Smv America, Inc.

Summit World Trade Corporation

Gvi Technology Partners, Ltd.

Innovative Imaging Systems, Inc.

Gvi Medical Devices

David S Vickers

William K McCroskey

Christ H Heipp

Geoffrey G Cochrane

William K Mc Croskey

John C Gibbons

William G Greathouse

Robert L Zahn

Roland W Carlson

Christopher H Heipp

Jack A Drobny

A method and apparatus for correcting the output of sensors of a radiation detector by tracking a baseline value detected by the detector during quiescent operation, calculating an average to reduce noise, and storing the average as an offset value for correcting forthcoming data to eliminate the offset.

Method for tracking and correcting the baseline of a radiation detector

A device and method for acquiring Single Photon Emission Computed Tomography (SPECT) data. In particular, a method of acquiring data using a gamma camera detector with a collimator, such as a slotted, inverse fan beam collimator, for example. An example collimator that can be used for the method is one comprising: a slot substantially parallel to the axis of rotation of a SPECT scanner; a plurality of plates, each one of the plates being substantially perpendicular to the slot and also being substantially parallel to a transaxial direction of the SPECT scanner; and a detector associated with the slot and the plurality of plates such that, through any motion of the scanner, the slot, the plates and the detector retain their relative positional relationship.

Collimator for radiation detectors and method of use

A method and apparatus for calibrating the sensors of a radiation detector by collecting a radiation spectrum detected by the detector during an irradiation, calculating a peak energy location from the collected radiation spectrum, determining if the peak energy location is mislocated from a desired location; and adjusting the gain setting for the selected radiation sensor so that the peak energy location is no longer mislocated from the desired location.

Apparatus and method for gain calibration of a radiation detector

A gamma camera is modified to perform PET studies as well as SPECT studies by utilization of the camera's SPECT electronics to likewise generate triggering pulse signals for photons indicative of a positron annihilation event which are corrected, on a bundled basis, for position, linearity and uniformity by the same digital processors used by the camera for SPECT studies. In addition the triggering pulse signals generate analog timing signals passed through a coarse coincidence circuit to establish matched pairs of timing signals which are digitally time stamped and processed along with the bundled set of pulse signals that the timing signals originated from. The timing signals in turn are corrected from a mapped detector head look up table on the basis of the corrected position of the triggering pulse signal and the time lag between each matched timing signal pair passed through a fine coincidence window processor thus insuring that the line of response passing through the corrected, precisely established positions of scintillations that produced the triggering pulse signals occurred within a time period clearly indicative of a positron annihilation event. By counting only true LORs images having high resolution can be constructed even though the camera's detecting heads cover a limited solid angle of event detections. The timing correction table is generated from an improved calibration technique which factors out those inherent time delays, including signal noise and jitter, which are specific to that gamma camera.

Gamma camera for PET and SPECT studies

Gamma camera for pet and spect studies

A gamma camera is equipped with a graded filter plate in lieu of a collimator so that the gamma camera can perform PET studies. The filter plate prevents detection of Compton scattered, positron annihilation photons produced in the patient while permitting detection of photons which have experienced Compton scattering within the camera's scintillation crystal to significantly increase the camera's usable count rate. Additionally, the filter is fitted with a protruding baffle shielding the camera from stray 511 Kev radiation.

Prefilter collimator for PET gamma camera

An automatic calibration system corrects for photomultiplier drift while the gamma camera is in imaging mode. The known constant energy from the gamma rays producing scintillated light is used to effect the drift adjustment by weighting the position signals of the scintillations to determine if a valid event has occurred and building, for each photomultiplier in the camera, a statistically valid, spectral energy histogram. When the histogram counts reach a sufficient sample size the histogram data is read out in a discriminatory manner to account for noise and Compton scattering effects and used to either directly adjust the photomultiplier gain or the calibration look up tables depending on what type of system is used by the camera to process the photomultiplier signals.

Gamma camera with on the fly calibration for PMT drift

An electronic gain control for the photomultipliers of a gamma camera assures that all photomultipliers in the camera have uniform gain for any given gamma event. A specific dynode in the photomultiplier is isolated from the line resistive voltage divider string in the photomultiplier which places each dynode under incremental voltages. A voltage is then applied to the isolated dynode which can vary anywhere from the voltage the isolated dynode would have had if inserted in the voltage divider string to the voltage that the immediately preceding or immediately succeeding dynode in the string has whereby the photomultiplier's gain is controlled. The voltage applied to the isolated dynode is established for each photomultiplier in the camera by individual gain signals developed and stored during calibration of the camera for each radio active isotope whereby all photomultipliers have uniform gain for each isotope.

Gamma camera device

A gamma camera having separate detectors respectively to determine the spatial location and energy of gamma radiation emanating from a patient is disclosed. The preferred camera has two adjacent, mutually perpendicular arrays of parallel, coordinant signal producing scintillaters positioned on the face of a scintillating energy crystal. Each of the fibers within the arrays conducts light resulting from Compton events to an associated one of a set of photodetectors to produce coordinant signals. Other photodetectors monitor the total scintillated energy within the energy crystal. The energy crystal is of sufficient size to absorb energy remaining in each patient emitted gamma ray that has produced Compton events in the coordinant scintillators. The sum of the energies of substantially coincident signals from the fibers and the crystal is used to identify photo peak events.

Gamma camera

A detector arrangement is disclosed for an industrial CT x-ray system which uses a three dimensional cone beam to irradiate the specimen and a large two dimensional scintillation screen to develop a light image corresponding to the energy of the attenuated radiation beams. The light image is focused by a special lens arrangement with zoom capability onto the photocathode of an intensifier. The intensified light image developed is transmitted by fiberoptics to a plurality of CCD chips, each chip developing electrical signals corresponding to a segment of the image developed in the intensifier. The chips are clocked in a predetermined manner based on a prior information developed in an initial scan to produce a high resolution image of large industrial objects in a short time.

Detector imaging arrangement for an industrial CT device

An industrial CT system is provided for three dimensional imaginig which includes a three dimensional cone beam of hard radiation fixed with respect to a two dimensional scintillation detector array. The object is positioned on a turntable interposed between the radition source and detector array. Data from two dimensional views are stored as the object is rotated on the turntable about a fixed axis. The data is sufficient upon completion of one revolution to construct a transparent three dimensional image of the object. A positioning encoding arrangement adjusts for variations in the object's mass density to optimize scan-compute times while enhancing image resolution.

Growing community of inventors

Independence, OH, United States of America

David S Vickers