[en] A compact and accurate equation has been developed that describes the output field size over the range from 4 x 4 to 35 x 35 cm2. An accuracy of +/- 0.2% has been demonstated for teletherapy machines with energies from 250 kVp to 6 MV. The same accuracy down to a depth of at least 30 cm. The relationship is described by a hyperbola whose x and y axes are displaced by corresponding values X0 and Y0 producing the equation y = Y0 - C/(X0 + x), where y = output and x = field size. By substituting three separate values for y and x into three simultaneous equations, values for Y0, X0 and c can be derived

[en] Palliative therapy for previously irradiated patients with symptomatic recurrent endobronchial malignancy is a difficult problem. We have had the opportunity to treat 20 such patients with high dose rate (50-100 rad/min) endobronchial brachytherapy. Eligible patients had received previous high dose thoracic irradiation (TDF greater than or equal to 90), a performance status of greater than or equal to 50, and symptoms caused by a bronchoscopically defined and implantable lesion. The radiation is produced by a small cobalt-60 source (0.7 Ci) remotely afterloaded by cable control. The source is fed into a 4 mm diameter catheter which is placed with bronchoscopic guidance; it may oscillate if necessary to cover the lesion. A dose of 1,000 rad at 1 cm from the source is delivered. We have performed 22 procedures in 20 patients, four following YAG laser debulking. Most had cough, some with hemoptysis. Eight had dyspnea secondary to obstruction and three had obstructive pneumonitis. In 12, symptoms recurred with a mean time to recurrence of 4.3 months (range 1-9 months). Eighteen patients were followed-up and reexamined via bronchoscope 1-2.5 months following the procedure; two were lost to follow-up. All had at least 50 percent clearance of tumor, and six had complete clearance; most regressions were documented on film or videotape. In six, the palliation was durable. The procedure has been well tolerated with no toxicity. We conclude that palliative endobronchial high dose rate brachytherapy is a useful palliative modality in patients with recurrent endobronchial symptomatic carcinoma

[en] A large flat screen-low light level TV-fluoroscopic system having a 43 cm x 43 cm input screen has been used to monitor patients undergoing radiation therapy with megavoltage treatment beams. This article illustrates some preliminary results obtained for ⁶⁰Co and 6 Mv x rays. Portals covering the head, the supraclavicular region, the chest, and pelvic regions have been imaged. The live video images clearly show heart, lung, and diaphragm motion. Except in the pelvis, anatomical structures are clearly demonstrated. Permanent recordings are made either on video tape or video disk. The corresponding verification films are shown in each instance. Improved image quality can easily be obtained with improved hardware. The video images are easily enhanced by special analogue circuitry which is available at reasonable cost

[en] The JET ICRF A/sub 1/ Antenna Vacuum Transmission Lines will be pumped with individual non-evaporable getter pumps. The pump is a cartridge type in an all welded body which is heated externally to give activating, operating and regenerating temperatures. The pumped Hydrogen is periodically regenerated back into the torus. This will be particularly advantageous during the tritium phase of operation. The pump is simple and gives a high reliability. It is tolerant of conditions close to the torus and can be sited within the volume reserved for installation of the RF transmission lines. The all welded system simplifies remote handling. Tests on prototype pumps are being conducted to establish operational data and confirm contamination, saturation and embrittlement levels. A getter pump has been installed on one of the existing antenna systems on JET, no difficulties have been experienced in operating this antenna

No abstract available

[en] The JET ICRF A₁ Antenna Vacuum Transmission Lines will be pumped with individual non-evaporable getter pumps. The pump is a cartridge type in an all welded body which is heated externally to give activating, operating and regenerating temperatures. The pumped Hydrogen is periodically regenerated back into the torus. This will be particularly advantageous during the tritium phase of operation. The pump is simple and gives a high reliability. It is tolerant of conditions close to the torus and can be sited within the volume reserved for installation of the RF transmission lines. The all welded system simplifies remote handling. Tests on prototype pumps are being conducted to establish operational data and confirm contamination, saturation and embrittlement levels. A getter pump has been installed on one of the existing antenna systems on JET, no difficulties have been experienced in operating this antenna. (author)

[en] The electrostatic screens for the A/sub 1/, JET ICRF antennae are required to be water-cooled in order to extend the pulse length to 20 seconds. Whilst many features found beneficial in the uncooled (A/sub o/) antenna have been retained, the provision of cooling, improvements in shape and interfacing with the toroidal limiter have much increased the complexity. The screens are fabricated in high purity nickel and manufacture has involved the development of machining, forming and welding processes to obtain the required mechanical performance. Tests of samples, a short proof assembly and a prototype screen have qualified the design and manufacturing processes. Magnetic forces during disruptions are reduced by the use of resistive electrical contacts, and the screen cooling is also used to cool the antenna side protection between pulses

[en] The electrostatic screens for the A₁ JET ICRF antennae are required to be water-cooled in order to extend the pulse length to 20 seconds. Whilst many features found beneficial in the uncooled (Asub(o)) antenna have been retained, the provision of cooling, improvements in shape and interfacing with the toroidal limiter have much increased the complexity. The screens are fabricated in high purity nickel and manufacture has involved the development of machining, forming and welding processes to obtain the required mechanical performance. Tests of samples, a short proof assembly and a prototype screen have qualified the design and manufacturing processes. Magnetic forces during disruptions are reduced by the use of resistive electrical contacts, and the screen cooling is also used to cool the antenna side protection between pulses. (author)