Abstract: A generally cylindrical set of coil windings includes primary coil windings and shield coil windings at a larger radial position than the primary coil windings, and an arcuate or annular central gap that is free of coil windings, has an axial extent of at least ten centimeters, and spans at least a 180° angular interval. Connecting conductors disposed at each edge of the central gap electrically connect selected primary and secondary coil windings. In a scanner setting, a main magnet is disposed outside of the generally cylindrical set of coil windings. In a hybrid scanner setting, an annular ring of positron emission tomography (PET) detectors is disposed in the central gap of the generally cylindrical set of coil windings.

Abstract: A generally cylindrical set of coil windings includes primary coil windings and shield coil windings at a larger radial position than the primary coil windings, and an arcuate or annular central gap that is free of coil windings, has an axial extent of at least ten centimeters, and spans at least a 180° angular interval. Connecting conductors disposed at each edge of the central gap electrically connect selected primary and secondary coil windings. In a scanner setting, a main magnet is disposed outside of the generally cylindrical set of coil windings. In a hybrid scanner setting, an annular ring of positron emission tomography (PET) detectors is disposed in the central gap of the generally cylindrical set of coil windings.

Abstract: An imaging system comprises: a magnetic resonance scanner (30) having a cylindrical bore (36) defining a cylinder axis (DA), the magnetic resonance scanner having a gradient coil (10, 10?) defining an isocenter (64) within the bore and an isoplane (66) passing through the isocenter and oriented transverse to the cylinder axis; a ring of radiation detectors (60a, 60b, 60?) arranged concentric with the cylindrical bore and configured to detect radiation emanating from within the bore; and a generally annular electronic circuit board (62, 62?) arranged concentric with the cylindrical bore and centered on the isoplane, the generally annular electronic circuit board operatively connected with the ring of radiation detectors to generate electrical signals indicative of detection of radiation by the ring of radiation detectors.

Abstract: An imaging system includes positron emission tomography (PET) detectors (30) shrouded by broadband galvanic isolation (99) and coincidence detection electronics (50, 50ob), or other radiation detectors. A magnetic resonance scanner includes a main magnet (12, 14) and magnetic field gradient assembly (20, 20?, 22, 24) configured to acquire imaging data from a magnetic resonance examination region at least partially overlapping the examination region surrounded by the PET detectors. A radio frequency coil (80, 100) has plurality of conductors (66, 166) and a radio frequency screen (88, 188, 188EB, 188F) substantially surrounding the conductors to shield the coil at the magnetic resonance frequency. The radiation detectors are outside of the radio frequency screen. Magnetic resonance-compatible radiation collimators or shielding (60, 62) containing an electrically non-conductive and non-ferromagnetic heavy atom oxide material are disposed with the radiation detectors.

Abstract: In a hybrid PET-MR system, PET detector elements (30) are added in the bore (14), in close proximity to the gradient coils (16). Fluid coolant is supplied to transfer heat from the PET detector elements (30). Thermal insulation (80) insulates the fluid coolant and the PET detector elements (30) from the gradient coils (16). In some embodiments, a first coolant path (90) is in thermal communication with the electronics, a second coolant path (92) is in thermal communication with the light detectors, and a thermal barrier (94, 96) is arranged between the first and second coolant paths such that the first and second coolant paths can be at different temperatures (Te, Td). In some embodiments a sealed heat pipe (110) is in thermal communication with a heat sink such that working fluid in the heat pipe undergoes vaporization/condensation cycling to transfer heat from the detector elements to the heat sink.

Abstract: A generally cylindrical set of coil windings includes primary coil windings and shield coil windings at a larger radial position than the primary coil windings, and an arcuate or annular central gap that is free of coil windings, has an axial extent of at least ten centimeters, and spans at least a 180° angular interval. Connecting conductors disposed at each edge of the central gap electrically connect selected primary and secondary coil windings. In a scanner setting, a main magnet is disposed outside of the generally cylindrical set of coil windings. In a hybrid scanner setting, an annular ring of positron emission tomography (PET) detectors is disposed in the central gap of the generally cylindrical set of coil windings.

Abstract: An imaging system comprises: a magnetic resonance scanner (30) having a cylindrical bore (36) defining a cylinder axis (DA), the magnetic resonance scanner having a gradient coil (10, 10?) defining an isocenter (64) within the bore and an isoplane (66) passing through the isocenter and oriented transverse to the cylinder axis; a ring of radiation detectors (60a, 60b, 60?) arranged concentric with the cylindrical bore and configured to detect radiation emanating from within the bore; and a generally annular electronic circuit board (62, 62?) arranged concentric with the cylindrical bore and centered on the isoplane, the generally annular electronic circuit board operatively connected with the ring of radiation detectors to generate electrical signals indicative of detection of radiation by the ring of radiation detectors.

Abstract: An imaging system includes positron emission tomography (PET) detectors (30) shrouded by broadband galvanic isolation (99) and coincidence detection electronics (50, 50ob), or other radiation detectors. A magnetic resonance scanner includes a main magnet (12, 14) and magnetic field gradient assembly (20, 20?, 22, 24) configured to acquire imaging data from a magnetic resonance examination region at least partially overlapping the examination region surrounded by the PET detectors. A radio frequency coil (80, 100) has plurality of conductors (66, 166) and a radio frequency screen (88, 188, 188EB, 188F) substantially surrounding the conductors to shield the coil at the magnetic resonance frequency. The radiation detectors are outside of the radio frequency screen. Magnetic resonance-compatible radiation collimators or shielding (60, 62) containing an electrically non-conductive and non-ferromagnetic heavy atom oxide material are disposed with the radiation detectors.

Abstract: In a hybrid PET-MR system, PET detector elements (30) are added in the bore (14), in close proximity to the gradient coils (16). Fluid coolant is supplied to transfer heat from the PET detector elements (30). Thermal insulation (80) insulates the fluid coolant and the PET detector elements (30) from the gradient coils (16). In some embodiments, a first coolant path (90) is in thermal communication with the electronics, a second coolant path (92) is in thermal communication with the light detectors, and a thermal barrier (94, 96) is arranged between the first and second coolant paths such that the first and second coolant paths can be at different temperatures (Te, Td). In some embodiments a sealed heat pipe (110) is in thermal communication with a heat sink such that working fluid in the heat pipe undergoes vaporization/condensation cycling to transfer heat from the detector elements to the heat sink.

Abstract: In a radiation detector (10) for a time of flight positron emission tomography (PET) scanner (2), a radiation sensitive member (20) generates a signal (22) indicative of a radiation detection event. A time to digital converter (34) includes digital delay elements (40) operatively interconnected as a ring oscillator (36, 36?) and readout circuitry (50, 52, 60, 82, 84, 86, 88) configured to generate a timestamp for the radiation detection event based at least on a state of the ring oscillator when the signal is generated. Delay trim elements (46) operatively connected to the digital delay elements set a substantially common delay for the digital delay elements.

Abstract: In a radiation detector (10) for a time of flight positron emission tomography (PET) scanner (2), a radiation sensitive member (20) generates a signal (22) indicative of a radiation detection event. A time to digital converter (34) includes digital delay elements (40) operatively interconnected as a ring oscillator (36, 36?) and readout circuitry (50, 52, 60, 82, 84, 86, 88) configured to generate a timestamp for the radiation detection event based at least on a state of the ring oscillator when the signal is generated. Delay trim elements (46) operatively connected to the digital delay elements set a substantially common delay for the digital delay elements.