Description of a prototype emission-transmission computed tomography imaging system.
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We have developed a prototype imaging system that can perform simultaneous x-ray transmission CT and SPECT phantom studies. This system employs a 23-element high-purity-germanium detector array. The detector array is coupled to a collimator with septa angled toward the focal spot of an x-ray tube. During image acquisition, the x-ray fan beam and the detector array move synchronously along an arc pivoted at the x-ray source. Multiple projections are obtained by rotating the object, which is mounted at the center of rotation of the system. The detector array and electronics can count up to 10(6) cps/element with sufficient energy-resolution to discriminate between x-rays at 100-120 kVp and gamma rays from 99mTc. We have used this device to acquire x-ray CT and SPECT images of a three-dimensional Hoffman brain phantom. The emission and transmission images may be superimposed in order to localize the emission image on the transmission map. (+info)
POLAROID RADIOGRAPHS IN A NEUROSURGICAL PRACTICE.
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The use of the polaroid rapid radiographic method has proven to be very useful in the field of neurosurgery as well as in other fields. It has many wide applications and is gaining increasing popularity. Its numerous advantages far outweigh its minor disadvantages. (+info)
RETOUCHING OF RADIOGRAPHS.
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Underexposed or underdeveloped radiographs which could have been used for teaching or publication were treated prior to photographing with a technique similar to that used for photographic negative retouching. This method enables these radiographs to be used for diagnostic demonstration, where before they would have been condemned as unsuitable for reproduction. The method is simple and requires very little experience or equipment. (+info)
TRANSHEPATIC CHOLANGIOGRAPHY.
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Percutaneous transhepatic cholangiography is a method of visualizing the biliary tree by the injection of radio-opaque medium through the abdominal wall and liver into an intrahepatic bile duct. The procedure is indicated in the immediate preoperative evaluation of patients with obstructive jaundice of unknown etiology and is usually diagnostic in these cases. It may also be of value in avoiding operation in poor-risk patients with obstructive jaundice. Biliary leak resulting in chemical peritonitis is a complication in about 5% of these procedures. Intraperitoneal hemorrhage is a complication in less than 1%. Death results from the procedure in less than 0.5% of cases. Transhepatic cholangiography during surgical operation is of value in demonstrating obstructive lesions of the bile ducts. However, preoperative percutaneous transhepatic cholangiography is preferred, since it makes possible adequate preparation for technically difficult repairs and resections. (+info)
Interpretive Structural Modeling for introducing of image information system at the middle-scale hospitals.
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We extract and analyze the decision factors of introducing image information system by ISM (Interpretive Structural Modeling) method to determine the criteria and structure for system selection. As a result, 15 factors were extracted, and the structure and relation among factors became clear. (+info)
Progress toward paperless radiology in the digital environment: planning, implementation, and benefits.
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A growing number of hospitals have installed PACS (Picture Archiving and Communications Systems) in order to improve patient care and to facilitate improved efficiencies. While eliminating films is commonly one of the first goals in planning a successful PACS implementation, eliminating the manual handling of paperwork can also produce a substantial benefit. We describe the process utilized at Maine Medical Center (MMC) to achieve a substantial degree of freedom from paperwork. Some of the benefits were expected, but some unexpected benefits also revealed themselves during this process. (+info)
Physical principles and technology of clinical PET imaging.
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Molecular imaging with positron-emitting radionuclides is playing an increasingly important role in the diagnosis and staging of malignant disease and in monitoring response to therapy. To meet this challenge, significant improvements in the performance of the imaging technology have been achieved in recent years. Such developments are subject to the constraints imposed by the physics of positron emission tomography (PET) and the main objectives in designing or improving PET scanners are to achieve high spatial resolution and sensitivity while maximising the true coincidence count rate relative to contributions from noise processes. Noise contributions in PET include not only statistical effects associated with photon counting but also background processes such as scatter and random coincidences. The recent developments of new, faster scintillators and electronics for PET detectors, as well as statistically-based algorithms that reconstruct fully three-dimensional (3D) PET images in minutes, have dramatically reduced clinical imaging times while improving image quality. A recent advance, the combination of functional imaging and computed tomography (CT) in the PET/CT scanner has further reduced the study duration by eliminating the lengthy PET transmission scan and providing accurate anatomical localisation of functional abnormalities. PET imaging technology has now improved to where a combined anatomical and functional clinical study can be completed in less than 10 minutes--although taking advantage of such high throughput potential will challenge patient management in diagnostic imaging departments. This paper reviews the physical principles underlying PET and summarises the recent developments in PET scanner technology, from the introduction of new PET detectors to the development of the combined PET/CT scanner. (+info)
Radiology: "killer app" for next generation networks?
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The core principles of digital radiology were well developed by the end of the 1980 s. During the following decade tremendous improvements in computer technology enabled realization of those principles at an affordable cost. In this decade work can focus on highly distributed radiology in the context of the integrated health care enterprise. Over the same period computer networking has evolved from a relatively obscure field used by a small number of researchers across low-speed serial links to a pervasive technology that affects nearly all facets of society. Development directions in network technology will ultimately provide end-to-end data paths with speeds that match or exceed the speeds of data paths within the local network and even within workstations. This article describes key developments in Next Generation Networks, potential obstacles, and scenarios in which digital radiology can become a "killer app" that helps to drive deployment of new network infrastructure. (+info)