We demonstrate the use of phase-stabilized swept-source optical coherence tomography to assess the propagation of low-amplitude (micron-level) waves induced by a focused air-pulse system in tissue-mimicking phantoms, a contact lens, a silicone eye model, and the mouse cornea in vivo. The results show that the wave velocity can be quantified from the analysis of wave propagation, thereby enabling the estimation of the sample elasticity using the model of surface wave propagation for the tissue-mimicking phantoms. This noninvasive, noncontact measurement technique involves low-force methods of tissue excitation that can be potentially used to assess the biomechanical properties of ocular and other ...

Kirill Larin, Ph.D.

Associate Professor

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We present a three-dimensional (3-D) computational method to detect soft tissue sarcomas with the goal of automatic surgical margin assessment based on optical coherence tomography (OCT) images. Three parameters are investigated and quantified from OCT images as the indicators for the tissue diagnosis including the signal attenuation (A-line slope), the standard deviation of the signal fluctuations (speckles), and the exponential decay coefficient of its spatial frequency spectrum. The detection of soft tissue sarcomas relies on the combination of these three parameters, which are related to the optical attenuation characteristics and the structural features of the tissue. Pilot experiments were performed ...

Accurate non-invasive assessment of tissue elasticity in vivo is required for early diagnostics of many tissue abnormalities. We have developed a focused air-pulse system that produces a low-pressure and short-duration air stream, which can be used to excite transient surface waves (SWs) in soft tissues. System characteristics were studied using a high-resolution analog pressure transducer to describe the excitation pressure. Results indicate that the excitation pressure provided by the air-pulse system can be easily controlled by the air source pressure, the angle of delivery, and the distance between the tissue surface and the port of the air-pulse system. Furthermore, we ...

Fingerprint biometrics, including automated fingerprint identification systems (AFIS), currently occupy two-thirds of the biometric market and are expected to remain the dominant player in this area. The technology can be integrated into small, compact devices and the instruments are relatively fast. However, the overall success of using fingerprints for identification and verification purposes greatly depends upon the quality of the fingerprints initially enrolled. For example, fingerprints captured from older people are significantly lower quality than those from younger people due primarily to ridge-wearing and difficulty of interacting effectively with conventional fingerprint scanners. The ramification is that the problem of obtaining ...

We propose the use of correlation mapping optical coherence tomography (cmOCT) to deliver additional biometrics associated with the finger that could complement existing fingerprint technology for law enforcement applications. The current study extends the existing fingerprint paradigm by measuring additional biometrics associated with sub-surface finger tissue such as sub-surface fingerprints, sweat glands, and the pattern of the capillary bed to yield a user-friendly cost effective and anti-spoof multi-mode biometric solution associated with the finger. To our knowledge no other method has been able to capture sub-surface fingerprint, papillary pattern and horizontal vessel pattern in a single scan or to show ...

Optical coherence tomography combined with a focused air-puff system non-invasively assesses the mechanical properties of soft tissues and can be used to differentiate tumors during surgical treatment. Surgical resection is currently the most effective treatment for patients with soft-tissue tumors, which develop within connective tissues such as muscle and fat. To minimize the removal region and reduce the chance of recurrence, it is important to delineate the boundaries of the tumor prior to resection. As tumorigenesis involves a change in tissue stiffness, probing the mechanical properties (e.g. elasticity) of soft tissues could complement structural imaging (x-ray and magnetic resonance ...