A medical instrument comprising: - a LINAC with an X-ray source configured for directing X-ray radiation at a target zone, wherein the LINAC is adapted for rotating the X-ray source about a rotational axis; and - a magnetic resonance imaging system configured for acquiring magnetic resonance data with a magnetic resonance antenna from an imaging zone, wherein the target zone is within the imaging zone, wherein the magnetic resonance imaging system comprises a magnet configured for generating a magnetic field within the imaging zone, wherein the X-ray source is adapted for rotating at least partially about the magnet; wherein the magnetic resonance imaging system comprises the magnetic resonance antenna, wherein the magnetic resonance antenna is a surface coil, wherein the magnetic resonance antenna is a receive coil, wherein the magnetic resonance antenna comprises: - an antenna element (104, 404) - a preamplifier for the antenna element; and - a coil former configured for supporting the antenna element, wherein the coil former is formed from a porous material, wherein the coil former is rigid, wherein the coil former is divided into an irradiation zone and at least one reduced radiation zone (202, 206), wherein the irradiation zone is configured to enable the X-ray radiation to pass through the magnetic resonance antenna while minimally disturbing an X-ray radiation dose delivery to the target zone, wherein the preamplifier for the antenna element is located within the at least one reduced radiation zone, wherein the antenna element is located at least partially within the irradiation zone, wherein the coil former has a perimeter, wherein the irradiation zone extends continuously from a first edge of the perimeter to a second edge of the perimeter, and wherein the first edge and the second edge are opposing edges. - a LINAC with an X-ray source configured for directing X-ray radiation at a target zone, wherein the LINAC is adapted for rotating the X-ray source about a rotational axis; and - a magnetic resonance imaging system configured for acquiring magnetic resonance data with a magnetic resonance antenna from an imaging zone, wherein the target zone is within the imaging zone, wherein the magnetic resonance imaging system comprises a magnet configured for generating a magnetic field within the imaging zone, wherein the X-ray source is adapted for rotating at least partially about the magnet; wherein the magnetic resonance imaging system comprises the magnetic resonance antenna, wherein the magnetic resonance antenna is a surface coil, wherein the magnetic resonance antenna is a receive coil, wherein the magnetic resonance antenna comprises: - an antenna element (104, 404) - a preamplifier for the antenna element; and - a coil former configured for supporting the antenna element, wherein the coil former is formed from a porous material, wherein the coil former is rigid, wherein the coil former is divided into an irradiation zone and at least one reduced radiation zone (202, 206), wherein the irradiation zone is configured to enable the X-ray radiation to pass through the magnetic resonance antenna while minimally disturbing an X-ray radiation dose delivery to the target zone, wherein the preamplifier for the antenna element is located within the at least one reduced radiation zone, wherein the antenna element is located at least partially within the irradiation zone, wherein the coil former has a perimeter, wherein the irradiation zone extends continuously from a first edge of the perimeter to a second edge of the perimeter, and wherein the first edge and the second edge are opposing edges.