LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 155

Search options

  1. Article: Near-Infrared Transillumination for Macroscopic Functional Imaging of Animal Bodies.

    Shimizu, Koichi

    Biology

    2023  Volume 12, Issue 11

    Abstract: The classical transillumination technique has been revitalized through recent advancements in optical technology, enhancing its applicability in the realm of biomedical research. With a new perspective on near-axis scattered light, we have harnessed near- ...

    Abstract The classical transillumination technique has been revitalized through recent advancements in optical technology, enhancing its applicability in the realm of biomedical research. With a new perspective on near-axis scattered light, we have harnessed near-infrared (NIR) light to visualize intricate internal light-absorbing structures within animal bodies. By leveraging the principle of differentiation, we have extended the applicability of the Beer-Lambert law even in cases of scattering-dominant media, such as animal body tissues. This approach facilitates the visualization of dynamic physiological changes occurring within animal bodies, thereby enabling noninvasive, real-time imaging of macroscopic functionality in vivo. An important challenge inherent to transillumination imaging lies in the image blur caused by pronounced light scattering within body tissues. By extracting near-axis scattered components from the predominant diffusely scattered light, we have achieved cross-sectional imaging of animal bodies. Furthermore, we have introduced software-based techniques encompassing deconvolution using the point spread function and the application of deep learning principles to counteract the scattering effect. Finally, transillumination imaging has been elevated from two-dimensional to three-dimensional imaging. The effectiveness and applicability of these proposed techniques have been validated through comprehensive simulations and experiments involving human and animal subjects. As demonstrated through these studies, transillumination imaging coupled with emerging technologies offers a promising avenue for future biomedical applications.
    Language English
    Publishing date 2023-10-24
    Publishing country Switzerland
    Document type Journal Article ; Review
    ZDB-ID 2661517-4
    ISSN 2079-7737
    ISSN 2079-7737
    DOI 10.3390/biology12111362
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article: Erratum: Optical parameters estimation in inhomogeneous turbid media using backscattered light: for transcutaneous scattering measurement of intravascular blood: erratum.

    Liang, Shiyang / Miyake, Takeo / Shimizu, Koichi

    Biomedical optics express

    2024  Volume 15, Issue 2, Page(s) 910

    Abstract: This corrects the article on p. 237 in vol. 15, PMID: 38223194.]. ...

    Abstract [This corrects the article on p. 237 in vol. 15, PMID: 38223194.].
    Language English
    Publishing date 2024-01-19
    Publishing country United States
    Document type Published Erratum
    ZDB-ID 2572216-5
    ISSN 2156-7085
    ISSN 2156-7085
    DOI 10.1364/BOE.517856
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article: Optical parameters estimation in inhomogeneous turbid media using backscattered light: for transcutaneous scattering measurement of intravascular blood.

    Liang, Shiyang / Miyake, Takeo / Shimizu, Koichi

    Biomedical optics express

    2023  Volume 15, Issue 1, Page(s) 237–255

    Abstract: In our earlier research, a technique was developed to estimate the effective attenuation coefficient of subcutaneous blood vessels from the skin surface using the spatial distribution of backscattered near-infrared (NIR) light. The scattering effect in ... ...

    Abstract In our earlier research, a technique was developed to estimate the effective attenuation coefficient of subcutaneous blood vessels from the skin surface using the spatial distribution of backscattered near-infrared (NIR) light. The scattering effect in surrounding tissues was suppressed through the application of a differential principle, provided that the
    Language English
    Publishing date 2023-12-15
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2572216-5
    ISSN 2156-7085
    ISSN 2156-7085
    DOI 10.1364/BOE.510245
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Book: Current aspects in ophthalmology / 1

    Shimizu, Kōichi

    Kyoto, 12 - 17 May 1991

    1992  

    Author's details ed. Koichi Shimizu
    Collection Current aspects in ophthalmology
    Size LIII, 943 S. : Ill., graph. Darst.
    Publisher Excerpta Medica
    Publishing place Amsterdam u.a.
    Publishing country Netherlands
    Document type Book
    HBZ-ID HT004449156
    Database Catalogue ZB MED Medicine, Health

    Kategorien

  5. Book: Current aspects in ophthalmology / 2

    Shimizu, Kōichi

    Kyoto, 12 - 17 May 1991

    1992  

    Author's details ed. Koichi Shimizu
    Collection Current aspects in ophthalmology
    Size XVII S., S. 947 - 1900 : Ill., graph. Darst.
    Publisher Excerpta Medica
    Publishing place Amsterdam u.a.
    Publishing country Netherlands
    Document type Book
    HBZ-ID HT004449163
    Database Catalogue ZB MED Medicine, Health

    Kategorien

  6. Article ; Online: Reconstructing a Deblurred 3D Structure in a Turbid Medium from a Single Blurred 2D Image-For Near-Infrared Transillumination Imaging of a Human Body.

