introduction in computed tomography (ct) technology, an optimal radiation dose can be achieved via changing radiation parameters such as ma, pitch factor, rotation time and tube voltage (kvp) for diagnostic images. materials and methods in this study, the brain, abdomen, and thorax scaning was performed using toshiba 16-slice scannerand standard aapm and ctdi phantoms. aapm phantom was used for...

introduction: secondary radiation such as photoelectrons, auger electrons and characteristic radiations cause a local boost in dose for a tumor when irradiated with an external x-ray beam after being loaded with elements capable of activating the tumor, e.g.; i and gd. materials and methods:  in this investigation, the mcnpx code was used for simulation and calculation of dose enhancement facto...

PURPOSE To introduce the concept of dose-mass-based inverse optimization for radiotherapy applications. MATERIALS AND METHODS Mathematical derivation of the dose-mass-based formalism is presented. This mathematical representation is compared to the most commonly used dose-volume-based formulation used in inverse optimization. A simple example on digitally created phantom is presented. The pha...

Use of computed tomography (CT) as a medical diagnostic imaging tool has increased in recent decades because of its technical advances in data acquisition speed and image reconstruction technology. The increased reliance on CT was accompanied by increased patient exposure to ionizing radiation, however, and concerns among radiologic professionals and the public regarding CT dose resulted in inc...

background: one of the means of assessing dose to patients from computed tomography (ct) procedure is through the determination of the skin entrance dose (esd) with the appreciation of the concern that ocular exposure effects from ct scan includes possible induction of cancer and cataract. due to the relatively more recent introduction of ct scans, little work has been done in this area in the ...

Introduction: Computed tomography (CT) consists of 11% of all imaging methods, but accounts for approximately 67% of radiation exposure due to diagnostic cases. More than one-third of all CT scans are done in the head and neck area. The thyroid gland is irradiated during CT head and neck. According to studies, this gland has the highest levels of radiation-induced cancer, and i...

PURPOSE To introduce the concept of energy minimization-based inverse optimization for external beam radiotherapy. MATERIALS AND METHODS Mathematical formulation of energy minimization-based inverse optimization is presented. This mathematical representation is compared to the most commonly used dose-volume based formulation used in inverse optimization. A simple example on digitally created ...