background: in radiation treatment of moving targets located in thorax region of patient body, the delivered dose does not match with the planned treatment, resulting in some over and under dosage in the tumor volume, as a function of motion magnitude and frequency. several efforts have been done to investigate the target motion effects on dose distribution in the target and surrounding normal ...

background: understanding of the incident electron energy and angular distributions from clinical electron accelerators (linacs) is important for dosimetry and treatment planning. the most important goals of this study were to evaluate the energy fluence and angular distributions of electron beams from a neptun 10pc linac using the monte carlo (mc) code. materials and methods: the linac electro...

We develop a practical forward fitting method based on the SIMPLEX algorithm with shaking, which allows the derivation of the magnetic field and other parameters along a solar flaring loop using microwave imaging spectroscopy of gyrosynchrotron emission. We illustrate the method using a model loop with spatially varying magnetic field, filled with uniform ambient density and an evenly distribut...

Introduction Range and diffusion of positron-emitting radiopharmaceuticals are important parameters for image resolution in positron emission tomography (PET). In this study, GEANT4 toolkit was applied to study positron diffusion in soft tissues with and without a magnetic field for six commonly used isotopes in PET imaging including 11C, 13N, 15O, 18F, 68Ga, and 82Rb. Materials and Methods GEA...

Light induced waveguides produced by lateral illumination of a hotorefractive crystal show a complex dynamic evolution upon removal of the sustaining applied electric field. Using this effect, deflection and modulation of the guided light is realized by taking advantage of the screening and counter-screening of the space charge distribution. The spot separation upon deflection can exceed 10 tim...

PURPOSE Hypofractionated partial breast irradiation (HPBI) involves treatment to the breast tumor using high doses per fraction. Recent advances in MRI-Linac solutions have potential in being applied to HPBI due to gains in the soft tissue contrast of MRI; however, there are potentially deleterious effects of the magnetic field on the dose distribution. The purpose of this work is to determine ...

BACKGROUND AND PURPOSE The use of 3.0-T MR systems is increasing worldwide. We evaluated magnetic field interactions and translational attraction for 32 aneurysm clips in association with exposure to "long-bore" and "short-bore" 3.0-T MR imaging systems. METHODS Thirty-two different aneurysm clips were evaluated in this investigation. Each aneurysm clip was qualitatively evaluated for magneti...

We present calculations on the magnetocapacitance of the twodimensional electron gas in a lateral semiconductor superlattice under two-dimensional weak periodic potential modulation in the presence of a perpendicular magnetic field. Adopting a Gaussian broadening of magnetic-field-dependent width in the density of states, we present explicit and simple expressions for the magnetocapacitance, va...

The present thesis is focused on the development and application of narrow scanned high energy photon beams for radiation therapy. The introduction of physically and biologically optimized intensity modulated radiation therapy (IMRT) requires a flexible and accurate dose delivery method to maximize the treatment outcome. Narrow scanned photon beams is a fast option for IMRT since it is not depe...