Abstract: A time-of-flight PET nuclear imaging device (A) includes radiation detectors (20, 22, 24), electronic circuits (26, 28, 30, 32) for processing output signals from each of detectors (20), a coincidence detector (34), a time-of-flight calculator (38) and image processing circuitry (40). A calibration system (48) includes an energy source (50, 150) which generates an electrical or optical calibration pulse. The electrical calibration pulse is applied at an input to the electronics at an output of the detector and the optical calibration pulse is applied to a preselected point adjacent a face of each optical sensor (20) of the detectors. A calibration processor (52) measures the time differences between the generation of the calibration pulse and the receipt of a trigger signal from the electronic circuitry by the coincidence detector (34) and adjusts adjustable delay circuits (44, 46) to minimize these time differences.

Abstract: A radiographic imaging system (10) includes an array of detectors (16) arranged around a circular bore (18). A subject (14) is injected with a radioisotope. The subject (14), supported by a subject support means (12), is to be placed into the bore (18) for an examination. A fixed, non-circular shield (38) is rigidly mounted to one of an entrance (40) and an exit (42) of the bore (18) to prevent emission radiation originating outside of the bore (18) to reach the radiation detectors (16). The shield (38) extends from an outer periphery of the bore (18) toward and surrounding a central axis of the bore (18) and defines a fixed, non-circular subject receiving aperture (36). The shield (38) is tailored to a contour of the subject support and the subject (14) to permit the subject of a maximum girth to be received in the fixed, non-circular aperture (36).

Abstract: A time-of-flight PET nuclear imaging device (A) includes radiation detectors (20, 22, 24), electronic circuits (26, 28, 30, 32) for processing output signals from each of detectors (20), a coincidence detector (34), a time-of-flight calculator (38) and image processing circuitry (40). A calibration system (48) includes an energy source (50, 150) which generates an electrical or optical calibration pulse. The electrical calibration pulse is applied at an input to the electronics at an output of the detector and the optical calibration pulse is applied to a preselected point adjacent a face of each optical sensor (20) of the detectors. A calibration processor (52) measures the time differences between the generation of the calibration pulse and the receipt of a trigger signal from the electronic circuitry by the coincidence detector (34) and adjusts adjustable delay circuits (44, 46) to minimize these time differences.

Abstract: A radiographic imaging system (10) includes an array of detectors (16) arranged around a circular bore (18). A subject (14) is injected with a radioisotope. The subject (14), supported by a subject support means (12), is to be placed into the bore (18) for an examination. A fixed, non-circular shield (38) is rigidly mounted to one of an entrance (40) and an exit (42) of the bore (18) to prevent emission radiation originating outside of the bore (18) to reach the radiation detectors (16). The shield (38) extends from an outer periphery of the bore (18) toward and surrounding a central axis of the bore (18) and defines a fixed, non-circular subject receiving aperture (36). The shield (38) is tailored to a contour of the subject support means (12) and the subject (14) to permit the subject of a maximum girth to be received in the fixed, non-circular aperture (36).

Abstract: A method of generating a filter (40) for a nuclear medicine system (20) where the filter selects valid detected radiation events for image processing. A dataset (60) is provided that is indicative of a plurality of emitted radiation events occurring over a predetermined period of time. Signals representative of the response of a detector to the dataset of the plurality of emitted radiation events are generated. A pattern is determined (66) based on a correlation of a plurality of signals resulting from the response of the detector to a plurality of single radiation events in the dataset. A filter is generated (74) based on the correlation pattern. A method and apparatus of using the generated filter is also disclosed.

Abstract: In the present invention, a tomographic emission scanner has a detection chamber with an axial center line and an axial periphery, and a plurality of single element emission detector units are positioned around the axial periphery of the detection chamber. Each detector unit includes a single detecting element having a detection face oriented toward the detection chamber. The detection face of each detecting element is curved along the axial periphery of the detection chamber.

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: A gamma camera PMT channel amplification integration circuit having multiple separate and independently triggerable integrators. A multiple number (e.g., two) of separate integrators are placed on each PMT channel for independently integrating separate gamma events. By providing multiple separate integrators per channel, problems associated with pulse pile up are reduced since the system can simultaneously integrate with respect to multiple (e.g., two) gamma events. The farther apart spatially the event occurs, the more accurate the resulting integration becomes. The dual integrators are coupled to supply their integration results to a two stage series connected latch circuit. On a first trigger, a first available integrator is reset and at the end of integration, the result is placed into the first stage latch. If a second trigger occurs before the completion of the first integration, then the second integrator, if available, is triggered (e.g., initialized, reset, etc.