Search PubMed⌕ Search

Biomedical subjects

H Röthig

Publications and source records attributed to H Röthig.

5 recordsLinked to original sources
PubMed1997

Acute response of pig skin to irradiation with 12C-ions or 200 kV X-rays.

The acute response of pig skin to treatment with high energy carbon ions (plateau region) at the Gesellschaft für Schwerionenforschung (GSI, Darmstadt, Germany) was compared with changes after 200 kV x-irradiation. Carbon doses isoeffective to the x-ray doses were computed with a recently established model for calculation of the biological effect of heavy ions. Clinical changes and physiological symptoms (blood flow, erythema, trans-epidermal water loss, skin hydration) were scored. The parameters analyzed were maximum and mean values of each symptom during days 24 to 70 after irradiation, and the quantal endpoints for the establishment of dose effect curves were the median values of these. With exception of the maximum change in the red blood cell concentration (p < 0.02) no significant differences could be found in the response to x-rays and RBE-corrected heavy ions. These results indicate that the model is valid for the calculation of biological effects of 12C-ions (plateau region) and may at least for epidermis be applied to treatment planning.

Animals↗
PubMed1995

[Experience in dealing with artificial pacemaker patients during therapy with ionizing radiation].

BACKGROUND: During radiotherapy the pacemaker-patient is exceptionally endangered by ionising radiation, because a damaging impact on the pacemaker's circuit is possible. PATIENTS AND METHODS: Guided by experiences of long standing dealing with pacemaker-patients during radiotherapy in our medical centre, we demonstrate possibilities to accompany these patients with well coordinated interdisciplinary co-operation. So the possible risks by ionising radiation can be identified and restricted. Our investigations on explanted pacemakers will explain the influence on programmable pacemaker systems. Standard values for the dose of 9-MV-photons will be recommended. RESULTS: The radiation dose, the pacemaker system is exposed during radiotherapy, should be kept as small as possible by suitable methods (e. g. shielding, selection of radiation quality, shifting of the pacemaker system to a region of less doses), to ensure that the functions and the duration of life is not effected. Because of the different manufacturing technologies and the scattering of the product parameters within a homogeneous set of pacemakers we are not able to specify a guaranteed value for the radiation resistance. CONCLUSIONS: The doses of pacemaker should be as minimal as possible. The patient's pacemaker system has to be controlled in adequate periods, in particular during radiotherapy. If the accumulate dose on the pacemaker system exceeds 5 Gy despite of all efforts, the pacemaker should be exchanged after the radiotherapy.

Female↗
PubMed1990

[The functional efficiency of cardiac pacemakers as affected by ionizing radiation].

Influence of functions of cardiac pace-makers by ionizing radiation are represented, that is characterized in praxis relevant parameters as pulse duration and sensitivity in a special clear manner. For these parameters dose limits were defined in a phantom where tolerance ranges of pace-makers, guaranteed by producer, were over or underdosed. These dose values were different in dependence of installed electronic wiring diagrams. The radioresistance of pace-makers with Lewicki-wiring diagram (MCP 211 L) was higher than those with wiring diagram U 115. Measurings showed that the upper dose limits were greater than the known values with 60Co- and 9-MV-roentgen braking radiation and with that the complete programming and functional capacity of the pace-makers were conserved. The close cooperation of radiologists, physicists, cardiologists and technicians in the implantation clinic guarantees a good care for patients with pace-makers during radiotherapy without complications.

Humans↗
PubMed1990

[A universal verification and protocol system for teletherapy].

To increase the quality of radiotherapy a verify and record system (VPS) was developed for teletherapy equipments, that takes control of manually adjusted irradiation parameters and of recording all relevant data of radiotherapy. The VPS can be adapted to special wishes of the user and it lends itself to application on different irradiation equipments. In the represented paper especially the extent of efficiency of the system is shown which is characterized by high operating comfort, flexible reacting to exceptional cases and by high date and operating security. The testing phase on an accelerator model has been brought to a close, actually the system is installed to an electron linear accelerator "Neptun 10p" and led to clinical trial.

Humans↗