Abstract: A tomographic scanner includes an imaging device for obtaining images of the anatomy of a patient. A localizer device such as an articulated arm includes a base portion mounted in a fixed relationship to the imaging device and a free end adapted for selective movement into varied positions near a patient body disposed on the imaging device. A guide device such as grid lattice is attached to the free end of the arm. A position transducer associated with the localizer device generates information as to the position of the localizer and hence the position of the guide device in scanner coordinates. The guide device contains a plurality of needle guides. The position of the guide device is displayed in relation to images of the anatomy of the patient. This information is used by the operator to guide the insertion of brachytherapy seeds in a desired pattern and location in relation to the anatomy of the patient.

Abstract: A magnetic resonance imaging system includes a patient couch (10) which selectively positions a patient relative to an examination region (14). An imaging coil (B) is disposed adjacent to a region of interest for receiving magnetic resonance signals emanating from the patient. A processor (48) both controls the imaging event and processes received signals from the imaging coil. A plug and socket assembly (24, 26) having a proximal component and a distal component relative to the imaging coil provides selective electrical connectivity between the imaging coil (B) and the processor (48). A non-volatile memory device (86), such as a 1-WIRE™ EEPROM, is affixed to the proximal component of the plug and socket assembly (24, 26) for storing a variety attributes associated with the imaging coil. The memory device is most conveniently mounted to a coaxial connector (110).

Abstract: Data collected from a cone beam scanner is reconstructed by defining a plurality of oblique surfaces (44) which are reconstructed into a reconstruction cylinder (C). An interpolator (52) identifies non-redundant rays that intersect a center point of each oblique surface (70) along with rays tangent to surface rings on each oblique surface (72, 74). Data from the non-redundant rays is weighted by a first data processor (54). A second data processor (56) convolves the weighted data and passes it to a backprojector (58) which backprojects the data into an image memory (60). The oblique surface reconstruction technique facilitates the use of conventional two-dimensional convolution and backprojection techniques that enjoy relative computational simplicity and efficiency as well as three-dimensional reconstruction techniques that use a minimum number of projections.

Abstract: A magnetic resonance apparatus includes a main magnet (12) which generates a main magnetic field through and surrounding an examination region (14). The main magnetic field contains inhomogeneities which affect image quality. A gradient coil assembly (22) generates gradient magnetic fields across the examination region, which contain higher order harmonics causing inhomogeneities in the gradient magnetic field. A multi-axis shim set (23) is selectively excited in order to cancel both the main magnetic and gradient magnetic field inhomogeneities. More particularly, DC currents are applied by a shim coil power supply (25) to cancel the main magnetic field inhomogeneities. AC current pulses are superimposed on the DC currents by the shim coil power supply (25) in order to correct the gradient magnetic field inhomogeneities.

Abstract: A method for determining a time for acquiring contrast-enhanced images from a CT scanner of a subject into whom a contrast medium has been injected, the method including: identifying a region of interest in an initial CT image of the body of a subject; defining an attenuation data segment corresponding to the region of interest by reprojecting the region of interest in the initial image; receiving attenuation data within the segment from a subsequent scan of the patient; and independently processing the attenuation data received within the segment to estimate an optimal time for performing a diagnostic scan of the body, without reconstructing all or a portion of the CT image.

Abstract: A method and apparatus for image processing on a radiation image which may be a conventional radiographic image on X-ray film or a radiation image which is stored in a stimulable phosphor and read out therefrom. The radiation image is scanned by a light beam or stimulating rays and an image signal is obtained by use of a photodetector. The image signal is subjected to a frequency processing by use of an unsharp masking process. The unsharp mask signal (Sus) is used for conducting an operation ofSorg+.beta.(Sorg-Sus)to obtain an image-processed signal S, wherein Sorg is a digital signal for each picture element of the scanned image and .beta. is a frequency emphasizing coefficient. The median of a group of digital signals in an unsharp mask of a predetermined size is employed.

Abstract: A method and apparatus for computed axial tomography (CAT) image reconstruction applicable to X-ray scanning of the human body. Successive series of calculations determine the values of a characteristic in defined segmented areas of an examination plane. A reduction in the time and equipment requirements for reconstruction calculations may thereby be effected.Images representative of the difference between the value of the characteristic at a reconstruction point and the average value of the characteristic in adjacent regions (.DELTA..mu.) may be calculated and displayed from measurements taken within a localized contiguous region of the examination plane. Radiation dose to patients and computation time in X-ray computerized axial tomography scanning systems is thus reduced. Differential displays of the type described may be adjusted to image boundaries, in which case they do not suffer from gray scale resolution problems which are typical of prior art displays.

Abstract: Measurement of magnetic field distributions is performed using a method based on the nuclear magnetic resonance (NMR) technique of Pourier imaging. By selecting objects which limit the spatial distribution of the NMR observable nuclei, images can be obtained which allow easy interpretation of the magnetic field distribution and facilitate rapid shimming of magnets. A method for providing a convenient display of field data is provided, as well as chemical shift imaging with correction for static field inhomogeneity. Results from these field plots are used as corrections for static field inhomogeniety when obtaining a chemical shift image. A method for localized spectral analysis from the chemical shift image is also provided.

Abstract: A method and apparatus for regulating and stabilizing the radiation intensity level of an X-ray source. The apparatus includes high voltage circuitry for supplying anode and cathode voltages to an X-ray tube and filament voltage circuitry for supplying voltage to the filament of the tube. Both the high voltage and filament voltage circuitry are regulated by multiple feedback voltage level control circuits. The method of the present invention involves the forming of the high voltage and filament voltage circuitry and the supplying of appropriate feedback signals to such circuitry to maintain the high voltages and filament voltage at desired levels.

Abstract: A method and apparatus for computed axial tomography (CAT) image reconstruction applicable to X-ray scanning of the human body. Successive series of calculations determine the values of a characteristic in defined segmented areas of an examination plane. A reduction in the time and equipment requirements for reconstruction calculations may thereby be effected.Images representative of the difference between the value of the characteristic at a reconstruction point and the average value of the characteristic in adjacent regions (.DELTA..mu.) may be calculated and displayed from measurements taken within a localized contiguous region of the examination plane. Radiation dose to patients and computation time in X-ray computerized axial tomography scanning systems is thus reduced. Differential displays of the type described may be adjusted to image boundaries, in which case they do not suffer from gray scale resolution problems which are typical of prior art displays.

Abstract: A method and apparatus for detecting the presence of caries in human teeth using visible luminescence. A region to be examined is excited with a beam of monochromatic light. The intensity of the visible light emitted from the region is measured at two predetermined wavelengths, one where the intensity dependence of the spectra is about the same for caries and noncaries and the other where the relative intensity increases significantly in the presence of caries. A signal corresponding to the difference in the two intensities is obtained and then displayed. By first determining the magnitude of the difference signal at a nondecayed region, any increases in the magnitude as other regions are probed indicate the presence of caries. The invention is based on the discovery that the visible luminescence spectra for decayed and nondecayed regions of a human tooth are substantially different and that the differences are such that visible luminescence from teeth can be used to detect the presence of caries.