Research Interests

Current Topics of Study

  • Near Infrared Spectroscopy


  • NIRS, first introduced by Jobsis, assessess oxy- and deoxyhemoglobin concetrations based on absoprtion spectrum of hemoglobin molexulres or track the neural activation based on scattering changes. In recent years, neuroimaging based on NIRS has been succesfully applied to clinical and physiological studies mostly on human brain. Because NIRS is noninvasive and applicable to a freely moving condition. NIRS has a strong potential as a functional brain monitoring system in clinical or cognitive neuroscience research. The main assumption of applying NIRS to functional study of the brain is that the oxygen demands in the region of neural activation facilitate the oxygen supply by triggering vasodilation, resulting in an increase in oxyhemoglobin and decrease in deoxyhemoglobin called neurovascular coupling. Nowadays, analysis of cerebral hemodynamic responses to epilepsy, estiomation of causal connectivity between cortical areas, NIRS based brain-machine interface (BMI), glio- and neurovascular coupling stuy for neurological diseases are performed by optical techniques.


  • Optical Coherence Tomography


  • Optical coherence tomography (OCT) is an optical imaging modality that can provide non-invasively refelctivity based cross-sectional images of microstructure within biological tissues. Polarization-sensitive OCT (PS-OCT), a functionally extended version of OCT, provides not only cross-sectional images but also additonally useful information, such as phase retardation and fast axis orienation, and degree of polarization resulted from polarization property chnages of light reflection from biolocial tissues. A number of medical applications using PS-OCT have been introduced: thermal damage, wound healing, and photo-aging assessment in skin, caries detection in dentistry, investigation of retinal nerve fiber layer and cornea in ophtamology, diagnosis of cervical dysplasia, etc. Nowadays, wound healing, quantification of scattering changes, diagnosis of cervical dysplasia studies, and studies in dermatology are performed by OCT techniques.


  • Intraoperative Fluorescence Imaging


  • Intraoperative Fluorescence Imaging is used for minimal resection cancer surgery or other surgical purposes. We can detect tumors by using Indo Cyanine Green(ICG), due to Enhanced Permeability and Retention (EPR) effect. Which means, ICG molecules aggregate on tumors. When Near InfraRed(NIR) lights were shoot on ICG, fluorescence was emitted. So surgeon can detect and remove tumors easily and properly. In these reasons, worldwide research groups study intraoperative fluorescence imaging. Currently, we interest in develop surgeon-friendly fluorescence Imaging glass system using Augmented Reality(AR) and machine vision studies. Surgeon can see overlaid fluorescence image on the real view and detect tumors directly. We expect this system to be more surgeon-friendly and accurate.



  • Two Photon Microscopy


  • Two-photon microscopy offers two advantages over other live cell imaging techniques: It penetrates up to 1 mm into tissue and it minimizes phototoxicity because the beam excites just a single focal point at a time. In order to excite a fluorophore labeling the tissue, two long-wavelength, low-energy photons must meet nearly simultaneously, combining their energy to create a quantum excitation event. The probability that such an event will occur is extremely low, but increases quadratically with laser intensity; a special laser is thus main element of the technology.