No abstract available

[en] Issues of corrosion and corrosion protection in cooling circuits were the subjects of the 5th Korrosionum held at Iserlohn in March 1990. This volume contains the results of the conference. The authors discuss problems originating largely from corrosion, deposition and microbiological activities in cooling circuits. None of these subproblems is dealt with in isolation, the author make it a point to never lose sight of the complex interactions between these impacting factors. Based on the special technological aspects of methods, processes and materials in cooling circuits, corrosion issues are defined and corrosion protection options are discussed. For the first time, the microbiological processes relevant to corrosion and operation are demonstrated in a clear way, and major environmental aspects are discussed which result from the application of chemicals in cooling-water treatment. This book is intended as a source of information and knowledge for the manufacturers and operators of cooling circuit systems and as a means towards an in-depth understanding of the interactive correlations for engineers and technical staff concerned with operation, maintenance and water treatment. Out of the total of 11 papers, 5 have been entered separately into the 'Energy' database. (orig./MM)

[en] Following explanations on the radiation exposure to patients, which are supplemented by data in tables, the sensitivity of the patient exposure to technical as well as organisatorial parameters is gone into. Single points such as the influence of the tube voltage, the distance, field size, filtration, object thickness, intensification foils as well as examiner experience and training are briefly explained. The radiation exposure to the examiner as well as patient dosimetry are dealt with. (ORU/LH)

[en] A survey on the biological effect of X-radiation is given. Starting with the primary physical and chemical radiation effects, the relationship between linear energy conversion powers and relative biological effectiveness is explained. The usual methods in radiobiology to determine the radiation effects and their time development by means of dose curves is described and their practical significance in the radiotherapy of tumours is indicated. (ORU/LH)

[en] Following a brief description of the apparatus used to produce X-rays and their components, the common X-ray tubes in diagnostics and therapy as well as the X-ray generators belonging to these are explained. Likewise, switchboards and other equipment parts such as screening systems and filters as well as their principle of functioning are shown. The image formation system and the geometric conditions of the X-ray images are dealt with in two chapters. Finally, a description of various special investigations in X-ray diagnostics is given. (ORU/LH)

[en] Purpose/Objective: To assess the prognostic factors and treatment results of thymoma with emphasis on surgery and radiotherapy. Materials and Methods: Thymoma patients treated at Duesseldorf University Hospital from 1954 to 1991 were studied in this retrospective analysis. Depending on stage and residual disease, treatment was surgery (sternotomy or thoracotomy) with and without radiotherapy and chemotherapy (Holoxan, Endoxan, Vinblastin, Adriamycin, Bleomycin, CDDP, Vepesid). 70 patients (38f, 32m) were enrolled in this study. The mean age was 46,5 years. At presentation the median Karnofsky's index was 90%. In 19% thymoma was accidentally diagnosed, 81% presented symptoms at diagnosis. Masaoka's staging system was used (I: intact capsule; II: invasion of the capsule; III: invasion of neighboring organs; IV: dissemination). Stage at presentation was I:21%; II: 26%; III: 43%; IV: 10%. All histologic slices were peer reviewed. Histologic classification according to Lewis (predominantly lymphocytic: 36%; predominantly epithelial: 23%; mixed type: 33%, spindle cell thymoma: 9%) was applied. All available paraffin embedded specimens (36) were studied with DNA cytometric analysis after Feulgen staining. Occasionally thymoma was accompanied by Myasthenia gravis (23%) or other paraneoplastic syndromes (19%). Statistical analysis was performed using the Kaplan-Meier method and logrank-tests. Multivariate analysis was also performed. Results: From 70 patients treated surgically, 68% were radically resected (R0), 26% incompletely resected (R1,2) and 6% had biopsy only. The median cause specific survival (CSS) was 132 months. All patients with localized disease (stage I and II) were completely resected and received no further therapy, whereas only 50% (15 pat) in stage III and 0% in stage IV were amenable to radical resection. 36% (25 pat) received an additional therapy (CMT): 31% (22 pat) postoperative irradiation and 4% (3 pat) combined radio-chemotherapy. The radiation dose ranged from 40 Gy to 58 Gy. 50% (21 pat) of the completely resected patients without additional CMT relapsed (by stage: I= 7%, II= 62%, III= 86%), but only 1 (20%) of the 5 completely resected patients with CMT. 66% ((8(12))) of the incompletely resected patients with CMT relapsed, 27% within the irradiated volume. In stage III the CSS was 85 mo. after incomplete surgery and CMT versus 115 mo. after radical resection alone (p=0.72, n.s.). The DFS accounted to 45.7 vs. 44.9 mo. (p=0.36, n.s.). In addition Karnofsky's index did not significantly influence the overall survival (OS). Depending on histology the DFS was significantly better for lymphocytic type in comparison to the epithelial type (p<0.01). Myasthenia gravis did not influence the OS and DFS. DNA index was correlated with stage and DFS, but not with OS. Conclusions: The most important prognostic factor (PF) was stage according to Masaoka's staging system. CSS and DFS were both significantly influenced. The traditional histologic subtyping according to Lewis proved to correlate with DFS, with spindle cell type bearing the most favorable prognosis. The impact of CMT on treatment outcome is demonstrated in stage III, where incomplete resection plus CMT achieves long-term results comparable to radical surgery alone

[en] At the 6th Corrosion Meeting in Frankfurt, selected experts described the state of knowledge of the materials and corrosion protection systems of flue gas purification systems in powerstations, waste incinerators and sludge combustion plants, including the steel chimneys after combustion plants. The author's work in this Meeting Handbook is divided into basic information on the materials and corrosion protection systems used and the representation of practical experience from the last ten years, with consequences for the future. (orig./HP)

[en] The measuring set up of the computer tomograph is moved in such a way that the object to be examined is scanned from different directions. The computer calculates the absorption values of image points in longitudinal direction with respect to the object and thus also with respect to the bed. The axis of revolution is vertical to the longitudinal direction, the scanned region of layers being thus only penetrated by rays whose path through the object is crossed by a multitude of other radiation paths along its total length in the object. (RW)

[en] An analysis of a pilot study of neutron therapy of 70 patients with soft-tissue sarcomas is presented. In a group of 50 patients who had undergone macroscopically or microscopically subtotal surgery, 39 (78%) were free of recurrence after a mean follow-up period of 16.3 months (range: 7 to 33 months). In another group of 20 patients who had had partial tumor resection or only biopsies with gross tumor residual, local tumor control has been observed in 7 cases (35%). Despite these favorable results, there is as yet no evidence that neutron irradiation is superior to photon or electron irradiation in the postoperative treatment of soft-tissue sarcomas. To clarify this question, an EORTC/RTOG trial is being prepared

[en] In the exemplary embodiments a layer is to be scanned which is generally parallel to the longitudinal axis of the patient support. For example, a radiation source and a radiation receiver may be rotated in an arc about a rotational axis which lies perpendicular to the longitudinal axis of the patient support to scan a layer area in such a way that the scanned layer within the exposure subject is traversed exclusively along beam paths each of which is crossed along its entire length in the subject by a multitude of other beam paths