Non-invasive method of forming prostheses of skeletal structures internal to a body for use in reconstructive surgery. The selected internal skeletal structure is measured by subjecting the body to radiant energy to produce radiant energy responses that are detected to obtain representations delineating the skeletal structure. Three dimensional coordinate data defining the skeletal structure is generated from the obtained representations. The coordinate data is employed to control a sculpting tool to form the prosthesis.

Method of forming implantable prostheses for reconstructive surgery

A device and method is provided for finding a specific material superimposed on an unknown background when the locations of the specific material and the background are unknown, for example, inside an item of baggage. The invention comprises exposing an area of an item to be inspected to x-rays of two substanitally different energies, making effective use of the characteristic material specific differences in photoelectric effect scattering and Compton scattering, and comparing the pairwise differential attenuation of the x-rays at nearby exposed subareas to determine whether differences in attenuation can be attributed to the presence of different amounts of the specific material overlying the respective subareas. The most probable subareas are indicated on a standard image on a monitor as being the most likely location of the overlying specific material.

Device and method for inspection of baggage and other objects

A condensed review of recent advances accomplished in the development and the applications of noninvasive tomographic and velocimetric measurement techniques to multiphase flows and systems is presented. In recent years utilization of such noninvasive techniques has become widespread in many engineering disciplines that deal with systems involving two immiscible phases or more. Tomography provides concentration, holdup, or 2D or 3D density distribution of at least one component of the multiphase system, whereas velocimetry provides the dynamic features of the phase of interest such as the flow pattern, the velocity field, the 2D or 3D instantaneous movements, etc. The following review is divided into two parts. The first part summarizes progress and developments in flow imaging techniques using γ-ray and X-ray transmission tomography; X-ray radiography; neutron transmission tomography and radiography; positron emission tomography; X-ray diffraction tomography; nuclear magnetic resonance imaging; electrica...

Noninvasive Tomographic and Velocimetric Monitoring of Multiphase Flows

This paper reviews the major developments that have taken place during the last three years in imaging with computed tomography (CT) using X-ray, emission, and ultrasound sources. Space limitations have resulted in some selection of topics by the author. There are four major sections dealing with algorithms, X-ray CT, emission CT, and ultrosound CT. Since most of the currently used algorithms are of filtered-backprojection type, we have concentrated on these in the section on algorithms (with emphasis on their implementation aspects). In X-ray CT an important question raised during the last few years has concerned the parameter measured by a CT scanner, given the fact that the X-rays used in CT scanners are polychromatic and the fact that tissue attenuation coefficients are energy dependent. Answers to this question are reviewed in the section on X-ray CT where we have also discussed the artifacts caused by the polychromaticity of the X-ray photons. Methods for the removal of these artifacts have also been reviewed. In emission CT the biggest development of the last three years is the great interest in positron tomography, although space constraints have dictated an essentially introductory treatment and not all aspects of the single photon and positron tomography have been surveyed. Finally, we have reviewed recent developments in ultrasound CT. We have pointed out that because of the sensitivity of this technique to refraction, it is currently limited to soft tissue structures, with ultrasonic detection of tumors in the female breast a significant application.

Computerized tomography with X-ray, emission, and ultrasound sources

The rapid rate at which the field of digital picture processing has grown in the past five years had necessitated extensive revisions and the introduction of topics not found in the original edition.

Table of Contents

Introduction. Mathematical Preliminaries. Visual Perception. Digitization. Compression. Enhancement. Restoration. Reconstruction. Index.

Digital Picture Processing, Volume 1

Convolution reconstruction of fan beam projections

A fan-shaped beam of penetrating radiation, such as X-ray or γ-ray radiation, is directed through a slice of the body to be analyzed to a position sensitive detector for deriving a shadowgraph of transmission or absorption of the penetrating radiation by the body. A number of shadowgraphs are obtained for different angles of rotation of the fan-shaped beam relative to the center of the slice being analyzed. The detected fan beam shadowgraph data is reordered into shadowgraph data corresponding to sets of parallel paths of radiation through the body. The reordered parallel path shadowgraph data is then convoluted in accordance with a 3-D reconstruction method by convolution in a computer to derive a 3-D reconstructed tomograph of the body under analysis. In a preferred embodiment, the position sensitive detector comprises a multiwire detector wherein the wires are arrayed parallel to the direction of the divergent penetrating rays to be detected. A focussed grid collimator is interposed between the body and the position sensitive detector for collimating the penetrating rays to be detected. The source of penetrating radiation is preferably a monochromatic source.

