Abstract: When performing nuclear (e.g., SPECT or PET) and CT scans on a patient, a volume cone-beam CT scan is performed using a cone-beam CT X-ray source (20) and an offset flat panel X-ray detector (22). A field of view of the X-ray source overlaps a field of view of two nuclear detector heads (18), and the offset of the X-ray detector (22) minimizes interference with nuclear detector head movement about a rotatable gantry (16). Additionally, a locking mechanism (80) provides automatically locking of the X-ray detector (22) in each of a stowed and operation position, improving safety and CT image quality.

Abstract: A apparatus particularly well suited for use in medical imaging includes radiation sensitive detectors (40, 50) which detect gamma radiation indicative of radionuclide decays in an examination region (30). The detectors (40, 50) are supported by generally c-shaped support (70) for rotation about a detector rotation axis (35). The support (70) is farther attached to a pivot joint (77) which allows adjustment of the detector rotation axis (35). The support (70) may also be translated in two degrees of freedom to so that the detectors (40, 50) orbit the examination region (20) in a non-circular orbit.

Abstract: A gamma camera (8, 180) includes at least one radiation detector head (10, 12, 210, 212). At least one such radiation detector head (10, 12, 210, 212) includes a plurality of capacitive elements (60, 260, 76, 276) disposed over at least a radiation sensitive portion (50) of the radiation detector head. A proximity sensor monitor (62) is coupled with the plurality of capacitive elements to detect proximity of a subject to the radiation detector head based on a measured electrical characteristic of the capacitive elements. A collision sensor monitor (64) is coupled with the plurality of capacitive elements to detect conductive electric current flowing between spaced apart parallel conductive plates (66, 67) of the capacitive element responsive to mechanical deformation of the spacing between the plates.

Abstract: A computed tomography acquisition geometry provides an increased field of view (218). A radiation source (202, 702) such as an x-ray source and a radiation detector (204, 704) are displaced from the imaging center (214). In one implementation, the central ray (216) of a radiation beam (212) is parallel to the plane of the detector (204, 704) at the detector midpoint (219, 719), but is displaced from the imaging center.

Abstract: When performing nuclear (e.g., SPECT or PET) and CT scans on a patient, a volume cone-beam CT scan is performed using a cone-beam CT X-ray source (20) and an offset flat panel X-ray detector (22). A field of view of the X-ray source overlaps a field of view of two nuclear detector heads (18), and the offset of the X-ray detector (22) minimizes interference with nuclear detector head movement about a rotatable gantry (16). Additionally, a locking mechanism (80) provides automatically locking of the X-ray detector (22) in each of a stowed and operation position, improving safety and CT image quality.

Abstract: A computed tomography acquisition geometry provides an increased field of view (218). A radiation source (202, 702) such as an x-ray source and a radiation detector (204, 704) are displaced from the imaging center (214). In one implementation, the central ray (216) of a radiation beam (212) is parallel to the plane of the detector (204, 704) at the detector midpoint (219, 719), but is displaced from the imaging center.

Abstract: A gamma camera (8, 180) includes at least one radiation detector head (10, 12, 210, 212). At least one such radiation detector head (10, 12, 210, 212) includes a plurality of capacitive elements (60, 260, 76, 276) disposed over at least a radiation sensitive portion (50) of the radiation detector head. A proximity sensor monitor (62) is coupled with the plurality of capacitive elements to detect proximity of a subject to the radiation detector head based on a measured electrical characteristic of the capacitive elements. A collision sensor monitor (64) is coupled with the plurality of capacitive elements to detect conductive electric current flowing between spaced apart parallel conductive plates (66, 67) of the capacitive element responsive to mechanical deformation of the spacing between the plates.

Abstract: A radiation detector package includes a radiation-sensitive solid-state element (10) having a first electrode (12) and a pixelated second electrode (14) disposed on opposite principal surfaces of the solid-state element. An electronics board (20) receives an electrical signal from the solid-state element responsive to radiation incident upon the radiation-sensitive solid-state element. A light-tight shield (40, 40?) shields at least the radiation-sensitive solid-state element from light exposure and compresses an insulating elastomer and metal element connector (30, 32) between the pixilated electrode (14) and contact pads (24) on the electronics board.

Abstract: A system for generating registered diagnostic images (58, 62), such as nuclear and magnetic resonance (MR) images, of a subject includes a nuclear imaging device (10) for generating emission diagnostic images (58) and optionally also intermediate transmission or emission images (56). A second imaging device (12), such as an MR imaging device generates magnetic resonance diagnostic images (62) and optionally also intermediate images which are more readily registered with images from the nuclear imaging device than the diagnostic MR images. Processing for the images includes a preprocessing portion (64) for generating a transform for aligning common anatomical structures in images (56, 58, 60, 62) generated by the nuclear imaging device and the MR imaging device and a diagnostic image registration portion for applying the transform to bring the emission and magnetic resonance diagnostic images into registration (58, 62).

Abstract: A apparatus particularly well suited for use in medical imaging includes radiation sensitive detectors (40, 50) which detect gamma radiation indicative of radionuclide decays in an examination region (30). The detectors (40, 50) are supported by generally c-shaped support (70) for rotation about a detector rotation axis (35). The support (70) is farther attached to a pivot joint (77) which allows adjustment of the detector rotation axis (35). The support (70) may also be translated in two degrees of freedom to so that the detectors (40, 50) orbit the examination region (20) in a non-circular orbit.

