Abstract: Systems and methods are described for a positron emission tomography camera with individually rotatable detector modules and/or individually movable shielding sections. An apparatus, includes a detector ring including a plurality of individually movable detector modules. Another apparatus, includes a radiation shield including a plurality of individually moveable shield sections. A method, includes generating an emission image of a sample; generating a transmission image of said sample while generating said emission image of said sample; and then correcting said emission image with said transmission image.

Abstract: Methods and apparatuses for obtaining position and energy information without pileup. Signal integration, which is triggered by a present event, stops when a subsequent event is detected. A weighted value for estimating the total energy in a scintillation is calculated, which includes the energy of the current event and a residual energy from previous events. Remnant correction is used to calculate a pile-up free energy from two consecutive weighted values. An analog filter may be applied to reduce noise. Dynamic digital weighting of integrated values, and/or digital integration may be used during data processing. Pileup can be avoided in conjunction with several types of applications, including multi-zone detector applications and coincidence detection applications. High-resolution timing techniques are also disclosed that facilitate one's ability to avoid pileup.

Abstract: Systems and methods are described for asymmetrically placed cross-coupled scintillation crystals. A method includes coupling a plurality of photomultiplier tubes to a scintillation crystal array, the scintillation crystal array defining a plurality of corner edges, wherein a first corner edge of the plurality of corner edges is aligned with a first center of a first photomultiplier tube of the plurality of photomultiplier tubes and a second corner edge of the plurality of corner edges is not aligned with a second center of a second photomultiplier tube of the plurality of photomultiplier tubes.

Abstract: Systems and methods are described for a production method for making position-sensitive radiation detector arrays. A method includes applying a plurality of masks to a plurality of scintillation crystal slabs; coupling the plurality of scintillation crystal slabs to form a sandwich structure; cutting a plurality of slices from the sandwich structure; and coupling at least two of the plurality of slices to form a detector array.

Abstract: Gamma cameras and positron (PET) cameras use scintillation detectors to detect radiation from the body. However, when the number of radiation particles that strike the detector is very high, the chance that signals from two or more individual particles will pile up in the detector (to produce one erroneous, larger signal) is high. This problem is common to all applications using scintillation detectors. The present invention discloses methods and apparatus to prevent and correct for this problem. Results from a circuit according to the present invention show at least a 10 fold improvement in the maximum detection-rate limit over the conventional method.

Abstract: Systems and methods are described for a positron emission tomography camera with individually rotatable detector modules and/or individually movable shielding sections. An apparatus, includes a detector ring including a plurality of individually movable detector modules. Another apparatus, includes a radiation shield including a plurality of individually moveable shield sections. A method, includes generating an emission image of a sample; generating a transmission image of said sample while generating said emission image of said sample; and then correcting said emission image with said transmission image.

Abstract: Gamma cameras and positron (PET) cameras use scintillation detectors to detect radiation from the body. However, when the number of radiation particles that strike the detector is very high, the chance that signals from two or more individual particles will pile up in the detector (to produce one erroneous, larger signal) is high. This problem is common to all applications using scintillation detectors. The present invention discloses methods and apparatus to prevent and correct for this problem. Results from a circuit according to the present invention show at least a 10 fold improvement in the maximum detection-rate limit over the conventional method.

Abstract: Gamma cameras and positron (PET) cameras use scintillation detectors to detect radiation from the body. However, when the number of radiation particles that strike the detector is very high, the chance that signals from two or more individual particles will pile up in the detector (to produce one erroneous, larger signal) is high. This problem is common to all applications using scintillation detectors. The present invention discloses methods and apparatus to prevent and correct for this problem. Results from a circuit according to the present invention show at least a 10 fold improvement in the maximum detection-rate limit over the conventional method.

Abstract: A PET camera is disclosed with radially translating detector segments coupled with a rotational motion to tailor the camera detector ring to the size of the subject for optimal detection efficiency. In particular methods of using the present invention, the detector segments may be radially translated to describe a small diameter in imaging a small object, such as a breast. Alternately, the detectors may comprise a large diameter to image a large object, such as body. The detector segments may be diametrically opposed for optimal positron detection. The present invention may be coupled with a quadrant-sharing-photomultiplier-detector design.

Abstract: A positron emission tomography camera is provided having an array of scintillation crystals placed adjacent other arrays to form an arcuate detection surface surrounding a patient area. Alternatively, the arrays may be placed in a planar configuration on opposing sides of the patient area. Either a three-dimensional image or a two-dimensional image can be formed from a patient's body placed within the patient area. Moreover, the edges between the arrays of crystals are offset in relation to the edges between the light detectors, allowing use of circular photomultiplier tubes instead of the more expensive square photomultiplier tubes. Each light detector is suitably positioned adjacent four adjacent quadrants of four respective arrays to detect radiation emitted from the four quadrants of each array.

