Abstract: A method of growing a rare-earth oxyorthosilicate crystal, and crystals grown using the method are disclosed. The method includes preparing a melt by melting a first substance including at least one first rare-earth element and providing an atmosphere that includes an inert gas and a gas including oxygen.

Abstract: Disclosed are a method of growing a rare-earth oxyorthosilicate crystal and a crystal grown using the method. A melt is prepared by melting a first substance including at least one rare-earth element and a second substance including at least one element from group 7 of the periodic table. A seed crystal is brought into contact with the surface of the melt and withdrawn to grow the crystal.

Abstract: A Czochralski process (“CZ”) crystal growth method and furnace having a heater capable of generating a heating zone, a crucible within the heating zone and capable of retaining a volume of molten crystal growth material forming a melt line oriented in a designated position within the heating zone, a seed growth rod retractable from the crucible with a rod retraction mechanism, for forming a crystal boule thereon proximal the melt line from the molten crystal growth material. The furnace causes relative movement between the crucible and heating zone as the crystal boule is retracted, so that the melt line is maintained in the designated position within the heating zone. In some embodiments relative movement is based at least in part on sensed weight of the growing crystal boule. In other embodiments the crucible growth rod retraction mechanism are fixed relative to each other by a gantry.

Abstract: A lid for a crystal growth chamber crucible is constructed by forming arcuate sector-shaped portions and coupling them in abutting relationship, for example by welding, to form an annular profile fabricated lid. The arcuate sector-shaped portions may be formed and removed from a lid fabrication blank with less waste than when unitary annular lids are formed and removed from a similarly sized fabrication blank. For example, the sector-shaped portions may be arrayed in an undulating pattern on the fabrication sheet.

Abstract: A method of making LSO scintillators with high light yield and short decay times is disclosed. In one arrangement, the method includes codoping LSO with cerium and another dopant from the IIA or IIB group of the periodic table of elements. The doping levels are chosen to tune the decay time of scintillation pulse within a broader range (between about ˜30 ns up to about ˜50 ns) than reported in the literature, with improved light yield and uniformity. In another arrangement, relative concentrations of dopants are chosen to achieve the desired light yield and decay time while ensuring crystal growth stability.

Abstract: Medical imaging may be accomplished with a high photoconductive gain at a relatively low operating voltage by employing a black silicon photodetector and integrating CMOS components with elements of the photodetector.

Abstract: 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® 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® sheets between each bar (coating the LSO disks and Lumirror® sheets with Epotek 301-2). The glued bar block is then cut again into bars in a perpendicular direction, and these new LSO-Lumirror® bars are etched.

Abstract: 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×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.

Abstract: 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.

Abstract: A method for fabricating a detector or light guide using laser technology. The method yields a detector component such as a scintillator, light guide or optical sensor which provides for the internal manipulation of light waves via the strategic formation of micro-voids to enhance control and collection of scintillation light, allowing for accurate decoding of the impinging radiation. The method uses laser technology to create micro-voids within a target media to optically segment the media. The micro-voids are positioned to define optical boundaries of the optically-segmented portions forming virtual resolution elements within the scintillator. Each micro-void is formed at its selected location using a laser source. The laser source generates and focuses a beam of light into the target media sequentially to form the micro-voids. The laser beam ablates the media at the focal point, thereby yielding the micro-void.

Abstract: 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.

Abstract: 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® 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® sheets between each bar (coating the LSO disks and Lumirror® sheets with Epotek 301-2). The glued bar block is then cut again into bars in a perpendicular direction, and these new LSO-Lumirror® bars are etched.

Abstract: A method of improving the light yield of Oxyorthosilicate scintillation crystals, such as Lutetium Oxyorthosilicate, Yttrium Oxyorthosilicate, Lutetium Gadolinium Oxyorthosilicate or Lutetium Yttrium Oxyorthosilicate scintillation crystals. In accordance with the teachings of the preferred embodiment, the Oxyorthosilicate scintillation crystals are annealed in a atmosphere selected to be a reducing atmosphere or slightly oxidizing at a selected annealing temperature. In this regard, in the preferred embodiment, the Oxyorthosilicate scintillation crystals are heated in a furnace. During the annealing cycle, the temperature is ramped up from room temperature to the annealing temperature over a selected period of time. After a second selected period of time of sustaining the annealing temperature, the annealing temperature is then ramped down over for a selected period of time.

Abstract: 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.

Abstract: A method for precision cutting liquid soluble scintillator materials by an operator is disclosed, including the steps of providing a first run of a moving filament in operative proximity to cut the scintillator materials, concurrent with wetting at least the first run length of the moving filament with organic solvent, and engaging the wetted first run with the soluble scintillator materials for a time sufficient to create a kerf having cut surfaces with solvent thereon, with the kerf cut surfaces dissolved to reshape the kerf corners, and without the formation of surface hydrates. The wetting step is accompanied by providing a second run of the wetted filament in a reverse direction and engaging the scintillator materials. The first run and second run engaging steps are concurrent with tensioning the moving filament, producing kerfs through the scintillator materials, with organic solvent delivered onto kerf surfaces.

Abstract: 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 2×2 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 Si 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;iSi of the four PMT signals Si for pulse shape discrimination. A CFD provides a START signal for the time to pulse height converter.

Abstract: Light guides (1) capable of encoding the transverse and longitudinal coordinates of light emission induced by the interaction of photons in an array of a plurality of the light guides. Each light guide has at least two discrete crystal segments (4) adjacently disposed along a common longitudinal axis of the light guide (1). Between adjacent segments is a boundary layer (7) having less light transmission than the light transmission of the crystal segments (4). A light absorbing mask (8) increases light adsorption in a segment (4). Photons enter the light guide (1) and cause the emission of scintillation light which is delivered in different and resolvable quantities to light sensing devices. The differences in quantity of delivered light is caused by successive decreases in light in part by the boundary layers (7). The differences in quantity of light establish the segment from which the light emission took place.

Abstract: A method of calibrating multi-crystal, single block radiation detectors for use in positron emission tomography and other devices with multi-crystal, single block radiation detectors that are used to determine gamma ray distribution. The detector units are individually subjected to a gamma ray flood source wherein the gamma ray has an energy in excess of about 0.7 MeV, and preferably above about 1.0 MeV. Energies of up to about 10 MeV are usable with the calibration method, with higher energies giving rise to containment and handling problems because of the energy. The light produced within each of the crystals is converted to electrical signals through, for example, photomultiplier tubes. These signals are used to generate a lookup map, this map providing information as to the correct positioning and response of each crystal in the array of crystals of the block detector. The method is useful for detector blocks of of many sizes that are divided into arrays of a large number of crystals.