This article describes a technique in which X-ray transmission readings are taken through the head at a multitude of angles: from these data, absorption values of the material contained within the head are calculated on a computer and presented as a series of pictures of slices of the cranium. The system is approximately 100 times more sensitive than conventional X-ray systems to such an extent that variations in soft tissues of nearly similar density can be displayed.

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Computerized transverse axial scanning (tomography): Part I. Description of system. 1973.

/pdf/high-resolution-x-ray-computed-tomography-in-geosciences-a-3sj7249knj.pdf

High-resolution X-ray computed tomography in geosciences: A review of the current technology and applications

OBJECTIVE To describe a compact computed tomographic apparatus (Ortho-CT) for use in dental practice. METHODS Ortho-CT is a cone-beam-type of CT apparatus consisting of a multifunctional maxillofacial imaging machine (Scanora, Soredex, Helsinki, Finland) in which the film is replaced with an X-ray imaging intensifier (Hamamatsu Photonics, Hamamatsu, Japan). The region of image reconstruction is a cylinder 32 mm in height and 38 mm in diameter and the voxel is a 0.136-mm cube. Scanning is at 85 kV and 10 mA with a 1 mm Cu filter. The scan time is 17 s comparable with that required for rotational panoramic radiography. A single scan collects 512 sets of projection data through 360 degrees and the image is reconstructed by a personal computer. The time required for image reconstruction is about 10 min. RESULTS The resolution limit was about 2.0 lp mm-1 and the skin entrance dose 0.62 mGy. Excellent image quality was obtained with a tissue-equivalent skull phantom: roots, periodontal ligament space, lamina du...

Development of a compact computed tomographic apparatus for dental use.

Magnetic particle imaging (MPI) is a new tomographic imaging method potentially capable of rapid 3D dynamic imaging of magnetic tracer materials. Until now, only dynamic 2D phantom experiments with high tracer concentrations have been demonstrated. In this letter, first in vivo 3D real-time MPI scans are presented revealing details of a beating mouse heart using a clinically approved concentration of a commercially available MRI contrast agent. A temporal resolution of 21.5 ms is achieved at a 3D field of view of 20.4 x 12 x 16.8 mm(3) with a spatial resolution sufficient to resolve all heart chambers. With these abilities, MPI has taken a huge step toward medical application.

https://iopscience.iop.org/article/10.1088/0031-9155/54/5/L01/pdf

Three-dimensional real-time in vivo magnetic particle imaging

The paper gives a survey of the upcoming use of X-ray computed tomography (CT) for dimensional quality control purposes: i.e. for traceable measurement of dimensions of technical (mechanical) components and for tolerance verification of such components. It describes the basic principles of CT metrology, putting emphasis on issues as accuracy, traceability to the unit of length (the meter) and measurement uncertainty. It provides a state of the art (anno 2011) and application examples, showing the aptitude of CT metrology to: (i) check internal dimensions that cannot be measured using traditional coordinate measuring machines and (ii) combine dimensional quality control with material quality control in one single quality inspection run.

Computed tomography for dimensional metrology

A new and fundamentally different X-ray method is described. The cranium is scanned in successive layers by a narrow beam of X rays, in such a way that the transmission of the X-ray photons across a particular layer can be measured, and by means of a computer, used to construct a picture of the internal structure. Employing a suitably designed scanning gantry, a continuously operating X-ray tube, and a narrow collimated X-ray beam, the transmissions of X-ray photons across a slice of tissue may be measured by a system of crystal detectors in such a way that 28,800 readings are obtained. These form the basis of 28,000 simultaneous equations which are solved by a computer. The solutions are transformed into absorption coefficients and by means of a suitable algorithm related to their correct cells in a matrix of chosen size. The results are stored, computed, and then made available from a magnetic disc to construct a picture on a CRT. The numerical results are available from a print-out. The examin...

James Ambrose

Papers

Computerized transverse axial scanning (tomography). 2. Clinical application.