Background and purpose. The purpose of this investigation was to evaluate feasibility, safety and efficacy of radiotherapy for inoperable non-small-cell lung cancer (NSCLC). Various radiotherapy planning methods have been proposed to decrease normal tissue toxicity. We compared 2D-RT with 3D-RT for NSCLC. Parameters assessed included dose to PTV and organ-at-risk (OAR), multiple conformity and homogeneity indices. Material and methods. Initial and re-simulation CT images from 52 consecutive patients with IIB – IIIB NSCLC were used to quantify dosimetric differences between 2D and 3D conformal radiotherapy. Contouring was performed on both CTs, and plans (n=104 plans) and dose-volume histograms were generated. Results. All plans provided comparable PTV coverage. Compared with 2D-RT, 3D-RT significantly reduced the maximum dose to heart (p<0.01), spinal cord (p<0.01), whole lung (p<0.01), esophagus (p<0.02) – Wilcoxon test.

The paper presents results of analysis of thyroid cancer incidence among males participated in clean-up work within the 30-km Chernobyl exclusion zone from the 26 th April through the 31 st December 1986. The considered follow up period of the cohort made up of 27749 emergency workers (EWs), residents of six regions of the European part of Russia, is 1992-2010. The analysis was based on data of the National Radiation Epidemiology Registry (NRER). All cohort members have documented radiation dose from external exposure. The cohort consisted of two groups of the accident workers, the group 1 consists of 5650 so called “exposed” EWs worked from April 26 to May 31 and exposed both to external radiation and 131I; the group 2 of so called “unexposed” EWs consists of 22099 males worked within the zone from June through December 1986, and exposed to external radiation only. For the whole period of follow-up 49 thyroid cancer cases were registered. For estimating risk of thyroid cancer associated with exposure to 131I and exact confidential limits the data of “exposed” vs. “unexposed” contingency tables were used. For calculating risk of thyroid cancer associated with external exposure only (the group 2) the maximum likelihood estimation for relative risk linear model was used. The odds ratio is 1.4 (0.71, 2.70 90% CI). Excess relative risk per 1 Gy in the group 2 (“unexposed”) is 1.87 (-2.16, 26.38 90% CI). The calculated mean radiation dose to the thyroid from 131I is 0.22 (0.05, 0.70 90% CI) Gy. According to obtained estimates, contribution of 131I to radiation associated thyroid cancer among EWs worked in the 30-km Chernobyl exclusion zone in May 1986 is 53%.

Computed system ARMIR was developed with the support of the Administration of the Nuclear Weapons Complex. It allows evaluating radiation risks from occupational exposure in more than 85 % of the Corporation Rosatom staff working under individual dosimetry monitoring. Summary data on occupational risks are given in the paper. Characteristics of a group at high risk were defined. Majority of workers (88.6 % of males and 93.08 % of females) are at trivial occupational risk. The ARMIR system is based on mathematical models of radiation risk recommended by ICRP. The use of the models for evaluating radiation risks in Russian nuclear workers is justified.

The comparative evaluation of analgesic effect of palliative external beam, radionuclide (153Sm and 89Sr) and combined (external beam plus radionuclide 153Sm ) radiation therapy for 579 patients with bone metastases of breast carcinoma was carried out. High efficiency of combined radiation therapy was shown.

The paper discusses the results of analysis of radiation risks of thyroid cancers among the Chernobyl emergency workers (living in Russia) resulting from exposure to iodine radioisotopes. Due to the lack of documented doses from this source, the characteristics of the curve of this radionuclide decay were used for analysis. The analysis was performed by two independent methods: the exposed versus unexposed (the exposed are the emergency workers who worked in the 30-km zone during the first 65 days after the accident and the unexposed are those working there later) and the regression analysis based on the maximum likelihood method using the surrogate dose (period and time of stay in the 30-km zone during 131I decay). By both methods statistically significant estimates were derived for the relative radiation risk 1.8 (1.2; 2.8 95 % CI) and for the excess radiation risk per unit surrogate dose 2.5 (0.2; 6.5 95 % CI). The obtained results indicate that the follow-up of the emergency workers in relation to this issue should be continued.