Abstract: The invention relates to methods and apparatus for cameras for gamma radiation, including cameras for positron emission tomography (PET). Included in the invention are cameras having radiation detector arrays splittable into sections, which then may be used to extend the axial field-of-view in a two-dimensional mode. Individual array sections may be equipped with collimators. Additionally, splittable PET cameras having detector arrays approximately one-fourth the diameter of conventional whole-body PET cameras are disclosed as having insertable conformal collimators comprising stacks of planar rings. The inner contours of the planar rings are adapted to accept objects to be imaged in the camera and to closely conform to the objects'surface contours.

Abstract: A positron emission topography camera is provided having an array of scintillation crystals placed adjacent other arrays to form an arcuate detection surface surrounding a patient area. Alternatively, the arrays may be placed in a planar configuration on opposing sides of the patient area. Either a three-dimensional image or a two-dimensional image can be formed from a patient's body placed within the patient area. Moreover, the edges between the arrays of crystals are offset in relation to the edges between the light detectors. Each light detector is suitably positioned adjacent four adjacent quadrants of four respective arrays to simultaneously detect radiation emitted from the four quadrants of each array. Moreover, each crystal within the array is selectively polished and selectively bonded to adjacent crystals to present a cross-coupled interface which can tunably distribute light to adjacent light detectors.

Abstract: A time-piece in the form of a wrist-watch which comprises a casing including a dial and a side wall in which a slot is formed, hour and minute hands, drive means located within the casing and supporting the hands on the dial for rotating the hands relative to the dial to indicate time, and a manual operating member located substantially within the casing for rotating the hands relative to the dial by rotation with the hands about corresponding substantially parallel axes. The operating member has a peripheral edge portion of which only a limited region is exposed through the slot in the side wall of the casing, and is movable between an operative position for rotating the hands and an inoperative position not acting upon the hands. A spring is located within the casing and resiliently biasses the operating member towards the inoperative position.

Abstract: A positron emission tomography camera having a plurality of crystals and planes which are positioned side-by-side and form adjacent rows of crystals transverse to the planes. Each row of each plane has a plurality of crystals and a row of light detectors are positioned adjacent each row of crystals. A row of reflecting masks are positioned between each row of crystals and each row of coacting light detectors and coded for providing an identification to the detectors of which crystal detects radiation. In addition, the ends of the crystals have a frosted finish and the sides have a polished finish for increasing the optical efficiency.

Abstract: A PET camera is provided with a modulator of a material having an atomic number of at least 82. The modulator allows uses doses much higher than the PET system can handle by throttling through just the maximum allowable counting rate. As the counting activity delays, the amount of modulation is reduced so that the camera is kept counting near its maximum limit for the scanning period.

Abstract: The method and apparatus of operating a positron emission tomography camera for measuring concentrations of positron emitting radioisotopes which measures radiation from a patient including true counts, scatter counts and random counts through an energy acceptance window in which the camera has a maximum camera transfer capability of measuring counts. The method and apparatus includes measuring the total counts of radiation and varying the energy acceptance window to accept the total counts available at the maximum camera transfer capability thereby minimizing the random and scattered counts and maximizing the true counts. The method further includes injecting an amount of radiation into the patient sufficient to initially saturate the maximum camera transfer capability. The energy acceptance window is varied by the measurement of total counts.

Abstract: A positron emission tomography camera having a plurality of scintillation crystal planes positioned side-by-side around a patient area to detect radiation therefrom and forming adjacent rows of crystals transverse to the planes. Each row of each plane has a plurality of crystals and a row of light detectors are positioned adjacent each row of crystals. A row of slanting light guides are positioned between the crystals and the coacting detectors. The light guides are equal in number to the crystals and have a first end adjacent to one crystal and a second end positioned adjacent the detectors. The second ends of the light guides are axially offset in the rows a different amount from each other for providing an identification to the detectors of which crystal detects radiation.

Abstract: A positron emission tomography camera having a patient area with a plurality of fixed detector rings positioned side-by-side around the patient area to detect radiation. Each ring includes multiple layers of scintillation detectors in which the detectors in one of the layers is offset relative to the detectors in the other layers. The thickness of each layer increases exponentially from the inside of the ring to the outside of the ring. Identification of the scintillation detector may be performed by using layers with different timing constants, using silicon avalanche photodiodes or using a light guide transferring the light received from the staggered detectors to a non-staggered rectangular matrix.

Abstract: A positron emission tomography camera having a patient area with a plurality of fixed detector rings positioned side by side around the patient area to detect radiation. Each ring contains a plurality of scintillation detectors directed toward the patient area for defining a plane slice. Each ring includes multiple layers of scintillation detectors in which the detectors in one of the layers is offset relative to the detectors in the other layers in a ring for increasing the sampling of detected radiation. Photo multipliers for converting detected radiation into electrical pulses are positioned adjacent each ring but offset from the plane of each ring and are directed perpendicularly to the plane of the adjacent ring. The depth of each ring is sufficient to stop gamma radiation but the depth of each layer is less whereby image resolution is improved.