Abstract: An apparatus for automatically correcting image distortions by inter-image processing, which is arranged to obtain, prior to performing the inter-image processing of two two-dimensional digital images, a displacement vector between these two images, and to thereby obtain, based on this displacement vector, a corrected image of one of these two images, and to provide this corrected image for performing the inter-image processing between it and the other image.

Abstract: In a radiation detector having a radiation-stimulated light emitting scintillator and a photodetector for receiving the light emission from the scintillator, the scintillator is formed of a layer of phosphor particles and a light scattering layer is provided in an optical path between the phosphor particle layer and the photodetector. Light generated in the surface of the scintillator is scattered and absorbed by the light scattering layer in some degree so that the reduced quantity of light incident upon the photodetector lowers the output of the photodetector. This effect is balanced with the lowering of the photodetector output due to the absorption and scattering of light generated at the inner parts of the scintillator and further removes anisotropic light emission. As a result, signal-to-noise ratio is greatly improved.A shielding layer between the scintillator and photodetector prevents secondary radiation such as scattered and fluorescent radiation from reaching the photodetector.

Abstract: A radiation-image photographing apparatus comprises a radiation source, a radiation detector disposed in opposition to the radiation source for detecting radiation through an object to be examined and to generate an electrical signal proportional to the amount of incident radiation, a scanning device for changing the relative, positional relationship between the radiation source and the radiation detector, an analog-to-digital converter for converting the output signal from the radiation detector to a digital quantity, a memory for storing the digital signal, an arithmetic unit, and a display unit.

Abstract: A radiation detector comprising a scintillator exhibiting luminescence by the action of radioactive rays and a light detector detecting light output of said scintillator, characterized in that said scintillator is a phosphor represented by the formula:(A.sub.1-x-y Ln.sub.x Ce.sub.y).sub.2 O.sub.2 S:Xwherein A is at least one element selected from the group consisting of Y, La and Gd; Ln is at least one element selected from the group consisting of Pr, Tb and Eu; and X is at least one element selected from the group consisting of F, Cl and Br; and the values of x and y are 0.000003.gtoreq.x.gtoreq.0.2, and 0.000001.gtoreq.y.gtoreq.0.005, and the amount of X is 0 to 1000 ppm on weight basis, has a very short after glow time because of having Ce in the phosphor.

Abstract: A phosphor powder layer is formed by a process comprising a step of mixing a phosphor powder with a polymer emulsion and drying the mixture to give the phosphor powder coated with the polymer and a step of subjecting the phosphor powder coated with the polymer to heating and pressing. The resulting powder layer is suitable as a scintillator used in a radiation detector, particularly in a radiation detector used in X-ray CT.

Abstract: An apparatus for a detecting the location of incident radiation comprises at least one pair of assembly comprised of a scintillation crystal consisting of a plurality of crystal segments, a pair of photo-multiplier tubes optically coupled to the scintillation crystal so as to be able to detect a scintillation produced in any one of these crystal segments. These plural crystal segments are coupled to each other in such manner that any scintillation produced in any single crystal segment will cause the photo-multiplier tubes to deliver substantially a same output irrespective of the illuminating position within this crystal segment, and also that scintillations produced in the respective crystal segments will cause the photo-multiplier tubes to deliver outputs which are different in level for the respective crystal segments.

Abstract: A circuit for exciting an ultrasonic transducer element comprises a diode switch exhibiting a long reverse recovery time duration connected between an input and an output terminal. A transducer exciting signal varying in both positive and negative directions and applied to the input terminal is conducted to the output terminal through the diode switch.

Abstract: In the X-ray CT system, the X-ray detectors vary in output characteristics such as linearity, directivity and radiation quality from one detector to another. To make compensations for such irregularities, a plurality of phantoms of different absorption is prepared in the CT system according to the present invention. Namely, this plurality of phantoms is set one by one in the measuring space in the same manner as in the examination of an examinee or subject to be examined; the coefficient of X-ray absorption is determined for each of these phantoms. Further, theoretical values of absorption for each phantom are compared to the actual absorption measurements on each phantom to provide an absorption error value for each detector at differing absorption levels. The actual subject absorption value for each detector is used to pick the two error values closest to the actual value. The two error values are interpolated or extrapolated to find an error value for correcting the actual absorption value.

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: In an ionization chamber type X-ray detector used in a computerized X-ray tomography device, non-insulative material such as semiconductive or conductive material is provided on each of paired electrode supporting plates for supporting anode and cathode electrodes, whereby the electrification of the electrode supporting plate may be prevented so that a signal current can be exactly and stably detected.

Abstract: A method is disclosed in which projection images of a certain cross-section of an object are produced through irradiation from various directions to the cross-section, and a three-dimensional image of the cross-section is reconstructed from the projection images. A convolution integral operation is performed on the projection images by means of a weighting function obtained from a function whose second differentiation is positive in at least a predetermined range of a spacial frequency domain and which has a positive first-differential coefficient at a point where the spacial frequency is equal to zero.

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: In a radiation detector including a radiation sensitive scintillator and a photo-electric conversion element, a film of silicon nitride providing a modified refractive index is interposed between the scintillator and the photo-electric conversion element.

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 scanning device for use in axial transverse tomographic apparatus, arranged so that a support which carries thereon an X-ray source and its associated detector is mounted on a rotary disk for reciprocating linear movements, and that this rotary disk is caused to rotate through a certain angle at a time for each change of direction of the linear movements of the support. The support is moved at a plurality of different speeds. Either a single or a plurality of damping means are arranged so as to reduce the speed of movement of the support and then to accelerate this speed in association with the movement speed thereof at any changing of direction of movement of this support.

Abstract: The effective area of observation of a scanning-type scintillation camera is expanded relative to the actual area scanned by shifting the position of a spatial window back and forth in the direction of scanning so that the sum of the window velocity and the velocity of actual scanning represents a predetermined scanning velocity.

Abstract: An apparatus for axial transverse tomography using piercing radiation such as X-ray and .gamma.

Abstract: In an ultrasonic imaging system including an array of ultrasonic oscillators, ultrasonic beams are electronically scanned by sequentially selecting a plurality of oscillator sets for beam transmission and reception. For one transmission of ultrasonic waves, at least two receiver oscillator sets having at least some oscillators in common are simultaneously selected, and the respective outputs from the oscillators in the at least two receiver oscillator sets are phase-adjusted so that echoes received by the at least two receiver oscillator sets effectively correspond to echoes substantially emanating from at least two respective different points on a depth level distanced from the plane of the oscillator array by a predetermined depth, whereby at least two signals and hence at least two successive scan lines relating to the echoes from those respective different points are produced. As a result, improved line resolution and rapid line acquisition can be obtained.

Abstract: Disclosed is a method for transmission and reception of ultrasonic beams using an array of ultrasonic transducer elements in which a plurality of transducer element sets each including the selected number of transducer elements for the transmission and/or reception of ultrasonic beams are sequentially selected. First and second sets having different focal axes defined relative to the plane of the transducer array are selected for the transmission and reception modes of operation respectively during the production of a single scan line. The position of at least one of the transducer elements in the first set is different from those of the transducer elements in the second set.

Abstract: In a system in which the tomographic image of an object under investigation is produced on the basis of the amount of absorption of radiation by the object when a source of radiation and a plurality of radiation sensitive detectors with the object interposed therebetween are rotated around the object, the output signal from at least one of the plural detectors is used to correct the radiation absorption amount. Another selected one of the plural detectors may be used for checking whether the object is positioned within a useful detection view.