The problem of searching ways to enhance efficiency of cancer treatment is extremely important. One of the currently recognized methods of treatment is radiation therapy. However, efficiency of radiotherapy is limited by radiosensitivity of intact tissues surrounding the tumor on the one hand, and by radioresistance of the malignancy on the other hand. The problem of overcoming radiation resistance of tumors is a key element in the local control of tumor growth [1]. Introduction of radiosensitizers into a tumor with subsequent irradiation results in secondary radiation inside the tumor, thus increasing the effect of radiotherapy. Various substances capable of converting ionizing radiation can serve as radiosensitizers. This may be diagnostic preparations containing heavy chemical elements, such as iodine, gadolinium, gold nanoparticles, platinum and other chemicals [5]. The aim of our experiment was selection of a drug which would give a significant increase of the secondary radiation in biological tissues when irradiating with gamma rays (GR) with the energy of 1.25 MeV. We used as a radiation sensitizer a drug containing gold nanoparticles and iodine particles which, when introduced directly into a tumor, will increase energy of the radiation inside the tumor without increasing the dose permitted according to the plan of exposure.

Introduction. The article addresses background gamma radiation in residential premises of apartment buildings in Vladivostok. This study is based on earlier research undertakings focused on the sick building syndrome (SBS), which proves its high relevance. The research is focused on the intensity of background gamma radiation in the residential premises of apartment buildings in Vladivostok. New data obtained in the course of the field experiments, the scale of their analysis, the coverage of substantive issues concerning radiation intensity and its monitoring in residential buildings guarantee the novelty of this research project. These findings also have a practical value that deals with environmental safety. Materials and methods. Onsite examinations were conducted in the form of background gamma radiation measurements taken in versatile apartment buildings, built at different times and made of different materials. Results. This section contains analytical information about the lack of influence of the location of apartment buildings on background radiation inside the apartments examined within the framework of this research project. Measurement results represent a range of values depending on construction materials used. Principal regularities, derived from the measurement results, are based on the time of operation of residential buildings, which is of practical importance. Conclusions. Patterns of influence of building parameters on background radiation inside apartments allow to assess the condition of residential buildings. Background radiation information can be entered into BIM databases and used to formulate the approach to the design of buildings and urban infrastructure so that they were focused on their residents and users. Background radiation research findings, entered into the database and contributed to design algorithms which are customized to the needs of urban residents, will enable designers to project the overall quality of the living environment encompassing the built environment analyzed in this article and other nearby buildings and structures located in Vladivostok.

The effect of the tantalum, platinum and gold nanoparticles on the energy distribution of the high-energy photons in the tissue-equivalent media is studied. It was shown that the presence of nanoparticles results in emergence in the medium of the electron-positron pairs manifesting in the decrease in the number of the primary photons and emergence of the secondary photons with energies of 511 keV and lower.