Fluorescence Digital Imageing

Fluorescein Angiography(FFA):

angiography is the definition of a vessel or structure using a contrast medium. Contrast Medium (sodium fluorescein dye)is injected into a vein in the patients arms and timed photographs are taken using a fundus or SLO system.Fluorescein angiography is an important ophthalmic diagnostic test used to examine the blood vessels and associated structure of retina.It is used to diagnose sight threatening ophthalmic conditions and to locate areas that require treatment.

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Images above are examples of right and left eye fluorescence Angiograms.1: 45 sec. 2: 1min.20sec.These are Angiograms of the ocular fundus.

The Ocular fundus is the inner lining of the eye made up of the retina and choroid.This angiograms shows the optic nerve,the retina vessels and the macular.it shows the optic nerve through which visual signals are transmitted to the brain and the retinal vessels which supply nutrotion and oxygen to the tissue set against the red-orange colour of the pigment epithelium,which also makes up the fundus.

The word Angiography comes from the Greek angeion, "vessel" and graphien, "to write or record". Angiography is the imaging of vessels, and the resulting pictures are angiograms. Angiography of the retina of the eye requires the injection of a small amount of dye into a vein in the patient's arm. The dye travels through the blood stream and is photographed using special cameras and colors of light as it travels through the vessels of retina.

Fluorescein Angiography is performed with a dye called Sodium Fluorescein. When illuminated with a blue light, the fluorescein dye glows or fluoresces in yellow-green. Special filters in the camera allow only the fluorescent yellow-green light to be photographed, producing high contrast images of the retinal vessels. Fluorescein angiography can be performed using either standard black and white photographic film or using digital cameras.The first time i did FFA I was absolutely amazed that how fast the dye circulates around the body. 5 to 8 seconds after the fluorescein has been injected I could start taking the photographs.

Indocyanine Green (ICG) dye is used in conjunction with infrared "light" for angiography in very special cases where fluorescein angiography proves inadequate. Because infrared energy is not in the visible spectrum and can not be imaged well with photographic film, high-sensitivity digital cameras are used for ICG angiography.

http://micro.magnet.fsu.edu/primer/techniques/fluorescence/gallery/cells/index.htmlhttp://www.opsweb.org/OpPhoto/Angio/index.html