A portable mechanical high-precision device for performing circular or helical scanning of a patients organ or body surface for tissue diagnosis and/or treatment includes a substantially hollow housing for accommodating the organ therein and a securing unit for securing the housing to the organ or body surface during scanning so that the organ or body surface is substantially fixed relative to the housing. At least one drive unit is attached to the housing and to at least one scan head for allowing unlimited rotation of the scan head relative to the housing.
