The present invention relates to an apparatus and a method for detecting magnetic particles in a field of view (28). More specifically the present invention relates to the field of magnetic particle imaging (MPI). The method and arrangement according to the present invention use an acoustic MPI detection technique which detects acoustic emissions of a magnetic tracer material in an MPI setup. The apparatus according to the present invention therefore comprises an acoustic signal receiver (160) for acquiring acoustic detection signals which detection signals depend on the magnetization in the field of view (28) which magnetization is influenced by the change in the position in space of the first and second sub-zone (52 54). Fig.7
