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Biomedical subjects

A S Pavlov

Publications and source records attributed to A S Pavlov.

At least 37 records · Page 2Linked to original sources
PubMed1983

[Use of time-dose-fractionation models in planning the radiation treatment of malignant tumors].

New methods of the fractionation of preoperative gamma-beam therapy for breast carcinoma and intracavitary irradiation of cervical cancer patients with 252Cf fast neutron sources have been devised and tested on the basis of the concept of a cumulative radiation effect (CRE) and the system of TDF factors at the Chair of Clinical Radiology, Central Institute for Advanced Medical Training. In the selection of regimens of the fractionation of intracavitary irradiation of cervical cancer with 252Cf fast neutrons using the system of TDF factors one should take into account the RBE of the type of radiation that would be equal to 5 by the criterion of a direct response of a tumor within the range of dose rates between 20-30s Gy/hr. Taking account of a short period of half-life of 252Cf sources fractionation schemes should be corrected from the view-point of the system of TDF factors not less than once in 2-3 mos.

Brachytherapy↗
PubMed1983

[Effectiveness of prophylactic irradiation of the cervical lymphatics in malignant tumors of the nasopharynx].

The effectiveness of prophylactic irradiation of areas of the neck commonly involved in metastatic spread was studied in 276 patients with nasopharyngeal malignancies who were followed up during 5 and more years. The analysis was carried using such criteria as the decrease in the frequency of recurrent regional metastases, distant metastases and increase in 5-year survival. The absorbed doses ranged 45-50 Gy. The procedure was followed by a decrease in the frequency of regional metastases (3.4% versus 32.7% in untreated patients). The frequency of distant metastases decreased nearly by half (19.5% versus 31.7%). Five-year survival rates increased significantly from 49 to 65.5%. This relationship was recorded for all histological types of tumors. Application of prophylactic irradiation in doses of 45-50 Gy prevents local subclinical metastasis development in most patients.

Evaluation Studies as Topic↗
PubMed1981

[Cell proliferation parameters in human rectal tumors and their transformation during fractionated irradiation].

Human rectal adenocarcinoma is characterized by considerable variation in labelling index for different tumors as well as different areas within the same tumor. Therefore, the averaged indices of tumor cell proliferative activity do not mirror the actual heterogeneity of tumor. Conventional schedules of fractionated irradiation resulted in a decreased labelling index and varying response in most cases under study. Following large-dosage fractionated irradiation, labelling index remained unchanged or showed a slight decrease. The rate of DNA synthesis is practically unaffected by the available schedules of fractionated irradiation.

Adenocarcinoma↗
PubMed1980

[Prognostic factors of the probability of the occurrence of complications in the radiation therapy of malignant neoplasms].

The authors present an analysis of the causes of radiation induced complications in 383 patients referred to the Chair of Clinical Radiology from different medical institutions of the country. It was found that under distant gamma therapy, to prevent the development of complications the value of TDF-factor should not exceed 105--110, for the associated radiotherapy--130--140, and that for close focal roentgenotherapy--130--150. In vast majority of patients (95.3%) the complications resulted from surpassing the normal tissue tolerance. To prevent radiation injuries it is suggested to take into consideration the TDF-factor values, while in planning radiotherapy to choose such schedules of irradiation, which preclude any surpassing of the tolerance of normal tissues and organs adjacent to the tumor.

Humans↗
PubMed1978

[Role of radiation therapy in the complex treatment of breast cancer].

The survival rate in breast cancer patients depending on the radiotherapy method employed was analysed. Based on the longterm follow-up of 1385 patients, it is shown that of all the methods of radiotherapy the preoperative irradiation, including the primary tumor site and all zones of regional metastatic spread, seems to be most preferable. Postoperative radiotherapy is a less advantageous technic, and it may be in use in case of lymphnodes metastases and an evident violation of anablastic principles during the operation. An accessory use of chemotherapy would improve the prognosis for breast cancer patients.

Breast Neoplasms↗