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1.
Biomed Opt Express ; 15(9): 5009-5024, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39296388

RESUMO

Biosynthesis in bioreactors plays a vital role in many applications, but tools for accurate in situ monitoring of the cells are still lacking. By engineering the cells such that their conditions are reported through fluorescence, it is possible to fill in the gap using fluorescence diffuse optical tomography (fDOT). However, the spatial accuracy of the reconstruction can still be limited, due to e.g. undersampling and inaccurate estimation of the optical properties. Utilizing controlled phantom studies, we use a two-step hybrid approach, where a preliminary fDOT result is first obtained using the classic model-based optimization, and then enhanced using a neural network. We show in this paper using both simulated and phantom experiments that the proposed method can lead to a 8-fold improvement (Intersection over Union) of fluorescence inclusion reconstruction in noisy conditions, at the same speed of conventional neural network-based methods. This is an important step towards our ultimate goal of fDOT monitoring of bioreactors.

2.
Biomed Opt Express ; 15(8): 4859-4876, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39347003

RESUMO

Diffuse optical tomography (DOT) enhances the localization accuracy of neural activity measured with electroencephalography (EEG) while preserving EEG's high temporal resolution. However, the spatial resolution of reconstructed activity diminishes for deeper neural sources. In this study, we analyzed DOT-enhanced EEG localization of neural sources modeled at depths ranging from 11-25 mm in simulations. Our findings reveal systematic biases in reconstructed depth related to DOT channel length. To address this, we developed a data-informed method for selecting DOT channels to improve the spatial accuracy of DOT-enhanced EEG reconstruction. Using our method, the average absolute reconstruction depth errors of DOT reconstruction across all depths are 0.9 ± 0.6 mm, 1.2 ± 0.9 mm, and 1.2 ± 1.1 mm under noiseless, low-level noise, and high-level noise conditions, respectively. In comparison, using fixed channel lengths resulted in errors of 2.6 ± 1.5 mm, 5.0 ± 2.6 mm, and 7.3 ± 4.5 mm under the same conditions. Consequently, our method improved the depth accuracy of DOT reconstructions and facilitated the use of more accurate spatial priors for EEG reconstructions, enhancing the overall precision of the technique.

3.
Biomed Opt Express ; 15(8): 4525-4539, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39347008

RESUMO

Recent development of radiotherapy (RT) has heightened the use of radiation in managing pancreatic cancer. Thus, there is a need to investigate pancreatic cancer in a pre-clinical setting to advance our understanding of the role of RT. Widely-used cone-beam CT (CBCT) imaging cannot provide sufficient soft tissue contrast to guide irradiation. The pancreas is also prone to motion. Large collimation is unavoidably used for irradiation, costing normal tissue toxicity. We innovated a bioluminescence tomography (BLT)-guided system to address these needs. We established an orthotopic pancreatic ductal adenocarcinoma (PDAC) mouse model to access BLT. Mice underwent multi-projection and multi-spectral bioluminescence imaging (BLI), followed by CBCT imaging in an animal irradiator for BLT reconstruction and radiation planning. With optimized absorption coefficients, BLT localized PDAC at 1.25 ± 0.19 mm accuracy. To account for BLT localization uncertainties, we expanded the BLT-reconstructed volume with margin to form planning target volume(PTVBLT) for radiation planning, covering 98.7 ± 2.2% of PDAC. The BLT-guided conformal plan can cover 100% of tumors with limited normal tissue involvement across both inter-animal and inter-fraction cases, superior to the 2D BLI-guided conventional plan. BLT offers unique opportunities to localize PDAC for conformal irradiation, minimize normal tissue involvement, and support reproducibility in RT studies.

