[Ozone therapy for radiation reactions and skin lesions after neutron therapy in patients with malignant tumors].

The article discusses the problem of radiation complications from normal tissues in patients after therapy with fast neutrons of 6.3 MeV. The methods of treatment using ozone technologies in patients with radiation reactions and skin lesions on the areas of irradiation after neutron and neutron-photon therapy have been worked out. Ozone therapy showed its harmlessness and increased efficiency of complex treatment of these patients.

[Fast neutrons 6.3 MeV in the combined treatment of patients with local recurrence of breast cancer].

The article is devoted to the problem of treatment of patients with locally advanced breast cancer recurrences as well as a study of neutron therapy influence on normal tissues and various critical organs. The use of fast neutrons of 6.3 MeV in these patients is often the only treatment option. A 6-year survival rate of patients without repeated signs of recurrent breast cancer after neutron and neutron-photon therapy is 92.2 ± 5.7%.

[The use of fast neutrons in treatment of malignant tumors of the head and neck].

The article presents issues of the application of neutron therapy in the combined and radiation therapy for head and neck tumors. There were developed methods of neutron and neutron-photon therapy in pre- and postoperative periods as well as in stand-alone option in unresectable tumors. The data obtained clearly demonstrate the superiority of new ways over standard methods of treatment. Neutron therapy is satisfactorily tolerated and allows improving the results of combined and radiation therapy patients with malignant tumors of the head and neck.

Tomsk Polytechnic University cyclotron as a source for neutron based cancer treatment.

In this paper we present our cyclotron based neutron source with average energy 6.3 MeV generated during the 13.6 MeV deuterons interactions with beryllium target, neutron field dosimetry, and dosimetry of attendant gamma fields. We also present application of our neutron source for cancer treatment.

[Radiation-induced reactions in breast cancer patients after breast-conserving surgery with intraoperative and external beam radiotherapy].

The present study is aimed to evaluate the frequency and severity of radiation-induced reactions in patients with stage T1-2N0-1M0 breast cancer, who received intraopeartive radiation therapy (IORT) in combination with external beam radiotherapy (EBRT). A small-size betatron producing 6 MeV electron beam was used for IORT. External beam radiotherapy was performed using Rokus and Theratron machines. Radiotherapy treatment was planned using a specially devised method to ensure acceptable levels of severity and frequency of radiation reactions. The patients were divided into 3 groups: the study (40 patients), control (88) and comparison (50) ones. Radiation-induced skin reactions in the study group ranged from erythema to moist desquamation and edema. Magnetic laser therapy was used to treat radiation-induced injuries. The applied method of estimating the total dose of IORT and EBRT was shown to provide the acceptable levels of severity and frequency of radiation reactions.

[Dosimetric computer-assisted planning of therapy of malignant tumors with fast neutron beam of cyclotron U-120]. / Dozimetricheskoe kompiuternoe planirovanie terapii zlokachestvennykh opukholei puchkom bystrykh neitronov tsiklotrona U-120.

A method program were developed for computation of dosimetric characteristics of radiation fields in gamma-neutron irradiation of cancer patients. The program provided calculation of the distribution of isoeffective and absorbed doses and the time-dose-fractionation factor. Isodose charts could be obtained in the digital code or graphically.

[The integral radiobiological parameters for describing the reaction of heterogeneous tumors to ionizing radiation exposure]. / Integral'nye radiobiologicheskie parametry dlia opisaniia reaktsii geterogennykh opukholei na vozdeistvie ioniziruiushchim izlucheniem.

A new concept--integral radiobiological parameters--was introduced to describe features of a heterogeneous tumor. Introduced values were defined and their relationship with respective differential characteristics was established using mathematical expressions. The results of calculation of heterogeneous tumor regression, obtained with the help of integral and differential values, are well accorded. The results of investigation permit a wide use of radiobiological data for enhancing the efficacy of tumor radiotherapy.

[Dose fractionation in photon and neutron therapy in the combined treatment of osteogenic sarcoma]. / Fraktsionirovanie dozy fotonnoi i neitronnoi terapii pri kombinirovannom lechenii osteogennoi sarkomy.

