Journal of Biomedical Optics最新文献

{"title":"Optical digital twins for disease prevention, diagnosis, therapy, and intervention.","authors":"Aydogan Ozcan, Melissa C Skala, Brian W Pogue, Jürgen Popp, Laura Marcu, Colleen E Clancy","doi":"10.1117/1.JBO.31.8.080601","DOIUrl":"10.1117/1.JBO.31.8.080601","url":null,"abstract":"<p><strong>Significance: </strong>Digital twins are transitioning from conceptual models to operational frameworks that link measurement, prediction, and intervention in biomedicine. However, most biomedical digital twin efforts remain fragmented, with limited integration across biological scales, sensing modalities, and clinical decision points. Biophotonics provides a uniquely suited measurement foundation for biomedical digital twins by enabling quantitative, physics-grounded, and longitudinal noninvasive measurements spanning molecular, cellular, tissue, organ, and whole-body scales. These capabilities position photonics as a foundational measurement layer for next-generation biomedical digital twins.</p><p><strong>Aim: </strong>To synthesize current advances and future opportunities in optical digital twins and to establish a unifying framework for how photonic sensing can support digital twin architectures for disease diagnosis, therapy guidance, prevention, continuous monitoring, and interventional healthcare.</p><p><strong>Approach: </strong>This white paper summarizes perspectives presented at the annual meeting of the international society for optics and photonics (SPIE Photonics West), in the session \"Digital Twins as New Approach Methodologies (NAMs) in Biophotonics.\" We review five complementary implementations of the digital twin paradigm: (i) virtual tissue staining for histopathology, which combines label-free optical imaging with machine learning-based inference to generate clinically interpretable representations with uncertainty quantification and validation; (ii) cell-level metabolic digital twins that use autofluorescence and redox imaging to predict patient-specific therapeutic responses in tumor organoids and immune cells under controlled perturbations; (iii) therapeutic digital twin frameworks for radiation therapy, in which Cherenkov imaging and radiation chemistry sensing verify treatment delivery and enable biophysical model correction and personalization; (iv) personalized optical digital twins for continuous monitoring that integrate longitudinal photonic sensing with physiological and contextual data to support early detection, prevention, and adaptive care; and (v) personalized digital twins for interventional healthcare.</p><p><strong>Results: </strong>Across these diverse applications, a common digital twin architecture emerges. Optical measurements define patient state, inference models translate measurements into predictions, therapeutic interventions perturb the system, verification measurements constrain and validate execution, and longitudinal sensing continuously updates the twin over time. The reviewed examples demonstrate that optical measurements can serve as a scalable and biologically relevant data layer linking prediction and intervention across multiple levels of biological organization.</p><p><strong>Conclusions: </strong>Optical digital twins are no longer merely a conceptual aspiration but are emer","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"080601"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13440430/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148678744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Subregion-based maximum similarity search registration method for transverse chromatic aberration correction in ultra-widefield scanning laser ophthalmoscopy images.","authors":"Lin Ji, Yunshuai Mi, Dewen Xu, Shuo Wang, ShuaiWei Mu, Yun Xiao, HaoMin Yang, Wei Huang, Yunhai Zhang, Wei Xia","doi":"10.1117/1.JBO.31.8.086001","DOIUrl":"10.1117/1.JBO.31.8.086001","url":null,"abstract":"<p><strong>Significance: </strong>Ultra-widefield scanning laser ophthalmoscopy (UWF SLO), a confocal scanning-based ophthalmic imaging modality widely used in clinical and research ophthalmology, offers an ultra-wide field of view, high resolution, and real-time dynamic imaging. However, multiwavelength imaging-induced transverse chromatic aberration (TCA) is markedly exacerbated in the peripheral retina, causing ghosting artifacts of retinal vessels and other critical anatomical structures. This severely limits image quality and the reliability of downstream quantitative analysis.