Jesung Park

• Texas A&M University

MR-guided focal cryoablation of prostate cancer has often been selected as a minimally-invasive treatment option. Placing multiple cryo-needles accurately to form an ablation volume that adequately covers the target volume is crucial for better oncological/functional outcomes. This paper presents an MRI-compatible system combining a motorized tilti...

Noninvasive assessment of skin lesions, especially of basal cell carcinoma (BCC), has benefited more recently from the use of optical imaging techniques such as optical coherence tomography (OCT) and reflectance confocal microscopy (RCM). While RCM provides submicron scale resolution and thus enables identification of skin morphological changes of...

Background: Our objective was to develop and test a combined Raman microspectroscopy (RMS) and micro-optical coherence tomography (μOCT) approach for chairside quantification of gingival collagen, DNA, epithelium and connective tissue. We hypothesized that a high-resolution RMS/μOCT can characterize healthy and inflamed periodontal tissues for dia...

Purpose Magnetic resonance imaging (MRI)‐guided transperineal prostate biopsy has been practiced since the early 2000s. The technique often suffers from targeting error due to deviation of the needle as a result of physical interaction between the needle and inhomogeneous tissues. Existing needle guide devices, such as a grid template, do not allow...

Providing surgical margin information during breast cancer surgery is crucial for the success of the procedure. The margin is defined as the distance from the tumor to the cut surface of the resection specimen. The consensus among surgeons and radiation oncologists is that there should be no tumor left within 1 to maximum 2 mm from the surface of t...

Voice disorders affect a large number of adults in the United States, and their clinical evaluation heavily relies on laryngeal videostroboscopy, which captures the medial-lateral and anterior-posterior motion of the vocal folds using stroboscopic sampling. However, videostroboscopy does not provide direct visualization of the superior-inferior mov...

We report the development and the pre-clinical testing of a new technology based on optical coherence tomography (OCT) for investigating tissue composition at the tip of the core biopsy needle. While ultrasound, computed tomography, and magnetic resonance imaging are routinely used to guide needle placement within a tumor, they still do not provide...

We present a hand-held implementation and preliminary evaluation of a combined optical coherence tomography (OCT) and reflectance confocal microscopy (RCM) probe for detecting and delineating the margins of basal cell carcinomas (BCCs) in human skin in vivo. A standard OCT approach (spectrometer-based) with a central wavelength of 1310 nm and 0.11...

During clinical voice assessment, laryngologists and speech-language pathologists rely heavily on laryngeal endoscopy with videostroboscopy to evaluate pathology and dysfunction of the vocal folds. The cost effectiveness, ease of use, and synchronized audio and visual feedback provided by videostroboscopic assessment serve to maintain its predomina...

Multimodal imaging probes a variety of tissue properties in a single image acquisition by merging complimentary imaging technologies. Exploiting synergies amongst the data, algorithms can be developed that lead to better tissue characterization than could be accomplished by the constituent imaging modalities taken alone. The combination of optical...

We present a novel technology based on a high sensitivity/specificity cancer targeting agent and of a novel fluorescence-guided microscopy (FGM) scheme for intraoperative assessment of surgical margins in breast cancer patients. Cancer cells are targeted using an optically silent peptide substrate coupled to a near infrared (NIR) fluorochrome that...

We present a novel method, based on encoder mapping OCT imaging, for real-time guidance of core biopsy procedures. This method provides real-time feedback to the interventional radiologist, such that he/she can reorient the needle during the biopsy and sample the most representative area of the suspicious mass that is being investigated. This aspec...

It is known that the progression of oral cancer is accompanied by changes in both tissue biochemistry and morphology. A multimodal imaging approach combining functional and structural imaging modalities could therefore provide a more comprehensive prognosis of oral cancer. This idea forms the central theme of the current study, wherein this premise...

We report the development of a novel otoscopy probe for assessing middle ear anatomy and function. Video imaging and phase-sensitive optical coherence tomography are combined within the same optical path. A sound stimuli channel is incorporated as well to study middle ear function. Thus, besides visualizing the morphology of the middle ear, the vib...

We demonstrate a miniature, tunable, minimally invasive endoscope for diagnosis of the auditory system. The probe is designed to sharply image anatomical details of the middle ear without the need for physically adjusting the position of the distal end of the endoscope. This is achieved through the addition of an electrowetted, tunable, electronica...