The paper is concerned with the clinical testing of irradiation fractionation in photon therapy, of which the optimum variant was worked out using a method of mathematical simulation. It was conducted in 30 patients with osteogenic sarcoma. In 5 cases a course of photon therapy was supplemented by neutron irradiation. Good tolerance of the proposed scheme by the patients, the absence of contraindications for its administration and marked antitumor efficacy were revealed. Radiation pathomorphism of osteogenic sarcoma after photon and neutron therapy was described.

[A radiobiologic model for optimizing the radiotherapy of malignant tumors within the framework of the Ellis concept]. / Ein radiobiologisches Modell zur Optimierung der Strahlentherapie maligner Tumoren im Rahmen der Ellis-Konzeption.

A radiobiological model is represented, that allows to estimate the number of surviving tumor cells at the end of radiotherapeutic series with equivalent NSD. On this base a programme for computer-assisted calculation was elaborated. The programme allows to estimate optimal conditions of dose fractionation, in which a devitalization of a maximum number of tumor cells is guaranteed. For the radiotherapy of radioresistant tumors, characterized by the extrapolation number n greater than 2, optimal parameters can be obtained by means of simple mathematical formulas. The elaborated model allows to increase the efficiency in radiotherapy of malignant tumors with known radiobiological parameters.

[A method for calculating the distribution in biological tissue of an absorbed dose of a fast-neutron beam from the U-120 cyclotron]. / Metod rascheta raspredeleniia pogloshchennoi dozy piuchka bystrykh neitronov tsiklotrona U-120 v biologicheskoi tkani.

The author proposed a method for calculation of the distribution of an absorbed dose of a fast neutron beam on Y-120 cyclotron in biological tissue. The method ensured the coincidence of the results with average experimental data with the accuracy no less than 3%, and could be used for dosimetric design of cancer therapy with fast neutrons.

[The reaction of tumors and normal tissues to therapy with fast neutrons from the U-120 cyclotron]. / Reaktion von Tumoren und Normalgeweben bei der Therapie mit schnellen Neutronen am Zyklotron U-120.

In the present information results of clinical studies are represented to show the effectiveness of therapy with 6.3 MeV fast neutrons in 45 patients with superficial tumors in head and neck area. The reaction of tumor and of normal tissue was studied in dependence on different physical and biological factors. Two variants of neutron therapy planning were estimated by means of mathematical models of a factor of time-dose-fractionation for neutron (TDFN) from clinical point of view. Results of changes in oxygen-tension within the tumor are represented in 20 patients with metastases in cervical lymph-nodes during neutron therapy. The obtained data show a correlation of regression and reoxygenation rate of the tumor to its initial volume. The reaction of the tumor in therapy with fast neutrons was studied in dependence on its morphological structure. Complete regression of epidermoid and nonepidermoid cancer types was seen in 42 or 89% of the cases. With corrections for adipose tissue and the extent of dose fraction of fast neutrons the clinical test of the mathematical model of TDFN-factor made discernible that the reaction of normal tissue can be prognosticated quite exactly by means of this model in neutron therapy.

[Distribution of the relative biological effectiveness of fast neutrons according to the depth of the irradiated tissue]. / Issledovanie raspredeleniia otnositel'noi biologicheskoi éffektivnosti bystrykh neitronov po glubine obluchaemoi tkani.

A study was made of the dependence of relative biological effectiveness (RBE) and isoeffective dose of fast neutrons (produced by U-120 cyclotron) upon the depth of the exposed tissue. It was shown that the isoeffective dose and RBE vary significantly with the depth of the tissue-equivalent medium. The investigations were carried out with the purpose of improving the radiobiological and dosimetric techniques for the treatment of malignant tumors using a neutron beam from U-120 cyclotron.

[The use of a time-dose-fractionation model for stepwise control of radiotherapy of malignant tumors]. / Primenenie modeli vremia-doza-fraktsionirovanie dlia poshagovogo upravleniia luchevoi terapiei zlokachestvennykh opukholei.

The problem of step-by-step control of radiotherapy of malignant tumors was solved on the basis of Ellis' concept, widely used in radiology. A new method for determining step parameters was proposed. An algorithm and an example of the calculation of parameters of a course of therapy in case of a heterogeneous tumor were given.

