No abstract

The Dzhelepov Laboratory of Nuclear Problems' activity is aimed at developing three directions in radiation medicine: 3D conformal proton therapy, accelerator techniques for proton and carbon treatment of tumors, and new types of detector systems for spectrometric computed tomography (CT) and positron emission tomography (PET). JINR and IBA have developed and constructed the medical proton cyclotron C235-V3. At present, all basic cyclotron systems have been built. We plan to assemble this cyclotron at JINR in 2011 and perform tests with the extracted proton beam in 2012. A superconducting isochronous cyclotron C400 has been designed by the IBAÄJINR collaboration. This cyclotron will be used for radiotherapy with proton, helium and carbon ions. The 12 C 6+ and 4 He 2+ ions will be accelerated to an energy of 400 MeV/amu, the protons will be extracted at the energy 265 MeV. The construction of the C400 cyclotron was started in 2010 within the framework of the Archarde project (France). Development of spectrometric CT tomographs may allow one to determine the chemical composition of a substance together with the density, measured using traditional CT. This may advance modern diagnostic methods signiˇcantly. JINR develops fundamentally new pixel detector systems for spectrometric CT. The time-of-ight (TOF) system installed in the positron emission tomograph (PET) permits essential reduction in the detector noise from occasional events of different positron annihilations. The micropixel avalanche photodiodes (MAPDs) developed at JINR allow a factor of 1.5 reduction in the resolution time for the PET TOF system and suppression of the noise level as compared to commercial PET. The development of a combined PET/MRI is of considerable medical interest, but it cannot be made with the existing PET tomographs based on detectors of compact photomultipliers due to strong alternating magneticˇeld of MRI. Changeover to detectors of micropixel avalanche photodiodes permits making a combined PET/MRI. ‚ ‹ ¡μ• É앨¨Ö¤¥•´ÒÌ ¶•μ¡²¥³¨³. ‚.. "¦¥²¥ ¶μ¢ ˆŸˆ¢¥¤ÊÉ¸Ö ¶•¨±² ¤´Ò¥¨¸¸²¥¤μ¢-¨Ö ¢ μ¡² ¸É¨• ¤¨ Í¨μ´´μ°³¥¤¨Í¨´Ò, ¢±²ÕÎ ÕШ¥ ¢¸¥¡Ö 3-³¥•´ÊÕ ±μ´Ëμ•³´ÊÕ ¶•μÉμ´´ÊÕ É¥• ¶¨Õ, • §• ¡μÉ±Ê Ê¸±μ•¨É¥²Ó´μ°É¥Ì´¨±¨¤²Ö ¶•μÉμ´´μ°¨Ê£²¥•μ¤´μ°É¥• ¶¨¨, • §¢¨É¨¥´μ¢ÒÌ É¨ ¶μ¢ ¤¥É¥±Éμ•´Ò̸¨¸É¥³ ¤²Ö¸ ¶¥±É•μ³¥É•¨Î¥¸±μ£μ ±μ³ ¶ÓÕÉ¥•´μ£μ Éμ³μ£• Ë (Š')¨ ¶μ §¨É•μ´´μ-Ô³¨¸¸¨μ´´μ£μ Éμ³μ£• Ë (').

No abstract

No abstract

Purpose: To study was to study the effect of GNP nanoparticles on tumor cells of human lung carcinoma A 549 when irradiated with protons. Materials and methods: Cell culture: Human lung carcinoma cells A 549. Gold nanoparticles Au/PEG 6000/W 200/30 nm: A colloidal solution of gold nanoparticles purchased from the firm M 9 Nanomaterials & Technologies was used in the work. Proton irradiation: The irradiation of cells was carried out on a therapeutic proton beam in the Medical and Technical Complex of the Laboratory of Nuclear Problems Joint Institute for Nuclear Research. Determination of radiosensitivity of cells: By determining the clonogenic survival of cells. Determination of the genotoxic activity of nanoparticles under the action of proton irradiation: investigated using a micronucleus test with blocking cytokinesis. The genotoxicity of gold nanoparticles was estimated by the number of micronuclei per 1000 binuclear cells. Micronucleus were counted only in binuclear cells. At least 1000 binuclear cells were calculated for each dose, experiments were carried out in three repeats. Results: The frequency of micronucleus formation indicates an increase in the genotoxic effect of nanoparticles when irradiated with protons at a dose of 2 Gy. Proton irradiation caused an increase in the frequency of micronucleus formation depending on the concentration of nanoparticles. When irradiated with protons at a dose of 2 Gy in the presence and absence of nanoparticles, the difference in the frequency of micronucleus formation for the concentration of nanoparticles was 2.5 mg/ml – 1.1; for 5 mg/ml and 10 mg/ml – 1.2; for 15 mg/ml – 1.3 and for 30 mg/ml –1.5. Cell survival curves reflect a decrease in their survival rate when metal nanoparticles with high Z are added, which reflects the occurrence of radiosensitization effects. The gain for 10 % and 50 % survival rates is 1.4 and 2.5, respectively. Conclusions: Under the influence of proton irradiation, the genotoxic activity of gold nanoparticles in human lung carcinoma cells A 549 increases, depending on their concentration. The survival rate of human lung carcinoma A 549 cells irradiated with protons in the presence of gold nanoparticles decreases.