</p><p><strong>Aim: </strong>We aim to correct TCA in multiwavelength UWF SLO images using a subregion-based maximum similarity search registration method, thereby eliminating vascular ghosting artifacts to enhance image quality for reliable clinical analysis.</p><p><strong>Approach: </strong>In this study, we address the nonuniform TCA between the red and green channels in multiwavelength UWF SLO imaging through three core steps: grid-based subregion sampling, high-precision control point extraction via local optimal matching guided by zero-mean normalized cross-correlation (ZNCC), and global perspective transformation model fitting. The effectiveness of the proposed method was validated on fundus image samples acquired by our in-house-developed UWF SLO system, through both qualitative visual assessment and quantitative evaluation metrics.</p><p><strong>Results: </strong>The proposed correction method significantly mitigated TCA in UWF SLO images and greatly improved the spatial alignment of retinal vascular contours between the red and green channels. Validation on 11 fundus images showed a significant enhancement in vascular matching performance: the mean dice similarity coefficient increased by 26.7% relatively (from <math><mrow><mn>0.595</mn> <mo>±</mo> <mn>0.060</mn></mrow> </math> to <math><mrow><mn>0.754</mn> <mo>±</mo> <mn>0.035</mn></mrow> </math> ) and the mean intersection over union increased by 42.5% relatively (from <math><mrow><mn>0.426</mn> <mo>±</mo> <mn>0.061</mn></mrow> </math> to <math><mrow><mn>0.607</mn> <mo>±</mo> <mn>0.044</mn></mrow> </math> ). Paired samples t-test verified highly statistically significant improvements in both metrics (all <math><mrow><mi>p</mi> <mo><</mo> <mn>0.001</mn></mrow> </math> ).</p><p><strong>Conclusions: </strong>The proposed subregion-based maximum similarity search registration method effectively corrects TCA in multiwavelength UWF SLO fundus images, significantly improves image quality, and provides reliable technical support for clinical ophthalmic practice and downstream quantitative fundus image analysis.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"086001"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13428614/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148653902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Noise-aware dynamic convolution for improved generalizability of retinal disease diagnosis using optical coherence tomography images.","authors":"Deeksha Chutani, Phaneendra K Yalavarthy","doi":"10.1117/1.JBO.31.8.086006","DOIUrl":"10.1117/1.JBO.31.8.086006","url":null,"abstract":"<p><strong>Significance: </strong>Optical coherence tomography (OCT) is widely used for the diagnosis of retinal diseases. However, deep learning models trained on a single dataset often degrade when deployed across scanners and clinical sites due to device-dependent speckle variability and acquisition differences, limiting their reliability in real-world screening.</p><p><strong>Aim: </strong>We aim to develop a lightweight deep learning framework that leverages speckle characteristics in OCT images to improve cross-scanner generalizability for retinal disease classification while preserving real-time inference efficiency.</p><p><strong>Approach: </strong>We propose NA-DyCNN, a noise-aware dynamic convolutional neural network that minimizes the expected classification risk over multiple stochastic realizations of multiplicative speckle perturbations and regularizes the dynamic routing mechanism to produce scanner-invariant kernel mixtures. The framework was evaluated using over 105,000 B-scans from three heterogeneous OCT cohorts under strict zero-shot cross-dataset transfer.</p><p><strong>Results: </strong>NA-DyCNN consistently outperformed lightweight baselines across four zero-shot cross-dataset transfer scenarios, achieving up to 92.87% accuracy, a weighted <math> <mrow><msub><mi>F</mi> <mn>2</mn></msub> </mrow> </math> score of 92.89%, and Cohen's <math><mrow><mi>κ</mi></mrow> </math> of up to 0.896, demonstrating improved robustness and generalization under cross-dataset shifts. The model maintained high efficiency with only 0.4 M parameters and an inference latency of 0.53 ms per B-scan on an NVIDIA GB10 GPU.</p><p><strong>Conclusions: </strong>Modeling postacquisition speckle variability during training improves the generalizability of OCT classifiers without increasing the inference cost, thereby enabling the more reliable deployment of artificial intelligence (AI)-assisted retinal screening across heterogeneous imaging systems.