The capabilities of ultrasound optical tomography (UOT) is investigated through Monte Carlo simulations on realistic breast tissue phantoms constructed using the OpenVCT platform. This work indicates that UOT is a method capable of distinguishing malignant tumor tissue from benign glandular tissue deep inside the breast, despite the natural variations of adipose and glandular compartments within a breast or between breasts with different volume breast densities.
Each year, about 30% of all newly diagnosed cancer cases in women worldwide are breast cancers [1]. One of the most common techniques for breast cancer diagnosis is mammography. However, this technique provides limited functional information regarding breast tissue morphology. In cases of suspected malignancy invasive techniques such as biopsy are implemented.
In this work an optical deep tissue imaging technique called ultrasound optical tomography (UOT) which combines laser light and ultrasound is implemented for a non-invasive lesion (tumour) characterization in breast tissue.
The experiments were performed using 794 nm laser wavelength, 6 MHz ultrasound frequency and a narrowband spectral filter material, Tm3+:LiNbO3. The measurements were carried out in 5 cm thick agar phantoms using a range of tumor mimicking inclusions of 3 different sizes.
This work is the first deep tissue imaging demonstration using UOT at tissue relevant wavelengths. Current results indicate that the UOT technique can become an important and valuable tool for lesion characterization in breast tissue.
Ultrasound Optical Tomography (UOT) combines the high-resolution imaging capability of ultrasound with measurements of light absorption and scattering properties of human tissue. This non-invasive technique could distinguish between cancerous and non-cancerous lesions inside the breast tissue, follow tumor shrinkage during pre-operative treatment, or provide information on blood oxygenation levels. Recent measurements of phantoms mimicking the optical properties of breast tissue with various lesions indicated that the technique can probe 50 mm deep through the tissue. This work concentrates on developing the UOT setup in transmission mode and discusses its advantages, limitations, and possible improvements.
Optical imaging utilize light to analyze biological tissues in detail, non-invasively and without harmful radiation. Examples include ultrasound optical tomography and photoacoustic imaging; both use a limited number of wavelengths. Diffuse reflectance spectroscopy, another optical technique, covers a continuous wavelength range, but without generating an image. This study focuses on extended-wavelength DRS (450 to 1550nm) to compare healthy breast tissue with different subgroups of breast cancer. Analysis of 13 breast specimens with invasive ductal or lobular carcinoma reveals distinct optical profiles in tumor subgroups compared to healthy tissue. However, absorption and scattering patterns are similar among the tumor subgroups.
We present and validate a simulation package for simulating the signal generated from arbitrary acousto-optical interaction in scattering media. We further present an example on how the package can be used as a virtual lab.
Biological tissue is a highly scattering medium that prevents deep imaging of light. For medical applications, optical imaging offers a molecular sensitivity that would be beneficial for diagnosing and monitoring of diseases. Acousto-optical tomography has the molecular sensitivity of optical imaging with the resolution of ultrasound and has the potential for deep tissue imaging. Here, we present a theoretical study of a system that combines acousto-optical tomography and slow light spectral filters created using spectral hole burning methods. Using Monte Carlo simulations, a model to obtain the contrast-to-noise ratio (CNR) deep in biological tissue was developed. The simulations show a CNR > 1 for imaging depths of ∼5 cm in a reflection mode setup, as well as, imaging through ∼12 cm in transmission mode setups. These results are promising and form the basis for future experimental studies.
Solid state quantum computer hardware may be based on rare-earth-ion-doped crystals. The qubits can
be encoded as nuclear spin states of an ensemble of, e.g., Pr3+ ions, randomly doped into a Y2SiO5 crystal.
Two such qubits can control each other through the dipole blockade effect, and transfers between the two
qubit states can be done at a high fidelity, despite the strongly inhomogeneous nature of the ensemble
approach. In this paper full control over the qubit Bloch sphere is demonstrated, by performing arbitrary
qubit rotations and characterizing the outcomes using quantum state tomography.
In photon-echo-based optical data storage and data processing the photon echo output intensity generally is about 0.1 - 1% of the input intensity. Many devices, such as processors would require that the photon echo output is used as an input to a new photon echo process. To obtain a sufficient signal-to- noise it would be necessary to first amplify the photon echo output signal. In this paper Pr-doped ZBLAN fibers are used to amplify the photon echo signals generated in Pr-doped Y2SiO5 at 606 nm. The fiber amplifier is pumped by the 476 nm output from an Ar-ion laser. Mirror-less lasing due to reflection at the fiber ends is eliminated by cleaving the fiber ends at an angle. The upper limit of the gain in a fiber is set by the core refractive index and the fiber numerical aperture. By changing from a fiber with numerical aperture of 0.4 to one with 0.15, the gain obtained at 606 nm is increased from 45 to 330.
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