Takeshi Namita

© 2018 Author(s). Photoacoustic imaging comprises an optical excitation within a target zone and the detection of the ultrasonic wave so created. A pulsed laser illuminates the target zone, and this illumination causes rapid thermoelastic expansio...

© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. Photoacoustic imaging is anticipated for use in portraying blood vessel structures (e.g. neovascularization in inflamed regions). To reduce invasiveness and enhance ...

© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. For early diagnosis of rheumatoid arthritis (RA), it is important to visualize its potential marker, vascularization in the synovial membrane of the finger joints. P...

© 2017 IEEE. In chronic hepatitis diagnosis, shear wave elastography is utilized for evaluating fibrosis progression. It is expected that the accuracy will be improved by measuring the viscosity in addition to the elasticity. However, the shear wa...

© 2017 IEEE. Shear wave elastography is useful for quantitatively evaluating tissue elasticity by measuring the speed of a shear wave induced within the body by acoustic radiation force. We proposed a pushing-and-tracking sequence, coded push-puls...

© 2017 IEEE. In recent years, skin aging caused by ultraviolet light exposure (i.e. photoaging) has garnered attention in the fields of beauty and health care because photoaging accelerates skin aging. However, few practical techniques exist for t...

© 2017 SPIE.Diabetes, a typical lifestyle-related disease, is an important disease presenting risks of various complications such as retinopathy, kidney failure, and nervous neuropathy. To treat diabetes, regular and continual self-measurement of ...

© 2017 SPIE.Photoacoustic imaging has garnered constant attention as a non-invasive modality for visualizing details of the neovascularization structure of tumors, or the distribution of oxygen saturation, which is related to the tumor grade. Howe...

© 2016 SPIE.Patients affected by diseases caused by arteriosclerosis are increasing. Atherosclerosis, which is becoming an especially difficult health problem, forms plaques from lipids such as cholesterol located in walls of the aorta, cerebral a...

A constant sound speed (i.e., 1540 m/s) is generally used in various ultrasound (US) and photoacoustic (PA) image reconstruction algorithms based on the assumption of a homogeneous sound speed in human tissue. However, the variation of the sound s...

To realize practical optical communication through human body, an experimental study was conducted on the near-infrared light propagation through model phantoms and a human hand. In the experiment with the phantom, it was found that the longer com...

To improve the transcutaneous fluorescent image of an animal body, we derived a point-spread function (PSF) at a cylindrical surface of a diffuse scattering medium. For practical applications, a new CT algorithm was developed. In this technique, a...

We have analyzed the beam-wave propagation in random media, and applied it to the transillumination imaging using practically useful light-beam illumination. However, the capability of the technique was not sufficient with respect to the scatterin...

To realize practical optical communication through human body, an experimental study was conducted on the near-infrared light propagation through model phantoms and a human hand. In the experiment with the phantom, it was found that the longer com...

To improve the transcutaneous fluorescent image of an animal body, we derived a point-spread function (PSF) at a cylindrical surface of a diffuse scattering medium. For practical applications, a new CT algorithm was developed. In this technique, a...

We have analyzed the beam-wave propagation in random media, and applied it to the transillumination imaging using practically useful light-beam illumination. However, the capability of the technique was not sufficient with respect to the scatterin...

© 2015 SPIE. Photoacoustic Computed Tomography (PACT) records signals from a wide range of angles to achieve uniform, highresolution images. A high-power laser is generally used for PACT, but the long acquisition time with a single probe is a prob...

© 2015 SPIE. We have proposed a new nonlinear inversion technique to estimate the spatial distribution of the absorption coefficient (μa) in the depth direction of a turbid medium by spatially resolved backscattering measurement. With this techniq...

To realize three-dimensional optical imaging using transillumination images, we developed a novel technique to suppress the scattering effect in a transillumination image and reconstruct a three-dimensional image of the internal light-absorbing st...

For optical observation of arteriovenous fistula in dialysis treatment, we have developed a transmission image improvement technique using the measured point spread function (PSF) of implanted fluorescent source inside the body. In the experimenta...

To improve the transcutaneous fluorescent image of an animal body, we derived a point-spread function (PSF) at a cylindrical surface of a diffuse scattering medium. In this technique, distortion problem of the restored shape was remained. To solve...

We have developed a technique to estimate the spatial distribution of the absorption coefficient (μ_a) of turbid medium by the time-resolved measurement of backscattered light, and verified its feasibility in simulation and experiments. For accura...

To improve near-infrared transillumination images of biological tissue, a new scattering suppression technique was developed. It enables us to apply the point spread function (PSF) derived for light source to the transillumination image of an abso...

To realize three-dimensional (3D) optical imaging of the internal structure of animal body, we have developed a new technique to reconstruct CT images from two-dimensional (2D) transillumination images. In transillumination imaging, the image is b...

