Red radioluminescence and radiochemiluminescence: premises for a photodynamic tumour therapy with X-rays and haematoporphyrin derivatives. A working hypothesis.

In a 1989 paper the author put forward the hypothesis of homogeneously illuminating the interior of the human body with red light by means of X-rays, with a view to extending the possibilities of photodynamic therapy with haematoporphyrin derivatives (HPD). In the present paper, two possible mechanisms for the production of red light by tissues irradiated with X-rays are put forward: a physical mechanism (red radioluminescence) and a physical-chemical mechanism (red radiochemiluminescence). Reactive oxygen metabolites produced in the radiolysis of water, singlet oxygen and lipid peroxidation of biomembranes are the key players in this interesting process. However, before any clinical application can be proposed for integrated tumour therapy (photodynamic therapy with X-rays instead of laser light and haematoporphyrin derivatives), quantitative analyses and experimental research will be required.