Some differences may exist between french and english regulations. Lessons learned are only a translation of those of french incident and are not adapt to english regulation.

pdf Exposure of a cleaner during calibration of a hospital CT scanner (68 kB)

Description of the incident

In a radiology department, an operator started the scanner calibration procedure and left her post for 15 minutes. The scanner calibration is performed between 7:00 and 8:00 a.m. before patients arrive, and the operator is alone during this procedure.

A cleaner from an external contractor entered the room, without having been advised of the on-going procedure.

Following this incident, the person responsible for radiation protection was informed and proceeded with an evaluation of the dose received by the cleaner. A warning sign was also posted on the door (which was also fitted with a lock).

Radiological consequences

The whole body dose was estimated to be a maximum of 35 microsieverts, based on pessimistic assumptions.

Lessons to be learned from the incident

An effective warning signal (audible and visible) during the emission of X-rays should be provided (at the time of this incident, this signaling was only required when the equipment was actually in use, ie not during calibration).

Access should be effectively restricted during a calibration procedure, and the operator should remain at the control panel.

Information regarding radiological risks should be provided to all staff, including ancillary staff such as cleaners, especially in the hospital environment. To this end, it is preferable that such staff are permanent (or at least are not changed frequently).

pdf Exposure of a cleaner during calibration of a hospital CT scanner (68 kB)