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Medical uses of radiation have grown very rapidly over the past decade, and, as of 2007, medical uses represent the largest source of exposure to the U.S. population. Most physicians have difficulty assessing the magnitude of exposure or potential risk. Effective dose provides an approximate indicator of potential detriment from ionizing radiation and(More)
Introduces a novel approach for accomplishing mammographic feature analysis by overcomplete multiresolution representations. The authors show that efficient representations may be identified within a continuum of scale-space and used to enhance features of importance to mammography. Methods of contrast enhancement are described based on three overcomplete(More)
OBJECTIVE The purpose of this study was to determine how changes in radiographic tube current affect patient dose and image quality in unenhanced chest CT examinations. SUBJECTS AND METHODS Ten sets of CT images were obtained from patients undergoing CT-guided chest biopsies. For each patient, six images of the same region were obtained at settings(More)
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The number of diagnostic in vivo nuclear medicine (NM) procedures in the Province of Manitoba (population 1 million) has been examined over the period 1981 to 1985. The annual number of procedures performed has remained relatively constant at about 25 per thousand population. The isotope 99mTc accounted for 86% of all the studies performed and the number of(More)
PURPOSE To estimate the effective radiation dose to pediatric and adult patients at head and abdomen computed tomography (CT). MATERIALS AND METHODS Cylindrical water-equivalent phantoms were modeled for patients aged newborn to adult, and the energy imparted per unit axial exposure was computed. To determine the energy imparted to the simulated patients(More)
PURPOSE To determine the radiation effective dose to adult and pediatric patients undergoing abdominal computed tomographic (CT) examinations. MATERIALS AND METHODS Technique factors were obtained for three groups of randomly selected patients undergoing abdominal CT examinations: 31 children aged 10 years or younger; 32 young adults aged 11-18 years; and(More)
PURPOSE To determine effective dose (ED) per unit dose-length product (DLP) conversion factors for computed tomographic (CT) dosimetry. MATERIALS AND METHODS A CT dosimetry spreadsheet was used to compute patient ED values and corresponding DLP values. The ratio of ED to DLP was determined with 16-section CT scanners from four vendors, as well as with(More)
OBJECTIVE The purpose of our study was to determine typical organ doses, and the corresponding effective doses, to adult and pediatric patients undergoing a single CT examination. MATERIALS AND METHODS Heads, chests, and abdomens of patients ranging from neonates to oversized adults (120 kg) were modeled as uniform cylinders of water. Monte Carlo(More)