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"086006"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13464582/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148720413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time-resolved laser speckle contrast imaging (TR-LSCI) of cerebral blood flow response to intracranial pressure elevation.","authors":"Faraneh Fathi, Peiwen Zhang, Mehrana Mohtasebi, Paul Mos, Claudio Bruschini, Edoardo Charbon, Jin Chen, Li Chen, Guoqiang Yu, Lei Chen","doi":"10.1117/1.JBO.31.8.086007","DOIUrl":"10.1117/1.JBO.31.8.086007","url":null,"abstract":"<p><strong>Significance: </strong>Cerebral autoregulation (CA) reflects the dynamic coupling among cerebral blood flow (CBF), intracranial pressure (ICP), and arterial blood pressure (ABP); its failure contributes to secondary brain injury. Existing bedside methods rely on indirect or spatially limited CBF surrogates and cannot resolve microvascular flow dynamics across space, depth, and time.</p><p><strong>Aim: </strong>To develop, optimize, and apply a scalable, noncontact time-resolved laser speckle contrast imaging (TR-LSCI) platform for depth-sensitive, high-speed, wide-field CBF imaging during controlled ICP perturbations.</p><p><strong>Approach: </strong>TR-LSCI synchronized a 20-MHz pulsed laser with a time-gated, single-photon avalanche diode (SPAD) camera ( <math><mrow><mn>512</mn> <mo>×</mo> <mn>512</mn> <mtext>  pixels</mtext></mrow> </math> ) to detect diffuse photons at varying path lengths, enabling depth-resolved microvascular CBF imaging. Noise-corrected diffuse speckle analysis was implemented to reduce bias at gates with low signal-to-noise ratio and depth sensitivity was assessed across multiple time gates. Benchtop and mobile TR-LSCI systems were applied in adult rats and a neonatal piglet with synchronized invasive ICP and ABP measurements.</p><p><strong>Results: </strong>TR-LSCI captured spatially heterogeneous, pulsatile CBF dynamics at up to 52 Hz over large cortical fields of view, with heart rate estimates statistically equivalent to those from ICP and ABP. Consistent CBF trends across gates support robust physiological interpretation despite depth-dependent differences in absolute magnitude. Multivariable analysis identified reproducible, phase-dependent CA transitions encompassing preserved autoregulation, ABP-driven compensation, and ICP-constrained CBF suppression; notably, CBF alone exhibited distinct phase signatures.</p><p><strong>Conclusion: </strong>TR-LSCI enables dynamic, physiology-informed neurovascular monitoring and supports future bedside CA assessment.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"086007"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13524067/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148850437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pigmentation-dependent skin injury thresholds with nanosecond single-pulse laser exposure.","authors":"Junior Arroyo, Jiaxin Zhang, Madhavi Tripathi, Junhao Zhang, Nethra Venkatayogi, Jamie Enslein, Muyinatu A Lediju Bell","doi":"10.1117/1.JBO.31.8.085001","DOIUrl":"10.1117/1.JBO.31.8.085001","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Significance: &lt;/strong&gt;Maximum permissible exposure limits defined in ANSI Z136.1 are broadly protective, but they do not explicitly account for pigmentation differences in skin. As a result, the lack of experimental data quantifying the effect of pigmentation on injury thresholds constrains accurate interpretation when melanin is a primary optical absorber, which has direct implications for the performance of optics-based imaging methods.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Aim: &lt;/strong&gt;We experimentally determined the pigmentation-dependent laser exposure dose that produces a visible injury in 50% of exposed sites (i.e., &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;ED&lt;/mi&gt; &lt;mn&gt;50&lt;/mn&gt;&lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; injury thresholds) with nanosecond, 750-nm-wavelength pulses, and we provide the first known quantification of relationships between melanin index (MI) and individual typology angle (ITA) or erythema index (EI) through colorimetric measurements.