The purpose of this study was to evaluate the quality and accuracy of cone beam computed tomography (CBCT) gated by active breathing control (ABC), which may be useful for image guidance in the presence of respiration. Comparisons were made between conventional ABC-CBCT (stop and go), fast ABC-CBCT (a method to speed up the acquisition by slowing the gantry instead of stopping during free breat...

PURPOSE The goal of this work was to evaluate measured vs. calculated surface dose as a function of PTV-to-skin proximity and calculation matrix oxel size, determine effects on plan quality, and provide parameters and levels of uncertainty for clinical use. METHODS A right-sided CTV with the lateral border 5mm from the surface was delineated on the CT data of a head and neck phantom. A 5mm PT...

A patient's position changes in every CBCT scan despite patient alignment protocols. However, there have been studies to determine image quality differences when an object is located at the center of the field of view (FOV). To evaluate changes in the image quality of the CBCT scan according to different object positions, the image quality indexes of the Alphard 3030 (Alphard Roentgen Ind., Ltd...

In case of a radiological emergency situation involving accidental human exposure, a dosimetry evaluation must be established as soon as possible. In most cases, this evaluation is based on numerical representations and models of subjects. Unfortunately, personalised and realistic human representations are often unavailable for the exposed subjects. However, accuracy of treatment depends on the...

High angular resolution diffusion imaging (HARDI) has proven to better characterize complex intra-voxel structures compared to its predecessor diffusion tensor imaging (DTI). However, the benefits from the modest acquisition costs and significantly higher signal-to-noise ratios (SNRs) of DTI make it more attractive for use in clinical research. In this work we use contextual information derived...

High angular resolution diffusion imaging (HARDI) has proven to better characterize complex intra-voxel structures compared to its predecessor diffusion tensor imaging (DTI). However, the benefits from the modest acquisitions and significantly higher signal-to-noise ratios (SNRs) of DTI make it more attractive for use in clinical research. In this work we use contextual information derived from...

Double pulsed-field gradient (d-PFG) MRI can provide quantitative maps of microstructural quantities and features within porous media and tissues. We propose and describe a novel MRI phantom, consisting of wafers of highly ordered glass capillary arrays (GCA), and its use to validate and calibrate a d-PFG MRI method to measure and map the local pore diameter. Specifically, we employ d-PFG Spin-...

Recent MRS studies have indicated that a higher body mass index (BMI) is associated with lower brain metabolite levels. Generally, individuals with higher BMIs have more body fat deposits than individuals with normal BMIs. This single-voxel spectroscopy (SVS) study investigated possible effects of fat on MR-measured metabolite signal areas, which may at least partly explain the observed associa...

OBJECTIVE Phantoms with simulating mandibular trabecular bone structure fabricated using micro-stereolithography were applied for a quantitative evaluation of cone-beam computed tomography (CT) images. MATERIALS AND METHODS Phantoms with a three-dimensional lattice, in which a square pillar was set at 0.10, 0.20, 0.30 and 0.40 mm at the edge, spaced at 0.60 mm, were made of an acrylic resin u...

In vivo magnetic resonance spectroscopic imaging of the prostate using single-voxel and multivoxel two-dimensional (2D) J-resolved sequences is investigated at a main magnetic field strength of 3 T. Citrate, an important metabolite often used to aid the detection of prostate cancer in magnetic resonance spectroscopic exams, can be reliably detected along with the other metabolites using this me...