Introduction Signal intensity uniformity in a magnetic resonance (MR) image indicates how well the MR imaging (MRI) system represents an object. One of the major sources of image non-uniformity in high-field MRI scanners is inhomogeneity of radio-frequency coil. The aim of this study was to investigate non-uniformity in head, head and neck, and body coils and compare the obtained results to det...

Objectives The aim of this in vitro study was to evaluate how a deviation from the horizontal plane, affects the image quality in two different CBCT-devices. Methods A phantom head SK150 (RANDO, The Phantom Laboratory, Salem, NY, USA) was examined in two CBCT-units: Accuitomo 80 and Veraviewepocs 3D R100 (J. Morita Mfg. Corp. Kyoto, Japan). The phantom head was placed with the hard palate par...

The equivalent dose rate per positron fluence for the human eye lens is calculated using a Monte Carlo simulation code, EGS5, with two mathematical models (a computational head voxel phantom and a simple eye model). The eye lens doses for medical staff and carers as received from a radiopharmaceutical such as F-FDG, which is used in PET examinations, when spilled on the floor, and from positron...

This study discusses the development of a computer-generated phantom to compare the effects of image realignment programs on functional MRI (fMRI) pixel activation. The phantom is a whole-head MRI volume with added random noise, activation, and motion. It allows simulation of realistic head motions with controlled areas of activation. Without motion, the phantom shows the effects of realignment...

Introduction: The advantage of high field MRI is high SNR which can increase image resolution or decrease acquisition time. However, there are some challenges, such as the RF wavelength effect and the power deposition in tissues. A comparison of three different volume coils loaded with the same spherical homogeneous phantom has been reported [1]. In order to mimic the B1 field distribution and ...

A new anthropometric phantom having the shape of the adult human knee and containing a removable femur, patella, tibia, and fibula, has been developed for use in calibrating in vivo measurements of bone-seeking radionuclides. The shell of the phantom is assembled in three interlocking sections so that the skeletal components can easily be exchanged. All the materials used in the phantom have th...

Purpose. – The aim of the present study was to quantitatively assess the performance of a block matching-based automatic registration algorithm integrated within the commercial treatment planning system designated ISOgrayTM from Dosisoft. The accuracy of the process was evaluated by a phantom study on computed tomography (CT), magnetic resonance (MR) and positron emission tomography (PET) image...

Introduction: In recent years, the use of magnetic resonance (MR) images in radiation treatment planning has drawn considerable attention. However, although the extent of a tumor can be determined in great detail on MR images, the geometric accuracy of these images is limited by distortions stemming from the inhomogeneity of the static background magnetic field, the nonlineari...

AIM To evaluate the effectiveness of haptic virtual reality (VR) simulator training using microcomputed tomography (micro-CT) tooth models on minimizing procedural errors in endodontic access preparation. METHODOLOGY Fourth year dental students underwent a pre-training assessment of access cavity preparation on an extracted maxillary molar tooth mounted on a phantom head. Students were then r...

background: polymer gel dosimetry is still the only dosimetry method for direct measuring of threedimensional dose distributions. mri polymer gel dosimeters are tissue equivalent and can act as a phantom material. in this study the obtained isodose maps with pagat polymer gel dosimeter were compared to those calculated with egsnrs for singleshot irradiations of 8 and 18 mm collimators of gamma ...