The intrinsic markers of nanoscale morphological alteration in fixed tissue biopsy referred to as disorder strength and local correlation length, which can be easily and time-efficiently obtained from quantitative phase images, are introduced. After presenting how to extract these markers from quantitative phase images obtained by highly sensitive quantitative phase imaging system, spatial light interference microscopy (SLIM), we demonstrate the effectiveness of these markers for diagnosis of benign and malignant breast tissues.
We propose an intrinsic cancer marker in fixed tissue biopsy slides, which is based on the local spatial autocorrelation length obtained from quantitative phase images. The spatial autocorrelation length in a small region of the tissue phase image is sensitive to the nanoscale cellular morphological alterations and can hence inform on carcinogenesis. Therefore, this metric can potentially be used as an intrinsic cancer marker in histopathology. Typically, these correlation length maps are calculated by computing two-dimensional Fourier transforms over image subregions—requiring long computational times. We propose a more time-efficient method of computing the correlation map and demonstrate its value for diagnosis of benign and malignant breast tissues. Our methodology is based on highly sensitive quantitative phase imaging data obtained by spatial light interference microscopy.
Quantitative phase imaging (QPI) can access quantitative information on thickness and/or refractive index changes of weakly absorbing and scattering objects, which normally require staining prior to observation. The quantitative phase image itself yields significant information for a medical diagnosis, particularly in cancer biopsies. Previously, several parameters such as a local standard deviation of refractive index have been utilized as a marker of diseases. We focus on the local spatial autocorrelation length, which is calculated at each point in the field of view. The local spatial autocorrelation length is defined as the standard deviation of the local spatial autocorrelation function and reveals the local and directional disorder information of tissues. However, generally, a direct calculation of the local spatial autocorrelation length take an immense amount of time. In this paper, we propose a high-throughput calculation procedure of a local spatial autocorrelation length, by exploiting frequency-domain calculations. After deriving a simple equation to calculate the local spatial autocorrelation length map in a short time, we perform label-free screening of benign and malignant breast tissue biopsies using this parameter as a marker.
The standard method for cancer diagnosis is the microscopic investigation of tissue biopsies. Because the tissues do not significantly absorb and scatter light, traditionally, the observation is performed using bright-field microscopy after staining. Although this approach has been widely adopted all over the world for 100 years, it generally takes a long preparation time and sometimes the early carcinogenesis is missed due to a variation in a quality of a staining. Quantitative phase imaging (QPI) can access objective information on thickness and refractive index changes from an unstained tissue slice, which cannot be observed by conventional microscopes. This can be an attractive advantage in the field of a medical diagnosis, especially since QPI can access the tissue architecture information with nanoscale sensitivity. In this paper, we used quantitative phase imaging to measure the tissue disorder strength, which is known as one of the effective markers of early carcinogenesis. We retrieved the disorder parameter from the local refractive index fluctuation map obtained by spatial light interference microscopy (SLIM). We show that SLIM imaging combined with the disorder analysis is a valuable approach for screening of benign and malignant breast tissue biopsies.
Since the optical inter-satellite communication has attractive advantages such as high-speed transmission with high
confidence, almost no electronic magnetic interference, and low power consumption, it has been activity investigated.
However, directivity control of the laser beams requires a bulky and complicated system in satellite mobile
communications. A more flexible and high accurate system with small and simple mechanism has been desired. In this
study, we propose a new method of optical inter-satellite communication with a dynamically reconfigurable optical
directional device in which diffraction gratings are automatically rewritten and reorganized in response of incident
conditions by moving satellites. For realizing such a device, we have developed Sn2P2S6 crystals which have a high
sensitive photorefractivity and dynamic reconfigurable property. Furthermore, this crystal has hundreds times faster
response than conventional photorefractive materials such as BaTiO3. These features are extremely advantageous to
construct a high-speed and flexible communication system with a large tolerance to displacement of moving satellites.
To investigate the possibility of the dynamically reconfigurable optical inter-satellite communication system, we
experimentally evaluate the temporal and spatial characteristics of Sn2P2S6 crystals for the variation of the beam incident
angle. Moreover, the diffraction beam from the crystal has phase conjugate wavefronts of the beam entering from the
counter direction. We try to utilize this behavior to suppress the beam spread and to reduce the background light such as
sunlight with a spatial filtering technique that has sensitivity in wavefront differences of the signal and background light.
We develop a tunable optical wavelength filter with PR (photorefractive) materials applied the external field for
achieving higher sensitivity and efficiency. In the past, the diffraction efficiency of the PR tunable filters with
transmission gratings has been much lower than other conventional wavelength filters, such as the array wavelength
gratings filter, the thin film filter, and the fiber Bragg gratings filter. By applying the external field to PR materials, we
can obtain the refractive index modulation depth of 13 times larger than that without applied field, specifically in lithium
niobate with the acceptor density of ~1022 [1/m3] and the voltage of 10 [kV/cm]. Our PR tunable filter provides
reconfigurable wavelength routing of the signal beam since the various diffraction gratings can be immediately induced
and multiplexed by changing incident conditions of two coherent writing beams viewpoint in comparing experimental
results to numerical simulations, and can be rewritten dynamically through the PR effect. These advantages allow us to
achieve more flexible optical net work based on the wavelength division multiplexing technique. In this work, we
calculate the relationship between the diffraction efficiency and the magnitude of the applied external field by solving
coupled wave equations in the case of lithium niobate, respectively.
KEYWORDS: Holography, Data storage, Fourier transforms, Holographic data storage systems, Energy efficiency, Phase shift keying, Signal detection, Spatial light modulators, Near field optics, Holograms
We develop a photorefractive time-domain differential detection (PR-TDDD) method in holographic data storage
systems with considering the temporal response of photorefractive two-wave mixing (PR-TWM). Optimizing the
parameters of PR-TDDD method provides high-precision distinction of phase-modulated signals, i.e. distinction of small
phase difference. In PR-TDDD method, the phase information can be sequentially-distinguished by monitoring the
output intensity of PR-TWM. This is because the output intensity of PR-TWM is changed when the signal phase is
changed. In addition, the changing rate of the output intensity corresponds to that of the signal phase. The advantages of
our method are high energy efficiency, alignment-free optics and the distinction of multi-valued phase-modulated signals.
Especially, we focus attention on applying to phase-based holographic data storage systems, which can achieve
homogeneous intensity distribution on recording plane, i.e. Fourier transform plane, in general, and high energy
efficiency because of 100% white rate. More noteworthy is that multi-valued phase-based holographic data storage can
be realized by using PR-TDDD method. In this work, we consider the important parameters in PR-TDDD method;
signal-to-pump beam intensity ratio, photorefractive coupling strength, and photorefractive time constant. The balance
between these parameters is important for realizing the high-precision distinction of phase-modulated signal.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.