Abstract: Gain values of PMTs of a PET scanner's detectors are balanced based on detected radiation from a radioactive calibration source placed in an FOV of the scanner. A time alignment is performed for scintillator crystals of the detectors based on TOF computations based on gamma photons associated with the radioactive calibration source. Baseline data is acquired using intrinsic background radiation of the scintillator crystals, without any object in the FOV. A first set of data, based on the baseline data, is stored in a memory of the scanner. After the acquisition of the baseline data, test data is acquired using intrinsic background radiation of the scintillator crystals, without any object in the FOV. A calibration status of the scanner or of an environment surrounding the scanner is automatically checked based on a comparison between the stored first set of data and a second set of data.

Abstract: Gain values of PMTs of a PET scanner's detectors are balanced based on detected radiation from a radioactive calibration source placed in an FOV of the scanner. A time alignment is performed for scintillator crystals of the detectors based on TOF computations based on gamma photons associated with the radioactive calibration source. Baseline data is acquired using intrinsic background radiation of the scintillator crystals, without any object in the FOV. A first set of data, based on the baseline data, is stored in a memory of the scanner. After the acquisition of the baseline data, test data is acquired using intrinsic background radiation of the scintillator crystals, without any object in the FOV. A calibration status of the scanner or of an environment surrounding the scanner is automatically checked based on a comparison between the stored first set of data and a second set of data.

Abstract: Using standard or “off the shelf” cable to interconnect between the PET block detector and the detector circuit may save substantial costs given the number of PMTs in a PET system. Given space constraints, simple maintenance with reduced risk of disturbing cabling is desired, making ongoing use of standard cabling without adding further cabling desired. To implement digital gain control, a further communication is provided between the PET detector block and the detector circuit. Since the standard cable may not have additional wires for such communications and to reduce timing degradation, the PMT signals are combined, such as generating position and energy signals at the PET detector block. The four PMT signals are reduced to three signals without reduction in function, allowing a fourth twisted pair of wires in a CAT5 cable to be used for digital gain control.

Abstract: Using standard or “off the shelf” cable to interconnect between the PET block detector and the detector circuit may save substantial costs given the number of PMTs in a PET system. Given space constraints, simple maintenance with reduced risk of disturbing cabling is desired, making ongoing use of standard cabling without adding further cabling desired. To implement digital gain control, a further communication is provided between the PET detector block and the detector circuit. Since the standard cable may not have additional wires for such communications and to reduce timing degradation, the PMT signals are combined, such as generating position and energy signals at the PET detector block. The four PMT signals are reduced to three signals without reduction in function, allowing a fourth twisted pair of wires in a CAT5 cable to be used for digital gain control.

Abstract: A method and apparatus for determining and correcting the baseline of a continuously sampled signal for use in positron emission tomography. The method employs continuous signal sampling to determine the signal level at time t(0) so that an accurate determination of an integrated signal may be calculated, resulting in an accurate energy estimate for an ac-coupled, continuously-sampled signal at various count rates. The device includes a front-end electronics processing channel including primarily an analog CMOS ASIC, a bank of ADCs, an FPGA-based digital sequencer, and two RAMs. The processing electronics perform continuous digital integration of PMT signals to obtain normalized position and energy. Continuous baseline restoration (BLR) is used, wherein the baseline of the signal pulses are placed at mid-scale by continuously sampling the ADC, thus always making available the past history. A correction signal is generated for use in negative feedback control of the baseline.

Abstract: A method and apparatus for determining and correcting the baseline of a continuously sampled signal for use in positron emission tomography. The method employs continuous signal sampling to determine the signal level at time t(0) so that an accurate determination of an integrated signal may be calculated, resulting in an accurate energy estimate for an ac-coupled, continuously-sampled signal at various count rates. The device includes a front-end electronics processing channel including primarily an analog CMOS ASIC, a bank of ADCs, an FPGA-based digital sequencer, and two RAMs. The processing electronics perform continuous digital integration of PMT signals to obtain normalized position and energy. Continuous baseline restoration (BLR) is used, wherein the baseline of the signal pulses are placed at mid-scale by continuously sampling the ADC, thus always making available the past history. A correction signal is generated for use in negative feedback control of the baseline.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An electrical connector mounting apparatus has an electrically conductive member formed with spring biased fingers, a base portion and a fastening member. The spring biased fingers in conjunction with the base portion provide electrical continuity between the base of the electrical connector and a chassis frame when the connector is inserted into a frame opening. The base portion of the electrically conductive member is captured between the base of the electrical connector and a support member, which prevent excessive connector rotation and provides strain relief between the base portion and the fastening member. The fastening member is spring biased and engages the frame opening during the insertion of the electrical connector into the frame.

Abstract: A high-speed, high-current making switch is provided which has a driver which forms an air cylinder in the housing and which has movable contacts attached thereto. The driver moves the contacts to make and break the circuit. The force to move the driver is provided by pressurized air within the housing chamber which in response to the operation of a solenoid which operates a latch allows the contacts to make very rapidly. Upon operation of the solenoid, the latch is removed from abutting contact with the driver thereby allowing the driver to move in response to the air pressure and make the circuit.

Abstract: A magnetic structure is provided for calibrating a circuit breaker. The magnetic structure includes an E-shaped core which has an adjustable center post for varying the magnetic force between the core and armature by changing the gap between the center post and the armature. Variations in the field for a given current allow the tripping current for the circuit breaker to be precisely calibrated.

Abstract: A book holder for comfortably and securely supporting a book with one hand without the aid of an inanimate support platform such as a table and to aid in the carrying of the book. The book holder has a handle means in connection with elastic bands that attach to the ends of the book. Bookmarking strands may be combined with the book holder to mark the user's place.

Abstract: A ringless-type socket for a watt hour meter is provided with support means to which an insulating carrier for plug-in contacts is mounted. The support means at its forward end is provided with seat means which limits rearward movement of a meter mounted to the socket. Also mounted on this support means are spring retainers for holding the meter in operative position on the seat means. The retainer means is deflectable so that holding means thereof is selectively releasable from holding engagement with the meter to permit removal of the latter.