Technical standardization for dual-energy x-ray absorptiometry

Abstract

Clinical applications of dual-energy X-ray absorptiometry (DXA) should be updated periodically to address new technologies and inconsistencies in the use of existing technologies. The 2003 Position Development Conference of the International Society for Clinical Densitometry addressed issues regarding hip and forearm regions of interest (ROIs), vertebral fracture assessment (VFA), quality assurance (QA), precision, and cross-calibration. Data are insufficient to determine whether the mean T-score of both hips can be used for diagnosis. However, the mean bone mineral density of both hips can be used for monitoring. The 33% radius is the preferred forearm ROI for the diagnosis of osteoporosis. Data are insufficient to determine indications and clinical utility of VFA. Minimum standards for a QA program were established. Phantom scanning should be performed at least once per week. Precision assessment should use patients representative of a DXA center's patient population. If a center has more than one technologist, then the average precision may be used. Repeat precision assessment is necessary if a new DXA system is installed or a technologist's skills have changed. Knowledge of precision is critical to DXA interpretation, and approval from an institutional review board should not be required. Practical standardized procedures for cross-calibration of DXA systems should be developed.