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Several fluorescent agents have been approved for fluorescence based diagnosis & intraoperative imaging: Dye generic name Countries Excitation Detection Indications Indocyanine Green (ICG) Worldwide 800 nm Near-infrared (820 nm) Multiple uses: lymphatic mapping, tissue perfusion, visualization of biliary ducts and blood veins, retinal angiography Fluorescein Worldwide 490 nm Green fluorescence (525 nm) Fluorescein angiography or angioscopy (ophthalmology) Methylene Blue Worldwide 665 nm 688 nm Endoscopic polypectomy, chromoendoscopy, lymphatic drainage 5-ALA Hydrochloride (converted to Pp-IX) Worldwide 400 – 410 nm Red fluorescence (620 – 710 nm) Continue reading →Introduction to fluorescence imaging Fluorescence is a phenomenon where substance that has absorbed certain wavelength of light emits it back at another wavelength. These substances are called fluorophores or fluorescent dyes. The emitted light has a longer wavelength than the absorbed one since some energy of the photon is lost in the process. The difference in wavelengths between absorbed and emitted light, called Stokes shift, allows very low background for fluorescence detection by separating it from the excitation light. The process of fluorescence generation is Continue reading →