Abstract: Systems and methods for detecting an image of an object by use of X-ray beams generated by multiple small area sources are disclosed. A plurality of monochromator crystals may be positioned to intercept the plurality of first X-ray beams such that a plurality of second X-ray beams each having predetermined energy levels is produced. Further, an object to be imaged may be positioned in paths of the second x-ray beams for transmission of the second X-ray beams through the object and emitting from the object a plurality of transmission X-ray beams. The X-ray beams may be directed at angles of incidence upon a plurality of analyzer crystals for detecting an image of the object.

Abstract: Systems and methods for detecting an image of an object by use of X-ray beams generated by multiple small area sources are disclosed. A plurality of monochromator crystals may be positioned to intercept the plurality of first X-ray beams such that a plurality of second X-ray beams each having predetermined energy levels is produced. Further, an object to be imaged may be positioned in paths of the second x-ray beams for transmission of the second X-ray beams through the object and emitting from the object a plurality of transmission X-ray beams. The X-ray beams may be directed at angles of incidence upon a plurality of analyzer crystals for detecting an image of the object.

Abstract: Two-dimensional or three-dimensional images of the distribution of a property of an object are formed by passing rays of radiation through the object and detecting how much each ray is attenuated. The Fourier transform is taken of each individual ray but only the zeroth term of the transform along the path of the ray is retained. Each of these transforms is added into a two or thee-dimensional array. If the three-dimensional distribution is being imaged, the transform is a plane of numbers, which is added into the three-dimensional array at right angles to the path of the ray. The numbers in the array are corrected for the non-uniform density of data. After enough such rays in enough different directions are applied, the distribution of the property is obtained by taking the inverse Fourier transform of the data in the array.

Abstract: A biomagnetometer measures a magnetic field produced by a source within the body of a subject, using a magnetic field sensor system. The biomagnetometer includes an ultrasonic transceiver that determines the internal physical structure of the body with ultrasonic waves. An electromagnetic transmitter/receiver establishes the position of the ultrasonic transceiver relative to the magnetic field sensor system. A computer controls and integrates the magnetic field sensor system, the ultrasonic transceiver, and the electromagnetic transmitter/receiver. The biomagnetometer permits a direct association between the measured biomagnetic field and the location of the source within the body of the subject.

Abstract: A biomagnetometer has a magnetic pickup coil positioned remotely from a detector and inductively coupled to the detector. The detector is preferably made from a low-temperature superconductor, while the pickup coil can be made of a high-temperature superconductor. The detector and pickup coil can therefore be placed into separate containers, with an inductive coupler between the containers. In one approach, the detector is maintained at liquid helium temperature, and the pickup coil and electrical connector are cooled by liquid nitrogen. The resulting biomagnetometer permits the container with the pickup coil to be moved and positioned easily, and to be changed readily between various configurations particularly suited for performing various functions.

Abstract: The null point in the gradient field of an NMR imaging system is offset from its nominal position in the static magnetic field by application of a bias field to the gradient field. The bias field produces a substantially uniform offset in the field intensity at every point in the gradient field. Alternatively, null point offset may be achieved by controllably superimposing two gradient fields of separately located null points.

Abstract: The effects of particle motion or flow within a sample may be measured by applying a motion-encoding gradient to the sample, along with spatial encoding gradients. The motion-encoding gradient applies two gradient fields of respective opposite sense to the spins of the sample so as to encode motion as a net phase component resulting from the two fields. Two image data sequences, one with motion encoding and one without, may be compared to measure the effects of motion, or a plurality of image data sequences may be taken, each with a different value motion-encoding gradient. A Fourier transformation performed on the sequence data in the latter case with respect to the variation in the motion-encoding gradient pulses will yield a plurality of images, each representing the amount of material which exhibits a different velocity.

Abstract: Spatially discriminated information is obtained by appropriate processing of data derived from a series of pulsed N.M.R. operations performed with a magnetic field exhibiting a linear gradient whose magnitude is different for each operation. In obtaining a two-dimensional image of spin density distribution, coil sets (5 and 6) are used to generate magnetic field components giving x and y gradients, the former being changed stepwise in magnitude and the latter being fixed. For each value of x gradient, the sample (1) is irradiated with pulsed r.f. energy, resultant N.M.R. signals being detected by phase-sensitive detectors (19 and 20) whose outputs are regularly sampled by A-D converters (25 and 26). Processing of the complete sampled data by a computer (12) involves both Fourier transformation with respect to x gradient magnitude and Fourier transformation with respect to time.

Abstract: Apparatus for generating and detecting magnetic field components oscillating at a radio frequency in a direction transverse to a static magnetic field in a nuclear-magnetic-resonance (NMR) system. The apparatus has a plurality of conductive elements spaced from one another and from the axis along which the static magnetic field is directed. The relative amplitudes of alternating currents in the conductive elements are controlled to generate a spatially uniform field. A preferred embodiment uses a standing wave in a coil assembly to control relative current amplitudes, which takes advantage of the current-phase characteristics of such waves. Detection of RF magnetic fields results from an EMF generated in the coil assembly in response to the time-varying magnetic field; the high Q of the coil assembly enhances detection properties.

Abstract: Nuclear magnetic resonance is excited in a sample subjected a magnetic field having a varying component which defines a localized volume approximating to a line or surface, the field within the localized volume being invariant with time but exhibiting a spatial gradient. The r.f. irradiation is in the form of a pulse train such that the signal received from the sample contains continuous wave components respectively dependent on the density of relevant nuclei in different regions of the localized volume. The amplitudes of these components are determined by coherently detecting the received signal, sampling the detected signal(s) and subjecting the resultant data to Fourier transformation.