Abstract: A nuclear camera is provided with an open and flexible software architecture which enables users to readily understand, modify, and exchange data files. In a constructed embodiment the software architecture utilizes xml files which can be defined and read by a user using readily available tools and viewers. Both control data and image data can be formatted in this manner. An illustrated software architecture contains a directory of manufacturer-supplied xml control files, and a directory of user modified or created xml control files. This software architecture enables users to exchange protocol and image information over conventional communications networks such as the Internet.

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 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 gamma camera system is described in which multiple simultaneous acquisitions are performed based upon different characteristics for event data acquired by a common gantry behavior. The event data from a detector is selected for different images based upon characteristics such as gating, ungated, energy windows, or zooming.

Abstract: A gamma camera is provided in which the study protocol can be modified after the study has commenced and while event data is being acquired. In such a camera, study parameters such as the duration of the study, the number of image frames acquired, or the count criterion required to produce an image may be changed dynamically as the study proceeds. Thus, a nuclear study which is seen to be leading to unsatisfactory or less than optimal results may be altered during acquisition to increase the likelihood that diagnostically useful results will be produced.

Abstract: A nuclear camera system is provided in which the energy spectrum peaks identified by a camera detector head are automatically adjusted to account for drift and other sources of inaccuracy. Histograms of events detected by the photomultiplier tubes of the detector head are acquired continuously and updated periodically. A system operator initiates the adjustment with an autopeaking command which causes the system to ascertain the validity of the histogram data and, if it is valid, to determine a peak energy level. The determined level is compared to a theoretical value for an isotope present and the comparison is used to adjust the gain applied to energy data of the detector head.

Abstract: A nuclear camera system is provided in which the energy spectrum peaks identified by a camera detector head are automatically adjusted to account for drift and other sources of inaccuracy. Histograms of events detected by the photomultiplier tubes of the detector head are acquired continuously and updated periodically. A system operator initiates the adjustment with an autopeaking command which causes the system to ascertain the validity of the histogram data and, if it is valid, to determine a peak energy level. The determined level is compared to a theoretical value for an isotope present and the comparison is used to adjust the gain applied to energy data of the detector head.

Abstract: A nuclear camera is provided with an open and flexible software architecture which enables users to readily understand, modify, and exchange data files. In a constructed embodiment the software architecture utilizes xml files which can be defined and read by a user using readily available tools and viewers. Both control data and image data can be formatted in this manner. An illustrated software architecture contains a directory of manufacturer-supplied xml control files, and a directory of user modified or created xml control files. This software architecture enables users to exchange protocol and image information over conventional communications networks such as the Internet.

Abstract: A gamma camera is provided in which the study protocol can be modified after the study has commenced and while event data is being acquired. In such a camera, study parameters such as the duration of the study, the number of image frames acquired, or the count criterion required to produce an image may be changed dynamically as the study proceeds. Thus, a nuclear study which is seen to be leading to unsatisfactory or less than optimal results may be altered during acquisition to increase the likelihood that diagnostically useful results will be produced.

Abstract: A gamma camera system is described in which multiple simultaneous acquisitions are performed based upon different characteristics for event data acquired by a common gantry behavior. The event data from a detector is selected for different images based upon characteristics such as gating, ungated, energy windows, or zooming.

Abstract: A method of correcting for deadtime and for emission contamination of a transmission scan in a nuclear camera system is provided. The transmission scan is used to correct positron emission tomography (PET) images for attenuation. The camera system includes two detectors and two corresponding single-photon point sources that are collimated to produce fanbeam illumination profiles. A transmission detection window and an emission contamination detection window is defined on each detector. Radiation from each source is scanned axially across the field of view of the corresponding detector in synchronization with the corresponding transmission detection window to acquire transmission projection data. The emission contamination detection windows are also scanned axially concurrently with, but offset from, the transmission detection windows to acquire emission data.

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 dual-purpose transmission source for use in a nuclear medicine imaging system is described. A Cs-137 point source is used to transmit radiation having a 662 keV photopeak to a corresponding detector during a transmission scan of an object. The Cs-137 source can be used in transmission scans for correcting either coincidence or single-photon emission data for non-uniform attenuation. When performing a transmission scan to correct single-photon emission data, a collimator may remain mounted to the detector, since a substantial portion of the transmitted radiation completely penetrates the radiation-absorbing material of the collimator to reach the detector.

