Radiobiologia, radiotherapia最新文献

The application of hyperthermia in tumor therapy is expanded to a high degree. As affecting point in biological tissue the following is discussed: Cytotoxic effect with temperatures of 43 degrees C with alterations on cell membrane and in intermediate metabolism, injury of microcirculation, where--because of a pathological vascularisation--tumor tissue is affected in a stronger way than the better adapted vessel net of normal tissue. The radiosensitizing effect between 40 and 42 degrees C is of interest for radiologist. Degree and duration of temperature and the interval between irradiation and thermal application modify the amplifying thermal factor. As adjuvant therapeutic modality the hyperthermia can decrease the hypoxic radioresistant part of cells and is an additional palliative therapeutic measure. Indications within a curative radiotherapy are elaborated at present globally.

At a model of initial immunoresponse of mice to sheep erythrocytes the immunostimulating activity of lipopolysaccharide (LPS) and dextransulphate (DS) was tested. It was shown, that suppression of the immunosystem after influence of radiation can be compensated successfully by application of lipopolysaccharide and dextransulphate. The prophylactic application of these preparation is more ineffective.

Tritiated water (HTO) injected intraperitoneally to Swiss albino mice at the rate of 370 kBq (10 microCi)/g body weight has been found to cause certain alterations in blood parameters 1, 5, 7 and 15 days postinjectionem. Leucocyte count dropped significantly post treatment. Differential leucocyte counting showed lymphocytes to be most affected which were reduced by 38.29% on 5th day p.i. Erythrocyte count, haemoglobin and haematocrit values though showed no significant changes at early intervals, these values were significantly lower at later intervals than those of control.

Despite the advanced treatment methods now available, the total result in 5-year survival is 40-50% of all patients with malignancies and 20% of these patients will have the chance of a 10-year survival. In the course of their disease a radiotherapy is indicated in about 2/3 of all cancer patients. Thus, radiotherapy makes quite a considerable contribution to the qualitative improvement of the treatment of patients with malignancies. Eradication of the tumor and protection of normal tissue can be only a compromise between tumor control and the production of complications. For the risk assessment of radiotherapy, the steepness of dose-response curves is of paramount importance. That means, small errors in defining and delivering dose can have catastrophic results in terms of failure to control the patient's disease and, on the other side, in terms of complications, that means in quality of life. Although the costs of therapy, in absolute values, vary from one country to the other, it can be stated in rough approximation that a failed radiotherapy will make rise the costs by a factor of 3. Proceeding on the fact that in 30-40% of patients, who received radiotherapy, the initial treatment failed to control the primary disease, the enormous additional costs involved become obvious, not to speak of the main argument--the regrowth of the patient's tumor. For the improvement of this situation quality assurance (QA) is an essential prerequisite, which should be guaranteed in all successive steps of radiotherapy. In the paper an analysis is given for all individual steps in the chain of radiotherapeutic measures.(ABSTRACT TRUNCATED AT 250 WORDS)

Actually CT-cross-sections are the best base for irradiation planning. Bases are represented to use CT-picture matrices of scanner TOMOSCAN CX (Philips) for irradiation planning. The direct application of CT-pictures is done in "off-line"-running with the magnetic tape set. For figuring on colour display and estimation of density matrix limits of Hounsfield values are given. Adjustment of the CT to take off scan planes requires a special work-regime for irradiation planning. Repair and use of defective CT-pictures are realized by input of specific outlines. In daily routine the output of sagittal dose distribution is most advantageous in form of a table. Application of this CT-irradiation planning system, being implemented on microcalculator K 1630, is shown for telecobalt irradiation of mammary carcinoma.

Retrospectively the patients were analyzed, postoperatively irradiated because of a hypernephroidal kidney carcinoma during the years 1978 to 1988. With a total number of 44 patients 12 were in stage I (Robson), 13 in stage II, 17 in stage III and 2 in stage IV. The probabilities for a tumor-free survival of five years were 81%, 59% and 30% for the stages I to III. The local recurrence rate was 7%, caused by exclusion of clinically negative lymph-nodes from irradiation field. In addition to survival probabilities the complication rate of radiotherapy is analyzed too. To this additionally to analysis of symptoms of a possible side-effect the nuclear medical investigation of function of the remaining kidney was done in 9 selected tumor-free patients being irradiated in different techniques. A normal function was found in all cases. No severe side-effects can be shown in irradiated patients. Consequently the postoperative radiotherapy in hypernephroma is a supportive therapy of advanced tumor stages without severe side-effects. Further and greater planned analyses are necessary to comprehend prognostic factors.

In a prospective analysis the effectiveness of roentgen irradiation with minimal doses (daily single doses .03 Gy up to a total dose of 1.5 Gy) was investigated in 207 patients with an epicondylitis humeri. Compared with a group of 92 patients, who were irradiated with higher doses being in general use (weekly 2x single doses 1.0 Gy to a total dose of 4.0 Gy), the therapeutic results show no significant differences. After termination of the first irradiation series an improvement of complaints was seen in half of the patients (48.8% or 50.0%). A further increase of the quota in success to 74.9% or 70.6% was found 6 weeks after termination of irradiation. By reason of radiotherapeutic results, mainly attained in chronic states of epicondylitis humeri after primary conservative therapy without success for months and partly surgical pretreatment, the radiotherapy should be used more frequently than till now, especially in consideration of its slight side-effects and injuries of patients.

The N-acetylneuraminic acid (N-ANA) concentration of serum in 24 patients with bladder carcinoma was measured with a modified Arzneibuch (D.L.) GDR-method before, during and after the postoperative radiotherapy. It was found that the N-ANA-concentrations in the patients operated resulted in a dependence from tumor staging already before the radiotherapy. The N-ANA concentration rose with increased staging. A temporary enhancement of the N-ANA-concentration with the maximum between 20. and 25 radiation fractions occurred in patients of staging T3 and relapses as well as with tumor cells being only little differentiated. The results are discussed in relation to the clinical importance.