Strahlentherapie最新文献

The effects of irradiation on the development of molars and incisors up to the age of 57 days was studied applying locally a single dose of 9.6 Gy of X-rays to the head region of eight-day-old female rats. Radiography of jaws revealed the absence of the third molar in all irradiated rats, as a result of germ stunting which was, at the moment of irradiation, in the phase of histodifferentiation. In the case of the first and second molar, being at the time of irradiation in the phase of root formation, changes were noted in the development and morphological features of the roots. In animals sacrificed 18 days after irradiation, the radiographs of jaws showed a break in the continuity of the incisors located under the mesial root of the first molar. In all animals the break in continuity of the incisors became macroscopically visible between the 28th and 42nd day after irradiation. 15 days after the loss of incisors, the incisival functional occlusion was restored in all animals.

The authors present the results of investigations of the immune reactivity of 72 patients irradiated for testicle tumors. The responses to tuberculin and DNCB (2.4-dinitrochlorobenzol) were examined before the treatment, within twelve months after radiotherapy and three years after radiotherapy and when metastases appeared. After radiotherapy, the number of positive responses was slightly decreased in both examination methods, but the difference was in no case significant. Patients with metastases showed a significantly decreased response to DNCB compared to the results obtained before radiotherapy. 5.6% of the patients had suffered from herpes zoster. The incidence of other infective diseases was not increased. The conclusion is drawn that the moderate immunosuppression caused by radiotherapy does not exert any influence on the further way of living of patients with testicle tumors.

A method for the electron irradiation of the body surface is presented which can easily be applied and standardized. The patient is placed in prone and supine position on the normal irradiation table. Contrary to many other methods, this proceeding is especially comfortable for the patient.

The authors applied the method of regrowth delay in order to investigate the effect of a therapy combination consisting of cis-platinum and irradiation on the fibrosarcoma SSK2 in C3H mice. An independent addition of the effects of both therapy modalities was found. It could be shown especially that no elective radiosensitization of hypoxic tumor cells is caused by cis-platinum.

From August 1978 through December 1980, 119 patients of previously untreated carcinoma of the uterine cervix were treated using RALS, remote afterloading high dose rate intracavitary therapy at our department. The data from 92 out of 119 patients were available for analysis of rectal complication. The incidence of major rectal complications was only 2% (2/92). Uni- and multivariate analyses were used based on the external criterion variable of rectal complication which included even minor injuries. By using these methods, it was clearly indicated that these factors such as TDF of rectum, Z-coordinate of weighted geometric center (WGC-Z), the dose of whole pelvic irradiation, history of chemotherapy and Treponema pallidum hemoagglutination test (TPHA) were important for occurrence of rectal complication. According to discriminant score, 71 out of 92 cases (77%) could be correctly discriminated.

The cytotoxic action of ionizing radiation can be increased by cis-platinum (CDDP) and its derivates. This effect is due to interactions in the cellular desoxyribonucleic acid (DNA), and it is especially marked in a hypoxic medium. A synergistic and an additive summation can be discerned depending on the type and dosage of the applied substance and the temporal relation between its application and irradiation. The radiosensitization of DNA before radiotherapy (RT) and the restriction of recovery processes after RT are considered as main mechanisms of this effect. A therapeutic potentialization of CDDP and RT could be demonstrated in a series of experimentations on animals. E.G. a therapeutic gain factor of 1.7, related to the sound surrounding tissue, was found out for the C3H mammary carcinoma during a series of in-vivo experimentations on mice. The applicability of a simultaneous treatment with CDDP and RT of human tumors depends on the systemic and local side effects of such a therapy. The results achieved hitherto in clinical pilot studies on advanced solid tumors situated above all in the head and neck area are at least equivalent to those of a sequential induction chemotherapy and subsequent definitive radiotherapy. They can possibly be improved by a further optimization of the temporal application and dosage of CDDP, but also by using other platinum derivates. It is not yet possible to describe any undesired long-term effects. However, the side effects observed hitherto in the irradiated areas are apparently of minor clinical importance.

A simple and cheap method is described for the manufacturing of individual positioning aids made of foamed polyurethane. Some examples are given to demonstrate the applicability of these positioning aids for the irradiation of different body regions. The reproducibility of the radiation field in the head and neck area was investigated with and without positioning aid. It was proved that the field is adjusted more exactly when positioning aids are applied. The dosimetric investigations performed showed a negligible influence of foamed polyurethane on the radiation quality. So the positioning aids could be left within the radiation field when drawing the field borders.

Twelve nephrectomized patients were examined by computed tomography in prone and supine position. The distances necessary for irradiation planning were measured in order to estimate which position is more favorable for irradiation. The advantages of prone position in comparison to supine position seem uncertain and do not outweigh its disadvantages.

Anatomical configurations often are an obstacle to a convenient dose-distribution in intracavitary afterloading irradiation. Multiple applicators (splay applicators, twin applicators) cannot be introduced in all cases because of the necessary cervix dilatation. In several cases can be demonstrated, that a defined intracavitary irradiation is possible only by hysterographic control of the intrauterine position of the applicator. By this control generally a mono-applicator is sufficient, which can be placed according the anatomy of the uterine cavity in each session. For this purpose a simple hysterographic method with applicator in position is demonstrated, which requires only few additional effort during intracavitary irradiation.

A brachytherapy by afterloading technique which would be adequate to the method of Stockholm, Munich, or Hamburg met with difficulties until the year of 1977, because there were no practicable afterloading probes in the form of plates. As for the charge of a radium plate in which radium tubes are joined together in different arrangements according to the technique applied, the probes of multiple probe units can be arranged in a parallel order, so that the effect of a radiation shield is produced. Plates made of plexiglas or of synthetic material in which the probes with the sources are inserted by corresponding boreholes serve as carriers for the afterloading probes. The dose to the points P, A and B, R and V is calculated taking into consideration the distance between the probe plate and the target volume, and the dose distribution is optimized by means of CT and of an irradiation computer. The irradiation of large tumor volumes can now be performed under the same conditions as for radium therapy. In our Department, the high dose-rate method is applied for this irradiation for colpostatic reasons. Between October 1, 1976 and December 31, 1983, 1272 patients were submitted to this treatment. A plate applicator which has satisfied all requirements was developed in 1981 in collaboration with the companies Buchler, Braunschweig and Chemomedica, Vienna.