نتایج جستجو برای: neutron
تعداد نتایج: 46140 فیلتر نتایج به سال:
Introduction BNCT is an effective method to destroy brain tumoral cells while sparing the healthy tissues. The recommended flux for epithermal neutrons is 109 n/cm2s, which has the most effectiveness on deep-seated tumors. In this paper, it is indicated that using D-T neutron source and optimizing of Beam Shaping Assembly (BSA) leads to treating brain tumors in a reasonable time where all IAEA ...
in this work, we had examined 7 different types of neutron sources -an isotropic point source, sending 14.1(mev) monoenergetic neutrons ,an spherical source with 30 micron radius sending 14.1 (mev) monoenergetic neutrons, and a 30 micron radius spherical source having gaussian fusion energy spectrum from a d-t fusion, with different bandwidths -1,10,50,100 and 1000 kev and investigated 5 differ...
due to importance of combination therapies in cancer treatment, this study was performed to find the effects of hyperthermia and neutron irradiation and heir combination on the human lymphocytes. blood samples were treated separately with 41.5 °c for 30 and 60 minutes, 43 °c for 15 and 30 minutes, as well as 10 cgy neutron irradiation. they also treated with hyperthermia followed by irradiation...
Background and purpose: High-energy photon beams above 8-10 MV used in external radiation therapy produce neutron in dealing with the linear accelerator components and other parts in radiation field. The weakening of neutrons due to the closing jaws collimator angle, in smaller field sizes can also be a contributing factor in changing the neutron spectrum. Since a direct measurement of the...
Background and Aim: One of the best radiotherapy methods that have been suggested for the treatment of cancers such as brain, head and neck, skin, and recently liver is boron neutron capture therapy. Therefore, neutron shielding in the treatment room is important because the absorption of neutrons in the shield may lead to the production of gamma rays, which can have destructive effects. While ...
background: high density concrete is extensively used for efficient radiation attenuation in radiotherapy rooms and nuclear reactors. over the past eight years, some efficient galena-based concrete samples for shielding x or gamma rays was produced. the goal of this study was to produce a novel high density concrete against neutron and photon radiations using tourmaline and galena. materials an...
background: the characteristics of secondary neutrons in a high energy radiation therapy room were studied using the mcnpx monte carlo (mc) code. materials and methods: two mc models including a model with full description of head components and a simplified model used in previous studies were implemented for mc simulations. results: results showed 4-53% difference between full and with the sim...
In last two decades the optimal neutron energy for the treatment of deep seated tumors in boron neutron capture therapy in view of neutron physics and chemical compounds of boron carrier has been under thorough study. Although neutron absorption cross section of boron is high (3836b), the treatment of deep seated tumors such as gliobelastoma multiform (GBM) requires beam of neutrons of higher ...
Due to importance of combination therapies in cancer treatment, this study was performed to find the effects of hyperthermia and neutron irradiation and heir combination on the human lymphocytes. Blood samples were treated separately with 41.5 °C for 30 and 60 minutes, 43 °C for 15 and 30 minutes, as well as 10 cGy neutron irradiation. They also treated with hyperthermia followed by irradiation...
The neutron collision cross-section is important in neutron use for a specific job, such as neutron therapy or even in nuclear reactors. In calculating computational codes such as MCNP, only information from the neutron-to-mass collision information contained in the computational code library is used, in the case of nanoscale particles in contrast to the mass of materials and / or particulate m...
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