[3 years' experience of radiation therapy with fast neutrons on the V-120 cyclotron]. / Trekhletnii opyt luchevoi terapii bystrymi netronami na tsiklotrone V-120.

The paper discusses the results of treatment of 128 patients with head and neck cancer in whom fast neutrons (Y-120; approximately 6.2 MeV) were used as a single procedure or in combination with surgery. Tumors of different histomorphologic structure displayed unequal sensitivity to fast neutrons. Mean disease-free survival in patients with complete regression of tumor was 24 months following neutron therapy alone, 18.5 months after combined neutron-photon treatment and 5.5 months only in controls. Relapse rates were 20 and 15% in patients with pre- and postoperative neutron treatment, respectively, as compared to 52% in controls.

[The TDF model of the teletherapy of malignant tumors using fast neutrons]. / Model' VDF dlia distatsionnoi terapii zlokachestvennykh opukholei bystrymi neitronami.

The paper describes a method of mathematical expressions of a TDF model in application to gamma-beam therapy of malignant tumors with fast neutrons. The maximum TDF value and an irradiated field area showed correlation; a bias for the enlargement of a single focal dose and neutron energy was introduced.

[Dependence of the therapeutic benefit factor on the dose of fast neutrons]. / K issledovaniiu zavisimosti terapevticheskogo faktora vyigrysha ot dozy dlia bystrykh neitronov.

An analytical equation was obtained to describe the therapeutic effectiveness factor (TEF) as a function of radiation dose. By this equation TEF function of dose was found for rhabdomyosarcoma that showed a considerable dependence of TEF upon dose fractionation schedule. At the same time, TEF gave no unique information on the advantage of neutron therapy since doses at which TEF was maximum did not correspond to those providing the highest effectiveness of the treatment.

[Small-size betatron for electron therapy of surface tumors and its clinical evaluation]. / Malogabaritnyi betatron dlia élektronnoi terapii poverkhnostnykh opukholei i ego klinicheskaia aprobatsiia.

The paper is concerned with the physicotechnical characteristics of a small-size betatron (with the energy of 7 MeV) designed in the Tomsk Polytechnical Institute for therapy of patients with superficial malignant tumors. An electron beam with the energy of 7 MeV was produced on the small-size betatron, irradiation fields were formed, and absorbed dose distribution was studied. The efficacy of the use of the beam in 110 patients with superficial malignant tumors was analyzed. The use of electron beam radiation was found promising for therapy of patients with locally spread types of skin and lower lip cancers and breast cancer local recurrences. Complete tumor regression was noted in 75-90% of the patients. Intraoral cone electron therapy combined with 60Co-therapy of surgery was employed for early cancer of the oral cavity.

[Experience with neutron teletherapy of malignant tumors]. / Opyt distantsionnoi neitronnoi terapii zlokachestvennykh opukholei.

A medico-biological complex for fast neutron therapy of cancer and research in physics and radiobiology was developed at the Siberian Branch of the Center within the framework of Cyclotron Department of Research Institute of Nuclear Physics (Polytechnical Institute, Tomsk). Certain problems of forming a fast neutron beam from the Y-120 type cyclotron are discussed. Baseline data of dosimetric and radiobiologic studies are presented. The first experience of Soviet researchers with fast neutron treatment of head and neck cancer is described. Favorable preliminary results suggest further clinical application of the said procedure.

[Neutron therapy of head and neck tumors]. / Neitronnaia terapiia opukholei golovy i shei.

The results of therapy of 55 head and neck tumor patients using fast neutrons of the Y-120 cyclotron of the Research Institute of Nuclear Physics, Tomsk Polytechnical Institute, were analyzed. For design of courses of neutron and combined neutron-photon therapy formulas of DMF calculation were used in cases of homogeneous and arrhythmic dose fractionation. The authors presented some data on methods of therapy with fast neutrons, dose fractionation schedules, a focal dose value, and time of treatment. Complete tumor regression was noted in 50-54% of cases using fast neutrons alone or in combination with photon radiation. A high sensitivity to neutron radiation of nonepidermoid carcinomas as compared to epidermoid cancer types was established with relation to tumor morphological structure.