Design and characterization of an optimized simultaneous color and near-infrared fluorescence rigid endoscopic imaging system

Abstract

Abstract. We report the design, characterization, and validation of an optimized simultaneous color and near-infrared (NIR) fluorescence rigid endoscopic imaging system for minimally invasive surgery. This system is optimized for illumination and collection of NIR wavelengths allowing the simultaneous acquisition of both color and NIR fluorescence at frame rates higher than 6.8 fps with high sensitivity. The system employs a custom 10-mm diameter rigid endoscope optimized for NIR transmission. A dual-channel light source compatible with the constraints of an endoscope was built and includes a plasma source for white light illumination and NIR laser diodes for fluorescence excitation. A prism-based 2-CCD camera was customized for simultaneous color and NIR detection with a highly efficient filtration scheme for fluorescence imaging of both 700-and 800-nm emission dyes. The performance characterization studies indicate that the endoscope can efficiently detect fluorescence signal from both indocyanine green and methylene blue in dimethyl sulfoxide at the concentrations of 100 to 185 nM depending on the background optical properties. Finally, we performed the validation of this imaging system in vivo during a minimally invasive procedure for thoracic sentinel lymph node mapping in a porcine model.

In vivo fluorescence imaging of hepatocellular carcinoma xenograft using near-infrared labeled epidermal growth factor receptor (EGFR) peptide

“…A footswitch was used to change the imaging mode between white light and fluorescence. Previously, a rigid 10 mm diameter endoscope has been developed for for minimally invasive surgery that simultaneously detects color and NIR fluorescence, and was used to image lymph nodes in live pigs using ICG for contrast [15]. Our compact imaging module is similar in weight (977 versus 726 grams), but has higher image resolution (1932 × 1452 versus 960 × 960) and faster speed (15 versus 6.8 frames/sec) to provide clearer images with less motion artifact.…”

Image overlay solution based on threshold detection for a compact near infrared fluorescence goggle system

“…The footprint for these devices is typically large, and the high cost associated with these systems limits the dissemination of the systems. Minimally invasive surgical procedures, such as endoscopy 14 and laparoscopy, [15][16][17] have also benefited from NIR fluorescence. Optimized NIR rigid probes have been used to simultaneously acquire fluorescence and visible spectrum information and to present this information on an overlaying monitor.…”

Real-time endoscopic optical properties imaging

“…2(a) has minimal components and can be relatively inexpensive depending on the choice of source, endoscope, and camera. The NIR source used in this system has been built and described in recent work [23]. For this embodiment, we utilized two 1W laser diodes operating at 660 nm (LDX-3115-660, LDX Optronics, Maryville, TN) along with current and thermoelectric cooler controllers (ITC300, Thorlabs, Newton, NJ).…”

“…Long acquisition times (fewer than 1 frame per second, fps) are prone to motion artifacts created by a moving sample and are unable to capture dynamics of motion or changing optical properties. Long acquisition times are also not suitable for endoscopy, which requires at least a rate of 10 fps for proper visualization [23]. SSOP uses spatial-frequency filtering to demodulate the optical reflectance signal from the projected carrier wave by utilizing the AC and DC components of a single sinusoidal projection.…”