Fan beam X- or γ-ray 3-D tomography

A fan-shaped beam of penetrating radiation, such as X-ray or γ-ray radiation, is directed through a slice of the body to be analyzed to a position sensitive detector for deriving a shadowgraph of transmission or absorption of the penetrating radiation by the body. A number of such shadowgraphs are obtained for different angles of rotation of the fan-shaped beam relative to the center of the slice being analyzed. The detected fan beam shadowgraph data is reordered into shadowgraph data corresponding to sets of parallel paths of radiation through the body. The reordered parallel path shadowgraph data is then convoluted in accordance with a 3-D reconstruction method by convolution in a computer to derive a 3-D reconstructed tomograph of the body under analysis. In a preferred embodiment, the position sensitive detector comprises a multiwire detector wherein the wires are arrayed parallel to the direction of the divergent penetrating rays to be detected. A focussed grid collimator is interposed between the body and the position sensitive detector for collimating the penetrating rays to be detected. The source of penetrating radiation is preferably a monochromatic source.

Method and apparatus for X-ray or γ-ray 3-D tomography using a fan beam

A fan-shaped beam or a fan array of individual beamlets of penetrating radiation, such as X-ray or γ-ray radiation, is directed through a planar slice of the body to be analyzed to a position sensitive detector. The fan beam and the detector are caused to move in a rectilinear or nearly rectilinear fashion so that the individual beamlets or rays of penetrating radiation scan across the body and each detector records a parallel ray shadowgraph at a different angle of rotation (scan angle) with respect to the body and covering a range of scan angles less than 180° and typically approximately 90°. The recorded shadowgraphic data is then reconstructed into a 3-D tomograph of the body using a method of successive approximations. The resultant scanner may be used to analyze planes of the body parallel to the major axis thereof such as saggital or coronal as well as transaxial planes. In a preferred embodiment, the position sensitive detector includes detector elements arranged for detecting penetrating radiation passing through the body in a number of divergent planes diverging from the source. 3-D tomographs are reconstructed from the corresponding divergent plane shadowgraphic data. An advantage in use of the scanner of the present invention is that faster scan times are achieved due to the rectilinear or nearly rectilinear translation of the scanner which enables a reduction of blurring of the resultant tomographs due to biological motion. A further advantage is that multiple planes may be scanned simultaneously.

Limited scan angle fan beam computerized tomography

A fan-shaped beam of penetrating radiation, such as X-ray or γ-ray radiation, is directed through a slice of the body to be analyzed to a position sensitive detector for deriving a shadowgraph of transmission or absorption of the penetrating radiation by the body. A number of such shadowgraphs are obtained for different angles of rotation of the fan-shaped beam relative to the center of the slice being analyzed. The detected fan beam shadowgraph data is reordered into shadowgraph data corresponding to sets of parallel paths of radiation through the body. the reordered parallel path shadowgraph data is then convoluted in accordance with a 3-D reconstruction method by convolution in a computer to derive a 3-D reconstructed tomograph of the body under analysis. In a preferred embodiment, the position sensitive detector comprises a multiwire detector wherein the wires are arrayed parallel to the direction of the divergent penetrating rays to be detected. A focussed grid collimator is interposed between the body and the position sensitive detector for collimating the penetrating rays to be detected. The source of penetrating radiation is preferably a monochromatic source.

Douglas P. Boyd

Papers

Convolution reconstruction of fan beam projections

Fan beam X- or γ-ray 3-D tomography

Method and apparatus for X-ray or γ-ray 3-D tomography using a fan beam

Limited scan angle fan beam computerized tomography

Position sensitive X-ray or γ-ray detector and 3-D tomography using same