Abstract: method A first image of a moving object is acquired by of a first imaging method, e.g by PET or SPECT imaging. The first image contains artifacts caused by object motion. From two further images acquired by a second imaging method, e.g. C.T. or M.R., and representing the object in respective states of motion, a motion model is formed. The information contents of either the first image or a combination image, formed from the first image and the two further images, and the motion model is enhanced.

Abstract: A system calibrates a solid state detector (20) for a radiation imaging device (10) in a single acquisition. A calibration phantom (40) emits radiation concurrently at at least first and second characteristic energy levels. A nuclear camera (16) generates associated sets of radiation data spanning both the first and second energy levels from the emitted radiation that is received by solid state detector (20). A means (64) determines associated centers of energy peaks and energy values of the generated data sets. A calibration means (80) calibrates at least one of gain, offset, performance and dead pixel correction based on the determined centers and peaks of the acquired data sets.

Abstract: A nuclear medicine imaging system that includes a plurality of detectors arranged about an imaging region. A transmission source can be provided opposite the detectors and rotating about the imaging region to obtain different imaging angles. The nuclear imaging system provides for the ability to acquire high sensitivity transmission data with high emission data spatial resolution.

Abstract: Gamma radiation events are received individually at elements of a detector array (18) at least one of the elements (P0) being defective. Each detector element converts incident radiation into a radiation event signal which is digitized by an analog-to-digital converter (42) into a coordinate position (x,y) on the detector array and energy (z). An event generator (48) generates radiation event signals for each defective element based on radiation events received at contributing elements, e.g., nearest neighbor elements (P1-P8). In a preferred embodiment, the contribution from each of the contributing elements is randomized by passing a token (56) among positions of a table (54) corresponding to each of the contributing elements. Each time a radiation event is received at the contributing element whose corresponding table position holds the token, that event also generates an event signal for the defective element and the token is passed (58).

Abstract: A nuclear medicine imaging system includes the capability to correct for the deadtime, including the capability to correct for spatial variations in deadtime across the imaging surface of a detector. The imaging system includes one or more radiation detectors, each using a large, monolithic scintillation crystal. Each detector has deadtime associated with it. A given detector is used to acquire an energy profile of a patient based on emission radiation. The detector includes a number of timing channels. The energy profile is used to select a zone influence map indicating the extent of spatial overlap in response between the various timing channels. Emission data of the patient is then acquired during an emission scan. During acquisition of the emission data, a rate meter assigned to each timing channel samples the number of counts associated with each timing channel to acquire deadtime data.

Abstract: An apparatus and method for reducing the non-uniformity of a positron emission tomography (“PET”) image is described. The event detector system comprises a detector having a plurality of zones, each zone comprising a plurality of detector devices. The event detector system also comprises a threshold circuit coupled to a detector device of the detector. Additionally, the event detector system comprises a summation circuit coupled to the threshold circuit.

Abstract: An event detector method and apparatus are described. One embodiment includes a first detector that includes a plurality of zones. Each zone includes a plurality of detector devices, wherein each zone generates a zone trigger signal when an event is detected by a detector device in the zone. The embodiment further includes a first energy source coupled to the first detector, wherein when the first energy source is active, events occur that are detectable by the first detector. A calibration circuit is coupled to the first detector, to perform timing calibration of zone trigger signals of zones of the first detector with respect to timing of a reference zone trigger signal of the predetermined reference zone of the first detector, wherein the zone trigger signals and the reference zone trigger signal are generated when an event is detected.

Abstract: A method and apparatus for selectively integrating PMT channel signals in a gamma camera system are described. A trigger word is decoded to determine which of multiple PMT channels are affected by a given scintillation event. When two scintillation events overlap both spatially and temporally, only those channels which are affected by both events stop integrating in response to the second event. Pre-pulse pile-up is corrected by removing the tail of a preceding pulse from a current pulse using an approximation of the tail of the preceding pulse based upon the instantaneous energy of the current pulse and the current countrate. Extrapolation of the tail of the current pulse may also be performed in essentially the same manner.

Abstract: A technique for correcting for random coincidences in a gamma camera system is provided. The system includes a pair of scintillation detectors coupled to a processing system and is configured to detect radiation coincidences. Each detector generates trigger pulses in response to scintillation events to generate a plurality of event-based trigger pulses. Each detector includes a pulse generator, which generates a plurality of artificial trigger pulses. When an artificial trigger pulse in one detector occurs in coincidence with an event-based trigger pulse in the other detector, data is registered by the corresponding detectors, and the artificial trigger pulse is associated with a predetermined energy level. The data processing system examines the data to identify singles events that were registered as a result of artificial trigger pulses and prevents such singles events from contributing to the coincidence images. Instead, such singles events are used to generate a singles image for each detector.

Abstract: A method and apparatus are provided for detecting scintillation events in a gamma camera detector using virtual photomultiplier tubes (PMTs). The gamma camera detector includes multiple real PMTs within the actual field of view of the detector as well as multiple virtual PMTs defined outside the actual field of view. In response to a scintillation event occurring near the edge of the field of view, one of the real PMTs responding to the event is identified. The event is then mapped to one or more virtual PMTs based on the identified real PMT. Data representing a response of the virtual PMT is then generated based on a response of a corresponding one of the real PMTs. Data representing responses of both the affected real PMTs and selected ones of the virtual PMTs are used in a centroid computation for the event, to increase the effective field of view of the detector.