Abstract: The invention comprises a system and method for creating medical images of a subject patient using a plurality of imaging devices, such as tomographic imaging scanners. The system comprises a plurality of imaging devices, each having a bore through which a patient is translated during scanning. The bores of each device are substantially aligned axially with respect to each other. An open area is formed between the imaging devices along the path of the patient, through which a caregiver can attain line-of-sight visual contact with or other access to the patient. During a scanning operation, the scanned portion of a patient is transported through the bore of the first device, past the opening between the devices and into the bore of the second device.

Abstract: The invention comprises a system and method for creating medical images of a subject patient using a plurality of imaging devices, such as tomographic imaging scanners. The imaging devices each have a bore through which a patient is translated during scanning. The imaging devices can be moved apart to allow greater access to a patient between the bores.

Abstract: The invention comprises a system and method for creating medical images of a subject patient using a plurality of imaging devices, such as tomographic imaging scanners. The system comprises a plurality of imaging devices, each having a bore through which a patient is translated during scanning. The bores of each device are substantially aligned axially with respect to each other. An open area is formed between the imaging devices along the path of the patient, through which a caregiver can attain line-of-sight visual contact with or other access to the patient. During a scanning operation, the scanned portion of a patient is transported through the bore of the first device, past the opening between the devices and into the bore of the second device.

Abstract: The invention comprises a system and method for creating medical images of a subject patient using a plurality of imaging devices, such as tomographic imaging scanners. The imaging devices each have a bore through which a patient is translated during scanning. The imaging devices can be moved apart to allow greater access to a patient between the bores.

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 attenuation during emission imaging in a gamma camera medical imaging system. Attenuation values are determined empirically and are stored in a look-up table in a memory that is readable by the imaging system, with each attenuation value corresponding to a given thickness value. The attenuation values are computed before imaging is performed by first measuring the number of photons which pass from a transmission source through various known depths of water or another suitable model attenuator, using the same radiation source as will be used for emission imaging. For each depth, the measurement is then used to compute the actual attenuation for a thickness of the model attenuator. The attenuation is then stored as a value in the look-up table with corresponding values of attenuator thickness and is later used to correct emission data for the effects of attenuation.

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: A method of correcting coincidence data for random coincidences in a nuclear medicine imaging system is provided. The system includes a pair of detectors that are rotatable about an axis, with an object to be imaged disposed about the axis. During an imaging session, the detectors detect coincidence radiation emitted from the object at a plurality of angular stops relative to the axis. While rotating the detectors between stops, the detectors are reconfigured for single-photon data acquisition and are used to detect radiation in singles mode. The detected singles are rebinned into a plurality of randoms sinograms, which are used to correct the coincidence data.

Abstract: A method of calibrating an attenuation map for use in emission imaging in a gamma camera system. The attenuation map is generated using a transmission scan of the object of interest. The map includes a number of attenuation coefficients for the object. A computer program for generating the attenuation map includes an instruction for scaling the attenuation coefficients in the map from the transmission energy level to the emission energy level using a scaling factor. The scaling factor includes an effective attenuation coefficient for water, which is determined empirically. To determine the effective attenuation coefficient, the number of photons which pass from a transmission source through known depths of water using the emission energy level is counted. The effective attenuation coefficient is computed based on a standard equation describing the attenuation of photons by an absorber. The scaling factor used by the computer program is then set based on the effective attenuation coefficient.

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 gamma camera for a Positron Emission Tomography (PET) system comprises a single, continvous scintillation crystal having an imaging surface, and a first layer of septa disposed along the imaging surface between the object and the imaging surface. A gap is provided between the imaging surface and the first layer of septa to allow non stray radiation to reach the imaging surface. The septa may be arranged to have a long axis disposed at an acute angle away from perpendicular to an axis of rotation or made to move in relation to the imaging surface of the scintillation crystal to reduce cold spots on the image. Multiple layers of septa may be provided.

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.

