Abstract: A positron emission detection scanner includes a first plurality of detecting elements arranged in a first two dimensional geometrical array, the detecting elements defining a first detection surface oriented for receiving radiant energy stimulus incident thereto. The detecting elements each have a second surface for communicating light from a scintillation event occurring in response to receiving a radiant energy stimulus. A light transmitting member is provided for receiving light from the scintillation events from each of the detecting elements. A second plurality of light sensing members is arranged in a second two dimensional geometrical array, different from the first geometrical array, the alignment of the light sensing members is independent of the detecting elements.

Abstract: A variable filter arrangement wherein differently sized and shaped filters are automatically selected and installed from a collection of filters housed within a configuration for use with a radiation source. The line source is typically used for transmission scanning to collect attenuation correction factors. A line source is utilized in the preferred embodiment and a series of filters (e.g., differently sized "bow-tie" filters) are rotatably attached to a central junction so that a particular filter can be rotated into an installed position. When installed, the filter acts to attenuate the radiation emitted from the line source to reduce radiation emitted on an otherwise unobstructed area of a scintillation detector. Differently sized filters are advantageously used to accommodate differently sized patents and also to accommodate different unobstructed parts of a detector for different angles of rotation during an ECT transmission scan.

Abstract: A circuit for performing digital dynamic compression wherein the circuit is readily modifiable to accept different compression procedures and the input and output signals are in digital form. The system utilizes a memory unit (e.g., a random access memory or other form of programmable memory, such as EEPROM) to contain a procedure utilized to transform digital input channel signal to an offset digital value which is determined based on the total energy of a gamma interaction. This offset digital value is then subtracted from the digital input channel data to arrive at the output dynamically compressed value. However, given sufficient memory size, the memory circuit may be implemented to directly output the compressed value. Since a programmable memory look up table is utilized to contain the dynamic compression procedure, different dynamic compression procedures may be readily loaded into the memory from a computer system.

Abstract: An automatic collimator exchanger for a gamma camera system for simultaneous exchange of pairs of collimators (or a single collimator) for a dual detector head system. The present invention includes an exchange assembly having an elevator, a carriage and a bridge. The elevator includes a rack of multiple parallel and stacked trays for holding various pairs of collimators. A draw bridge unit is attached to one side of the elevator (which side faces a gantry structure) and may extend into the gantry structure. The carriage is able to support two collimators and moves from within the elevator unit onto the bridge and into the gantry structure, when the bridge is lowered, to position between two aligned detector heads of the dual head gamma camera system. When the detector heads are positioned near the aligned carriage, latch pins are released and collimators may be transferred to the carriage, if empty, or hastened to the detector heads from the carriage when installing a pair of collimators.

Abstract: A system including circuitry within a gamma camera system for generating spatially variant photomultiplier cluster based on a peak photomultiplier and for generating spatially variant weights for photomultipliers of the cluster depending on a cluster type signal. The system includes a first memory circuit addressed by a peak photomultiplier address signal and responsive thereto which generates (1) a unique photomultiplier cluster in geometry and size for the peak photomultiplier and (2) a cluster type. A resolution input signal (high/low) changes the size of the cluster. The first memory is programmable. A second memory responsive to photomultiplier addresses of the cluster and the cluster type, generates weight values for each photomultiplier. The second memory is programmable. The second memory allows weights for individual photomultipliers to be altered based on the geometry and size (e.g., type) of the cluster generated by the first memory.

Abstract: The circuit is adapted for integration of pulse signals of the shape U(t)=U.sub.0 exp(-t/.tau.), wherein the time constant .tau. can be determined in advance by a calibration measurement, in particular signals from a scintillation detector. The purpose is to treat pile-up phenomena, without measuring the integration time, wherein the measured integral is corrupted because the time distance between two pulses becomes smaller than the integration time for the first pulse. The circuit comprises an integrator (4, 5, 6, R, C) for the pulse signal and a summator (3, R.sub.1 -R.sub.3) for forming a weighted sum of the pulse signal (on 1, 2) and the integrated signal (from 4, 5), the weight of the pulse signal and the weight of the integrated signal having such a relation to each other that the result signal (on 8) is proportional to the sum of the time integral of the pulse signal and .tau. times the pulse signal.

Abstract: A direct measurement system for proximity detection of a body profile for use within nuclear medicine. The measurement system includes two or three proximity detector units mounted on a gantry structure of a nuclear medicine camera which each emit an energy beam which is swept across a portion of a target body. Each detector is capable of directly measuring the distance from the proximity detector unit to the target body with a beam sample. The detectors then create a body profile of the target body which is used to minimize the distance between the collimator of a scanning camera and the target body surface thus improving image quality of the scanning camera. There is relative motion between the object and the gantry along a cranial-caudal axis of a target body for scanning successive body profiles. Successive body profiles are combined together to achieve a complete body contour of the target body.

Abstract: An apparatus and method for producing digital video images provides for obtaining a first image (42) and a second image (44), and subtracting the first from the second to obtain a difference image (46). The intensity of the difference image is increased relative to the first image (48). The enhanced difference image is added to the first image (50). The result is an image which emphasizes changes between the first and second images, while preserving enough common background to provide a frame of reference from which to view the changes.