Abstract: A medium area (S) filled with liquid xenon (2) is formed between an external cylindrical body (1a) and internal cylindrical body (1b), and a pair of anode pads (11, 12) are disposed in two-dimensional form in opposite end portions of the medium area (S) in the intersection direction with respect to the gamma-ray incident direction. An intermediate electrode (10) is disposed between a pair of anode pads (11, 12), and a plurality of photomultiplier tubes (5) is installed in two-dimensional form in the external cylindrical body (1a). Then, the gamma-ray reaction point within the liquid area (S) is identified from signals output from the anode pads (11, 12) and photomultiplier tubes (5).

Abstract: A medium area (S) filled with liquid xenon (2) is formed between an external cylindrical body (1a) and internal cylindrical body (1b), and a pair of anode pads (11, 12) are disposed in two-dimensional form in opposite end portions of the medium area (S) in the intersection direction with respect to the gamma-ray incident direction. An intermediate electrode (10) is disposed between a pair of anode pads (11, 12), and a plurality of photomultiplier tubes (5) is installed in two-dimensional form in the external cylindrical body (1a). Then, the gamma-ray reaction point within the liquid area (S) is identified from signals output from the anode pads (11, 12) and photomultiplier tubes (5).

Abstract: A plurality of input signals are applied to input terminals of first and second priority encoders according to the order of priority in ascending and descending orders, respectively. The encoded output signals of the first and second priority encoders are exclusive-ORed for each corresponding pair of significant bits. A single event detection is executed only if exclusive OR is effected for all the corresponding pairs of significant bits.

Abstract: An apparatus for effecting positron emission computed tomography comprises rows of a plurality of arrays of detectors arranged rotatably around a center of rotation in such way that at least one of the detectors in each array is disposed at an irregular position relative to the rest of detectors in the array, and that, for each revolution of the row through an angle of 360.degree./n (wherein: n represents an odd number of 3 or larger), each array of detectors will assume exactly the position occupied by its adjacent array till the revolution takes place.

Abstract: An apparatus for optically transmitting signals from a rotatable body to a stationary side or vice versa in a non-contact manner, includes a plurality of light emitting elements excited by a PCM signal from a signal source and a plurality of light receiving elements disposed in opposition with the light emitting elements for receiving light therefrom. A plurality of sets each including plural light receiving or emitting elements are provided at the stationary side in association with the respective light emitting or receiving elements disposed at the rotatable body side. Alternatively, a plurality of sets each including plural light emitting elements are provided at the rotatable body side in association with the respective light receiving elements disposed at the stationary side. The elements in such plural sets are selected in accordance with the rotation of the rotatable body.

Abstract: A scanner for positron emission computed tomography comprising a rotary member rotatable within the plane of a slice about an axis lying perpendicular to this plane and having means for accommodating a subject for examination, a drive means for rotating this rotary member within the plane of slice, and a plurality of radiation detectors provided on the rotary member so as to substantially face each other relative to the subject to be examined, in which the radiation detectors are disposed so that at least some of them are either positioned with irregular spacing relative to each other, or positioned at irregular distances from the axis of rotation.

Abstract: A scintillation type radiation-measuring apparatus comprising a radiation-detecting scintillator, wherein a scintillation given off from the scintillator is converted into current by a photomultiplier tube; a current amplifier generates a plurality of pulses each proportional to the intensity of said converted current; the pulses have the width clipped by a clipped pulse generating circuit; the clipped form of the pulses is delayed by a delay circuit and integrated by an integrator; the wave height value of the outputs from the integrator is sampled by a sampling circuit to provide a sampled output; and means are provided to supply instructions to start and reset the operation of the integrator and to commence the operation of the sampling circuit in accordance with the interval between successively detected current pulses.