[Quantitative X-ray computed tomography].

Quantitative X-ray Computed Tomography (QCT) has an advantage to be able to determine three-dimensional bone density of lumbar vertebral body compared with dual energy X-ray absorptiometry (DXA) method. We introduced the high reproductable QCT method as a simplified manual operation avoiding simultaneous imaging of both patients and bone mass phantoms. The coefficient of variation of values measured by phantom study was 0.6% for 7 years in our hospital. In measuring of 144 healthy Japanese women, the bone mineral density of lumbar spine was most likely to be decreased linealy with age.