Materials with high atomic numbers favor the occurrence of the photoelectric effect when they are irradiated with gamma rays. Therefore, the photoelectric effects of metal implants within the target regions in Gamma Knife Radiosurgery are worth studying. In the present work, Monte Carlo simulations using EGS4 were employed to investigate the resulting dose enhancements. A dose enhancement as hi...

BACKGROUND Arthropod-borne viral encephalitis of diverse origins shows similar clinical symptoms, histopathology and magnetic resonance imaging, indicating that the patho mechanisms may be similar. There is no specific therapy to date. However, vaccination remains the best prophylaxis against a selected few. Regardless of these shortcomings, there are an increasing number of case reports that s...

The usefulness of intravenous contrast-enhanced CT in delineating intraspinal cord tumors has not been well documented. To determine if intradural spinal tumors enhance, if the location and type of tumor can be determined, and if a double dose of contrast material provides more information than a single dose, a retrospective study of 23 patients with proven intradural extramedullary or intramed...

PURPOSE To determine the clinical utility of dual-energy computed tomography (CT) in evaluating solitary pulmonary nodules (SPNs). MATERIALS AND METHODS This study was approved by the institutional review board, and informed consent was obtained. CT scans were obtained before and 3 minutes after contrast material injection in 49 patients (26 men, 23 women; mean age, 60.39 years +/- 12.24 [sta...

background: the shielding methods in radiotherapy due to delivering an accurate radiation dose to cancer tissues and avoiding unnecessary dose to normal tissues are very important. these methods include lead standard blocks, individual molding and multi leaf collimator (mlc). the mlc method is not still common in iran radiotherapy centers. individual molding is better than the lead block shield...

Introduction: External radiotherapy is the most common method of radiotherapy which the most important problem associated with is that there is no difference between healthy and tumor tissues in dose absorption. One way to differentiate the dose sensitivity is to use metal-based nanoparticles. Bismuth oxide nanoparticles are good candidates for cancer radiotherapy. In this study, we investigate...

The functional activity of hippocampal neurons is strongly correlated with behavioral performance in a vertebrate model learning system, rabbit eyeblink conditioning. Using this system, we have previously shown that (a) complete removal of the hippocampus blocks acquisition of the conditioned response; (b) a calcium-dependent postsynaptic afterhyperpolarization is reduced in pyramidal cells rec...

background: natural background radiation of a particular region is one of the distinctive factors defining the status of environment. eloor island is an industrial area in ernakulum district of the state of kerala, india. the indoor and outdoor gamma level measurements have been carried out for the region for evaluating the annual effective dose to the population residing in this area. material...