For pretreatment QA, the authors found that this tool allowed verification of dwell positions and dwell times in about 6 min.

A phantom is proposed for quality control and calibration of instruments used for transillumination of the breast for early detection of cancer. A container is filled with a material having optical properties very similar to those of breast tissue, and internal objects are viewed by transmitted light. The phantom can be used to optimize operating conditions for the visualization of small or deep-seated lesions.

A recently proposed application of quantitative computed tomography is in the study of cerebral blood flow and partition coefficient using stable xenon as a freely diffusible, radio-opaque tracer. Central to the method is the calibration factor describing the relationship between CT number and xenon concentration in the brain. In this paper we examine the influence of temporal fluctuations, kVp, radial position and beam hardening on this calibration factor through the analysis of a series of phantom measurements. We conclude that under clinically realistic conditions and with correlations for temporal fluctuations, the error associated with the calibration factor is less than 2%. Furthermore, errors of this magnitude translate into errors of less than 3% in derived blood flow and partition coefficient values obtained using xenon-enhanced computed tomography.

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