Bone mineral determination using dual photon absorptiometry

为了定量测量椎体骨密度，研制了高精度、高精度的伽马相机双光子吸收测量系统，并进行了临床研究。正常女性附件骨BMD随年龄增长而降低，主要由皮质骨(第2掌骨和桡骨远端1/3)和中轴骨(主要由松质骨组成)和中轴骨(腰椎整体或松质骨)随年龄增长而减少，绝经后下降尤为明显。此外，女性的骨丢失发生的时间比男性更早，程度也比男性更严重。轴骨的起始骨丢失早于附件骨，骨丢失的速度也比附件骨明显。骨密度值与甲状旁腺素浓度之间无明显相关性。骨组织形态计量学显示少数低BMD值的患者为低翻转骨型。在日本，骨质疏松症的发病率将呈上升趋势。慢性肾功能衰竭时，椎体骨密度值由低到高分布，1~5年有透析史或轻度继发性甲状旁腺功能亢进症(SHP)者有较高的椎体骨密度，而有5年以上病史或重度SHP者有较低的放射状BMD。此外，放射骨和椎骨的BMD值的差异，例如。桡骨低，脊椎高，被认为是。这些结果表明，为了阐明肾性骨营养不良的骨病理生理机制，皮质骨和松质骨的骨密度测量是必不可少的。

In order to quantifying the vertebral bone mineral density(BMD), highly accurate and precise dual photon absorptionmetry(DPA) system using gamma camera was developed, and clinical study was done. In normal females the BMDs in both appendicular bone, mainly consisted of cortical bone(2nd metacarpal bone and 1/3 distal radius), and axial bone, mainly composed of trabecular bone(integral or trabecular bone of lumbar betebra), decreased with aging, especially in post-menopause. Furthermore, the bone loss in females occurred earlier in life and more severe in its grade than that in males. Also, the initiation and the rate of bone loss in axial bone were earlier and more prominent than appendicular bone. No high relation between BMD values and PTH concentrations was observed. The bone histomorphometry wich was performed in few cases with low BMD values showed the low turn-over bone type. Thus, it would be expected that the bone mineral determination was useful in the early diagnosis, the anticipation of fracture risk and the therapeutical response of osteoporosis, which would be increasing in the incidence in Japan in future.In chronic renal failure, the vertebral BMD values distributed from low to high, and high vertebral BMDs were observed in cases with 1-5 yrs.-history of dialysis or mild secondary hyperparathyroidism(SHP), while the low radial BMDs were observed in cases with more than 5 yrs.-history or severe SHP. Furthermore, the discrepancy of radial and vertebral BMD values, eg. low in radius and high in vertebra, was recognised. These results indicate that, to clarify the bone pathophysiology in renal osteodystrophy, the measurement of BMD in both cortical and trabecular bone is essential.