4.
J Biomed Opt ; 29(7): 076004, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39035576

RESUMO

Significance: Frequency-domain diffuse optical tomography (FD-DOT) could enhance clinical breast tumor characterization. However, conventional diffuse optical tomography (DOT) image reconstruction algorithms require case-by-case expert tuning and are too computationally intensive to provide feedback during a scan. Deep learning (DL) algorithms front-load computational and tuning costs, enabling high-speed, high-fidelity FD-DOT. Aim: We aim to demonstrate a simultaneous reconstruction of three-dimensional absorption and reduced scattering coefficients using DL-FD-DOT, with a view toward real-time imaging with a handheld probe. Approach: A DL model was trained to solve the DOT inverse problem using a realistically simulated FD-DOT dataset emulating a handheld probe for human breast imaging and tested using both synthetic and experimental data. Results: Over a test set of 300 simulated tissue phantoms for absorption and scattering reconstructions, the DL-DOT model reduced the root mean square error by 12 % ± 40 % and 23 % ± 40 % , increased the spatial similarity by 17 % ± 17 % and 9 % ± 15 % , increased the anomaly contrast accuracy by 9 % ± 9 % ( µ a ), and reduced the crosstalk by 5 % ± 18 % and 7 % ± 11 % , respectively, compared with model-based tomography. The average reconstruction time was reduced from 3.8 min to 0.02 s for a single reconstruction. The model was successfully verified using two tumor-emulating optical phantoms. Conclusions: There is clinical potential for real-time functional imaging of human breast tissue using DL and FD-DOT.


Assuntos
Algoritmos , Neoplasias da Mama , Aprendizado Profundo , Processamento de Imagem Assistida por Computador , Imagens de Fantasmas , Tomografia Óptica , Tomografia Óptica/métodos , Tomografia Óptica/instrumentação , Humanos , Processamento de Imagem Assistida por Computador/métodos , Neoplasias da Mama/diagnóstico por imagem , Mama/diagnóstico por imagem , Feminino , Imageamento Tridimensional/métodos
5.
J Adolesc Health ; 75(1): 133-139, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38597839

RESUMO

PURPOSE: In the current world, adolescents are less likely to turn to physical activity games and often prefer to spend more time in the technological and digital world and have fun with digital games. This study aimed to explore reasons for preferring digital games to physical activity games in adolescents. METHODS: Twenty-one adolescents participated in this qualitative study. The participants' age ranged from 11 to 19 who participated in semistructured interviews. The recorded interviews underwent thematic analysis to identify overall themes. RESULTS: Five overall themes were identified from the interviews regarding reasons for preferring digital games over physical activity games. Identified themes included game characteristics, game space, game outcomes, peer pressure, and accessibility. DISCUSSION: The findings of this research contribute to design adolescent-centered interventions that sustain/increase adolescents' interest in physical activity games and protect them from excessive/harmful use of digital games.


Assuntos
Comportamento do Adolescente , Exercício Físico , Pesquisa Qualitativa , Jogos de Vídeo , Humanos , Adolescente , Feminino , Masculino , Exercício Físico/psicologia , Comportamento do Adolescente/psicologia , Criança , Adulto Jovem , Entrevistas como Assunto
6.
Phys Med Biol ; 69(2)2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38181420

RESUMO

Objective. Small-field dosimetry is an ongoing challenge in radiotherapy quality assurance (QA) especially for radiosurgery systems such as CyberKnifeTM. The objective of this work is to demonstrate the use of a plastic scintillator imaged with a commercial camera to measure the output factor of a CyberKnife system. The output factor describes the dose on the central axis as a function of collimator size, and is a fundamental part of CyberKnife QA and integral to the data used in the treatment planning system.Approach. A self-contained device consisting of a solid plastic scintillator and a camera was build in a portable Pelicase. Photographs were analysed using classical methods and with convolutional neural networks (CNN) to predict beam parameters which were then compared to measurements.Main results. Initial results using classical image processing to determine standard QA parameters such as percentage depth dose (PDD) were unsuccessful, with 34% of points failing to meet the Gamma criterion (which measures the distance between corresponding points and the relative difference in dose) of 2 mm/2%. However, when images were processed using a CNN trained on simulated data and a green scintillator sheet, 92% of PDD curves agreed with measurements with a microdiamond detector to within 2 mm/2% and 78% to 1%/1 mm. The mean difference between the output factors measured using this system and a microdiamond detector was 1.1%. Confidence in the results was enhanced by using the algorithm to predict the known collimator sizes from the photographs which it was able to do with an accuracy of less than 1 mm.Significance. With refinement, a full output factor curve could be measured in less than an hour, offering a new approach for rapid, convenient small-field dosimetry.