Significance The membranes within the cochlea vibrate in response to sound. However, measuring these vibrations to study the sense of hearing has been a technological challenge because invasive techniques have been required. Herein, we describe a new technique capable of depth-resolved displacement measurements in 3D space with picometer sensitivit...

Aims: The aim of this study was to validate novel imaging technology for simultaneous morphological and biochemical endogenous optical imaging of coronary atherosclerotic plaque. Methods and results: Optical coherence tomography (OCT) generates high-resolution 3D images of plaque morphology and endogenous fluorescence lifetime imaging microscopy...

Optical coherence tomography (OCT) is a medical imaging technique that provides tomographic images at micron scales in three dimensions and high speeds. The addition of molecular contrast to the available morphological image holds great promise for extending OCT's impact in clinical practice and beyond. Fundamental limitations prevent OCT from dire...

Phase-sensitive Optical Coherence Tomography (PhOCT) is an emerging tool for in vivo investigation of the vibratory function of the intact middle and inner ear. PhOCT is able to resolve micron scale tissue morphology in three dimensions as well as measure picometer scale motion at each spatial position. Most PhOCT systems to date have relied upon t...

Phase-sensitive optical coherence tomography (PhOCT) offers exquisite sensitivity to mechanical vibration in biological tissues. There is growing interest in using PhOCT for imaging the nanometer scale vibrations of the ear in animal models of hearing disorders. Swept-source-based systems offer fast acquisition speeds, suppression of common mode no...

Most studies evaluating the potential of optical coherence tomography (OCT) for the diagnosis of oral cancer are based on visual assessment of OCT B-scans by trained experts. Human interpretation of the large pool of data acquired by modern high-speed OCT systems, however, can be cumbersome and extremely time consuming. Development of image analysi...

Optical coherence tomography (OCT) is a medical imaging technique that provides tomographic images at micron scales in three dimensions and high speeds. The addition of molecular contrast to the available morphological image holds great promise for extending OCT’s impact in clinical practice and beyond. Fundamental limitations prevent OCT from dire...

Simultaneous endogenous fluorescence lifetime imaging (FLIM) and optical coherence tomography (OCT) of a hamster cheek-pouch model of oral epithelial cancer allowed discriminating in-vivo benign and malignant lesions with sensitivity and specificity >90%.

Sound transduction within the auditory portion of the inner ear, the cochlea, is a complex nonlinear process. The study of cochlear mechanics in large rodents has provided important insights into cochlear function. However, technological and experimental limitations have restricted studies in mice due to their smaller cochlea. These challenges are...

Sound transduction within the auditory portion of the inner ear, the cochlea, is a complex nonlinear process. The study of cochlear mechanics in large rodents has provided important insights into cochlear function. However, technological and experimental limitations have restricted studies in mice due to their smaller cochlea. These challenges are...

We demonstrated that simultaneous optical coherence tomography and fluorescence lifetime imaging microscopy imaging allows the identification of most types of coronary atherosclerotic plaques based on their morphological/biochemical characterization.

Clinical diagnosis of cochlear dysfunction typically remains incomplete due to a lack of proper diagnostic methods. Medical imaging modalities can only detect gross changes in the cochlea, and non-invasive in vivo cochlear measurements are scarce. As a result, extensive efforts have been made to adapt optical coherence tomography (OCT) techniques t...

Several factors are spurring the development of hardware and software to accomplish high-speed processing for Optical Coherence Tomography (OCT). The two most prevalent architectures incorporate either an FPGA or a GPU. While GPUs have faster clock-speed the fact an FPGA can be pipelined makes a direct comparison based simply on system specificatio...

To investigate the potential of endogenous multispectral fluorescence lifetime imaging microscopy (FLIM) for biochemical characterization of human coronary atherosclerotic plaques. Endogenous multispectral FLIM imaging was performed on the lumen of 58 segments of postmortem human coronary artery. The fluorescence was separated into three emission b...

We present the results of an animal study aimed at determining the value of collecting both morphological and biochemical images for oral cancer diagnosis using a multimodal optical coherence tomography and fluorescence lifetime imaging system.

