Cti Pet Systems, Inc.

Other

Siemens Medical Solutions USA, Inc.

Cti, Inc.

Cit Pet Systems, Inc.

J Clifton Moyers

Ronald Nutt

Mark S Andreaco

William F Jones

Charles W Williams

John W Young

Keith Vaigneur

Michael E Casey

Charles C Watson

Mark Musrock

Keith Valgneur

A method for producing a high resolution detector array so as to provide very high packing fraction, i.e., the distance between scintillator elements is minimized so the detector efficiency will be higher than is currently achievable. In the preferred embodiment of the present invention, the fabrication methodology is enhanced by handling LSO bars rather than single crystals when gluing on the Lumirror&#xae; as well as etching the LSO. Namely, an LSO boule is cut into wide bars of a selected dimension, for example 30 mm, which are then acid etched or mechanically polished. A selected number, N, of these LSO bars can then be glued together with Lumirror&#xae; sheets between each bar (coating the LSO disks and Lumirror&#xae; sheets with Epotek 301-2). The glued bar block is then cut again into bars in a perpendicular direction, and these new LSO-Lumirror&#xae; bars are etched. Finally, a selected number, M, of these LSO-Lumirror&#xae; bars are glued together with Lumirror&#xae; sheets between each bar; thus creating an etched N&#xd7;M LSO-Lumirror&#xae; array, (where M may or may not be equal to N), without having to handle individual LSO crystals or small Lumirror&#xae; pieces.

Method for producing a high resolution detector array

A method for producing a high resolution detector array so as to provide very high packing fraction, i.e. the distance between scintillator elements is minimized so the detector efficiency will be higher than is currently achievable. In the preferred embodiment of the present invention, the fabrication methodology is enhanced by handling scintillator bars rather than single crystals when gluing on an optical film as well as polishing the scintillator. Namely, a scintillator boule is cut into wide bars of a selected dimension, for example 30 mm, which are then acid etched or mechanically polished. A selected number, N, of these scintillator bars can then be glued together with sheets of optical film between each bar (coating the scintillator disks and optical film with an adhesive of a selected index of refraction). The glued bar block is then cut again into bars in a perpendicular direction, and these new scintillator-optical film bars are polished. Finally, a selected number, M, of these scintillator-optical film bars are glued together with sheets of optical film between each bar; thus creating a polished N&#xd7;M scintillator-optical film array, (where M may or may not be equal to N), without having to handle individual scintillator crystals or small pieces of optical film.

A method for producing a high resolution detector array so as to provide very high packing fraction, i.e. the distance between scintillator elements is minimized so the detector efficiency will be higher than is currently achievable. In the preferred embodiment of the present invention, the fabrication methodology is enhanced by handling LSO bars rather than single crystals when gluing on the Lumirror&reg; as well as etching the LSO. Namely, an LSO boule is cut into wide bars of a selected dimension, for example 30 mm, which are then acid etched or mechanically polished. A selected number, N, of these LSO bars can then be glued together with Lumirror&reg; sheets between each bar (coating the LSO disks and Lumirror&reg; sheets with Epotek 301-2). The glued bar block is then cut again into bars in a perpendicular direction, and these new LSO-Lumirror&reg; bars are etched. Finally, a selected number, M, of these LSO-Lumirror&reg; bars are glued together with Lumirror&reg; sheets between each bar; thus creating an etched N&times;M LSO-Lumirror&reg; array, (where M may or may not be equal to N), without having to handle individual LSO crystals or small Lumirror&reg; pieces.

An apparatus and method for determining the total energy of a continuously under-sampled energy signal resulting from an annihilation event detected by a positron emission tomograph (PET) scanner. An annihilation event is detected by a scintillator crystal and photomultiplier tube, which produces an energy signal that is continuously under-sampled by an analog-to-digital converter. The start time of the energy signal is determined by a constant fraction discriminator and time-to-digital converter. The start time is used to calculate a new amplitude for each sample, from which the total energy can be calculated.