    Shimizu, Koichi / Xian, Sihan / Guo, Jiekai

    Sensors (Basel, Switzerland)

    2022  Volume 22, Issue 15

    Abstract: To provide another modality for three-dimensional (3D) medical imaging, new techniques were developed to reconstruct a 3D structure in a turbid medium from a single blurred 2D image obtained using near-infrared transillumination imaging. One technique ... ...

    Abstract To provide another modality for three-dimensional (3D) medical imaging, new techniques were developed to reconstruct a 3D structure in a turbid medium from a single blurred 2D image obtained using near-infrared transillumination imaging. One technique uses 1D information of a curvilinear absorber, or the intensity profile across the absorber image. Profiles in different conditions are calculated by convolution with the depth-dependent point spread function (PSF) of the transillumination image. In databanks, profiles are stored as lookup tables to connect the contrast and spread of the profile to the absorber depth. One-to-one correspondence from the contrast and spread to the absorber depth and thickness were newly found. Another technique uses 2D information of the transillumination image of a volumetric absorber. A blurred 2D image is deconvolved with the depth-dependent PSF, thereby producing many images with points of focus on different parts. The depth of the image part can be estimated by searching the deconvolved images for the image part in the best focus. To suppress difficulties of high-spatial-frequency noise, we applied a noise-robust focus stacking method. Experimentation verified the feasibility of the proposed techniques, and suggested their applicability to curvilinear and volumetric absorbers such as blood vessel networks and cancerous lesions in tissues.
    MeSH term(s) Human Body ; Humans ; Imaging, Three-Dimensional/methods ; Phantoms, Imaging ; Transillumination/methods
    Language English
    Publishing date 2022-08-01
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2052857-7
    ISSN 1424-8220 ; 1424-8220
    ISSN (online) 1424-8220
    ISSN 1424-8220
    DOI 10.3390/s22155747
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article ; Online: Quantitative analyses of RBC movement in whole blood exposed to DC and ELF electric field.

    Kanemaki, Miki / Shimizu, Hisae O / Inujima, Hiroshi / Miyake, Takeo / Shimizu, Koichi

    Bioelectromagnetics

    2023  Volume 45, Issue 4, Page(s) 159–170

    Abstract: For the study of biological effects of direct current (DC) and extremely low frequency (ELF) electric fields, we have quantitatively analyzed red blood cell (RBC) movement in whole blood. Considering the inhomogeneous distribution of electric fields in ... ...

    Abstract For the study of biological effects of direct current (DC) and extremely low frequency (ELF) electric fields, we have quantitatively analyzed red blood cell (RBC) movement in whole blood. Considering the inhomogeneous distribution of electric fields in vivo, five different electric field distributions were generated under a microscope. For theoretical analyses, we assumed electrophoresis and dielectrophoresis as basic motive forces and obtained the spatial distribution of blood cell velocity. The RBC velocity was measured using video image analysis. The spatial dependence of the velocity showed good agreement with that predicted by theoretical analysis. This result suggests the validity of the theoretical model based on electrophoresis and dielectrophoresis for the study of ELF electric field exposure to inhomogeneous animal and human bodies. Next, using the same measurement system, we attempted to find the electric field strength at which these effects occur. The threshold values were found to be 0.40 and 1.6 kV/m, respectively, for DC and AC electric field exposures. Furthermore, we investigated the reproducibility of the field effects in more realistic conditions of human exposure. The RBCs in microchannels were exposed to the electric field generated in capacitive coupling using electrodes separated by an air gap. Even in the new condition, similar effects were observed, which also verified the validity of the analysis described above. These results will provide useful information for the safety assessment of field exposure and for the future biomedical applications of electric fields to manipulate RBCs in vivo.
    MeSH term(s) Animals ; Humans ; Electromagnetic Fields/adverse effects ; Reproducibility of Results ; Erythrocytes ; Electricity ; Models, Theoretical
    Language English
    Publishing date 2023-12-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 760683-7
    ISSN 1521-186X ; 0197-8462
    ISSN (online) 1521-186X
    ISSN 0197-8462
    DOI 10.1002/bem.22493
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  8. Book ; Conference proceedings: Fluorescein Angiography