Abstract: A method of correcting for deadtime and for emission contamination of a transmission scan in a nuclear camera system is provided. The transmission scan is used to correct positron emission tomography (PET) images for attenuation. The camera system includes two detectors and two corresponding single-photon point sources that are collimated to produce fanbeam illumination profiles. A transmission detection window and an emission contamination detection window is defined on each detector. Radiation from each source is scanned axially across the field of view of the corresponding detector in synchronization with the corresponding transmission detection window to acquire transmission projection data. The emission contamination detection windows are also scanned axially concurrently with, but offset from, the transmission detection windows to acquire emission data.

Abstract: A method of correcting for deadtime in an attenuation map generated by a nuclear medicine imaging system is provided. The imaging system includes a gamma ray detector that is rotatable about an object to be imaged. A region is defined on the imaging surface of the detector, such as the edge of the field of view of the detector, such that during a transmission scan of the object, the radiation shadow of the object is substantially less likely to fall upon the defined region than upon other regions of the imaging surface. A blank transmission scan is then performed, including recording the radiation intensity level detected in the region as a reference intensity level. A transmission scan of the object is then performed to acquire an attenuation map of the object, including recording a radiation intensity level detected in the first region during the transmission scan.

Abstract: A method of acquiring transmission self-contamination data for correcting transmission scan data in a nuclear camera system including two transmission radiation sources and two scintillation detectors. A first source is for transmitting radiation to only a first detector and a second source is for transmitting radiation to only a second detector during a transmission scan of an object to be imaged. To acquire the calibration data, radiation is transmitted from the second source to the second detector while the first source is maintained in a non-transmitting state. While the second source is transmitting, the first detector is used to detect the radiation transmitted from the second source. A set of self-contamination data is then generated based on the radiation from the second source detected with the first detector. The calibration data is used to correct a subsequent transmission scan of the object by subtracting the self-contamination data from the transmission scan data.

Abstract: A nuclear camera system includes a pair of detectors orientated 180 degrees apart about an axis of rotation for detecting radiation emitted from an object, a pair of single-photon radiation point sources for transmitting radiation through the object, each to a different detector, and a gantry supporting the detectors and the radiation sources. The gantry provides rotation of the detectors and the radiation source about the axis of rotation, such that the angular positions of the radiation source about the axis of rotation remain fixed relative to the angular positions of the detectors. The camera system further includes a processing system coupled to control the dectors and the radiation sources and to selectably configure the detectors for either coincidence or single-photon emission imaging.

Abstract: The present invention provides an apparatus and method for enhancing the resolution of a Positron Emission Tomography (PET) image in a Nuclear Camera System that is configurable to performs both PET and SPECT imaging. The apparatus includes a crystal that interacts with a gamma ray to create a scintillation event within the surface of the crystal. The gamma rays that impinge the crystal have an incident angle that is limited by a field of view of the crystal. Positioned behind the crystal is a detector that responds to the light photons released by the scintillation event and registers a coordinate value of the scintillation event. Coupled to the detector is a resolution enhancer that generates an in-crystal plane displacement correction value for the coordinate value registered by the detector. The in-crystal plane displacement correction value is then combined with the coordinate value to compute the actual entry point of the gamma ray into the crystal.

Abstract: A dual head nuclear camera system automatically switchable (and optimized) to perform either SPECT imaging or PET imaging that utilizes attenuation correction for nonuniform attenuation in SPECT or PET modes. The dual head detectors contain switchable triggering circuitry so that coincidence detection for PET imaging and non-coincidence detection for SPECT imaging is available. The system uses a variable integration technique with programmable integration interval; variable sized clusters for centroiding, use of dual integrators per PMT channel, the event detection and acquisition circuitry of the camera system is switchable for PET and SPECT imaging. In such a switchable SPECT/Pet dual head camera system, a mechanism and method is shown to perform transmission and emission scanning sessions with two line sources and two detectors wherein two sliding transmission detection windows are employed to differentiate between transmission and emission photons.

Abstract: A multi-detector head nuclear camera system automatically switchable (and optimized) to perform either SPECT imaging or PET imaging. The camera system employs, in one embodiment, multi-detector configuration having dual head scintillation detectors but can be implemented with more than two detector heads. The detectors contain switchable triggering circuitry so that coincidence detection for PET imaging and non-coincidence detection for SPECT imaging is available. Using a variable integration technique with programmable integration interval, the event detection and acquisition circuitry of the camera system is switchable to detect events of different energy distribution and count rate which are optimized for PET and SPECT imaging. The system also includes dual integrators on each scintillation detector channel for collecting more than one event per detector at a time for PET or SPECT mode.