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Paragraph: The semicontaminated area includes the fever-CT control room,
fever-DR control room, and other patient examination access areas. The buffer zone includes
access areas for medical personnel and a dressing area for technologists. The clean area
includes the administrative office and the diagnostic room. The contaminated area was isolated from other areas using physical barricades. Directional signs were newly installed to guide patients and staff. Personal protection and training of staff
For providing care for patients with confirmed and suspected COVID-19, all hospital staff
are required to wear complete personal protective equipment [7]: medical protective clothing,
surgical cap, N95 mask, gloves, face shields, and goggles. Wearing and removing of the
equipment must be performed in accordance with the procedures and under the supervision of
the infection control nurse. Because staff members working in the contaminated area are under much situational
pressure, periodically taking time off could lower their physical and mental stress levels. The
technologists on fever-CT duty shifts are provided a break once a week for four hours. In
addition, the health of staff in the contaminated area must be monitored closely for the
symptoms of COVID-19. Pregnant staff must be assigned to the clean area. 7
The EMICT formulates and continually updates guidelines and educates all staff for West
China Hospital of Sichuan University. The EMICT training for staff is mainly involves
documents regarding infection control and CT findings of COVID-19 and maintains an EMICT
WeChat group for West China Hospital of Sichuan University. WeChat is the most widely used
social media app in China. The EMICT releases the latest national and hospital-based
information regarding COVID-19, guidance documents, and other notices from the hospital
and radiology department in the WeChat group on a daily basis. Staff can also report to the
EMICT in the WeChat group any time. Protocols for each modality and infection control
instructions are posted on the walls in all examination rooms. The EMICT periodically reminds
staff to undertake personal measures to reduce infection, such as wearing masks at all instances
in the radiology department and N95 masks if working in the contaminated area; not touching
the mask and the eyes; practicing hand hygiene; facing away from colleagues when eating,
drinking, and talking; and not using personal cell phones while on duty. In addition, the chief thoracic radiologist provided lectures on all radiologists and
technologists on typical CT findings of COVID-19 infection using materials developed in
Wuhan, the epicenter of the outbreak in China. CT examination procedures
There are two sets of procedures for CT examination: the fever-CT procedure and routine CT
procedure for those not suspected of COVID-19. The fever-CT procedure for suspected or confirmed COVID-19 (Figure 2)
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Before the fever-CT technologist operates the equipment, he or she should wear personal
protective equipment according to three-level protection standard [8]. Before the CT
examination of patients with suspected and confirmed COVID-19 begins, the fever tent or
isolation ward notifies the radiologist in advance. The fever-CT technologist checks the
equipment and prepares to disinfect the imaging equipment immediately after the examination. The patient enters the fever-CT waiting area through the fever access area. If the patient
can get onto and off the examination table by themselves, the patient is allowed to do so. If the
patient cannot get onto or off the examination table independently, the person accompanying
the patient assists the patient, rather than the technologist. The technologist checks the patient
information and, using an intercom system in the examination room, asks the patient to remove
any metal ornaments on the neck and chest. Also, by intercom, the technologist trains the
patient to hold his or her breath during the examination. The technologist uses a low-dose chest CT protocol to scan the patient. After scanning, the
original images are reconstructed as 1 mm-thick layers. The technologist browses the images to
ensure that their quality meets the diagnostic requirements and then guides the patient to leave
through the fever access area. The disposable sheets for patient examination are changed after
each patient. The equipment is disinfected according to the procedure below. To protect themselves, the technologists assigned to the fever-CT wear N95 mask and
other personal protection as established by the EMICT. The CT procedure for regular patients (figure.3)
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Some patients with COVID-19 have no symptoms, and they may call at the general clinic for
other reasons. The following CT procedure is applicable under these circumstances:
When the patient makes an appointment for examination, the staff asks the patient about
their epidemiological history, symptoms, and signs. If suspected criteria are met, the patient
will be sent to the fever tent for further screening. When a patient presents to the radiology
department entrance, his/her temperature is measured. If the temperature is higher than 37.2 , ℃
