Journal of Surgery and Interventional Radiology

Fluorescence image-guided surgery (FIGS)

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Fluorescence image-guided surgery is an advanced medical imaging technique that enhances surgical precision by utilizing fluorescently labeled structures to provide real-time visualization during procedures. This approach integrates fluorescence imaging into the surgical workflow, offering superior resolution and the ability to detect specific molecules compared to traditional imaging modalities. However, its effectiveness can be limited by penetration depth, which is typically around 100 micrometers in the visible spectrum but can extend up to 1–2 centimeters when employing near-infrared (NIR) excitation wavelengths. ?

The FIGS system comprises several key components: excitation sources, detection techniques, and imaging devices. Excitation sources, such as halogen lamps, light-emitting diodes (LEDs), and laser diodes, illuminate the surgical area to excite the fluorescent agents. Halogen lamps offer high power across a broad spectrum, while LEDs provide cost-effective, narrow-band excitation without the need for additional filters. Laser diodes deliver high-intensity light over specific wavelengths but require careful handling due to laser safety considerations. ?

Detection techniques involve capturing emitted fluorescence using optical filters, lenses, and digital cameras like charge-coupled devices (CCDs) or complementary metal-oxide-semiconductor (CMOS) sensors. These components work together to produce live images that overlay fluorescence data onto the surgical field, enhancing the surgeon's ability to identify and delineate critical structures. Real-time video processing can further improve contrast and signal-to-background ratios, facilitating more accurate interventions. ?

Clinically, FIGS has been employed across various surgical disciplines. In oncology, it aids in the precise resection of tumors by highlighting malignant tissues that have been labeled with fluorescent markers. For instance, indocyanine green (ICG) is a near-infrared fluorophore commonly used to visualize lymphatic pathways and sentinel lymph nodes, achieving high detection rates and sensitivity compared to conventional methods. Additionally, pafolacianine, marketed as Cytalux, is an optical imaging agent that binds to folate receptor-expressing cells, assisting in the identification of cancerous tissues during surgery. ?

The integration of FIGS into surgical practice offers numerous advantages, including enhanced delineation of anatomical structures, improved identification of pathological tissues, and the potential for more complete resections with minimal impact on surrounding healthy tissues. These benefits contribute to reduced recurrence rates and improved patient outcomes. However, challenges such as limited tissue penetration of fluorescent light and the need for specialized equipment and training must be addressed to optimize the efficacy and accessibility of FIGS.