Abstract: The present invention is an imaging method using three-dimensional NMR to which an echo-planar method is applied. After excitation of nuclear spins, the gradient magnetic field Gx for phase-encoding is applied and there is repeated a sequence of measuring and obtaining an echo train of spin-echoes with a constant gradient magnetic field Gx and a periodically-inverted gradient magnetic field Gy, as varying the amount of encoding, so as to obtain the three-dimensional imaging by the Fourier-conversion. Moreover, after the selective excitation of spins within an X-Y surface, a 180.degree. radio frequency pulse is applied. As varying the time difference .tau..sub..epsilon. between the interval from the excitation until the application of the 180.degree. radio frequency pulse and the interval from the application thereof until a peak of a first echo of an echo train, three-dimensional imaging is carried out with a chemical shift axis as one axis by repeating the sequence and accomplishing Fourier-conversion with .

Abstract: An NMR imaging method for measuring a magnetization distribution of an article under test, particularly the magnetization distribution including a longitudinal relaxation effect, by a Fourier imaging method with identification of polarity of the magnetization distribution.A homogeneous phantom is measured by the Fourier imaging method and image-reconstructed so that a reference image data which reflects a phase rotation inherent to an NMR imaging apparatus is obtained. Then, a magnetization distribution of an article under test is obtained in a similar measurement and image reconstruction sequence, and products of the reference image data and the image data of the article under test are stored as the signs to represent the polarity of magnetization of the article under test.

Abstract: An NMR imaging method which provides a three-dimensional image representative of the two-dimensional distribution of nuclear spin species resolved by chemical shift or the local spectra resolved by two-dimensional location. After the excitation of nuclear spins and the phase-encoding by application of a field gradient G.sub.y, a periodically inverting field gradient G.sub.x is generated to yield a continuous echo train. The echo train is sampled and separated into data of odd-numbered echoes and data of even-numbered echoes which data are in turn reconstructed into two-dimensional data arrays, respectively. The data thus reconstructed are three-dimensional Fourier-transformed.

Abstract: An NMR imaging apparatus and method for detecting a nuclear spin resonance signal from an object, which is placed in a magnetic field, to produce images of the object. At an instant when the spins come into phase after the signal detection by a first spin excitation, RF magnetic field pulses are applied for rotating the direction of the spin to that opposite to the initial state. After that, the spin excitation and the signal direction of second time are conducted to measure the data which are different in the effect of the relaxation time from the first measurements. By repeating these sequences, it is possible to produce a plurality of images such as an intensity image or a relaxation time enhanced image.

Abstract: A method of measuring a static magnetic field distribution in a nuclear magnetic resonance (NMR) inspection system which comprises magnetic field generator for producing a static magnetic field, inclination or gradient magnetic fields and a high-frequency magnetic field, a signal detector for sensing nuclear magnetic resonance signals from an inspection sample, a computer for processing output signals from the signal detector and an output device for providing a computational result of the computer, wherein a time interval t.sub.1 from the center of a 90.degree.-pulse high-frequency magnetic field to the center of a 180.degree.-pulse high-frequency magnetic field is made different by a time difference t.sub.0 from a time interval t.sub.2 from the center of the 180.degree.-pulse high-frequency magnetic field to a peak of a spin echo, so that static magnetic field distribution is calculated based on the computer output which corresponds to the difference of the two time intervals.

Abstract: An NMR imaging apparatus and method for direct Fourier imaging. This apparatus includes a static magnetic field generator, gradient magnetic field generators, high-frequency magnetic field generator, signal detecting detector for detecting a nuclear magnetic resonance signal from a body to be inspected, a computer for performing an arithmetic operation for the detected signal to obtain the nuclear magnetic resonance intensity distribution in the to-be-inspected body from measured values of the nuclear magnetic resonance intensity distribution at various points on a rectangular coordinate system in the Fourier space, and memories used for correction.

