The COBRA method is a fast and accurate method for BT filter characterization, which requires a simple experimental setup in a clinical environment. Because of the ease of data acquisition, multienergy scans can be acquired which allow characterization of the BT filter thickness.

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Cardiovascular diseases are now the world's leading cause of death. To reduce high rates of such preventable premature deaths, evidence-based approaches to heart health promotion must be disseminated across public health systems. To succeed, we must build capacity to disseminate strategies that are practical and effective. However, we know little about such dissemination, and we lack both conceptual frameworks to guide our thinking and appropriate scientific methodologies. This article presents conceptual and analytic frameworks that integrate several approaches to understanding and studying dissemination processes within public health systems. This work is based on the Canadian Heart Health Dissemination Project, a research program examining a national heart health dissemination initiative. The primary focus is the development of a systematic protocol for measuring levels of capacity and dissemination, and determining successful conditions for, and barriers to, capacity and dissemination, as well as the nature of the relationship between these key concepts.

Half-value layer (HVL) measurements on commercial whole body CT scanners require serial measurements and, in many institutions, the presence of a service engineer. An assembly of aluminum filters (AAF), designed to be used in conjunction with a real-time dosimeter, was developed to provide estimates of the HVL using clinical protocols. Two real-time dose probes, a solid-state and air ionization chamber, were examined. The AAF consisted of eight rectangular filters of high purity aluminum (Type 1100), symmetrically positioned to form a cylindrical “cage” around the probe’s detective volume. The incident x-ray beam was attenuated by varying thicknesses of aluminum filters as the gantry completed a minimum of one rotation. Measurements employing real-time chambers were conducted both in service mode and with a routine abdomen/pelvis protocol for several combinations of x-ray tube potentials and bow tie filters. These measurements were validated against conventional serial HVL measurements. The average relative difference between the HVL measurements using the two methods was less than 5% when using a 122 mm diameter AAF; relative differences were reduced to 1.1% when the diameter was increased to 505 mm, possibly due to a reduced scatter contamination. Use of a real-time dose probe and the AAF allowed for time-efficient measurements of beam quality on a clinical CT scanner using clinical protocols.

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