Early detection of cancer is key to reducing morbidity and mortality. Morphological and chemical biomarkers presage the transition from normal to cancerous tissue. We have developed a noninvasive imaging system incorporating optical coherence tomography (OCT) and fluorescence lifetime imaging microscopy (FLIM) into a single optical system for the f...

Most pathological conditions elicit changes in the tissue optical response that may be interrogated by one or more optical imaging modalities. Any single modality typically only furnishes an incomplete picture of the tissue optical response, hence an approach that integrates complementary optical imaging modalities is needed for a more comprehensiv...

Fluorescence lifetime imaging microscopy (FLIM) offers a noninvasive approach for characterizing the biochemical composition of biological tissue. In recent years, there has been an increasing interest in the application of multispectral FLIM for medical diagnosis. Central to the clinical translation of FLIM technology is the development of robust,...

Early detection of cancer is key to reducing morbidity and mortality. Morphological and chemical biomarkers presage the transition from normal to cancerous tissue. We have developed a noninvasive imaging system incorporating optical coherence tomography and fluorescence lifetime imaging to acquire both sets of biomarkers. Here we report early favor...

We have developed a multimodal optical system for simultaneous optical coherence tomography (OCT) and fluorescence lifetime imaging microscopy (FLIM) imaging, and demonstrate its capability for high-speed co-registered micro-anatomical and biochemical tissue imaging.

Skin cancer is the most common form of human cancer. Its early diagnosis and timely treatment is of paramount importance for dermatology and surgical oncology. In this study, we evaluate the use of reflectance and fluorescence confocal microscopy for detecting skin cancers in an in-vivo trial with B16F10 melanoma and SCCVII squamous cell carcinoma...

To investigate the benefit of using time-resolved, laser-induced fluorescence spectroscopy for diagnosing malignant and premalignant lesions of the oral cavity. The carcinogen 7,12-dimethylbenz[a]anthracene (DMBA) was applied to 1 cheek pouch of 19 hamsters. The contralateral pouch and the cheek pouches of 3 hamsters without DMBA exposure served as...

Complex polarization ratio (CPR) in materials with birefringence and biattenuance is shown as a logarithmic spiral in the complex plane. A multi-state Levenberg-Marquardt nonlinear fitting algorithm using the CPR trajectory collected by polarization sensitive optical coherence tomography (PS-OCT) was developed to determine polarization properties o...

We report a tissue diagnostic system which combines two complementary techniques of time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) and ultrasonic backscatter microscopy (UBM). TR-LIFS evaluates the biochemical composition of tissue, while UBM provides tissue microanatomy and enables localization of the region of diagnostic interest...

We demonstrate the feasibility of a time-resolved fluorescence spectroscopy (TRFS) technique for intraluminal investigation of arterial vessel composition under intravascular ultrasound (IVUS) guidance. A prototype 1.8-mm (5.4 Fr) catheter combining a side-viewing optical fiber (SVOF) and an IVUS catheter was constructed and tested with in vitro ve...

We report the development of a diagnostic system combining time-resolved fluorescence spectroscopy and ultrasound backscatter microscopy and its application in diagnosis of tumors and atherosclerotic disease. This system allows for concurrent evaluation of distinct compositional, functional, and micro-anatomical features of normal and diseased tiss...

We report the development and validate a multi-modal tissue diagnostic technology, which combines three complementary techniques into one system including ultrasound backscatter microscopy (UBM), photoacoustic imaging (PAI), and time-resolved laser-induced fluorescence spectroscopy (TR-LIFS). UBM enables the reconstruction of the tissue microanatom...

A novel fiber-optic-based method for simultaneous time- and wavelength-resolved fluorescence spectroscopy for the rapid diagnosis of diseased tissue is demonstrated. By combining multiple bandpass and dichroic filters (405/40, 460/50, and 550/50) with different lengths of optical fiber (1, 10, and 19 m ) acting as an optical delay this system enabl...

To compare the tensile strength of nylon, polypropylene, and fast-absorbing gut sutures treated with either 3% hydrogen peroxide or water for a period of 5 days to emulate a wound care regimen. An In-Spec 2200 bench-top tester was used to find the maximum load that a particular suture could sustain prior to breaking. Analysis of the data showed a s...

