Patent ID: 7492866

Claim:
A collision detecting device for a radiation treatment apparatus, comprising a radiation unit having an internal space for directing radiation beams towards a radiological focus in the internal space for treatment of a target in a patient's body therein, wherein the collision detecting device functions to detect whether any body part or any equipment comes into contact with surfaces defining the internal space of the radiation unit when moving the patient inside the space to position the target to be treated in the radiological focus, wherein the collision detecting device comprises a collision detecting unit being electrically conductive at least on its outer surface and having a size smaller than the internal space of the radiation unit, so as to be insertable into the internal space and held in an electrically insulating manner in respect of the radiation unit so that its outer electrically conductive surface is held at a distance from the inner surface of the radiation unit, and being connected to an electrical voltage supply in order to detect if the outer surface of the collision detecting unit abuts against the inside surface of the radiation unit due to deformation or displacement of the collision detecting unit caused by the body part or any equipment attached thereto.