Abstract: A radiation therapy system has a radiation therapy planning CT system and a radiation therapy apparatus. The CT system includes a system control unit, a CT scanner unit, and a therapy planning portion. The collected data obtained by the CT scanner unit is output to the therapy planning unit. The therapy planning portion creates therapy planning data such as center projection images for when performing therapy and center projection images for when performing X-ray photography. On the other hand, the radiation therapy planning apparatus includes a central control unit, an apparatus proper, and a driving control unit. The driving control unit controls in real-time the period of irradiation of radiation based on the therapy planning data from the CT scanner unit 34 and the opening/closing of the collimator 97, according to the position of the marker 9 on the fluoroscopy image photographed by the X-ray TV.

Abstract: In order to obtain a linear electron accelerator having enhanced beam performance, a thermion emitting face 11 of a cathode 10 is enclosed by carbon 17. Consequently, distribution of an electric field 30 for leading out electrons becomes parallel with the thermion emitting face 11. Therefore, electron beams emitted from the thermion emitting face 11 become streamlines parallel with each other. Thus, the beam performance of the linear electron accelerator can be enhanced.

Abstract: A water temperature gauge includes a first timer circuit in which a time for submerging the water temperature gauge to a position of a desired depth for measurement, and a measuring circuit for measuring the water temperature with the water temperature gauge after a lapse of the time set in the first timer circuit. A time which is obtained by adding a time required for the measuring circuit to measure the water temperature to the time set in the first timer circuit is set in a second timer circuit so that the measurement with the measuring circuit is automatically terminated after a lapse of the time set in the second timer circuit and the as-measured value is stored in a memory circuit and displayed on a liquid crystal display. A fisherman can confirm the underwater temperature of his fishing place by lifting up the water temperature gauge on the water surface and recognizing the display.

Abstract: A microwave electron gun for a linear accelerator uses microwave energy to impart an initial acceleration to electrons emitted from a lanthanum-hexaboride cathode. The microwave are contained in an electron-gun cavity, the upstream wall of which has a protruding part surrounding the entrance opening that accommodates the cathode, and the downstreams wall of which has a flat part surrounding an exit opening. The rest of the downstream wall has a radius of curvature equal to that of the other microwave cavities in the accelerating tube, and its center of curvature is aligned with theirs. The cathode is fused to a pair of carbon electrodes to form a cathode block, which is held by clamping between a pair of electrode bars, thus forming a cathode tube. The cathode tube is inserted into a sleeve upstream of the entrance opening in the electron-gun cavity, and is surrounded at a distance of one quarter-wavelength from the cathode by a disk-shaped choke cavity extending one quarter-wavelength from the cathode tube.

Abstract: A microwave electron gun for a linear accelerator uses microwave energy to impart an initial acceleration to electrons emitted from a lanthanum-hexaboride cathode. The microwaves are contained in an electron-gun cavity, the upstream wall of which has a protruding part surrounding the entrance opening that accommodates the cathode, and the downstream wall of which has a flat part surrounding an exit opening. The rest of the downstream wall has a radius of curvature equal to that of the other microwave cavities in the accelerating tube, and its center of curvature is aligned with theirs. The cathode is fused to a pair of carbon electrodes to form a cathode block, which is held by clamping between a pair of electrode bars, thus forming a cathode tube. The cathode tube is inserted into a sleeve upstream of the entrance opening in the electron-gun cavity, and is surrounded at a distance of one quarter-wavelength from the cathode by a disk-shaped choke cavity extending one quarter-wavelength from the cathode tube.

Abstract: A RF electron gun, such as for use in a linear electron accelerator, having a cathode activating device which, in one embodiment, includes means for altering the phase of the accelerating electric field to accelerate emitted electrons in the reverse direction to cause them to strike the cathode, thereby activating the cathode. In another embodiment, laser light is directed onto the cathode for activation thereof and, in a further embodiment, the electric field is positioned and directed at the cathode to cause the activation thereof.

