[The quantitative determination of bone mineral content--a system comparison of similarly built computed tomographs]

An intercomparison of 4 CT scanners of the same manufacturer was performed. The bone mineral content of 11 lumbar vertebral columns removed directly post mortem was determined in a specially constructed lucite-water phantom. Even devices of the same construction were shown to yield a variation in the quantitative evaluation markedly exceeding the annual physiological mineral loss. As long as scanner adjustment by physical calibration phantoms has not yet been established, a course assessment and therapy control of bone mineral content should always be carried out on the same QCT scanner.