Continuous sampling and digital integration for PET scintillation

A coincidence transmission source serves to detect coincident activity from a radiation source. The coincidence transmission source includes a detector dedicated to collecting attenuation data. A collimated radiation source and a detector are positioned with respect to a tomography device such that only a selected strip of the imaging detector of the tomograph is illuminated such that events unrelated to the attenuation are eliminated. The coincidence transmission source includes a collimator in which is disposed a radiation source. An opening is defined by the collimator for exposing a selected portion of the imaging detectors of the tomograph device. Positioned behind the radiation source, relative to the imaging detectors, is the dedicated attenuation detector. The attenuation detector and collimator are designed to illuminate only a strip of the imaging detector, thereby eliminating events not of interest in the attenuation measurement. In a dual head tomograph device, one coincidence transmission source of the present invention is disposed opposite each bank of imaging detectors. The sources and the associated collimators are positioned to the side of each head at a slight angle relative to the respective head. The sources and detectors are fixed relative to the imaging heads. In order to obtain full coverage of the field of view (FOV) in the same manner as for an emission scan, the heads and sources are rotated about the center of the camera.

Coincidence transmission source

A system and method of reducing pile-up errors in multi-crystal tomography applications. In a system with multi-crystal gamma ray detectors having scintillating crystals with different decay constants, the problem of signal pile-up is avoided by taking energy samples during a fast integration time and stopping the integration process if the sampling indicates that the event occurred in the crystal with the faster decay time, and continuing the integration process if the sampling indicates that the event occurred in the crystal with the slower decay time.

System and method for reducing pile-up errors in multi-crystal gamma ray detector applications

A method and apparatus for producing radioactive transmission measurements to form multi-dimensional attenuation correction data with a point source of radiation, such as required in positron emission tomography applications. This involves the passing of the point source proximate the face of a selected each of the tomograph units for the formation of a 3-D image, or a selected portion of the tomograph units for a 2-D image. As such, attenuation data, transmission data, detector performance data, etc., can be obtained. This point source of radiation, in one embodiment, is rapidly circulated through a conduit that passes across each detector face under the influence of a transport fluid in, for example, an oscillatory motion to achieve a selected radiation field whereby calculation of transmission measurements within a body positioned within the tomograph scanner is achieved. When not being circulated, the radiation source is held within a shield. Circulation of the transport fluid, typically a hydraulic fluid, is typically accomplished using a positive displacement pump. Position sensors are used to monitor the movement of the source in the conduit as well as its position within the shield. Disconnect units permit removal of the radiation source, as contained in the shield, from the system without accessing any other portions of the system. In another embodiment, the point source is a CT device.

Method and apparatus for forming multidimenstional attenuation

A method and apparatus for producing radioactive transmission measurements to form a 2-D or a 3-D image with a point source of radiation, such as required in positron emission tomography applications. This involves the passing of the point source proximate the face of a selected each of the tomograph units for the formation of a 3-D image, or a selected portion of the tomograph units for a 2-D image. As such, attenuation data, transmission data, detector performance data, etc., can be obtained. This point source of radiation is rapidly circulated through a conduit that passes across each detector face under the influence of a transport fluid in, for example, an oscillatory motion to achieve a selected radiation field whereby calculation of transmission measurements within a body positioned within the tomograph scanner is achieved. When not being circulated, the radiation source is held within a shield. Circulation of the transport fluid, typically a hydraulic fluid, is typically accomplished using a positive displacement pump. Position sensors are used to monitor the movement of the source in the conduit as well as its position within the shield. Disconnect units permit removal of the radiation source, as contained in the shield, from the system without accessing any other portions of the system.

Method and apparatus for transmission measurements to form a 2-d or a

A method and apparatus for producing radioactive transmission measurements to form a 3-D image with a point source of radiation, such as required in tomography applications. This involves the passing of the point source proximate the face of each detector of the tomograph units. As such, attenuation data, transmission data, detector performance data, etc., can be obtained. This point source of radiation is rapidly circulated through a conduit that passes across each detector face under the influence of a transport fluid in, for example, an oscillatory motion to achieve a selected radiation field whereby calculation of transmission measurements within a body positioned within the tomograph scanner is achieved. When not being circulated, the radiation source is held within a shield. Circulation of the transport fluid, typically a hydraulic fluid, is typically accomplished using a positive displacement pump. Position sensors are used to monitor the movement of the source in the conduit as well as its position within the shield. Disconnect units permit removal of the radiation source, as contained in the shield, from the system without accessing any other portions of the system. The method and apparatus are illustrated as being applied to a positron emission tomograph units.

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Oak Ridge, TN, United States of America

J Clifton Moyers