Search results for "beam [charged particle]"

Calibrating the Operational Beam Width and Maximum Range of a Ship Radar Used for Bird Observations

2010

In order to analyse quantitative radar observations of bird movements, one needs to know the dimensions of the air space surveyed by the radar. The present study shows how to calibrate the operational beam width and the maximum range of any radar for cross sections for different body sizes of songbirds. The trial used an X-band fan beam ship radar of 25 KW (Furuno Fr-2125) and a captive balloon. Metal spheres of different diameters, fastened to the bottom of the balloon at defined distances, corresponding to the radar cross sections of song birds, were moved in all three dimensions of the air space. Simultaneously to the location by radar, the position of the suspended sphere was measured b…

High-power laser-beam characteristics

2004

Applications of high-power lasers are very important, especially for cutting and welding. As it is known, laser-beam characteristics have not constant value in time. So we may have suitable testing methods which allow us to determine the principal beam characteristics. The testing methods have to be very accurate, very efficient and in the same time very short as duration. We must apply a 3-dimensional intensity analysis, to the photonic beam we are studying. The number of industrial applications of lasers is increasing. An important thing is to know the optical characteristics of the laser that we study. Only the complete knowledge of the laser parameters allows controlling the process. Fo…

Stiffness and strength of composite truss beam to R.C. column connection in MRFs

2015

Abstract The results of experimental and numerical investigations on the cyclic behavior of composite truss beam to reinforced concrete column connection of moment resisting frames are reported. The beams are constituted by a steel truss and end zone added rebar embedded within a concrete block cast in place, so that, after curing, the steel truss and the added rebar work together with the concrete matrix as reinforcement of the composite beam. Particularly, three specimens of two-span continuous beams were tested under monotonic and cyclic actions as three point bending test. With the goal to investigate about the behavior of the end zone of the beam integrated into a moment resisting fram…

Minor changes in the macrocyclic ligands but major consequences on the efficiency of gold nanoparticles designed for radiosensitization

2016

International audience; Many studies have been devoted to adapting the design of gold nanoparticles to efficiently exploit their promising capability to enhance the effects of radiotherapy. In particular, the addition of magnetic resonance imaging modality constitutes an attractive strategy for enhancing the selectivity of radiotherapy since it allows the determination of the most suited delay between the injection of nanoparticles and irradiation. This requires the functionalization of the gold core by an organic shell composed of thiolated gadolinium chelates. The risk of nephrogenic systemic fibrosis induced by the release of gadolinium ions should encourage the use of macrocyclic chelat…

Nasal anomalies review with CT or MRI: from congenital to malignant.

2014

Learning Objectives. To describe imaging findings of a wide spectrum of uncommon nasal cavity masses evaluated at our institution by CT, CBCT and MR imaging, clinically and pathologically proven. Background. In this work we present a succinct review of disease illustrated by a retrospective case series of nasalcavity masses, evaluated at our institution. between 2010 and 2013. Patients have been studied with different imaging modalities including multiraw computed tomography (CT), cone beam computed tomography (CBCT) and magnetic resonance imaging (MR) to illustrate the findings and to summarize the main diagnostic keypoints for the differential diagnosis of nasal masses. Clinicopathologica…

External-beam radiotherapy as preparative regimen for hepatocyte transplantation after partial hepatectomy

2006

Purpose: The transplantation of donor hepatocytes is considered a promising option to correct chronic liver failure through repopulation of the diseased organ. This study describes a novel selective external-beam irradiation technique as a preparative regimen for hepatocyte transplantation. Methods and Materials: Livers of dipeptidylpeptidase IV (DPPIV)–deficient rats were preconditioned with external-beam single-dose irradiation (25 Gy) delivered to two thirds of the liver. Four days later, a one-third partial hepatectomy (PH) was performed to resect the untreated liver section, and 15 million wild-type (DPPIV + ) hepatocytes were transplanted via the spleen into the recipient livers. The …

Prostate Metabolism After the Completion of Exclusive Radiation Is More Depleted After Seeds Brachytherapy Compared to External Beam Radiation Therap…

2012

International audience; Biochemical outcome after radiation therapy requires a protracted time. PSA decreases slowly over time so that it is difficult to differentiate immediately after the completion of radiation the impact of radiation in the prostate using brachytherapy or external radiotherapy. At 3 months, the mean PSA values were similar between the 2 groups: 2.54 ng/mL (±1.59) in the EBRT group and 1.88 ng/mL (±1.14) in the PPI group (p=0.23). For Choline levels, 3-months Choline / Baseline Choline ratios were 1.13 (±0.60) after EBRT vs. 0.45 (±0.23) in the PPI group (p=0.003). Similar results were observed for Citrate levels: 3-months Citrate level / Baseline Citrate level ratios we…

Fractionated External Beam Radiotherapy as a Suitable Preparative Regimen for Hepatocyte Transplantation After Partial Hepatectomy

2010

Purpose Hepatocyte transplantation is strongly considered to be a promising option to correct chronic liver failure through repopulation of the diseased organ. We already reported on extensive liver repopulation by hepatocytes transplanted into rats preconditioned with 25-Gy single dose selective external beam irradiation (IR). Herein, we tested lower radiation doses and fractionated protocols, which would be applicable in clinical use. Methods and Material Livers of dipeptidylpeptidase IV (DPPIV)-deficient rats were preconditioned with partial liver external beam single dose IR at 25 Gy, 8 Gy, or 5 Gy, or fractionated IR at 5 × 5 Gy or 5 × 2 Gy. Four days after completion of IR, a partial …

Changing trends in the national practice for external beam radiotherapy for children with central nervous system tumours in Spain: results from the c…

2003

SU-E-J-64: Evaluation of a Commercial EPID-Based in Vivo Dosimetric System in the Presence of Lung Tissue Heterogeneity

2014

Purpose: To study the performance of Dosimetry Check (DC), an EPID-based dosimetry software, which allows performing transit dosimetry, in low density medium, by comparing calculations in-phantom, and analysing results for 15 lung patients. Methods: DC software (v.3.8, pencil beam-based algorithm) has been tested, for plans (Eclipse v.10.0 TPS) delivered in two Varian Clinac iX equipped with aS1000 EPIDs.In the CIRS lung phantom, comparisons between DC and Eclipse (Acuros) were performed for several plans: (1) four field box; (2) square field delivered in arc mode; (3) RapidArc lung patient plan medially centred; (4) RapidArc lung patient plan centred in one lung. Reference points analysed:…