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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)
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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)
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)
Although there has been a recent increase in interest in picture archiving and communications systems (PACS) topics, little has been published to assist the non-technical person in understanding the complexities of the technologies required for a PACS implementation. This issue of Current Problems in Radiology defines each PACS component and explains why(More)
Energy imparted is a measure of the total ionizing energy deposited in the patient during a radiologic examination and may be used to quantify the patient dose in diagnostic radiology. Values of the energy imparted per unit exposure-area product, omega (z), absorbed by a semi-infinite water phantom with a thickness z, were computed for x-ray spectra with(More)
A male human tomographic model was used to calculate values of energy imparted (epsilon) and effective dose (E) for monoenergetic photons (30-150 keV) in radiographic examinations. Energy deposition in the organs and tissues of the human phantom were obtained using Monte Carlo simulations. Values of E/epsilon were obtained for three common projections(More)