Model based iterative reconstruction (MBIR) algorithms have recently been applied to computed tomography and demonstrated superior image quality. MBIR algorithms also have the potential to incorporate sophisticated models of data acquisition to address artifacts. In this paper, we introduce kinetic models to the MBIR framework, which allow voxel value to change as a function of time. Convention...

designed in [2] for unobstructed Glu and Gln detection with chosen (TE, TM) regions in white boxes for phantom experiments. Fig. 2. In vitro STEAM spectra of Glu and Gln acquired at (72ms, 06 ms) and (84 ms, 58 ms) at 3T and multiplied with a filter to render them representative of typical in vivo line widths. Fig. 3. In vivo STEAM spectra acquired from a voxel including the ACC of a healthy vo...

Annually, many people are irradiated for diagnostic and therapeutic purposes. Assessment of radiation dose and its related risks to patients are important issues in radiation protection dosimetry. The complex mathematical calculations of the absorbed and effective doses are now done with computers. The calculations are performed with the help of anthropomorphic computational models of human bod...

Female and male adult human phantoms, called FASH (Female Adult meSH) and MASH (Male Adult meSH), have been developed in the first part of this study using 3D animation software and anatomical atlases to replace the image-based FAX06 and the MAX06 voxel phantoms. 3D modelling methods allow for phantom development independent from medical images of patients, volunteers or cadavers. The second pa...

Brain activation studies based on PET or fMRI seek to explore neuroscience questions by statistically analyzing the acquired images to produce statistical parametric images (SPIs). An increasingly wide range of univariate and multivariate analysis techniques are used to generate SPIs in order to detect mean-signal activations and/or long-range spatial interactions. However, little is known abou...

PURPOSE To describe our approach to mapping the functional information provided by single photon emission computed tomography (SPECT) onto the anatomic template provided by MR, and to determine both the number of markers required to achieve accuracy and the impact of voxel shape on accuracy. METHODS Point-to-point iterative minimization using externally fixed fiducial markers was involved and...

A special acrylic phantom designed for both magnetic resonance imaging (MRI) and computed tomography (CT) was used to assess the geometric accuracy of MRI-based stereotactic localization with the Leksell stereotactic head frame and localizer system. The acrylic phantom was constructed in the shape of a cube, 164 mm in each dimension, with three perpendicular arrays of solid acrylic rods, 5 mm i...

Voxel-based analysis of diffusion MRI data is increasingly popular. However, most white matter voxels contain contributions from multiple fibre populations (often referred to as crossing fibres), and therefore voxel-averaged quantitative measures (e.g. fractional anisotropy) are not fibre-specific and have poor interpretability. Using higher-order diffusion models, parameters related to fibre d...

Purpose: GABA is a very important inhibitory neurotransmitter, which is present at a very low concentration in the brain (~1 mM). Special spectral editing is necessary at clinical field strengths in order to detect GABA by magnetic resonance spectroscopy. Jdifference spectroscopy is a very efficient way of spectral editing GABA signal and is widely used. It is a common practice to report [GABA]...

Our institution delivers TBI using a modified Theratron 780 60Co unit. Due to limitations of our treatment planning system in calculating dose for this treatment, we have developed a fast Monte Carlo code to calculate dose distributions within the patient. The algorithm is written in C and uses voxel density information from CT images to calculate dose in heterogeneous media. To test the algori...