To examine the practical potential of an optical body area network (BAN) technique, a feasibility study was conducted of optical data transmission through a human hand using diffusely scattered light. The data transmission of 170 mm distance in a ...

The absorption at a specific position inside a turbid medium can be measured by back-propagating the scattered light using phase conjugate light and focused ultrasonic modulation. With the view toward clear imaging through turbid medium, we constr...

For the 3D non-invasive imaging of shallow regions of a human body, we have developed a new technique to reconstruct the absorbing structure from optical transillumination images obtained in limited view angle. The effectiveness of the proposed te...

To realize the tissue oxygen saturation imaging by time-resolved measurement of backscattered light, appropriate wavelengths have been chosen from the absorption spectrum of hemoglobin. For the precise estimation in the medium with spatially inhom...

To obtain a clear image in transcutaneous fluorescent imaging, we have newly developed a technique to simultaneously estimate the depth and optical coefficients which have to be known a priori to improve fluorescent images. The feasibility of the ...

To realize the practical transillumination imaging with beam-wave incidence. we had derived the equation of beam-wave propagation in a turbid medium theoretically, and formulated the procedure of image processing. The validity and effectiveness of...

To realize practical optical communication through human body, an experimental study was conducted on the near-infrared light propagation through model phantoms and a human hand. In a backscattering configuration, the optical data transmission ove...

A technique was newly developed to estimate the thickness of a fluorescent object in a turbid medium, such as an animal body. In this technique. we estimate the thickness from the different in the fluorescent intensity caused by the difference in ...

We have shown the possibility of transillumination imaging of the arteries in the adult forearm as well as the veins. Using the change of absorption spectra of blood hemoglobin, we can expect to discriminate the arteries from the veins in the tran...

To improve the transcutaneous fluorescent image of an animal body, we derived the depth dependent point-spread function (PSF) for the fluorescent object in scattering medium and demonstrated scattering suppression technique using the depth depende...

To investigate the relevance between the sleep apnea and the sleep bruxism (SB), we devised an algorithm to detect the occurrence of SB in the EMG of masseter muscle. EMG waveforms of SB were extracted based on the temporal change of the degree of...

The absorption distribution along the depth direction in a turbid medium can be estimated in the time-resoloved measurement. For accurate estimation of the absorption distribution in scattering medium, a new technique which is applicable even to l...

To improve NIR transillumination images of animal body, the application of the point spread function (PSF) derived for fluorescent source inside the body was attempted. Through experimental study, the applicability was demonstrated. In addition, t...

The transillumination image of blood vessels for vein authentication are blurred by the strong scattering of the body tissue. Scattering and absorption property of biological tissue depends on the wavelength. A technique was newly developed to imp...

A dynamic light scattering (DLS) technique has been applied to quantify the amount of the small dense low-density lipoprotein (sdLDL) which is clinically significant for coronary diseases. A technique to obtain the size distribution of LDL particl...

We have developed a technique to estimate the absorption coefficient (μ_a) of turbid medium by the time-resolved measurement of backscattered light, and verified its feasibility in simulation and experiments. For accurate estimation of the absorpt...

To see through a turbid medium, a technique was developed to reconstruct a three-dimensional structure inside the medium. Clear transillumination images were obtained with a scattering suppression technique in which the weakly scattered light comp...

To assist vascular injection, we have developed a simultaneous observation system using a body surface image and a transillumination image of blood vessels. Light source was devised to make homogeneous, wide-area and low-leak illumination possible...

The possibility of new biological measurement by time resolved analysis of the optical backscattering enhancement was pursued. Through simulation analysis for various optical parameter changes, the extinction time of the enhancement peak was selec...

To realize functional imaging by time-resolved measurement of backscattered light, a technique has been developed to estimate the spatial distribution of tissue oxygen saturation. In theoretical analysis on the estimation error, the measurement co...

We developed a technique to estimate the reduced scattering coefficient (μ_s') of turbid medium by the time-resolved measurement of backscattered light, and verified its feasibility in simulation. Here, we examined the accuracy and the characteris...

The amount of small dense low density lipoprotein (sdLDL) is known to have high correlation with coronary diseases. To realize a practical quantitative evaluation of sdLDL, we applied the dynamic light scattering (DLS) technique. Three methods wer...

For cross-sectional imaging of an animal body, the technique using backscattered light and repetitive inverse solution was developed. The effectiveness of the new technique was verified in simulation and the experiment using biological tissue. ©20...

The backscattering enhancement has been studied with continuous light. We attempted the time-resolved analysis for this phenomenon. It was newly found that the width of the backscattering enhancement peak becomes narrower as time goes in the risin...

A technique was developed to estimate the scattering coefficient of diffuse medium such as a biological body by the time-resolved measurement of backscattered light. The effectiveness of the technique was confirmed in the Monte Carlo simulation. I...