Abstract: As disclosed herein, a new and improved method and apparatus provide for fine tuning the position of a servomotor used to drive a transducer mounted on an ultrasound probe to a desired position. This improvement is accomplished by processing the analog quadrature output signals of an incremental optical encoder, coupled to the servomotor. The improvement uses the positional information derived from the analog quadrature output signals. The analog quadrature output signals, defined as sine and cosine, are converted to digital square waves. The digital square waves are decoded to produce digital position quadrants, wherein each quadrant represents a specific motor position. The corresponding digital square waves are also decoded by a logic array device and coupled to the select input of an analog switch.

Abstract: A pulsed power supply for providing power to a piezoelectric crystal. The power supply provides power to the piezoelectric crystal causing contraction of the crystal. Upon reaching a predetermined degree of contraction, the electrical voltage form the power supply is removed from the piezoelectric crystal by creating a short-circuit between the power supply and the crystal. Removal of electrical voltage from the crystal causes the immediate expansion of the crystal and a resulting energy wave.

Abstract: An ultrasound probe 20 includes a transducer 32 capable of pivotal and rotational motion where the pivotal motion is through the plane of rotation. The transducer 32 is also capable of revolving around an axis of revolution 132 so that the transducer 32 can move relative to three axes. The probe 20 is designed such that the transducer 32 can be mounted at the tip of said probe 20 and allow for the above freedom of motion.

Abstract: A biopsy attachment 90 for a ultrasound probe 10 includes a frame 92 and a device 100, 102 for mounting the frame 92 to the probe 10 in order to align the frame 92 relative to the probe 10. The biopsy 90 attachment further includes a biopsy needle guide 106 and a device 94, 96 for pivotally moving the biopsy needle guide from an undeployed position, adjacent to an ultrasound transparent window 24, to a deployed position which is above and spaced from the ultrasound transparent window 24, in order to guide a biopsy needle 132 to the desired biopsy location.

Abstract: An automated magnetic field shimming process for magnetic resonance spectroscopic imaging (MRSI) uses doubly phase encoded NMR spin echo responses in conjunction with multiple fourier transformation to derive a spectroscopic plot for each voxel in a three-dimensional array of voxels in an image volume (including portions of a living subject) which is to be subsequently subjected to MRSI using NMR FID or spin echo responses. The thus derived hydrogen peak frequency is taken as a measurement of existing static magnetic field intensity within that voxel and adjusted shim coil currents are calculated so as to reduce or minimize nonuniformity of the static magnetic field. A nonexistent pseudo shim coil having an assumed uniform shim contribution may enhance the resulting field homogeneity. The auto shimming procedure may be applied iteratively as required to achieve the predetermined degree of field uniformity.

Abstract: A mobile X-ray machine utilizes batteries to provide electrical power to produce high-voltage necessary to generate X-rays during a X-ray exposure. A battery charger circuit is used to supplement the battery during the X-ray exposure and charges the batteries during non-exposure periods. By using batteries to power the X-ray generating device, the X-ray machine is capable of being operated from 110 volt AC power sources permitting the machine to be mobile due to its ability of being operated from ordinary house current.

Abstract: A dynamic calibration and self-check circuit for a mobile X-ray machine. A high voltage regulator circuit provides dynamic regulation of peak anode voltage and a tube current regulator circuit provides dynamic regulation of the X-ray filament current which controls the X-ray tube current. In the regulation of the anode voltage, a voltage sensor provides continuous feedback of the actual anode voltage of the tube to the regulation circuit. A processor selects a predetermined value for the pulse width duration of the high voltage regulator. When an exposure cycle commences, the preselective value is compared with the actual sensed value in an error amplifier. The error amplifier generates an error signal which varies the pulse width of the drive signal to control the peak high voltage to the anode. In the control of the tube current, a sensor which measures the actual tube current is compared with a predetermined value selected by the processor in a second error amplifier.

Abstract: A positioning device for a surface coil used in NMR scanning is described. A non-metallic container allows a MRI surface oil to reside therein. An elongated rod extending through an opening on a side of the container is attached to the coil. A clear cover is placed over the container which is then placed under the patient. As the NMR scanning is performed for medical diagnosis, the coil is adjusted to the desired position by movement of the rod.

Abstract: A surgical instrument guide for use in conjunction with an ultrasound probe and the method of use is described. The guide comprises an ultrasound probe socket disposed in a housing so that it can pivot or be locked in place with respect to the housing. An instrument holder adapted to fit in the probe socket and hold a surgical instrument along its longitudinal axis is also provided. The housing has external threads on the bottom thereof to enable the device to be screwed into the skull.

