Abstract: A magnetic resonance imaging system has a electromagnet coil assembly for exciting nuclei of an animal placed within the assembly and a mechanism to receive magnetic resonance signals from the nuclei and reconstruct an image of the animal from those signals. A plethysmograph is provided to sense the peripheral arterial pulse of the animal and gate the MRI system. A sensor for the plethysmograph includes a fiber optic cable having a pair of optical fibers which extend into the magnet assembly. A probe is connected to one end of the cable and is adapted to be attached to a digit of the animal so that ends of the optical fibers are adjacent the animal's skin. The other end of the cable couples to a circuit which sends light through one of the optical fibers to the probe, and which receives light returned from the probe through the other optical fiber. The circuit produces an electrical signal corresponding to the intensity of light received from the other optical fiber.

Abstract: A system for writing cursors on a raster scanned television screen that uses the microprocessor in a display controller to produce blocks of data defining the parameters of vectors that compose the cursor. The blocks are put in a first-in first-out memory during a vertical blanking inerval or during active picture time. Each block specifies where writing of a cursor segment is to start and stop on a horizontal scan line and it also specifies a repeat count that indicates the number of lines on which the segment is to be written. Each block contains a delta value to indicate how much, if any each segment is to be displaced left or right from line to line so vertical and angulated vertical vectors can be produced. The blocks are read out of the memory consecutively by a circuit that converts the segment start and stop data to pixel counts. Pixel counters determine the writing start and stop points.

Abstract: Data derived from multiple x-ray views of a body layer is processed in accordance with an image reconstruction algorithm by a central processing unit (CPU) to result in a matrix of digital data corresponding with picture elements (pixels) which are for being displayed on a tv or video monitor. A device for delineating or identifying a region in the displayed picture with a box, irregular trace, or cursor with a bright dotted line uses a trackball to generate data signals corresponding in position with pixels in the matrix. The trackball generated data is processed for producing video picture modulating signals corresponding with the pixels in the matrix to which they positionally relate. The modulating signals are overlayed on the composite video signals from the display controller with a video mixer.

Abstract: In a gamma camera system a computer calculates the x and y coordinates of scintillations and a pulse height analyzer determines if they are within the proper amplitude limits for being displayed on a cathode ray tube at corresponding coordinates. Means are provided for correcting nonuniformity or lack of correspondence between the positions of the scintillations and their calculated coordinates. In an accumulation mode, a first memory matrix stores pulse counts for incremental areas of the radiation field when a uniform source is presented to the detectors. When a predetermined maximum number of counts is reached in at least one memory location accumulation is interrupted at which time other locations have fewer counts in them. In the run mode counts are stored in corresponding locations in a second memory matrix and these counts are compared continuously with those in locations in the first memory.

Abstract: A cathode ray tube for displaying images corresponding with isotope radiation emissions uses electrostatic focusing means, magnetic deflection means and a fast amplifier for driving the deflection coils. Power supply voltages for the amplifier are programmable in correspondance with selected image size. Means for correcting focus within image areas, means for compensating the effects of tube aging and means for protecting against deflection failure are provided. Means for displaying visual indications of the status of the image making sequence are provided.