Inclusion Criteria:

1. Have had a positive test confirming the diagnosis of COVID-19;

2. Have had clinical signs of severe acute respiratory syndrome or pneumonia (dyspnea,
cough, with need for oxygen support at the time of enrollment);

3. Have visible consolidations/ground glass opacities on chest x-ray or computed
tomography;

4. Have been on ventilator support for no longer than 5 calendar days prior to the
schedule date of delivery of low-dose radiation therapy;

5. They voluntarily participate in this clinical trial, gave informed consent and
signed the informed consent form.

Exclusion Criteria:

1. Have received chest radiotherapy before

2. Bacteria, fungi and other infections other than novel coronavirus infection;

3. Combined with severe primary diseases such as cardiovascular, cerebrovascular,
liver, kidney, hematopoietic and endocrine system or immune system diseases (the
upper limit of liver function ALT and AST> normal reference value, the upper limit
of Scr> normal reference value, poor blood glucose control);

4. Mental retardation, mental disorders;

5. Planned pregnancy, pregnancy, lactation women and during the trial;

6. Allergy constitution or allergy to the drug ingredients and excipients of this test;

7. Participated in other clinical trials in the recent 1 month;

8. The Investigator does not considered appropriate to participate in this clinical
trial.