Abstract: The apparatus including a mainly cylindrical RF coil (9) having a central axis (33) which extends in its longitudinal direction, which coil has a number of axial conductor elements (35) which extend parallel to the central axis across a mainly cylindrical surface, and end conductor elements (37) which extend around the central axis near the ends of the axial conductor elements. The axial conductor elements (35) extend pair-wise diametrically relative to the central axis and the RF coil (9) is arranged to generate a substantially cosinusoidal current distribution as a function of the position of the axial conductor elements on the circumference of the cylinder in order to enable generation and/or reception of a substantially uniform RF magnetic field which is oriented perpendicularly to the cylinder axis. Each of the end conductor elements (37) consists of a number of loop conductor segments (39) which corresponds to the number of pairs of axial conductor elements (35).