We have developed a compact optical endoscopic probe for in vivo fluorescence optical imaging device. We obtained fluorescence image for the colon tissue of a mouse using a compacted optical endoscopic probe with a designed endoscopic optical lens. In order to demonstrate endoscopic fluorescence imaging for the colon cancer, we have manufactured a compacted optical endoscopic probe to pass through the biopsy channel of electric flexible endoscope. The compacted optical endoscopic probe with maximum outside diameter of 2.8mm consists of fiber-optic illumination part and imaging part. The imaging part consists of a fiber-optic imaging bundle linked to an endoscopic optical lens and focus assembly. We considered a compact structure, sensitivity, and FOV for the design of the endoscopic optical lens. We have suggested an endoscopic optical lens with an FOV of 90 ° and DOF of 3 – 80mm. The optical system consists of glass-based aspheric lenses. The total track is less than 2.5 mm, and the diameter is limited to less than 1.5 mm to obtain a compact system. We have presented the compacted optical endoscopic probe for cancer imaging of a mouse. The proposed endoscopic optical lens showed sufficient sensitivity and a wide field of view for obtaining fluorescence imaging. We demonstrated endoscopic ex vivo fluorescence imaging for the colon cancer of a mouse using the compacted optical endoscopic probe.
We have designed a fiber probe based optical diagnose system for detection of interspecies transmissibility. We have showed the optical performance to measure the optical signal of the target sample by using the manufactured fiber probe. We have confirmed the capability of our system to be utilized to biomedical diagnose applications.
We previously reported the potential of using vascular reactivity during respiratory challenges as a marker to predict the response of breast tumor to chemotherapy in a rat model by using a continuous wave near-infrared spectroscopy. However, it cannot visualize how the vascular reactivity from tumor vessel can predict the tumor response to its treatment. In this study, we utilized a spectral domain optical coherence tomography (SD-OCT) system to visualize vascular reactivity of both tumor and normal vasculature during respiratory challenges in a mouse model. We adapted intensity based Doppler variance algorithm to draw angiogram from the ear of mouse (8-week-old Balb/c nu/nu). Animals were anesthetized using 1.5% isoflurane, and the body temperature was maintained by a heating pad. Inhalational gas was switched from air (10min) to 100% oxygen (10min), and a pulse oximeter was used to monitor arterial oxygen saturation and heart rate. OCT angiograms were acquired 5 min after the onset of each gas. The vasoconstriction effect of hyperoxic gas on vasculature was shown by subtracting an en-face image acquired during 100% oxygen from the image acquired during air inhalation. The quantitative change in the vessel diameter was measured from the en-face OCT images of the individual blood vessels. The percentage of blood vessel diameter reduction varied from 1% to 12% depending on arterial, capillary, or venous blood vessel. The vascular reactivity change during breast tumor progression and post chemotherapy will be monitored by OCT angiography.
Optical-resolution photoacoustic microscopy (OR-PAM) has been studied to improve its imaging resolution and functional imaging modality without labeling on biology sample. However the use of high numerical aperture (NA) objective lens confines the field of view or the axial imaging range of OR-PAM. In order to obtain images at different layers, one needs to change either the sample position or the focusing position by mechanical scanning. This mechanical movement of the sample or the objective lens limits the scanning speed and the positioning precision. In this study, we propose a multi-depth PAM with a focus tunable lens. We electrically adjusted the focal length in the depth direction of the sample, and twice extended the axial imaging range up to 660 μm with the objective lens (20X, NA 0.4). The proposed approach can increase scanning speed and avoid step motor induced distortions during PA signal acquisitions without mechanical scanning in the depth direction. To investigate the performance of the multi-depth PAM system, we scanned a black human hair and the ear of a living nude mouse (BALB/c Nude). The obtained PAM images presented the volumetric rendering of black hair and the vasculature of the nude mouse.