A scanning system that includes an illumination module that is configured to scan, at a first direction, an elongated radiation spot over an object; and a collection module that is configured to (a) collect a collected radiation beam from the object, and (b) optically manipulate the collected radiation beam to provide a counter-scan beam is directed towards a set of detection units and has a focal point that is positioned at a same location regardless of the propagation of the elongated radiation spot along the first direction.