In the International Atomic Energy Agency's (IAEA) code of practice (TRS 398) and the American Association of Physicists in Medicine's dosimetry protocol (TG-51), full-scatter water phantoms are recommended for the determination of the absorbed dose for both photon and electron beams and, consequently, for the calibration of the user's ionization chambers. This procedure is applied in the Secon...

Diffusion MRI (DMRI) comprises a growing list of methods, and with that the need for a reliable and robust MRI phantom with which one can calibrate and validate them. In this study we developed a novel anisotropic diffusion MRI phantom and demonstrated its applicability by producing fractional anisotropy (FA) maps derived from DTI and average pore diameter maps using double Pulsed Field Gradien...

BACKGROUND Recent studies in eye plaque brachytherapy have shown a considerable difference between the dosimetric results using water phantom and a model of human eye containing realistic materials. In spite of this fact, there is a lack of simulation studies based on such a model in proton therapy literatures. In the presented work, the effect of utilizing an eye model with ocular media on pro...

PURPOSE A chest phantom study was conducted to evaluate the image quality of newly developed high-speed rotation multiplied projection-single photon emission computed tomography (HSRMP-SPECT) images. MATERIALS AND METHODS HSRMP-SPECT images of a chest phantom consisting of a simulated lung structure filled with 5000 ml of water containing 185 MBq Tc-99m-pertechnetate, and several small 11 mm ...

Figure 2: Phantom images and separated fat-only and water-only images for (a) FTED, (b) nulling at RF, (c) nulling at the echo center. Flow-artifacts are effectively reduced in (b) and (c). Note that water tube in (a) and (b) was incorrectly separated into the fat-only image because the existing region growing algorithm cannot handle disconnected objects. (c) (b) (a) Flow Compensation in Freque...

PURPOSE The aim of this work is to evaluate the application of tissue-specific dose kernels instead of water dose kernels to improve the accuracy of patient-specific dosimetry by taking tissue heterogeneities into consideration. MATERIALS AND METHODS Tissue-specific dose point kernels (DPKs) and dose voxel kernels (DVKs) for yttrium-90 (90Y), lutetium-177 (177Lu), and phosphorus-32 (32P) are ...

conclusion we constructed and validated a ct colonography phantom with correct density allowing performance of reproducible experiments. materials and methods we found 15 different phantom designs by literature search and compared their advantages and disadvantages based on their description and images. we tested various materials for density and mechanical properties and constructed a phantom ...

Introduction: Three physical conditions caused an external beam designated as a small field. The first is the loss of lateral charged particle equilibrium. The second is the effect of collimators on the primary photon source occlusion. The third condition is the size of the detector which is large compared to the field size. The most obvious perturbation effects in last condit...

PURPOSE To demonstrate the feasibility of using chemical shift magnetic resonance (MR) imaging fat-water separation methods for quantitative estimation of transcatheter lipiodol delivery to liver tissues. MATERIALS AND METHODS Studies were performed in accordance with institutional Animal Care and Use Committee guidelines. Proton nuclear MR spectroscopy was first performed to identify lipiodo...

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...