Practical approach to prevent COVID-19 infection at breast cancer screening

Abstract

Background The novel coronavirus disease 2019 (COVID-19) undermines the benefits of cancer screening. To date, no study has identified specific infection control methods. We aimed to provide practical methods for COVID-19 risk reduction during breast cancer screening mammography (MMG) by examining an overview of potential contamination routes of aerosols and possible risks for patients and health care providers. Methods Computational fluid dynamics (CFD) simulations were conducted for airflow and aerosol dispersion in a 3D virtual model of a mobile MMG laboratory room. This model was constructed based on the actual mobile screening MMG bus ‘Cosmos’ in the Chiba Foundation for Health Promotion & Disease Prevention. Examiner and patient geometries were obtained by scanning an actual human using a 3D Scanner. Contamination of the room was evaluated by counting the numbers of suspended and deposited aerosols. Results We applied the CFD simulation model to the exhalation of small or large aerosols from a patient and examiner in the MMG laboratory. Only 14.5% and 54.5% of large and small aerosols, respectively, were discharged out of the room with two doors open. In contrast, the proportion of large and small aerosols discharged out of the room increased to 96.6% and 97.9%, respectively, with the addition of forced gentle wind by the blower fan. This simulation was verified by a mist aerosol experiment conducted in the mobile MMG laboratory. Conclusion Adding forced ventilation to a MMG laboratory with two doors open may enable risk reduction dramatically. This could be applied to other clinical situations.

Infection control for COVID-19 in hospital examination room

“…1 ). This finding is consistent with our previous report 9 . Furthermore, the movement of aerosols was modeled under the assumption that a patient coughs, and it was found that the number of aerosols deposited on the physician was comparable with that resulting from normal patient expiration, although small aerosols diffused widely throughout the room (Fig.…”

“…To investigate how to efficiently ventilate indoor spaces, it is important to understand air flow as a function of humidity, which has a strong effect on aerosol properties. We have previously investigated and reported infection control methods in medical settings 9 .…”

Infection control for COVID-19 in hospital examination room

“…The results of this theoretical study clearly show that aerosols emitted from a patient's mouth or nose in an examination room, where masks must be removed, are greatly affected by the airflow in the room, and the risk of their deposition on the physician and elsewhere in the room cannot be neglected (Figure 2). This finding is consistent with our previous report (8). Furthermore, the movement of aerosols was modeled under the assumption that a patient coughs, and it was found that the number of aerosols deposited on the physician was comparable with that resulting from normal patient expiration, although small aerosols diffused widely throughout the room (Figure 3).…”

“…We have previously investigated and reported infection control methods in medical settings. (8) Indoor healthcare facilities attract both infected people and patients at high risk of serious illness. Various evidence shows that strict precautions against droplet exposure, such as wearing personal protective equipment and social distancing, are insufficient, and measures to prevent exposure to aerosols are not always well considered.…”

Optimization of Suction Device Installation for Control of Aerosol Dispersion in Otorhinolaryngology Examination Rooms

“…In addition, previous studies have investigated aerosol removal by forced ventilation [7] and air-conditioning systems that control aerosol behavior [8] in consultation rooms. However, it may be difficult to replicate these methods in existing consultation rooms.…”