Abstract: A method for applying a radiation treatment with an arbitrary isodose profile is disclosed. The treatment apparatus has a radiation source which generates a radiation beam with an axis. The apparatus also includes a collimator having a plurality of independently movable plates disposed in the path of the radiation beam and oriented in a direction perpendicular to said beam axis. Each set has two movable plates. Control signals are generated. Two plates within a set of plates are actuated independently in orthogonal directions during the treatment, in response to the control signals, causing the beam to change in width. The intensity of the beam is changed as a function of the position of the plates to generate an arbitrary beam profile. Exemplary profiles which may be generated included rotationally symmetric parabolic profiles and flat profiles.

Abstract: A system for applying radiation treatment under computer control is disclosed. The system has a radiation source, which generates a variable intensity radiation beam, and a collimator. The collimator has a plurality of movable plates disposed in the path of the radiation beam and is oriented in a direction perpendicular to the beam axis. The apparatus is capable of actuating the plates independently during the radiation treatment, in response to a first control signal. The beam changes in width when the plates are so actuated. The collimator is rotated in response to a second control signal. The intensity of the radiation beam may be varied as a function of the plate position. A total radiation dosage is applied during two intervals. The first interval precedes the collimator rotation, and the second interval follows the rotation.

Abstract: In a contour collimator for radiation therapy, a variable aperture is formed by two stacks of aperture plates, which are mounted opposite one another. The aperture plates are connected to a setting mechanism in order to alter the aperture created between the opposed aperture plates. All the aperture plates of each stack are arranged on a respective axle. The aperture plates can be rotated individually around the axles and into the aperture.

Abstract: In a radiation emitting device, particularly in a radiation therapy device, isodose curves are adjusted both by a moveable plate that is controlled during irradiation and by varying the dose rate of the radiation beam during irradiation. By superimposing the effects of moving the plate and varying the dose rate of the radiation beam, it is possible to vary the isodose curve in the object of irradiation, so that a wide range of variation in the possible isodose curves is obtained. If the plate is moved at a constant speed, e.g. various wedge-shaped isodose curves can be easily achieved.

Abstract: A radiation treatment apparatus is provided which has an extendable imaging device. The radiation treatment apparatus comprises a stand which supports a gantry in a rotable manner. The gantry has a treatment head for emitting a radiation beam towards an object. The extendable imaging device is coupled to the gantry opposite to the treatment head in the trajectory of the radiation beam at a point past the object. The imaging device includes an holding means which is extendable from the gantry one end of which is arranged at the gantry and at the other end of which a detector head is coupled. The detector head comprises an image converting means which in its operating position is essentially perpendicular to the radiation beam and which converts an image represented by the radiation beam into a visible image. It also comprises a reflector coupled with the image converting means for reflecting the visible image into a light channel formed by the holding means and to a video camera.

Abstract: The generation of excessive electron radiation is prevented in an apparatus which comprises an accelerator means for generating and accelerating electrons. The accelerator comprises an electron injector for emitting injector pulses, an electron gun for receiving the injector pulses, a waveguide receiving electrons from the electron gun and a high frequency source for supplying RF signals for the generation of an electric field for accelerating the electrons in the waveguide and generating the electron beam which has a predetermined intensity level according to the amplitudes of the injector pulses. A sensing means senses the amplitudes of the injector pulses and generates sensing signals. The amplitudes of the sensing signals are compared with predetermined reference voltage values and the generation of the electron beam is prevented if the amplitudes of the sensing signals exceed the predetermined reference voltage value.

Abstract: In a radiation therapy device isodose curves are adjusted both by a movable plate that is controlled during the irradiation and by a non-movable filter body in the radiation path. The filter body is located in such a manner that it has decreasing absorbability in the opening direction of the plate. On the other hand, the plate produces a decreasing effective dose in its opening direction. by superimposing the two effects, it is possible to have the isodose curve in the object of irradiation rise or fall in the opening direction, so that a wide range of variation in the possible isodose curves is obtained, without having to change the fixed filter body.

Abstract: The generation of excessive electron radiation or X-ray radiation is prevented in an apparatus which comprises an accelerator means for generating and accelerating electrons. These electrons form an electron beam which has a predetermined low intensity level for the generation of electron radiation or a predetermined high intensity level for the generation of X-ray radiation. In case of generating electron radiation a scattering foil or a target, respectively are arranged in the trajectory of the electron beam. The foil and the target are movably arranged on a support means.

Abstract: Apparatus for accelerating and transporting a charged particle beam. The apparatus has a housing which encases an accelerating structure as well as a magnet system. The accelerating structure accelerates an injected charged particle beam within a first evacuated space and directs the beam into the magnet system which transports it along a bent beam path within a second evacuated space. Both spaces are separate from each other and the magnet system is supported within the housing such that it can be angularly adjusted with respect to the accelerating structure. In a preferred embodiment, the second evacuated spaced is partially defined by magnet poles of the magnet system and filled with helium under a pressure of higher than 10.sup.-2 torr.