the patient is sent to the fever tent for further investigation. Those with no exposure history, suspicious symptoms or fever are screened in one of the
non-contaminated CT scanners. The technologists assigned to these scanners wear surgical
masks. All patients and the person accompanying them are required to wear surgical masks. After the CT examination, the technologist browses the images quickly. If the CT appearance is
typical of lung infection, the technologist immediately reports it to the chest radiologist on duty
and asks the patient to wait in the CT examination room. If the chest radiologist does not
suspect COVID-19 infection, the patient can leave the CT examination room. If the chest
radiologist does suspect COVID-19 infection, the technologist immediately reports it to the
EMICT and sends the patient to the fever tent. The floor and equipment in the CT examination
room are disinfected according to regulations, and air disinfection is conducted for 30 min
before examining other patients. These CT scanners are considered noncontaminated (not
fever-CTs) after these sterilization procedures. Fever-DR examination procedure
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The COVID-19 guideline of the NHC does not recommend chest DR because its ability in
diagnosing COVID-19 is limited. At our hospital, we only use mobile DR units to provide
bedside examination for critically ill patients. The technologist operating the mobile DR
wears personal protective equipment according to the three-level protection standard and
sterilizes the mobile DR according to the ward management requirements as described below. Equipment and environment disinfection procedures
Routine disinfection procedure [9]
1) Object surface disinfection: Object surface is wiped with 1000mg/L chlorine-containing
disinfectant, wipe twice with 75% ethanol for non-corrosion resistance, once /4 hours. 2) Equipment disinfection: The equipment in the contaminated area are wiped with
2000mg/L chlorine-containing disinfectant. The DR and CT gantry in the contaminated
area are wiped with 75% ethanol. The equipment in the buffer area is wiped with
500-1000mg/L chlorine-containing disinfectant or alcohol-containing disposable
disinfectant wipes twice a day. 3) Air disinfection: Turning off all central air conditioners to prevent air contamination with
each other. Polluted area: open the door for ventilation, each time more than 30 minutes,
once /4 hours; The air sterilizer is continuously sterilized or the ultraviolet ray is
continuously used in the unmanned state for 60 minutes, four times a day, remembered to
close the inner shielding door when air disinfection. Other ambient air is sprayed with
1000mg/L chlorine-containing disinfectant and ventilated twice a day
4) Ground disinfection: The ground is wiped with 1000mg/L chlorine-containing
disinfectant, once /4 hours. 5) When contaminated, disinfect at any time. In case of visible contamination, disposable
absorbent materials should be used first to completely remove the pollutants, and then a
cloth soaked with 2000mg/L chlorine-containing disinfectant should be used for 30
minutes before wiping. 11
Fever-CT disinfection procedures after examination
In addition to the above, disinfect the examination bed and ground with chlorinated disinfectant
containing 2000mg/L [10]. Noncontaminated CT disinfection procedures after suspected COVID-19 case examination
In addition to the above routine disinfection procedure, air disinfection is conducted for 30 min
before examining other patients. Results
From January 21, 2020 when screening for epidemiological history or symptoms
suspicious for COVID-19, to March 9, 2020, our hospital screened a total of 7,203 individuals
and confirmed 24 cases of COVID-19. Of these, 3,083 people underwent fever-CT
examinations. Including the initial examination and reexamination, the total number of fever
CT examination numbered 3,340. The fever-CT scanned a patient approximately every 21.5
minutes. As a result of our precautions, none of the staff of the radiology department developed
symptoms suspicious for COVID-19. The fever-CT technologist, with the highest probability
of exposure, remains PCR negative. Discussion
It has been 17 years since the severe acute respiratory syndrome (SARS) epidemic, the last
national spread of severe infectious disease, broke out. Currently, the Chinese people are
panicking again. The speed and extent by which COVID-19 has spread in 2 months are
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unprecedented, beyond those of SARS, and this has been aided by its contagious nature and
rapid spread via droplets and contact. The droplet mode of transmission means that a person can
be infected easily by means of casual contact or even fomites on contaminated environmental
surfaces. Another theory has yet to be proved: aerosol propagation. How radiology departments respond to any infectious disease outbreak is determined
primarily by the estimated risk of cross-infection to the staff and other patients. Appropriate
precautions taken only by staff in direct contact with patients may be adequate when the risk is
low. The strongest measures need to be implemented to limit the spread of the disease when the
risk is high. With severe infectious diseases such as COVID-19, the highest level of infection