Abstract: A method and apparatus for positioning a therapeutic beam in which a first distance from a first predetermined position other than an affected part of a patient to the affected part, is determined on the basis of a first image which includes at least part of the patient and which includes the position of the affected part of the patient. A second distance, from a second predetermined position corresponding to the first predetermined position to a position of the therapy beam, is determined on the basis of a second image which includes at least part of the patient and which indicates the position of the therapy beam. The patient is then moved such that the therapy beam is irradiated onto the affected part, on the basis of the first distance and the second distance.

Abstract: A microwave electron gun for a linear accelerator uses microwave energy to impart an initial acceleration to electrons emitted from a lanthanum-hexaboride cathode. The microwaves are contained in an electron-gun cavity, the upstream wall of which has a protruding part surrounding the entrance opening that accommodates the cathode, and the downstream wall of which has a flat part surrounding an exit opening. The rest of the downstream wall has a radius of curvature equal to that of the other microwave cavities in the accelerating tube, and its center of curvature is aligned with theirs. The cathode is fused to a pair of carbon electrodes to form a cathode block, which is held by clamping between a pair of electrode bars, thus forming a cathode tube. The cathode tube is inserted into a sleeve upstream of the entrance opening in the electron-gun cavity, and is surrounded at a distance of one quarter-wavelength from the cathode by a disk-shaped choke cavity extending one quarter-wavelength from the cathode tube.

Abstract: This invention relates to a charged particle beam-dosimeter comprising an ionization chamber which produces an ionization current having a magnitude proportional to the dose of a charged particle beam, an operational amplifier which is connected to the output side of the ionization chamber, a capacitor which is connected in parallel with the operational amplifier, and a comparator which is connected to the output terminal of the operational amplifier, wherein charges are collected in the capacitor on the basis of the ionization current having flowed from the ionization chamber, and when the output potential of the operational amplifier has become a predetermined voltage, one pulse is generated so as to be counted and simutaneously to extinguish the charges stored in the capacitor.

Abstract: A radio frequency coil for nuclear magnetic resonance imaging comprises two annular conductors which are coaxially disposed at opposite ends of a prescribed axis and at least one pair of longitudinal conductor groups which are symmetrically disposed in parallel to the prescribed axis and extend longitudinally from one annular conductor to the other. Each longitudinal conductor group comprises a plurality of longitudinally-extending electrical conductors whose ends are secured and electrically connected to the annular conductors. The longitudinal conductors are preferably in the form of electrically conducting wires, tubes, or plates. The annular conductors can be in the form of one-piece rings or in the form of one or more pairs of arcuate plates which are electrically connected with one another and disposed about the prescribed axis in the form of a ring.

Abstract: A radio frequency coil for nuclear magnetic resonance imaging comprises at least one pair of arcuate H-shaped members which are disposed about a longitudinal axis so as to form a tube. A variable capacitor means for adjusting the resonant frequency of the coil is connected across the feeding points of the coil. A balanced feed circuit comprising a balanced impedance matching circuit and a balanced-to-unbalanced converter is connected across the feeding points. An unbalanced current from a transceiver is converted into balanced currents which are fed to the feeding points.

Abstract: A radio frequency coil for a nuclear magnetic resonance imaging apparatus comprises a plurality of arcuate, plate-like H-shaped members which are disposed about a common axis so as to form a tube. The flanges of adjacent H-shaped members are electrically connected. The web of at least one of the H-shaped members is cut in two at its midportion to form two T-shaped plates, and the legs of the T-shaped plates are connected by capacitive coupling in a manner which allows the capacitance to be varied. A conventional variable capacitor can be used to vary the capacitance. Alternatively, each H-shaped member is divided into two T-shaped plates with overlapping legs. A dielectric material is provided between the overlapping portions, and the capacitance is varied by moving the T-shaped plates with respect to one another in the longitudinal direction of the tube so as to vary the size of the overlapping portions.