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Approach: &lt;/strong&gt;Fifty total abdominal skin sites per swine were identified on three swine with different pigmentation phenotypes (median ITA values per swine ranged &lt;math&gt;&lt;mrow&gt;&lt;mo&gt;-&lt;/mo&gt; &lt;mn&gt;18&lt;/mn&gt; &lt;mo&gt;°&lt;/mo&gt;&lt;/mrow&gt; &lt;/math&gt; to 87°). Single-laser pulses with 5-ns pulse duration, 750-nm-wavelength, and energies of 35, 40, 50, 60, and 65 mJ per pulse were delivered to 10 sites per energy level per swine. Laser-exposed sites were visually assessed at early post-exposure intervals, followed by colorimeter measurements of MI, ITA, and EI. Probit regression analysis was used to compute the &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;ED&lt;/mi&gt; &lt;mn&gt;50&lt;/mn&gt;&lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; thresholds, followed by a polynomial regression analysis conducted to relate ITA to MI and EI to MI.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Dark-skinned swine ( &lt;math&gt; &lt;mrow&gt;&lt;mrow&gt;&lt;mtext&gt;median&lt;/mtext&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mtext&gt; &lt;/mtext&gt;&lt;/mrow&gt; &lt;mi&gt;ITA&lt;/mi&gt; &lt;mo&gt;=&lt;/mo&gt; &lt;mo&gt;-&lt;/mo&gt; &lt;mn&gt;18&lt;/mn&gt; &lt;mo&gt;°&lt;/mo&gt;&lt;/mrow&gt; &lt;/math&gt; ) exhibited a 27.7% lower &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;ED&lt;/mi&gt; &lt;mn&gt;50&lt;/mn&gt;&lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; ( &lt;math&gt;&lt;mrow&gt;&lt;mn&gt;323.94&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;mi&gt;mJ&lt;/mi&gt; &lt;mo&gt;/&lt;/mo&gt; &lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;cm&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt; &lt;/msup&gt; &lt;/mrow&gt; &lt;/math&gt; ) than light-skinned swine ( &lt;math&gt; &lt;mrow&gt;&lt;mrow&gt;&lt;mtext&gt;median&lt;/mtext&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mtext&gt; &lt;/mtext&gt;&lt;/mrow&gt; &lt;mi&gt;ITA&lt;/mi&gt; &lt;mo&gt;=&lt;/mo&gt; &lt;mn&gt;69.5&lt;/mn&gt; &lt;mo&gt;°&lt;/mo&gt;&lt;/mrow&gt; &lt;/math&gt; , &lt;math&gt; &lt;mrow&gt; &lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;ED&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mn&gt;50&lt;/mn&gt;&lt;/mrow&gt; &lt;/msub&gt; &lt;mo&gt;=&lt;/mo&gt; &lt;mn&gt;448.36&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;mi&gt;mJ&lt;/mi&gt; &lt;mo&gt;/&lt;/mo&gt; &lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;cm&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt; &lt;/msup&gt; &lt;/mrow&gt; &lt;/math&gt; ), which is consistent with increased melanin-mediated absorption in the darker-skinned swine. The lightest-skin swine ( &lt;math&gt; &lt;mrow&gt;&lt;mrow&gt;&lt;mtext&gt;median&lt;/mtext&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mtext&gt; &lt;/mtext&gt;&lt;/mrow&gt; &lt;mi&gt;ITA&lt;/mi&gt; &lt;mo&gt;=&lt;/mo&gt; &lt;mn&gt;87&lt;/mn&gt; &lt;mo&gt;°&lt;/mo&gt;&lt;/mrow&gt; &lt;/math&gt; ) did not develop visible erythema within the tested exposure range, preventing &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;ED&lt;/mi&gt; &lt;mn&gt;50&lt;/mn&gt;&lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; estimation. Mathematical MI-ITA and MI-E","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"085001"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13452404/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148697703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Scattering properties of Intralipid modeled using dependent scattering theory.","authors":"Xavier Attendu, Martin Poinsinet de Sivry-Houle, Mona Shahsavari, Dirk J Faber, Edwin van der Pol, Ton G van Leeuwen","doi":"10.1117/1.JBO.31.8.085003","DOIUrl":"10.1117/1.JBO.31.8.085003","url":null,"abstract":"<p><strong>Significance: </strong>Intralipid^® is widely used as a liquid optical phantom in biomedical optics, but its scattering properties remain incompletely defined, particularly at high volume fractions where dependent scattering becomes important. A physics-based description of its scattering behavior is needed to support quantitative Monte Carlo simulations, phantom design, and calibration of biophotonic measurement systems.</p><p><strong>Aim: </strong>We aim to establish a physically grounded model of Intralipid scattering, including the scattering coefficient, reduced scattering coefficient, anisotropy, and phase function. The model covers wavelengths 400 to 1700 nm and particle volume fractions of 0.00227 to 0.227, corresponding to dilutions from 1% v/v of stock Intralipid 20% through undiluted stock Intralipid 20%. It is derived from intrinsic material properties, namely, the particle size distribution and the refractive indices of the lipid particles and aqueous medium.