Assuntos
Aprendizado Profundo , Radiocirurgia , Radiometria/métodos , Radiocirurgia/métodos , Algoritmos , Redes Neurais de Computação
7.
Physiol Meas ; 44(12)2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38061053

RESUMO

Objective.In this paper, we present a detailedin vivocharacterization of the optical and hemodynamic properties of the human sternocleidomastoid muscle (SCM), obtained through ultrasound-guided near-infrared time-domain and diffuse correlation spectroscopies.Approach.A total of sixty-five subjects (forty-nine females, sixteen males) among healthy volunteers and thyroid nodule patients have been recruited for the study. Their SCM hemodynamic (oxy-, deoxy- and total hemoglobin concentrations, blood flow, blood oxygen saturation and metabolic rate of oxygen extraction) and optical properties (wavelength dependent absorption and reduced scattering coefficients) have been measured by the use of a novel hybrid device combining in a single unit time-domain near-infrared spectroscopy, diffuse correlation spectroscopy and simultaneous ultrasound imaging.Main results.We provide detailed tables of the results related to SCM baseline (i.e. muscle at rest) properties, and reveal significant differences on the measured parameters due to variables such as side of the neck, sex, age, body mass index, depth and thickness of the muscle, allowing future clinical studies to take into account such dependencies.Significance.The non-invasive monitoring of the hemodynamics and metabolism of the sternocleidomastoid muscle during respiration became a topic of increased interest partially due to the increased use of mechanical ventilation during the COVID-19 pandemic. Near-infrared diffuse optical spectroscopies were proposed as potential practical monitors of increased recruitment of SCM during respiratory distress. They can provide clinically relevant information on the degree of the patient's respiratory effort that is needed to maintain an optimal minute ventilation, with potential clinical application ranging from evaluating chronic pulmonary diseases to more acute settings, such as acute respiratory failure, or to determine the readiness to wean from invasive mechanical ventilation.


Assuntos
Músculo Esquelético , Espectroscopia de Luz Próxima ao Infravermelho , Masculino , Feminino , Humanos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Músculo Esquelético/fisiologia , Pandemias , Oxigênio/metabolismo , Hemodinâmica , Ultrassonografia , Ultrassonografia de Intervenção
8.
AoB Plants ; 15(6): plad037, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38090390

RESUMO

The tomato (Solanum lycopersicum L.) is an annual vegetable cultivated all over the world. It faces biotic and abiotic stresses, such as salinity, in arid and semiarid regions. Investigating the relationship between physiological and economic traits, such as fruit yield, under stress conditions is necessary to identify tolerant genotypes. This study was conducted to identify tolerant tomato families according to the relationship between several important physiological, morphological and phenological traits. Twenty S3 families were cultivated in a factorial experiment (factor1: families and factor2: normal conditions and salinity stress) based on a randomized complete block design with three replications in 2019. Twenty physiological, agronomic and fruit-quality-related traits were investigated. Analysis of variance was used to prove the existing effective genetic diversity. Genetic diversity and the relationships between traits were graphically shown using heatmap clustering. Finally, genetic parameters, such as Pearson's correlation, trait stability index and heritability were used to calculate the mathematical value of families using the Modified Analytical Hierarchy Process. Families exhibited different behaviours under normal and stress conditions. The tolerant families responded physiologically to the salt stress. Therefore, they reduced both cell membrane degradation and photosynthesis disruption by increasing proline, lycopene, carotenoid and sugar content. Therefore, fewer reductions in morphological traits were observed in these families. The most important traits based on the selection strategy were lycopene content, K+/Na+ ratio, days to flowering and biological yield. In addition, three families, H4/T/30/1, H1/T/12/5 and H1/T/47/4, were selected as the most suitable alternatives to construct the breeding population of the next generation.

