Ultraviolet germicidal irradiation of the inner bore of a CT gantry

Abstract

To investigate the feasibility and practicality of ultraviolet (UV) germicidal irradiation of the inner bore of a computed tomography (CT) gantry as a means of viral decontamination. Method: A UV lamp (PADNUT 38 W, 253 nm UV-C light tube) and UV-C dosimeter (GENERAL UV-C Digital Light Meter No. UV512C) were used to measure irradiance throughout the inner bore of a CT scanner gantry. Irradiance (units μW/cm 2) was related to the time required to achieve 6-log viral kill (10 −6 survival fraction). Results: A warm-up time of~120 s was required for the lamp to reach stable irradiance. Irradiance at the scan plane (z = 0 cm) of the CT scanner was 580.9 μW/cm 2 , reducing to~350 μW/cm 2 at z = AE20 cm toward the front or back of the gantry. The angular distribution of irradiation was uniform within 10% coefficient of variation. A conservative estimate suggests at least 6-log kill (survival fraction ≤ 10 −6) of viral RNA within AE20 cm of the scan plane with an irradiation time of 120 s from cold start. More conservatively, running the lamp for 180 s (3 min) or 300 s (5 min) from cold start is estimated to yield survival fraction <<10 −7 survival fraction within AE20 cm of the scan plane. Conclusion: Ultraviolet irradiation of the inner bore of the CT gantry can be achieved with a simple UV-C lamp attached to the CT couch. Such practice could augment manual wipe-down procedures, improve safety for CT technologists or housekeeping staff, and could potentially reduce turnover time between scanning sessions.

Magnetic Resonance Imaging During a Pandemic: Recommendations by the ISMRM Safety Committee

“…Ultraviolet‐C (UV‐C) light energy is an effective technology to clean surfaces 13,14 . Systems utilizing UV‐C technology have been shown to be effective and efficient for sterilizing computed tomography (CT) scanner equipment 15 . Several UV‐C light energy systems are MR compatible and have been optimized for sterilization of the MR scanner bore in as little as 2–3 minutes.…”