</p><p><strong>Approach: </strong>We combine full Mie theory for the single-particle scattering response with the multicomponent Percus-Yevick hard-sphere approximation to account for dependent scattering. The model uses recent measurements of the particle size distribution and the refractive-index dispersion of the lipid and aqueous phases. Particular attention is given to the long tail of the particle size distribution, which extends beyond the cutoff of earlier electron-microscopy-based datasets.</p><p><strong>Results: </strong>Despite its small number fraction, the long tail of the particle size distribution contributes substantially to the scattering coefficient, anisotropy, and phase function, especially at near-infrared wavelengths. The resulting predictions for the scattering coefficient, anisotropy, and reduced scattering coefficient are broadly consistent with established semi-empirical relations for Intralipid in the dependent-scattering regime, although residual wavelength- and concentration-dependent discrepancies remain. The model also provides phase functions across the full studied wavelength and concentration range, for which direct experimental reference data are currently unavailable.</p><p><strong>Conclusion: </strong>The proposed model links the optical scattering properties of Intralipid to measured material properties while incorporating dependent-scattering effects. Its broad agreement with literature-reported data on IL optical properties supports its use as a physics-based estimate, while the remaining discrepancies highlight the influence of sample variability and the limits of the underlying assumptions. The reported equations and interpolation scripts provide a practical resource for studies requiring internally consistent scattering properties across wavelength and concentration.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"085003"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13521324/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148840291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-dimensional ocular surface displacement and strain measurement using fringe projection profilometry and digital image correlation.","authors":"Victoria MacDans, Badrinath Balasubramaniam, Beiwen Li","doi":"10.1117/1.JBO.31.8.086008","DOIUrl":"10.1117/1.JBO.31.8.086008","url":null,"abstract":"<p><strong>Significance: </strong>Accurate measurement of ocular surface deformation under intraocular pressure (IOP) is essential for understanding eye biomechanics and the progression of pressure-related diseases such as glaucoma. However, existing imaging techniques often involve trade-offs among spatial resolution, system complexity, and the ability to capture full-field three-dimensional (3D) deformation on highly curved, compliant tissues.</p><p><strong>Aim: </strong>We investigate the feasibility of a noncontact measurement framework that combines fringe projection profilometry (FPP) and two-dimensional digital image correlation (2D DIC) to recover full-field 3D displacement and strain on the ocular surface during pressurization.</p><p><strong>Approach: </strong>An <i>ex vivo</i> porcine eye was subjected to controlled hydrostatic pressurization to simulate IOP variation. FPP was used to reconstruct dense 3D surface geometry across successive loading states, whereas 2D DIC was applied to corresponding texture images to estimate in-plane displacements. These measurements were fused through pixel-wise mapping to recover full-field 3D displacement vectors, from which Green-Lagrange strain components were computed and expressed in a spherical coordinate framework.</p><p><strong>Results: </strong>The proposed framework was able to capture the evolving deformation of the ocular surface, revealing spatially heterogeneous displacement and strain patterns. Localized regions of elevated strain were consistently observed, whereas the deformation fields exhibited smooth temporal progression across loading stages. The recovered strain distributions aligned with expected biomechanical behavior of the ocular structure, suggesting the capability of the method to resolve meaningful deformation features on a curved, compliant surface.