9.
Med Phys ; 50(10): 6433-6453, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37633836

RESUMO

BACKGROUND: Widely used Cone-beam computed tomography (CBCT)-guided irradiators have limitations in localizing soft tissue targets growing in a low-contrast environment. This hinders small animal irradiators achieving precise focal irradiation. PURPOSE: To advance image-guidance for soft tissue targeting, we developed a commercial-grade bioluminescence tomography-guided system (BLT, MuriGlo) for pre-clinical radiation research. We characterized the system performance and demonstrated its capability in target localization. We expect this study can provide a comprehensive guideline for the community in utilizing the BLT system for radiation studies. METHODS: MuriGlo consists of four mirrors, filters, lens, and charge-coupled device (CCD) camera, enabling a compact imaging platform and multi-projection and multi-spectral BLT. A newly developed mouse bed allows animals imaged in MuriGlo and transferred to a small animal radiation research platform (SARRP) for CBCT imaging and BLT-guided irradiation. Methods and tools were developed to evaluate the CCD response linearity, minimal detectable signal, focusing, spatial resolution, distortion, and uniformity. A transparent polycarbonate plate covering the middle of the mouse bed was used to support and image animals from underneath the bed. We investigated its effect on 2D Bioluminescence images and 3D BLT reconstruction accuracy, and studied its dosimetric impact along with the rest of mouse bed. A method based on pinhole camera model was developed to map multi-projection bioluminescence images to the object surface generated from CBCT image. The mapped bioluminescence images were used as the input data for the optical reconstruction. To account for free space light propagation from object surface to optical detector, a spectral derivative (SD) method was implemented for BLT reconstruction. We assessed the use of the SD data (ratio imaging of adjacent wavelength) in mitigating out of focusing and non-uniformity seen in the images. A mouse phantom was used to validate the data mapping. The phantom and an in vivo glioblastoma model were utilized to demonstrate the accuracy of the BLT target localization. RESULTS: The CCD response shows good linearity with < 0.6% residual from a linear fit. The minimal detectable level is 972 counts for 10 × 10 binning. The focal plane position is within the range of 13-18 mm above the mouse bed. The spatial resolution of 2D optical imaging is < 0.3 mm at Rayleigh criterion. Within the region of interest, the image uniformity is within 5% variation, and image shift due to distortion is within 0.3 mm. The transparent plate caused < 6% light attenuation. The use of the SD imaging data can effectively mitigate out of focusing, image non-uniformity, and the plate attenuation, to support accurate multi-spectral BLT reconstruction. There is < 0.5% attenuation on dose delivery caused by the bed. The accuracy of data mapping from the 2D bioluminescence images to CBCT image is within 0.7 mm. Our phantom test shows the BLT system can localize a bioluminescent target within 1 mm with an optimal threshold and only 0.2 mm deviation was observed for the case with and without a transparent plate. The same localization accuracy can be maintained for the in vivo GBM model. CONCLUSIONS: This work is the first systematic study in characterizing the commercial BLT-guided system. The information and methods developed will be useful for the community to utilize the imaging system for image-guided radiation research.

10.
IEEE Open J Eng Med Biol ; 4: 85-95, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37228451

RESUMO

An intuitive and generalisable approach to spatial-temporal feature extraction for high-density (HD) functional Near-Infrared Spectroscopy (fNIRS) brain-computer interface (BCI) is proposed, demonstrated here using Frequency-Domain (FD) fNIRS for motor-task classification. Enabled by the HD probe design, layered topographical maps of Oxy/deOxy Haemoglobin changes are used to train a 3D convolutional neural network (CNN), enabling simultaneous extraction of spatial and temporal features. The proposed spatial-temporal CNN is shown to effectively exploit the spatial relationships in HD fNIRS measurements to improve the classification of the functional haemodynamic response, achieving an average F1 score of 0.69 across seven subjects in a mixed subjects training scheme, and improving subject-independent classification as compared to a standard temporal CNN.

