Abstract: Installation allowing the adjustment of compensating filters without exposure to permanent irradiation. According to one possible embodiment, a radiological image is taken (source, brightness or luminance amplifier) and memorized in an image memory prior to being projected by the video projector onto the patient by through-crossing the filter, this filter having brightness absorption and X-ray absorption properties which are similar.

Abstract: The present invention relates to an X-ray tube with a rotary anode and to a process for fixing a rotary anode to a support shaft contained in such a tube. The rotary anode is fixed to the support shaft with the aid of a deformed element, positioned between the rotary anode and the support shaft, concentrically to the latter, and acting in the manner of a stuffing box.

Abstract: According to the invention, the system comprises a resonance type inverter, a diode rectifier bridge and single regulation loop controlling controlled switching means, forming a chopper, interconnected between the rectifier bridge and the inverter. The system is applied to X-ray equipment.

Abstract: The invention concerns a simplified control tilting examination frame. According to the invention, the frame comprises a table, a base and a pivoting support while the control system of the displacement of the table with respect to the support is servo-controlled by a representative signal of the tilting of the said pivoting support, in order to prevent under any circumstances one end of the table from touching the ground. The invention applies to medical radiology.

Abstract: The invention is related to the compression of digitized data to load a buffer memory with a view to the transfer of data towards a mass storage.The invention consists especially in transmitting the difference D.sub.n between two consecutive pixels X.sub.n-1 and X.sub.n instead of these latter, this difference being the most often codable on a small number of bits and in suppressing the sign bit whenever possible, i.e. each time that the indetermination on the sign is raised by the comparison between D.sub.n and X.sub.n-1. The process and device according to the invention are adapted to be applied, in particular, to the storage of images.

Abstract: An echography apparatus comprising a probe reconstituting mobile rings by element switching, said probe comprising a plurality of transducer elements spread over a convex coupling surface, and switching means being provided for grouping together certain transducer elements into rings.

Abstract: A method and apparatus for positioning a patient with respect to an X-ray installation. An X-ray image is produced at the beginning of the operation and stored in an image memory. The memory is read in order to visualize the X-ray image on a television receiver. The table is displaced to a desired position, and the image in the receiver is decentered so as to reproduce the image that would be observed if an X-ray were taken at the desired position.

Abstract: The invention relates to a method for characterizing the structure of a medium in which the ultrasonic absorption coefficient of the medium is measured. In order to perform a spectral analysis of this absorption, the spectrum of the signal reflected after it has been transmitted is evaluated by means of an autocorrelation method. Application: medical practice.

Abstract: The invention relates to an electron gun for a linear accelerator, able to supply a modulated electronic current for injection into an accelerating structure. Such an electron gun comprises a cavity resonator in which a cathode and a grid define a grid--cathode space, on which is closed said cavity resonator. An electromagnetic wave injected into said cavity resonator defines, with the grid and the cathode, an alternating potential difference by which the electronic current is modulated. The invention more particularly applies to industrial irradiation machines.

Abstract: The invention relates to a rotating anode X-ray tube provided with a charge flow device, in which the anode current of the tube is established between an emitter coupled in rotation to the rotating anode, as well as a fixed collector. The latter is electrically connected to high voltage and the emitter is electrically connected to the rotating anode, having at least one part with a tapered end constituting an electron emissive zone. These electrons are trapped by the collector, so as to establish the anode current of the tube without any material contact between the emitter and the collector. The invention is applicable to radiology in general and more specifically to medical diagnosis.

Abstract: The invention provides a self-focusing cavity for accelerating charged particles, intended to form the first or only cavity of a linear accelerating structure; this structure accelerating a charged particle beam along an axis merging with a longitudinal axis of this structure. The cavity of the invention comprises an input wall sloping with respect to said longitudinal axis so as to form a surface of revolution providing a charged particle focusing effect.