control measures must be implemented; these include providing adequate standard protective
equipment, training staff, and instituting proper emergency plans. Once a contagious infectious disease has been identified, the EMICT must consider four
main areas of response: data gathering, collaboration, needs assessment, and expert advice [10]. Data gathering includes dissemination of up-to-date case definitions and information about
confirmatory tests to all staff with direct patient contact to allow appropriate barrier precautions
to be taken. All typical and atypical imaging features of the disease should be made known to
all radiologists to assist in recognition of the disease on images and to allow accurate reporting
of these findings. We have stored images of all probable cases of COVID-19 in the PACS so
that these images were readily available for any radiologist to review, and images from
previous imaging studies are also available for comparison. Collaboration with the radiology departments of other hospitals is very important because
patients may initially present to different centers, depending on geographic location and travel
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distance. These patients may be few in number at a single hospital, but if data from patients at
several hospitals are available, a more accurate overall understanding of both imaging features
and epidemiology can be achieved. Dissemination of this information to all healthcare facilities
will also lead to early recognition of the disease, and appropriate isolation measures may be
instituted. The Internet and social media apps, especially WeChat, have been used for distribution of
medical information, and because the exchange of information regarding infectious disease
outbreaks is almost instantaneous, it is an indispensable tool for radiologists. In fact, within a
month of the outbreak, the hospital that received the most infected patients from the source of
the outbreak made a PowerPoint presentation of the CT manifestations of COVID-19, which
was shared via WeChat and disseminated across the country in a very short time. Subsequently,
COVID-19-teaching PowerPoint presentations from various hospitals appeared and were
quickly shared via WeChat. Our diagnostic process is limited as chest CT along is not diagnostic of COVID-19
because of lack of imaging specificity. But when combined with other epidemiological,
clinical, laboratory and virus nucleic acid information, typical chest CT imaging findings are
helpful for making the diagnosis. In our opinion, the major role of chest CT is to understand the
extent and dynamic evolution of lung lesions induced by COVID-19. The reasons why we
adopted the low-dose chest CT scan protocol are as follows: low-dose chest CT has been
widely used in the screening of early lung cancer. It is well known that many early lung cancers
are ground-glass opacities (GGO), so we believe that low-dose screening is also applicable for
COVID-19. In addition, considering the rapid development of COVID-19, many CT
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examinations may be conducted in the same individual to monitor disease progress. Low-dose
scanning can reduce the radiation damage to patients. 
Although the processes we established minimized the exposure of hospital staff, ancillary
personnel and other patients, it remains limited as follows. Sichuan province is not the center of
the epidemic. The number of patients with COVID-19 whom we have treated has not been
high, and most cases are from other provinces of China. However, we believe that our
experience in management, the reconfiguration of our radiology department, and the workflow
changes implemented in the current COVID-19 situation are useful for other radiology
departments that must prepare for dealing with patients with COVID-19. While no radiology
personnel developed symptoms suspicious for or were confirmed as having COVID-19, there
may be asymptomatic personnel. REFERENCES
1. National Health Commission of the People’s Republic of China.(2020). March 12: Daily briefing
on novel coronavirus cases in China. Retrieved from
http://en.nhc.gov.cn/2020-03/12/c_77618.htm. Accessed March 11, 2020. 2. World Health Organization. (2020). Coronavirus disease 2019 (COVID-19) Situation Report-52. Retrieved from
https://www.who.int/docs/default-source/coronaviruse/20200312-sitrep-52-covid-19.pdf?sfvrsn=e
2bfc9c0_2 9. Accessed March 11, 2020. 3. National Health Commission of the People’s Republic of China.(2020). Latest developments in
epidemic control on Feb 15. Retrieved from http://en.nhc.gov.cn/2020-02/16/c_76622. Accessed
March 11, 2020. 15
4. Health Commission of the People’s Republic of China.(2020).

Question: What is the reason to adopt low-dose CT?
low-dose chest CT has been
widely used in the screening of early lung cancer. It is well known that many early lung cancers
are ground-glass opacities (GGO), so we believe that low-dose screening is also applicable for
COVID-19. In addition, considering the rapid development of COVID-19, many CT
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examinations may be conducted in the same individual to monitor disease progress. Low-dose
scanning can reduce the radiation damage to patients.