Abstract: An X-ray apparatus has a motor for moving its components in different directions. A collision sensor is formed by a bladder attached to a component of the apparatus and deformation of the bladder produces a change in the pressure of air within the bladder. The bladder has an air vent to the atmosphere which can be sealed by operation of a valve. A pressure sensor produces two control signals when the pressure within the bladder exceeds first and second threshold levels respectively. The second threshold level is greater in magnitude than said first threshold level. The first control signal closes the valve and causes a motor control circuit to discontinue any application of electricity to the motor. The second control signal opens a switch through which electricity normally flows to the motor. A mechanism also is provided to simulate a collision by compressing the bladder to test the operation of the detection system.

Abstract: A collision sensor specially adapted for a power driven x-ray imaging apparatus includes a face collision sensor and an edge collision sensor. The face collision sensor has two annular plates which are biased apart longitudinally by three flat springs which are equiangularly spaced apart around the perimeter of the plates. Three equiangularly spaced cables hold the plates in parallel planes with the springs prestressed and collapse to allow the plates to be compressed together. Two sets of three switches each reside at equal angular intervals between the plates, with at least one of the switches of the first set being actuated when any point across the face of the sensor has been moved a predetermined longitudinal distance. At least one of the switches of the second set is actuated when the point on the face of the sensor has been moved a further predetermined longitudinal distance. An edge collision sensor includes a closed air bladder which surrounds the face collision sensor and in which a vacuum is drawn.

Abstract: A method is provided for reducing acoustical noise generated when gradient coils which are part of a nuclear magnetic resonance (MR) scanner are energized by current pulses in the course of an MR study. The acoustical noise is due to vibrations of a fiber-glass coil form on which the coils are wound. The vibrations are excited by high frequency components in the squared-edged conventional current pulses. Significant noise reduction is achieved by shaping the leading and trailing current pulse edges to eliminate the objectionable high frequency components. Advantageously, the pulse edges can be shaped using sinusoidal and Bessel function waveforms. Another useful waveform for pulse shaping is a ramp function with rounded transition points.

Abstract: Curved X-ray filter elements are arranged circularly around a drum. Alternate circumferentially adjacent elements have different filtration properties. Diametrically opposite elements have the same properties. An X-ray source provides a sequence of alternate low and high energy X-ray beam pulses. A multicell X-ray detector produces X-ray attenuation data for each pulse and the data is switched to alternate memories. A drum drive motor is energized at power line frequency. A pinion on the motor shaft turns a gear. A lug that is mounted for angular adjustment on the gear drives the drum. A multiple blade shutter is also mounted on the gear for angular adjustment and rotation with the gear. The shutter alternately interrupts and restores a light beam to a photosensitive device which produces corresponding signal state changes or trigger signals. The signals are used to synchronize the low and high energy X-ray pulses, the filter element angular locations and memory switching with power line frequency.

Abstract: A mobile medical diagnostic device having a mobility chassis with two supporting wheels and a central steerable drive wheel. The device has an electrical power steering system controlled by two synchronized handles operable by wrist action of an operator walking behind the device. The handles include a rotatable grip for controlling the velocity of the device. Advancing the grip actuates the throttle to the drive wheel and retarding the grip actuates a proportional electromechanical braking system. The device includes a proximity detector system which uses ultrasonic transducers to determine when an obstacle is within close proximity to the device, and to responsively and automatically actuate the brake system. The device has a stabilization system which automatically extends an outboard support on each side of the central wheel when the device is positioned for diagnostic analysis and automatically retracts the supports to facilitate mobility of the device.

Abstract: In a spot film device, the inner and main carriages for a film cassette are positioned with reversible servo motors. An x-ray grid is mounted on the bottom of the main carriage and a cross grid is mounted on tracks beneath the carriage such that the cross grid may be used or not used for fluoroscopy and both grids may be used for radiography. Field defining masks are also mounted for translating selectively with the carriage. Individual reversible servo motor drives are used to advance and retract the masks and cross grid. Means are provided for absorbing shock or negating drive system momentum when the masks or grid are stopped abruptly. Reduced power is applied to the mask and grid drive motors when the masks and grid reach their stops for holding them against their stops. A motor driven palpator cone, having unique driving and locking means is provided. Means are provided for loading and unloading cassettes from either the front or rear of the spot film device.