[5-Iodo-2'-deoxyuridine in the assessment of the individual reaction of experimental tumors to irradiation]. / 5-Iodo-2'-dezoksiuridin v otsenke individual'noi reaktsii éksperimental'nykh opukholei na obluchenie.

C57BL/6 male mice bearing subcutaneously transplanted melanoma B-16 were used to study the applicability of 5-iodine-2'-deoxyuridine labeled with iodine 125 and 131 radionuclides to assess individual tumor response to radiation. The experiments using intact animals and those locally irradiated in the dose of 10 Gy revealed a correlation between excretion of the above-mentioned radioactive labels from tumor area and tumor growth rate for each mouse (correlation coefficient r = 0.93-0.97). 5-Iodine-2'-deoxyuridine excretion rate measurement can be used in express (24-48 hr) tests of individual tumor response to radiation.

[A method for assessing the radiation loads on personnel and patients in accident situations with gamma therapy apparatus]. / Sposob otsenki luchevykh nagruzok dlia personala i bol'nykh pri avariinykh situatsiiakh na gamma-terapevticheskikh apparatov.

The authors proposed drawing up maps of dose rate distribution under the conditions simulating patient's irradiation for each gamma therapeutic unit in order to estimate a degree of danger of excess irradiation of medical staff and patients during patient's evacuation resulting from a defective unit (incomplete closure of locks in distant irradiation and sources getting stuck in endostats in interstitial therapy). The timing of measures for evacuation of a patient from an emergency room made it possible to calculate accurately equivalent doses to which a radiologist, a technician and a patient were exposed.

[Effect of blood flow inhibition in tumors on the effectiveness of hyperglycemia and hyperthermia when used following radiation]. / Vliianie ingibirovaniia krovotoka v opukholiakh na éffektivnost' giperglikemii i gipertermii pri ikh postradiatsionnom primenenii.

The role of tumor blood supply inhibition associated with hyperthermia (HT) and short-term hyperglycemia (SH) combined with HT in enhancement of antitumor action of x-ray radiation was assessed in experiments on solid Ehrlich carcinoma in mice. It was shown that blood flow inhibition assessed by 133Xe clearance, and tumor growth delay were more pronounced after irradiation at a dose of 10 Gy with subsequent SH and HT at 43 degrees C for 30 min as compared to a dose of 15 Gy combined with HT at 44 degrees C for 30 min. Both schemes showed correlation between a degree of blood supply damage in some tumors and the efficacy of their therapy. The authors suggest a significant role of blood flow inhibition in tumors in postradiation HT and especially HT in a background of SH for increasing antitumor effect of irradiation. The assessment of tumor blood supply inhibition is possible to predict the efficacy of SH and HT in radiation therapy.

[Effect of x-irradiation on the kinetics of 5-iodo-2'-deoxyuridine in a tumor]. / Vliianie rentgenovskogo izlucheniia na kinetiku 5-iod-2'-dezoksiuridina v opukholi.

Within the interval of 0.25-168 h after intraperitoneal administration of 125I-iodo-desoxyuridine (IDUR) to mice with inoculated melanoma B-16 or sarcoma-180 the kinetics of a radionuclide label (RL) in both tumors was almost the same; the difference were of quantitative nature only. X-ray radiation resulted in an increase in the radioactivity change rate on the first section of the curves of RL clearance, plotted in semilogarithmic coordinates, in both tumors. Differences in the rates in the study groups of animals irradiated at doses of 2; 10 and 20 Gy and their distinctions from the control group were significant. Proceeding from the modern concept of IDUR metabolism a simple mathematical model has been devised where it is assumed that at the initial moment t = 0.25 h general radioactivity measured in vivo over a tumor, results from radioactivity incorporated in DNA which is constant for each irradiation regimen up to a certain time, and the radioactivity of iodide which is released from the body by the exponential law. A formula has been deduced associating the rate of a decrease in general radioactivity on the first segment of a kinetic curve of RL clearance with the level of the label incorporation in DNA. Thus, the applicability of RL IDUR was shown for establishing the quantitative relations between the proliferative ability of a tumor and an irradiation dose.

[125I-iododeoxyuridine in the reaction of experimental tumors to irradiation]. / 125I-ioddezoksiuridin v reaktsii éksperimental'nykh opukholei na obluchenie.

A study was made of the kinetics of 125I-iodo-desoxyuridine clearance after x-ray irradiation of experimental tumors sarcoma-180 and melanoma B-16 at doses of 2, 10, 20 and 40 Gy. Change in the level of radioactive label within the time interval of 0.25-48 h was approximated by exponential function (r2-0.92-0.98) or straight lines on a graph in the semilogarithmic scale. Their inclination angles differed significantly for the above doses. Correlations were obtained between the ratio of the rates of change of radioactivity in the irradiated and control tumors within the interval of 0.25-48 h after the administration of 125I-iododesoxyuridine and parameters which characterized growth of the above tumors in various irradiation regimens. The analytical expressions obtained are applicable to quantitative assessment of a tumor response to irradiation.

[Experimental evaluation of the role of blood flow inhibition in hyperglycemia-enhanced radiation damage to tumors]. / Eksperimental'naia otsenka roli ingibirovaniia krovotoka v usilenii giperglikemiei luchevogo porazheniia opukholei.

The authors provided experimental assessment of the role of the blood flow inhibition in enhancement of radiation injury to tumors using short-term hyperglycemia. Experiments on mice with Ehrlich solid carcinoma showed the dependence of a rise of the antitumor effect of preceding radiation induced by glucose and glucose combined with mexamine on a degree of the blood flow inhibition under the influence of these modifying agents. It was established that a considerable enhancement of radiation injury occurred but in such tumors where short-term hyperglycemia and mexamine decreased the blood flow level not less than 5-10 fold as estimated by 133Xe clearance. The results of the above experiments showed that noticeable inhibition of the blood flow in tumors was a necessary though, probably, not the only condition for a high efficacy of short-term hyperglycemia used as an adjuvant to radiotherapy.

[Dosage fields of the "ANET-B" apparatus with 252Cf]. / Doznye polia apparata "ANET-B" s 252Cf.

The paper is concerned with the results of the calculation of dose fields of neutron and gamma-radiation for an ANET-B unit. Experimental measurements were done in the tissue equivalent phantom by using photoluminescent and alumophosphate glasses, thermoluminescent and threshold detectors with neptunium foil. Divergences between calculated and all experimental data did not exceed 10-12%. It has been shown that the ratio of the contribution of neutron and gamma-components of 252Cf radiation for the ANET-B unit to the summary absorbed dose at an arbitrary point of a tissue equivalent phantom depends considerably on a distance between this point and the center of a source and changes from 2 (for a distance of 0.5 cm) to 1 (for a distance of 10 cm).

[Improved program maintenance of the CIRCIS dosimetric planning system]. / Usovershenstvovanie programmnogo obespecheniia sistemy dozimetricheskogo planirovaniia SIRTsIS.

A special computer complex CIRCIS (Informatique, France) is used in the All-Union Cancer Research Center, USSR AMS, for the dosimetric planning of radiotherapy on 5 gamma-beam units and electron accelerator. Mathematical maintenance of the complex includes programs of the calculation of dose distribution for gamma-, inhibition and electron radiation but has no program of the calculation of the time of irradiation. The authors have devised and introduced into the complex such a program in the Fortran language that makes it possible to calculate within 2-3 min the time of irradiation for multifield rotation therapy using several units as a time, thus expediting the dosimetric planning for patients' irradiation.