Photon emission from perturbed and dying organisms: biomedical perspectives.

Living systems spontaneously emit ultraweak light (ultraweak photon emission, UPE) during the process of metabolic reactions associated with the normal physiological state. Stress factors and pathological states change parameters of that emission, such as intensity, yield, temporal, statistical and spectral characteristics. Thus, properties of UPE are inherently associated with and derived from biochemical and biophysical excitation processes. UPE can be considered as a holistic expression of the perturbation of the physiological state of the bio-system and may carry information on the bioenergetics, kinetics and character of biochemical and physiological processes, functioning of the regulatory feedback systems and the degree of perturbation by internal and external factors. This article presents an overview of the fundamentals of UPE and its relation to physiological processes.