RF volume resonator system for use in an MR imaging system, the RF volume resonator system comprising: - a multi-port RF volume resonator (40, 50; 60), comprising a number of conductor elements which are electromagnetically coupled to each other, comprising - a plurality of transmit and/or receive channels (TCh1/RCh1,...TChn/RChn), - a plurality of ports (P1, P2,..Pn) which are positioned at the resonator for exciting RF signals by means of transmit channels and/or receiving MR signals by means of receive channels, of said plurality of transmit and/or receive channels (TCh1/ RCh1,...TChn/RChn), - with which each of said plurality of transmit and/or receive channels (TCh1/RCh1,... TChn/RChn) a port (P1, P2,..Pn) is related and the transmit and/or receive channels (TCh1/RCh1,... TChn/RChn) each at least comprise an ON/OFF switch for connecting and disconnecting each one of the transmit channels with each related port (P1, P2,..Pn) by switching the related ON/OFF switch between an ON and an OFF state and/or each one of the receive channels with each related port (P1, P2,..Pn) by switching the related ON/OFF switch between an ON and an OFF state, respectively, wherein the ON/OFF switches are configured to be switched between the ON and the OFF state independently from each other by means of each an individual switch signal, and - a control unit, comprising means for generating the switch signals for selecting at least two of the ports of the RF resonator for connecting each one of the selected ports with the related transmit channel for exciting RF signals and/or with the related receive channels for receiving MR signals for conducting an MR imaging of an examination object, characterized in that: - the control unit is provided for selecting at least two ports of the RF resonator for connecting with each one of the related transmit channels in dependence on physical properties like volume, weight, size and water/fat ratio of an examination object such that the homogeneity of a resonant RF mode excited by the RF volume resonator (40, 50; 60) is a maximum and/or the resulting value of the SAR of the examination object is a minimum. - a multi-port RF volume resonator (40, 50; 60), comprising a number of conductor elements which are electromagnetically coupled to each other, comprising - a plurality of transmit and/or receive channels (TCh1/RCh1,...TChn/RChn), - a plurality of ports (P1, P2,..Pn) which are positioned at the resonator for exciting RF signals by means of transmit channels and/or receiving MR signals by means of receive channels, of said plurality of transmit and/or receive channels (TCh1/ RCh1,...TChn/RChn), - with which each of said plurality of transmit and/or receive channels (TCh1/RCh1,... TChn/RChn) a port (P1, P2,..Pn) is related and the transmit and/or receive channels (TCh1/RCh1,... TChn/RChn) each at least comprise an ON/OFF switch for connecting and disconnecting each one of the transmit channels with each related port (P1, P2,..Pn) by switching the related ON/OFF switch between an ON and an OFF state and/or each one of the receive channels with each related port (P1, P2,..Pn) by switching the related ON/OFF switch between an ON and an OFF state, respectively, wherein the ON/OFF switches are configured to be switched between the ON and the OFF state independently from each other by means of each an individual switch signal, and - a control unit, comprising means for generating the switch signals for selecting at least two of the ports of the RF resonator for connecting each one of the selected ports with the related transmit channel for exciting RF signals and/or with the related receive channels for receiving MR signals for conducting an MR imaging of an examination object, characterized in that: - the control unit is provided for selecting at least two ports of the RF resonator for connecting with each one of the related transmit channels in dependence on physical properties like volume, weight, size and water/fat ratio of an examination object such that the homogeneity of a resonant RF mode excited by the RF volume resonator (40, 50; 60) is a maximum and/or the resulting value of the SAR of the examination object is a minimum.