In the 3D model, viability and other parameters of both irradiated and non-irradiated tissues can be determined using MTT assay, cytokine release, histological examination, RNA abundance measurements, etc. (MatTek Corporation In Vitro 3-D Model Basics; Limardi et al. (1996) J Invest Dermatol 106(4):939, Abstract #803; and Last et al. (2002) Society of Investigative Dermatology Meeting).The test pe