</p><p><strong>Conclusions: </strong>The combined FPP-DIC framework indicates potential as a viable approach for measuring dense 3D displacement and strain on the ocular surface. This feasibility study establishes the potential of structured-light-based methods for ocular biomechanics and lays the foundation for future quantitative validation and <i>in vivo</i> applications.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"086008"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13496234/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148793038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Breaking the 100-nm resolution barrier with multiphoton microscopy using image scanning microscopy and optical fluctuation imaging.","authors":"Anton Classen, Alma Fernández, Ajithamithra Dharmasiri, Cristobal Rodriguez, Rahul Srinivasan, Aleksei M Zheltikov, Girish S Agarwal, Aart J Verhoef","doi":"10.1117/1.JBO.31.8.086501","DOIUrl":"10.1117/1.JBO.31.8.086501","url":null,"abstract":"<p><strong>Significance: </strong>Multiphoton fluorescence microscopy is the technique of choice for investigations of thick, highly scattering samples, but is outperformed by single-photon super-resolution techniques in spatial resolving power.</p><p><strong>Aim: </strong>We combine two-photon microscopy with two super-resolution microscopy methods, namely, image scanning microscopy and super-resolution optical fluctuation imaging to overcome the reduction in resolution of laser scanning multiphoton microscopy compared with confocal microscopy. Making use of higher-order cumulants and image deconvolution a resolution better than 100 nm can be achieved.</p><p><strong>Approach: </strong>Two-photon image scanning optical fluctuation imaging is achieved by detecting the descanned signal of fluorescence on a 23-element single photon avalanche detector and analyzing (higher order) cumulants of the temporal evolution of the signals. We test the performance of our method with samples of dispersed quantum dots. We show the applicability of two-photon image scanning optical fluctuation imaging to biological samples with fixed mouse ventral midbrain neurons with quantum dot labeled tubulin.</p><p><strong>Results: </strong>Combining two photon laser scanning microscopy with image scanning microscopy allows to overcome the reduction in resolution caused by the longer wavelength excitation inherent to multiphoton excitation. Analyzing the temporal fluctuations of the signals by calculating cumulants allows to surpass the resolution achieved with conventional confocal imaging of the same fluorophores, and the use of higher-order cumulants and deconvolution allows to achieve a lateral resolution of 75 nm when imaging quantum dots emitting at 625 nm.</p><p><strong>Conclusions: </strong>Combining two-photon microscopy with image scanning microscopy and optical fluctuation imaging allows to achieve a 5-fold improvement in resolution over standard two-photon microscopy, and a 3.5-fold improvement over conventional widefield imaging of the same fluorophores. This represents the first time, to our knowledge, that sub-100 nm imaging is achieved using multiphoton laser scanning microscopy.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"086501"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13430961/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148669711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative evaluation of skin pigmentation effects on photoplethysmography using vascular finger phantoms and Monte Carlo simulation.","authors":"Laura Osorio-Sanchez, James M May, Panicos A Kyriacou","doi":"10.1117/1.JBO.31.8.087001","DOIUrl":"10.1117/1.JBO.31.8.087001","url":null,"abstract":"<p><strong>Significance: </strong>Photoplethysmography (PPG) underpins a wide range of clinical and consumer optical monitoring technologies. However, differences in skin pigmentation can alter light-tissue interactions through increased absorption by melanin, affecting PPG signal quality and potentially contributing to performance disparities across populations.</p><p><strong>Aim: </strong>This study aimed to investigate the effect of skin pigmentation on PPG signal quality by combining an advanced vascular finger phantom with Monte Carlo simulations to directly link experimentally measured PPG features to underlying photon transport behavior in both reflectance and transmittance measurement modes.