Showing papers on "Imaging technology published in 1992"

Computer and imaging technology's impact on stereotactic neurosurgery. A 1987-1991 update.

Abstract: Many improvements in computer and imaging technology have occurred since the last meeting of the American Society for Stereotactic and Functional Neurosurgery in 1987. These improvements are leading t

Compression and reconstruction of medical image sequences

Abstract: Many important imaging applications generate a sequence of images that are (or can be made to be) a spatially invariant image sequence with linearly additive contributions from the components that form the images. They include functional images in nuclear medicine, multiparameter MR imaging, multi-energy x-ray imaging for DR and CT, and multispectral satellite images. Recent results in the modelling and analysis of linearly additive spatially invariant image sequences are based on the inherent structure of such images, and can be used to achieve significant data compression for image storage and still provide good reconstruction. The technique is applied here to a human renogram, with compression of a very noisy 180-image sequence to a 4-image set. The resulting reconstruction illustrates the potential of the method.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Technique of Magnetic Resonance Imaging Assisted Simulation Based on Direct Coronal Imaging for Treatment Planning of Supradiaphragmatic Malignant Lymphoma

Abstract: In radiotherapy of malignant lymphoma radiotherapy has been delivered using opposed AP/PA large fields on linear accelerators for more than 20 years (Hoppe 1987; Wannenmacher et al. 1978). A basic precondition for treatment planning has always been the adequate localization of lymphoma, lymph node bearing areas, and organs at risk, which may have to be shielded by individual blocking. The procedure of localization is performed based on clinical, pathological, and imaging information. As imaging technology has evolved dramatically during the past two decades with the introduction of computed tomography (CT), ultrasound, digital subtraction angiography, and magnetic resonance imaging (MRI), the role of imaging has changed — becoming the most important tool in the localization procedure for malignant lymphoma nowadays. Nevertheless, the most widespread basic procedure for treatment planning in malignant lymphoma remains fluoroscopic imaging on the therapy simulator (Hoppe 1987; Timothy et al. 1989; Wannenmacher et al. 1978). Tumor, target volume, and organs at risk are defined on the X-ray simulation film based on information about the localization of tumor and target which must be “translated” from transverse cross-sectional, parallel projected imaging (mostly CT) onto the centrally projected coronal X-ray images, the simulation films. This rather complicated translation procedure entails many uncertainties, in particular a considerable risk of mislocalization.

One hundred years of imaging: new benefits, new challenges.

Abstract: Computed tomography and ultrasound, including Doppler vascular imaging, are now commonplace. Magnetic resonance imaging (MRI) is rapidly becoming a routine imaging option, while MRI spectroscopy is undergoing experimental evaluation. Positron emission tomography (PET) has undergone many years of research and is being used increasingly for functional imaging ofmetabolism of the brain and heart. With the added sophistication of these imaging modalities, interventional radiology has seen its options broadened. In addition to the improvements in radiologic imaging technology, computers are becoming a more integral part of the radiology department. Advances in digital imaging techniques have created exciting future possibiities for displaying "conventional" radiographs. Currently, digitized images can be transmitted within a hospital or even to another hospital for viewing on a display monitor. Technological innovations with diagnostic capabilities will continue to enhance the efficacy of the radiology department and challenge its departmental staff.

Desirable features of an infrared imaging system for aerodynamic research

Abstract: Advantage of non-intrusiveness, capability for field measurement, and increased availability of IR imaging systems have resulted in their wider use for aerodynamic research. However, certain difficulties persist while using currently available systems for such applications. A critical evaluation of the IR imaging systems is presented on the basis of the state-of-the-art of IR imaging technology and experiences in wind tunnel and flight testing at NASA's Langley Research Center. The requirements for using IR thermography as a measurement tool in aerodynamic research are examined in terms of range, sensitivity, and accuracy of temperature measurement, temporal and spatial resolution, and features of target. Deficiencies of present IR imaging systems are identified, and user precautions to avoid such problems by proper selection and operation of these units are suggested. Different aspects of imager performance such as imager optics, video capabilities, and environmental tolerance are discussed. Electronic data recording and image processing hardware and software requirements are evaluated. Slit response tests and spatial resolution are discussed with the objective of obtaining reliable, accurate, and meaningful information from IR thermography measurements for aerodynamic studies.

New Imaging Techniques

Abstract: Of the new imaging modalities, magnetic resonance imaging (MRI) seems to have acquired a particularly favorable track record in examinations of the knee. In addition to MRI, we shall also briefly discuss the diagnostic applications of sonography and computed tomography in this region.