Abstract: A positron CT scanner includes a plurality of detectors arranged in a generally cylindrical multi-layers of rings, and slice septa for restricting visual fields of the detectors so that the visual fields intersect a set axis. An interval of the slice septa is substantially corresponds to a plural number of detector cells each of which can determine positions of .gamma. rays incident in the direction of the set axis. The slice septa are movable relatively to the detector cells in the direction of the set axis during a .gamma. ray counting operation.

Abstract: A data correcting device is intended to be used with a CT apparatus for obtaining a tomographic image with a subject holding means being adapted to be slidable into or out of the tunnel in a gantry. The device includes a body movement sensor for detecting a movement of a subject under examination; a body movement data processing unit for converting body movement data from the body movement sensor into address correcting data; a tomographic data processing unit for processing tomographic data obtained in the gantry; an address converting unit for correcting the address of the tomographic data with the address correcting data; and a memory for storing data.

Abstract: A method and an apparatus for performing address transformation of projection data for use in a positron CT system, where plural detectors are classified into plural detector groups. In this system, a polar coordinate of the addresses assigned to paired detectors which detect coincident events of gamma-ray emission is determined by adding a first encoded signal representing a first polar coordinate of the line joining the reference points of the paired detector groups including the paired detectors and a second encoded signal representing a second polar coordinate of the deviation of the line joining the two detectors from the line joining the reference points. The second encoded signal is obtained on the basis of address signals representing the addresses of the two detectors and a third encoded signal representing the angle relationship of the paired detector groups which is preliminarily stored in a memory.

Abstract: A scintillation detector for three-dimensionally measuring the absorption position of the gamma-rays entering the detector and a positron computed tomography apparatus employing as a gamma-rays detector plural scintillation detectors arranged in the form of a ring are provided which can prevent the degradation of the spatial resolution in the peripheral region of the visual field and uniformly detect a positron distribution over the entire visual field with high resolution. The scintillation detector comprises a bundle of pillar-shaped scintillator elements and position detecting photodetectors coupled to the end surfaces of each scintillator element, and the apparatus comprises a plurality of scintillation detectors formed in a ring, each of which includes a bundle of scintillator elements, and plural position detecting photodetectors each of which is connected to both ends of the scintillator bundle.

Abstract: An improved insulating plate for an insulated rail joint includes a main plate portion made of a thermo-plastic resin, thick portions formed on the main plate portion at its side face contacting a joint plate, and planar heater elements embedded in the thick portions.

Abstract: A pad comprising at least one sheet of material having a thermoplastic resinous composition and a heater actuable to heat and soften the sheet, the pad being for use in alignment of machine equipment, rails, beams, girders, or other constructional elements relative to a horizontal base, vertical or inclined line, or to other constructional elements. In use the pad is placed between the equipment, rail or the like and a support or abutment therefor, and the heater is actuated so as to soften the pad just sufficiently that the weight of object or a force thereon reduces the thickness of the pad an amount equal to the desired movement of the object necessary to achieve the desired alignment.