Evaluation of a Stereotactic (6-direction) Ultraviolet Irradiating Pass Box

「ABSTRACT」Ultraviolet (UV) irradiation is a simple, effective, and widely accepted method for disinfection against microorganisms. We have developed a stereotactic pass box that has UV lamps installed for irradiation from 6 directions and evaluated its efficacy with physical and biological methods. We evaluated inactivation profiles for bacteria, fungi, and viruses. UV irradiation was performed for 5, 10, 15, and 20 seconds for bacteria and T4 bacteriophages and for 5, 10, 20, and 30 minutes for the human immunodeficiency virus and fungi. The biological efficiency of irradiation was measured on the basis of the reduction of infectivity. Bacteria and T4 bacteriophages were highly susceptible to UV, but the human immunodeficiency virus and fungi were less sensitive to UV and required more energy for inactivation. We also evaluated the efficacy of irradiation in proportion to the number of irradiation sources and observed a strong correlation with the UV radiant energy at each point. Six-directional (3-dimensional) UV irradiation was effective for sterilizing microorganisms at all positions tested in the irradiation area. We have evolved the new dimensions of the pass box, which is convenient, efficient, and reliable for decontamination.