Listen to photon propagation in biological tissues: quantitative optical scattering imaging and high-resolution diffuse optical tomography using photoacoustic measurements

2014 ◽  
Author(s):  
Zhen Yuan
Author(s):  
Yongyi Zhao ◽  
Ankit Raghuram ◽  
Hyun Kim ◽  
Andreas Hielscher ◽  
Jacob T Robinson ◽  
...  

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252036
Author(s):  
Xiaoxue Fu ◽  
John E. Richards

Diffuse optical tomography uses near-infrared light spectroscopy to measure changes in cerebral hemoglobin concentration. Anatomical interpretations of the location that generates the hemodynamic signal requires accurate descriptions of diffuse optical tomography sensitivity to the underlying cortical structures. Such information is limited for pediatric populations because they undergo rapid head and brain development. The present study used photon propagation simulation methods to examine diffuse optical tomography sensitivity profiles in realistic head models among infants ranging from 2 weeks to 24 months with narrow age bins, children (4 and 12 years) and adults (20 to 24 years). The sensitivity profiles changed systematically with the source-detector separation distance. The peak of the sensitivity function in the head was largest at the smallest separation distance and decreased as separation distance increased. The fluence value dissipated more quickly with sampling depth at the shorter source-detector separations than the longer separation distances. There were age-related differences in the shape and variance of sensitivity profiles across a wide range of source-detector separation distances. Our findings have important implications in the design of sensor placement and diffuse optical tomography image reconstruction in (functional) near-infrared light spectroscopy research. Age-appropriate realistic head models should be used to provide anatomical guidance for standalone near-infrared light spectroscopy data in infants.


Author(s):  
Yasuomi Endo ◽  
Yukari Tanikawa ◽  
Shinpei Okawa ◽  
Kazuto Masamoto ◽  
Hidetaka Okada ◽  
...  

Light in the near-infrared wavelength range can penetrate deeping into biological tissues because the absorption by both water and hemoglobin is much smaller than in the other wavelength ranges. Oxygenated and deoxygenated hemoglobins have different light absorption characteristics. Therefore, by obtaining tomographic images of the absorption characteristics, it will be possible to know the hemodynamics inside deep tissues. Thus, the diffuse optical tomography (DOT) is expected as a new modality of biomedical imaging. In this study, we try to obtain DOT images of the forearms by conducting two types of exercise, and their differences caused by the muscle activity are discussed. By comparing the reconstructed DOT images with the magnetic resonance images of the forearm at the same position, the activated muscles can be identified in detail. As a result, the hemodynamics in the dominant muscles when performing flexion and extension of wrist are observed.


2002 ◽  
Author(s):  
Alexander B. Konovalov ◽  
Vladimir V. Lyubimov ◽  
Igor I. Kutuzov ◽  
Olga V. Kravtsenyuk ◽  
Alexander G. Murzin ◽  
...  

2020 ◽  
Author(s):  
Xiaoxue Fu ◽  
John E. Richards

AbstractSignificanceDiffuse optical tomography (DOT) uses near-infrared light spectroscopy (NIRS) to measure changes in cerebral hemoglobin concentration. Anatomical interpretations of NIRS data requires accurate descriptions of the cranio-cerebral relations and DOT sensitivity to the underlying cortical structures. Such information is limited for pediatric populations because they undergo rapid head and brain development.AimThe present study aimed to investigate age-related differences in scalp-to-cortex distance and mapping between scalp locations and cortical regions of interest (ROIs) among infants (2 weeks to 24 months with narrow age bins), children (4 and 12 years) and adults (20 to 24 years).ApproachWe used spatial scalp projection and photon propagation simulation methods with age-matched realistic head models based on MRIs.ResultsThere were age-group differences in the scalp-to-cortex distances in infancy. The developmental increase was magnified in children and adults. There were systematic age-related differences in the probabilistic mappings between scalp locations and cortical ROIs.ConclusionsOur findings have important implications in the design of sensor placement and making anatomical interpretations in NIRS and fNIRS research. Age-appropriate realistic head models should be used to provide anatomical guidance for standalone DOT data in infants.


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