A body-supporting couch and a radiation system incorporating such a couch are disclosed. The couch comprises a first and second couch unit, respectively. The first couch unit comprises a first table top support and a first elongated table top portion extending horizontally from the first support. The first table top portion is provided with a first docking element arranged in an end. Element for moving the first table top portion relative the first table top support along its longitudinal axis is arranged in the first couch unit. The second couch unit comprises a second table top support, which supports a second table top portion, provided with a second docking element in an end facing the first couch unit. Upon contact, the first docking element engages with the second docking element and the first table top portion connects with the second table top portion forming a stable continuous table top.