Abstract: A transducer drive assembly is disclosed having particular application for use in medical diagnostic imaging systems. The drive assembly includes a rotor coupled to drive means for rotation about its longitudinal axis. The rotor is formed such that it includes an integrally formed contact plate which extends upwardly from a generally flat rotor face at a given angle. A transducer is carried in a cradle which is mounted for pivotal movement, and includes a lower base portion having a generally cylindrical cross section. The lower base portion of the cradle is disposed such that it is maintained in physical contact with the rotor contact plate at all times. The rotation of the rotor applies force to the lower base of the cradle resulting in the oscillation of the cradle about the pivot points. The transducer is thereby oscillated back and forth about the pivot points in a uniform and continuous movement so long as the rotor continues to rotate.

Abstract: An ultrasonic scanner for medical diagnostics is disclosed. The scanner includes an upper head assembly and a lower drive assembly. The upper head assembly includes a fluid chamber filled with a liquid acoustic couplant. An oscillating transducer is driven in an asymmetric motion by a linkage coupled off-center to a flywheel within the fluid chamber. An inflatable bladder is provided in the upper assembly which is in fluid communication with the fluid chamber. The application of force to the membrane boot of the scanner forces fluid into the bladder. Once the external pressure is removed, the bladder is biased such that it is compressed, thereby forcing fluid to return to the fluid chamber and maintaining a generally constant pressure within the chamber. Supporting electronics are provided including means for compensating for the asymmetric motion of the transducer.

Abstract: Imaging information characterizable as a pixel grid or matrix of 256 image columns and 512 image rows is supplied by a scanning transducer means delivering a series of ray lines of information where each ray corresponds to an image column. The incoming pixels of the rays are converted into digitized data words, and stored for scan conversion by being routed, in simultaneous blocks of eight words, to a respective one of eight different page memories, in accordance with an image memory organization scheme assigning a different page routing number to each pixel of a block for the entire image matrix, to enable parallel memory access for both input and output operations. The first page for the first pixel of each incoming ray is determined by logic which subtracts the ray or column number from eight, modulo 8. Subsequent pages are generated by incrementing repetitively within the range 0, 1, 2 . . . for each subsequent incoming pixel, after being set to said first page number.

Abstract: A power supply particularly suited for driving coils in a magnetic nuclear resonance device, or scanner, is described. Bipolar switches driven by field-effect devices are used to couple the coil to a high potential when a rapid current change is required, control devices also comprises bipolar transistors driven by field-effect transistors are used to control the current through the coil in steady state conditions.

Abstract: A multi-mode scanner head employing split (semicircular transducers) is described. In some modes such as simultaneous B-scan and M-scan each transducer moves independent of the other. For continuous Doppler mode the transducers move together. The relatively small, hand-held scanner head is particularly useful for cardiac examinations.

Abstract: Improvements are disclosed in an ultrasonic display and recording system of the type utilized in diagnostic medicine with particular applicability in cardiovascular diagnosis. The system includes a multi-element transducer for generating and receiving ultrasonic energy which is propagated into and reflected back from the cardiovascular region of the patient being examined, and also includes means for generating a two-dimensional real time display and/or image of the zone of examination. TM recording means are associated with the system and may be actuated to effect a TM recording corresponding to a preselected region of the real time image being observed. An ECG output signal is also displayed in real time with the two-dimensional image, and photographs of the displays may be produced at selected points in the ECG cycle in accordance with a setting made by the system operator.

Abstract: A data acquisition head for an ultrasonic imaging system which employs a plurality of transducers is disclosed. The transducers are rotated in a liquid filled chamber at a constant rate, each about an axis perpendicular to its transmission axis. The transducers are sequentially activated as their transmission axes cross a semi-rigid membrane which is in contact with the body. The acoustic impedance of the liquid and membrane, and the thickness of the membrane, are matched to enhance transmission. In one embodiment, the membrane is one-half or a full wavelength thick and comprises a low density polyethylene and the liquid has an acoustic impedance approximately equal to that of the polyethylene.

Abstract: An ultrasound imaging apparatus is described. The hand-held device includes a first oscillating transducer for providing a B-scan display and an offset second transducer which is manually positioned for providing Doppler data. The transducer pulses are interlaced and Doppler transmissions are inhibited to permit B-scan transmissions. However, circuits provide a continuous signal representing a Doppler signal when the Doppler transmissions are inhibited.

Abstract: In a receiver for pulsed ultrasonic beams, it is sometimes desirable to translate the received signal to a lower carrier frequency by a heterodyne process. It is also often desirable to vary the receiving channels' gain during the period when signals are being received from a single transmitted pulse, to compensate for the attenuation of later-arriving signals from a greater distance. To get both the heterodyne and the time-gain control functions in a prior-art receiver of N channels requires 2 mixers in each channel, or 2N mixers. According to the invention, the heterodyne and the time-gain control signals are combined in one master mixer and fed to all the channel mixers. The only N+1 mixers are required.

Abstract: An improvement in an ultrasonic imaging system is disclosed, enabling determination of volume and/or shape of three-dimensional portions of bodily tissue or the like.