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This paper describes the design of a multi-frequency Electrical impedance tomography (EIT) system, which provides a flexible mechanism for addressing up to 48 electrodes for imaging conductivity and permittivity distributions. A waveform generator based on a digital signal processor is used to produce sinusoidal waveforms with the ability to select(More)
This paper presents a trust-region implementation for image reconstruction of conductivity changes in electrical impedance tomography. A dogleg trust-region algorithm is applied in different cases to detect abnormalities. The dogleg algorithm approximates a Levenberg-Marquardt step within the trust region of the model function with a quadratic model. The(More)
During the recommissioning of a Philips RT-250 kilovoltage X-ray unit, unexpected output variations with tube head rotation (cross-plane) and tube head tilt (in-plane) were observed. The measured output showed an increase of up to 7.3% relative to the neutral position (0? in-plane and 0? cross-plane) over the possible range of angles of in-plane rotation(More)
For the management of mobile tumors, respiratory gating is the ideal option, both during imaging and during therapy. The major advantage of respiratory gating during imaging is that it is possible to create a single artifact-free CT data-set during a selected phase of the patient's breathing cycle. The purpose of the present work is to present a simple(More)
Electrical impedance tomography, EIT, is an imaging modality in which the internal conductivity distribution of an object is reconstructed based on voltage measurements on the boundary. This reconstruction problem is a nonlinear and ill-posed inverse problem, which requires regularization to ensure a stable solution. Most popular regularization approaches(More)
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