11.
Plant Methods ; 19(1): 25, 2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-36915142

RESUMO

BACKGROUND: Selection is one of the essential skills whereby breeders reduce the population size and increase the chance of success. Various selection methods with special applications have been developed. Superior genotypes are assessed according to interesting traits, including univariate, multivariate, phenotypic, genotypic, etc. METHODS: Mathematical calculation of the traits' importance based on the genetic makeup of investigated population (average degree of dominance/additive involved in the action of genes) and arbitrary genetic parameters is functional. In this paper, a general model for multivariate selection has been presented whereby the selection can be made for (a) more than one interesting trait, (b) the trait(s) with complex inheritance, (c) finding superior genotypes from among a large-scale population, (d) finding superior genotypes in segregating generations and (f) finding tolerant genotypes to stresses. This model is developed based on biometric concepts in four steps. MATLAB script is provided for the model, and users can easily apply that to identify the most suitable genotypes after data collection according to the breeding purposes. RESULTS: The main features of this model are simplicity, precision, repeatability, and speed (improving several traits simultaneously). All the steps and the analysis of the results are explained step by step in a case study.

12.
Microb Pathog ; 179: 106080, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36948364

RESUMO

BACKGROUND & AIMS: Hemodialysis (HD) is a life-saving procedure that purifies the blood in patients with end-stage renal disease (ESRD). Among all major complications, blood-borne diseases like hepatitis B virus (HBV) may be exposed as serious side effects of hemodialysis. A comprehensive review of the global burden of HBV among HD patients has not been written so far. The aim of the current systematic review and meta-analysis was to determine the globally epidemiology of HBV infection among HD patients. METHODS: Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, articles that investigated the prevalence of HBV among HD patients were searched from the major databases such as EMBASE, PubMed, Web of Science collection, and Scopus. Pooled prevalence with 95% CI and identification of heterogeneity were obtained using the random effects model and Cochran's Q-test, respectively, and quantification was evaluated using the I2 statistics. All statistical analyses were performed by STATA 14.1 statistical software. RESULTS: among 322 datasets (795,623 cases) that included in this study, the pooled prevalence of HBV infection among HD patients was 7.32% (95% CI: 6.53-8.15%; I2 = 97.91%), including 7.57% (95% CI: 6.69-8.48%) for HBsAg and 6.09% (95% CI: 4.05-8.49%) for DNA, respectively. In addition, based on geographic area, the prevalence was 7.44% (95% CI: 6.35-8.61%) in Asia, 4.32% (95% CI: 2.21-7.04%) in North America, 7.07% (95% CI: 6.35-8.61%) in Europe, 5.52% (95% CI: 3.60-7.78%) in Africa, 8.45% (95% CI: 5.81-11.78%) in Oceania, and 9.73% (95% CI: 7.11-12.70%) in South America. CONCLUSIONS: Our analysis indicates a relatively high prevalence of HBV infection in HD patients, even in some developed countries. Considering that ESRD patients are not able to properly respond to the vaccination strategies in order to develop an acceptable immunity, vaccination of healthy individuals is highly recommended to arm their bodies for possible immunocompromise conditions in the future. Moreover, donated blood in blood transfusion centers should be checked for possible hepatitis B virus infection using sensitive molecular tests.


Assuntos
Hepatite B , Falência Renal Crônica , Humanos , Vírus da Hepatite B/genética , Hepatite B/epidemiologia , Diálise Renal/efeitos adversos , Falência Renal Crônica/complicações , Falência Renal Crônica/epidemiologia , Falência Renal Crônica/terapia , Antígenos de Superfície da Hepatite B , Prevalência
13.
Biomed Opt Express ; 14(12): 6592-6606, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38420302

