Effects of X-Rays, Electron Beam, and Gamma Irradiation on Chemical and Physical Properties of EVA Multilayer Films.

Gamma-ray irradiation, using the cobalt-60 isotope, is the most common radiation modality used for medical device and biopharmaceutical products sterilization. Although X-ray and electron-beam (e-beam) sterilization technologies are mature and have been in use for decades, impediments remain to switching to these sterilization modalities because of lack of data on the resulting radiation effects for the associated polymers, as well as a lack of education for manufacturers and regulators on the viability of these sterilization alternatives. For this study, the compatibility of ethylene vinyl acetate (EVA) multilayer films with different ionizing radiation sterilization (X-ray, e-beam, and gamma irradiation) is determined by measuring chemical and physical film properties using high performance liquid chromatography, differential scanning calorimetry, Fourier-Transform InfraRed spectroscopy (FTIR), surface energy measurement, and electron spin resonance techniques.

Integrated atomic force microscopy and x-ray irradiation for in situ characterization of radiation-induced processes.

Understanding radiation-induced chemical and physical transformations at material interfaces is important across diverse fields, but experimental approaches are often limited to either ex situ observations or in situ electron microscopy or synchrotron-based methods, in which cases the radiation type and dose are inextricably tied to the imaging basis itself. In this work, we overcome this limitation by demonstrating integration of an x-ray source with an atomic force microscope to directly monitor radiolytically driven interfacial chemistry at the nanoscale. We illustrate the value of in situ observations by examining effects of radiolysis on material adhesion forces in aqueous solution as well as examining the production of alkali nitrates at the interface between an alkali halide crystal surface and air.

Direct visualization of radiation-induced transformations at alkali halide-air interfaces.

Radiation driven reactions at mineral/air interfaces are important to the chemistry of the atmosphere, but experimental constraints (e.g. simultaneous irradiation, in situ observation, and environmental control) leave process understanding incomplete.

Deciding between an X-Ray and 137Cs Irradiator - It's not just about Energy Spectra.

Irradiators utilizing radioactive cesium-137 (Cs) or cobalt-60 (Co) gamma-ray sources have been used for biological applications for many decades. These applications include irradiation of much of the nation's blood supply and radiation biology research. In 2005, the U.

Beyond Californium-A Neutron Generator Alternative for Dosimetry and Instrument Calibration in the U.S.

Evaluations of neutron survey instruments, area monitors, and personal dosimeters rely on reference neutron radiations, which have evolved from the heavy reliance on (α,n) sources to a shared reliance on (α,n) and the spontaneous fission neutrons of californium-252 (Cf). Capable of producing high dose equivalent rates from an almost point source geometry, the characteristics of Cf are generally more favorable when compared to the use of (α,n) and (γ,n) sources or reactor-produced reference neutron radiations. Californium-252 is typically used in two standardized configurations: unmoderated, to yield a fission energy spectrum; or with the capsule placed within a heavy-water moderating sphere to produce a softened spectrum that is generally considered more appropriate for evaluating devices used in nuclear power plant work environments.

Detecting radiation-induced injury using rapid 3D variogram analysis of CT images of rat lungs.

Rationale And Objectives: To investigate the ability of variogram analysis of octree-decomposed computed tomography (CT) images and volume change maps to detect radiation-induced damage in rat lungs.

Materials And Methods: The lungs of female Sprague-Dawley rats were exposed to one of five absorbed doses (0, 6, 9, 12, or 15 Gy) of gamma radiation from a Co-60 source. At 6 months postexposure, pulmonary function tests were performed and four-dimensional (4D) CT images were acquired using a respiratory-gated microCT scanner.

A Dose-Dependent Hematological Evaluation of Whole-Body Gamma-Irradiation in the Göttingen Minipig.

There is a great deal of interest in the establishment of a standardized animal model for the acute radiation syndrome to allow development of diagnostic approaches and countermeasure treatments following radiological terrorist events. Due to physiological, anatomical, and biochemical similarities to humans, the minipig is an attractive large animal model for evaluating countermeasure efficacy. This study was conducted in order to aid in the establishment of the minipig, and the Göttingen minipig in particular, as an animal model for the hematopoietic acute radiation syndrome.

The Importance of Dosimetry Standardization in Radiobiology.

Radiation dose is central to much of radiobiological research. Precision and accuracy of dose measurements and reporting of the measurement details should be sufficient to allow the work to be interpreted and repeated and to allow valid comparisons to be made, both in the same laboratory and by other laboratories. Despite this, a careful reading of published manuscripts suggests that measurement and reporting of radiation dosimetry and setup for radiobiology research is frequently inadequate, thus undermining the reliability and reproducibility of the findings.

In vivo delivery of FTY720 prevents radiation-induced ovarian failure and infertility in adult female nonhuman primates.

Objective: To determine whether sphingosine-1-phosphate (S1P), or the S1P mimetic FTY720 shields ovaries of adult female rhesus monkeys from damage caused by 15 Gy of targeted radiotherapy, allowing for the retention of long-term fertility, and to evaluate whether S1P protects human ovarian tissue (xenografted into mice) from radiation-induced damage.

Design: Research animal study.

Setting: Research laboratory and teaching hospital.

Application of high-resolution 1H MAS NMR spectroscopy to the analysis of intact bones from mice exposed to gamma radiation.

Herein we demonstrate that high-resolution magic angle spinning (MAS) 1H NMR can be used to profile the pathology of bone marrow rapidly and with minimal sample preparation. The spectral resolution obtained allows several metabolites to be analyzed quantitatively. The level of NMR-detectable metabolites in the epiphysis + metaphysis sections of mouse femur were significantly higher than that observed in the diaphysis of the same femur.

Technical performance of the Luxel Al(2)O(3):C optically stimulated luminescence dosemeter element at radiation oncology and nuclear accident dose levels.

The dose ranges typical for radiation oncology and nuclear accident dosimetry are on the order of 2-70 Gy and 0.1-5 Gy, respectively. In terms of solid-state passive dosimetry, thermoluminescent (TL) materials historically have been used extensively for these two applications, with silver-halide, leuco-dye and BaFBr:Eu-based films being used on a more limited basis than TL for radiation oncology.

A variable-energy electron microbeam: a unique modality for targeted low-LET radiation.

We have designed and constructed a low-cost, variable-energy low-LET electron microbeam that uses energetic electrons to mimic radiation damage produced by gamma and X rays. The microbeam can access lower regions of the LET spectrum, similar to conventional X-ray or 60Co gamma-ray sources. The device has two operating modes, as a conventional microbeam targeting single cells or subpopulations of cells or as a pseudo broad-beam source allowing for direct comparison with conventional sources.

Evaluation of the new cesium-131 seed for use in low-energy x-ray brachytherapy.

Characterization measurements and calculations were performed on a new medical seed developed by IsoRay Inc. in Richland, Washington, that utilizes the short-lived isotope 131Cs. This model has recently received FDA 510(k) clearance.