The purpose of this work was to extend the verification of Monte Carlo based methods for estimating radiation dose in computed tomography (CT) exams beyond a single CT scanner to a multidetector CT (MDCT) scanner, and from cylindrical CTDI phantom measurements to both cylindrical and physical anthropomorphic phantoms. Both cylindrical and physical anthropomorphic phantoms were scanned on an MDC...

Introduction: Voxel based morphometry is a type of statistical parametric mapping that can be used to investigate the effect of diseases such as epilepsy, Alzheimer's disease and Parkinson's disease or other agent such as skills on brain structure (white matter, gray matter and cerebrospinal fluid). The aim of this study is evaluate the effectiveness of this method in detection of differen...

Introduction There is significant interest in evaluating the performance and reliability of white matter fiber tractography algorithms. Diffusion tensor imaging (DTI) approach [1] is a powerful tool for non-invasive investigation of microstructure and has been successfully applied to detect different white matter diseases [2]. DTI-based fiber tracking gives insights into the complex architectur...

INTRODUCTION In vivo P MRS is unique and can be used to assess the high energy phosphate (HEP) metabolites for studying the ATP metabolism and bioenergetics. However, its utility relies on the accuracy for quantifying the absolute metabolite concentrations, which has been a long-standing challenge in the in vivo MRS research field. Although different strategies have been applied for determining...

Quantitative description of cardiac motion is desirable to assist in detecting myocardial abnormalities from gated myocardial perfusion (GMP) emission computed tomography (ECT) images. While "optical flow" type of cardiac motion estimation (ME) techniques have been developed in the past, there has been no quantitative evaluation of their performance. Moreover, no investigation has been performe...

PURPOSE Partial volume effect in positron emission tomography (PET) can cause incorrect quantification of radiopharmaceutical uptake in functional imaging. A PET partial volume correction method is presented to attenuate partial volume blurring and to yield voxel-based corrected PET images. METHODS By modeling partial volume effect as a convolution of point spread function of the PET scanner,...

BACKGROUND CT perfusion images have a high contrast ratio between voxels representing different anatomy, such as tissue or vessels, which makes image segmentation of tissue and vascular regions relatively easy. However, grey and white matter tissue regions have relatively low values and can suffer from poor signal to noise ratios. While smoothing can improve the image quality of the tissue regi...

The Monte Carlo dose calculation method works by simulating individual energetic photons or electrons as they traverse a digital representation of the patient anatomy. However, Monte Carlo results fluctuate until a large number of particles are simulated. We propose wavelet threshold de-noising as a postprocessing step to accelerate convergence of Monte Carlo dose calculations. A sampled rough ...

BACKGROUND Metal implants, surgical clips and other foreign bodies may cause 'streaking' or 'star' artifacts in computed tomography (CT) reconstructions, for example in the vicinity of dental restorations or hip implants. The deteriorated image quality complicates contouring and has an adverse effect on quantitative planning in external beam therapy. METHODS The potential to reduce artifacts ...

background: the purpose of this study is to fabricate inexpensive in-house low cost homogeneous and heterogeneous human equivalent thorax phantom and assess the dose accuracy of the treatment planning systems (tps) calculated values for different lung treatment dosimetery. it is compared with thermoluminescent dosimeter (tld) measurement. materials and methods: homogeneous and heterogeneous tho...