نتایج جستجو برای: ct number linearity
تعداد نتایج: 1306030 فیلتر نتایج به سال:
background: the artificial neural networks (anns) are useful in solving nonlinear processes, without the need for mathematical models of the parameters. since the relationship between the ct numbers and material compositions is not linear, ann can be used for obtaining tissue density and composition. objective: the aim of this study is to utilize ann for determination of the composition and mas...
UNLABELLED The aim of this study was to evaluate differences in dopamine transporter SPECT images among different SPECT/CT devices and to determine the most appropriate region of interest (ROI) for semiquantitative evaluation. METHODS An anthropomorphic striatal phantom was filled with (123)I solutions of different striatum-to-background radioactivity ratios. Data were acquired using 2 SPECT/...
Recently a new iterative reconstruction algorithm named Iterative Reconstruction (SAFIRE) has been released by Siemens. This algorithm works in the raw data domain with noise reduction as main purpose, providing five different strengths. In this study, the effect of SAFIRE on image quality has been investigated using selected phantoms and a comparison with standard filtered back projection (FBP...
PURPOSE The imaging characteristics of two popular kV cone-beam CT (CBCT) and two MVCT systems utilised in image-guided radiation therapy (IGRT) were evaluated. MATERIALS AND METHODS The study was performed on Varian Clinac iX, Elekta Synergy S, Siemens Oncor, and Tomotherapy. A CT phantom (Catphan-504, Phantom Laboratory, Salem, NY) was scanned for measurements of image quality including ima...
This paper presents techniques to address static and dynamic errors in high performance continuous-time (CT), modulators. The inter-symbol interference (ISI)model is presented and existing ISI reduction techniques are reviewed. A novel technique has been presented which can high-pass shape both static mismatch and ISI error of each element of a multi-bit DAC while decorrelating the instantaneou...
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