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INVESTIGATION OF EXPOSURE OF EPITHERMAL NEUTRONS RADIATION ON THE SAMPLES OF TUMOR TISSUES AT Gd-NCT
Kulabdullaev G.A.1, Kim A.A.1, Abdullaeva G.A.1, Djuraeva G.T.1, Yuldashev D.O.1, Mavlyanov I.R.2, Kadyrbekov R.T.3, Kadyrbekov N.R.3, Beknazarov H.J.3
1 Institute of Nuclear Physics, Academy of Sciences of Uzbekistan,
2 Tashkent Medical Academy, Ministry of Health, Uzbekistan
3 Republican Scientific Center of Neurosurgery, Ministry of Health, Uzbekistan
The purpose of the study was to assess the impact of radiation exposure of epithermal neutron and epithermal neutrons with gadolinium neutron capture reaction on the samples of brain tumor tissues.
For the experiments were carried out calculations for neutron capture reaction of gadolinium. Natural gadolinium is composed of seven isotopes, of which 155Gd and 157Gd have very large (n,) cross-section, are respectively 255,000 and 60,000 barns Therefore, these isotopes, which are> 30% natGd, are the most effective isotope for neutron capture. For natGd thermal neutron capture cross section is equal to 49,000 barns, whereby natGd is one of the widely used elements in neutron capture therapy.
To create the required absorbed dose in tumor tissue sample the different concentrations of gadolinium are used, which can be adjusted by diluting the starting preparation of Magnevist. The concentration of gadolinium in Magnevist is 65.916 mg/g (65.916 ppm).
In the reaction of epithermal neutron beam with biological tissue elements the release of energy takes place as a result of nuclear reactions and absorption of the secondary gamma-ray quanta. The nuclear reactions produce the charged particles and recoil nuclei having a short run, and their energy is absorbed in the layers with several tens of microns thick. Secondary gamma rays quanta have energies up to ~ 10 MeV, and their run is a few tens of centimeters. Therefore, calculation the dose in biological tissue requires knowledge of the full spectrum of gamma rays and the partial kerma dependence on neutron energy and the gamma rays quanta for all elements of the biological tissue. Kerma, a close analogue of the absorbed dose, at known neutron spectrum was determined by the method published earlier [1]. The database EPAPS [2] was used for calculation for partial neutron kerma depending on energy of elements, composing of biological tissue.
Investigations were carried out on the samples of human glioma tumor tissues extracted during standard surgical operation. From tumor tissue samples the living slices were prepared and placed in culture medium. Prepared living slices were used for epithermal neutron beam irradiation with different absorbed doses in the presence of gadolinium-containing preparation Magnevist (gadopentetata dimeglyumin) or without it. After irradiation, the slices of samples were incubated saline with 5% glucose for 24 hours at 4C. After incubation, slices were fixed in 10% formalin and histological analysis was performed for estimation of degree of tumor tissue necrosis. The findings allow to obtain accurate estimate the degree of necrosis of the tumor tissue after irradiation with different absorbed dose and at irradiation by epithermal neutrons and irradiation by epithermal neutrons with particles produced during the gadolinium-neutron capture reaction.
- G.A. Abdullayev, Yu.N. Koblik, G.A. Kulabdullaev, A.A. Kim, D. Juraev, A.F. Heavenly, Sh. Saytdzhanov. "Determination kerma biological tissue when irradiated with gadolinium epithermal neutron beam CM WWR RUz", J. Nuclear Energy, 2013, t.115, №3,166-169.
- EPAPS (Electronic Physics Auxillary Publication Service) (http://ftp.aip.org./epaps/medical_phys/E-MPHYA6-29-009201/)
