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PURPOSE The accuracy of intensity-modulated radiotherapy (IMRT) delivery may be compromised by random spatial error and systematic anatomic changes during the treatment course. We present quantitative measurements of the spatial variability of head-and-neck organs-at-risk and demonstrate the resultant dosimetric effects. METHODS AND MATERIALS Fifteen(More)
In recent years, magnetic-resonance imaging of gelatin doped with the Fricke solution has been applied to the direct measurement of three-dimensional (3D) radiation dose distributions. However, the 3D dose distribution can also be imaged more economically and efficiently using the method of optical absorption computed tomography. This is accomplished by(More)
A GLC analysis is presented for loxapine, amoxapine, and their major metabolites in serum and urine. Electron-capture detection is employed for serum analysis, and flame ionization is used for urine analysis. The procedure includes trifluoroacetylation of secondary amine functions, followed by trimethylsilylation of phenolic groups after ethyl acetate(More)
A chromatographic method for quantifying the potential memory-enhancing agent CL 275,838 (I) in human plasma with a limit of detection of 1.25 ng/ml is described. The procedure relies on isolation of the compounds from plasma constituents using the Sep-pack C18 cartridge, resolution by reverse-phase high pressure liquid chromatography (HPLC) and post-column(More)
PURPOSE The purpose of this study is to investigate the improvement of megavoltage planar and cone-beam CT (CBCT) image quality with the use of low atomic number (Z) external targets in the linear accelerator. METHODS In this investigation, two experimental megavoltage imaging beams were generated by using either 3.5 or 7.0 MeV electrons incident on(More)
The corrosion of Ag in an atmosphere of ozone and humidity with or without irradiation by ultraviolet (UV) light was investigated. A modified coulometric reduction technique was used, substituting sulphate solution for chloride solution, to prevent the spontaneous transformation of silver oxide corrosion product to chloride in the reduction solution. The(More)
An automated adaptation of the Bratton-Marshall procedure for sulfonamides has been developed. As sulfonamidesexhibit varying degrees of protein binding, applicahon of the method to plasma is dependent upon release of these compoundsprior to automated dialysis. This release is effected by the acidification of the sample. The results obtained with and(More)
Corrosion of aluminum alloy structures costs the US Air Force in the order of US$1 x 10(9) annually. Corrosion develops in areas of overlap such as aircraft lap-splice joints and under protective organic coatings. Capillary electrophoresis (CE) has been used to determine the local chemistries at these corrosion sites of solutions that were extracted using a(More)
A computational code that was originally designed to model crevice corrosion was extended to multifunctional coatings on Al alloys exposed to thin layers of electrolytes. The model is able to calculate the transient distributions of potential, current density, and all chemical species concentration, enabling the dynamic simulation of inhibitor release,(More)