Medical Applications of Space Light-Emitting Diode Technology- Space Station and Beyond

Abstract. Space light-emitting diode (LED) technology has provided medicine with a new tool capable of delivering light deep into tissues of the body, at wavelengths which are biologically optimal for cancer treatment and wound healing. This LED technology has already flown on Space Shuttle missions. and shows promise for wound healing applications of benefit to Space Station astronauts. PHOTODYNAMIC THERAPY Photodynamic therapy (PDT) is a cancer treatment modality that recently has been applied as adjuvant therapy for brain tumors. PDT consists of intravenously injecting a photosensitizer, which preferentially accumulates in tumor cells, into a patient and then activating the photosensitizer with a light source. This results in free radical generation followed by cell death. The development of more effective light sources for PDT of brain tumors has been facilitated by applications of space light-emitting diode array technology; thus permitting deeper tumor penetration of light and use of better photosensitizers. Lutetium Texaphyrin (Lutex) is a new, second generation photosensitizer that can potentially improve PDT for brain tumors. Lutex has a major absorption peak at 730 nm, which gives it two distinct advantages. First, longer wavelengths of light penetrate brain tissue easily so that larger tumors could be treated, and second, the major absorption peak means that more of the drug is activated upon exposure to light. Tumoricidal effects of Lutex have been studied in vitro using canine glioma and human glioblastoma cell cultures