RESUMO

Diffuse Raman spectroscopy (DRS) allows subsurface molecular analysis of optically turbid samples. Numerical modeling of light propagation was used as a method for improving the design of an DRS instrument to maximize the signal to noise ratio (SNR) while ensuring safe laser exposure parameters required for in-vivo measurements. Experimental validation of the model was performed on both phantom samples and disks implanted postmortem to mimic the typical response to foreign bodies (formation of a fibrotic capsule around an implant). A reduction of laser exposure of over 1500-fold was achieved over previous studies whilst maintaining the same Raman collection rates and reaching the safe power density of 3 mW/mm2. The validation of this approach in a subcutaneous implant in a mouse cadaver showed a further improvement of 1.5-fold SNR, with a thickness limit of detection for the fibrotic layer of 23 µm, under the same acquisition times. In the animal body, a thickness limit of detection of 16 µm was achieved. These results demonstrate the feasibility of numerical model-based optimization for DRS, and that the technique can be improved sufficiently to be used for in-vivo measurement of collagenous capsule formation as a result of the foreign body response in murine models.

14.
Biomed Opt Express ; 13(10): 5275-5294, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-36425621

RESUMO

Frequency domain (FD) high density diffuse optical tomography (HD-DOT) utilising varying or combined modulation frequencies (mFD) has shown to theoretically improve the imaging accuracy as compared to conventional continuous wave (CW) measurements. Using intensity and phase data from a solid inhomogeneous phantom (NEUROPT) with three insertable rods containing different contrast anomalies, at modulation frequencies of 78 MHz, 141 MHz and 203 MHz, HD-DOT is applied and quantitatively evaluated, showing that mFD outperforms FD and CW for both absolute (iterative) and temporal (linear) tomographic imaging. The localization error (LOCA), full width half maximum (FWHM) and effective resolution (ERES) were evaluated. Across all rods, the LOCA of mFD was 61.3% better than FD and 106.1% better than CW. For FWHM, CW was 6.0% better than FD and mFD and for ERES, mFD was 1.20% better than FD and 9.83% better than CW. Using mFD data is shown to minimize the effect of inherently noisier FD phase data whilst maximising its strengths through improved contrast.

15.
Biomed Opt Express ; 13(9): 4970-4989, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36187243

RESUMO

Due to low imaging contrast, a widely-used cone-beam computed tomography-guided small animal irradiator is less adept at localizing in vivo soft tissue targets. Bioluminescence tomography (BLT), which combines a model of light propagation through tissue with an optimization algorithm, can recover a spatially resolved tomographic volume for an internal bioluminescent source. We built a novel mobile BLT system for a small animal irradiator to localize soft tissue targets for radiation guidance. In this study, we elaborate its configuration and features that are indispensable for accurate image guidance. Phantom and in vivo validations show the BLT system can localize targets with accuracy within 1 mm. With the optimal choice of threshold and margin for target volume, BLT can provide a distinctive opportunity for investigators to perform conformal biology-guided irradiation to malignancy.

16.
Neurophotonics ; 9(Suppl 2): S24001, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36052058

RESUMO

This report is the second part of a comprehensive two-part series aimed at reviewing an extensive and diverse toolkit of novel methods to explore brain health and function. While the first report focused on neurophotonic tools mostly applicable to animal studies, here, we highlight optical spectroscopy and imaging methods relevant to noninvasive human brain studies. We outline current state-of-the-art technologies and software advances, explore the most recent impact of these technologies on neuroscience and clinical applications, identify the areas where innovation is needed, and provide an outlook for the future directions.

17.
J Biomed Opt ; 27(6)2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35726130

RESUMO

SIGNIFICANCE: Bioluminescence imaging and tomography (BLT) are used to study biologically relevant activity, typically within a mouse model. A major limitation is that the underlying optical properties of the volume are unknown, leading to the use of a "best" estimate approach often compromising quantitative accuracy. AIM: An optimization algorithm is presented that localizes the spatial distribution of bioluminescence by simultaneously recovering the optical properties and location of bioluminescence source from the same set of surface measurements. APPROACH: Measured data, using implanted self-illuminating sources as well as an orthotopic glioblastoma mouse model, are employed to recover three-dimensional spatial distribution of the bioluminescence source using a multi-parameter optimization algorithm. RESULTS: The proposed algorithm is able to recover the size and location of the bioluminescence source while accounting for tissue attenuation. Localization accuracies of <1 mm are obtained in all cases, which is similar if not better than current "gold standard" methods that predict optical properties using a different imaging modality. CONCLUSIONS: Application of this approach, using in-vivo experimental data has shown that quantitative BLT is possible without the need for any prior knowledge about optical parameters, paving the way toward quantitative molecular imaging of exogenous and indigenous biological tumor functionality.


