Multi-wavelength fluorescence imaging with a da Vinci Firefly—a technical look behind the scenes

Abstract

The field of fluorescence-guided surgery builds on colored fluorescent tracers that have become available for different clinical applications. Combined use of complementary fluorescent emissions can allow visualization of different anatomical structures (e.g. tumor, lymphatics and nerves) in the same patient. With the aim to assess the requirements for multi-color fluorescence guidance under in vivo conditions, we thoroughly characterized two FDA-approved laparoscopic Firefly camera systems available on the da Vinci Si or da Vinci Xi surgical robot. In this process, we studied the cameras’ performance with respect to the photophysical properties of the FDA-approved dyes Fluorescein and ICG. Our findings indicate that multi-wavelength fluorescence imaging of Fluorescein and ICG is possible using clinical-grade fluorescence laparoscopes, but critical factors for success include the photophysical dye properties, imaging system performance and the amount of accumulated dye. When comparing the camera performance, the Xi system provided more effective excitation (adaptions in the light source) and higher detection sensitivity (chip-on-a-tip and/or enhanced image processing) for both Fluorescein and ICG. Both systems can readily be used for multi-wavelength fluorescence imaging of Fluorescein and ICG under clinically relevant conditions. With that, another step has been made towards the routine implementation of multi-wavelength image-guided surgery concepts.

How molecular imaging will enable robotic precision surgery

“…While most proof-of-concept studies have evaluated the use in microscopic neurosurgery (e.g., in glioblastoma [141]), there are also examples in laparoscopic surgery (e.g., parathyroid surgery [142], bladder cancer [143], liver cancer [144], and gynecology [145], or even robot-assisted laparoscopic surgery (i.e., prostate cancer [24])). Contrary to popular belief that only NIR-I (700-900 nm) is useful for fluorescence imaging, based on the relatively low tissueinduced absorption of light at these wavelengths, these studies do not visualize that much of a difference in intensity when used in a surgical environment, justifying the use of different wavelengths as well [146]. Even deeper NIR (e.g., 1000 to 1700 nm) has been suggested, theoretically providing higher resolution due to lower light scattering at these wavelengths [147].…”

The current status and future prospects for molecular imaging-guided precision surgery

“…This is a feature that may substantially increase utility, but also comes with increases in cost. While common practice, improvements in sensitivity do not necessarily result in an enlarged footprint, as they may also come from improved detector materials and refined signal processing [ 106 , 138 ].

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“…A key example is the visualization of (NIR) fluorescence signals in artificial colors to improve contrast: white [ 178 ], blue [ 179 ], pink [ 180 ], or as rainbow coloration [ 181 ] whereby green (color for which the human eye is most sensitive) has been most abundantly used. Alternatively, signal intensities can be boosted digitally, where again examples can be found in fluorescence imaging [ 106 ]. A more advanced version of computer visualization is automated feature extraction and data quantification.…”

Multispectral Imaging Using Fluorescent Properties of Indocyanine Green and Methylene Blue in Colorectal Surgery—Initial Experience

“…Recently, a publication presenting the first usage of multi-wavelength fluorescence imaging in colorectal surgery has showed the possibility of using a standard Firefly system to visualise lymphatic vessels with fluorescein and lymph nodes with ICG [29]. For similar visualisation of both fluorophores, they had to adjust fluorescein concentration.…”