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 This study explores the possibility of a new method for x-ray computed tomography (CT) calibration by means cross-calibration with proton CT (pCT) data. The proposed aims at more accurate conversion Hounsfield Units (HU) into stopping power ratio (SPR) relative to water be used in proton-therapy treatment planning. Methods X-ray scan was acquired on synthetic anthropomorphic phantom, co...

In this paper, we present a novel implementation of a dose calculation application, based on the GEANT4 Monte Carlo toolkit. Validation studies were performed with an homogeneous water phantom and an Alderson-Rando anthropomorphic phantom both irradiated with high-energy photon beams produced by a clinical linear accelerator. As input, this tool requires computer tomography images for automatic...

Introduction: Dynamic and 4D MRI have been used to understand the functional and metabolic aspects of disease and its progression. Examples include dynamic contrast enhancement (DCE) for micro-vasculature of tumors and MR spectroscopic imaging (MRSI) for tissue bio-chemistry. The post-processing strategy for most of these protocols consists of obtaining parametric maps using voxel-by-voxel esti...

We introduce a new hybrid approach for spline-based elastic registration of multimodal medical images. The approach uses point landmarks as well as intensity information based on local analytic measures for mutual information. The intensity similarity metrics are computationally efficient and can be optimized independently for each voxel. We have successfully applied our approach to synthetic i...

Conventional interpolation algorithms for reconstructing freehand three-dimensional (3D) ultrasound data always contain speckle noises and artifacts. This paper describes a new algorithm for reconstructing regular voxel arrays with reduced speckles and preserved edges. To study speckle statistics properties including mean and variance in sequential B-mode images in 3D space, experiments were co...

introduction: gafchromic ebt films are one of the self-developing and modern films commercially available for dosimetric verification of treatment planning systems (tpss). their high spatial resolution, low energy dependence and near-tissue equivalence make them suitable for verification of dose distributions in radiation therapy. this study was designed to evaluate the dosimetric parameters of...

Purpose: In longitudinal oncological and brain PET/CT studies it is important to understand the repeatability of quantitative PET metrics in order to assess change in tracer uptake or binding. The present studies were performed in order to assess the aspects of PET/CT repeatability related to reconstruction settings, analysis methods, scan duration (or image noise) and position in the field of ...

Purpose: To develop and test an integrated simulation system based on the digital Extended Cardio Torso (XCAT) phantom for 4-dimensional (4D) radiation therapy of lung cancer. Methods: A computer program was developed to facilitate the characterization and implementation of the XCAT phantom for 4D radiation therapy applications. To verify that patient-specific motion trajectories are reproducib...