Fluorescence/characterization

= Introduction =

Fluorescence occurs when a substance emits light after having absorbed it from another source. It is characterized as a form of luminescence.

Essentially, luminescence is the emittance of light by a substance or body without the use of heat – 'cold body radiation'. When electrons of a body's molecules are excited, they transition from a ground state to an excited state, soon after relaxing to the lowest possible excited energy state, and transitioning back to the ground state. This plethora of energy shifts of the electrons produces light. The process of electron excitation can occur due to a number of different phenomena. Fluorescence in particular is a type of photoluminescence, which happens once a substance absorbs photons, or light particles, that hold enough energy to cause a change in the electrons of a molecule.

= Use in Clinical Medicine =

Fluorescence has significant use in medicine, particularly as a diagnostic and research tool – this is largely due to the accuracy of identification of fluorescence, as well as lack of associated risk and ease of use. It is also recognized for its advantages when the phenomena is applied in internal tracers, due to the relative safety from internal damage or poisoning of the patient. A number of organic (carbon-containing) material can produce fluorescence and be well detectable should it undergo radiation from a light source of a correct wavelength, which is useful in identifying certain structures or abnormalities within the body of the patient.

White blood cells produce fluorescence as well, which means that identification or discrimination of malfunctional cells, as well as differentiation of leukocyte families is possible as a research tool.