Assuntos
Medições Luminescentes , Tomografia Óptica , Algoritmos , Animais , Medições Luminescentes/métodos , Camundongos , Imagens de Fantasmas , Tomografia/métodos , Tomografia Óptica/métodos , Tomografia Computadorizada por Raios X/métodos
18.
Optica ; 9(3): 264-267, 2022 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-35340570

RESUMO

Non-invasive near-infrared spectral tomography (NIRST) can incorporate the structural information provided by simultaneous magnetic resonance imaging (MRI), and this has significantly improved the images obtained of tissue function. However, the process of MRI guidance in NIRST has been time consuming because of the needs for tissue-type segmentation and forward diffuse modeling of light propagation. To overcome these problems, a reconstruction algorithm for MRI-guided NIRST based on deep learning is proposed and validated by simulation and real patient imaging data for breast cancer characterization. In this approach, diffused optical signals and MRI images were both used as the input to the neural network, and simultaneously recovered the concentrations of oxy-hemoglobin, deoxy-hemoglobin, and water via end-to-end training by using 20,000 sets of computer-generated simulation phantoms. The simulation phantom studies showed that the quality of the reconstructed images was improved, compared to that obtained by other existing reconstruction methods. Reconstructed patient images show that the well-trained neural network with only simulation data sets can be directly used for differentiating malignant from benign breast tumors.

19.
J Biophotonics ; 15(7): e202200041, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35340113

RESUMO

There is an urgent need for improved respiratory surveillance of preterm infants. Gas in scattering media absorption spectroscopy (GASMAS) is emerging as a potential clinical cutaneous monitoring tool of lung functions in neonates. A challenge in the clinical translation of GASMAS is to obtain sufficiently high signal-to-noise ratios in the measurements, since the light attenuation is high in human tissue. Previous GASMAS studies on piglets have shown higher signal quality with an internal source, as more light propagates through the lung and the loss due to scattering and absorption is less. In this article we simulated light propagation with an intratracheal and a dermal source, and investigated the signal quality and lung volume probed. The results suggest that GASMAS has the potential to measure respiratory volumes; and the sensitivity is higher for an intratracheal source which also enables to probe most of the lung.


Assuntos
Recém-Nascido Prematuro , Oxigênio , Animais , Humanos , Recém-Nascido , Pulmão , Medidas de Volume Pulmonar , Análise Espectral/métodos , Suínos
20.
J Biomed Opt ; 27(7)2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35043610

RESUMO

SIGNIFICANCE: Time-domain functional near-infrared spectroscopy (TD-fNIRS) has been considered as the gold standard of noninvasive optical brain imaging devices. However, due to the high cost, complexity, and large form factor, it has not been as widely adopted as continuous wave NIRS systems. AIM: Kernel Flow is a TD-fNIRS system that has been designed to break through these limitations by maintaining the performance of a research grade TD-fNIRS system while integrating all of the components into a small modular device. APPROACH: The Kernel Flow modules are built around miniaturized laser drivers, custom integrated circuits, and specialized detectors. The modules can be assembled into a system with dense channel coverage over the entire head. RESULTS: We show performance similar to benchtop systems with our miniaturized device as characterized by standardized tissue and optical phantom protocols for TD-fNIRS and human neuroscience results. CONCLUSIONS: The miniaturized design of the Kernel Flow system allows for broader applications of TD-fNIRS.


Assuntos
Encéfalo , Espectroscopia de Luz Próxima ao Infravermelho , Encéfalo/diagnóstico por imagem , Humanos , Espectroscopia de Luz Próxima ao Infravermelho/métodos
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