Abstract: An image detector for X-ray technology enables different image resolutions in a simple way. In an a-Si:H detector matrix, several pixels can be fixed via a row lead and a column lead, and these pixels can be interrogated together or, by the use of voltage impulses of different levels or polarity, can be interrogated separately.

Abstract: An x-ray image-generating system having an a-Si:H detector matrix is constructed so that different enlargements are possible with a small number of terminal conductors. Two groups of pixels of the detector matrix can be read out together by means of voltage pulses of different levels, respectively applied in alternation to the two pixel groups on a line conductor common to both pixel groups.

Abstract: An x-ray diagnostic installation has a high-voltage generator, an x-ray tube supplied by the high-voltage generator, and a solid-state image converter on which x-rays, attenuated by an examination subject disposed between the x-ray tube and the solid-state image converter, are incident. A control unit is connected to the high-voltage generator and to the solid-state image converter, and controls the high-voltage generator to cause the x-ray tube to emit a first x-ray pulse of a short duration which produces an x-ray exposure in the solid-state image converter. The control unit conducts a read out of the solid-state image converter to obtain a measured value representative of the x-ray dose rate, the control unit using this measured value to calculate the x-ray transparency of the examination subject and, from the x-ray transparency, to calculate an optimum x-ray dose.

Abstract: An x-ray diagnostics installation has a high-voltage generator for an x-ray tube for generating an x-ray beam, having a detector arranged in the x-ray beam for acquiring the x-ray dose, a control unit connected to the detector for the control of the high-voltage generator, and a solid-state image converter which also serves as the detector. The solid-state image converter has a semiconductor layer with light-sensitive pixel elements arranged in a matrix and an electrically non-conductive layer applied thereon, an electrode layer applied on the electrically non-conductive layer forming a capacitor with the pixel elements to which charge is supplied due to x-ray exposure and that is connected to the control unit for the acquisition of this charge corresponding to the x-ray dose.

Abstract: An x-ray image sensor has a matrix of radiation-sensitive detector elements, the detector elements being connected in two groups to a common read-out line on which bipolar signals are generated. Read-out signals of one polarity cause read-out of one of the groups of detector elements and read-out signals of the other polarity cause read-out of the other group. An image detector having high resolution but low technical outlay is thereby achieved.

Abstract: A solid state image converter has light-sensitive cells arranged in a matrix, each cell formed by two oppositely-connected diodes, at least one diode in each cell being a photodiode, and has driver circuits for driving the diodes, that are connected between the respective row and column lines of the driver circuits. The driver circuits electrically reset the diodes individually or row-by-row by clocking. By briefly forward biasing, the individual photodiodes so that they are briefly brought into the conductive state, and are subsequently reverse biased. The solid state image converter can be continuously exposed with x-rays and is employable in an x-ray diagnostics installation.

Abstract: An electromagnetic pressure pulse source for generating focused pressure pulses as an electrically conductive membrane and a coil system which drives the membrane by rapidly displacing the membrane from the coil system. The coil system is formed by an annular array having a number of annular zones which can be individually activated to cause the generation of pressure pulses in variable chronological relation to each other, which permits the location of the focus of the resulting shockwave to be adjusted with a range, and/or the diameter of the focus to be changed.

Abstract: An apparatus for generating acoustic rarefaction pulses, i.e., a negative pressure pulse, has a pressure pulse source and reflector having a negative reflection factor, and an acoustic propagation medium filling the space between the pressure pulse source and the reflector. The reflector has a boundary surface facing toward the pressure pulse source, consisting of a medium which is acoustically soft in comparison to the acoustic propagation medium. The boundary surface medium is separated from the acoustic propagation medium by a wall which is impenetrable by the acoustic propagation medium.

Abstract: For suppressing reflections of an acoustic reception signal at a transmitting/receiving ultrasound transducer, the ultrasound transducer is connected to a compensation circuit which supplies the ultrasound transducer with a compensation transmission signal during reception, which has a waveform similar to the acoustic reception signal, but with a polarity opposite that of the acoustic reception signal. A summing stage is connected in a reception channel of the ultrasound transducer, the summing unit having a first input supplied with a compensated reception signal, formed by a combination of the acoustic reception signal and the compensation transmission signal. A second input of the summing unit is connected to the compensation circuit, which supplies a signal at the second input which removes the contribution made by the compensation transmission signal from the compensated reception signal, so that the output of the summing unit generates a reception signal devoided of the compensation transmission signal.

Abstract: An ultrasound apparatus has a first group of transmission and reception channels that are respectively allocated to elementary transducer in the active aperture of a connectable transducer array. The central transmission location generated by a transmission channel and the reception location sampled by a reception channel coincide and lie on the allocated elementary transducer. In addition, a second group of transmission and/or reception channels is present, each being respectively simultaneously connectable to a plurality of elementary transducers via transmission and/or reception transfer stages for generating a virtual transmission and/or reception location that lies between the elementary transducers.

Abstract: A method for generating an ultrasound image of a plane of a section of an examination subject having a non-uniform speed of sound distribution near the surface of the subject includes the steps of scanning the section plane line-by-line with a transducer array in an adaption phase and calculating values from the received, focussed echo signals which deviate from anticipated values which would arise given a uniform speed of sound distribution, the calculation being undertaken by a cross-correlation function of neighboring elementary transducers. Correction values are formed from the deviating values depending on the angle of incidence of the echo signals on the elementary transducers. In an imaging phase following the adaption phase, the delay values for focussing are modified dependent on the incident angle of the echo signals and dependent on the correction values for this incident angle.

