Although many of our research interests are multi-modal, including MRI, SPECT, and PET, our primary focus is near-infrared fluorescence imaging and its clinical applications. Near-infrared light is invisible to the human eye but is capable of penetrating relatively deeply into living tissue. Our BENMD Program took the lead in imaging system development and invented multispectral and multiscale near-infrared fluorescence imaging systems that permit anatomy and function to be visualized simultaneously in real-time, with high sensitivity and no moving parts. These systems provide complete image guidance to surgeons during tumor resection and other surgeries in which a tissue target must be detected, assessed, or resected.
1. NIR-I imaging system (K-FLARE)
The K-FLARE and FIAT-L imaging systems are investigational NIR-I imaging devices allowing simultaneous real-time fluorescence (700 nm and 800 nm) and color imaging (400-650 nm) using laser light (Class 3R) and a dual channel CCD camera. The imaging system kit is not intended for human use, but for non-diagnostic, non-therapeutic, laboratory research use only.
The technical specifications include: 1) Dual separate NIR wavelengths with color overlay, 2) output sources with distinct wavelengths at 660 nm and 760 nm, 3) amendable fluence rate, > 1 mW/cm² at 660 nm and >3 mW/cm² at 760 nm within 13” working distances, 4) white light: 5780lux at 1/2” or 3600lux at 1/4”, 5) field of view: 5”x5”.
The software allows for two main operation modes: data acquisition/visualization and quantification. Each operating mode and all capabilities will be detailed in the following pages, but some key features include: Live streaming of up to three (3) independent channels, 2) up to 30fps per channel, 3) video streaming in 512x512 pixels or 960x960 pixels, 4) snapshot and video saving of 512x512 pixels, 5) saving video up to 4000 frames, 6) ROI tools for quantification such as (ellipse, rectangle, free form and line profile) with easy manipulation (translation, rotation, resizing, mirroring on both channels), 7) export quantification results to a comma separated text file for easy import, and 8) re-encoding of still images and videos to publication appropriate formats (.jpg and .mpeg).
2. Mesoscale imaging and NIR-II imaging
The Mesoscale Imaging System (MIS) allows real-time concurrent color imaging and two independent NIR florescence imaging channels. MIS system consist of three main modules: Illuminations and excitation, detection and filtration, and data acquisition and processing. The optical specifications are as follows: White light imaging is performed using an LMI-6000 (Dolan-Jenner, Boxborough, MA) LED Fiber Optic Illuminator (400-650 nm), which delivers light through fibers which split the white light into 4 fibers to uniformly illuminate the sample. Two custom assembled NIR diode lasers (Arroyo Instrumentation, San Luis Obispo, CA) with 660 nm and 760 nm wavelengths are used as excitation sources. The output power on the sample is between 2 and 8 mW/cm2 depending on excitation wavelength and working distance. For macroscale imaging, a macro zoom lens, 0-10X (Navitar Zoom 7010, Navitar Inc., Rochester, New York) allows close-up imaging without extension tubes or close-up lenses and the 0-10X magnification allows for imaging of the sample at various fields of view and magnifications at 2”-15” working distance. For microscale imaging, a Zoom6000 UltraZoom lens (Navitar Inc.) with Mitutoyo Plan Apo NIR Infinity Corrected Objective, 10X and 028 NA are used to magnify the ROI up to 10 µm. More details on MIS and NIR-II imaging systems will be published soon.
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- Yang AW, Cho SU, Jeong MY, Choi HS. NIR fluorescence imaging systems with optical packaging technology. J Microelectron Packag Soc. 2014;21(4):25-31.
- Kim TH, O’Brien C, Choi HS, Jeong MY. Fluorescence molecular imaging systems for intraoperative image-guided surgery. Appl Spectrosc Rev. 2018;53:349-59.
- Sajedi S, Sabet H, Choi HS. Intraoperative biophotonic imaging systems for image-guided interventions. Nanophotonics. 2019;8(1):99-116. PMCID: PMC6559750.
- Choi HS, Kim HK. Multispectral image-guided surgery in patients. Nat Biomed Eng. 2020;4:245.
Leader: Marc-André Tétrault, Ph.D.