Abstract: An NMR imaging method and apparatus of the type in which a 180-degree RF pulse is applied to generate a spin echo after the selective excitation of a spin by a 90-degree RF pulse. A dummy gradient field, which has the same direction and intensity as those of a gradient field to be applied when the spin echo is observed, is applied between said 90-degree RF pulse and said 180-degree RF pulse so that the instant of starting the application of the gradient field for signal observation is advanced to the extent corresponding to said dummy gradient field.

Abstract: An NMR imaging apparatus for reconstructing a cross section of a body to be inspected, by the projection-reconstruction method. That is, an apparatus for forming the above cross section in such a manner that the nuclear magnetic resonance is caused by the to-be-inspected body in the resulting magnetic field of a static magnetic field and a rotatable gradient field, a projection of the to-be-inspected body is detected at each rotational positions of the gradient field, and the cross section is reconstructed using the above projection. The apparatus comprises memories for previously storing therein data indicating the distorsion of magnetic field such as the non-uniformity of the static magnetic field and the non-linearity of the gradient field, in order to perform the coordinate calculation in the back projection, using the data stored in the memories.

Abstract: A multielement scintillation radiation detector comprises a scintillator and a photosensitive detector, wherein to optically isolate between the adjacent radiation detectors, a thin light reflecting sheet on which a sponge material is attached is used to closely adhere to radiation shielding plates for partitioning each radiation detector.

Abstract: A radiation detecting apparatus includes a pair of substrates disposed face to face in such a manner that a plurality of grooves provided in one of the facing surfaces at a predetermined interval face a plurality of grooves provided in the other of the facing surfaces at the predetermined interval. Radiation shielding plates are inserted at both ends thereof into a facing pair of grooves to be held by both of the substrates, scintillators are mounted on a corresponding one of the radiation shielding plates, and photodetectors are fixed to either one of the facing surfaces of the substrates between adjacent grooves so that a plurality of facing pairs of photodetectors are juxtaposed.

Abstract: In an imaging apparatus using nuclear magnetic resonance which includes apparatus for generating a static magnetic field, a linear gradient magnetic field and a radio frequency magnetic field, respectively, signal detection device for detecting the nuclear magnetic resonant signal from an object to be inspected, a computer for calculating from the detection signal an image and output device for displaying the result of calculation by the computer, the improvement wherein the size of the object to be inspected is detected by use of ultrasonic wave or light beams and a signal indicative of the detected size of the object is applied to the linear gradient magnetic field generation apparatus so as to control the intensity of the linear gradient magnetic field.

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: An imaging apparatus using nuclear magnetic resonance is disclosed in which both an image corresponding to the projection of a nuclear spin distribution in a to-be-inspected object on a two-dimensional plane and a display mark indicating a desired measuring position are displayed on a display face of a display device such as a CRT display, the display mark is freely moved on the display face to be set at a desired position on the display face, and magnetic field generating means for generating a static magnetic field, linear gradient field, or radio frequency magnetic field is controlled on the basis of the desired position of the display mark to obtain an image of that cross section of the object which is located at a position indicated by the display mark.

Abstract: A scanning-image forming apparatus using a photo-response signal according to this invention is constructed so that the photo-response signal obtained by scanning the surface of a semiconductor specimen with a photon beam is subjected to a 2nd differentiation, and that an image is displayed by employing the 2nd derivative of the photo-response signal as a modulation signal.

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: An electromagnet having a current detecting device for detecting the current flowing through an electromagnet exciting coil, the output of which is utilized to control the power supplied to the coil to stabilize the current flowing through the coil; the electromagnet further including a separate power supply to supply current to the current detecting device which supplies current to the current detecting device when the electromagnet is not on working.

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: 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: In radiation detection apparatus apparatus having a plurality of radiation detector each comprising a scintillator which emits light in response to a radiation, and a photodetector which detects an emission intensity of the scintillator; radiation detection apparatus characterized in that the scintillator is made of a layer of phosphor particles, so that the performances of the respective detectors are substantially identical.