Abstract: An automatic collimator exchanger for a gamma camera system for simultaneous exchange of pairs of collimators (or a single collimator) for a dual detector head system. The present invention includes an exchange assembly having an elevator, a carriage and a bridge. The elevator includes a rack of multiple parallel and stacked trays for holding various pairs of collimators. A draw bridge unit is attached to one side of the elevator (which side faces a gantry structure) and may extend into the gantry structure. The carriage is able to support two collimators and moves from within the elevator unit onto the bridge and into the gantry structure, when the bridge is lowered, to position between two aligned detector heads of the dual head gamma camera system. When the detector heads are positioned near the aligned carriage, latch pins are released and collimators may be transferred to the carriage, if empty, or hastened to the detector heads from the carriage when installing a pair of collimators.

Abstract: An automatic gain calibration system for photomultipliers of a scintillation detector operable during periods when a collimator is installed to the scintillation detector. The system provides for calibration of the photomultipliers (PMTs) that are located along the periphery of the detector whose surfaces that are partially or totally obscured by the solid lead edge regions of the installed collimator (e.g., obscured PMTs). In such a manner, the entire scintillation detector may be calibrated effectively without removal of the heavy and awkwardly handled collimator. The automatic calibration system adjusts the preamplification gain associated with each channel of the PMT array to maintain the effective gain of each PMT in response to long term variations in the characteristic gain of each PMT. For calibration, the system measures the response of an obscured PMT to gamma events occurring within a thin strip area that extends into the central portion of the collimator.

Abstract: A system for automatically positioning zoom regions located on imaging surfaces of an ECT camera system during ECT rotation to track relative movement of an object that is located offset from the center of rotation of the ECT camera system. During an ECT scan session, the imaging surfaces of the camera system rotation about an object of interest that is located offset from the center of rotation of the camera system in order to minimize the separation between the imaging surfaces and the object surface. Since the object of interest is offset from the center of rotation, a predetermined zoom region located on the imaging surfaces must alter its position relative to the imaging surface during an ECT scan session in order to remain aligned with the object being imaged. The system determines this alignment position and thereby adjusts, in real-time, the location on the imaging surface of the zoom regions for increased image quality.

Abstract: A direct measurement system for proximity detection of a body profile for use within nuclear medicine. The measurement system includes two or three proximity detector units mounted on a gantry structure of a nuclear medicine camera which each emit an energy beam which is swept across a portion of a target body. Each detector is capable of directly measuring the distance from the proximity detector unit to the target body with a beam sample. The detectors then create a body profile of the target body which is used to minimize the distance between the collimator of a scanning camera and the target body surface thus improving image quality of the scanning camera. There is relative motion between the object and the gantry along a cranial-caudal axis of a target body for scanning successive body profiles. Successive body profiles are combined together to achieve a complete body contour of the target body.

Abstract: A system for automatically positioning zoom regions located on imaging surfaces of an ECT camera system during ECT rotation to track relative movement of an object that is located offset from the center of rotation of the ECT camera system. During an ECT scan session, the imaging surfaces of the camera system rotate about an object of interest that is located offset from the center of rotation of the camera system in order to minimize the separation between the imaging surfaces and the object surface. Since the object of interest is offset from the center of rotation, a predetermined zoom region located on the imaging surfaces must alter its position relative to the imaging surface during an ECT scan session in order remain aligned with the object being imaged. The system determines this alignment position and thereby adjusts, in real-time, the location on the imaging surface of the zoom regions for increased image quality.

Abstract: A method is provided for preparing medicinally acceptable .sup.123 I by bombarding an XI (X is alkali metal or I) target in the liquid phase with a proton beam of a predetermined amperage and energy, while continuously passing a helium stream, optionally having a small amount of xenon, through the target area. The radioactive xenon collected by the helium stream is trapped in a cold trap, purified and then isolated in a deacy vessel, where the xenon decays to .sup.123 I. An iodine scavenger is provided for the helium effluent from the target, to remove any iodine from the helium stream, which would decrease the purity of the desired isotope.

Abstract: An improved image acquisition system allows the angular displacement between two detectors to be adjusted between 90° and 180° to reduce the imaging time for both 360° and 180° scans. A patient table is displaced vertically and horizontally from a lateral axis to allow the body of a patient to be positioned next to the detectors and to improve resolution.

Abstract: An improved image acquisition system allows the angular displacement between two detectors to be adjusted between 90° and 180° to reduce the imaging time for both 360° and 180° scans. A patient table is displaced vertically and horizontally from a lateral axis to allow the body of a patient to be positioned next to the detectors and to improve resolution.