Incorporation of polarimetric sensitivity into optical coherence tomography can provide additional image contrast when structures of interest are optically anisotropic (e.g., fibrous tissue). We present a generalized technique based on polarization-sensitive optical coherence tomography to detect changes in depth-resolved fibre orientation and thus...

Trajectory of the normalized Stokes vector on the Poincaré sphere corresponding to light propagation in anisotropic tissues with birefringence and biattenuance is derived. Analytic expressions are determined from the Serret–Frenet formulas and derivatives of arc length for five quantities including the tangent, normal, and binormal vectors with cur...

Using enhanced polarization-sensitive optical coherence tomography (EPS-OCT), we demonstrate visualization and quantification of collagen fiber ultrastructure in cartilage. This is important for understanding the physiological and mechanical properties of cartilage and its associated diseases.

The purpose of this study was to measure the peripapillary retinal nerve fiber layer (RNFL) thickness, phase retardation (PR), and depth-resolved birefringence (Deltan) of the normal primate eye using Enhanced Polarization-Sensitivity Optical Coherence Tomography (EPS-OCT). Both eyes of two rhesus monkeys were imaged with EPS-OCT. A multiple incide...

Enhanced polarization-sensitive optical coherence tomography (EPS-OCT) is a noninvasive cross-sectional imaging technique capable of quantifying with high sensitivity the optically anisotropic properties of fibrous tissues. We present a method to measure the depth-resolved optic axis orientations in superficial and deep regions of multiple-layered...

Form-biattenuance (Δχ) in biological tissue arises from anisotropic light scattering by regularly oriented cylindrical fibers and results in a differential attenuation (diattenuation) of light amplitudes polarized parallel and perpendicular to the fiber axis (eigenpolarizations). Form-biattenuance is complimentary to form-birefringence (Δn) which r...

Polarization-sensitive optical coherence tomography provides high-resolution cross-sectional characterization of birefringence in turbid media. Weakly birefringent biological tissues such as the retinal nerve fiber layer (RNFL) require advanced speckle noise reduction for high-sensitivity measurement of form birefringence. We present a novel method...

Phase retardation per unit depth (PR/UD) is a physiologically significant parameter which correlates with the orderly arrangement of neurons and neurofibrils within the retinal nerve fiber layer (RNFL) and can vary in glaucoma. The objective of this study is to use Polarization Sensitive Optical Coherence Tomography (PSOCT), to detect both RNFL thi...

A nonlinear algorithm was developed to determine depth-resolved phase retardation. The robustness of the algorithm was verified using simulated polarization sensitive optical coherence tomography (PS-OCT) data on the Poincaré sphere.

Phase retardation per unit depth (PR/UD) is a physiologically significant parameter which correlates with the orderly arrangement of neurons and neurofibrils within the retinal nerve fiber layer (RNFL) and can vary in glaucoma. The objective of this study is to use Polarization Sensitive Optical Coherence Tomography (PSOCT), to detect both RNFL thi...

Polarization sensitive OCT has potential advantages in detecting diseases which affect the vitality of fibrous tissues. We present a nonlinear numerical algorithm to suppress speckle noise and enable accurate quantitative measurement of fibrous tissue properties.

We study blood flow effects on polarization sensitive optical coherence tomography images and birefringence measurement. Doppler shift and absorption from blood flow through a capillary tube surrounded by birefringent collagen films are recorded and analyzed.

This paper presents an algorithm to analyze phase retardation and measure the primate retinal nerve fiber layer (RNFL) thickness from retinal images recorded by polarization sensitive optical coherence tomography (PSOCT). Analysis of the phase retardation and the thickness of the RNFL begins with calculating the Stokes parameters from the horizonta...

Imaging the birefringence characteristics of the retinal nerve fiber layer (RNFL) may aid in glaucoma diagnosis. Polarization Sensitive Optical Coherence Tomography (PSOCT) was used to record in vivo high resolution images of the RNFL in two cynomologous monkeys. Depth variation in the Stokes vector of reflected light was used to calculate the opti...

Thesis (Ph. D.)--University of Texas at Austin, 2006. Includes bibliographical references. Vita. Requires PDF file reader.

Thesis (M.S. in Engineering)--University of Texas at Austin, 2003. Includes bibliographical references.