The United States of America as Represented by the Department of Health

Rodney A Brooks

Walter S Friauf

Horace E Cascio

Victor J Sank

Victor Sank

A discriminator circuit for use with a scintillation detector, wherein the scintillation detector output is fed to a time discriminator and the output of the time discriminator is fed via a short precision delay device to one input terminal of a transmission gate device. The detector output signal is also fed to a fast energy discriminator whose output is furnished as an enable signal to the other input terminal of the transmission gate device, providing time output pulses. Timing pulses from the transmission gate device are furnished to a long non-precision delay device and then to one input terminal of a transmission gate. The detector output signal is also fed through a slow energy discriminator and an enable line to another input terminal of the last-named transmission gate, providing energy output pulses in an energy output line which are furnished to the subsequent portion of the system.

Nuclear pulse discriminator

A positron emission tomographic scanner is provided with cross-slice event data handling capability by adding only a coincidence detector and register in common to the circuitry for two adjacent planar detector arrays and adding an OR gate to the circuitry for each array. The improvement permits the same circuitry to be utilized for both cross-slice event processing and intra-slice event processing. Selection of the identification code for a detector is determined by a first coincidence detector in the case of an intra-slice event and the added coincidence detector in the case of an inter-slice event.

Cross-slice data acquisition system for pet scanner

A gamma ray coincidence analysis system for a multichannel nuclear imaging device of the type employing scintillation detectors in ring-like arrays, with the detectors arranged in quadrants of the rings. The scintillation detectors in a ring have output circuits including respective timing discriminators and OR gates, and respective energy discriminators providing delayed energy pulses, and wherein timing pulses from the respective quadrants are fed via the OR gates to the inputs of a four-input coincidence detector without any delay except for a small delay internal to the discriminators and the very small delay of the OR gates. The delay of the energy pulses at the energy discriminators is for an energy validation period of 500 nsec. The output pulse from the coincidence detector is subsequently delayed for a similar period for verification of the energy levels of the two channels causing the coincidence. A data output signal is generated responsive to the concurrence of the delayed coincidence signal and the delayed energy verification pulses.

Gamma ray coincidence analysis system

A dual-energy detector system for use in computer assisted tomography. This system produces two independent sets of information from one scan, namely, high-energy and low-energy data. The system employs two cooperating detectors. The first one responds primarily to low-energy photons, allowing most high-energy photons to pass through. The second detector lies behind the first and detects the remaining photons. Thus, two electrical signals are generated which contain information in two different energy ranges, which signals can be computer-processed. The attenuation coefficients at these two energies are sufficiently different so that differential diagnosis and chemical identification may be aided. The computer-processed signals may be employed to provide any of (a) beam-hardening correction, (b) chemical identification and composition of tissues, such as lesions, bone, etc., (c) localization of injected contrast material, or (d) attenuation coefficients for radiation therapy planning.

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Bethesda, MD, United States of America

Rodney A Brooks