[Use of 3-dimensional magnetic resonance tomography for radiation planning of circumscribed brain tumors].
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to A Atzinger.
Explore the source record for details and available documents.
Between 1960 and 1982, 90 patients treated primarily for peripheral soft tissue sarcomas received a postoperative irradiation at the Irradiation Department of the Städtische Krankenhaus Passau. Five patients (6%) were inoperable for internistic reasons and were treated only by radiotherapy. The local recurrence rate after combined therapy was 26%. 44% of the patients (40/90) developed metastases, preponderantly in the lung and within the first year (70% each). The age-corrected survival rate was 63% after five years and 43% after ten years in 79 patients with complete postoperative irradiation. Important prognostic factors are the degree of malignancy (five-year survival times of 57 patients: almost 90% for G1 tumors, 50% for G2 tumors, and 17% for G3 tumors, statistically significant) as well as the completeness of surgery. It is shown by the available results that conservative surgical interventions combined with radiotherapy are not less effective than more radical operations.
The moving-strip irradiation of the total peritoneal region plays an important role in the adjuvant therapy of the ovarian carcinoma. TLD dosimetric and mathematic investigations of this radiotherapeutic method show that 1. the best dose homogeneity in the longitudinal profile is achieved by 60Co units, if the patients are not too stout, 2. a higher relative depth dose has to be estimated than for an open field of the same total field size, 3. an additional 2,5 cm strip has to be inserted in order to achieve an abrupt drop on the border of the total irradiation field, 4. this method offers a good guarantee against false adjustment, if this is not too grave, 5. the conformity between the dose distribution curves calculated and those measured by TLD is excellent.
The article discusses initial experiences of NMR examinations of carcinoma of the uterus and cervix uteri (resistive magnet, NMR prototype of Siemens). All examined carcinomas show prolonged relaxation times. Variation of measurement parameters results in good optical presentation of carcinoma tissue in the resonance scans. The results are compared with those of CT-scans and in one case with the site of the operation.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
During a radiotherapy of ovarial carcinomas and other gynecologic tumors, special attention must be given to the reaction of the organs of urinary excretion as well as of the small and large intestine, especially if the irradiation is applied by the moving strip method or as an abdominal bain with an irradiation field comprising the whole abdominal and diaphragmatic region. The early and late radiogenic reactions of our great number of patients were routinely examined. A continuous control of the urinary excretion conditions before, during and after radiotherapy is absolutely necessary. These examinations are also of high relevance with regard to the early recognition of recurrences. An additional control of the rectum and sigmoid region is necessary with respect to late lesions. Regular ultrasonic or CT examinations are important in order to early recognize metastases in the preferred regions of formation of metastases which are hardly accessible by other methods (intraperitoneal dissemination with ascites, surface of the diaphragm, local extension, retroperitoneal lymph nodes, and transdiaphragmatic extension to the interpleural lymph nodes). Finally the authors present their first experiences with the NMR technique in radio-oncology and discuss the value of tumor markers in case of ovarial carcinomas.
Explore the source record for details and available documents.
Since 1976, radiotherapy planning is based on computed tomography in the Radio-Oncologic Department of the hospital of Passau. Every year we have about 1200 new tumor patients, 30 to 40% of them being submitted to an individual CT planning. So we are able to evaluate about 1000 cases of CT-planned radiotherapies. The single steps of CT planning are described. The position of the patient is an important factor for CT planning as well as for the subsequent irradiation. A topogram has been mounted on the tomograph in order to find out the best position and, in order to guarantee a precise reproduction of this position, identical laser systems have been installed on the tomograph and in the irradiation room. Some examples are presented in order to describe the mode of action of these devices. Furthermore, a new control method is presented which allows to check the accuracy of field screening by means of computed tomography.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The authors examine the combination of percutaneous and intracavitary irradiation using the afterloading system. The isodoses are directly superposed on the CT zone. Two examples of different positions are given in order to discuss possible overdoses or underdoses, the radiation exposure of bladder and rectum as well as the necessary shielding.
A critical look at the use of computed tomography (CT) for radiation therapy planning shows problems which all arise from incorrect positioning of the patient. CT is an excellent tool for therapy planning if the patient is positioned identically at the CT scanner and on the therapy couch. This is accomplished by installing matching laser systems at the CT scanner and at the therapy machine. The authors' planning procedure is discussed in detail.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A report is given on 24 thymomas irradiated between 1971 and 1980. Ten patients were irradiated after a radical thymectomy, three after partial resection and eleven after histologic diagnosis alone The patients were treated by different irradiation methods, mostly with the photons of a Co60 unit and a 43 MeV betatron. The average focal dose was 45 Gy which were administered within five weeks. The observation period was five years on an average. The general five year survival probability was 54%; some partial collectives were evaluated individually. These studies show that by unique radiotherapy, too, a two-year survival rate of 100% and a five-year survival rate of 50% as sell as a local recurrence rate of about 20% can be reached. Patients under fourty years with epithelial thymomas and a dose of less than 40 Gy have a less favorable prognosis. Compared to other authors, a relatively high rate of remote metastases was observed which necessitated extensive follow-up measures and suggests an adjuvant chemotherapy.
The results presented in this article lead to the conclusion that it would be appropriate to demand control or monitoring of radiation via CT whenever complicated exposure to radiation is required. Such control appears mandatory in order to guarantee a sufficiently high tumour dosage and satisfactory protection or minimum burdening of the surrounding tissue. At first sight, it may seem that such CT operations are relatively costly. However, once the teamwork has been properly established, both the time required and the cost involved remain within reasonable limits and will probably not be greater than control via therapy simulator. The decisive factor is that computerised tomography should offer sufficient possibilities of translating such control into reality by effecting the necessary dosage adjustments in accordance with given requirements.