نتایج جستجو برای: neck phantom
تعداد نتایج: 103711 فیلتر نتایج به سال:
Background and purpose: Dose calculations in trachea HDR brachytherapy treatment planning systems are greatly based on TG-43 protocol in which, all materials including air inside trachea are treated the same as water. The aim of this study was to survey the effect of air on dose calculations of Flexiplan treatment planning system in trachea HDR brachytherapy. Materials and methods: To ev...
In this study, the MCNPX code version 2.6 has been used to simulate a proton therapy in thyroid gland. The neck phantom is cylindrical including skin, adipose, skeletal muscle and thyroid gland. Radiation source is close to the skin surface and single energy protons are collided perpendicular to the skin surface. The results of the simulation shows that the best proton energy interval, to cover...
Radiotherapy treatment planning integrating positron emission tomography (PET) and computerized tomography (CT) is rapidly gaining acceptance in the clinical setting. Although hybrid systems are available, often the planning CT is acquired on a dedicated system separate from the PET scanner. A limiting factor to using PET data becomes the accuracy of the CT/PET registration. In this work, we us...
This paper proposes an unsupervised tumour segmentation approach for PET data. The method computes the volumes of interest (VOIs) with sub-voxel precision by considering the limited image resolution and partial volume effects. First, an improved anisotropic diffusion filter is used to remove image noise. A hierarchical local and global intensity active surface modelling scheme is then applied t...
introduction: poor sensitivity and poor signal to noise ratio because of low injected thallium dose and presence of scattered photons are the main problems in using thallium in scintigraphic imaging of the heart. scattered photons are the main cause of degrading the contrast and resolution in spect imaging that result in error in quantification. thallium decay is very complicated and photons ar...
Optical pump-probe setups are commonly used for excitation and investigation of the spin dynamics in various types magnetic materials. Usually spatially homogeneous is considered, but here authors describe optical $n\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}u\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}f\phantom{\rule{0}{0ex}}o\phantom{\rul...
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