background: in this study, a method for linear attenuation coefficient calculation was introduced. methods: linear attenuation coefficient was calculated with a new method that base on the physics of interaction of photon with matter, mathematical calculation and x-ray spectrum consideration. the calculation was done for cerrobend as a common radiotherapy modifier and mercury. results: the valu...

normal 0 false false false en-us x-none ar-sa aim: ct number (hu) and linear attenuation coefficient contain useful information which  can be determined during usual ct scanning for the prediction of breast cancerous cells existence based on hemoglobin concentration. methods: this study used breast phantom containing major and minor vessels with diameters of 10 and 5 mm, respectively. the major...

introduction: the photoelectric attenuation coefficient of substances is known to depend upon the energy e of the photon and the effective atomic number of substances (zeff) as (zeff x /e y ).  no definitive values about these indices x, y are given in the literature. the index x is said to lie between, 3.0 and 4.0, while for ‘y’ different values have been assigned, between 3.0 and 4.0. methodo...

background: radiation shielding properties is an important for a material wish can be used the photon attenuation coefficients of clay produced using different rate of boron have been measured for the purpose of radioactive waste disposal. materials and methods: the measurement has been performed using gamma spectrometer contains nai (tl) detector at the photon energies of 662, 1173 and 1332 ke...

Background: In this study, a method for linear attenuation coefficient calculation was introduced.Methods: Linear attenuation coefficient was calculated with a new method that base on the physics of interaction of photon with matter, mathematical calculation and x-ray spectrum consideration. The calculation was done for Cerrobend as a common radiotherapy modifier and Mercury.Results: The values...

We review theoretical models to show that contrast reduction at a specific wavelength in the horizontal direction depends directly on the beam attenuation coefficient at that wavelength. If a black target is used, the inherent contrast is always negative unity, so that the visibility of a black target in the horizontal direction depends on a single parameter only. That is not the case for any o...

introduction:  the use of radioactive iodine (131i) has become an important adjunct to the treatment of thyroid cancer and hyperthyroidism. salivary gland has the ability to concentrate radioactive iodine under normal circumstances. salivary gland dysfunction and dry mouth are the common side effectsof high-dose radioiodine therapy. the purposeof this study was to determine the absorbed dose of...

in this paper the propagation of harmonic plane waves in a homogeneous anisotropic magneto-piezothermoelastic diffusive body with fractional order derivative is studied. the governing equations for a homogeneous transversely isotropic body in the context of the theory of thermoelasticity with diffusion given by sherief et al. [1] are considered as a special case. it is found that three types of...

objective: in this study, we aimed to validate the accuracy of computed tomography-based attenuation correction (ctac) using the bilinear scaling method.methods: the measured attenuation coefficient (μm) was compared to a theoretical attenuation coefficient (μt ) using four different ct scanners and an rmi 467 phantom. the effective energy of the ct beam x-rays was calculated, using the aluminu...