We compare two different implementations of a 3D SPECT system model for iterative reconstruction, both of which compensate for non-uniform photon attenuation and depth-dependent system response. One implementation performs fast rotation of images represented using a basis of rectangular voxels, whereas the other represents images using a basis of rotationally symmetric volume elements. In our s...

MREPT: An overview •Magnetic Resonance Electrical Property Tomography (MREPT) aims to visualize both conductivity σ and permittivity ǫ distributions at the Larmor frequency (≈ 128 MHz for a 3 T MRI). • In MREPT, we feed an ac current at the Larmor frequency through a coil located outside of the imaging object Ω. In Ω, the injected current will induce a magnetic field H = (Hx Hy Hz). For r = (x,...

Image reconstruction using data-dependent triangulation" (2001). All Faculty Publications. Paper 571.

A novel reconstruction technique, called Wiener Filtered Reconstruction Technique (WIRT), for sparse-data tomographic imaging is introduced. This six-step method applies a spatially varying constrained leastsquares filter combined with a regularization method based on total variation. The WIRT reconstruction is implemented in the frequency domain, where the information based on measurements and...

Current computed tomography (CT) scanners, including micro-CT scanners, utilize a point x-ray source. As we target higher and higher spatial resolutions, the reduced x-ray focal spot size limits the temporal and contrast resolutions achievable. To overcome this limitation, in this paper we propose to use a line-shaped x-ray source so that many more photons can be generated, given a data acquisi...

Traditionally, balloon-based radiosonde soundings are used to study the spatial distribution of atmospheric water vapour. However, this approach cannot be frequently employed due to its high cost. In contrast, GPS tomography technique can obtain water vapour in a high temporal resolution. In the tomography technique, an iterative or non-iterative reconstruction algorithm is usually utilised to ...

We compared reconstruction algorithms [filtered back projection (FBP), maximum likelihood expectation maximization (MLEM), and the simultaneous iterative reconstruction technique (SIRT)] in terms of the radiation dose and image quality, for exploring the possibility of decreasing the radiation dose during digital breast tomosynthesis (DBT). The three algorithms were implemented using a DBT syst...

This study compared reconstruction algorithms [filtered back projection (FBP) and simultaneous iterative reconstruction technique (SIRT)] with respect to radiation doses and image quality and suggested the possibility of decreasing the exposure dose in digital breast tomosynthesis (DBT). These two existing algorithms were implemented using a DBT system and experimentally evaluated using contras...

Parallel MRI techniques utilize the inherent encoding effect of receiver coil sensitivity for complementing gradient-driven Fourier encoding. As a consequence of this hybrid encoding approach, parallel techniques require advanced reconstruction algorithms beyond mere Fourier transform. Generally, taking coil sensitivity into account renders the reconstruction problem more complex and numericall...