The authors proposed drawing up maps of dose rate distribution under the conditions simulating patient's irradiation for each gamma therapeutic unit in order to estimate a degree of danger of excess irradiation of medical staff and patients during patient's evacuation resulting from a defective unit (incomplete closure of locks in distant irradiation and sources getting stuck in endostats in interstitial therapy). The timing of measures for evacuation of a patient from an emergency room made it possible to calculate accurately equivalent doses to which a radiologist, a technician and a patient were exposed.