The invention relates to means for determining the spatial configuration of a biological body (P) on a surface, particularly on the surface of a patient support (150). One embodiment of these means is a sensor system (110) that can be applied to a patient support (150) and that comprises a plurality of sensor units (111), wherein each of these sensor units (111) has an adjacent sensitive zone (112) in which the presence of a biological body (P) induces a detection signal. The sensor unit may particularly comprise a microwave coil (111).