Abstract: In a method for calculating the flow velocity of, for example a blood stream, ultrasound pulses are repeatedly transmitted into an examination region with a spacing of a pulse repetition time (Tr). An autocorrelation function (Kii) and a cross correlation function (Kiq) in an environment (Tr.+-.1.5 T) around the pulse repetition time (Tr) are formed from the quadrature components (i, q) of echo signals of respectively successive transmission pulses. The shift of the maximum (.DELTA.t) of the correlation functions (Kii, Iiq) relative to the pulse repetition time (Tr) as a result of the velocity of the flow is fixed in a region (Bn) wherein the ambiguous, mean Doppler frequency (.omega.) identified in a traditional way lies. The apparatus for the implementation of this method comprises a shift identification circuit for this purpose. This shift identification circuit calculates the shift of the maximum (.DELTA.t) of one or both correlation functions (Kii, Kiq) relative to the pulse repetition time (Tr).

Abstract: An apparatus for generating focused shockwaves, suitable for extracorporeal lithotripsy, has a substantially hollow-cylindrical membrane consisting of electrically conductive material and an electrical coil arrangement disposed inside the membrane which can be supplied with a high voltage pulse to rapidly repel the membrane and thereby generate a shockwave. The apparatus includes a concave reflector in the form of a paraboloid of revolution, which surrounds the membrane and coil, and which has a center axis substantially coincident with the center axis of the membrane. An acoustic propagation medium fills at least the volume between the membrane and the reflector. The shockwave generated by the cylindrical coil and membrane arrangement is reflected and focused by the paraboloid of revolution so that the shockwaves converge at a focus. The apparatus is arranged so that the focus conicides with a region of a patient to be treated with shockwave therapy, such as a calculus.

Abstract: An extracorporeal lithotripsy apparatus for treating a calculus in the body of a patient has a shock wave source which generates shock waves converging in a focus zone, and an ultrasound locating system having a sector applicator with which at least the focus zone can be scanned. The sector applicator includes a number of ultrasound transducers, so that a number of layers, proceeding parallel to each other, can be quasi-simultaneously scanned. The number of layers which can be scanned corresponds to the number of ultrasound transducers. The layers are directly adjacent each other so that displacement of a calculus in the body during treatment in a direction transverse to the acoustic axes of the scanned sectors can be observed.

Abstract: A shock wave source for use in lithotripsy has an electromagnetic shock wave source with the ultrasound head of an ultrasound locating system centrally disposed within the source. During locating of a calculus to be disintegrated, at least one surface normal of the exit face of the ultrasound head is aligned obliquely relative to the surface normal of the coupling surface of the shock wave source. Image disturbances due to multiple echoes are avoided by the oblique positioning of the ultrasound exit face.

Abstract: An apparatus for extracorporeal lithotripsy includes a shock wave source which generates shock waves converging in focus a zone, within which a calculus to be disintegrated is disposed. The shock wave source can be selectively driven to generate high-intensity shock waves for disintegrating the calculus, and for generating low-intensity shock waves for imaging purposes. A pressure sensor is disposed between the focus zone and the shock wave source to register the reflections of the low-intensity shock waves. The pressure sensor has a sensor surface which is substantially coextensive with the cross-sectional area of the shock waves in the region of the pressure sensor, and is connected to a reception circuit which constructs an image of the calculus during the course of treatment based on the signals from the pressure sensor.

Abstract: An extracorporeal lithotripsy apparatus includes a shock waves source which generates shock wave along an acoustic axis in a propagation direction, with the shock waves being caused to converge, either by a curvature of the shock wave source or by the use of a separate focusing element, at a focus region, the lithotripsy apparatus being initially positioned so that a calculus to be disintegrated is coincident with the focus region. During treatment, the calculus may be displaced from its original, identified position by patient movement, such as due to respiration.

Abstract: An ultrasound apparatus has a transducer array which includes a number of individual transducer, each transducer having a channel exclusively associated therewith. In an input stage for the ultrasound apparatus, an analog stage is provided in each channel to which the echo signals for a transducer associated with that channel are supplied. This analog stage concludes with an analog-to-digital converter in each channel. The output of the analog-to-digital converter is connected to a further processing circuit in each channel for the acquisition of Doppler signals of moving target echoes. A combined ultrasound imaging device and Doppler device is thus achieved, which allows the acquisition of Doppler signals with the digital input technology of the ultrasound imaging processing circuit. This permits expansion of digital operating RF input components of imaging devices to include Doppler signal processing.

Abstract: A shock wave source for an extracorporeal lithotripsy system has a number of electro-acoustic transducers arranged in a concave surface, each transducer having an acoustic axis, and the shock wave source having an acoustic axis. The transducers are each pivotally mounted, and a common adjusting element is provided which pivots each of the transducers so that their acoustic axes intersect at a focus, which lies on the acoustic axis of the shock wave source. The common element also permits adjustment of the location of the focus along the shock wave source acoustic axis so as to be more distal or more proximate relative to the shock wave source.

Abstract: A shockwave source of the type wherein a shockwave is generated by rapid electromagnetic repulsion of a membrane by a rapidly energized coil has a central opening extending through the membrane and the coil. An ultrasound head of an ultrasound transmission and reception system is received in the opening. The ultrasound head is disposed in a mount which is rotatable around its longitudinal axis by a rotary drive. In one embodiment of the shockwave source, the shockwave source also has a focusing device disposed in front of the membrane, and in this embodiment the focusing device also has a central opening in which the ultrasound head is received. The ultrasound head has a distal end in contact with a liquid coupling agent for promoting transmission to, and reception from, a patient to which the shockwave source is coupled. The shockwave source is particularly suited for lithotripsy treatment of gallstones.