At the radiological unit of the hospital, gamma-devices of radiotherapy of "Agat" type and other closed sources of ionising radiation are used for treatment of malignant neoplasms. What are the measures to be taken to protect personnel at the time of work with radioactive sources of such type?

Answer options

1. The increase of distance to the source and individual hygiene compliance
2. Shortening of working time and screening of the source
3. Systematic cleansing of surfaces from the radioactive contamination and shortening of working time
4. Capsulation of devices and organisation of room ventilation
5. Screening of the source and the use of means of individual protection of respiration organs