Abstract: The invention relates to a method of measuring the flow parameters of a fluid, and to a device utilizing this method, in which the autocorrelation function of the signal transmitted back by a particle of the fluid in motion is calculated. The mean speed and the variance of the flow are calculated by calculating the derivations of orders 1 and 2 of this autocorrelation function.

Abstract: A hyperthermia apparatus primarily applicable to the treatment of tumors comprises at least three high-frequency generators connected to three electrodes. The electrodes are intended to be coupled to a patient's body which constitutes the load, thus producing a higher temperature rise in the vicinity of a fictitious electrode in the body. The generators have adjustable phases and amplitudes, the output of each generator being connected to each of the three electrodes.

Abstract: A process of utilizing ultrasound for acquiring data representative of the internal portions of a structure and the display of the data thus obtained. This process includes the emitting of sequences of ultrasound to the structure under consideration and receiving therefrom corresponding echoes. For each sequence two groups of transducer elements are selected for generating ultrasound beams of possible N different focal characteristics sequentially. The ultrasound beams alternate from one group to the other except when a given beam corresponds to the most distant focal zone. In that case, the succeeding emission is carried out without alternating, i.e., the emission is generated from the same group.

Abstract: The invention provides a retractable cassette holder for a combined X ray and radiographic examination apparatus. This cassette holder forms a mobile assembly comprising means for forming a recess with variable dimensions in the middle thereof and means for causing the barrel of a luminance amplifier to slide within this recess.

Abstract: An ultrasonic probe for accurately determining angular location includes a rotating mobile assembly with at least one angular location track placed thereon. The angular location track is inscribed with location data arranged in a succession of pulses. As the mobile assembly rotates, the track traces a path in space. A fixed reading unit is provided at a point along the path to read the data inscribed on the track. The read data contains information corresponding to the angular position of the mobile assembly at any given point in time.

Abstract: The present invention relates to a linear voltage-pulse base-clipping circuit with adjustable-threshold condition.It comprises, for unipolar signals, two lines in parallel. The first line transmits the signal suitably delayed by means of an adjustable delay line to an attenuator which is controlled by the second control line which provides, depending on the threshold condition, the adjustment of the transfer of the attenuator.

Abstract: In an industial installation which is inaccessible during operation, acoustic-emission testing of each measurement line is performed by means of at least one transducer and a preamplifier which is connected to an acoustic signal processing unit by means of a signal transmission line and a supply line. A potentiometer circuit placed on the supply line produces a variation in the supply voltage and remotely operates a relay for switching the measurement line to testing means comprising a local pulse generator connected between the transducer and the preamplifier.

Abstract: An apparatus for measuring acoustic emission is activated only at critical periods which are determined by detection of the background noise from a reference level. An acoustic emission transducer continuously transmits a signal to a detection circuit which delivers the top modulation envelope of the background noise to a comparator at a reference level delivered by a control unit.When a mean level of the background noise does not exceed a threshold reference level the AE is sampled at a low rate, f. When the background noise exceeds the threshold reference level the data sampling unit is activated to sample AE at a much higher rate F. Therefore AE is sampled at a high rate only when the pump or other machine under test is running and at a low rate when the article under test is not operating. The AE testing device also includes a frequency spectrum correlator which allows background noise to activate the increased sampling rate only if the noise is in a given frequency range.

Abstract: A device for storing a source of photons and for irradiating a body by the radiation from said source, comprisinga body for biological protection provided with a cylindrical cavity of circular section and two so-called first and second passages respectively, these passages opening at one and the other of their ends in said cavity and on the outer wall of the body,a disc for biological protection, whose shape is complementary of that of the cavity of the body and presenting, on the one hand, a housing centered on an axis perpendicular to the axis of the cavity, this housing opening out on the side wall of the disc,a source of Y radiation contained in said housing,a precollimator disposed at right angles to said first passage,means for rotating said disc between a first position for which said source is opposite the precollimator and a second position for which the source is in stored position.