of the temperature-dependent optical properties of metal nanofilms during ultrafast thermal processes hinders the deep understanding of this dynamic behavior, leading to compromised measurement accuracy. To address this, we developed Critical Point Models (CPMs) for copper and AlCu nanofilms to describe their dynamic optical properties during photoacoustic testing. By integrating dynamic behavior into ultrafast laser-matter interaction and acousto-optic processes, we explored the temperature effects throughout testing. Numerical simulations were performed to analyze the temperature, stress, and surface reflectivity distributions of the nanofilms. Compared to experimental results, our dynamic models significantly improved prediction accuracy for both copper and AlCu nanofilms. This highlights the importance of temperature dependence in femtosecond photoacoustic testing and validates our model's capability to capture the behavior of metal nanofilms under ultrafast laser irradiation.</div></div>","PeriodicalId":56025,"journal":{"name":"Photoacoustics","volume":"41 ","pages":"Article 100678"},"PeriodicalIF":7.1,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11719839/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142973424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.pacs.2024.100677
Weilin Ye , Linfeng He , Weihao Liu , Zhile Yuan , Kaiyuan Zheng , Guolin Li
Traditional beat frequency quartz-enhanced photoacoustic spectroscopy (BF-QEPAS) are limited by short energy accumulation times and the necessity of a decay period, leading to weaker signals and longer measurement cycles. Herein, we present a novel optomechanical energy-enhanced (OEE-) BF-QEPAS technique for fast and sensitive gas sensing. Our approach employs periodic pulse-width modulation (PWM) of the laser signal with an optimized duty cycle, maintaining the quartz tuning fork's (QTF) output at a stable steady-state level by applying stimulus signals at each half-period and allowing free vibration in alternate half-periods to minimize energy dissipation. This method enhances optomechanical energy accumulation in the QTF, resulting in an approximate 33-fold increase in response speed and a threefold increase in signal intensity compared to conventional BF-QEPAS. We introduce an energy efficiency coefficient K to quantify the relationship between transient signal amplitude and measurement duration, exploring its dependence on the modulation signal's period and duty cycle. Theoretical analyses and numerical simulations demonstrate that the maximum K occurs at a duty cycle of 50 % and an optimized beat frequency Δf of 30 Hz. Experimental results using methane reveal a detection limit of 2.17 ppm with a rapid response time of 33 ms. The OEE-BF-QEPAS technique exhibits a wide dynamic range with exceptional linearity over five orders of magnitude and a record noise-equivalent normalized absorption (NNEA) coefficient of 9.46 × 10−10 W cm−1 Hz−1/2. Additionally, a self-calibration method is proposed for correcting resonant frequency shifts. The proposed method holds immense potential for applications requiring fast and precise gas detection.
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