Abstract: An apparatus for generating and transporting a charged particle beam. The apparatus has a source which generates the charged particle beam at two current levels, and a magnet system for bending the beam. Particles of different energies are bent along different paths, whereby at a specific height within the magnet system the radial displacement from the beam axis is a monotone function of the difference between the energy and the nominal energy. At this height there is provided an energy selection filter having at least one bimetallic element. This element projects into the beam and, thus, intercepts beam particles; it is designed such that its interception distance decreases with increasing beam current. As a result, the energy range of particles passing the filter is broader at the higher current level broader than at the lower current level.

Abstract: A transmission ion chamber assembly for detecting the lateral displacement of an ionizing beam has two ion chambers located one behind the other along the beam axis. Each chamber contains two electrode plates and a spacer which separates and electrically insulates the electrodes from each other. The electrodes of each chamber are inclined with respect to each other along a preselected measuring axis. The axes of both chambers are perpendicular to the beam axis and to each other. In operation, the collector electrodes furnish current signals which depend upon the position of the beam along the associated measuring axis. With orthogonal chambers, i.e. measuring axes, the beam position in a plane perpendicular to the beam axis can be determined and aligned, e.g. via beam steering coils surrounding the beam.

Abstract: Method and apparatus for developing an estimation of the velocity of a moving target, comprising, transmitting groups of pulse signals towards the target, receiving groups of echo signals caused by reflections of the transmitted groups of pulse signals from the target and spatially processing the echo signals for developing the estimation of the velocity of the target. In a preferred embodiment, the spatial processing is for only a single pair of adjacent ones of ultrasonic echo signals and the estimation developes a two dimensional image of blood flow velocities in the body of a patient.

Abstract: A method and an apparatus for irradiating a relatively large area with a charged particle beam. In the method, a pencil-like beam is generated and spread along a fan axis perpendicular to the beam axis. The fan axis is rotated around the beam axis so that finally a circular area is irradiated. The apparatus includes means for generating a pencil-like beam, a lens system for spreading the beam along the fan axis and means to rotate the fan axis around the beam axis. In a preferred embodiment, the beam is spread such that its transverse intensity distribution increases with increasing distance from the beam center so that the area swept by the beam is irradiated with an even intensity.

Abstract: A target assembly for an electron linear accelerator (LINAC), comprising a target for converting electron beams of different energies into x-ray beams. The target has a variable thickness which can be set to a predetermined value by adjustment means. In a preferred embodiment, the target is provided with a chamber defined by two parallel plates and a bellows connecting both plates. The chamber is filled with a liquid medium of a high atomic number, such as mercury. In operation the medium is pumped through the chamber, and cooled down in a heat exchanger.

Abstract: A filter adjustment system for use in electron accelerator and the like includes a plug-shaped ring which engages the filter and is tiltably plugged into an immobile element.

Abstract: An electron accelerator unit comprises a source of an electron beam and means for finally directing at least a portion of the beam to a therapy site. The directing means is mechanically independent of, and electrically isolated from, the source of the electron beam.In the preferred embodiment, means are provided for aligning the source and the directing means using beams of light which are directed towards a target area on the directing means.

Abstract: A device for positioning a flattening filter in the center of an x-ray radiation, which comprises a drive means for driving the flattening filter between positions outside and inside the x-ray radiation; and a stop means for restricting the inside movement of the drive means to the center position of the flattening filter.

Abstract: An ultrasound diagnostic apparatus for displaying two-dimensional blood flow information superimposed over anatomical information. A transducer generates a series of ultrasound bursts which are directed towards the area of the body where blood flow and anatomical information are desired. The bursts are transmitted in several beam directions so as to form a sector scan. A receive interval follows each burst at which time the transducer detects ultrasound reflected from body structure and blood. A detector circuit receives the reflected ultrasound signals and produces a frequency difference signal which corresponds to the difference in frequency between the transmitted and reflected ultrasound, such difference being attributable to the Doppler shift produced by moving blood cells. The detected difference frequency data are forwarded to a processor unit which generates velocity estimator data for various points along each of the beam directions.

Abstract: A patient treatment table has a base and a table plate upon which a patient may be positioned. A spine having two bars supports at least one part of the table. The bars are so mounted that they may be shifted towards and away from each other beneath the table plate while keeping the table plate unmoved.

Abstract: An ionization chamber for measuring the profile of a radiation field is provided which comprises a first electrode and a second electrode arranged parallel to said first electrode, both electrodes forming a gap therebetween. A shield made of a material opaque to ions produced by the radiation field is movably arranged in said gap between said electrodes and has an aperture, which between said electrodes forms a measuring volume. The ionization chamber further comprises means for moving said shield together with said aperture along said gap between said electrodes.