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CONTEXT Cardiac computed tomography (CT) angiography (CCTA) has emerged as a useful diagnostic imaging modality in the assessment of coronary artery disease. However, the potential risks due to exposure to ionizing radiation associated with CCTA have raised concerns. OBJECTIVES To estimate the radiation dose of CCTA in routine clinical practice as well as(More)
We present a theoretical overview and a performance evaluation of a novel z-sampling technique for multidetector row CT (MDCT), relying on a periodic motion of the focal spot in the longitudinal direction (z-flying focal spot) to double the number of simultaneously acquired slices. The z-flying focal spot technique has been implemented in a recently(More)
OBJECTIVES To assess the accuracy of dual-energy CT (DECT) for diagnosing gout, and to explore whether it can have any impact on clinical decision making beyond the established diagnostic approach using polarising microscopy of synovial fluid (diagnostic yield). METHODS Diagnostic single-centre study of 40 patients with active gout, and 41 individuals(More)
C urrently, computed tomographic (CT) imaging of the heart is mainly used for the quantification of coronary artery calcification as an indirect measure of coronary plaque burden 1,2 and, less frequently, for minimally invasive coronary angiography. 3 CT imaging of the heart and coronary arteries without unsharpness due to motion artifact first became(More)
A preliminary report on medical radiation exposures to the US population based on publicly available sources of data estimated that the collective dose received from medical uses of radiation has increased by Ͼ700% between 1980 and 2006. 1 Computed tomography (CT) has had an annual growth rate of Ͼ10% per year and accounted for Ϸ50% of the collective dose(More)
This document presents recommendations of the American Association of Physicists in Medicine (AAPM) for quality assurance of computed-tomography- (CT) simulators and CT-simulation process. This report was prepared by Task Group No. 66 of the AAPM Radiation Therapy Committee. It was approved by the Radiation Therapy Committee and by the AAPM Science Council.
In spiral computed tomography (CT), dose is always inversely proportional to pitch. However, the relationship between noise and pitch (and hence noise and dose) depends on the scanner type (single vs multi-detector row) and reconstruction mode (cardiac vs noncardiac). In single detector row spiral CT, noise is independent of pitch. Conversely, in noncardiac(More)
Current guidelines and literature on screening for coronary artery calcium for cardiac risk assessment are reviewed for both general and special populations. It is shown that for both general and special populations a zero score excludes most clinically relevant coronary artery disease. The importance of standardization of coronary artery calcium(More)
Contingent color aftereffects (CAEs, or McCollough effects) were induced using two pairs of orthogonally related patterns (horizontal/vertical and concentric/radial) to determine whether the CAEs of the four patterns are independent. Tests using composite test patterns (like those employed by Emerson, Humphrey, & Dodwell, 1985) suggested independent(More)