Introduction: For RF-spoiled gradient echo imaging (ie SPGR, FLASH, T1-FFE), the combination of spoiling gradients and quadratic phase cycling eliminates net transverse magnetization within a voxel [1-4] to enable pure T1 contrast. Generally, many RF excitations are required to attain steady state magnetization levels. Therefore, when unsaturated spins are flowing into the imaging volume, inflo...

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...

PURPOSE The Valencia HDR applicators are accessories of the microSelectron HDR afterloading system (Nucletron) shaped as truncated cones. The base of the cone is either 2 or 3 cm diameter. They are intended to treat skin lesions, being the typical prescription depth 3 mm. In patients with eyelid lesions, an internal shielding is very useful to reduce the dose to the ocular globe. The purpose of...

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 ...

The objective of calibrating TLD badges and radiation survey meters demand that accurate dose gets to the TLDs and radiation survey meters. A lead block mould and an ICRU slab phantom had been designed and constructed to collimate the panoramic Cs-137 source at the secondary standards dosimetry laboratory (SSDL) by experts at the National Nuclear Research Institute (NNRI) workshop of the Ghana ...

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...

Time-resolved transmittance spectroscopy was performed in the wavelength range of 610 or 700 to 1050 nm on phantom parallelepipeds and bone tissue cubes of different sizes. The data were best fitted with solutions of the diffusion equation for a laterally infinite slab and for a parallelepiped to investigate how size and optical properties of the samples affect the results obtained with the two...

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...