Cti Pet Systems, Inc.

Siemens Medical Solutions Usa, Inc.

Products for Health and Industry

Ortec, Inc.

Cit Pet Systems, Inc.

Charles W Williams

Mark S Andreaco

Ronald Nutt

J Clifton Moyers

Michael E Casey

Matthias J Schmand

Mehmet Aykac

Niraj K Doshi

David T Duncan

Keith Vaigneur

David M Lipscomb

John McElligott

Lars Aldon Eriksson

Keith Valgneur

Kelly Milam

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 detector for use in imaging applications includes at least one detector array, an array of photodetectors, and a continuous light guide disposed between the detectors and the photodetectors. The light guide is continuous over the entire area of the photodetectors and detectors. The thickness of the light guide is optimized based on the shape of the photodetector array. Each detector array includes a plurality of scintillator elements disposed in an M&#xd7;N array, where 'M' and 'N' are independently selectable and are each at least one. A mechanism for maintaining the relative positions of the individual scintillator elements with respect to each other is provided. The retainer is further provided to enhance the separation between the individual detector arrays to define distinct boundaries between the position profiles of the scintillator arrays.

Detector array using a continuous light guide

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 fabricating an array adapted to receive a plurality of scintillators for use in association with an imaging device. The method allows the creation of a detector array such that location of the impingement of radiation upon an individual scintillator detector is accurately determinable. The array incorporates an air gap between all the scintillator elements. Certain scintillators may have varying height reflective light partitions to control the amount of light sharing which occurs between elements. Light transmission is additionally optimized by varying the optical transmission properties of the reflective light partition, such as by varying the thickness and optical density of the light partitions. In certain locations, no light partitions exist, thereby defining an air gap between those elements. The air gap allows a large increase in the packing fraction and therefore the overall sensitivity of the array.

Detector array using internalized light sharing and air coupling

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.

A scintillation detector which includes a plurality of discrete scintillators composed of one or more scintillator materials. The discrete scintillators interact with incident radiation to produce a quantifiable number of photons with characteristic emission wavelength and decay time. A light guide is operatively associated with the scintillation crystals and may be either active or non-active and segmented or non-segmented depending upon the embodiment of the design. Photodetectors are provided to sense and quantify the scintillation light emissions. The process and system embodying various features of the present invention can be utilized in various applications such as SPECT, PET imaging and simultaneous PET systems. In accordance with the present invention, the detector array of the present invention incorporates either a single scintillator layer of discrete scintillators or discrete scintillators composed of two stacked different layers that can be the same scintillator material or of two different scintillator materials. In either case the different layers are composed of materials that have distinctly different decay times. The variants in these figures are the types of optical detectors which are used, i.e. photomultipliers and/or photodiodes, whether or not a segmented optical light guide is used, and whether the light guide is active or non-active. If a segmented optical light guide is used then the variant is whether the configuration is inverted or non-inverted.

Scintillation detector array for encoding the energy, position, and time coordinates of gamma ray interactions

A depth of interaction detector block for improving the spatial resolution and uniformity in modern high resolution PET systems over an entire FOV. An LSO crystal layer, a GSO crystal layer, and a light guide are stacked on each other and mounted on a 2&times;2 PMT set, so that the corners of the phoswich are positioned over the PMT centers. The crystal phoswich is cut into a matrix of discrete crystals. The separation of the LSO and the GSO layers by pulse shape discrimination allows discrete DOI information to be obtained. The block design provides an external light guide used to share the scintillation light in four PMTs. The 4 PMT signals S,are connected to an amplifier box which offers a 4 pole semi-Gaussian shaping for each of the four PMT signals, a sample clock for triggering the ADC cards and a fast sum signal &Sgr;,S,of the four PMT signals S,for pulse shape discrimination. A CFD provides a START signal for the time to pulse height converter. The fast sum signal is in addition differentiated and integrated with a fast filter amplifier and connected to a CFD, which provides a STOP signal for the TAC. The outputs of the shaped PMT signals and the TAC are connected to two ADC cards running under computer control.

Depth of interaction detector block for high resolution positron emission tomography

A rebreather apparatus for negating temporary hearing threshold shifts due to noise exposure and other physiological conditions related to CO.sub.2 concentration. One embodiment of rebreather is formed with three chambers. A mouthpiece communicates with a first chamber and this chamber has limited access to the second chamber sandwiched thereto. A third chamber is sandwiched to the second chamber and has limited communication with the second chamber. The third chamber has limited communication therefrom to the atmosphere thus providing an elongated air pathway from the atmosphere to the mouthpiece. This elongated pathway with the restrictions of the openings between chambers achieves an accumulation of carbon dioxide from a user's breath. Accordingly, air inhaled from the rebreather elevates the carbon dioxide content in the lungs of a user and thus in the blood stream of the user. In another embodiment, the outer (third) chamber is collapsible during nonuse so that the rebreather may be carried in the pocket of the user and the second and third chambers have two portions symmetrically positioned on opposite surfaces of the first chamber. In another embodiment, at least the second and third chambers are collapsible. In a further embodiment, the rebreathing device comprises two collapsible chambers. The device is made from inexpensive materials so that, if desired, it may be disposed of after use.

Carbon dioxide rebreathing apparatus

A rebreather apparatus for negating temporary hearing threshold shifts due to noise exposure and other physiological conditions related to CO.sub.2 concentration. The rebreather is formed with three chambers. A mouthpiece communicates with a first chamber and this chamber has limited access to the second chamber sandwiched thereto. A third chamber is sandwiched to the second chamber and has limited communication with the second chamber. The third chamber has limited communication therefrom to the atmosphere thus providing an elongated air pathway from the atmosphere to the mouthpiece. This elongated pathway with the restrictions of the openings between chambers achieves an accumulation of carbon dioxide from a user's breath. Accordingly, air inhaled from the rebreather elevates the carbon dioxide content in the lungs of a user and thus in the blood stream of the user. This elevated carbon dioxide content has been shown to negate and/or prevent temporary hearing threshold shifts due to excessive noise exposure. In one embodiment the outer (third) chamber is collapsible during nonuse so that the rebreather may be carried in the pocket of the user and the second and third chambers have two portions symetrically positioned on opposite surfaces of the first chamber. In another embodiment at least the second and third chambers are collapsible. The device is made from inexpensive materials so that, if desired, it may be disposed of after use.

In the digital intervalometer disclosed herein, a vernier measurement providing a resolution finer than one clock period is obtained by charging a single capacitor both during the interval between a start signal and a subsequent clock pulse and also during the interval between a clock pulse subsequent to a stop signal and a delayed stop signal. The analog voltage to which the capacitor is charged is converted to a digital value, which digital value is then combined with a clock count accumulated between the stop and start signals to provide a combined digital measurement having a resolution substantially finer than one clock period.

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Powell, TN, United States of America

Charles W Williams