In the course of the unmanned exploration of the solar system, which the California Institute of Technology's Jet Propulsion Laboratory has managed for NASA, major advances in computerized image processing, materials research, and miniature electronics design have been accomplished. This presentation will show some of the imaging results from space exploration missions, as well as biomedical research tasks based in these technologies. Among other topics, the use of polymeric microspheres in cancer therapy will be discussed. Also included are ceramic applications to prothesis development, laser applications in the treatment of coronary artery disease, multispectral imaging as used in the diagnosis of thermal burn injury, and some examples of telemetry systems as they can be involved in biological systems.
Since Nuclear Magnetic Resonance was first used to image the human body in the late 1970's (1), image quality has steadily improved. At this time, image quality from magnetic resonance (MR) imaging, as it is now called, rivals that produced by x-ray computed tomography (CT). The cross-sectional tomographic images of the body produced by magnetic resonance display hydrogen density in the body, modified by the magnetic relaxation times, Tl and T2 (2). In addition to imaging the body, MR can also provide spectroscopic information from a specified region of interest within the body. Spectroscopy gives the concentration of different chemical species of the same chemical nucleus (e.g., P-31, C-13, Na-23), again modified by the magnetic relaxation times. Although such spectra have been obtained from the human body, the role of spectroscopy in clinical medicine has yet to be defined. The following discusses the indications for magnetic resonance imaging in current medical practice relative to existing imaging modalities such as CT. Potential future indications for magnetic resonance (including both imaging and spectroscopic applications) will be discussed.
Modern digital image processing hardware makes possible quantitative analysis of microscope images at high speed. This paper describes an application to automatic screening for cervical cancer. The system uses twelve MC6809 microprocessors arranged in a pipeline multiprocessor configuration. Each processor executes one part of the algorithm on each cell image as it passes through the pipeline. Each processor communicates with its upstream and downstream neighbors via shared two-port memory. Thus no time is devoted to input-output operations as such. This configuration is expected to be at least ten times faster than previous systems.
During the last decade, medical ultrasound has rapidly become a widely accepted imaging modality used in many medical specialties. It has the advantages that it is noninvasive, does not use ionizing radiation, is relatively inexpensive and is easy to use. Future trends in ultrasound include expanded areas of use, advanced signal processing and digital image analysis including tissue characterization and three dimensional reconstructions.
In the past 20 years, a substantial amount of effort has been expended on the development of computer techniques for enhancement of x-ray images and for automated extraction of quantitative diagnostic information. The historical development of these methods is described. Illustrative examples are presented and factors influencing the relative success or failure of various techniques are discussed. Some examples of current research in radiographic image processing is described.
This paper reviews a few of the more recent and most successful applications of medical imaging that have exploited the spatial resolution of computed tomography (CT) systems. Spatial resolution is, at this time, a distinguishing feature of high resolution CT scanners when compared to other medical imaging modalities. The purpose of this paper is to highlight these promising applications of digital imaging in medicine and similar applications of computer graphics, computer communications and bio-engineering that will develop using magnetic resonance and the new technologies that follow. Stereotactic techniques for neurosurgery and more recently orthopaedic surgery are outlined. In addition, techniques for custom structure modelling and prostheses planning and manufacturing are discussed. Finally, emerging issues of computer communications and their application to clinical imaging are introduced.
Most pathological conditions that arise within the human body are the result of underlying biochemical defects, and often the success or failure of subseq-uent treatment depends upon an early identification of these defects. For this reason, medical diagnostic techniques that reflect biochemical or metabolic behaviour have a special significance. One such technique, positron emission to-mography (PET), is based on the radiolabeling of substrates that are involved in the fundamental biochemical processes of the body. External detection and imaging of the radiation emitted by the radiolabel enables the chosen substrate to be monitored as it progresses along a particular metabolic pathway. In as far as the image of the emitted radiation reflects the biochemistry of the substrate in the body, abnormalities of biochemistry may be identified from the image. Thus, apart from the introduction into the body of a small quantity of radioac-tivity, PET is entirely non-invasive and without undue risk to the patient. To be successful, such an approach will require: the development of suitable instrumentation for imaging the radiation, the development of radiolabels with a well-understood fate within the body, the development of mathematical models that will explain in simple terms the kinetic behaviour of the tracers so as to distinguish pathology from normal function.