Brain function is widely investigated with functional magnetic resonance imaging (fMRI) in humans and animals. In fMRI, the time courses of voxels typically reflect the local blood-oxygen level, which is taken as an indicator of neuronal activity. Voxel timecourse correlations are often explicitly modeled and interpreted in terms of neuronal interactions. They also affect standard analyses that...

Introduction Accurate estimation of the absorbed dose in radiosensitive organs, located away from the target volume during radiotherapy, is one of the main reasons for the development of reference phantoms. The International Commission on Radiological Protection (ICRP) reference phantoms can provide a more realistic view of the human anatomy in comparison with the previously used mathematical p...

The specific absorbed fraction (SAF) of energy is an essential element of internal dose assessment. Here reported a set of SAFs calculated for selected organs of a human voxel-based phantom. The Monte Carlo transport code GATE version 6.1 was used to simulate monoenergetic photons and electrons with energies ranging from 10 keV to 2 MeV. The particles were emitted from three source organs: kidn...

We have segmented CT torso+head and MRI head slices of two living human males. The manually segmented 129 x-ray CT transverse slices were used to create a computerized 3dimensional volume array modeling all major internal structures of the body. The original xray CT images were reconstructed in a 512x512 matrix with a resolution of 1 millimeter in the x,y plane. The z-axis resolution is 1 centi...

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...

Introduction A few methods for brain tissue segmentation based on diffusion tensor imaging (DTI) data have been proposed. These methods are utilized for studying the diffusivity of gray matter (GM) or subcortical white matter (WM) in neurodegenerative and neurological diseases [1, 2]. Although the accuracy of the segmentation performance might have significant influence on the diffusivity measu...

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...

PURPOSE Develop a technique to fabricate a 3D anthropomorphic breast phantom with known ground truth for image quality assessment of 2D and 3D breast x-ray imaging systems. METHODS The phantom design is based on an existing computer model that can generate breast voxel phantoms of varying composition, size, and shape. The physical phantom is produced in two steps. First, the portion of the vo...

Introduction: Because of the importance of vertebral compressive fracture (VCF) role in increasing the patients’ death rate and reducing their quality of life, many studies have been conducted for a noninvasive prediction of vertebral compressive strength based on bone mineral density (BMD) determination and recently finite element analysis. In this study, QCT-voxel based nonlinear finite eleme...

PURPOSE Many radiomics features were originally developed for non-medical imaging applications and therefore original assumptions may need to be reexamined. In this study, we investigated the impact of slice thickness and pixel spacing (or pixel size) on radiomics features extracted from Computed Tomography (CT) phantom images acquired with different scanners as well as different acquisition an...