</p><p><strong>Approach: </strong>A multilayer vascular finger phantom incorporating a three-level, physiologically inspired vascular network and interchangeable skin layers representing pale, medium, and dark skin pigmentation was developed. The optical properties were characterized across 530, 665, and 940 nm. PPG signals were acquired in reflectance and transmittance modes under controlled pulsatile flow conditions. Quantitative signal metrics, including peak-to-peak amplitude, signal-to-noise ratio (SNR), and AC/DC ratio, were extracted. Monte Carlo simulations were implemented using the measured optical properties to model photon transport, energy deposition, and depth-dependent absorption.</p><p><strong>Results: </strong>Increasing skin pigmentation resulted in systematic reduction in all PPG features across all wavelengths, with the strongest attenuation observed at shorter wavelengths. Monte Carlo simulations revealed increased superficial absorption and reduced photon penetration in darker skin layers, closely matching experimental trends.</p><p><strong>Conclusions: </strong>This combined experimental-computational framework provides quantitative and mechanistic insight into how skin pigmentation influences light-tissue interaction and PPG signal quality, with direct relevance to emerging wearables and PPG-based applications, where signal quality disparities across skin tones may impact algorithm performance.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"087001"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13498974/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148793668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep learning for optoacoustic imaging of reversibly switchable proteins: training and performance testing using simulated multispectral optoacoustic tomography images.","authors":"William Vale, Jeffrey Bamber, Hasan Koruk, Gustavo Carneiro, Lucia Florescu","doi":"10.1117/1.JBO.31.8.086002","DOIUrl":"10.1117/1.JBO.31.8.086002","url":null,"abstract":"<p><strong>Significance: </strong>Reversibly switchable optoacoustic proteins (rsOAPs) are a promising candidate for sensitive and quantitative optoacoustic (OA) imaging of genetically modified cell populations, such as chimeric antigen receptor (CAR) T-cells used in cancer immunotherapy. Although detection of rsOAPs has been demonstrated using classical machine learning approaches, there is still a need for higher detection sensitivity and more accurate quantification.</p><p><strong>Aim: </strong>We aim to develop deep learning approaches for improving the sensitivity of the detection and accuracy of quantification of rsOAPs with OA imaging and a 3D simulation framework to create synthetic datasets for machine learning experiments.</p><p><strong>Approach: </strong>We developed a forward model to generate labeled synthetic OA images of rsOAPs that takes into account light transport, acoustic wave propagation, and light-driven transitions between two different forms of the proteins. We used the synthetic images to train and evaluate machine learning models, including two convolutional neural networks and a transformer neural network, on the binary semantic segmentation and pixel-level prediction (regression) of the spatial distribution of the rsOAPs.</p><p><strong>Results: </strong>With this dataset, fine-tuned convolutional and transformer neural networks substantially outperformed classical machine learning approaches in the binary semantic segmentation of rsOAPs within the inhomogeneities (regions representing tumors), increasing the sensitivity from around 0.38 to 0.55 for noiseless data and from around 0.15 to 0.53 under a high level of stochastic noise ( <math> <mrow> <msub><mrow><mi>SNR</mi></mrow> <mrow><mi>dB</mi></mrow> </msub> <mo>=</mo> <mn>8.8</mn></mrow> </math> ) while maintaining a specificity of around 0.84, down to protein concentrations of order <math> <mrow> <msup><mrow><mn>10</mn></mrow> <mrow><mo>-</mo> <mn>8</mn></mrow> </msup> <mtext>  </mtext> <mi>M</mi></mrow> </math> .</p><p><strong>Conclusions: </strong>A new methodology for the generation of synthetic OA imaging data of rsOAPs is presented, and the feasibility of deep learning for the accurate semantic segmentation and quantification of rsOAPs in OA imaging is demonstrated.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"086002"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13454766/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148706394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}