    Shimizu, Kōichi

    proceedings of the International Symposium on fluorescein angiography (ISFA), Tokyo 1972

    1974  

    Event/congress International Symposium on Fluorescein Angiography (1972, Tokio)
    Author's details ed. by Koichi Shimizu
    Language English
    Size XIX, 449 S. ; 4-o
    Publisher Igaku Shoin
    Publishing place Tokyo
    Publishing country Japan
    Document type Book ; Conference proceedings
    HBZ-ID HT008560282
    Database Catalogue ZB MED Medicine, Health

    Kategorien

  9. Article: Three-dimensional imaging through turbid media using deep learning: NIR transillumination imaging of animal bodies.

    Phan Van, To Ni / Tran, Trung Nghia / Inujima, Hiroshi / Shimizu, Koichi

    Biomedical optics express

    2021  Volume 12, Issue 5, Page(s) 2873–2887

    Abstract: Using near-infrared (NIR) light with 700-1200 nm wavelength, transillumination images of small animals and thin parts of a human body such as a hand or foot can be obtained. They are two-dimensional (2D) images of internal absorbing structures in a ... ...

    Abstract Using near-infrared (NIR) light with 700-1200 nm wavelength, transillumination images of small animals and thin parts of a human body such as a hand or foot can be obtained. They are two-dimensional (2D) images of internal absorbing structures in a turbid medium. A three-dimensional (3D) see-through image is obtainable if one can identify the depth of each part of the structure in the 2D image. Nevertheless, the obtained transillumination images are blurred severely because of the strong scattering in the turbid medium. Moreover, ascertaining the structure depth from a 2D transillumination image is difficult. To overcome these shortcomings, we have developed a new technique using deep learning principles. A fully convolutional network (FCN) was trained with 5,000 training pairs of clear and blurred images. Also, a convolutional neural network (CNN) was trained with 42,000 training pairs of blurred images and corresponding depths in a turbid medium. Numerous training images were provided by the convolution with a point spread function derived from diffusion approximation to the radiative transport equation. The validity of the proposed technique was confirmed through simulation. Experiments demonstrated its applicability. This technique can provide a new tool for the NIR imaging of animal bodies and biometric authentication of a human body.
    Language English
    Publishing date 2021-04-23
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2572216-5
    ISSN 2156-7085
    ISSN 2156-7085
    DOI 10.1364/BOE.420337
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article ; Online: Analysis of Red Blood Cell Movement in Whole Blood Exposed to DC and ELF Electric Fields.

    Kanemaki, Miki / Shimizu, Hisae O / Inujima, Hiroshi / Miyake, Takeo / Shimizu, Koichi

    Bioelectromagnetics

    2022  Volume 43, Issue 3, Page(s) 149–159

    Abstract: To evaluate hematological effects of direct current (DC) and alternating current (AC) extremely low frequency (ELF) electric field exposure, this study investigated red blood cell (RBC) movement in whole blood. Video images of RBCs were recorded under a ... ...

    Abstract To evaluate hematological effects of direct current (DC) and alternating current (AC) extremely low frequency (ELF) electric field exposure, this study investigated red blood cell (RBC) movement in whole blood. Video images of RBCs were recorded under a microscope using specially designed electrode systems. Video analysis software was then used to measure the RBC velocity. The noise level and measurement system stability were confirmed based on results of a no-field exposure experiment. Using the electrode system to produce a non-homogeneous electric field, different movements were found to occur in DC and AC field exposure. The RBCs moved in the directions of the electric field and the gradient of field distribution, respectively, in the DC and AC fields. Dependences of the RBC velocity on the field strength were, respectively, linear and quadratic in the DC and AC fields. These results suggest that electrophoretic and dielectrophoretic movements were, respectively, dominant in the DC and AC fields. The magnitude of the electric field necessary to cause these effects was found to be 10
    MeSH term(s) Cell Movement ; Electricity ; Erythrocytes ; Humans ; Movement
    Language English
    Publishing date 2022-05-16
    Publishing country United States
    Document type Journal Article
    ZDB-ID 760683-7
    ISSN 1521-186X ; 0197-8462
    ISSN (online) 1521-186X
    ISSN 0197-8462
    DOI 10.1002/bem.22395
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top