Dunn Emily F, Akhtar Adil, Dunn Adam, Lacey Scott, Pauley Ethan, Powers Colton, McKee James, Petereit Daniel
Department of Radiation Oncology, Willamette Valley Cancer Institute and Research Center, Eugene, Oregon.
Eugene, Oregon.
Adv Radiat Oncol. 2021 Mar-Apr;6(2):100636. doi: 10.1016/j.adro.2020.100636. Epub 2020 Dec 1.
The supply of N95 masks and filtering facepiece respirators (FFRs) has been limited nationally owing to the coronavirus disease 2019 pandemic. Ultraviolet C (UVC) light has been suggested as a potential option for decontamination of FFRs by the Centers for Disease Control. There has been a lack of publications characterizing UVC dose distribution across FFRs.
A UVC light box and FFR rack system was assembled using low-pressure mercury lamps peaked at 254 nm and aluminum flashing to reduce shadowing effect. Dose was characterized with the use of ultraviolet (UV) intensity labels and an ultraviolet germicidal irradiation (UVGI) National Institute of Standards and Technology traceable meter. Ozone production was evaluated after extended bulb run time.
Calibration of UV intensity labels was noted to have color-change saturation at 100 mJ/cm. Dose measurements with the UV intensity labels on the FFR demonstrated symmetrical dose to all surfaces, but symmetry was not supported by measurements with the UVGI meter. There was substantial dose fall off on the lateral aspects of the FFR. No ozone production was noted in the UVC system.
UV intensity labels for characterization of dose provided a false suggestion of symmetry compared with the UVGI meter. Estimates of appropriate exposure times to reach 1000 mJ/cm should be significantly increased to account for geometry of FFR and lateral dose fall off.
由于2019年冠状病毒病大流行，全国范围内N95口罩和过滤式面罩呼吸器（FFR）的供应受到限制。美国疾病控制中心建议，紫外线C（UVC）光可作为FFR消毒的一种潜在选择。目前缺乏关于UVC剂量在FFR上分布特征的出版物。
使用峰值波长为254nm的低压汞灯和铝箔组装了一个UVC灯箱和FFR架系统，以减少阴影效应。使用紫外线（UV）强度标签和一台可溯源至美国国家标准与技术研究院的紫外线杀菌辐照（UVGI）仪对剂量进行表征。在延长灯泡运行时间后评估臭氧生成情况。
注意到UV强度标签在100mJ/cm²处出现颜色变化饱和。在FFR上使用UV强度标签进行的剂量测量表明，所有表面的剂量对称，但UVGI仪的测量结果并不支持这种对称性。FFR侧面的剂量大幅下降。在UVC系统中未发现臭氧生成。
与UVGI仪相比，用于表征剂量的UV强度标签给出了错误的对称提示。考虑到FFR的几何形状和侧面剂量下降，应显著增加达到1000mJ/cm²所需的适当暴露时间估计值。
