ABSTRACT
High-brightness and short-pulse-width ( approximately 200 ps) x-ray lasers offer biologists the possibility of high-resolution three-dimensional imaging of specimens in an aqueous environment without the blurring effects associated with natural motions. As a first step toward developing the capabilities of this type of x-ray microscopy we have used a tantalum x-ray laser (lambda = 4.483 nm) together with an x-ray zone plate lens to image a test pattern. The observed image shows a detector-limited resolution of approximately 75 nm and paves the way to three dimensional biological imaging with high spatial resolution (20-30 nm).
Subject(s)
Algorithms , Tomography/methods , Biomedical Engineering , Computer Simulation , Electric Conductivity , HumansABSTRACT
We compared the reconstruction performance of six different impedance tomographic reconstruction algorithms in a two-dimensional computer simulation. We found the modified Newton-Raphson method applied to the finite-element method performed the best. We show that this method can also make a better one step correction in less time than any of the other methods.
Subject(s)
Algorithms , Electric Conductivity , Tomography/methods , Computer Simulation , ElectrodesABSTRACT
We discuss some physical results from an impedance camera. We placed agar blocks of various resistivities and sizes in saline. We showed that when the agar block was small or close in resistivity to the saline solution, we were unable to reconstruct it. We attempted to reconstruct an image of a fist, but were unable to achieve this due to current flowing in the arm. We concluded that three-dimensional analysis may be needed, along with more sensitive reconstruction algorithms and measurements.
